Page 65 - Reciprocating Compressors Operation Maintenance
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52 Reciprocating Compressors: Operation and Maintenance
options are similar to those in low and medium pressure cylinders. Pres-
sure range is from 1000 psi to 2500 psi, depending on the bore sizes.
High-Pressure Cylinders
High-pressure cylinders, as shown in Figure 2-9, are made from a steel
forging, with only nominal water cooling as compared to the other cylin-
ders. Because the smallest possible number of openings in the forging is
desired, capacity control mechanisms are not normally provided. Tie
bolts may be installed perpendicular to the bore to pre-stress the forging,
decreasing the maximum tensile stress induced by the gas pressure. Valve
ports are finished to a highly polished surface, which reduces the maxi-
mum tensile stresses. The pressure range for these cylinders is approxi-
mately 2000 psi to 8000 psi.
FIGURE 2-9. Forged steel high-pressure cylinder (Source: Dresser-Rand,
Painted Post, New York).
High-Pressure, Low-Differential Pressures
This type of cylinder, Figure 2-10, is commonly called a recycle cylin-
der. It generally uses a "tail rod" because it is normally difficult to obtain
reversible frame loading with a conventional piston rod design. An addi-
tional packing assembly is required. Made from steel forging, the cylin-
der has a cover pressure range from 2000 psi to 8000 psi.
