US2321609A - Rotary pump - Google Patents

Description

June 15, 1943. J. MARCO 2,321,609

ROTARY PUMP Filed Dec. 16, 1958 9 Sheets-Sheet l June 15, 1943. J. MARCO 2,321,609

ROTARY PUMP Filed Dec. 16, 1939 9 SheetsSheet 2 J. MARCO ROTARY PUMP Jun 15, 1943.

9 Sheets-Sheet 3 Filed Dec. 16, 1939 June 15, 1943. MARCO 2,321,609

ROTARY PUMP Filed Dec. 16, 1939 9 Sheets-Sheet 4 Ill! J. MARCO ROTARY PUMP June 15, 1943.

9 Sheets-Sheet 5 Filed Dec. 16, 1939 June 15, 1943. J. MARCO ROTARY PUMP Filed Dec. 16, 1959 9 Sheets-Sheet 6 June 15, 1943. MARCO 2,321,609

ROTARY PUMP Filed Dec. 16, 1939 9 Sheets-Sheet '7 J. MARCO ROTARY PUMP June 15, 1943.

Filed Dec. 16, 1939 9 Sheets-Sheet 8 J1 vim-14km JO marco alto: 4/1

J. MARCO ROTARY PUMP June 15, 1943.

Filed Dec. 16, 1939 9 Sheets-Sheet 9 Patented June 15, 1943 ROTARY PUMP John Marco, Philadelphia, Pa., assignor to Marco Company, Philadelphia, Pa., a corporation of Pennsylvania Application December 16, 1939, Serial No. 309,661

Claims.

My invention relates to new and useful immovements in pumps and more particularly to a pump of the rotary type and one of the principal objects of the invention is to provide a pump which is so constructed that substantially each and every part and elementthereof may be quickly and readily removed for cleansing purposes and quickly assembled, whereby the device may be used in all industries where sanitary laws are restricted although the device is not limited to such industries.

A further object of the invention resides in the provision of a rotary pump structure which is in part a division of my copending application Serial No. 235,509, and an improvement upon the subject matter disclosed therein.

Still another object of the invention resides in the provision of an improved type of rotor formed with annular and radial grooves for the reception therein on both sides of said rotor of material under pressure which is being treated, so that said rotor may be balanced properly between the elements contacting the same and become hydraulically balanced, the said grooves constituting a self-evacuating means for the material contained therein.

Still another object of the invention resides in the provision of a pair of seal plates between which is carried an improved type of sanitary seal, so constructed and supported in position as to become more effective for sealing, as the pressure increases.

A further object of the invention resides in the provision of improved seals which are self-compensating to wear employing no threads and requiring no manual adjustments.

A still further object of the invention resides in the provision of an automatic compensator wear control plate for taking up wear and maintaining higher volumetric efliciency in the pump.

A still further object of the invention resides in so constructing the rotors as to be'hydraulically balanced by the material being treated and designed to evacuate material after each revolution of said rotors to prevent discoloration, or off-flavoring or scorching of the materials being processed.

A still further object resides in the provision of a manually operated side compensator wear control for adjusting peripheral wear on the rotors in the pump.

A further object of .the invention resides in the provision of a gage diaphragm integrally formed with the pump face whereby pressures within said pump may be transmitted to a gage'head,

said diaphragm being so constructed and arranged as to become a fixed portion of the pump, requiring no removal for cleansing purposes.

A still further object of the invention resides in th provision of shafts for the rotors supported in removable hubs so that the portions of the shaft which contact the materials being pumped through the machine may be readily disassembled and cleansed.

A further object of the invention resides in the provision of seal plates wherein means are formed to detect readily the seepage from or failure of any seal.

A still further object resides in the provision of an improved header plate for the pump with balancing grooves therein cooperating with the grooves of the rotors and automatic compensator wear control plate and also provided with means for the collection of any seepage from the flow of material in the shaft openings therein to be drawn back into the pump at the side thereof by its Own vacuum through grooves which are provided on the opposite face thereof.

Still another object resides in providing a form of shafting consisting of tubular housings with removable solid shafts splined thereto, so that the parts may be readily and easily removed for cleansing purposes.

A still further object resides in providing a pump structure which is comparatively simple in construction, inexpensive to manufacture and one which will be very efliclent in operation, both as to results attained in building up pressures and in its simplicity and readiness for disassembly for cleansing purposes or interchange of parts.

With these and numerous other objects in view, my invention consists in the novel features of construction, combination and arrangement of parts, as will be hereinafter referred to and more particularly pointed out in the specification and claims.

In the accompanying drawings. forming a part of this application Figure 1 is a side elevation of a machine embodying my new pump structure;

Figure 2 is a front elevation thereof;

Figure 3 is an enlarged vertical section as seen on the line 33 of Figure 2;

Figure 3A is a rear. elevation of the pump with the cover plate removed;

Figure 4 is an enlarged fragmentary elevation of the header plate showing therein particularly the gage diaphragm in the rear of said plate,

portions of the rotors being also illustrated through the opening in said header plate;

Figure 5 is a vertical section as seen on the line 55 of Figure 4;

Figure 6 is a side elevation of my pump structure with the homogenizer structure removed and with inlet and outlet parts illustrated;

Figure 7 is an elevation of one of the seal plates;

Figure 8 is a similar view of a companion seal plate;

Figure 9 is a vertical section through the seal plates arranged in abutting relation, with the seals removed;

Figure 10 is an enlarged elevation of one of the seal plates showing the telltale grooves in dotted lines;

Figure 11 is a similar view of the opposite face of the same seal plate showing the telltale grooves in full lines;

Figure 12 is a vertical section as seen on line I2l2 of Figure 11;

Figure 13 is an elevation of the armor which houses the seal gland;

Figure 14 is a vertical section therethrough as seen on the line Il-H of Figure 13;

Figure 15 is an elevation of the seal gland:

Figure 16 is an edge elevation partly in section of said gland;

Figure 17 is a fragmentary section through the seal plates showing the metal armor and seal gland interposed therebetween;

Figure 18 is an elevation of the automatic compensator wear control plate;

Figure 19 is a vertical section therethrough as seen on the line |9l9 of Figure 18;

Figure 20 is an elevation partly in section of the rotor housing illustrating the rotors therein;

Figure 21 is an elevation of the pump or header plate;

Figure 22 is a vertical section therethrough as seen on the line 22--22 of Figure 21;

Figure 23 is an elevation of the rotors removed;

Figure 24 is a horizontal section through one of the rotors as seen on line 24-2l of Figure 23.

Figure 25 is a fragmentary elevation of the front of the machine showing the side compensator adjustment.

Figure 26 is a side elevation thereof.

Figure 27 is a vertical section, partly in elevation, of a modified form of pump structure illustrating a modified form of seal and removable hubs or shafts.

Figure 28 is an elevation of the seal plate such as shown in Figure 8, illustrating the opposite face thereof.

Figure 29 is a vertical section therethrough as Seen on the line 2929 of Figure 28.

Figure 30 is an elevation partly in section of one of the removable hubs used in connection with the modified form of the invention shown in Figure 27.

Figure 31 is an end elevation thereof partly in section.

Figure 32 is an opposite end elevation of said hub.

Figure 33 is an elevation partly in section of the shaft used in connection with the removable hub, the hub being removed.

Figure 34 is a vertical section through a further modification of shafting, illustrating particularly the tubular housing for a removable shaft.

. 26 degrees, as shown at Figure 36 is an elevation of a removable shaft I adapted to be used with the tubular housing i1- lustrated in Figure 34.

Figure 37 is an end elevation of the shaft as shown in Figure 36 illustrating particularly the spline.

Figure 38 shows a vertical section through a tubularshafting adapted to be used in connection with the shaft shown in Figure 36; and

Figure 39 is an end elevation of the latter.

In describing my invention I shall refer to the drawings in which simple reference characters designate corresponding figures throughout the several views and in which I designates a housing of convenient size and shape to accommodate my improved pump structure and the driving means therefor, there being illustrated in dotted lines of Figure 1 of the drawings a motor adapted for use in connection with driving the pump which constitutes, together with the adjunctive elements, the essential feature of this invention. Since my improved pump structure is particularly adapted for use in cooperation with a homogenizer, such as set forth in my copending applications Serial Numbers 235,509, 271,785, 271,786, 287,422, and 287,423, I have illustrated rather diagrammatically and for convenience a type of homogenizer in the drawings in association with the pump structure which I have designated generally by the numeral 2.

As shown, the homogenizer is secured in place to the pump structure through the medium of the bolts 3 and the cover plate 4, as particularly well illustrated in Figure 3 of the drawings. Immediately in the rear of the cover plate 4 there is arranged a header plate 5, against the rear face of which abuts the forward ends of the forward faces of a pair of rotors 6 and I which are respectively splined to the forward ends of the driving shaft 8 and the driven shaft 9. The header plate 5 is provided with a pair of bores III which are arranged concentrically with respect to the axes of the shafts 8 and 9 for the purpose of collecting any seepage of the material being treated that may by-pass to this point. Surroundin the rotors 6 and I is a rotor housing II and immediately in the rear of the rotors abutting the rear face of the rotor housing II is an automatic compensator wear control plate I2 to the rear face of which is applied in abutting relation the front seal plate l3 which cooperates with a companion rear seal plate H. The automatic compensator wear control plate, and both seal plates, as well as the header plate and the rotor housing, are held in position with respect to one another through the medium of the bolts 3 which in turn secures the'same in proper position to the forward end of the pump housing As indicated in the objects of the invention, an improved and essential feature of this invention resides in the seals utilized in association with the seal plates. The inner opposed faces of the respective seal plates l3 and I4 are provided with tapered chambers I6 surrounding the bores I 6 therein, as best illustrated in Figures 3, 8 and 9 of the drawings, for the purpose of housing a metal armor l1 and a seal gland Ill. The seal gland I 8 is annularand has the opposite faces thereof tapered to an angle of approximately I9 which taper or inclination corresponds to a similar taper formed in the chambers i6, whereas the metal armor which of the difference in the angularity of the faces of the seal glands and their respective armors, these elements when brought together through larly set forth, such pressures will be applied to the front faces of the armor, thus applying increased pressure to the seals and obviously, therefore, as the wear takes place in said seals, same will automatically be compensated for,

The rear face of the rear seal plate I4 is provided with eccentric counter-bores 2| which connect with passageways 22, the respective passageways leading in opposite directions for the purpose of detecting seal failure, it being obvious that the opposite arrangement of the passageways 22 will permit of readily detecting which of the two seals may be leaking. In Figures '7 and I have shown these eccentric bores and passageways in dotted lines, whereas in Figures 11 and 12 the same is shown in full lines.

The shafts 8 and 3 extend through the housing l5 and have mounted thereon the auxiliary driving gears-23 which mesh one with the other and said shafts are supported in the bearings 24. Secured to the rear end of the pump body is the gear housing 25 to which in turn is secured the bearing adjusting blocks 26 which are provided with water jackets so as to control frictional temperature rise .50 as not to destroy the lubricant qualities. I

The lower auxiliary gear 23 carried on the shaft 3 picks up the lubricant through the depressed portion of the teeth of said gear and at the point where the teeth of the two gears enter into enmeshment there is provided within the pump body a tapered passageway 21 in the upper shaft bore extending downwardly toward the rear end of the body and terminating in a plane slightly below the point at which the teeth of the two gears enter into enmeshment. At this point there takes place a pump action driving the oil forwardly to the front bearings of the upper shafts through this tapered enlargement 21 of the bore. At the lower end of the pump housing, as illustrated in Fig. 27, there is provided an oil sump 28. This sump constitutes a means for the collection of the condensation resulting from the oil as it is circulated through the pump body and a drain 29 is provided at the lower end of said sump for the removal at desired intervals of this condensation. Leading from the upper portion of the sump is a passageway 30 which extends rearwards toward the auxiliary gear 23 of the lower shaft 60. Thus, the lubricant which is freed of its condensation is permitted to circulate freely through said passageway 30.

At the extreme rear end of the shaft 8 is provided a gear 3| over which extends the chain 32, the latter being also trained over the pinion 33 carried on the shaft of the motor 34, as best illustrated in Figure'3A of the drawings.

10 the abutment or compression of the seal plates I v of a connector groove ll.

' As previously described, this pump structure is particularly adapted for use in association-with an homogenizer, but, of course, not limited to such adaptation. However, since it-is so illustrated in the drawings, and best adapted for use in association with such a device, I have shown the inlet 35 and the outlet 36 as leading to and from, respectively, the housing for the homogenizer, as clearly illustrated in Figures 1 and 2 of the drawings. Of course. it is understood that this inlet and outlet for the material treated in this pump may be located at any ,convenient position on the machine and in Figure 6 of the drawings I have illustrated another form of inlet and outlet.

As the material to be treated in the pump enters the housing, same is drawn therein by the vacuum which is created by means of the rotation of the rotors 6 and 1. These rotors are of a special construction having involuted teeth adapted for enmeshment and constructed to operate at a 25 degree pressure angle. Surrounding the bore of each rotor is a concentric groove 31 and intersecting the same are a plurality of radial grooves 38, one for each tooth of the rotor, each radial groove terminating in a hemispherical recess 39 which is short of the peripheral edge of the tooth by a reasonable distance. These grooves 31, 33 and 33 are formed on both faces of each rotor 6 and I, as best illustrated in Figures 3, 20 and 23 of the drawings.

The rear face of the header plate 5 abuttin the rotors 6 and l is provided with concentric grooves 40 surrounding the bores III which communicate with one another through the medium These grooves 40 are of the same diameter and depth as the grooves 31 in the rotors and are adapted to register therewith. The plate 5 is also provided with the two openings 42 and 43 which may be said to be respectively inlet and outlet openings. 0n the one face of the header plate diagonal feeder grooves 4| lead from the outlet opening 43 respectively to the two concentric grooves 40 and on the opposite face of said plate 5 there is provided, as shown in dotted lines in Figure 21, a pair of evacuating grooves 45 leading, from the inlet opening 42 respectively to the bores Ill.

As stated previously, the rear faces of the rotors 6 and l abut and automatic compensator wear control plate l2. This plate I2 is also provided with concentric grooves 46 surrounding the bores therein of a diameter and depth similar to the corresponding grooves 31 in the rotors and grooves 40 of the header plate. Likewise, this automatic compensator wear control plate I2 is provided with a connector groove ll forming a means of communication between the grooves 46. similar to the groove ll in the header plate 5. The automatic compensator wear control plate l2 also is provided with a third bore 43 which communicates with the grooves 46 through the mediumof feeder grooves 49 similar to the feeder grooves of the plate 5. a.

As the pump operates to rotate the rotors in the direction of the arrows. as shown in Figure 20, a pressure is built up within the rotor housing within the area as shaded and best illustrated in Figure 20, which it will be noted continues toward the outlet side of the housing to the point of enmeshment of the teeth of the two rotors, which is at a point substantially at the median line of the pump. As the pressure is developed in the housing, as shown, the same and equal pressure will be applied to all grooves both concentric and radial of the header plate, rotors and automatic compensator wear control plate and the front face of t he forward seal plate I, abutting the rear face of the automatic compensator plate I2, is provided with a counterbore II as more clearly illustrated in Figures 28 and 29 of the drawings. A slight clearance between shafts 8 and 9 and the bores of the wear control plate l2 and forward seal plate l3 permits a portion of the material under pressure from the rotors to pass to the rear face of said wear control plate and to the counterbored front face of said forward seal plate, thereby substantially cushioning the wear control plate between said rotors and the aforesaid seal plate. As the pressure on seal plate i3 is increased, the seal glands l8 will, obviously, become more effective through the action of armored coverings l9 thereof under pressure.

On the rear face of the automatic compensator wear control plate beyond the point at which the compensator plate is held under compression between the rotor housing and the forward seal plate, the same pressure over the full area exists as in the pressure side of the pump, for the reason that the concentric pressure grooves on the forward side of the automatic compensator wear control plate and the adjacent grooves of the rotors and the similar grooves on the header plate serve to resist the pressure existing on the rear face of said automatic compensator wear control plate, thus eliminating the possibility of the compensator being forced into the rotor faces too severely. Hence, the automatic compensator wear control plate may be said to be substantially floated between cushions of liquid under equal pressure.

As the rotors break enmeshment on the intake side of the chamber enclosed by the rotor housing, approximately one-eighth inch past the vertical median line therethrough, a vacuum is created. It will b noted that on this intake side of the rotor housing, there is no pressure applied to the outer face of the automatic compensator wear control plate, although'there exists a pressure on the rear face of said plate equal to the maximum pressure within the pump. Thus, the vacuum suction at the intak side of the housing, aforesaid, and the pressure referred to causes the automatic compensator wear control plate to be urged toward a position for engagement with the rear faces of the rotors, causing a-slight arcing of said plate at the intake side of the housing which contacts with the rotor faces at points beyond the balancing grooves therein. As a result thereof, both faces of the rotors operate snugly against the adjacent faces of the header plate and the automatic compensator wear control plate, at the intake side of the rotor housing, serving to control the volumetric efficiency. If this were not true there would exist a by-pass from the pressure side of the pump. Obviously, as a result of this arcing of the compensator plate and the snug fit of the rotors, between header and compensator plates at the inlet side of the rotor housing, there will be an indication of slight contact between the rotors and the adjacent faces of header and compensator plates as illustrated by dot and dash lines in Figure 20 of the drawings. In view of the construction heretofore described, including the cushioning of the automatic compensator wear control plate, it will be seen that the takeup in such wear, as may occur, will be entirely automatic.

Referring particularly to Figure 20 of the drawlugs, I show between the two teeth which are about to become enmeshed a shaded portion desig-nated X which is immediately adjacent the pressure section of the rotor housing. By reason of the enmeshment of these teeth, the liquids under pressure between said enmeshing teeth become entrapped and momentarily the pressure of this entrapped liquid is increased noticeably resulting in an increased pressure which causes the liquid to be transmitted to the connector grooves 31 immediately thereunder and thereover which in turn forces all of the liquids already within the grooves to exit through the radial grooves 38 of the rotors into the pressure side of the rotor housing as each tooth enters that portion of the chamber. In this manner, the liquids within the grooves are being constantly evacuated therefrom and said grooves replenished anew.

As shown in Figures 4, 5 and 20, the openings in the automatic compensator wear control plate I 2 and the seal plates I 3 and H are in registration one with the other and formed permanently in the forward wall of the pump body l5 and in registration with the aforesaid'openings in a diaphragm 50 covering a pocket 5| therein. This pocket leads through the medium of a passageway to a connection 52 which in turn leads to a gage (not shown) on the machine. Oil is introduced in this pocket and through the passageway and connection, whereby pressures built up within this pump body may be recorded hydraulically.

I have provided a means for taking up peripheral wear of the rotors within the housing therefor. To this end I have provided a lug 53 which is bolted, as shown in Figure 25, to the periphery of the pump body through the medium of the bolts 54. The outer end of the lug is slightly reduced and provided with a threaded bore through which extends the manually operated adjusting screw 55 the outer end of which is provided with a handle 56. The free end of this screw 55 is, as shown in Figure 26, adapted to abut the one outer edge of the rotor housing I I and it is apparent from this structure that by turning home the screw 55 minute movement of the rotor housing may be accomplished whereby peripheral wear in the teeth of the rotors may be compensated for and any adjustment made in said screw 55 may be locked against casual displacements through the medium of the lock nuts 51.

In Figure 27 I have shown a slight modification of the-invention the principal feature of which is the use and adaptation of removable shaft hubs 58 applied to the forward ends of the shafts 59 and 60 of the pump. These removable shaft hubs 58 are keyed to the shafts 59 and 50, as best illustrated in Figures 27, 30, 31 and 33 of the drawings. In Figure 32 I have shown the end view of one of the removable shaft hubs illustrating the external keyways to accommodate the splines of the rotors adapted to be engaged therewith.

A further modification of the invention is illustrated in Figures 34 to 39, inclusive, wherein I have shown a shaft of tubular design designated by the numeral 6|. The inner periphery of the shaft 6| is provided with splines as shown at 62.

The shaft illustrated in Figure 34 represents a driving shaft. In Figure 38 I have shown a similar shaft 63 which is adapted to be used as the driven shaft in a. pump construction of the type heretofore described.

In Figure 36 I have shown a solid shaft 64 which is adapted to be introduced through one end of the shaft 6!, the one end of which is pro vided with keyways for engagement with the splines 82. Just as is true of the tubular shaft 6|, shown in Figures 34 and 35, the shaft 63 shown in Figures 38 and 39 is provided with splines 68 for engagement with keyways formed in the solid shaft and adapted to be introduced therein, although not being shown, the same being similar to the shaft 64.

As stated heretofore, my improved pump structure, as hereinbefore described, is adapted for use in connection with the various homogenizers, emulsor valves, grinders, and disintegrators illustrated and described in my various copending applications, as aforesaid. However, it may be here stated that in the treatment of the material in the pump herein set forth, preparatory to the action of the homogenizers, emulsor valves, grinders and/or disintegrators, there takes place a first stage of emulsification through the action of the teeth of the rotors, causing the material From the foregoing description of the construe--v tion of my improved pump, the method ofoperation and the application thereof to use will be readily understood and it will be seen that I have provided a simple, comparatively inexpensive and eflicient means for carrying out the various objects of the invention.

While I have particularly described the elements best adapted to perform the functions set forth, it is obvious that various changes in form, proportion and in the minor details of construction may be resorted to without departing from the spirit or sacrificing any of the principles of the invention.

What I claim is:

1. In a pump of the character described, a rotor housing, a front wall for'said housing formed with an inlet and an outlet, a transmission casing back of said rotor housing having a wall at its front end, a partition between the rotor housing and the transmission casing constituting a rear wall for said rotor housing, shafts rotatably mounted in said transmission casing and extending through the partition into said rotor housing, rotors carried by said shafts within the rotor housing and cooperating with each other to force material under pressure out of the rotor housing through the outlet, said partition being formed with an opening communicating with the outlet, the transmission casing being formed with a pocket registering with the opening in the partition and also with a duct leading from the pocket, a pressure gage having an inlet tube communicating with a rear end of said duct, and a diaphragm mounted between the partition and the front wall of the transmission casing and separating the opening from the pocket and adapted to be flexed in response -to variations in pressure within the rotor housing and act upon fluid in the pocket and the tube to actuate the gage.

2. In a pump of the character described, a rotor housing, a front wall for said housing formed with an inlet and an outlet, a transmission casing back of said rotor housing, a partition between the rotor housing and the transmission casing constituting a rear wall for said rotor housing, shafts rotatably mounted in said transmission casing and extending through the partition into said rotor housing, rotors carried by said shafts within the rotor housing and cooperating with each other to force material under pressure out of the rotor housing throughthe outlet said partition-consisting of front and rear seal-plates and a wear control plate betweenthe front seal-plate and the rotor housing, contacting faces of the seal-plates being formed with registering recesses forming packing boxes about the shafts, packing material in said boxes forming tight joints about the shafts, the rear face of the rear seal-plate being formed with annular pockets surrounding the shafts and with chan-- nels leading from the pockets and constituting drain passages for conducting liquid from leaky p kings.

3. In a pump of the character described, a rotor housing, a front wall for said rotor housing having an inlet and an outlet, a transmission casing back of the rotor housing, front and rear seal plates between the rotor housing and the transmission, casing, shafts rotatably mounted in said transmission casing with their front end extending through the seal plates into the rotor housing, rotors carried by said shafts within the rotor housing for forcing material under pressure out through the outlet of the rotor housing, said plates having registering recesses about the shafts forming packing boxes, packing material said casing and extending into said housing,

companion rotors carried by said shafts within the housing, packing mounted between one of the sealing plates being subject to action of material under pressure to compress the packing tightly about the shafts, and the other sealing plate being formed with channels for conducting material from leaky packings to opposite sides of the rotor housing and thus identifying a leaky packing.

5. In a pump of the character described, a rotor having a front wall formed with an inlet and an outlet, a casing back of said housing, a pair of seal plates between the housing and the casing, shafts rotatably mounted in said casing and extending into said housing, companion rotors carried by said shafts within the housing, annular pockets being formed between said plates about shaft-receiving openings, and packings in said pockets about said shafts, one of the sealing plates being subjected to action of material under pressure to compress the packing and form tight seals about the shafts, and the other plate having channels for conducting material from leaking packings to opposite sides of the rotor housing.

6. In a pump of the character described, a rotor housing having a front wall formed with an inlet and an outlet, a casing back of said housing, a pair of seal plates between the housing and the casing, shafts rotatably mounted in said casing and extending into said housing, companion rotors carried by said shafts within the housing, annular pockets being formed between saidplates about shaft-receiving pockets,

packings in said pockets about said shafts, the plates being also formed with a well opening into the rotor housing for receiving material therefrom, conduits for conducting material under pressure from said well to said pockets, the packing being subjected to pressure to form tight seals about the shafts, and other conduits for conducting material from leaky packings to sides of the rotor housing 7. In a pump of the character described, a rotor housing having a front wall formed with an inlet and an outlet, a casing'back of said housing, a pair of seal plates between the housing and the casing, shafts rotatably mounted in said casing and extending into said housing, companion rotors carried by said shafts within the housing, registering recesses being formed in confronting faces of said plates about shaft-receiving pockets, packings in said pockets about said shafts, the plates being also formed with a well opening into the rotor housing for receiving material therefrom, faces of the plates being formed with channels forming conduits for conducting material under pressure to said pockets, the packings being subjected to pressure to form tight seals about the shafts, there being other channels for conducting material from leaky packings and discharging same at opposite sides of said housing, a diaphragm across said well in spaced relation to the inner end thereof to form an inner chamber, and a gage having a tube communicating with the inner chamber for registering pressure as the diaphragm is flexed in response to variations in pressures of material in the well.

8. In a pump of the character described, a rotor housing, a front wall formed separate from the rotor housing, a transmission casing,

sealing plates between the rotor housing and the transmission casing, shafts rotatably mounted in said casing with their forward portions extending through the sealing plates and into the rotor housing, rotors removably carried by front ends of said shafts within the rotor housing, removable means for securing the rotor housing and the sealing plates tightly clamped between the front wall and the transmission casing, said sealing plates having confronting faces formed with packing boxes about the shafts, packing in said boxes, packing in the transmission casing about forward portions of said shafts, and the rear one of said seal plates having its rear face formed with recesses surrounding the shafts and channels leading therefrom to opposite sides of the plate and constituting drains for detecting leaks through packing in the packing boxes.

9. In a pump of the character described, a rotor housing having an inlet and an outlet, a transmission casing, sealing plates between the housing and said casing constituting a partition, shafts rotatably mounted in said casing and extending through said plates into the housing, rotors carried by said shafts within the housing, packings mounted in said plates and disposed about the shafts, means being provided at one side of the partition for conducting material under pressure to the packings for compressing the packings during operation of the pump, and means at the opposite side of the partition for conducting seepage from individual packings and discharging the same at opposite sides of the housing for visually indicating and identifying leaky packings.

10. In a pump of the class described, a pump I housing having front and rear walls and provided with an inlet and an outlet, rotatable shafts extending through said housing, intermeshing gears loosely splined on said shafts and adapted for longitudinal movement thereon as well as tilting angular movement of their transverse medial planes with respect to the axes of said shafts, sealing means on said shafts adjacent the rear wall of said housing and a self-compensating wear control plate interposed between the rotors and the sealing means and having an opening therein, whereby a portion of the material under the outlet pressure from said rotors is permitted to enter between said sealing means and said self-compensating wear control plate, causing flexure of the latter and corresponding movement of the rotors on saidshafts.

11. In a pump of the class described, a pump housing having side walls and provided with an inlet and an outlet, rotatable shafts extending through said housing, intermeshing rotors loosely splined on said shafts and adapted for longitudinal movement on the latter as well as tilting angular movement of the transverse medial planes thereof with respect to the axes of said shafts, a seal plate on said shafts adjacent the one of said side walls of said housing, a selfcompensating wear control plate interposed between said rotors and seal plate having an opening therein, means formed on the front face of said wear control plate communicating with said opening and additional means formed on the forward face of said seal plate cooperating with material under pressure from said rotors to substantially cushion said wear control plate between the rotors and seal plate and cause flexing of said wear control plate and movement of said rotors on the shafts.

12. In a pump of the class described, a pump housing having front and rear walls and provided with an inlet and an outlet, rotatable shafts extending through said housing, intermeshing rotors loosely splined on said shafts and adapted for longitudinal movement thereon as well as tilting angular movement of the transverse medial planes with respect to the axes of said shafts, a seal plate on said shafts adjacent the rear wall of said housing, a self-compensating wear control plate on said shafts interposed between said rotors and seal plate and having an opening therein, the front faces of said wear control plate and seal plate being respectively formed with concentric grooves and counterbores having communication with said opening in said wear control plate, whereby a portion of the material under outlet pressure from said rotors is permitted to enter between said wear control and seal plates, causing flexure of said wear control plate and corresponding movement of the rotors on said shafts.

13. In a pump of the class described, a pump housing having front and rear walls and provided with an inlet and an outlet, rotatable shafts extending through said housing, intermeshing rotors loosely splined on said shafts and adapted for longitudinal movement thereon as well as tilting angular movement of the transverse medial planes with respect to the axes of said shafts, the faces of said rotors being formed with concentric and radial communicating grooves, a seal plate on said shafts adjacent the rear wall of said housing having its front face counterbored, and a self-compensating wear control plate on said shafts interposed between said rotors and seal plate and having an opening therein, the front face of said wear control plate being formed with grooves cooperating with the grooves on said rotors and communicating with said opening in said wear control plate, whereby a portion of the material under outlet pressure from said rotors is permitted to enter between said seal plate and wear control plate, causing fiexure of the latter and corresponding movement of said rotors on said shafts.

14. In a pump of the class described, a pump housing having front and rear walls and provided with an inlet and an outlet, rotatable shafts extended through said housing, the inner face of said front wall of the housing being formed with communicating grooves, intermeshing rotors loosely splined on said shafts and adapted for longitudinal movement thereon as well as tilting angular movement of the transverse medial lanes with respect to the axes of said shafts, the faces of said rotors being formed with concentric and radial grooves, the grooves on one face of said rotors cooperating with the grooves on the inner face of the front wall, a seal plate on said shafts adjacent the rear wall of the housing, and a self-compensating wear control plate on the shafts interposed between said rotors and seal plate and provided with an opening, the front face of said wear control plate being formed with grooves cooperating with the grooves on the adjacent faces of the rotors and leading to the aforesaid opening, whereby a portion of the material under outlet pressure from said rotors is permitted to enter between said seal and wear control plates causing flexure of the latter and corresponding movement of said rotors on said shaft.

15. In a pump of the class described, a pump housing having front and rear walls and provided with an inlet and an outlet, rotatable shafts extended through said housing, the inner face of said front wall of the housing being formed with communicating grooves, intermeshing rotors loosely splined on said shafts and adapted for longitudinal movement thereon as well as tilting angular movement of the transverse medial planes with respect to the axes of said shafts,

the faces of said rotors being formed with concentric and radial grooves, the grooves on one face of' said rotors cooperating with the grooves on the inner face of the front wall, a seal plate on said shafts adjacent the rear wall of the housing having the front face thereof counterbored, and a self-compensating wear control plate on the shafts interposed between said rotors and the front face of said seal plate and provided with an opening, the front face of said wear control plate having grooves formed therein cooperating with the grooves on the adjacent faces of said rotors and leading to the aforesaid opening, whereby a portion of the material under outlet pressure is permitted to enter between said seal and wear control plates, substantially cushioning the latter in position and causing fiexure thereof with corresponding movement of said rotors on said shaft.

JOHN MARCO.

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