US2089630A - Refrigerating apparatus - Google Patents

Description

' Aug 10, 1937. w. H. TE TER 9 2,089,630

REFRIGBRATING APPARATUS Filed July 19, 1934 7&1

24 s'uz 40 35 Patented Aug. 16, v.

. ammo Fries Wilford E. Teeter, Dayton, Ohio, omignor to General Motors Corporation, Dayton, Ohio, a corporation or Delaware Application July 19, recs, soul at. 730,031

This invention relates to refrigerating apparatits and more particularly to a valve for compressors for refrigerating app It is an object of the invention to provide a valve for passing refrigerant therethrough in one direction only, which is not only reliable, quick and positive in its action, but whichis also free from the production of noise in its operation.

It is also an object to provide a valve foring of refrigerant in one'direction only, which comprises really a pair of valves, one of which opens to a small degree very slightly before the other one opens, .to avoid a sudden change in 1 pressure between one side of the valve and the other and to thus eliminate noise in opening and closing. 1

Further objects and advantages of thepresent 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:

Fig. 1 is a diagrammatic view of a refrigerah 25 ing system embodying the present invention;

Fig. 2 is a vertical cross section of a compre'ssor piston embodying the present invention and showing the valve in closed position; I

Fig. 3 is a view corresponding to Fig. 2 showing 30 the valve in partly open position;

Fig. 4 13 a top view ota compressor piston embodying the present inventiomwhile Fig. 5 is a view corresponding to Fig. 4 with certain of the parts removed to illustrate the 35-'1J18t0h construction thereunder.

Referring now to Fig. .1, there is shown a refrige'rating system comprising a compressor ac having a piston i2 adapted to be reciprocated' in the usual manner in a cylinder MQA' dis- 0 charge valve i6 isiocated above the cylinder i l and communicates by a. dischsrgeconduit II with a condenser 29. lhe condenser so is connected to a liquid refrigerant receiver 22 which is in communication. by meansot c. conduit 24, 45 with the evaporator to which may contain the usual float valve (not shown) for regulating the expansion of refrigerant therein. A suction conduit 28 communicates between theevaporator J Hand the crankcase 2| of {the compressor ll, so and has a branch on containing a bellows 82 forming part of a low pressure control switch to for controlling I. motor I! which 'il-sdapted to drive the compressor II by suitable driving connections (not shown). I! The piston 12 containsan inlet valve mecha- (m. ESQ- 229) nism for passing gaseous refrigerant from the crank. case to the compression cylinder. The inlet vaive comprises an annular valve seat 29 within which is provided a series of passages ll communicating with the under side of the pis- '5' ton head. An auxiliary seat 52 is provided on the piston head concentric to the valve seat ii and inside the innermost portion oi the passages do. The face of the seat 42 is very slightly lower than the face of the seat 38. This feature 10 appears exaggerated in Figs. 2 and 3 in order to more clearly illustrate the invention. In practice, however on a valve of the order oi an inch in diameter, the seat 62 may-he approximately .004 or .005 of an inch below the seat 38 for best results. A valve disc M 01' a thin resil- I lent flexible material, such as spring steel, is adapted to rest on top of the seat 38 and is biased to close the valve by a leaf spring ii. A cover plate to is secured to the piston head by bolts to and provides a valve chamber 52 which is in communication with the'compression cylinder by a series of ports 54. A central aperture as is located in, the cover plate immediately above a corresponding central aperture 58 in the 35 valve disc I. I

In operation, gaseous refrigerant is withdrawn by the compressor from the evaporator 28 through the conduit 28. From the crank case, gaseous refrigerant passes through the piston valve into the cylinder it from whence it is compressed and ejected through the exhaust valve it and conveyed by the conduit i8 to the condenser 20. The refrigerant liquefied in the condenser 20 is collected in the receiver 22 from whence it is conveyed by the conduit 24 to the evaporator 26, where the float valve (not shown) admits liquid, refrigerant in amounts varying with the rate o1 vaporization therein. The switch 84 controls operation of the motor 88 ino accordance with thepressure conditions existing in theconduit 28 and evaporator 25.

The operation of the valve shown in Figs. 2 to 5 is such that on the compression or upward stroke of the piston, the parts lie in the position shown in Fig. 2, wherein the valve disc II is flexed by the pressure 0! the gas in the cylinder to close both the seat 38 and the seat 42, thus preventing mic of refrigerant from the cylinder back to the crank case. litter the como pression stroke is ended, and the piston begins its down stroke, the pressure diflerence between the two sides of the piston head is reduced to a point where the resilience of the disc 44 issuillcient to permit the some to straighten'out and rise 3 from the seat M as shown in Fig. 3. This provides a very small leakage path across the seat t? and through the aperture 58. As soon as the pressure in the cylinder is sumciently lower than that of the crank case to overcome the spring Alt, the entire valve disc l i is raised from the seat 3% permitting free passage of gas from the crank case to the cylinder it. At the bottom of the stroke, .the pressure of the cylinder and the lo crank case are again equalized and the valve disc 35% returns to the seat 38 while the leakage path across the seat 512 is still maintained open. After the piston again begins its compression stroke, the cylinder pressure increases above the i5 crank case pressure to a point suihcient to flew. the disc 6Q into the position shown in Fig. 2 wherein the leakage path across the seat 62 is again closed.

It will be seen that the provision of a small leakage immediately before opening of the main valve and immediately after closing thereof, tends to cushion both the opening and closing movements of the valve in that it prevents any sudden pressure changes between the two sides of the 2 valve such as occur in ordinary valves of this general type without the additional valve seat 62. It will he understood that while the invention has been illustrated as applied to a piston'valve, its advantages are likewise useful in other epplications such as for discharge valves for compressors and, in fact, in any, situation requiring a light, quick acting, one way valve which is not only positive and reliable in its action, but which must also m free from any noise in rapid operation.

While the form of embodiment of the inven tion as herein disclosed, constitutes'a preferred form, it is to be understood that other forms might be adopted, all'coming within the scope of the claims which follow. What-is claimed is as follows: l. A fluid control means operated by pressure diiierences thereon including means forming a throttling passage and a second passage, valve means for controlling the flow of fluid through said passages, said valve means being inherently biased to own the throttling passage and to close the second passage when no pressure difierential exists, said valve means being moved by one pressure differential to close both passages and being moved by an opposite pressure differential to open both mssages, said throttling passage being always open when said second passage is open and. being also opened to permit partial equalization of pressures immediately preceding the opening oi the second passage.

2. A fluid control means operated by pressure differences thereon including means forming a throttling passage and a second passage, valve means for controlling the how of fluid through said passages, said valve means being inherently biased to open the throttling passage and to close the second passage when no pressure differential emsts, said valve means being moved by one pressure differential to close both passages and being moved by an opposite pressure differential to open both passages, said throttling passage having a cross-sectional area less than one sixteenth the area of the maximum valve opening.

3. A compressor comprising a cylinder, 9. piston therein having a fluid control means comprising a plurality of valve seats located one within the other, one of said valve seats being slightly out of the plane of the other valve seat, a substantially fiat resilient disc valve adapted to make sealing engagement first with one of the valve seats and then with another, said valve being provided with a throttling passage opening into 7 more than four times the area enclosed by the second valve seat, said disc valve being provided with a throttling orifice therein opening into the confines 'of one of said valve seats, said throttling orifice having an area less than one-fourth the area enclosed by the smaller valve seat, said disc valve being wholly tree of any connection with either of the valve seats.

WILFORD H. 'IYEETER.

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