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U.S. Department of Energy
Office of Scientific and Technical Information

Viscosity-temperature compensator for hydraulic systems

Patent ·
OSTI ID:6109792

A hydraulic control system is described for use in a sidewall coring tool to control a hydraulic motor used to drive a bit and a ram means for advancing and retracting the bit from the sidewall of a bore hole comprising: a high volume hydraulic system having first conduit means for connecting a hydraulic pump to a hydraulic motor used to drive a bit and second conduit means for connecting the hydraulic motor to a reservoir for the hydraulic fluid, wherein, there is a pressure drop when hydraulic fluids flow through the first and second conduit means, a low volume hydraulic system connected to a hydraulic ram means for advancing or retracting the bit, a control valve comprising a housing having a first and second chambers separated by a partition, a piston in the first chamber movable between a first position and a second position, with the second position being closer to the partition, and with the piston being in sealing relationship with the interior surface of the first chamber for the purpose of separating the first chamber into two compartments, a means urging the piston away from the partition, an orifice in the second chamber, a means connected to the piston and extending through the partition in sealing relationship with the partition for adjusting the flow of fluid through the orifice; a backpressuring means for providing a pressure through the bleed port substantially equal to the pressure drop in the first conduit means and the second conduit means in the high volume hydraulic system.

Assignee:
Amoco Corp., Chicago, IL
Patent Number(s):
US 4685294
OSTI ID:
6109792
Country of Publication:
United States
Language:
English