WO2015059061A1

WO2015059061A1 - Reciprocating compressor having an improved valve and method for assembling the compressor

Info

Publication number: WO2015059061A1
Application number: PCT/EP2014/072380
Authority: WO
Inventors: Bertrand Carpentier
Original assignee: Tecumseh Europe S.A
Priority date: 2013-10-22
Filing date: 2014-10-17
Publication date: 2015-04-30
Also published as: EP3060804A1; FR3012182B1; FR3012182A1

Abstract

The invention relates to a reciprocating compressor (10) of a fluid and to a method for assembling the compressor. The compressor includes a valve plate (14) and a cylinder head (13) arranged on the valve plate (14). The valve plate (14) includes a delivery port (18) passing through the valve plate (14) and a delivery valve (22). According to the invention, the valve plate (14) includes a recess (24) having a flat bottom (26) parallel to the valve plate (14), the delivery port (13) being provided in the bottom (26) of the recess (25). The delivery valve (22) is made of a blade substantially occupying the bottom (26) of the recess (25). The compressor (10) includes, in addition, a spring (28) supported between the delivery valve (22) and the cylinder head (13).

Description

Improved clamshell reciprocating compressor and method of assembling the compressor

The invention relates to an alternative compressor for compressing a fluid, especially a refrigerant. The invention also relates to a method of assembling the compressor. This type of compressor comprises a cylinder and a piston moving in the cylinder to compress the fluid.

In reciprocating fluid compressors known, a valve plate is provided to allow the admission of the fluid to a compression system itself, that is to say in a variable volume formed between the piston and the cylinder. The valve plate is also provided so as to allow the suction and discharge of the compressed fluid through openings in the plate, orifices closed respectively by suction and discharge valves.

Valves are usually attached to the valve plate. The suction valve is fixed on one face of the valve plate, face located on the side of the cylinder and the discharge valve is fixed on the other side of the valve plate generally by separate means. The valves are for example formed of spring steel blades coming to open or close the orifices of the valve plate according to the phases of an operating cycle of the compression system. The operating cycle usually involves suction, compression and discharge phases.

In the known solutions, screws, rivets or other elements are used to hold the flaps on the valve plate. Known compressors often include a stop to limit the stroke of the discharge valve. This stop is usually fixed with the discharge valve on the valve plate.

The assembly elements have several disadvantages, for example:

Deformations related to the assembly elements which generate mechanical stresses, in particular in the flap plate, • risks of leakage when the assembly elements pass through the valve plate,

• a long and risky assembly process due to the need to control the assembly of these elements; in the case of a screw connection it is necessary to control the tightening torque of the screw and in a rivet connection it is necessary to control the riveting parameters.

The invention aims to overcome all or part of the problems mentioned above by providing a compressor in which the assembly of the discharge valve is greatly simplified.

For this purpose, the subject of the invention is an alternative compressor comprising:

• a cylinder,

A piston moving in the cylinder to compress a fluid,

A valve plate comprising a first and a second face parallel to each other, the valve plate closing by its first face a variable compression chamber formed between the piston and the cylinder;

A yoke disposed on the second face of the valve plate, the yoke comprising a discharge chamber intended to receive the compressed fluid,

• a discharge valve,

the valve plate comprising a discharge orifice passing through the valve plate and putting the compression chamber into communication with the discharge chamber, the discharge valve for opening and closing the discharge orifice, the opening of the valve when the pressure of the fluid in the compression chamber is greater than the pressure of the fluid in the discharge chamber, the valve plate comprising a blind housing having a flat bottom parallel to the faces of the valve plate and opening on the second face, the discharge orifice being formed between the bottom of the housing and the first face,

the discharge valve being formed of a blade disposed in the housing and occupying substantially the bottom of the housing, the compressor further comprising a spring bearing between the discharge valve and the cylinder head.

According to the invention the housing and the spring comprise complementary shapes configured so as to maintain the spring bearing against the discharge valve and to maintain the discharge valve bearing against the valve plate in the absence of the cylinder head.

The subject of the invention is also a method for assembling a compressor produced according to the invention, characterized in that it consists in following in sequence the following operations:

• put the discharge valve on the bottom of the housing,

• put the spring on the discharge valve,

• exert pressure on the spring between its two ends so as to engage the complementary shapes,

· Release the pressure on the spring.

By implementing the invention, it eliminates any assembly element of the discharge valve on the valve plate. For the assembly of the valve, only the spring is used which can advantageously fulfill the stop function of the discharge valve.

The removal of any assembly element avoids any risk of leakage and deformation of the valve plate.

The invention will be better understood and other advantages will appear on reading the detailed description of an embodiment given by way of example, a description illustrated by the attached drawing in which:

Figure 1 shows in partial section an alternative compressor according to the invention;

Figure 2 shows a valve plate of the compressor of Figure 1;

Figure 3 shows an exploded view of the valve plate, its valves and a cylinder head of the compressor.

For the sake of clarity, the same elements will bear the same references in the different figures. Figure 1 partially shows an alternative compressor 10 for compressing a fluid. The compressor 10 comprises a cylinder 1 1, a piston 12, a yoke 13 and a valve plate 14. The piston 12 moves in the cylinder 1 1 in a reciprocating translational movement along an axis 15. This movement can be obtained at from a rotary engine. The transformation of movement of the rotation of the motor towards the translation of the piston 12 can be achieved by a crank system not shown in FIG. 1. The valve plate 14 caps the cylinder January 1 to form a compression chamber 16 with the piston 12. The compression chamber 16 has a variable volume. In Figure 1, the piston 12 is shown at its top dead center and the volume of the compression chamber 16 is virtually zero. The yoke 13 overhangs the valve plate 14.

It is possible to implement the invention in a compressor having a plurality of piston and cylinder torques.

The cylinder head 13 comprises an intake chamber, not visible in FIG. 1, in which the fluid circulates before compression and a discharge chamber 17 in which the compressed fluid circulates. The valve plate 14 includes orifices for communicating the chambers with the compression chamber. A suction port communicating the inlet chamber with the compression chamber does not appear in the section plane of FIG. Two discharge ports 18 appear in FIG. 1 and make the delivery chamber 17 communicate with the compression chamber 16. The two orifices 18 are given only by way of example. The invention can be implemented with a single orifice or with more than two.

The valve plate 14 is flat and has two parallel main faces 19 and 20. The face 19 is in contact with the cylinder 1 1 and the face 20 is in contact with the cylinder head 13. Seals can be placed a part between the yoke 13 and the valve plate 14 and secondly between the valve plate 14 and the cylinder 1 1. The valve plate 14 carries on its face 19 a suction valve 21, visible in Figure 3 and for closing temporarily the suction port and on its face 20 a discharge valve 22 for closing temporarily the l 18. More specifically, the opening and closing of the valves 21 and 22 is made according to the pressure differences between the chambers. These differences pressure depend on the position of the piston 12 in the cylinder 1 1. The valves 21 and 22 extend in a closed position flat on their respective face of the valve plate 14. According to the invention, the valve plate 14 comprises a blind housing 25 having a flat bottom 26 parallel to the faces 19 and 20 and opening on the face 20. The housing 25 is preferably blind except the or the discharge ports 18 which are formed between the bottom 26 of the housing 25 and the face 19. The discharge valve 22 is formed of a blade disposed in the housing 25 and substantially occupies the bottom 26 of the housing 25. Advantageously, the discharge valve 22 does not include any drilling therethrough. It is formed of an elastic blade having a substantially rectangular contour.

The compressor 10 further comprises a spring 28 supported between the discharge valve 22 and the cylinder head 13. The spring 28 can bear on the cylinder head 13 and on the discharge valve 22 at the axis 15 or between the two discharge ports 18. The spring 28 then has only two bearing points, one on the cylinder head 13 and one on the discharge valve 22.

An alternative and advantageous form of the spring 28 is clearly visible in FIG. 2 which represents the valve plate in plan view perpendicular to the axis 15.

Figure 3 also illustrates this advantageous form. 3 shows an exploded view the valve plate 14, the valves 21 and 22, the springs 28 associated with each discharge valve 22 and the cylinder head

13.

In the example shown, the compressor 10 comprises two discharge valves 22 associated with the same piston 12. The number of discharge valves can vary without departing from the scope of the invention. A spring 28 is associated with each of the discharge valves 22. In FIG. 2, the two springs 28 conceal the valves 22. The springs 28, the valves 22 and the associated discharge orifices 18 are advantageously identical. Subsequently, only one of the jurisdictions will be described.

In the variant shown, the spring 28 has three bearing points, two on the valve plate 14 and one on the cylinder head 13. More precisely, the spring 28 is formed of a curved blade extending in a main direction 29 between two ends 31 and 32. The spring 28 bears at its two ends 31 and 32 on the discharge valve 22. The spring 28 takes support on the yoke 13 between its two ends 31 and 32 and preferably at mid-distance between its two ends 31 and 32. The discharge orifice or the discharge orifices 18 are located between the two ends 31 and 32 of the spring 28.

In operation, when the pressure of the fluid in the compression chamber 16 is less than or equal to the pressure of the fluid in the discharge chamber 17, the discharge valve 22 remains in abutment against the bottom 26 of the housing 25, as shown in FIG. figure 1 . When the pressure of the fluid in the compression chamber 16 becomes greater than the pressure of the fluid in the discharge chamber 17, the discharge valve 22 deforms and separates from the bottom 26 of the housing 25 at the openings 18 while remaining in position. bearing on the bottom 26 at the ends 31 and 32. The discharge valve 22 may deform to the point of coming into contact with the spring 28. At the discharge orifices 18, the housing has a width, perpendicular to the main direction 29, greater than that of the valve 22 and the spring 28 so as to allow the passage of the compressed fluid from the orifices 18 to the discharge chamber 17.

When the compressor 10 is assembled, no element comes to fix the valve 22 and the spring 28 ni to the valve plate 14 or to the cylinder head 13. The valve 22 and the spring 28 associated therewith are simply placed in the housing 25 The shape of the housing 25 is sufficient to hold in place the valve 22 and its spring 28.

This device can pose a problem during the assembly of the compressor 10. Indeed, the holding in position of the valve 22 and its spring is obtained by gravity before the assembly of the cylinder head 13. This requires maintaining the valve plate 14 so that its face 20 is arranged upwards.

It is possible to further improve the assembly by allowing further manipulations of the valve plate 14 during the assembly of the compressor 10. The objective is to maintain the valve 22 and its spring 28 as obtained with the embodiments of the prior art but without fastening means of the rivet or screw type.

For this purpose, the housing 25 and the spring 28 comprise complementary shapes configured to hold the spring 28 in abutment against the valve 22 and to hold the valve 22 in abutment against the valve plate 14 in the absence of the cylinder head 13. The complementary shapes allow for example to maintain the valve 22 and its spring 28 by adhesion in the housing. For this purpose, the spring 28 comprises lugs 33 intended to bear against lateral faces 34 of the housing 25. The lugs 33 extending perpendicular to the main direction 29 and the lateral faces 34 are perpendicular to the main direction 29 and perpendicular at the bottom 26 of housing 25.

During assembly of the valve plate 14 before the installation of the cylinder head 13, the assembly of the compressor 10 consists of sequencing the following operations in the following order:

• put the discharge valve 22 on the bottom 26 of the housing 25,

• put the spring 28 on the discharge valve 22,

Exerting pressure on the spring 28 between its two ends 31 and 32 so as to engage the complementary shapes 33 and 34,

· Release the pressure exerted on the spring 28.

The pressure on the spring 28 flattens the spring 28 and tends to move the lugs 33 in the direction 29. The lugs 33 can then slide along the lateral faces 34. The fact of releasing the pressure tends to bring the lugs 33 and to put them in abutment against the lateral faces 34. The tension of the spring 28 allows a lug 33 to exert a force on the lateral face 34 opposite. The force F combined with a coefficient of friction of the lug 33 relative to the lateral face 34 allows the spring 28 to be held in the housing 25.

After mounting the valve 22 and its spring 28, the cylinder head 13 is assembled on the face 20 of the valve plate 14. After the cylinder head 13 has been put in place, it is possible to retain the pins 33 of the spring 28 against the lateral faces 34 of the valve plate 14. Alternatively the mounting of the cylinder head 13 can release the force F. This is achieved by means of a support of the yoke 13 on the spring 28 between its two ends 31 and 32 The cylinder head 13 exerts on the spring 28 a pressure similar to the pressure exerted by an operator during the mounting of the spring 28 on the valve plate 14. For this purpose, the yoke 13 comprises a zone d ' support 36 on the spring 28. The yoke may comprise a flat surface intended to come into contact with the face 20 of the valve plate 14, possibly by interposing a seal 37 between the yoke 13 and the valve plate 14. The bearing zone 36 is located on this flat surface.

In the absence of yoke 13, when the spring 28 and the valve 22 are assembled on the valve plate 14, a central zone 38 of the spring 28, located at a distance from its two ends 31 and 32, projects beyond the face 20 When mounting the cylinder head 13, the bearing zone 36 presses on the spring 28 in its central zone 38 to return the spring 28 completely inside the housing 26 without overflowing the face 20, which allows to release the support of the lugs 33 against the lateral faces 34. In other words, the complementary shapes 33 and 34 are configured so as to release the support when the yoke 13 presses the spring 28, holding the spring 28 in abutment against the valve 22 and holding the valve 22 in abutment against the valve plate 14 obtained in the absence of cylinder head 13.

Thus the only forces exerted on the spring 28 are parallel to the axis 15. This allows better control of the support of the spring 28 against the valve 22. This also ensures a precise position of the spring 28 in its function of stop in the displacement of the valve 22 when it is opened under the effect of the pressure of the fluid in the compression chamber 16.

Claims

1. Reciprocating compressor comprising:

A cylinder (1 1),

A piston (12) moving in the cylinder (1 1) for compressing a fluid,

A valve plate (14) comprising first and second faces (19, 20) parallel to one another, the valve plate (14) closing by its first face (19) a variable compression chamber (16) arranged between the piston (12) and the cylinder (1 1),

A yoke (13) disposed on the second face (20) of the valve plate (14), the yoke (13) comprising a discharge chamber

(17) for receiving the compressed fluid,

• a discharge valve (22),

the valve plate (14) comprising a discharge orifice (18) passing through the valve plate (14) and placing the compression chamber (16) in communication with the discharge chamber (17), the discharge valve (22) for opening and closing the discharge port (18), the discharge valve opening (22) being effected when the pressure of the fluid in the compression chamber (16) is greater than the pressure of the fluid in the discharge chamber (17),

the valve plate (14) comprising a housing (25) having a flat bottom (26) parallel to the faces (19,20) of the valve plate (14) and opening to the second face (20); discharge orifice (18) being formed between the bottom (26) of the housing (25) and the first face (19),

the discharge valve (22) being formed of a blade disposed in the housing (25) and occupying substantially the bottom (26) of the housing (25), the compressor (10) further comprising a spring (28) supporting between the discharge valve (22) and the cylinder head (13),

the compressor (10) being characterized in that the housing (25) and the spring (28) comprise complementary shapes (33, 34) configured to maintain the spring (28) bearing against the discharge valve (22) and keeping the discharge valve (22) bearing against the valve plate (14) in the absence of the cylinder head (13).

2. Compressor according to claim 1, characterized in that the discharge valve (22) comprises no drilling therethrough.

3. Compressor according to one of the preceding claims, characterized in that the spring (28) is formed of a domed blade extending in a main direction (29) between two ends (31, 32), in that the spring (28) bears against these two ends (31, 32) on the discharge valve (22) and in that the spring (28) bears on the yoke (13) between its two ends (31, 32).

4. Compressor according to claim 3, characterized in that the discharge port (18) is located between the two ends (31, 32) of the spring (28).

5. Compressor according to one of the preceding claims, characterized in that the housing (25) is blind except the discharge port (18).

6. Compressor according to one of the preceding claims, characterized in that the complementary shapes comprise, for the spring (28) lugs (33) and for the housing (25) side faces (34), the complementary shapes being defined. so as to allow the discharge valve (22) and the spring (28) to be held by adhesion in the housing (25) in the absence of the cylinder head (13).

7. Compressor according to claim 6, characterized in that the lugs (33) extend perpendicularly to the main direction (29) and in that the lateral faces (34) are perpendicular to the main direction (29) and perpendicular to the bottom (26) of the housing (25).

8. Compressor according to one of the preceding claims, characterized in that the yoke (13) comprises a bearing zone (36) on the spring (28) and in that the complementary shapes (33, 34) are configured from to release the support when the yoke (13) rests on the spring (28).

9. A method of assembling a compressor according to one of the preceding claims, characterized in that it consists in sequencing the following operations:

· Put the discharge valve (22) on the bottom (26) of the housing (25),

• put the spring (28) on the discharge valve (22),

• exerting pressure on the spring (28) between its two ends (31, 32) so as to engage the complementary shapes (33, 34),

• Release the pressure on the spring (28).