초록 ▼

In a lubricant-cooled gas compressor (10) the temperature of separated lubricant returned to the air-side (11) is monitored by a thermostatically controlled restrictor valve (22) which minimises the flow of returned lubricant when temperature is low as on start up or when running on reduced load but

In a lubricant-cooled gas compressor (10) the temperature of separated lubricant returned to the air-side (11) is monitored by a thermostatically controlled restrictor valve (22) which minimises the flow of returned lubricant when temperature is low as on start up or when running on reduced load but increases the flow as the lubricant temperature increases. This will minimise he condensation of water from indrawn air when the temperature of the compressed air is too low to retain the water as vapour, so that the returned lubricant is contaminated with water which will damage the moving components of the air-end.

대표청구항 ▼

The invention claimed is: 1. A lubricant-cooled gas compressor (11) adapted to discharge a mixture of lubricant and compressed gas and provided with means (13) for separating the lubricant downstream of the compressor (11) and with a return line (16) for returning the separated lubricant to the com

The invention claimed is: 1. A lubricant-cooled gas compressor (11) adapted to discharge a mixture of lubricant and compressed gas and provided with means (13) for separating the lubricant downstream of the compressor (11) and with a return line (16) for returning the separated lubricant to the compressor (11), characterized in that the return line (16) is controlled by a restrictor valve ( 22) which is mechanically operated by a thermostat (37, 38) immersed in lubricant in the return line (16), the arrangement being such that the return flow of lubricant to the compressor (11) is restricted when the temperature of the lubricant falls and is increased when the temperature of the lubricant rises; the compressor (11) characterized in that the restrictor valve (22) comprises a housing (30) having a lubricant inlet (32) and a lubricant outlet (33), the outlet communicating with an annular chamber (34) within the housing ( 30) which is coaxial with, intermediate the ends of and of greater diameter than a bore (31) within the housing communicating with the inlet (32), a sleeve (35) moveable axially of the bore (31) whereby an opening (36,36A) in the wall of the sleeve (35) may be brought into or out of register with the chamber (34) and the thermostat is a thermostatic device (37 ,38) within the bore (3l) which will respond to changes in the temperature of lubricant passing through the housing (30) thereby to displace the sleeve (35) to vary the area of said opening (36,36A) which is exposed to the chamber (34) . 2. A compressor as claimed in claim 1, characterized in that the thermostatic device comprises a cylinder (37) moveable with the sleeve (35), a piston (38) fixed at one end relative to the housing (30) and a wax within the cylinder (37) at the free end of the piston (38), the wax being of the kind which increases in volume as it liquefies in response to an increase in temperature. 3. A compressor as claimed in claim 1 characterized in that a by-pass means (40) is provided by bypassing the thermostat ( 37,38), the by-pass means being adapted to ensure a minimum return flow of lubricant to the compressor (11) independently of the thermostat (37,38). 4. A compressor as claimed in claim 3 characterized in that the by-pass means comprises a by-pass duct (40) within the housing (30) which directly communicates the inlet (32) with said chamber (34). 5. A compressor as claimed in claim 4, characterized in that the by-pass duct (40) has a restriction (41). 6. A compressor as claimed in claim 5, characterized in that the restriction (41) is adjustable. 7. A retro-fit device (22) for incorporation in a lubricant-cooled compressor (10), the compressor being of the kind which discharges a mixture of lubricant and compressed gas, means ( 13) being provided for separating the lubricant from the compressed gas downstream of the compressor (11) and a return line (16) for returning the separated lubricant to the compressor (11) and a return line (16) for returning the separated lubricant to the compressor (11), characterized in that the device (22) comprises a housing (30) having an inlet (32) and an outlet (33) whereby it may be incorporated in the return line (16), a bore (31) between the inlet (32) and the outlet ( 33), a thermostatically controlled restrictor valve (35) within the bore (31) located so that a temperature sensitive element of the thermostat (37,38) is exposed, in use, to the temperature of lubricant flowing between the inlet (32) and outlet(33), the valve comprising a sleeve (35) moveable in the bore (31) by the thermostat (37,38) whereby an opening (36,36A) in the sleeve will control the outlet ( 33) and restrict said flow when said temperature falls and increase said flow when said temperature increases. 8. A device as claimed in claim 7, characterized in that the outlet (33) communicates with a cylindrical chamber (34) within the housing (30) which is coaxial with, intermediate the ends of and of greater diameter than said bore (31), the sleeve (35) being movable axially of the bore (31) whereby said opening (36,36A) in the wall of the sleeve (35) may be brought into or out of register with the chamber (34), the thermostat (37,38) being responsive to changes in the temperature of lubricant passing through the bore (31) thereby to displace the sleeve to vary the area of said opening (36,36 A) which is exposed to the chamber (34). 9. A device as claimed in claim 8 characterized in that a by-pass duct (40) is provided in the housing (30) which directly communicates the inlet (32) with said chamber (34). 10. A device as claimed in claim 9, characterized in that the by-pass duct (40) has a restriction (41). 11. A compressor as claimed in claim 10, characterized in that the restriction (41) is adjustable.