Description A COMPRESSOR
[001] This invention relates to a compressor, preferably used in the refrigerators, having an improved gas flow performance in the cylinder during the pumping of the cooling gas into the system.
[002] In hermetic compressors which are preferably used in the refrigerators a piston is used for the suction of the cooling gas and pumping it in to the system and a cylinder into which a piston is placed. There are gas suction and outlet orifices on the cylinder. Piston moves back in the cylinder during the gas suction process thereby taking the gas from the suction orifice into the cylmder and it moves forward in the cylinder thereby compressing the gas and discharging the gas out of the cylinder through the outlet orifice. One of the criteria for the efficient operation of the compressor is related to which rate of the discharge taking the gas in the cylinder in one cycle. When the piston compresses the gas, some amount of the gas in the gap formed by the outlet nozzle is not discharged thereby causing the decrease in the efficiency of the compressor.
[003] In state of the art, French Patent No. 2617242 discloses a pin on the piston that fits in the outlet orifice during the compression of the gas and reduces the unused volume. Pin and outlet orifice may have either cylindrical or frusto-conical form having conformable sizes for each other. Since the flow area where the gas is discharged narrows and pin covers the whole of outlet orifice when the pin fits into the outlet orifice, discharge of the gas is got difficult and increasing the losses are caused due to the turbulences. The advantage gained by the reduction in the unused volume is lost by the impediment in the flow.
[004] In state of the art, American Patent 5816783 defines a pin and an outlet orifice on the piston having a frusto-conical structure. As the slope of the pin is smaller than the slope of the side wall of the outlet orifice, narrowing in the flow area is partially reduced when the pin is fitted into the outlet orifice.
[005] In state of the art, European Patent 0823022 defines a pin and an outlet orifice on the piston having an asymmetrical structure. The flow is partially improved by the pin formed asymmetrically according to the direction of the flow.
[006] The object of this invention is to provide a compressor, preferably used in the refrigerators, having an improved gas flow performance during pumping the cooling gas into the system.
[007] The compressor realized in order to attain the objects of the present invention has been illustrated in the drawings, wherein
[008] Figure 1 is a cross sectional view of a compressor.
[009] Figure 2 is a schematic cross sectional view of a valve table, a cylinder and a piston having a pin in the position when the pin is fitted into the outlet orifice.
[010] Figure 3 is a schematic cross sectional view of a valve table, a cylinder and a piston
having a pin in the position before the pin is fitted into the outlet orifice. [Oil] Figure 4 is a top schematic view of a valve table, a cylinder and a piston having a pin in the position when the pin is fitted into the outlet orifice. [012] The components shown in the drawings have been enumerated as follows: 1. Compressor 2. Lower housing 3. Cylmder 4. Piston 5. Crankshaft 6. Connecting Rod 7. Piston Pin 8. Cylinder head 9. Upper housing 10. Suction muffler 11. Valve table 12. Gasket 13. Outlet orifice 14. Outlet valve 15. Protrusion 16. Piston pressure surface 17. Cylmder inner wall
[013] The circulation of the fluid of the cycle which is used for cooling in the household appliances preferably in the refrigerators is provided by the hermetic compressor (1) with piston. In a preferred embodiment, cooling gas is used as the fluid of the cycle.
[014] The compressor (1) comprises a lower housing (2) which carries the components inside, an upper housing (9) on the lower housing (2), a cylinder (3) placed in the lower housing (2) and upper housing (9) to provide the pumping of the cooling gas inside, a cylinder head (8) on the cylinder (3) which circulates the sucked and compressed cooling gas, a valve table (11) onto which a cylinder head (8) is placed, a piston (4) which is provided to compress the cooling gas into the cylinder orifice, a gasket (12) which is placed between the cylinder (3) and the valve table (11) to prevent the direct strike of the piston (4) with the valve table (11), a crank (5) which transfers the motion from the motor, a connecting rod (6) which converts the circular motion of the crank (5) into the linear motion and transfers it to the piston (4), a piston pin (7) which connects the connecting rod (6) to the piston (4) and a suction muffler (10) preferably made of plastic material, which provides to reach that is not heating and prevents the noise which may be caused by the cooling gas until it is transferred to the cylinder region.
[015] Valve table (11) comprises an outlet orifice (13) in which the cooling gas that is taking into the cylinder (3) is discharged and an outlet cover (14) which covers the
outlet orifice (13) and prevents the discharge of the cooling gas in the cylinder (3) to outside during the suction process.
[016] Piston (4) comprises a protrusion (15) which fits into the outlet orifice (13) and reduces the unused volume formed during the compression process and a piston pressure surface (16) which fits onto the gasket (12).
[017] Cylinder (3) comprises a cylinder inner wall (17) on which the piston (4) moves.
[018] In order to improve the gas flow performance while reducing the unused volume, central axis (cl) of the protrusion (15) and the central axis (c2) of the outlet orifice (13) should not coincide with each other when the protrusion (15) fits into the outlet orifice (13). When the protrusion (15) fits into the outlet orifice (13) as a result of the eccentricity between the central axis (cl) of the protrusion (15) and the central axis (c2) of the outlet orifice (13), the width (dl) of the higher flow region of the gas which is close to the central axis (c3) of the cylinder (3) is greater than the width (d2) of the lower flow region of the gas which is close to cylinder inner wall (17). It is preferably 5/2d2 > dl > 3/2d2.
[019] The protrusion (15) and the outlet orifice (13) have a frusto-conical form. The angle (#1) between the side wall of the protrusion (15) and the piston pressure surface (16) is almost equal to the angle (#2) between the side wall of the outlet orifice (13) and the piston pressure surface (16).
[020] The base diameter (rl) of the protrusion (15) is lower than the base diameter (r2) of the outlet orifice (13). The rate of rl/r2 is preferably lower than 5/6 and greater than 3/6 to protect the balance between the gas flow performance and cooling capacity amount and provide the optimization.
[021] The gas flow performance is improved in the cylinder thanks to the production of the protrusion (15) and the outlet orifice (13) within the same form and eccentric position of the protrusion (15) to the outlet orifice (13).