Abstract: A method for rating the efficiency of a compressed air system is provided comprising, (a) selecting a plurality of efficiency factors, (b) selecting a set of conditions for each efficiency factor, (c) assigning a numerical value to each condition, (d) determining a score for the efficiency factor by comparing the current condition with the preselected conditions and assigning the numerical value associated with the closest preselected condition, and (e) calculating a total efficiency score by adding the scores from the plurality of efficiency factors.

Abstract: A method for rating the efficiency of a compressed air system is provided comprising, (a) selecting a plurality of efficiency factors, (b) selecting a set of conditions for each efficiency factor, (c) assigning a numerical value to each condition, (d) determining a score for the efficiency factor by comparing the current condition with the preselected conditions and assigning the numerical value associated with the closest preselected condition, and (e) calculating a total efficiency score by adding the scores from the plurality of efficiency factors.

Abstract: A lift valve communicating with a compression chamber of a variable capacity screw compressor is set forth including a valve housing, a piston reciprocally received within the valve housing, a shaft having a first end connected to the piston and a second end extending from the housing. The valve further includes a valve element connected to the second end of the shaft having a valve surface exposed to the compression chamber and a reciprocation mechanism for reciprocating the piston within the housing. The reciprocation mechanism includes a first pressure passage communicating with the housing adjacent a side of the piston, and a second pressure passage communicating with the housing adjacent and opposed side of the piston, wherein the valve surface is positively displaced toward and away from the compression chamber of the variable capacity screw compressor in response to the application of fluid pressure to at least one of the first and second pressure passages to vary the capacity of the screw compressor.

Abstract: A lift valve communicating with a compression chamber of a variable capacity screw compressor is set forth including a valve housing, a piston reciprocally received within the valve housing, a shaft having a first end connected to the piston and a second end extending from the housing. The valve further includes a valve element connected to the second end of the shaft having a valve surface exposed to the compression chamber and a reciprocation mechanism for reciprocating the piston within the housing. The reciprocation mechanism includes a first pressure passage communicating with the housing adjacent a side of the piston, and a second pressure passage communicating with the housing adjacent and opposed side of the piston, wherein the valve surface is positively displaced toward and away from the compression chamber of the variable capacity screw compressor in response to the application of fluid pressure to at least one of the first and second pressure passages to vary the capacity of the screw compressor.

Abstract: A lift valve communicating with a compression chamber of a .?.variable capacity.!. screw compressor is set forth including a valve housing, a piston reciprocally received within the valve housing, a shaft having a first end connected to the piston and a second end extending from the housing. The valve further includes a valve element connected to the second end of the shaft having a valve surface exposed to the compression chamber and a reciprocation mechanism for reciprocating the piston within the housing. The reciprocation mechanism includes a first pressure passage communicating with the housing adjacent a side of the piston, and a second pressure passage communicating with the housing adjacent and opposed side of the piston, wherein the valve surface is positively displaced toward and away from the compression chamber of the .?.variable capacity.!. screw compressor in response to the application of fluid pressure to at least one of the first and second pressure passages .?.

Abstract: A lift valve communicating with a compression chamber of a .?.variable capacity.!. screw compressor is set forth including a valve housing, a piston reciprocally received within the valve housing, a shaft having a first end connected to the piston and a second end extending from the housing. The valve further includes a valve element connected to the second end of the shaft having a valve surface exposed to the compression chamber and a reciprocation mechanism for reciprocating the piston within the housing. The reciprocation mechanism includes a first pressure passage communicating with the housing adjacent a side of the piston, and a second pressure passage communicating with the housing adjacent and opposed side of the piston, wherein the valve surface is positively displaced toward and away from the compression chamber of the .?.variable capacity.!. screw compressor in response to the application of fluid pressure to at least one of the first and second pressure passages .?.