Pressure exchanger with an anti-cavitation pressure relief system in the end covers

A pressure exchanger for transfer of pressure energy from a high pressure liquid to a low pressure liquid, said pressure exchanger comprising:

• a housing having a body portion;
• first and second end plates at opposite ends of the body portion, the end plates each having an inlet aperture and an outlet aperture for respective liquid flow;
• and
• a rotor arranged for rotation in the body portion of the housing and in substantially sealing contact with the end plates at a liquid seal therebetween, said rotor having at least one channel therein extending substantially longitudinally from one end of the rotor to an opposite end of the rotor, the channel having an opening in each end of the rotor;
• a first pair of the apertures of the first and second end plates, aligned with one another for hydraulic communication through the channel and forming a pair of apertures for high pressure liquids, and a second pair of the apertures of the first and second end plates, aligned with one another for hydraulic communication through the channel and forming a pair of apertures for low pressure liquids;
• the channel of the rotor being positioned in the rotor for hydraulic communication with the high pressure pair of apertures and thereafter with the low pressure pair of apertures, such that the channel alternately is in hydraulic communication with liquid under high pressure and thereafter with liquid under low pressure during rotation of the rotor;
• and
• one or more grooves in said end plates, said grooves being positioned to provide hydraulic communication between the openings of the channels and the liquid seal between the rotor and the end plates.

A pressure exchanger for transfer of pressure from a high pressure liquid to a low pressure liquid, said pressure exchanger comprising:

• a housing having a body portion;
• first and second end plates at opposite ends of the body portion, the end plates each having an inlet aperture and an outlet aperture for respective liquid flow, the apertures in one end plate being aligned with the apertures in the other end plate;
• and
• a rotor arranged for rotation in the body portion of the housing and in substantially sealing contact with the end plates at a liquid seal, said rotor having at least one channel therein extending substantially longitudinally from one end of the rotor to an opposite end of the rotor, the channel having an opening in each end of the rotor,
• a first pair of the apertures of the first and second end plates, aligned with one another for hydraulic communication through the channel and forming a pair of apertures for high pressure liquids, and a second pair of the apertures of the first and second end plates, aligned with one another for hydraulic communication through the channel and forming a pair of apertures for low pressure liquids;
• the channel of the rotor being positioned in the rotor for hydraulic communication with the first pair of apertures and thereafter with the second pair of apertures such that the channel alternately is in hydraulic communication with liquid under high pressure and thereafter with liquid under low pressure during rotation of the rotor;
• and
• an anti-cavitation structure in the end plates to provide a pressure change in said channel while the channel is blocked by the end plates.

A pressure exchanger for transfer of pressure energy from a high pressure liquid to a low pressure liquid, said pressure exchanger comprising:

• a housing having a cylindrical body portion;
• first and second end plates at opposite ends of the cylindrical portion, the end plates each having two apertures, one for high pressure liquid and one for low pressure liquid, the high pressure aperture of one end plate being aligned with the high pressure aperture of the opposite end plate, and the low pressure aperture of one end plate being aligned with the low pressure aperture of the opposite end plate;
• and
• a cylindrical rotor arranged for rotation in the cylindrical body portion of the housing and in substantially sealing contact with the end plates at liquid seals, said rotor having one or more channels therein extending substantially longitudinally from one end of the rotor to an opposite end of the rotor, the channel having an opening in each end of the rotor,
• the channels being positioned in the rotor for alternate hydraulic communication with both of the high pressure apertures and thereafter with both of the low pressure apertures, such that each channel alternately is in hydraulic communication with liquid under high pressure and thereafter with liquid under low pressure during rotation of the rotor;
• and
• one or more grooves in said end plates, said grooves joining openings of the channels with the liquid seals being between the rotor ends and the end plates, and each said groove being recessed into each said end plate.

A seawater reverse osmosis system comprising a reverse osmosis cell and a pressure exchanger, the reverse osmosis cell receiving pressurized sea water from the pressure exchanger, separating the pressurized sea water into a low solids content product portion and a high solids content effluent portion, said high solids content effluent portion being at a high pressure, said pressure exchanger receiving the high solids content effluent from the seawater reverse osmosis cell, and transferring the pressure of the effluent to seawater feed, said pressure exchanger comprising:

• a housing having a body portion;
• first and second end plates at opposite ends of the body portion, the end plates each having an inlet aperture and an outlet aperture for respective liquid flow, the high pressure liquid apertures of the first end plate being aligned with the high pressure liquid apertures of the second end plate, and the low pressure liquid apertures of the first end plate being aligned with the low pressure liquid apertures of the second end plate;
• and
• a rotor arranged for rotation in the body portion of the housing and in substantially sealing contact with the end plates at liquid seals, said rotor having at least one channel therein extending substantially longitudinally from one end of the rotor to an opposite end of the rotor, said one channel having an opening in each end of the rotor;
• said one channel of the rotor being positioned in the rotor for hydraulic communication with the aperture pairs, such that the channel alternately is in hydraulic communication with liquid under high pressure and thereafter with liquid under low pressure during rotation of the rotor;
• and
• one or more grooves in said end plates, said one groove overlaying the opening in said one channel at one end of the rotor to bleed pressure therefrom and said one groove being recessed into the one end plate from the one rotor end.