US2289905A - Refrigerating apparatus - Google Patents

Description

- n. s. DASHER REFRIGERATING APPARATUS July 14, 1942.

Filed March 9 1939 QATTORNEYS A a simple restrictorto provide a 'restrictor- Patented July 14,1942

"OFF-ICE aarmcnmrmo APPARATUS Don E. Dasher, Dayton,

eral Motors Corporatio ration of Delaware Ohio, assignor to Gen 11, Dayton, Ohio, a corpo- Application March 9,1939, Serial No. 260,789

' 6 Claims. (01. 62-127) This invention relates torefrigerating apparatus and more particularly to liquid control means for mechanical and absorption type refrigerating system.

Restrictors arev now used extensivelyin mechanical systems for different applications, particularly household refrigerators. The restrictors now being used are inflexible. I designed to provide the best eficiency only under a single condition ofload. For example, if the restrictor is designed to provide the best efficiency when the room temperature is 110, it will be much less satisfactory and less efficient for lower room temperatures, such as 70. If the restrictor is designed for best efficiency in a 90 room it will be less satisfactory and less efficient in a 110 arfa 70 room. Restrictors have been designed which find that these automatically adjustable types are not sufficiently accurate and "are not suffieiently reliable mechanically to justify their use.

{They can be are automatically adjustable, but I It is therefore an object of my invention to provide a restrictorwhich is simple mechanically and thoroughly reliable and which will accommodate its flow acording to varying room temperatures and load conditions to secure a. satisfactory flow of refrigerant and refrigerating efficiency over a relatively wide range.

It is another objectof my invention to provide which will reduce the crosssectional ,area as the pressure differential increases.

The use of restrictors in absorption systems has been negligible. This is largely due to the fact i that in the intermittent absorption. type'of refrigeration, which requires a pressure reducing device, it is desired to provide a restriction to the flow of liquid in one direction and to permit a free flow of evaporated refrigerant in the opposite direction when the cycle changes. Heretofore, no restricto'r so far as I am aware has accomplished this, butit has been necessary to provide a by-pass with other scheme in order to It is therefore another do this. object. of my invention which will permit free area of the spiral groove vis reduced.

- It is another object of my invention to provide a restrictor comprising a member having a grooved face and a second member capable of fitting against or'being withdrawn from the grooved face to close or open the grooves to provide a restricted or free now of fluid through the restrictor.

Further objects and advantages of the-present invention will 'be apparent from the following description, reference being. had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawing: j

Fig. 1 is a sectional view of a restrictor embodying my invention;

Fig. 2 is a view of the grooved face of one .of

the members of the restrictor shown in Fig. 1;

Fig. 3 shows the restrictor applied to a mechanical refrigerating system;

Fig. 4 shows an enlarged sectional view of a fragmentary portion of the restrictor passages; 1

Fig.5 shows two of the restrictors applied to a twin generator-absorber type of refrigerating system; and

' Fig. 6 is an enlarged fragmentary sectional view of a modified cooperating member.

Briefly, there isshown a restrictor comprising a memberhaving a grooved face which is normally held in engagement with a member of a.

existing between the inlet and the outlet of the restrict'or. The refrigerant enters spiral grooves at the outside of the grooved face and passes through to the outletprovided at the center. As the pressure differential increases the grooved member is pressed more tightly into the member of rubber-like material so that the cross-sectional When the V restrictor is used in a mechanical refrigerating a check valve or some flow of refrigerant in one direction and yet provide a properly restricted flow in the opposite direction.

It is another object of my invention to provide a restrictor in which the refrigerant is forced to pass throughout the passages in the restrictor in one direction while in the opposite direction it is permitted to flow freely without passing through the restrictor passages.

system the refrigerant always flows in one direction, but when-used in an intermittent absorption type system the pressure differential is reversed and the from the rubber-like member so frigerant can tion.

Referring to thedrawing and'moreparticularly to Fig. 3 there is shown a compression type of refrigerating system including a compressor 20 driven by an electric motor "for compressing the refrigerant and forwarding the compressed refrigerant to a condenser where the compressed refrigerant is liquefied and collected in a receiver 26. From the receiver II. the liquid refrigerant is i that the rereadily flow in the opposite direcgrooved member is pushed away diagrammatically for;

'refrigerating systems'is provided Its simplicity and lack of moving ample,

' cup-shaped member II is may be formed of p unded to give ticity or it may be aha-mentions pr p rl the desired ed from such materials. 7.5

under reduced pressures to cool the compartment 34 and is returned to the compressor through the return conduit 3. The operation of the motor-compressor unit is controlled by a thermostat switch 38 which is provided with a thermostat'control bulb 4| mounted upon the evaporating means 32.

Heretofore restrictors which have been used were formed either of a considerable length of small bore tubing or formed from a threaded metal restrictor. By employing an orifice of suiilcient length and proper cross-section a fairly satisfactory form of control for mechanical in this way. 7 parts is admirable. However, it is found that if the restricter is designed to provide the best eiiiciency load conditions, such as occur when the room temperature .is 110 F. that the efilcie'ncy is comparatively poor at lower room temperatures at which most of the operation is performed. For example,'if the restrictor is designed to provide 90 pounds head pressure and 12 inches back pressure under. 110 room temperature conditions, the restrictor would be too small for efllcient 70 room temperature operation and the back pressure would drop to 18 inches and the head pressure would fall to 50 pounds. By operating at 18 inches back pressure the'comunder heavy pressor would operate for a longer time --at a lesser efliciency andsince the thermostat switch was not set at .such a low temperature, the extremely low back pressure serves no useful purm' order to provide more efficient operation throughout the range itis desired to; keep the back pressure substantially constant. For exif the head pressure is 90 pounds and the back pressure is 12 inches in a 110 room, it is desired to keep the back pressure at about 12 inches in the '10". room. Since the compressor would compress gas more rapidly at this back pressure than at the 18' condenser pressure would probably rise to about 60 pounds. However, the restrictors heretofore used or proposed have not accomplished this.

In order to provide a restrictorwhich will provide such results I have evolved the restrictor shown in Figs. land 2. In this restrictor, generally designated by'the reference character 30, there is provided a cup-shaped member 50 which is connected to the liquid supply conduit 28 through a bossed central aperture 62. The

by acap member I4 which is threaded into the open end of the. cup-shaped member 50. The

cap member I4 is provided with a bossed aperture It which connects to the inlet of the evaporating means 32. in the cup-shaped member I is a disk 54 of a suitable rubber-like material having an aperture registering with the bossed aperture It in the member I4.- This disk shaped member Bl the desired softness and elasmade of some other other rubl 'or example, the disk may be compounded to g ve warded through the supply conduit 28 110 a restricter 3! which controlsthe'flow of refrigerant mown under the trade names of Duprene," Neoprene and Thiokol properly compounded to give satisfactory characteristics. Held pressed against the face of the disk 58 by the pressure difierential upon the restrictor is a cylindrical metal block SI having a face provided with a spiral groove 62 which extends spirally inwardly from the outer edge of the block 60 and a. recess 64 located in the center of the grooved face of the block. Between the adjacent convolutions of the groove 52 there is provided a. flat spiral land portion 66 which rests against the face of the rubber-like disk member 58 held against the inner wall-of the cap member 54.

desired this disk canized to this inner face of the cap member 54.

The restrictor 30 is preferably positioned so that the cylindrical metal block it rests by gravity upon the rubber-like disk 58. Where this arrangement is not desired, some means such as a spring or stop means may be used to hold the block 60 against the disk 58. Also if desired, the interior of the member 50 with sufllcient tightness that the pressure differential upon it will be suillcient to move and to hold it in engagement with the rubber-like disk 58.

Since the rubber-like disk 58 is soft and elastic the greater the pressure differential existing upon the block 60, the greater will be the pressure forcing the land or flats 66 of thevgrooved face of the block into the rubber-like material 58. The forcing of the grooved face into the rubber-like material 58 like material of the member I to flow slightly into the groove 62. Thus,

sure diflerential, the more rubber-like material I will be forced into the groove 62 to provide a greater reduction in the cross-sectional area of soften the material of the rubber-like disk 68 inch back pressure the closed at the other end the more readily the material of the disk 58 will be forced into the groove 2 to reduce the crosssectional area of the orifice. Thus by controlling the softness and elasticity of the disk 58, the amount of change in the cross-sectional area with a change in pressure can thereby be controlled. Instead of the rubber-like materials mentioned above other materials which are somewhat elastic and which can flow into the grooves may be used. For example, leather and other materials having similar properties might be used for this purpose.

It is also possible to vary the control thus provided by varying the shape of the grooves or by varying the width of the landor flats 6B and varying the depth of the grooves and by varying the length of the grooves to change the characteristics of the control provided by the foreing of the material of the disk 58 into the grooves. For example. it is evident that if the 8.181 of the flats 66 is reduced, the disk member 58 will oifer less resistance to the movement of the flats Within the chamber provided ordinary rubber properly com- 70 into its surface and thus more of the material of the disk 58 will be forced into the grooves 62. Likewise if the included angle of the groove 62 is increased, the material of the disk 58 will occupy av greater proportion of the cross-sectional area of the groove. It will also be evident that if the grooves are madesquare or half round in cross-section, the amount of material of the disk ll whichis pushed into the groove will provide aismaller percentage reduction in cross-secti :1 area of the orifice. Thus 58 may be cemented or vulwill cause the rubber-' the greater the prestem.

, stat valve which leads to the snap acting valve mechaan intermittent absorption type refrigeration sys- In Fig. one of the restrictors is used at each end of the evaporator in a twin generator type of absorption refrigerating system, which includes the generators I20 and I22 which are connected to the condensers I24 and I26 which in turn are connected to the restrictors I23 and I30 made like the restrictor 30. Connected between :the restrictoi's is an evaporating means I32 formed of a coil of, tubing which is'wrapped around a sleeve and located within the compartment I34 which is to be cooled.

The generators I20 and I22 are heated alternately by the gas burners I36 and I38 which are lighted'by individual pilot lights I40 and I42 connected directly to the gas supply line I44.

Gas is supplied alternately to the burners I36 5 and I38 according to the position of the twoway snap acting valve mechanism generallydesignated by the reference character I46. This two-way snap acting valve mechanism I46 is operated according to the temperatures of the thermostat bulbs I48 and I50 which are located in heat exchange relation with the generators I20 and I22. The thermostat bulbs I46 and I50 are connected to the bellows I52 and I54 to operate the two-way snap acting valve I 56.

As shown in Fig. 5, the generator I22 is being heated so that; refrigerant is driven from this generator-absorber to the condenser I26 where the refrigerant-is condensed and passes through the restrictor I30, into the evaporating means I32 where it evaporates under reduced pressure and flows freely through the restrictor I 25 and the condenser I24 to the absorber I20 which is being cooled by air which contacts with and cools its finned surfaces. The rate of .heating of the generator-absorbers is controlled by a thermo- I56 located in the gas supply pipe nism I46. This thermostatic valve I is'controlledv according to the temperature and the thermostat bulb I60 located in heat exchange relationship to the evaporating means I32. Thus the temperature of the evaporating means con- 1 trols the rate of gas supply to the burner which no islike is operated It'will'be seen that the restrictor the restrictor shown in Fig. 1. In this case the flow is from the condenser to the evaporator 'just as it is in Fig. 1 and the effect is the same, since the flow in restrictor 30 is from an inlet corresponding to the passage 52 in Fig. 1 to the outlet which corresponds to the passage 56 also in Fig. 1. Thus the restrictor I30 in the cycle shown will act just like the restrictor 30 in Fig. 3.

The restrictor I26 is positioned on the drawing just as the restrictor 30 is positioned in Fig. 1. However, the flow through the restrictor I26 during this cycle is in the direction opposite to the flow through restrictor 30 in Fig. 1. This reversed flow of course reverses the pressure differential .upon the restrictor and causes the cylindrical block, provided in the restrictor I 24,; corresponding to the cylindrical block 60 by Fig. 1, to be lifted or moved away from the disk of rubber-like'material corresponding to the disk epsaoos i 4 3 n of Fig. '1. This will allow the evaporated refrigerant from the evaporator I32 to flow freely through the restrictor I23 and the condenser I24 'to the absorber I26. This is ofcourse very desirable since any restrictionat thispoint in this cycle will reduce the eihciency of absorption in the absorber I20.

When the refrigerant within the generator I22 has been substantially driven on, the thermostat I50 will be heated, sumciently' to cause the valve I46 to operate to change the supply of gas from the burner I33 to the burnerl36. This will reverse the flow of refrigerant through the system and cause the restrictor I23 to restrict the flow in the manner'of the restrictor 30 in Fig. 3, while the restrictor I33 willpermit gas to escape freely'from the evaporating means I32 to 'the condenser I25 and thegenerator-absorber I22. Whenthe cylindrical block is lifted away from the disk of rubber-like material the gas will flow freely without passing through the grooves in the face of the block to an appreciable extent and will pass around the edges of the block to the other side of the block where it can flow freely into the condenser and generator-absorberwhich is absorbing at that time. Thus, this improved form of restrictor has the advantages of extreme simplicity and yet is capable of being used to great-advantage upon either compression systems or absorption refrigerating systems. I a

In Fig. 6 there is shown a modified form in which an extremely thin metal disk 250 covers the working surface of the rubber-like disk 258.'

If desired the thin metal disk 253 may be vulcanized or otherwise bonded to the surface of the rubber-like disk 255. The thin metal disk vmay be of brass or,copper or other suitable metal about 0.003 inch or 0.005 inch in thickness. This thin metal will protect the surface of the rubber-like disk 256 and, will reduce the amount of reduction in area of the grooves in the member 60. This construction is particularly useful where higher pressure diflerentials are required.

While the form of embodiment of the invention as herein disclosedfconstitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope o0.

of the claims which follow.

What is claimed is as follows: 1. A restrictor comprising a first member and a second member, one of said members being provided with a substantially flat portion and the other with a spiral groove in a portion of its surface, said spiral grooved portion being in contact with the flat portion of the other member to form an elongated passage of great length in proportion to its cross-sectional area, said spiral groove being provided with an end adjacent the outer edge and an end adjacent the center of one of said members, one of said ends 7 forming the inlet to the groove and the other the outlet, one of said members being freely mov- 65 able away from the other, said movable member and the other member being subject to the pressure of a fluid flowing through the groove to separate the members.

2. A restrictor comprising a member having a yielding elastic surface and a second member, one of said members being provided with a land and a groove in'a portion of its surface, said land of said grooved portion being in contact with a portion of the other member to form a passage between said members, said passage being provided with an inlet and an outlet, one of said members being freely movable away from the other to separate their adjacent surfaces, said movable member being subject to the pressure of the fluid flowing through the groove providing a separating force to, separate the adjacent surfaces of the members when the fluid flows in one direction and provided with pressure means acting in an opposite direction to hold the members together when the fluid flows in an opposite direction.

3. Refrigerating apparatus including evaporating means and liquefying means, restrictor means forming an elongated passage of great length in proportion to its cross sectional area for controlling the flow of fluid between the liquefying means and the evaporating means, andmeans responsive to an increase in pressure in the liquefying means for reducing the crosssectional area throughoutthe greater portion of said passage.

4. A resti ctor comprising a first member having a yielding elastic surface, a second member provided with a surface in contact with the elastic surface of said first member, one of said contacting surfaces being in the form of aland holding adjacent portions of the surfaces adjoining said land away from each other to provide a passage between the adjacent surfaces of said members, means for connecting the inlet and outlet of said restrictor to opposite ends of said passage, and means for continuously subjecting one of said members to a yielding force tending to hold the contacting surfaces of said members in engagement. said one member being freely movable under the influence of said yielding force.

5. A restrictor comprising a first member having a yielding elastic surface, a second member Y provided with a portion of its surface in cont tact with a portion of said elastic surface, one 10,

ofsaid surfaces being provided with a land and a recessed portion, said recessed portion providing a passage having an inlet and an outlet, and means for subjecting one of said members to a yielding force derived from the pressure of a fluid flowing through said passage for apply-= ing a contact pressure between said contacting surfaces for deforming said elastic surface to change the sizeof the passage.

6. A restrictor comprising a first member having a yielding elastic surface, a second member provided with a portion of its surface in contact with a portion of said elastic surface, one of said surfaces being provided with a land and a recessed portion, said recessed portion providing a passage having an inlet and an outlet, one-of said members being provided with means for applying a contact pressure between said contacting surfaces including means for applying a force to one of said members derived from a fluid pressure outside said passage.

DON E. DASHER.

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