General Electric, Large Steam Turbine, Electrohydraulic fluid systems currently utilize either Vickers or Dennison High Pressure Fluid Pumps. These pumps which were supplied with the original Hydraulic Power Unit and are very slow to respond to system demand. This slow response (1-3 seconds from no flow to full flow) causes many problems with the Turbine control system. The most pronounced problems occur during valve test with major swings in manifold pressure. These pressure swings could even cause the turbine to trip.
Many utility stations who currently have these pumps on their units have been experiencing problems as the pumps begin to show signs of age. General Electric distributed a TIL (Technical Information Bulletin) #1115-3R1 in 1992 that stated the Vickers PV2032 and PV2050 hydraulic pumps have been discontinued by the manufacturer. The Dennison PVO9XS-032 and 053 hydraulic pumps were noted to be available through 1997..
NovaTech in conjunction with Rexroth (the worlds largest supplier of hydraulic components) offers a replacement kit for both the Vickers and Dennison hydraulic pumps.
NovaTech Corporation, 328 South Link Lane, Suite 13, Ft. Collins, CO 80524. Tel: 970-224-2223; Fax: 970-224-1700.