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t 0.010 in. Cylinder Running Clearance C.9 Vertical Runout Adjustment C.9.1 If it is believed that some adjustment is necessary to the vertical runout readings, it must first be assured that cylinder alignment and cylinder level are properly set so that the components are free of harmful stresses at operating conditions. If crosshead shim adjustment is then considered necessary by interchanging shims under the crosshead shoes, it should be remembered that taking shims from the bottom shoe and placing them under the top nature.com shoe drops the crosshead centerline further below the perfect alignment centerline. This decreases the DROP and thus decreases the positive rod runout at the crosshead, but may actually increase negative runout at the packing case due to sag. This is illustrated on Figure C-5C and in the series of five runout curves of Figures C-6 through C-10. With reference to Figures C-6 and C-9, note that a 0.76 mm (0.030 in.) change of shims, that would put the crosshead and piston on the same centerline such that DROP = 0.00, changes the runout by only 0.076 mm (0.003 in.), that is, the crosshead runout goes to +0.079 mm (+0.0031 in.) from +0.155 mm (+0.0061 in.), and the runout at the packing case goes to -0.056 mm (-0.0022 in.) from +0.020 mm (+0.0008 in.). In other words, for this example, rod runout is changed by only 0.0254 mm (0.001 in.) for each 0.254 mm (0.010 in.) of shims removed from the bottom shoe in an attempt to lower the crosshead closer to the centerline of the cylinder. Because rod length and rod diameter, which affect sag, and cylinder size, which affects running clearance, can significantly affect vertical runout, every compressor cylinder assembly must be fully evaluated for expected vertical runout based on perfect alignment conditions. If crosshead shims are shifted in an attempt to adjust vertical runout, it is important that the crosshead always be installed api download with the "top" side up following removal for maintenance.

RECIPROCATING COMPRESSORS ieee download FOR PETROLEUM, CHEMICAL, AND GAS INDUSTRY SERVICES These illustrations also demonstrate the importance of using the actual me