Patent ID: 8277653

Claim:
A power recovery chamber for use in a positive-displacement power recovery apparatus for recovering power at a low-pressure liquid side by boosting pressure of low-pressure liquid by transferring pressure of high-pressure liquid to said low-pressure liquid, said power recovery chamber comprising: a cylinder; a piston disposed in said cylinder and capable of being reciprocated in a longitudinal direction of said cylinder; a piston guide disposed in said cylinder and extending in said longitudinal direction of said cylinder for guiding said piston when said piston is reciprocated in said longitudinal direction of said cylinder; cylinder covers for covering both ends of said cylinder, said cylinder and said cylinder covers forming a liquid container; and openings formed in said cylinder or said cylinder covers for allowing said high-pressure liquid and said low-pressure liquid to pass therethrough, respectively; wherein at least a part of an outer circumferential surface of said piston is out of contact with an inner surface of said cylinder installed to form a radial clearance between said piston and said cylinder, creating a contact interface between said low-pressure liquid and said high-pressure liquid in said radial clearance, and said piston is brought into contact with said piston guide at a part where said piston guide passes through said piston.