US2848157A - Compressor valve arrangement - Google Patents

Description

Aug. 19, 1958 R. w. AYLING COMPRESSOR VALVE ARRANGEMENT Filed June 26. 1953 I??? g mx INVENTOR. RM

1am fax United States Patent 9 COMPRESSOR VALVE ARRANGEMENT Robert W. Ayling, Utica, N. Y., assignor to Carrier Corporation, Syracuse, N. Y., a corporation of Delaware Application June 26, 1953, Serial No. 364,353

11 Claims. (Cl. 230231) This invention relates to compressors and, more particularly, to a novel valve arrangement for reciprocating hermetic compressors employed in refrigerating systems.

The efliciency of a reciprocating compressor depends to some extent on the head pressure. In reciprocating compressors, at the start of the suction stroke, there remains in the piston cylinder a small volume of the compressed fluid from the prior compression stroke. This left-over fluid is due to the fact that there must be a slight clearance between the top of the piston at the end of its stroke and the valve plate. This left-over fluid also occupies the discharge ports in the valve plate since the discharge valve is on the side of the valve plate opposite the piston.

The volume of the left-over fluid depends on the clearance between the piston and the valve plate and the thickness of the valve plate. If the thickness of the valve plate is substantially reduced, the volume of leftover fluid will be reduced proportionately.

The volume of this left-over fluid is particularly important where a very low suction pressure is required, as in food freezers. The ratio of the volume of this leftover fluid to the volume of incoming suction fluid Will depend on the ratio of the pressure in the head, which is the pressure of the left-over fluid, to the suction pressure. The lower the suction pressure in comparison to the head pressure, the greater volume the left-over fluid occupies at suction pressure. It is, of course, desirable to keep the volume of the left-over fluid at suction pressure as low as possible since it is not desired to recompress any more fluid than necessary.

If the volume of left-over fluid can be reduced, then the efficiency of the compressor will be increased. Since the compressor will be operating more efliciently, it will have a greater capacity with the same amount of power consumption.

The volume of left-over fluid is substantially reduced if the thickness of the valve plate is substantially reduced. However, in compressors presently employed, the valve plate must have a substantial thickness since it must withstand the pressure of the fluid in the cylinder when it is compressed by the piston and the difference in pressure between the head and the cylinder when the cylinder is at suction pressure. If the valve plate were not capable of withstanding this pressure, it would flex like a diaphragm and permit leakage between the valve plate and the head partitions, which separate the suction and discharge chambers.

I have satisfactorily solved this problem by providing a support means for the valve plate to permit the valve plate to be subtsantially reduced in thickness. This reduction in the thickness of the valve plate substantially decreases the volume of left-over fluid in the cylinder at the end of the discharge stroke so that the volume of left-over fluid in the cylinder at the end of the suction;

stroke is substantially decreased.

The support means may be disposed centrally of the valve plate and the cylinder head due to the novel ar- ""ice rangement of the suction and discharge ports, which are arrangement for a compressor which will permit a re-.

duction in the size of the compressor without an accompanying reduction in the capacity of the compressor.

An object of the invention is to provide .a smaller cylinder head for a compressor without decreasing the capacity of the compressor.

Another object of this invention is to provide a compressor that operates more efliciently than present compressors.

A further object is to provide a compressor valve assembly of novel design. Other objects of my invention will be readily perceived from the following description.

This invention relates to a reciprocating compressorincluding in combination a compression cylinder, a

cylinder head disposed above said cylinder, a valve plate,

disposed between said cylinder and said head, said plate having a plurality of openings therein, said openings lying on two different axes at substantially right angles to each other, means disposed below-the openings on one axis to permit ingress to said'cylinder, and means disposed above the openings on the other axis to permit,

egress.

This invention also relates to a valve plate having ports therein, said ports including discharge ports and suction ports, said discharge ports lying on an axis at substantially right angles to the axis of said suction ports.

The attached drawing illustrates a preferred embodiment of my invention, in which Figure 1 is a plan view of the valve plate of the present invention;

Figure 2 is a sectional view of the compression cylinder including the present invention; and

Figure 3 is a bottom plan view of the cylinder head of the present invention.

Referring to the drawing, and particularly to Figure 2, there is shown a reciprocating compressor including a piston cylinder 2 above which is disposed a cylinder head 3. A valve plate 4 serves to separate the cylinder head 3 from the cylinder 2. This valve plate preferably has a plurality of discharge ports 5 and suction ports 6 therein, as clearly shown in Figure 1. The discharge ports 5 are disposed on an axis at substantially right angles to the axis on which the suction ports 6 lie. Flow of gas through the discharge ports 5 is regulated by a valve reed 7. A suction valve reed 8 regulates the flow of gas through the suction ports 6. The suction valve reed 8 has a notch 9 at each side adjacent the axis of the discharge ports 5 for a purpose to be described hereinafter. Referring to Figure 3, the head 3 has a discharge,

chamber 12 and suction chambers 12'. Inlet tubes 30 communicate with suction chambers 12', and outlet tube 31 communicates with discharge chamber 12. The discharge chamber is disposed above the discharge ports 5 while a suction chamber 12' is disposed above each suction port 6. The discharge chamber is preferably a larger volume than the combined volume of the two suction chambers.

As clearly shown in Figure 3, the discharge chamber extends completely across the head. The discharge cham-- her is so designed that the walls dividing the discharge Patented'Aug. 19, 1958 chamber 12 from the suction chambers 12' are at a substantial distance from the middle of the head for a purpose to be hereinafter explained.

It will be understood that the entire head could serve as" the discharge chamber, if desired. The suction gas. could be supplied to the suction ports'by' tubes'passing through-the head.

A- gasltet 10-is provided between the valve plate 4' and the top of'cylinder 2 to prevent leakage. A similar gasket 11 is disposed between the valve plate 4 and the cylinder head 3. These gaskets are preferably made of amixture of polymerized polychloroprene and asbestos fibers but other suitable similar materials may be employed', if desired;

A valve bolt 14 placed centrally of the plate 4' is employed to' secure the valve plate 4 to the cylinder head 3. A nut 15 is threaded on to the end of valve bolt 14 to lock the valve plate 4 and. cylinder head 3 together. This bolt serves" to support the valve plate against the pressure differentials between the head' 3 and cylinder 2' so that a thin valve plate may be used. The positioning of the bolt 14' in the center of plate 4 provides the support for the plate 4. The location of the suction and discharge ports on axes at substantially right angles to each other permits the center location of the bolt. This is the most satisfactory and desired position for supporting the valve plate. It will be understood that a rivet could be employed instead of the bolt and nut, if desired.

Suctiongas flows by suitable means into the suction chambers 12. and then through the suction ports. 6 and past the suction valve reed 8 into the compression.

cylinder 2. Discharge gas flows from the cylinder. 2.

into the discharge ports and past the discharge valve.

reed 7 to the discharge chamber 12 of. the cylinder. head 3. From the head, the gas flows to the. condenser, notshown.

The discharge valve reed must be prevented from un-,

covering the discharge ports 5 until the gas has been compressed in the cylinder 2. To prevent the reedfrom lifting until the desired time, a discharge spring. 16 of the leaf type is employed. As clearly shown in Figure'2, this spring is designed to bear against the upper surface ofthe cylinder head 3. Theuse of this type of spring eliminates the necessity of a stop since this spring serves as. both a spring. and a stop. However, if desired,. a stop may be disposed above the discharge valve reed 7 andthe. leaf. spring. 16 replaced by a coil spring disposed' about the valve bolt 14. Other suitable means couldbe employed for preventing the discharge valve reed from uncovering. the discharge ports until the gas has been compressed in the cylinder 2.

The valve plate 4 is provided with openings 17. Similar openings 18 are provided in discharge valve reed 7.

When. the discharge valve reed is disposed above the valve plate 4, alignment is assured by aligning the openings 18 of reed 7 with the openings 17 of the valve plate; Dowel pins 19 are then disposed in these openings to prevent the reed from turning. Preferably, the dowel pins 19 fit tightly in the openings 17 of valve plate 4 in order to prevent leakage around the dowel pins.- As

will be noted from Figure 2, openingsZO are also provided in the leaf spring 16. The dowel pins 19 also pass through these openings to prevent the spring from turning. The dowel pins 19 are supported by head 21' of the valve screw 14 and bear. tightly thereagainst. This. head is so. designed, as shown in Figure 2, that the suction:

reed 8 may be disposed between the head 21 and the valve plate 4. The notches 9 of the valve reed 8' permit the suction valve reed to be located and prevented from turning by the dowel pins 19 since thesedowel pins fit into the notches 9 as clearly shown in Figure l. It will be noted that the dowel. pins are prevented from dropping into the cylinder by. the bolt head 21 if they should bccorneloose; It also will be noted that neither of the valve reeds are clamped to the valve plate by the valve bolt;

This invention has the advantage of permitting the valves of small hermetic compressors to be arranged in a compact relationship. This results in the use of a smaller cylinder head that may easily be a stamping, if desired. This, of course, results in a reduction in manufacturing expense and in the overall size of the compressor. Central support for the valve plate is provided thus permitting a substantial reduction in the thickness of the plate with an accompanying reduction in the amount of left-over fluid at the end of the compression stroke.

While Ilhave described a preferred embodiment of my invention, it will be understood that my invention is not limited thereto since it may be otherwise embodied within the scope of the following claims.

I claim:

1. In a reciprocating compressor including in combination a compression cylinder, a cylinder head disposed above the cylinder, a valve plate including a bore dis.- posed between the cylinder and the head, said valve plate including suction and discharge ports to provide communication between the head and the cylinder, said dischargeports and suction ports lying on axes at substantially right angles to each other, a valve reed including a bore disposed above said discharge ports, spring means above the reed in the head to permit the reed to lift to permit gases to flow through the discharge ports when the gas pressure in the cylinder reaches a predetermined amount, a valve reed including a bore disposed'below the suction ports, a bolt extending through said bores in said valve plate and valve reeds for securing said valve plate and valve reeds" relative to said cylinder. head, and means disposed in the valve plate in contact with both saidbolt and said reeds to prevent saidreeds from rotating relative to said ports.

2. In a reciprocating compressor including in combination a compression cylinder, a cylinder head disposed above. the cylinder, a valve plate disposed between the cylinder and'the head, said valve plate including suction and discharge ports to provide communication between the. head and the cylinder, said discharge ports and suction port-s lying on axes which cross each other, a valve reed disposed above said discharge ports, a valve reed disposed below the suction ports, a bolt to connect said reeds to said valve plate and said valve plate to the cylinder head, and means disposed in the valve plate in contact with said bolt adapted to locate both the discharge valve rced and the suction valve reed.

3. In a reciprocating compressor including in combination a compression cylinder, a cylinder head disposed above the cylinder, a valve plate disposed between the cylinder and the head, said valve plate including suction and discharge ports to provide communication between the head and the cylinder, said discharge ports and suction ports lying. on axes at substantially right anglesto each other, a valve reed disposed above said discharge ports, means above the reed in the head to permit the reed to lift to permit gases to flow through the discharge ports when the gas pressure in the cylinder reaches a predetermined amount, a valve reed disposed below the suction ports, a bolt having a head to connect the valve plate to the cylinder head, said bolt head being disposed in the compression cylinder, and dowel pins disposed in the valve plate, said dowel pins locating the discharge valve reed,.the lower portion ofthe dowel pins being disposed on. the face of the head of the bolt.

4-. In a reciprocating compressor including in combination a compression cylinder, a cylinder head disposed. above the cylinder, a valve plate disposed between the cylinder and the head, said valve plate including suction and. discharge ports to provide communication between the head and the cylinder, said discharge ports and suction ports: lying on axes at substantially right anglesto each other, avalve reed disposed above said discharge ports, means above the reed in the head to permit the reed to lift to permit gases to flow through the discharge ports when the gas pressure in the cylinder reaches a predetermined amount, a valve reed disposed below the suction ports, a bolt having a head to connect the valve plate to the cylinder head, said bolt head being disposed in the compression cylinder, and at least one dowel pin disposed in the valve plate, said dowel pin being in contact with and thereby preventing both the discharge valve reed and the suction valve reed from rotating relative to their respective ports, the lower portion of the dowel pin being disposed on the head of the bolt to prevent said pin from falling into said compression cylinder.

5. In a reciprocating compressor including in combination a compression cylinder, a cylinder head disposed above the cylinder, a valve plate disposed between the cylinder and the head, said valve plate including suction and discharge ports to provide communication between the head and the cylinder, said discharge ports and suction ports lying on axes which cross each other, a valve reed disposed above said discharge ports, means above the reed in the head to permit the reed to lift to permit gases to flow through the discharge ports when the gas pressure in the cylinder reaches a predetermined amount, a valve reed disposed below the suction ports, a member supporting the valve plate from the cylinder head, and means disposed relative to said valve plate in contact with at least one of said reeds and with said member to prevent said reed from rotating relative to its respective ports.

6. In a reciprocating compressor including in combination a compression cylinder, a cylinder head disposed above the cylinder, a valve plate disposed between the cylinder and the head, said valve plate including suction and discharge ports to provide communication between the head and the cylinder, said discharge ports and suction ports lying on axes at substantially right angles to each other, a valve reed disposed above said discharge ports, means above the reed in the head to permit the reed to lift to permit gases to flow through the discharge ports when the gas pressure in the cylinder reaches a predetermined amount, a valve reed disposed below the suction ports, a member centrally disposed of the valve plate to support the valve plate from the cylinder head and to hold said reeds and said valve plate in assembled condition, and means disposed in the valve plate in contact with both said last mentioned member and reeds for preventing said reeds fi'om rotating away from operative relationship with said ports.

7. In a reciprocating compressor including in combination a compression cylinder, a cylinder head disposed above the cylinder, a valve plate disposed between the cylinder and the head, said valve plate including suction and discharge ports to provide communication between the head and the cylinder, said discharge ports and suction ports lying on axes at substantially right angles to each other, said head cooperating with said valve plate to form at least three chambers in the head, one of said chambers being above the discharge ports, each of said other chambers being disposed above one of said suction ports, said first chamber being disposed in the central portion of said head and segregating said other chambers from each other, a valve reed disposed above said discharge ports, means above the reed in the head to permit the reed to lift to permit gases to fiow through the discharge ports When the gas pressure in the cylinder reaches a predetermined amount, and means closing the suction ports adapted to permit gas to enter the cylinder when the gas pressure in the cylinder is below a predetermined amount.

8. A valve assembly for a compressor comprising a plate member having suction and discharge ports extending therethrough, a first reed member in engagement with one surface of the plate overlying said suction ports, a second reed member in engagement with the opposed surface of the plate overlying said discharge ports, means for preventing separation of the parts including a headed fastening element and at least one pin extending through the superposed parts with one end of the pin in engagement with the headed portion of the fastening element.

9. A valve assembly for a compressor comprising a valve plate having a port extending therethrough, a reed mounted on said plate, a fastening member for securing said reed to said plate while allowing said reed to selectively open and close said port during operation of said compressor, and centering means in engagement with said reed to prevent said reed from turning relative to said plate, said fastening member being in contact with said centering means to prevent the latter from being dislodged from operative relationship with said reed during operation of said compressor.

10. A valve assembly as set forth in claim 9 wherein said fastening member has a headed portion and said centering means consists of a pin, said pin being in engagement with said headed portion.

11. The arrangement described in claim 8 wherein one of said reed members is provided with a peripheral notch to accommodate the pin.

References Cited in the file of this patent UNITED STATES PATENTS 1,408,638 Prellwitz Mar. 7, 1922 1,425,663 Lawhead Aug. 15, 1922 1,672,125 Heideman June 5, 1928 2,062,206 Browne Nov. 24, 1936 FOREIGN PATENTS 10,503 Great Britain May 3, 1910 240,876 Switzerland May 16, 1946

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