Patent ID: 7550088
Filing Date: 2009-06-23
Classification: B01D,C02F,F04B,F04F,Y02A

Abstract:
1. A method of continuously desalinating water by reverse osmosis, comprising: introducing salt water under a first pressure by means of a delivery pump into a pressure compensating device having a piston/cylinder device with a salt water chamber and a concentrated salt water chamber, introducing salt water from the salt water chamber of the pressure compensating device at a second increased pressure into a salt water chamber of a membrane module and separated therein by means of a membrane into desalinated water and concentrated salt water, discharging the concentrated salt water from salt water chamber of the membrane module at approximately the second pressure, introducing the concentrated salt water under approximately the second pressure into the concentrated salt water chamber of the pressure compensating device, wherein the concentrated salt water introduced into the concentrated salt water chamber of the pressure compensating device acts with approximately the second pressure on the salt water introduced into the salt water chamber of the pressure compensating device and acts on the salt water introduced into the membrane module, and maintaining a continuous flow of the salt water over a surface of the membrane in the membrane module by means of salt water discharged from a piston reservoir having a pressure chamber, an outlet chamber, an inlet chamber and a piston, the piston having a front side facing the inlet chamber and a rear side having a first portion facing the outlet chamber and a second portion facing the inlet portion, each one of the front side of the piston and the first portion and the second portion of the rear side of the piston having a respective surface area, the inlet chamber connected to the salt water chamber of the pressure compensating device and the salt water chamber of the membrane module, the outlet chamber connected to a concentrated salt water outlet of the membrane module, and the pressure chamber connected to a pressure reservoir, and applying an assisting pressure from the pressure reservoir to the pressure chamber, wherein the respective surface areas front side of the piston and the first portion and the second portion of the rear side of the piston have ratios such that the assisting pressure helps to produce at predetermined moments in time a respective pressure, which is greater than the second pressure of the salt water discharged from the pressure compensating device, in the inlet chamber.