HYDRAULICALLY OPERATED ACTUATOR
 Inventors: Joseph A. Burkhardt; Thomas W.
Childers, both of New Orleans, La.;
Harry R. Hanson, Houston, Tex.;
Bobby M. Harkrider, Gretna, La.
 Assignee: Exxon Production Research Co.,
 Appl. No.: 287,004
 Filed: Jul. 27,1981
Related U.S. Application Data
 Continuation of Ser. No. 13,941, Feb. 22, 1979, abandoned.
 Int. C1.3 F15B 13/042
 U.S. Q 91/395; 91/401;
92/152; 92/162 R; 251/62; 277/58; 277/113;
 Field of Search 91/394, 395, 401;
92/152, 162 R; 251/62, 63, 63.5, 63.6, 214;
277/58, 113, 236
 References Cited
U.S. PATENT DOCUMENTS
2,911,952 11/1959 Peras 91/394
3,047,300 7/1962 Taylor 277/236
3,072,104 1/1963 Marsh 91/394
3,238,850 3/1966 Desmarchelier 91/394
3,257,119 6/1966 Bialkowski 277/236
3,507,190 4/1970 Kluczynski et al 91/395
3,654,834 4/1972 Sifri et al 91/401
3,974,910 8/1976 Papai 91/394
4,127,168 11/1978 Hanson et al, 277/236
Primary Examiner—George L. Walton
Attorney, Agent, or Firm—John S. Schneider
A hydraulically operated actuator employs multiple metal-to-metal static seals to isolate the hydraulic fluid and to isolate the actuator from surrounding contaminating (ambient) fluids. A housing contains at least two linearly spaced apart chambers. A piston reciprocates from a retracted position to an extended position (power stroke) and from the extended position to the retracted position (return stroke) in one of the chambers (hydraulic chamber). The hydraulic chamber is separated by the piston into two sections, one of which contains high pressure hydraulic fluid and the other of which contains low pressure hydraulic fluid. A first static metal seal ring unit is designed to seal first at the completion of the power stroke of the piston to isolate the low pressure hydraulic fluid section from external contaminating fluids which may be at a higher pressure. A second static metal seal ring unit is designed to seal at the completion of the return stroke of the piston also to isolate the low pressure section from external contaminating fluids. Power for the return stroke is primarily supplied by springs, with biasing pressure from the external environment providing a lesser contribution. A third static metal seal ring unit may be employed to obtain a simultaneous seal with the first metal seal ring unit to isolate the high pressure section from the low pressure section at the completion of the power stroke of the piston.
37 Claims, 23 Drawing Figures