US2745254A - Fluid flow controlling device - Google Patents

Description

May 15, 1956 H. MALKOFF 2,745,254

FLUID FLOW CONTROLLING DEVICE Filed June 10, 1954 2 Sheets-Sheet l lNVENTOR May 15, 1956 H. MALKOFF 2,745,254

FLUID FLOW CONTROLLING DEVICE Filed June 10, 1954 2 Sheets-Sheet 2 INVENTOR W s .1

I BY I I I u4 ATTORNEYS United States Patent FLUID FLow CoNTRoLLING DEVICE Hyman Malkotf, Levittown, Pa., assignor to Kramer Trenton Company, Trenton, N. J., a corporation of New Jersey Application June 10, 1954, Serial No. 435,716

7 Claims. (Cl. 62-3) This invention relates to an automatic fluid flow controlling device and is particularly designed and adapted for service in low temperature refrigerating systems which include an arrangement for hot gas defrosting of the evaporator.

An object is to provide such a device which has, in itself, the capacity automatically to permit free flow of fluid in gaseous phase through one path, and alternately, to permit a modulated flow of fluid in liquid phase through a second path.

Another object is to provide such a device which is adapted to be automatically controlled by relative pressure conditions affecting it.

Another object is to provide such a device which is excellently suited to use in the low side of refrigerating 130 temperature, low powered compressors of either the open or hermetically sealed type.

Another object is to provide such a device which will' serve as a pressure controlling or limiting valve to prevent overloading and stoppage of the compressor motor due to excessive crank case pressure; and will also act as a pressure reducing or expansion valve to facilitate reevaporation of liquid refrigerant during and immediately following defrosting periods, while maintaining the desired pressure in the compressor crank case, and the least pressure drop in the low side during refrigerating cycles of systems that include a reevaporator in the low side.

Another object is to provide such a device which is adjustable with respect to its functioning so as to be useful in systems designed to meet differing requirements and be capable of automatically fulfilling its intended purposes.

Another object is to provide such a device which is simple in construction, of'low production cost, and yet eflicient, sturdy, and durable in operation.

A further object is to provide certain improvements in the form, construction, and arrangement of the several parts of the device, whereby the above named and other objects inherent in the invention may be effectively attained.

In brief summary, the device comprehends a valve construction having one inlet and two outlets, with spring biased elements that are subject to pressure conditions at the outlet side, whereby fluid in gaseous and liquid phase may be successively received at the inlet, the gaseous phase be permitted either freely to flow through both outlets or be inhibited from flowing, and the liquid phase be permitted to flow through one outlet; the said spring biased elements serving to modulate the flow of the liquid or gaseous phase in order to maintain desired pressure at the outlet side of the device, and also functioning as an expansion valve for the liquid phase. A particular adaptability of the invention is as indicated in the foregoing statement of objects thereof.

A practical embodiment of the invention is represented. in the accompanying drawings in which--- Fig. l exhibits a vertical central section through the. device; and

Fig. 2 represents diagrammatically the installation of the device in the low side of a refrigerating system be tween the evaporator and the reevaporator and compressor.

In refrigerating systems which include compressor, condenser (with separate or combined receiver), evaporator (with the usual expansion valve), and a hot gas defrosting conduit connecting the compressor discharge with the evaporator inlet, there has been a recent trend] to provide the suction conduit, that connects the evaporator outlet and the compressor inlet, with a reevaporator in a branch conduit so that, during refrigerating cycles of the system, the gaseous refrigerant may flow from the evaporator directly to the compressor, while, during defrosting cycles, the liquid refrigerant may flow through the branch conduit and the reevaporator in order to be vaporized before reaching the compressor. In these arrangements a valve has been positioned in the suction conduit to open or close direct communication between the evaporator outlet and the compressor inlet, and 311- other valve has been positioned in the branch conduit to serve as an expansion valve for the liquid refrigerant flowing to the reevaporator. See, for instance U. S. Pat-v ent No. 2,530,440, granted to Otto J. Nussbaum, November 21,1950; and U. S. Patent No. 2,718,764 granted to Israel Kramer September 27, 1955, with particular refer ence to Fig. 3. The device of the present invention is a designed and adapted to replace the functions of both-= the above mentioned previously used valves, and-thereby" notably simplify and reduce the cost of the installation while exhibiting efficiency of a high order. 1 Referring to the drawing, the device comprises a main casing that is denoted generally by 1, although certain parts thereof will receive additional numerals. The inlet is marked 2, and, while shown as having a smooth bore, it may be internally or externally threaded or otherwise fitted for fluid tight reception of the extremity of a conduit such as the suction conduit of a refrigerating system. A main outlet 3 is formed in the side of the casing l opposite the inlet, and a second, or auxiliaryoutlet, marked 4-, traverses the wall of the casing above outlet 3. It is preferably tapered and interiorly threaded. to receive with fluid tight contact the end of a conduit denoted by 5. In the embodiment of the invention shown in the drawing, the auxiliary outlet 4 is of much less cross sectional area than the inlet 2 and outlet- 3, due to the fact that this embodiment is intended for" utilization in a refrigerating system, as previously explained, and the inlet 2 and outlet 3 are designed for the flow of gaseous fluid while the outlet 4 is designed for the flow of fluid in both gaseous and liquid phase; although, in the functioning of a refrigerating system as above indicated, the outlet 4 handles only a minor portion of the total gaseous flow but substantially the entire liquidflow, due to the fact that the specific volume of the gaseous phase is radically higher than that of the liquid phase. The casing 1 is substantially centrally bored to providea: a cylindrical chamber 6, in which is located the hollow' I piston-like head 7 of a poppet type valve, the functional face 8 of which mates with a seat fashioned at the base of the chamber 6. The lower portion of the casing is.

the diaphragm 23.

a function.

fitted in the head 7 and guide piece 10," respectively,

as shown in the drawing.

The 'hea'd 7 'is shouldered at 14, thereby reducing the diameter of the head so'that chamber-6 is in open communication. with inlet 2, While chamber v9 is likewise in open communication with outlet 3. Consequently, it will. be clear that, when the valve face 8 -is raised from its" seat, fluid may pass freely through the casing from inlet 2to outlet3.

Within the casing 1,' and immediately above the chamber 6,is' threaded a hollow cylindrical hood15, the

wall'of which is pierced by a port iii that communicates with the auxiliary outlet 4. The bottom of the hood 15 actually lies within the chamber 6, and its inner peripheral edge serves as a seat for cooperation with the beveled surface 17 'of a plunger valve 18, which rides in the top of the hood '15. The lower extremity of valve 18 is tapered and shouldered to fit the top of a light expansion coil spring 19 which is housed within the valve head 7,

top edge of the casing. The diaphragm is marked 23 and itsperi hery is clamped between the annulus Ztland a casing cover that is indicated generally by 24. The cover embraces the annulus and is shown as secured thereto by=-being flanged thereunder. If preferred, it could be threaded to the circumference of the annulus.

The-upper end of the valve '18 is formed in the shape of "a ball25'that is seated in a socket piece 26 which'has a' fla't upper surface bearing against theunder side of maintaining this contact, but has no other operative A'presser plate 27 rests on the top, of the diaphragm opposed to 'the said socket piece, and is cupped and doubly shouldered to accept the lower ends of two expansion coil springs 28, 29, that are arranged one within'the other, and the upper ends of which are adjustably confined by a screw plug 30 which is threaded into the' top of the cover 24. A cap nut 31 is exteriorly screwed onto the said'cover.

In the side of the valve head 7 adjacent the inlet 2,

V and i below the shoulder 14, is formed a port 32 which Spring 19 serves thevpurpose of.

through conduit 5 faster than it enters through port 32,, and will establish a higher pressure at the latter. This higher pressure, acting on the shoulder 14 of the valve head 7, will lift the latter to open communication between inlet 2 and outlet 3, and the gaseous fluid will pass through both outlets. Reversion of the fluid entering inlet 2 to the liquid phase will permit the parts to return tothe po'sitions-shownin the drawingsgwith a -modulated flow from inlet 2 through outlet 4. It will thus be' evident that-the operationof this device is automatically governed by two pressure differentials, (a)

the differential between the pressure exerted above the diaphragm by springs, 28, 29, and the fluid pressure below the diaphragm; and (b) the ditferenti'al between the fluid pressure above the-valve head 7 and the pressure therebelow acting on shoulder 14. Fluid in both phases may pass through outlet 4, while the flow through outlet 3 is substantially in the gaseous phase only. The result is to control the flow in both the liquid and gaseous phase while at all times maintaining a predetermined i maximum pressure at outlet 4 and its conduit 5.

To treat the operative characteristics of the invention w more specifically, it will be assumed-that the device=is to be installed ina refrigerating system including means for hot gas defrosting of the evaporator as well as means for revaporizingthe liquid refrigerant flowing from evaporator to compressor during defrosting periods as shown, for instance, vin the heretofore named Patent No. 2,530,440, issued November 21, 1950. In such a set-- up, the suction conduit leading from the outlet oftheevaporator willv be directly connected-to the inlet 2; the

' outlet 3 vWill'be directly'connected by a conduit with the inlet of the compressor, while the auxiliary, outlet 4'will 5 be "connected by, its conduit 5 with the inlet of a re-- evaporator, the outlet of which latter will be connected Withthe above named conduit that leads to the-compressor inlet. No valve other than the device of this invention is required in the system between the outlet of the evaporator and the inlet of the compressor;

Fig. 2 diagrammatically illustrates the arrangement just mentioned in which the figure ofsaid- Nussbaum Patent 2,530,440 is changed to substitute the device of the present application for the valves 18 and 19 of the Nussbaum patent; certain other details of the figure of the patent being omitted for clarity. In this Figurel. the'compressor is marked 33 and its discharge is' connected by a conduit 34 with the condenser 35 that'leads into the "receiver 36,. which latter is connected through the conduit '37, heat exchanger 38, and'therrnostatic, expansion valve 39, with the evaporator rib. The outlet of the evaporator is connected by suction conduit 41' with" inlet2 of the device of this invention, and the outlet 3 of the saidvdevice-is connected through conand'regardless of the particular environment, it Will be clear-that any pressure condition in the conduit 5 will also existat the underside of the diaphragm 23, because there is an open passage therebetweenthrough the outlet and'aperture 22; Thus when the said pressure is less than 'the power of springs 28, 29,, the diaphragm will be depressed and will force'valve 18 downwardly to unseatits surface 17 from the inner rimof hood 15. Thi's istheposition of the parts illustrated in the drawing,- and it will be seen that flow through the casingv is place due to the fact that the area of the opening between valve 17, 18, and hood 15 is greater than the area of port- 325: This-wilhpermit the gas orvapor to flow outwardly duits 42 and 43 'with theintake of the compressor. Outlet-4 of the device is connected by its conduit 5, shown in-Fig. 1,' with the inlet of a reevaporator 44, the outlet of-"whichis connected by conduit 45 with conduit .43. A defrosting conduit 46 leads from the compressor discharge to the evaporator and is governed by a solenoidvalve 47. A hand valve' 48 is also inserted in the defrosting conduit for service purposes; while a .drainpipe49 is providedfor disposal of the water of defrosting to the sewer or to any suitable point, the said drainpipe being connected with the-evaporator drip pan (not shown);

With the foregoing arrangement during refrigerating cycles, the gaseous refrigerant willfflow from the evap orator through inlet 2 and from outlet 3 directly'tothe compressor, because, as above-explained, the gaspressure on shoulder 14 willlift valve-face 8 from its seat to opencommunication between inlet 2 and outlet 3. Flow will also pass from the inlet through outlet 4 and conduit-5" to-the reevaporator and, thence, to the compressor. The initiation of a defrosting ,cyclewill'alter the-pressuredif ferential affecting the valve head 7 and cause it to seat with closure of communication between inlet 2 and outlet 3. The refrigerant flow, now at least largely in the liquid phase, will be through the casing 1 from inlet 2 to outlet 4 and its conduit 5, through which latter the liquid will pass to be revaporized in the reevaporator to which conduit 5 is assumed to be connected, as above explained. The complementary functioning of pressure conditions in the conduit 5 and bias of springs 28, 29, will modulate this flow with more or less restriction with the result of (a) preventing too high compressor crank case pressure, (17) maintaining suflicient crank case pressure for adequate compressor capacity, and (c) reducing the pressure of and expanding the liquid to aid its revaporization in the reevaporator. In other Words, the device thus serves as a pressure limiting valve to insure against excessive crank case pressure which might overload and stop the compressor motor; while also serving as an expansion valve during defrosting cycles to facilitate reevaporation of the refrigerant and maintenance of a limited but sufficient pressure in the compressor crank case.

The outlet pressure condition to which the device is responsive can be varied by adjustment of the screw plug 30 which determines the force exerted by the springs 28, 29; and it will be evident that a single spring could be substituted for the said two if desired.

Reference has been hereinabove made to the area of the opening between valve 17, 18, and hood 15, as compared with the area of port 32; and it has been pointed out that, when the refrigerant flow is mainly in the liquid phase, valve head 7 will be seated to close passageway from inlet 2 to outlet 3, while the transformation to flow that is mainly in the gaseous phase will raise the pressure at port 32, which pressure, acting on shoulder 14, will unseat valve head 7. Thus, it may be said that the sizing of port 32 lends to this device a discriminating function which is wedded to the fact that, as also previously mentioned, the specific volume of the gaseous phase is much higher than that of the liquid phase, with the result that the friction drop accompanying the flow of a given mass of liquid refrigerant through port 32 will be insufficient to raise the valve head 7 from its seat, while the friction drop accompanying the flow of :1 corresponding mass of gaseous refrigerant through the said port will so alter the pressure differential above and below the head 7 as to lift it from its seat.

In the drawing there is shown, and in the specification there is described, a single casing encompassing all the parts, but it should be noted that the casing could be divided into a plurality of sections, e. g., one housing the valve 7, 8, with associated parts, and the other housing valve 17, 18, with associated parts; the two sections being connected by a tube or pipe. Therefore, when, in the claims the word casing is employed, the intended meaning is to include structure which houses the parts, whether it be a single enclosure or one composed of a plurality of sections.

I desire it to be understood that various changes may be made in the form, construction, and arrangement of the several parts without departing from the spirit or scope of the invention; and hence I do not intend to be limited to details herein shown or described, except as they may be included in the claims or be required by disclosures of the prior art.

What I claim is:

1. An automatic fluid flow controlling device of the character described comprising, a casing, an inlet thereinto, a plurality of outlets therefrom, and means within the casing governed by relative pressure conditions at the inlet and at least one outlet for opening and closing fluid passageway from the inlet to one of the outlets and modulating fluid passageway to another outlet, the said means for opening and closing fluid passageway to one of the outlets including a valve directly governed by differential pressure, and said means for modulating fluid passageway to another outlet including a valve actuated by diaphragm that is governed by differential pressure.

2. A device as defined in claim 1, in which the valve for opening and closing fluid passageway is governed by fluid pressure, and the diaphragm is governed by mechanical and fluid pressure.

3. An automatic fluid flow controlling device of the character described comprising, a casing, an inlet thereinto, two outlets therefrom, and means within the casing for at one time opening fluid passageway from the inlet to one of the outlets only and at another time opening fluid passageway from the inlet to both of the outlets, said means including a flow restricting orifice between the inlet and one of the outlets of such size as to operatively alter the friction pressure drop of flow therethrough in response to the change of phase from liquid to gaseous and from gaseous to liquid, the said orifice being in communication with the inlet, and the opening of fluid passageway to one outlet only being in response to flow in liquid phase through said orifice while the opening of fluid passageway to both outlets is in response to flow in gaseous phase through said orifice.

4. A refrigerating system including a compressor, condenser, evaporator and reevaporator all operatively interconnected, together with a hot gas conduit connecting compressor discharge with evaporator, and a valve device positioned between the evaporator and the reevaporator and compressor, said device comprising a casing, an inlet thereinto connected with the outlet of the evaporator, an outlet from the casing connected to the inlet of the compressor, a second outlet from the casing connected to the inlet of the reevaporator, and means within the casing for controlling refrigerant flow therethrough from the inlet to both outlets or only to the last named outlet according to whether the refrigerating system is operating on a refrigerating cycle in which the flow is mainly in gaseous phase or a defrosting cycle in which the flow is mainly in liquid phase.

5. A refrigerating system as defined in claim 4, in which the means within the casing of the valve device is subject to pressure conditions in the low side of the system and is constructed and arranged to permit free flow of gaseous refrigerant through the casing from its inlet to the outlet that is connected with the inlet of the compressor during refrigerating cycles of the system and modulated flow of liquid refrigerant through the casing from its inlet to the second outlet that is connected with the reevaporator during defrosting cycles of the system.

6. A system as defined in claim 5, in which the means for permitting modulated flow of liquid refrigerant is also adapted to function as an expansion valve for cooperation with the reevaporator during defrosting cycles.

7. A system as defined in claim 6, in which the means permitting free gaseous flow is governed by differential fluid pressure, and the means permitting modulated liquid flow is governed by difierential pressure that is partly fluid and partly spring generated.

References Cited in the file of this patent UNITED STATES PATENTS 1,737,428 Mercur Nov. 20, 1929 2,248,354 Iaworuwski July 8, 1941 2,496,577 Cahill Feb. 7, 1950 2,530,440 Nussbaum Nov. 21, 1950 2,632,303 Smith Mar. 24, 1953 2,658,357 Smith Nov. 10, 1953 2,718,764 Kramer Sept. 27, 1955

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