US2568123A - Pressure reducing device for refrigerating apparatus - Google Patents

Description

P 1951 H. M. GOLDBERG 2,568,123

PRESSURE REDUCING DEVICE FOR REFRIGERATING APPARATUS Filed July 25, 1950 2 Sheets-Sheet 1 48 FIG.2

as 54 2 58 INVENTOR:

+ l-JERMAN M.GOLDBERG MW awxywwz ATT'YS Sgpt. 18, 1951 PRESSURE REDUCING DEVICE FOR REFRIGERATING APPARATUS Filed July 25, 1950 2 Sheets-Sheet 2 m 5 i 4 '0 so I47 I L I no I:

no me 21' s| lna FIG. 3 I50 s A A "a m INVENTOR. I: ERMAN M .GOLDBERG H. M. GOLDBERG 2,568,123

Patented Sept. 18, i951 PRESSURE REDUCING DEVICE Fort REFRIGERATING APPARATUS Herman M. Goldberg, Chicago, Ill-., assignor to Standard Refrigeration Company, Inc., Chicago, Illa, a corporation of Illinois Application July 25,1950, Serial No. 175,813

1 claim. 1

The present invention relates to refrigeration systems and more particularly to improved means for controlling the flow of refrigerant from the high to the low pressure sides of the system;

This application is a continuation in-partof my copending application, Serial No. 87,815,1iled April 15, 1949, now Patent Number 2,532,019, issued November 28, 1950, for Pressure Reducing Device for Refrigerating Apparatus.

Present day refrigerating systems invariably employ some type of restricting or regulating device for the purpose of controlling the flow of refrigerant through the system from the high pressure condenser or compressor phase thereof to the low pressure expansion phase thereof. Various types of regulating devices in the form of expansion valves have been employed for this purpose as well as the use of so-called capillary tubing. The many valve structures employed are found to be expensive to manufacture and delicate in operation and therefore unreliable, while the capillary tubing frequently becomes clogged due to the accumulation of foreign matter in the refrigerant or due to Settling out of any existing solid particles in the refrigerant "after a prolonged period of disuse of the system. Moreover, conventional, so-called, capillary tubing has an inside diameter that is exceedingly small so that it is difficult, and sometimes impossible, to clean so that replacement thereof is usually the only solution when clogging occurs. Still fur= ther, because of the small internal dimension of such capillary tubing, uniformity of dimension within any given length of tubing is diflicult to attain and precise regulation of the flow of fluid therethrough is a cut-and-try matter. Thus, in the manufacture of refrigerating units, as for example, household refrigerators or the like, on a large scale, a predetermined length of capillary tubing is determined upon by a out-and-try method to best accommodate a particular test unit of given specifications, and thereafter a large number of the capillary tubes or coils are cut from tube stock for installation in an equal number of assembly line units. Because of the nonuniformity in the internal dimensions of the stock tubing, and because of non-uniformity in the bending or coiling operation when the tubing is actually applied to and installed in the various units, varying flow characteristics are attained in the assembled units and unsatisfactory performance in a large percentage of the units may be expected.

The present invention is designed to over- 2 are attendant upon the use of present day restricting devices, particularly upon the use of the so-called capillary tubing, and toward this end it contemplates the provision of a restricting device which embodies the same principle of operation as does ordinary capillary tubing. in

that it affords a relatively long, restricted path of flow for the refrigerant, but which at the same time is capable of disassembly for the purpose or cleaning the various parts thereof to remove any foreign material so that upon reassembly of the parts the original restricted path of flow for the refrigerant may be reestablished.

The provision of a restricting device of the character briefly outlined above being one of the principal objects of the invention, another and equally important object thereof is to provide such a device in which the length of the capillary path for the fluid, and consequently the amount of refrigerant flowing through the device may be adjustably controlled to any desired degree to attain the desired pressure. drop between the high and the low pressure sides of the system, or, in other words, at the cooling coils thereof.

A further disadvantage attendant upon the use of conventional so-called capillary tubing in pressure regulating systems arises where shipping problems are involved. Where new installations in the form of complete assembled refrigerators, as for example, household refrigerators,

deep freeze units and the like, are shipped from the factory to their various destinations, loss of refrigerant frequency occurs at the points of connection or joints at which the capillary tubing is connected to other parts of the closed fluid system. Such loss of fluid due to leakage frequently is a result of vibration or shock arising either in transit or during the process of unpacking of the unit at its destination. Because of such difiiculties, many manufacturers have found it expedient to ship the units to the dis tributors in dry condition while the distributors, in turn, deliver them to the customer in the same condition, relying upon the service or 7 installation worker to supply the necessary refrigerant at the scene of ultimate installation.

Alternatively, in an effort to overcome the above-noted limitation that is attendant upon the manufacture and installation of refrigerating units, some manufacturers have developed a system. Such a procedure has not been entirely satisfactory in actual practice inasmuch as partial disassembly of the system, or at least uncoupling of certain parts thereof is necessary to render the puncturable seal accessible and, before reassembly of the parts can be made, considerable loss of refrigerant may result. Furthermore, manual puncturing of the seal may leave an opening of undetermined size which acts as a restriction to the flow of refrigerant and, ad-- ditionally, such puncturing may lead to the presence of particles of the sealing material or compound within the closed system.

It is therefore another important object of the present invention to provide an improved regulating device of the character briefly outlined above in which the same adjusting means which is employed for varying the length of the fluid path through the device may also be employed to effect complete blocking off of the fluid path at one end thereof so that leakage of the refrigerant from the device is effectively prevented, thus enabling the manufacturer to supply the refrigeration units in filled condition preparatory to instant use thereof at the scene of installation 4 upon completion of a minor adjustment operation on the part of the installation worker or of the purchaser.

Another and related object of the invention is to provide a restricting unit of this character in which the necessary adjustment for placing the installation in immediate service may be made from a convenient point adjacent and. outside of the restricting unit without requiring partial or complete disassembly thereof and by the use of ordinary tools.

A still further object of the present invention is to provide a restricting device having the engineering and physical characteristics of both a restrictor valve as well as of capillary tubing and which may readily constitute a built-in part of an evaporator unit associated with a refrigerating system.

Additional objects of the invention are, in general, the same as those set forth in my above mentioned copending application of which this is a continuation, while still other objects and advantages of the invention, not at this time enumerated will become more readily apparent as the nature of the invention is better understood.

The accompanying two sheets of drawings illustrate two selected embodiments of the invention, and the views thereof are as follows:

Fig. 1 is an elevational view of an evaporator unit embodying one form of the improved refrigerant restrictor device forming a part of the present invention;

Fig. 2 is an enlarged detail longitudinal sectional view taken substantially through the restrictor valve of Fig. 1;

Fig. 3 is a further enlarged detail fragmentary sectional view taken substantially through the inlet end of the restrictor device;

Fig. 4 is a transverse sectional view taken substantially along the line 44 of Fig. 3;

Fig. 5 is an elevational view similar to Fig. 1 of an evaporator unit embodying a modified form of the improved restrictor device comprising the present invention;

Fig. 6 is an enlarged sectional view taken substantially centrally through the restrictor device of Fig. 5;

Fig. 7 is a further enlarged fragmentary sectional view taken substantially centrally through the outlet end of the restrictor device; and

Fig. 8 is a sectional view taken substantially along the line 88 of Fig. '7. I

For the purpose of illustration, the improved restricting device of the present invention, and of which two forms have been illustrated herein, is shown as employed in connection with an evaporator unit, of which it may constitute a built-in part, for regulating the flow of refrigerant from the high side of the system to the low side thereof. In other words, the restricting device, forming the subject matter of this invention, may be used to advantage for controlling the flow of refrigerant from the compressor or condenser phase of the system to the expansion phase thereof.

Referring now to Figs. 1 to 4 inclusive, wherein one form of the invention has been illustrated,

the restricting device is designated in its entirety at If] and may constitute a built-in part of an evaporator unit i2 of more or less conventional design and having associated therewith the usual expansion or refrigeration coil l4 constituting, in part, the low pressure phase of the system. The restricting device I9 is generally of tubular design and has its outlet end connected as indicated at l6 with the refrigeration coil I4, while its inlet end may be connected as indicated at l8 with a tube 29 leading from a compressor or condenser unit (not shown) constituting, in part,

the high pressure phase of the system.

The restrictor device l0 involves in its general organization an elongated tubular body or cylinder 22 having an axially extending main bore 24 which is provided with internal screw threads 28 throughout its entire length. The threads 26 are of V-shape in cross section and provide relatively sharp, deep troughs 28 therebetween and have relatively sharp V-shaped crests 30 (see particularly Fig. 3). The cylinder 22 may have external screw threads 32 at its inlet end to receive thereover the internal threads 34 formed within a cap member 36. The cylinder 22 is formed with a closure wall 38 at its outlet end which has formed integrally therewith an outwardly projecting nipple 40 having an axial bore 42 communicating with the main bore 24 of the cylinder 22. The nipple 40 may be formed with an external friction surface 44 which is adapted to receive thereover the expanded end of the refrigeration coil l4 to provide the fluid tight connection [6.

The V-shaped threads 26 in the valve cylinder 22 are adapted to engage screw threads 46 formed externally on an elongated internal rod 48, which may be positioned within the main bore 24. The threads 46 on the rod 48 are provided with V- shaped troughs 50 therebetween and flat crests 52. The threads 46 may be formed in any suitable manner, as for example by cutting V-shaped threads on the plug and then grinding down the sharp crests thereof to produce the flat crests 52. The interfitting of the flat crests 52 of the threads 46, with the sharp V threads 26 forms a slender spiral capillary passage 54 which is generally triangular in cross section. This passage 54 affords a uniformly restricted passage for the flow of refrigerant as the same progressively flows from the inlet end of the device to the outlet end thereof.

Means are provided for permitting or effecting adjustment of the length of the passage 54 and this means includes a counter-bore 56 which is formed in the inlet end of the cylinder 22, the counter-bore 56 being coaxial with the main bore inder 22 at the inner end of the counter-bore 56 and provides the means for adjusting the length of the spiral passage 54, in that the degree of penetration of the rod #8 within the main bore 2% and beyond the shoulder or step 53 directly determines the amount of restriction oifered to the flow of the refrigerant. The length of the spiral restricting passage 54 increases, therefore, when the rod E3 is threaded into the main bore 24, and decreases when the rod is threaded outwardly from the main bore.

A seal or washer 60 may be positioned between the cap member 36 and the inlet end of the cylinder 22 to provide a fluid tight seal between the cylinder and the cap member.

' The cap member 36 is provided with an axially aligned threaded nipple 62 which projects outwardly therefrom and is adapted to threadedly receive thereover an internally threaded closure cap 64. A passage'fili extending axially through the cap 36 and through the nipple s2 permits insertion of a screw driver or other tool therethrough upon removal of the cap for engagement with a slot El formed in the proximate end of the rod 48. Thus by rotating the threaded rod d8 Within the cylinder 22 in one direction or the other, the length of the spiral restricted passage 54 and, consequently, the flow and pressure drop of the refrigerant fluid passing through the restricting device may be regulated after the system has been placed in operation.

A seal washer "It may surround the nipple 62 'to form a fiuid tight seal between the closure cap 64 and the cap 36 when the former is threaded on the nipple 62.

An inclined passage 12 through which refrigerant may enter the device is formed in the cap member 36. This passage 12 communicates with and extends laterally from the passage 66. The passage 72 may have a suitable screening material M, such as wire gauze, inserted therein for the.

purpose of separating foreign or extraneous matter from the refrigerant before it passes through the restricting device so that the device will not become clogged. The screening material 14 may be removed from the passage 34 from time to time so that it may be cleaned or replaced with new, screening material.

The end of the tube 20 leading from the high pressure stage has communication with the passage !2 and may be joined to the cap member 36 by any suitable means as, for example, by soldering or the like.

The rod 88 may be solid, but it is sometimes desirable that it be of hollow construction and provided with a longitudinally extending bore '16 which is closed at one end and which communicates with the space existing within the cylinder 22 at the outlet end thereof. Thus, the bore 16 and space just referred to constitute, in effect,

-an expansion chamber 78 at the outlet end of the spiral passage 54 which permits the refrigerant fluid to expand to a greater extent than if the .rod as were solid so that the temperature drop of the expanding refrigerant will be appreciably greater. It is not altogether necessary, however, that the rod 48 be provided with the bore 16 as it may be solid, whereby the space or chamber 78 alone may be used for expansion of the refrigerant.

The pressure reducing or restricting device I0 serves as an extremely effective means for controlling the flow of refrigerant entering the expansion coil i l of the evaporator unit l2. Liquid refrigerant under pressure from the usual compressor or condenser of the refrigerant system,

enters the passage 12from the tube 20 and-passes through the screening material 14 where any foreign matter which might be intermixed with the refrigerant is screened or separated therefrom. The liquid refrigerant then flows through the passage 66 and thence into the counter-bore 56 in the cylinder 22. Upon arriving at the shoulder 58 at the inlet end of the counter-bore the refrigerant enters and progresses through the spiral passage 54 formed between the screw threads 26 and 46 in the cylinder 22 and on the rod, respectively. The pressure of the refrigerant is reduced progressively as the refrigerantfiows through the passage 54, the amount of pressure drop being determined by the depth of penetration of the plug or rod 48 in the threaded bore of the cylinder 22.

As the liquid refrigerant reaches the end of the spiral passage 54 it expands immediately into the space or chamber 18- and into the bore 16 formed in the rod 48. The expanded refrigerant thus changes into its gaseous state and then flows through the bore 42 and into the expansion or refrigeration coil [4 where it further expands and absorbs heat from the surrounding atmosphere. By the time the: gaseous refrigerant reaches the end of its passage through the coil l4 it has absorbed considerable heat from the surrounding atmosphere and it is then drawn into the compressor where it is condensed back into its liquid state.

From the above description it will be seen that, the invention comprises a restricting device which. can be used with any type of refrigerant, since. any desired pressure drop may be made by proper adjustment of the position of the rod 48 in the main bore 24 of the cylinder 22. The device may be easily disassembled for cleaning by first removing the cap member 36 from the cylinder 22 and then removing the threaded rod 48 from thebore 24 of the cylinder 22.

Many additional advantages arise by utilizing; a device of the type embodied in the invention. Vibration noises which are familiar to capillary tube installations are eliminated, whether the: device is used with a household standard temperature unit or with a plate type low temperature refrigeration unit. This novel type of evaporator unit having a built-in pressure reducing valve: balances the load on the compressormotor on. the off-cycle. Motors having low starting. torques may be used because of this balancing. feature, therefore, and the cost of manufacturing; the refrigeration system is correspondingly lowered. Also, the use of the present unit eliminatesthe use of a liquid receiver, and thereby less refrigerant is used or required for successful operation.

Referring now to Figs. 5 to 8 inclusive, wherein a modified form of the invention is illustrated, the restricting device 1 it is shown as constituting a built-in unit of an evaporator H2, similar to the unit l2 of Fig. l, and having a refrigerating or expansion coil I Hi associated therewith.

The restricting device iii! involves in its general organization an elongated tubular body, casing or cylinder i it having a threaded bore H8 formed therein adjacent its outlet end and an axially communicating counter-bore are adjacent its inlet end. The threaded bore Eli! communicates at the extreme outlet end of the cylinder with an outletport I22 which, in turn, communicates with one end of the cooling or refrigerating coil H4 which is preferably received Within a socket I24 provided in the end of the cylinder and which may be suitably secured therein by a welding or other operation. The cylinder H6 is formed with a substantially conical seating surface I26 in the vicinity of the outlet port I22 and which surrounds the latter for a purpose that will be set forth presently.

The counter-bore I at the inlet end of the cylinder H6 is provided with a laterally or radially extending inlet port I28 which is maintained in sealing relationship with one end of a tube or conduit I30 leading from the compressor or condenser stage of the refrigerating system. The threads which are formed in the bore H8 of the cylinder II6 are designated at I32 and are V-shaped in cross section and provide relatively deep trough portions I34 therebetween and relatively sharp crest portions I35. The threads I32 are adapted to engage mating screw threads I38 which are externally formed on an elongated internal adjusting and shut-off member in the form of a rod I40. The threads I38 on the rod I40 provide relatively sharp V-shaped troughs I42 therebetween and have relatively flat crest portions I44. These threads I38 are similar to the threads 40 in the form of the invention shown in Figs. 1 to 4, inclusive, and may be formed by a similar process, as for example by a cutting operation followed by a grinding operation as previously described.

The registry of the flat crest portions I44 of the threads I38 with the trough-s I34 provided by the teeth I32 provides a slender, elongated, spiral capillary path or passage I45 for the flow of refrigerant which is generally triangular in cross section.

As is the case in connection with the form of the invention shown in Figs. 1 to 4 inclusive, the extent of threaded reception of the threaded portion of the rod I40 within the threaded bore II8 determines the extent of the spiral passage I45 and consequently the degree of restriction offered to the flow of refrigerant through the device I I0.

In order to increase or decrease the extent of the spiral passage I45 the unthreaded portion of the rod I40 projects axially as at I43 from the inlet end of the cylinder I I6 and is provided with a flattened or otherwise deformed end I41 which, with the aid of a suitable tool such as a wrench, may be turned in one direction or the other to .decrease or increase the threaded extent of the rod within the bore IIS of the cylinder I I5. The Lextreme end of the cylinder IIS may be relieved internally as at I46 to provide an internal conical ;surface adapted to seat thereagainst a wedge ,shaped ring-like sealing washer I48 which is clamped thereagainst by means of a sealing cap I50, threadedly received on the end of the cylinder H5. The sealing washer I48 and cap member I50, in addition to their scaling function, provides a centering device for the outer end regions of the rod I40 to maintain the rod centered in the counter-bore I20. These members also, in effect, provide a locking means for anchoring the rod I40 in any desired position of adjustment. With the sealing cap I50 tightly and threadedly received upon the end of the cylinder H6 and with the sealing washer I48 under compression, the rod is frictionally held against turning movement thereof. Thus, when it is desired to effect adjustment of the threaded extent of the rod I40 within the cylinder I'I6, it is necessary to unloosen the cap member I50, after which adjustment the cap member may again be tightened.

The internal diameter of the counter-bore I20 is slightly in excess of the external diameter of the unthreaded portion of the rod I40, thus pro- III) viding an annular chamber or path for the flow of fluid from the inlet port I28 to the spiral passage I45. I

The inner end of the rod I40, i. e. the end thereof adjacent the outlet port I22, is provided with a smooth unthreaded portion I5I of a diameter substantially equal to the maximum internal diameter of the internally threaded portion I I8 of the cylinder H6. The extreme inner end of the rod I40 is beveled as at I52 to provide a seating surface designed for cooperation with the intern-a1 conical seating surface I26 formed in the cylinder H6 and which surrounds the outlet port I22.

From the above description of parts it will be seen that when the rod I40 is turned in a direction to increase the extent of its threaded reception within the threaded bore II8 of the cylinder IIB the conical seating surface I52 on the extreme inner end of the rod I40 will be moved toward the conical seating surface I26 provided in the cylinder H6 and surrounding the outlet port I22, while turning movement of the rod I40 in the opposite direction will move the seating surface I52 away from the seating surface I26. The relative positions of the two seating surfaces I52 and I26 afford no appreciable restricting function to the flow of fluid through the device IIO except insofar as complete shut off of fluid flow is concerned. Restriction to the flow of fluid through the device is dependent entirely upon the adjusted length of the spiral capillary fluid passage I45 and the overall cross section-a1 dimension of this fluid path is so extremely small that the flow of fluid through this path is not affected by any relative positioning of the seating surfaces I52 and I56 until such time as these two surfaces engage each other in sealing relationship and completely shut off the flow of fluid through the device.

The operation of the fluid restricting device H0 is similar to the operation of the device I0 illustrated in Figs. 1 to 4, inclusive, and refrigerant under pressure issuing from the tube of conduit I30 enters the inlet port I20 of the cylinder H6 and passes through the annular space existing between the counter-bore I20 and the unthreaded outer surface of the rod I40 from whence it passes to the spiral capillary restricted passage I45. The pressure of the refrigerant is reduced progressively as the refrigerant flows through the passage I45 and the amount of pressure drop across the passage is of course deter mined by the depth of penetration of the threaded portion of the rod I40 into the threaded bore II8 of the cylinder II6. As the liquid refrigerant reaches the outlet end of the spiral passage I45 it then enters the spiral passage afforded by the trough portions I44 existing between the teeth I32 and the smooth outer surface portion I5I provided on the rod I40. A slight amount of expansion of the refrigerant may occur in this relatively short spiral passage existing at the inner end of the rod I40 and after the liquid has passed through this spiral passage it then still further expands into that interior portion of the threaded bore I I8 not occupied by the rod I40, as well as expanding into the region afforded by the outlet port I42 and into the expansion coils I I4.

The expanded refrigerant thus is converted into its gaseous state as it flows through the expansion coil II4 so that heat is absorbed from the surrounding atmosphere in the usual manner.

The restricting device H0 in the form of the invention disclosed in Figs. 5 to 8, inclusive. ai-

fords a relatively simple means for effectively sealing off the flow of refrigerant through the device during such time as assembled refrigerating units as, for example, household refrigerators, deep freeze units, and the like embodying the principles of the present invention are in transit from the factory to the distributor or from the distributor to the scene of installation. When the rod M is received within the threaded bore H8 to the fullest threaded extent of which it is capable with the seating surface I52 bearing against the seating surface ['26, flow of the refrigerant through the spiral passage I45 is completely shut off and the unit may be shipped or otherwise handled in transit without danger of loss of refrigerant in the event that any of the communicating joints of the system become loosened or uncoupled. When the unit arrives at the scene of installation it is merely necessary for the installation worker or even the user to apply a suitable tool to the deformed end I41 of the rod I40 and turn the latter in such a direc tion as to relieve the seal existing between the seating surfaces 152 and I26, after which the system may be put into operation and the extent of threaded reception of the rod I40 in the threaded bore H8 adjusted to attain the most efficient rate of fluid flow through the system.

A further feature and advantage of the invention lies in the flushing capabilities thereof. When foreign matter in the refrigerant tends to clog the restricting passage, it is merely necessary to withdraw the rod I40 by unscrewing substantially halfway, whereupon the pressure of the refrigerant fluid will flush the device and force the foreign material therethrough.

Changes may be made in the form, construction and arrangement of parts from those disclosed herein without departing in any way from the spirit of the invention or sacrificing any of the attendant advantages thereof, provided, however, that such changes fall within the scope of the claim appended hereto.

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

A pressure reducing device for controlling the flow of refrigerant fluids in a refrigeration system comprising an elongated tubular member having an inlet and an outlet at opposite ends thereof, an axial bore of substantially constant diameter extending inwardly through said tubular member from the outlet end thereof for a predetermined distance, an axial counterbore within said tubular member of larger diameter than said first bore and communicating therewith, said counterbore extending through said tubular member at the inlet end thereof having a lateral inlet port, a set of continuous internal screw threads of constant diameter formed in said first bore, an elongated adjustable member of substantially constant diameter extending through said counterbore and said bore, at least a portion of said adjustable member having a set of continuous external screw threads of constant diameter threadedly engaging the internal screw threads in said bore, the crests of one of said sets of screw threads being flattened uniformly throughout the length thereof to provide a spiral passage of uniform cross section between the sets of screw threads, said adjustable member being movable axially of said first bore to vary the effective length of said spiral passage, said tubular member being formed with an inwardly facing valve seat around said outlet, and said adjustable member having one unthreaded portion extending through the counterbore and outwardly beyond the inlet of said tubular member and another unthreaded portion adjacent said outlet terminating in a reduced end complementally engageable with said valve seat to stop fluid flow through the device, a wedge-shaped sealing washer within the inlet end of said tubular member surrounding and engaging the adjacent unthreaded portion of said adjustable member, and means for releasably engaging said sealing washer and wedging the sealing washer tightly between the said adjustable member and the adjacent end of said counterbore to lock the adjustable member and said last named means against movement.

HERMAN M. GOLDBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Date

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