GE H301 Series Operating Manual page 113

Performance parameters to check, includes volumetric efficiency, gas
temperatures, driver power limitations, crosshead pin reversals, interstage
pressures, system torsional response, compressor valve dynamics and process gas
acoustical affect. The added cylinder clearance may significantly change process
gas pressures and require valve modifications (usually spring changes) to achieve
optimum valve life for long-term operation.
A S P H Y X I A T I O N
SERVICING OF VVCP'S, IN HAZARDOUS OR TOXIC GAS SERVICE,
CAN HOUSE TRAPPED GAS.
Complies with ANSI Z535, ISO 3864, OSHA 1910.145 (f) (7)
VVCP Adjustment Range
Use the VVCP to adjust a cylinder's HE clearance. The amount of change in
clearance volume varies depending upon the position of the VVCP piston, see
"Figure 20". The expected change in compressor flow and horsepower is a function
of compression ratio and the gas properties.
VVCP adjustment can range from the HE's fixed clearance (VVCP fully closed,
0% travel) to maximum clearance (VVCP fully open, 100% travel). Clearance is
often calculated in cubic inches, VVCP position is commonly communicated to
equipment operators in "inches of travel" as shown in "Table 24". A cross reference
can be found by consulting your HSR compressor operations and parts manual.
H301/302 HSR Compressors | Rev. 2.2 | 103