US2306988A - Wet vacuum pump apparatus - Google Patents

Description

De.29,1942. H. E. ADAMS l 2,306,988

WET VACUUM PUMP'APPARATUS Filed Aug.l 2, 1940 4`SheetS-Sheef; l

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2,306,988 WET VACUUM PUMP APPARATUS Harold E. Adams, South Norwalk, Conn., or to Nash Engineering Company,

assim- South Norwalk, Conn., a corporation ot Connecticut Application August 2, 1940, Serial No. 349,955

(ci. ias-s) 32 Claims.

This invention relates to a wet vacuum pumping apparatus and a primary object is to provide such an' apparatus in which the air and water of a system are separated, the air being exhausted by means of one pumping medium and delivered into the atmosphere, while the water is being withdrawn by another pumping medium and discharged against any desired pressure.

Automatic means may be provided whereby operation of the pumping elements is controlled in accordance with the vacuum, the quantity of water returned, or both. f

As an illustration of one type of system to which the invention may be applied, reference may be made to the Reissue Patent No. 15,637 to Irving C. Jennings, reissued June 26, 1923, wherein the apparatus is used for the collection of condensed liquid gathered from the return side of the system, and the discharge of this conden-x sate from the returns to the boiler; or other desired point, and at the same time to remove the air and noncondensable gases in the returns, for the maintenance of the desired sub-atmospheric pressure on the returns, thus providing for the circulation of steam throughout the heating system, in a manner commonly practiced in modern heating systems.

It will be understood, however, that the description of this apparatus as applied to a heating system is solely for purposes ofrillustration, as the apparatus may be adapted to any service Where the removal of a gas or liquid from any type of system or container is required.

It has been the practice in the past to use entirely separate pumps for handling liquids and gases, although such pumps may be housed in a common casing, or mounted on a common driveshaft. 'I'his practice has been improved, however, by the development of a successful arrangement combining the liquid and gas rotors into a single unit, as well as utilizing a single casing and compartment, thus reducing the size and cost of the unit, while at the same time increaslng the eflciency and decreasing the power requirements heretofore accepted. Such developments form the subject-matter of a copending application of Harold E. Adams, Serial No. 349,- 953, led August 2, 1940.

One of the objects of the present invention includes the utilization and adaptation of such a combined pumping unit in the wet vacuum pumping apparatus forming the subject-matter of the present invention.

Another object of the present invention is to It is customary to utilize pumps of the centrifugal type to handle liquids in apparatus of "this nature, and it is a further object of the invention to improve the eiiiciency of such a centrifugal. With the vertical mounting just mentioned, the impeller of the centrifugal can be placed in such a manner that the inlet or eye to the impeller extends upwardly from the horizontal, instead of downwardly, as is usually the 'custom in vertically mounted units, and also located at the lowest part of the inlet to the pump casing. With this mounting, not only will the liquid pump be self-priming, but it will .also be self-venting, and tendency towards trapping of gas or air bubbles which would impair the eiliciency of the pump, is avoided. 'From' this fol- -lows the further advantage that gas and air will not be pumped from the discharge of the liquid pump to the boiler or other parts of a system where such air or gas would 'otherwise enhance the tendency towards corrosion in such parts.

Another feature of the present invention resides -in the provision of means closing off the discharge line from the liquid imJpeller untill such time as there is liquid to be pumped, thus preventing any air or gas which may be in the return side of the system from being passed on to the supply side. The importance of this feature cannot be emphasized'too much, since it is well known that in most of the present day combined liquid and gas pumping apparatus, air or gas could pass through the liquid side of the apparatus with deleterious results to the system.

Still another object contemplates controlling the cut-o-ii' for Athe liquid discharge from the pump by the level of liquidin the receiver for the returns of the system and thereby, by preventing air 'flow through the discharge from the pump, keep the working elements of the' pum constantly primed and submerged.

An advantage accruing as a result of these fea-v tures is the elimination of surging, by relieving obtain various advantages by mounting the comthe liquid pump from the necessity of constantly losing, and picking up, liquid from the receiver,

thereby maintaining a constant'elcient opere.-l

tion.

In keeping withthe foregoing objects of compactness and location of parts with relation to each other and to the system, to obtain maximum efficiency with minimum power requirements, a further feature resides in the use of an extremely close coupled sealing arrangement between the pump and the prime mover by which the pump is driven, such that a common wall may be provided to form the motor end shield and the upper casing wall of the pump.

Another, and important object, is to provide a mechanical seal for the drive-shaft, of a nature facilitating the close coupling. To the attainment of the foregoing and other objects which will appear as the description proceeds, reference may be made to the accompanying drawings, in which: l

Figure 1 is an elevation of an illustrative, typ ical heating system showing application of the v apparatus thereto;

Figure 2 is an elevation, partly in section, through the apparatus;

Figure 3 is a section through the separator showing the arrangement of float control valves;

Figure 4 is a section through the Dumping mechanism taken approximately at-right angles to the showing of Figure 2;

vFigure 5 is a diagrammatic section through the y float switch of thereceiver, modified from the ply line B, radiation C, a return line D, and the wet vacuum pumping apparatus generally indicated at E, interposed between the return and supply sides of the system. lThe return line D is connected to suitable risers F running to the individual radiators and the supply line Bis similarly connected to risers G.v

The pumping apparatus is directly connected through its receiver to the main return line D, and is connected by a discharge line H to the boiler, completing the circuit. An equalizer line I equipped with a check valve opening in the direction of the supply is provided to balance pressures between the supply and return sides, in the event that the pressure in the supply should tend to drop below the pressure in the returns.

Extending from the top of the receiver is a vent line J, this line being equipped with a check valve opening in the direction of the returns for the purpose of venting the receiver to a, high point in the returns. An additional check valve K is tapped into the line J, for venting the receiver and system to atmosphere under such conditions-as when the returns are under a pressure higher than atmospheric.

The separator tank of the pumping apparatus is provided with an air discharge L in the conventional manner, in fact the entire system as ratus indicated generally at E in Figure 1 is shown enlarged and partly in section. This apparatus comprises generally, a dual pumping unit III driven by a prime mover, illustrated herein as the motor M, through a drive shaft II. ceiver I2 connected to the return line Dl receives returns from the system, such returns passing through the strainer I3 to the interior of the receiver which functions as an initial separating tank, separating gases from liquids which enter the receiver. 'I'he dual pumping unit I0 includes the-liquidV ring type, gas compressor I4 and the centrifugal, or other equivalent type of liquid pump liformed as compartments of a common or unitary pump housing. A dual impeller comprising a rotatable central partition and driving disc II is lformed with vanes I1 operative in the liquid ring or gas compressing side of the pump, and on its other face is provided with conventional centrifugal impeller blades I8, operating in the liquid handling side of the pump. The liquid handling side of the pump is connected to the lower portion of the receiver by a suction passage Il which thus forms an inlet to the eye of the centrifugal impeller. The liquid ring pump -or gas compressor is formed with a port cone 20 having an inlet port 2I leading to the compressing chamber. The port cone 20 is connected to the upper part of the receiver by a suction line which `includes the passages 22 and' 23, and an inlet pipe 2l which extends within the receiver substantially to the top thereof. With this arrangement it will thus be seen that when the dual pump is in operation liquids can be drawn from the lower part of the receiver and gas which separatesfrom such liquids and rises, may be drawn from the upper part of the receiver.

It is essential, in a pump of the type herein employed, that means be provided to seal the liquid side of the` pump from the gas side, in fact this innovation of combining such dissimilar elements in one rotating member is made possible by various sealing arrangements, as described in the companion application, Serial No. 349,953 above mentioned, and herein, that enable the gas pump and the liquid pump to operate satisfactorily in such close relationship.

'I'he performance of liquid pumps, as is well known in the art, is susceptible to inefficiency, caused by traces of gas being mixed with the liquid, such a mixture resulting in thel breaking down of the centrifugal action, due to the presence of lighter lgas bubbles.' On the other hand a gas compressor is very sensitive to the quan- I is assured of a supply of liquid at the inlet to thus far described is old and conventional, and

Referring now to Figures 2 and 4, the appa,- 75' this pump, the presence of this liquid being assured, if necessary, by automatic float control of the discharge, or a pressure relief valve located in the discharge, or other similarmeans where there is a possibility ofthe suction side 1lieiing uncovered due to a limited supply of liq- The gas pump or compressor side' may operate either as a vacuum pump, where its normal discharge pressure would be atmospheric, or it may operate as a gas compressor over any usual presescasas Y i '3 sure ranfgecompatible with its design and proportions.

It is furthermore assumed that the gas pump or compressor is sealed with the same type of liquid that is being pumped by the liquid pump itself, in fact primary seals-will be eifected by liquid from the centrifugal, under the pressures of the centrifugal pump.

Make-up sealing liquid can be introduced into the gas pump or compressor by any of the conventional methods now used. In the drawings (Fig. 3) one method is illustrated, wherein makeup sealing water may be introduced from the suction passage I3 through an orifice 25 and a strainer 23 into the gas pump suction line 23.

One of the lobes or displacement chambers of the gas pump is indicated at 21. On either side of the chamber are provided circumferential sealing surfaces, as at 28 and 29. Anadditional set of circumferential sealing surfaces is formed at 30, sealing against the pressure developed by the water end of the centrifugal impeller in the volute 3l. The sealing surfaces 28 and 33 in the illustrated design are provided by forming concentric ribs on the under side of 25 the driving disc i3, the sides of these ribs mating with shoulders on the gas compressor housing. Liquid from the centrifugal pump entering under pressure into the running clearance between these surfaces forms the seal. Obviously,'

however, the formation of the surfaces can bevaried, one example being the surfaces which form the seal 23.

An annular chamber 32 will be formed between the two sealing surfaces 28 and 33, which may be regarded as a leakage chamber separating thel seals. A drilled orifice 33 of a predetermined definite size (according to thev size of the pump),

establishes communication between this annular chamber 32 and an outer chamber 34, this outer chamber being'an irregular annular space formed between the' outer 'walls' 35 of the gas pumpportion of the combined impeller rotor. If the 50 chamber 42, it is possible thus to control autopressure in the annular chamber 32 is materially higher than the discharge pressure of the gas pump, it will force an 'excessive amount of sealing liquid through the sealing surfaces at 28 and overload the vacuum or gas pump end of the apparatus with an `unnecessary amount of sealing liquid, resulting in increased power requirements and lowered efficiency of this unit.

It is for the purpose of limiting the formation of excess pressure about the sealing surface 28 that the additional sealing surfaces and orifices 33 are provided. Liquid pump impeller-gas pump rotor combinations may be made with impeller diameters and rotor diameters of widely varying values according to the particular surface to which they are applied. 'I'he vacuum pump rotor diameter will be varied to suit the rotational speed of the driving motor, whereby to give a fairly constant peripheral velocity to the outer diameter of this rotor. The peripheral speed of the liquid impeller, however, may vary widely according to the pressure at which it is designed to deliver the liquid.

Commercial vacuum heating pumps, such as used in the heating system herein illustrated,

impeller at from ilve to fifty pounds gage discharge pressure, according to the steam supply system in which they are applied. This, there-- fore, requires a specific diameter of liquid impeller for each` designed pressure service.

It follows then, that while the designed pressure in the volute 3i of different units may vary over the range indicated, the pressures in the lobe 21 will be fairly constant for all services,4 inasmuch as the vacuum or gas pump is deliversuch as 28, between the lobe'21 and volute 3i, there would be a wide variation in the requirements for maintaining tightness at this point. A sufllciently tight joint at this location might be provided but conceivably it would be difllcult to maintain tightness in the joint over years of service. Again, a replaceable seal might be used, to maintain tightness at the joint, but a better method of controlling the pressure differential at this point is provided by the sealing arrangement being described. The primary sealing surface 32 takes care of the initial pressure drop from the volute 3l to the annular chamber 32. `The relief orifice 33 relieves the leakage thus entering the annular chamber by establishing communication for drainage purposes into the cham- 'ber 34. Sealing liquid entering the chamber 34 is drained off through control means hereinafter described, by means of which the pressure in the chamber 34 is regulated in a manner providing 35 maintenance of 'a fairly constant pressure therein, and hence on the sealing surfaces at 28.

'There are several alternative means of regulating pressures in the chamberv 34, as indicated in Figs. 3, 4 and 6. A preferred means or meth- 40 od of control of pressure in the chamber 34 is illustrated in Figs. 3 and 4, wherein is provided a connection 40 establishing communication through a pipe or cored passage 4I to which it is normally connected, this connection communicating freely with atmospheric side of a separator chamber 42. Communication is thus established between the lower or submerged part of the chamber 42 and the chamber 34. By connecting the chamber 34 freely with the separator matically the pressure in the chamber 34, at approximately atmospheric pressure, and by this connection the pressure around the sealing surfaces 28 is kept from deviating much from atmospheric pressure which, in the case of the heating pump illustratedherein, is the discharge pressure of the vacuum pump element of the rotorimpeller. The separator chamber 42, during the normal operation of the pump is at a pressure just slightly above atmosphere, and is fairly con- 34. that water relieved from the annular space or chamber 32 will be bled olf into the separator chamber, and essentially keep the chamber 34 slightly above atmospheric pressure. The excess leakage water bled olf by the orifice 33 after delivery into the separator Will beI returned to the inlet side of the liquid pump through the passage I9. In this manner a fairly constant desired pressure, slightly in excesss of atmospheric pressure, will be maintained in the annular chamber may be required to deliver liquid handled by this 32 and at the adjacent sealing surfaces.

32 and at the adjacent sealing surfaces 28.

An additional means of providing a liquid seal around the sealing surface 29 and also at the surfaces 43 is provided by the addition of an orifice 44 (Fig. 4), which establishes communication to saidv surfaces from a protecting screen or strainer 45 through the ported passage 4B. The function of the orifice 44 is to limit the liquid seal supply to the sealing surfaces 29 and 43, to the desired amount.

A variation in the methods of controlling pressures in the chamber 34, illustrated in Fig. 3, is eiected by bleeding oil the leakage into this chamber, through a restricted connection 41, to the vacuum or low pressure side of the apparatus. The connection 41 is provided with a suitably proportioned orice 48, effective to prevent the lowering of the pressure in'the chamber 34 completely to that of the vacuum side of the pump, as a complete lowering of pressure would be detrimental, and prevent maintenance of suf' fcient sealing pressure in the annular chamber 32, for the proper sealing of the surfaces at 28 and 29.

The use of the connection 41 would be resorted to in cases of combinations using liquid impellers for extremely high delivery pressure in the volute 3|, where greater leakage might be expected, and where such leakage might be greater than the capacity of the control valves in the separator chamber 42.

Fig. 6 illustrates an alternative method of controlling pressures in the chamber 34. In this', method, the connection 40 is supplied with a relief valve 49, which is effective to relieve the chamber 34 through the connection 49. As a variation, the relief valve 49 may be located to relieve the chamber 34 in lieu of the relief ori- When the relief valve 49 is used, as indicated in Fig. 6, then the orice 33 should be enlarged to the point where it ceases to effect any material restriction in flow from the annular cham-4 ber 32 to the chamber 34. The pressure maintained in the chamber 34, and hence in the annular chamber 32, would be regulated by the relieving action of the spring controlled valve set-up 49. One advantage in the use. of the valve 49 resides in the fact that this valve may be a typical automobile tire valve, which can be used on very small pumps. Of course, it is not essential that this particular valve be used, as larger valves would be required on larger pumps. Any relief valve arrangement tending to maintain a substantially constant pressure in' the chamber 34, or a special pressure differential, by leaking oi liquid through the relief valve and connection 40 to the low pressure side of the pump, as through the connection 41, may be used. It might be noted that when using such a relief valve as a means of control, the orifice or 4restriction 48 would be eliminated.

As stated above, make-up sealing liquid for the liquid ring pump or gas compressor may be introduced through the orifice 25 (Fig. 3) and strainer l26 by flow of liquid from the liquidl inlet passage I9 into the vacuum pump inlet 23. The orifice 25 will be proportioned to accord with the size of the particular vacuum pump to furnish the required amount of make-up Jiquid necessary for etlicient operation of this type of pump.

It is important that the liquid dischargel from the pump be controlled,.i. e., cut of! at times when otherwise there might be insufllcient liquid supplied to the liquid pump portion of the apparatus, from the receiver I2, not-only jin order that efficient operation of the liquid pump may be maintained, but to prevent any flow of air or gas through the liquid discharge connections, to the supply side of the system, with resultant deleterious effects in the system. To this end, a pilot controlled discharge valve, indicated generally at 50, is interposed inthe discharge or outlet from the liquid pump I5, the valve proper 5| being controlled by a pilot valve 52,in accordance with liquid level in the receiver I2; through the medium of a float 53.

The details of the pilot controlled cut-off or discharge valve 5ll-5I form specifically no part of the instant invention, being the subject matter of a co-pending application, Serial' No. 349,956 i-iled August 2, 1940, in the name of Harold E. Adams. So far as the present disclosures are concerned, various equivalents of the valve 50--5I may be utilized.

But the combination of these two valves as used in a Wet vacuum pumping apparatus, and particularly when same is applied to a heating system, in addition to overcoming faults in present day systems, and effecting the results mentioned above, are tied in with the desirability of maintaining a' pressure in the volute 3l for the proper sealing arrangements of the vacuum pump rotor, by the prevention of pumping air through `the liquid pump discharge.f

The float controlled pilot arrangement 52-53 operates in conjunction with the main float control of the receiver, by means of which the starting and stopping of the pump is effected, and one of its purposes is to so control the discharge valve 5I as to maintain a liquid level, not only in the bottom of the receiver I2, but also in the inlet connections to the liquid pump I5, and in the pump itself. In fact, the pilot valve may be controlled directly by the main control iioat of the apparatus, in the manner illustrated in Fig. 5 and hereinafter described.

The general operation of this part of the apparatus is as follows: -The condensation flowing from the returns F-D will collect in the receiver E. As the liquid level in the receiver rises, say

to the elevation or level (Fig. 2), the float 55, operating through its levervarm 55 and the rockable contact member 51 will act to swing the toggle switch lever 5%8. As shown in Fig. 5, movement of the arm 58 downwardly under influence of the contact member 51 will. operate the toggle 'switch 59 to close the electrical switch contacts 60. The closing of the contacts will start the motor M, which in turn will operate the pumping apparatus to remove water from the receiver I2. l

As soon as the water level has been lowered by this pumping action to any predetermined desired level, e. g., as indicated at 5I, the contact member 62 will engage the toggle switch lever 58 to break the contacts 60, thus disconnecting the motor and causing the motor to stop, under 'normal conditions.

To control the starting and stopping of the motor M under other than normal conditions.

such as when the vacuum in the receiver or in the return system drops to a predetermined value below normal operating conditions, there is provided a vacuum regulator 63. rl'he regulator 63 operating througha toggle switch 6l makes or breaks a circuit through the electric' contacts 65 in `a manner similar to the switch 59-60, and this regulating will cause the closing of the contact 65 when the vacuum in the receiver or returns drops suiiiciently.

, The motor M and pump driven thereby will ation oi the vacuum switch 64-65 through ther vacuum regulator 63 will cause the motor and pump to stop, provided, of course, that the contacts 60 are open at the same time.

This type of parallel control by a vacuum regulator and liquid level actuator are well known today, and it is believed that the operation thereof will, therefore, be Well understood by those skilled in the art. l

Under normal conditions then, the amount of y liquid in the receiver will vary between the levels 6I and 54, the motor being thrown into and out of operation in accordance with the position oi.' the float 55, as additional liquid cornes in to raise the level, orl the action of the centrifugal pump removes the liquid from the receiver.

The lower level 6I, as is obvious, is suiilciently high to always cover the passage I9 leading to the centrifugal pump, and thus will maintain the impeller in a constantly submerged condition.

But assuming, as an example of one condition L tion between the passage or conduit 69 and the discharge line H is completely closed. 'As the valve'opens, it provides a graduated increase in ow from conduit 69 to line H, in proportion to the lift of the valve, caused by the gradual uncovering of the ports in the valve skirt 10.

The closing and opening of the valve assembly is caused by the hydraulic balance or unbalance maintained by a control Aof pressure on the bottom of the piston 1 I, through the operation of the pilot valve 52, and pressure diierences generated `by the centrifugal pump.

The pilot valve 52 is normally held closed on its seat by a light spring 13, and the normal difwhich may exist, that the contacts 65 remain closed because of vacuum conditions in the system, or the vacuum regulator initiates actuation discharge valve is effected by pilot valve 52 and the oat 53, which float is 'disposed to operate the pilot valve 52 at a level just above the uncovering of the pump in the passage I9, such level being indicated at 68.`

As shown in Fig. 2, the outlet or discharge from the pump i5 is through a conduitv 69, past the valve 5I, into a discharge line H, whence the liquid will be delivered tothe boiler or .other appropriate place, as at A, Fig. l..

The valve 5|, in the illustrated embodiment, includes as part of its assembly a ported skirt 16, and a piston 1| rigidly connected by means of the valve stem to the valve proper 5I. Thepiston1| rides in a Aguide cylinder 12 with a tolerable clearance between its exterior and the interior walls of the cylinder. lI *he diameter of the piston. 1| is made greater than the internal diameter of the seat for the valve 5|, for reasons which will appear.

When the valve assembly is closed, the connecferential in pressure created by the centrifugal pump, that would exist between the line 14 which connects the pilot valve 52 to the discharge valve 5I, and the interior oi the receiver I2.` When, however, the level of liquid in the receiver drops to the point indicated at 68, thus lowering the oat 53, an extension of the float rod 15 engages the valve stem 16 of the pilot valve, and the weight of the oat and rod opens the valve. The

weight of the float 53 is only operative to open the valve 52 when the liquid level reaches the minimum low limit 68, which limit is determined by the location of the opening into pump inlet I9. At any higher liquid level than 68, the natural vbuoyancy of the oat removes pressure on the valve stem 16, and the valve 52 is thus maintained in a normally closed position.

Under normal operating conditions when the centrifugal pump is running, a pressure is mainj tained in the discharge conduit 69 that is higher than the pressure in the suction or inlet passage I9, and hence higher than the pressure in the receiver I2. With the pilot valve 52 in its normal closed position, that is, with the liquid level in the receiver above the point 68, there can be no discharge through the line 14, and consequently the pressure on the buttom of the piston 1| will be equalized with that on top of the piston by the natural transmission of liquid lpressure through the clearances provided between the piston 1I and the cylinder walls 12' ,The pressure in the conduit 69, and hence on the under side of the valve 5I, will, of course, be higher than the pressure in the line H when the centrifugal pump is in operation, particularly if the valve 5| is closed or partially closed.

Because of this higher pressure on the under side of the valve 5|, the pressure difference between conduit 69 and discharge line H will, under normal operating conditions, lift the valve 5I and permit a ow into the discharge line H, the amount of ow and the amount of lift depending upon the pressure drop that exists across the valve 5|. Whenever the centrifugal pump is shut down, the pressure in the conduit 69 will immediately drop to a point below the pressure existing in the discharge line H. The immediate tendency for reversal of ow will thus cause a closing of the valve 5|, seating the valve tightly on its seat. In this respect the action of the valve is quite similar toa conventional check valve, except that the actionl is cushioned and thus improved by the snubbing action of the piston 1I in its guide cylinder 12.

Now should the centrifugal pump continue to operate and reduce the level in the receiver to a point below the level 6I, i. e., to the level 68, the piloty valve 52 will open, and with such opening,

a ilow will immediately start past the clearance l between the piston 1I and the guide cylinder, into the under side of the chamber formed by the cylinder 12, and thence through the line 14 to the receiver I2. The size of the opening through the pilot valve assembly 52, past the valve stem 16 is made sufciently great that when the valve 52 is fully opened by the oat 53, liquid leaking through the clearance space past the piston 1| will freely ow into the receiver i2 with a minimum of restriction. The only restriction to this flow is between the piston 1I and the guide cylinder 12.

The opening of the pilot valve 52, therefore, provides for a reduction in pressure against the bottom side of the piston 1I. This reduction in pressure causes an unbalance in pressure between the bottom of the piston 1| and the top side where the full discharge pressure of the centrifugal pump is communicated to it through the conduit 63. This difference in pressure thus causes a downward movement of the valve tending to throttle or close the discharge line H.

It the pilot valve 52 is open wide by a rapid fall of liquid level in the receiver I2, it will cause a large disturbance in the balance of pressure across the piston 1|, and because of the larger diameter ofthe piston over the diameter of the valve seat for the valve 5|, it will overcome the pressure exerted upwardly from the discharge conduit 69, and will thus firmly close the valve 5I on its seat.

In addition to the difference in areas between valve 5| and the piston 1|, a seating spring may be employed between the top of the valve 5I and the top wall of the valve housing 50.

From the foregoing provisions, it will be evi' dent that further pumping of water from the receiver i2 is stopped as soon as the liquid level reaches the point 68, thus preventing reduction of the level to a point where air or gas might be drawn in through the suction or inlet connection I9 to the centrifugal pump. As stated heretofore, this is an important feature because of the fact that if air is discharged through the centrifugal pump, where it will enter the discharge line H, and the boiler A, such air or gas tends to cause corrosion in the piping, and if a mixture of water and air is discharged, it will tend to corrode the boiler shell and tubes, and to put air into the system which is intended to use only steam.

When a wet vacuum apparatus of this'nature is applied to a heating system, the pilot controlled volute 3| would drop to the pressure of the suction side of the pump.

Under this condition, there would bea possibility of liquid in the liquid ring pump leaking past the sealing surface 28, into the annular chamber 32, and thence past the sealing surface 30 into the volute 3|. There would also be the possibility that this volute pressure would approximate atmospheric pressure, and at the same time the boiler pressure might be lower than that of atmosphere, with the result that this sealing liquid would be pumped out along the path just enumerated and pumped into the boiler. Should this occur, it would result eventually in lowering the reserve seal stored in the receiver, and of If it were not for this, that is, if the course if this sealing liquid were pumped out, there would be a failure in the operation of the liquid ring. pump, as well as in the centrifugal pump. The pilot controlled discharge valve, therefore, prevents the centrifugal pump from uncovering its suction, with a subsequent loss of sealing liquid for the vacuum pump, as outlined.

Fig. 5 illustrates a variation in the pilot valve and oat control therefor. In this embodiment, instead of using two floats, one for the main pump control, and the other for the discharge valve control, the main float is utilized to eiiect both controls, In the arrangement shown, the pilot valve 521 is incorporated in the float switch housing, in the path of movement of the float rod 56. An adjustable tapered collar 16 is placed on the stem or rod 58 in position to open the valve 521 shortly after the oat 55 has opened the contacts 60.

In operation, the float 55 will normally operate between the levels 54 and 6|, as heretofore described, `and will open the contact 60 when it reaches the level 6I. However, provision is made for an over travel between the contact member 62 and the switch lever 58, by suitable adjustment of the stop lug 19, such that the float 55 may drop below the level 6I, if the centrifugal pump continues to function through a closure of the contacts 65 in the vacuum regulator.

With this arrangement, the float 55 can drop to the level 68 which, as has been pointed out, is above the suction connection to the centrifugal pump, such that it will be impossible for air to enter the centrifugal pump inlet or suction line, thereby reducing the pressure in the volute 3|. As the water level recedes from 6| to 63, the float will drop further and will exert its weight through the adjustable tapered collar 18 to the valve stem 161, and thus open the valve 521 by the time the water level reaches the minimum lower level 68.

- The opening of the pilot valve in this arrangement will function to control the discharge valve 50-5I in a manner exactly similar to that described in connection with Fig. .2. When the level rises, thus relieving the valve stem 161 from the weight of the float 55, the pressure condition, coupled with the action of the spring 131, will close the pilot valve 521, just as explained'in connection with the valve 52.

The pressure variation between the normal operating point and the shut-off or closed discharge point of a conventional centrifugal pump is not a wide enough variation to .cause any difculties such as building up detrimental pressures within the pump. lThe equalization of the intermediate channel with the separator 42 prevents the building up of unfavorable pressures in this channel even should the discharge characteristic of the centrifugal cover a wider than normal range of pressures.

It is contemplated that other types of liquid pump than the pure centrifugal type may be used in a system such as that herein described, and that the discharge control mechanism will be equally applicable. In some instances, however, particularly ify an impact or scraper type of liquid impeller is utilized, it is within the scope of the invention to use a pilot control valve which would operate the main cut-off valve in the discharge, as a by-pass valve rather than as a' shutoil valve, because of'the different characteristics of the pump. An impact or scraper type of pump requires increased power and almost unlimited pressure build-up when the discharge is completely closed, and` hence the use of the dis- I 25,306,988 f l 7 charge control mechanism in a. by-pass arrangement, as an alternate to the shut-off arrangement, maybe found desirable.

With this arrangement, the main discharge valve, under control of the pilot valve, will be used in exactly the same manner as described heretofore, but instead of closing the discharge, the main valve would open a by-pass which would carry the discharged liquid back to the receiver or suction side of the pump, and the liquid would merely recirculate during the period of time that the pilot valve is opened. This would, therefore, require a main valve similar to the valve organization I4, but reverse acting. The by-pass line would merely be a pipe line extending from the discharge to the receiver, substantially paralleling the control line I8, with an appropriate pressure check valve from the pump chamber.

Another important innovation in the apparatus of Athis invention relates to the organization of the separator 42, and particularlyin the provision for mounting such separator in a much lower relation to the usual position of a separator in this type of apparatus than has heretofore been customary. The usual position of the separator with respect to the receiver and pumping mechanism is illustrated in the Jennings Reissue Patent, No. 15,637, which may be regarded as a typical present day organization.

As an auxiliary, but not necessarily essential I feature, in conjunction with the lowered relationship of the separator to the receiver and pumping mechanism, provision has been made for shutting off the air discharge, should the separator unit for any reason become flooded. In typical present day structures the air discharge separator, not to be confused with the receiver I2, wherein initial separation of gases and liquids from the returns is eiected, is placed at an elevation above the main receiver, or at least, abovethe maximum liquid level that would obtain in the receiver. This arrangement places an additional discharge head equal to the static height, plus friction, above the vacuum pump, and creates a, disadvantage in the vacuum pump, resulting in its lowered efficiency. In accordance with the present invention, the separator is positioned (see Fig. 2), below normal operating levels in the receiver and close to the vacuum pump discharge, thus eliminating a large part of the gas discharge static and friction losses.

In present day structures, this lowered position could not be arranged, because of the possibility of flooding the separator during shut down periods, with a subsequent discharge of the flooding liquid through the air discharge connection upon resumption of operations. Such a discharge to the atmosphere of slugs of water obviously would be objectionable. should the return lines connected to the receiver be close to atmospheric pressure, liquid `would run out of the low air discharge from the separator before such liquid could ll the receiver *o tive., The avoidance of the above difficulties and the lowered position of the separator is obtained in part by the use of a float control valve 80, operating in conjunction with the normal float operated Valve 8|.

[The purpose of the separator 42, in addition to Furthermore, U

charge from the vacuum pump, which pump discharges into the separator. The air and gas which has been removed from the top of the receiver I2 through the connecting passages 22 and 5 23, port cone 20, and pump inlet port 2|, are distor 42. From the passage 84 the gas and any liquid entrained therein are carried through the opening 85 around a baffle wall 94 into the interiorchamber portion of the separator 42, where the liquid drops to the bottom, for discharge through the float controlled valve 8|, from whence it passes into the conduit I9, which is in direct communication with the interior of the receiver I2. Any air or gas in the separator is discharged through the normally open valve 80,

pasta check valve TI into a chamber 86, from whence it is piped to atmosphere through the connection 81.

The liquid dropping to the bottom of the separator chamber 42 will accumulate therein until '25 the level in the chamber exceeds a limit indicated at 88, the valve 8 I, of course, being closed at this time.` Upon. a rise above this level by continued accumulation, they float 89 rises and in so doing, raises the valve 8|, to which it is connected by means of the pivoted rod or stem 98.

This connection releases the liquid into the inlet or vacuum side 'of the apparatus, i. e., to the receiver I2. During the operation of the pumps,

the float 89 adjusts itself to open the valve 8| so as to discharge liquid through this valve at the same rate as the liquid is coming into the separator, thus maintaining a fairly constant low water level just slightly above the limit 88. If the pump has been shut down for a long period 40 of time, and water has accumulated in the receiver to a point approximating the switch operating level 6I of the receiver, the level in the separator 42 may continue to rise, because after the pump has been shut down, there will be no 4.3 pressure differential operating to force the liquid out of the'separator through the valve 8|. But when this liquid has risen to a level, indicated generally at 9| in the separator, the oat 89 operating through its rod 90 and a link 92 will 5U raise the valve 80 until it engages its seat 93,

thus closing off the air discharge line 86-81. '.'fhe closing of this valve is effective to prevent overow or discharge of liquid from the separator chamber' 42 to atmosphere, through the discharge '.5 line.

' As stated above, the valve'80 is a refinement,

not necessarily essential to the operation of the structure, ast other means such as variation in the location of the separator, increase in its size. etc., might be utilized to prevent kiiooding.

Upon the resumption of the operation of the vacuum pump, it will discharge gases into the passage or conduit 84 through the opening 85,

a level high enough to start the motor. The loss g5 around the bam@ Wan 94 into the top 0f the Sep' of condensate in this manner wouldbe prohibiimmediately, the liquid being discharged through the valve 8| to the low pressure side of the apparatus. Liquid-however, cannot be discharged the main or` primary separation which is effectedglnglst the Valve '30 until the float dIOpS sufficiently in the'receiver I2, is to take care'of excess sealto pen this valve, and the valve 88 will remain ing liquid which is contained in the gaseous disclosed when the valve 8| is open, and until such time as the float 89 drops sumciently to reverse arator l2, materially higher than atmosphere,

andl under these conditions the weight ofthe oat 89 may not be suiiicient to open the valve 80, because of the total pressure diierence across this valve. Should this be the case, the liquid level in' the separator will continue to be lowered at an accelerated pace, due to the superior air pressure within the separator chamber 42, and of course the liquid will be passing out through the valve 8| until the liquid level is sufficiently low to uncover the valve opening.

When this occurs, any remaining air or gas compressed in the separator will discharge pastthe valve 8| back into the receiver |2 and create an immediate .lowering of the pressure in the separator 42. This lowering of pressure will, at the same time,4 lower the pressure differential across the valve 8| to a point where the weight ofthe oat will be great enough to overcome the pressure difference and open the valve 80.

Any air or gas remaining in the separator at this time will then be discharged past the valve 80 and the pumps and separator will then continue their normal operation.

The purpose of the check valve ll is to prevent return of air into the low pressure side of the system from the atmospheric discharge connections at all times when gas from within the separator is not being discharged outwardly.

While not essential, nevertheless the operation of the air and gas discharge valve 80, by providing for elimination of the periodic discharge of slugs of water, in the. event that the separator has filled with water during a shut-down period, permits a reduction in size of the separator, a somewhat lower location thereof with respect to the vremainder of the apparatus, and prevents sudden surges of liquid upon starting up of operations.

Reference has been made to the advantages in the vertical position of the pump axes which permits maximum utilization of the liquid storage capacity of the receiver I2 with the corresponding lower elevation of the returns D and free venting of the eye I81 of the liquid impeller |8. By positioning the eye of the impeller up- -wardly instead of downwardly, as in conventional practice, and maintaining it submerged belowthe minimum liquid level 68, the centrifugal pump will always be primed, and there will be no possibility of trapping air or gas bubbles in the eye. If for some unforeseen reason air or gas should reach the eye, the bubbles being lighter than liquid, will pass freely out of the eye andV not be trapped therein.

In keeping with the desire to maintain compactness and close couple the various elements, there is provided a single wall 95 which functions as-the motor end shield and top wall of the liquid pump ,|5. In connection with this single Wall construction there is provided a builtin'mechanical stuiing box seal and close coupled construction, which enables the use of a very short shaft extension on the motor drive shaft beyond the main bearings, thus reducing the possibility of whip in the shaft, with corresponding wear of parts. f

This mechanical seal incorporates the use of 'a completely sealed bearing 96 provided with an tending therefrom. This arrangement prevents contamination of gas in the bearings in the case' of failure of the rotary seal.

'Ihe rotary seal, best shown in Figs. 2 and 4, comprises a headed sleeve 99 fitting the 'extension of shaft Il.

Packing elements |00 surrounding the sleeve portion of the element 99, and a spring |0I, also encircling the sleeve 88, with one end bearing against the head of the element 99, and its other end bearing against the packingelements |00 serve to maintain from a mechanical standpoint a tight seal.

But in addition, it will be noted that in this close coupled construction, the rotary mechanical seal is continually surrounded with liquid in the liquid chamber of the pump I5, the continuous surrounding of the seal with liquid being another function of the pilot operated discharge valve 5|. By providing for the continuous immersion of the seal in this manner, long life and efficient operation are insured as the liquid flowing around the seal continuously carries away any heat generated by friction of rubbing surfaces. Further, the completely enclosed mechanical stumng box and the completely enclosed sealed bearings eliminate two sources of service difficulty, i. e., lubrication of bearings and adjustment of conventional stuffing box packings. Many service troubles are caused by an operator tampering with the stufling box packing unnecessarily, and in over lubrication of ,the bearings when auxiliary lubricating means are supplied.

From the foregoing, the operation of the complete apparatus, which has been explained in detail in connection with each structural feature, will be readily understood. Liquid and gases from the returns of the system will enter the receiver, both gravitationally and under the inintermediate space 91 and a relief opening 98 ex- 75 iiuence of the pumps, and will be separated in the receiver. Liquids, after separation,` will be drawn off by the centrifugal pump which is con. stantly maintained in a submerged condition, to be returned to the boiler or other appropriate place. The discharge valve 5| will insure that the constant submergence of the centrifugal pump is maintained.

Air or gases, after separation in the receiver will be drawn off by the liquid ring vacuum pump or gas compressor and discharged through the separator 42. In the receiver I2 any liquid seal which has been picked up will be separated and returned to the system, the ultimate separated gas and air being discharged to atmosphere.

Control of the pump operation is eilected by the main float 55, and the vacuum regulator 63. Control of the discharge valve 5| is eiected by the pilot valve 52 or 521, and control of the separator valve is effected by its own float mechanism 89.

With these arrangements, extreme compactness is obtained, and the apparatus can be placed at a lower point in the system than in conventional structures, thus obtaining full advantage of the effect of gravity in the system.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A wet vacuum 'pumping apparatus comprising a receiver for liquids and gases, means to pump liquid and gas from said receiver to ultimate points of discharge comprising a liquid pumping chamber and a gas compressing chamber with a common rotor constructed and posiy asoaess tioned to separate said chambers, said rotor having liquid impeller blades in the liquid pumping chamber and blades of the liquid ring type cooperating with a liquid ring in the gas compressing chamber, means for creating a liquid seal between said chambers, and means beyond the discharge from said gas compressing chamber for' separating from discharged gas, sealing liquid entrained therein, and for returning such liquid to said receiver. x

2. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, means to pump liquid and gas -from said receiver to ultimate points of discharge' comprising a liquid pumping chamber and a gas compressing chamber, with a common rotor constructed and positioned to separate said chambers, said rotor having liquid impeller blades in the liquid pumping chamber and gas compressing vanesin the gas compressing chamber, means for creating a liquid seal between said chambers, means in the discharge from said liquid pumping chamber for throttling iiow of liquid therefrom, and means to control the throttling means in accordance with liquid level conditions in said receiver.

3. A wet vacuum pumping 'apparatus comprising a receiver for liquids and gases, means to pump liquid and gas from said receiver to ultimate points of discharge comprising a liquid pumping chamber and a gas compressing charn- ;A

ber, with a common rotor constructed and positioned to separate said chambers, said rotor having liquid impeller blades in the liquid pumping chamber and gas compressing varies in the gas compressing chamber, means for creating a liquid seal between said chambers, and means Ybeyond the discharge from said gas compressing chamber for separating from discharged gas, sealingy liquid entrained therein, and for returning such liquid to said receiver, means in the discharge from said liquid pumping chamber for throttling flow of liquid therefrom, and means to control the throttling means in accordance with liquid level conditions in said receiver.

4. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, unitary, combined means having separate liquid and gas pumping elements to pump liquid and gas from said receiver to ultimate points of discharge,

means in the discharge from said liquid pumping means for throttling iiow of liquid therefrom, and means in said receiver tocontrol the degree of throttling of said discharge in accordance with liquid level in the receiver.

5. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, means to pump liquid and gas from said receiver to ultimate points of discharge including a unitary combined liquid handling and liquid ring type gas handling pump mechanism and means to maintain the inlet to said liquid pumping means at all times submerged thereby to substantially eliminate passage of air through said liquid pumping means. i

6. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, unitary, combined means having separate liquid and gas pumping elements to pump liquid and gas from said receiver to ultimate points of discharge and means controlled by liquid level in said receiver to restrict and throttle discharge from said liq- `uid pumping means in accordance with liquid levels in s'aid receiver, whereby to substantially eliminate passage of air through said liquid pumping means.

7. A wet vacuum pumping apparatus comprise ing a receiver for liquids and gases, unitary, combined means having separate liquids and gas pumping elements tot pump liquid and gas from said receiver to ultimate points of discharge, liquid level actuated means in said receiver to control operation of said liquid and gas pumping means, and means controlled by liquid level in said receiver to restrict and throttle discharge from said liquid pumping means in accordance with liquid levels in said receiver whereby to substantially eliminate passage of air through said liquid. pumping means.

8. A wet v acuum pumping apparatus comprising a receiver for liquids and gases, unitary combined means having separate liquid and vgas pumping elements to pump liquid and gas from said receiver to ultimate points of discharge, liquid level actuated means in said receiver to control operation of said liquid and gas pumping means, vacuum actuated means to additionally control operation of said liquid and gas pumping means, and meansvcontrolled by liquid level in said receiver to restrict and throttle discharge from said liquid pumping means in accordance with liquid levels in said receiver, whereby to substantially eliminate passage of air through said liquid pumping means.

9. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, unitary combined means having separate liquid and gas pumping elements to pump liquid and gas from said receiver to ultimate points of discharge and means controlled by liquid level in said receiver to restrict and throttle discharge from said liquid pumping means in accordance with liquid levels in said receiver, whereby to substantially eliminate passage of air through said liquid pumping means comprising a float controlled pilot valve at the receiver, and adischarge cut- .oi valve means in the discharge from said liquid pumping means, and means connecting said pilot valve and said cut-out valvemeans eiective to provide a control of the cut-01T valve means by said pilot valve.

10. A wet vacuum pumping apparatus comprising a. receiver for liquids and gases, means to pump liquid and gas from said receiver to ultimate points of discharge comprising a liquid pumping chamber and a gas compressing chamber, with a common rotor constructed and posi-- tioned to separate said chambers, said rotor having liquid impeller blades in the liquid pumping chamber and gas compressing vanes in the gas compressing chamber, means for creating a liquid seal between saidchambers, and means in the discharge from said liquid pumping chamber for throttling ow of liquid therefrom, and means in said receiver to control the degree of throttling of said discharge in accordance with liquid level in the receiver.

11. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, means to pump liquid and gas from said receiver to ultimate points of discharge comprising a liquid ing such liquid to said receiver, means in the discharge from said liquid pumping chamber for throttling ilow of liquid therefrom, and means in said receiver to control the degree of throttling of said discharge in accordance with liquid level in the receiver.

12. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, unitary, combined means to pump liquid and gas from said receiver to ultimate points oi' discharge, comprising a liquid pumping chamber, and a liquid ring type gas compressing chamber, means for creating a liquid seal between said chambers eiective to restrict pressure leakage from one chamber into the other, and means beyond the discharge from said gas compressing chamber for separating, from discharged gas, sealing liquid entrained therein, and for returning said liquid to said receiver. y

13. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, unitary,

combined means to pump liquid and gas from said receiver to ultimate points of discharge, comprising a liquid pumping chamber, and a liquid ring type gas compressing chamber, means for creating a liquid seal between said chambers etl'ective to restrict pressure leakage from one chamber into the other, and means beyond the discharge from said gas compressing chamber for separating, from discharged gas, sealing liquid entrained therein, and for returning said liquid to said receiver comprising a separator chamber positioned below the minimum low level of liquid in said receiver. A

14. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, means to pump liquid and gas from said receiver to ultimate points of discharge, comprising a liquid pumping chamber and a gas compressing chamber, means for creating a liquid seal between said chambers eiective to restrict pressure leakage asoaese from one chamber into the other, and means beyond the discharge from said gas compressing chamber for separating, from discharged gas,

sealing liquid entrained therein, and for returning said liquid to said receiver comprising a separator chamber positioned below the minimum low level of liquid in said receiver, and having a liquid discharge valve in communication with the inlet to the liquid pumping means, and a valved gas discharge in communication with atmosphere.

15. A wet'vacuum pumping apparatus comprising a receiver for liquids and gases, means to pump liquid and gas from said receiver to ultimate points of discharge, comprising a liquid pumping chamber and a gas compressing chamber, means for creating a liquid seal between said chambers effective to restrict pressure leakage from one chamber into the other, means beyond the discharge from said gas compressing chamber for separating, from discharged gas, sealing liquid'entrained therein, and for returning said liquid to said receiver comprising a separator chamber positioned below the minimum low levell of liquid in said receiver, and having a liquid discharge valve in communication with the inlet to the liquid pumping means, a valved gas discharge in communication with atmosphere, and a liquid control valve insaid gas discharge enective to close said discharge against liquid ow therethrough.

16. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, means to pump liquid ,and gas from said receiver to 75` having a oat operable at intimate points of discharge. comprising e liquid pumping chamber and a gas compressing chamber, means for creating a liquid seal between said chambers effective to restrict pressure leakage from one chamber into the other, means beyond the discharge from said gas compressing chamber for separating, from discharged gas, sealing liquid entrained therein, and for returning said liquid to said receiver comprising a separator chamber positioned below the minimum low level oi liquid in said receiver, and having a liquid discharge valve in communication with the inlet to the liquid pumping means, a valved gas discharge in communication with atmosphere, a liquid control valve in said gas discharge eiective to close said discharge against liquid ow therethrough, and iloat actuated means in said separator for controlling operation of said liquid discharge valve and said liquid control valve.

17. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, means having separate liquid and gas pumping elements to pump liquid and gas from said receiver to ultimate points of discharge, means controlled by liquid level in said receiver to restrict discharge from said liquid pump means in accordance with l liquid levels in said receiver, whereby to mantain the inlet to said liquid pumping means constantly submerged, comprising a discharge cut-ofi valve means in the discharge from said liquid pumping means, and a pilot valve at the receiver connected to said cut-oil' valve to control operation thereof, and float actuated means operable by liquid level in said receiver to control the operation of said liquid and gas pumping means and to control the operation of said pilot valve.

18. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, means having separate liquid and gas pumping elements to pump liquid and gas from said receiver to ultiymate points of discharge, means controlled by liquid level in said receiver to restrict discharge from said liquid pump means in accordance with liquid levels in said receiver, whereby to mantain the inlet to said liquid pumping means constantly submerged, comprising a discharge cut-oit valve means in the discharge from said liquid pumping means, a pilot valve at the receiver connected to said cut-oil valve to control operation thereof, oat actuated means operable by liquid level in said receiver to` control the operation. of said liquid and gas pumping means and to control the operation of said pilot valve coinprising a iloat in the receiver, and connections therefrom to the driving mechanism for said pumping means, operable at certain levels to start and stop the pumping means, -and said pilot valve lower levels in the receiver, as determined by said ilrst oat to open and close said pilot valve.

19. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, means having separate liquid and gasv pumping elements to pump liquid and gas from said receiver to ultimate points of discharge, means controlledA by liquid levelin said receiver to restrict discharge from said liquid pump means in accordance with liquidlevels in said receiver, whereby to maintain the inlet to said liquid pumping means constantly-submerged, 'comprising a discharge cutoiI valve means in the discharge from said liquid pumping Y means, a pilot valve at the receiver connected to said cut-oit valve to control operation thereof, float actuated means operable by liquid level in said receiver to control the operation of said liquid and gas pumping means and to control the operation of said pilot valve, comprising a float in the receiver, and connections therefrom to the driving mechanism for said pumping means operable atcertain levels to start and stop the pumping means, and means actuatable by said float at lower levels in the receiver to open and close said pilot valve.

20. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, means to pump liquid and gas from said receiver to ultimate 'points of discharge, comprising a liquid pumping chamber, and a gas compressing chamber of the liquid ring type, with a common rotor constructed and positioned to separate said chambers, means including said rotor to seal said chambers against pressure leakage from one to the other, said rotor having centrifugally acting liquid impeller blades and an inlet thereto in the liquid pumping chamber, and gas compressing vanes in the gas compressing chamber, said rotor being disposed for rotation about a substantially vertical axis, with its inlet and centrifugal impeller blades on the upper surface of the rotor.

21. A wet vacuum pumping apparatus comprising a receiver for liquids and gases, means to pump liquid and gas from said `receiver to ultimate points of discharge, comprising a liquid pumping chamber, and a gas compressing chamber of the liquid ring type, with a common rotor constructed and positioned to separate said chambers, means including said rotor to seal said chambers against pressure leakage from one to the other, said rotor having centrifugally acting liquid impeller blades and an inlet thereto in the liquid pumping chamber, gas compressing vanes in the gas compressing chamber, said rotor'being disposed for rotation about a substantially vertical axis, with its inlet and centrifugal impeller blades on the upper surface of the rotor, and means including disposition of said rotor below the minimum low liquid level of the receiver, for maintaining said inlet constantly submerged in liquid.

v22. A pumping apparatus comprising a combined liquid and gas handling pump and a source of liquid supply to the liquid handling side of said pump, said pump having a unitary, combined impeller-rotor mounted for rotation about a substantially vertical axis, with the inlet to the liquid impeller side of the rotor and the liquid impeller blades on the upper surface of the rotor, said rotor having gas compressor vanes on the under surface thereof.

23. A pumping apparatus comprising a combinedliquid and gas handling pump and a source of liquid supply to the liquid handling side oi said pump, said pump having a unitary, combined impeller rotor mounted for rotation about a substantially vertical axis, with the inlet to the liquid impellerv side of the rotor and the liquid impeller blades on the upper surface of the rotor, said rotor having gas compressor vanes on the under surface thereof, means for driving `said rotor including a drive shaft extending along said axis, and la, common wall forming an end shield for the driving means and a casing wall for the pump.

24. A pumping apparatus comprising a combined liquid and gas handling pump and a source of liquid supply to the liquid handling side of impeller-rotor mounted for rotation about a substantially vertical axis, yvith the inlet to the liquid impeller side of theroti" and the liquid impeller blades on the upper surface of the rotor, said rotor having gas compressor vanes on the under surface thereof, means for driving said rotor including a drive shaft extending along said axis, a common wall forming an end shield for the driving means and a casing wall for the pump, a sealed anti-friction .bearing disposed adjacent said common wall, and a mechanical seal adjacent the rotor and extending through said 25. A pumping apparatus comprising a combined liquid and gas handling pump and a source of liquid supply to the liquid handling side of said pump, said pump having a unitary, combined impeller-rotor mounted for rotation about a substantially vertical/axis, with the inlet to the liquid impeller side of the rotor and the liquid impeller blades on the upper surface of the rotor, said rotor having gas compressor venes on the under surface thereof, means for driving said rotor including a drive shaft extending along saidI axis, a common wall forming an end shield for the driving means and a casing wall for the pump, a sealed anti-friction bearing disposed adjacent said common wall, a mechanical seal adjacent the rotor and extending through said wall, said mechanical seal comprising a headed sleeve extending along the shaft into said wall, packing means surrounding said sleeve, and resilient means between said packing means and the head of said sleeve, effective to maintain the packing in sealing engagement with said wall.

v 26. In a wet vacuum pumping apparatus, a receiver for liquids and gases, means to pump liquid and gas from said receiver to ultimate points of discharge, comprising a liquid pumping chamber and a liquid ring type gas compressing chamber, a common rotor formed with a central driving disc positioned to form a partition wall separating said chambers, said disc having liquid impeller blades in the liquid pumping chamber, and gas compressing varies in the gas compressing chamber, means for creating a liquid seal between said chambers and about said rotor, and

means to maintain said seal under pressures approximating discharge pressures of the gas pumping means.

27. A pumping apparatus comprising separate l liquid and gas pumps, a receiver for liquids and gases, a source of supply, said pumps having a said pump, said pump having a unitary, combined unitary rotor and both having their inlets connected to .the source of supply; an impeller rotor mounted for rotation about a substantially vertical axis with the inlet to the impeller and the impeller blades on the upper surface of the rotor, and means controlled by liquid level in the source of supply, automatically operable torestrict discharge from said liquid pump, wherebyy to maintain the inlet to the impeller constantly submerged.

28. A pumping apparatus comprising separate liquid and gas pumps, a receiver for liquids and gases, a source of supply, said pumps having a unitary rotor and both having their inlets connected to the source of supply, an impeller rotor mounted for rotation about a substantially'vertice1 axis with the :met to the impeller and the impeller blades on the upper surface of the rotor, and means, controlled by liquid level in nthe source of supply, to restrict discharge from said liquid pump, for maintaining said inlet and said blades constantly submerged in liquid from said source of supply.

29. A pumping apparatus comprising separate liquid and gas pumps, a receiver for liquids and gases, a lsource of supply, said pumps having a unitary rotor and both having their inlets connected to the source oi supply. an impeller rotor mounted for rotation about a substantially vertical axis with the inlet to the impeller and the impeller blades on the upper surface of the rotor,

vdriving means and a casing wall for the pump.

30. A pumping apparatus comprising separate liquid and gas pumps, a receiver for liquids and gases, a source of supply, said pumps having a unitary rotor and both having their inlets connected tothe source of supply, an impeller rotor mounted for rotation about a substantially vertical axis with the inlet to the impeller and the impeller blades on the upper surface of the rotor, and means for driving said rotor including a drive shaft extending along said axis, a common wall forming-an end shield for the driving means and a casing wall for the pump, a sealed anti- Iriction bearing disposed adjacent said common wall, and a mechanical seal adjacent the rotor and extending through said wall.

31. A pumping apparatus comprising separate liquid and gas pumps, a receiver for liquids and gases, a source of supply, said pumps having a unitary rotor and both having their inlets connected to the source of supply, an impeller rotor mounted for rotation about a substantially vertical axis with the inlet to the impeller and` the impeller blades on the upper surface of the rotor, means for driving said rotor including a drive shaft extending along said axis, a common wail forming an end shield for the driving means and a casing wall for the pump, a sealed anti-friction bearing disposed adjacent said common wall, a mechanical seal adjacent the rotor and extending through said wall, said mechanical seal comprising a headed sleeve extending along the shaft into said wall, packing means surrounding said sleeve, and resilient means between said packing means and the head of said sleeve, effective to maintain the packing in sealing engagement with said wall.

32. A pumping apparatus comprising separate liquid and gas pumps, a receiver for liquids and gases, a source of supply, said pumps having a unitary rotor and both having their inlets connected to the source of supply, an impeller rotor mounted for rotation about a substantially vertical axis, with the inlet to the impeller extending upwardly in the direction of said axis, said impeller and inlet being positioned below the normal low level of liquid from said supply, and

` means, controlled by liquid level in the source of supply, automatically operable to restrict discharge from said liquid pump, whereby to maintain the inlet to the impeller constantly submerged.

HAROLD E. ADAMS.

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