The present invention relates to a hermetic type compressor suitable for use in cooling devices.

In hermetic compressors, the refrigerant is sucked from and pumped back to the refrigeration cycle by means of a piston operating in a cylinder. In hermetic compressors, the refrigerant with increased pressure and temperature while the refrigerant in the cylinder volume is compressed by the piston fills into the exhaust chamber in the cylinder head and from there is sent to the refrigeration cycle. The cylinder head in the compressor compensates the compressive stress occurring due to the compression of the refrigerant as a result of the piston movement and enables the refrigerant with high temperature and pressure to be delivered to the exhaust muffler. After being compressed by the piston and reaching a high pressure, the refrigerant is directed to the exhaust chamber, and the pressure difference between the interior of the compressor casing and the exhaust chamber in the cylinder head. In this case, the refrigerant leaks into the interior of the casing through the walls of the cylinder head and valve table, casing pressure losses due to the passage of the refrigerant into the casing and decreasing the pressure of the refrigerant introduced into the refrigerant cycle. Moreover, the mixing of the refrigerant with the lubricant in the casing causes a decrease in the refrigerant amount and lubrication problems.

In the International Application No. WO2012166051, a valve table used in a compressor and the thermal insulation embodiment are disclosed.

In the European Patent No. EP1960669 (B1), a hermetic compressor wherein thermal insulation is provided is disclosed.

In document US5577898A, a hermetic reciprocating compressor having a Suction muffler arrangement is disclosed. The compressor of this document comprises a channel arranged on a surface of a cylinder head and a rim on a surface of an insulating plate, wherein the rim of the insulating plate is fitted into the channel of the cylinder head. However, this document does not disclose a clamp which increases the pressing force between the cylinder head and the insulating plate.

In the US Patent No. US6553893B2, a piston assembly for reducing the temperature of a compressor cup seal having is disclosed.

In the International Application No. WO2017030986A1, a cylinder head for a compressor and a compressor including the head is disclosed. Further, a refrigeration system is also disclosed, including the compressor.

The aim of the present invention is the realization of a compressor wherein refrigerant losses are prevented by improving the sealing between the cylinder head and the valve table.

The compressor realized in order to attain the aim of the present invention is explicated in the claims.

The hermetic compressor comprises a valve table that is disposed between the cylinder and the cylinder head, that enables the refrigerant sucked from and pumped to the refrigeration cycle to be guided and whereon suction and exhaust ports and valves are disposed, and a cylinder heat that enables the pumped refrigerant to be directed. A plastic insulating plate is disposed between the valve table and the cylinder head so as to provide leak-proofing. In the embodiment of the present invention, in order to improve the leak-proofing between said insulating plate and the cylinder head, a channel that peripherally extends at the inner side of the edges of the cylinder head is provided, and a protrusion that is arranged on the surface of the insulating plate seated on the cylinder head and that is fitted into said channel is provided.

In an embodiment of the present invention, while the cylinder head is being mounted, the protrusion is press-fitted into the channel.

In an embodiment of the present invention, an o-ring is disposed between the protrusion and the channel.

In another embodiment of the present invention, in addition to said channel and protrusion, cavities are provided on the cylinder head and pins that are fitted into said cavities are provided on the insulating plate.

In the compressor of the present invention, the leak-proofing between the cylinder head and the valve table is improved, refrigerant losses are prevented and the performance is increased.

The compressor realized in order to attain the aim of the present invention is illustrated in the attached figures, where:

• Figure 1 - is the cross-sectional view of a compressor.
• Figure 2 - is the exploded view of a compressor body, a valve table, an insulating plate and a cylinder head.
• Figure 3 - is the schematic view of the insulating plate and the cylinder head in separated state in the embodiment of the present invention.
• Figure 4 - is the schematic view of the insulating plate and the cylinder head in joined state.
• Figure 5 - is the perspective view of a cylinder head.
• Figure 6 - is the perspective view of an insulating plate.
• Figure 7 - is the perspective view of a cylinder head whereon ribs are provided.
• Figure 8 - is the perspective view of the o-ring in an embodiment of the present invention.

The elements illustrated in the figures are numbered as follows:

1. 1. Compressor
2. 2. Casing
3. 3. Cylinder
4. 4. Piston
5. 5. Body
6. 6. Cylinder head
7. 7. Exhaust chamber
8. 8. Valve table
9. 9. Suction port
10. 10. Exhaust port
11. 11. Insulating plate
12. 12. Channel
13. 13. Rim
14. 14. O-ring
15. 15. Cavity
16. 16. Pin
17. 17. Rib
18. 18. Suction muffler
19. 19. Muffler head

The hermetic compressor (1) suitable for use for circulation of the refrigerant fluid in cooling devices, for example refrigerators, comprises a casing (2); a cylinder (3) that is disposed in the casing (2) and that enables the refrigerant to be sucked and pumped; a piston (4) that is operated in the cylinder (3); a body (5) that supports the cylinder (3) and the piston (4); a cylinder head (6) that enables the refrigerant sucked and pumped by means of the cylinder head (4) into the cylinder (3) to be directed; an exhaust chamber (7) that is disposed in the cylinder head (6) and wherein the pumped refrigerant fluid is accumulated; a metallic valve table (8) that is disposed between the cylinder (3) and the cylinder head (6); a suction port (9), an exhaust port (10) and suction and exhaust valves (not shown in figures) that are arranged on the valve table (8); an insulating plate (11) that is produced from a thermally insulating material, preferably plastic, and that is disposed between the valve table (8) and the cylinder head (6); a suction muffler (18) that enables the temperature of the refrigerant to be decreased and the noise caused by the refrigerant to be reduced, and a muffler head (19) that enables the refrigerant coming from the suction muffler (18) to be delivered to the cylinder (3) through the suction port (9).

The compressor (1) of the present invention comprises

• a channel (12) that is arranged on the surface, in contact with the insulating plate (11), of the cylinder head (6) and that peripherally extends at the inner side of the edges of the cylinder head (6) parallel to the edges such that a gap remains at the region where the muffler head (19) passes, and
• a rim (13) that is arranged on the surface, that is seated on the cylinder head (6), of the insulating plate (11), that peripherally extends at the inner side of the edges of the insulating plate (11) parallel to the edges such that a gap remains at the region where the muffler head (19) passes, and that is fitted into said channel (12) when the cylinder head (6) is mounted onto the cylinder (3).

The channel (12) is borne at a distance of 0.5 - 2.5 mm from the outer edge of the cylinder head (6) and has a depth of 0.5 - 2 mm. The rim (13) is formed at a distance of 0.5 - 2.5 mm from the outer edge of the insulating plate (11) and has a height of 2 mm. The tolerances of the dimensions of the channel (12) and the rim (13) are determined such that the rim (13) is mounted into the channel (12) in a press-fit manner.

By means of the channel (12) and rim (13) that are formed respectively on the opposite contacting surfaces of the cylinder head (6) and the insulating plate (11), the leak-proofing is improved and refrigerant losses into the casing (2) are prevented.

In an embodiment of the present invention, the compressor (1) comprises an o-ring (14) that is formed as an open curve so as to leave a gap where the muffler head (19) passes, that is fitted into the channel (12) and that is squeezed between the base of the channel (12) and the rim (13) (Figure 8).

In another embodiment of the present invention, the compressor (1) comprises a plurality of cavities (15) that are arranged on the surface, in contact with the insulating plate (11), of the cylinder head, at a region surrounded by the channel (12), and a plurality of deformable pins (16) that are provided at the surface, in contact with the cylinder head (6), of the insulating plate (11), at the region surrounded by the rim (13), that extend towards the cylinder head (6) in a direction perpendicular to the insulating plate (11) and that are crushed by being fitted into said cavities (15) (Figure 5, Figure 6).

In another embodiment of the present invention, the compressor (1) comprises a channel (12) the length of which is increased by bending outwards two opposite arms of the quadrilateral channel (12), and a rim (13) the length of which is increased by bending outwards two opposite arms thereof so as to be fitted into said channel (12). The channel (12) and the rim (13) with increased lengths, hence increased contact areas improve the leak-proofing, the strength and the centering of the cylinder head (6) with the insulating plate (11) - valve table (8) (Figure 5, Figure 6).

In another embodiment of the present invention, the compressor (1) comprises a plurality of ribs (17) that are disposed at the rear surface of the cylinder head (6) where the bolts are mounted and that extend from the center towards the edges and/or towards the corners where the bolt holes are arranged. The ribs (17) improve the strength of the cylinder head (6) and absorb the forces acting on the cylinder head (6) as a result of the movement of the piston (4) in the cylinder (3) (Figure 7).

According to the present invention, the compressor (1) comprises a clamp (not shown in figures) that is connected to the cylinder head (6) and the body (5) and that increases the pressing force of the cylinder head (6) onto the insulating plate (11), thus improving the leak-proofing.

In the compressor (1) of the present invention, the leak-proofing between the cylinder head (6) and the valve table (8) is improved, thus refrigerant leaks are prevented, the mass flow rate losses of the refrigerant are minimized, the coefficient of performance (COP) of the compressor (1) is increased, and the efficiency of the refrigeration cycle is improved. The need for using an elastomer gasket between the cylinder head (6) and the insulating plate (11) is eliminated, thus providing cost advantage.