Fluid handling – Systems – Multi-way valve unit
Reexamination Certificate
2006-12-26
2006-12-26
Rivell, John (Department: 3753)
Fluid handling
Systems
Multi-way valve unit
C137S625240, C251S283000, C091S37500R
Reexamination Certificate
active
07152627
ABSTRACT:
A control valve for a hydraulic power steering system includes a pair of flow circuits arranged in parallel. Each flow circuit includes an upstream and downstream flow orifices arranged in series. Each set of orifices defines between the orifices an intermediate pressure zone of the valve. Both orifices close together from a centered condition of the valve and fully close substantially together at a fully closed condition of the valve. The downstream orifice is larger than the upstream orifice when open to minimize the likelihood of cavitation and noise. An equalization passage fluidly connects both intermediate pressure zones to equalize pressure despite variations in orifice size due to manufacturing tolerances. The control valve includes a bypass passage in parallel with the flow circuits. A pressure relief valve in the control valve has a normally closed valving member in the bypass passage that opens the valve in the event of overpressure.
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Danley David M.
Giurlando Kenneth C.
Tippton Jeffrey E.
Hooker & Habib, P.C.
R. H. Sheppard Co., Inc.
Rivell John
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