Patent EA-002256-B1 (EA)
Title: Apparatus and method for the purification of water
Inventor: WISEBURGH PETER
IPC: B01D61/12
Filed: 1998-09-28
Abstract: 1. Domestic apparatus for purifying drinking water, comprising a feed water inlet and a purified water outlet, a filter devicet, wherein comprising prefilter means and microporous membrane filter means interposed between said inlet and said outlet, and means for driving the water through said filter device at a constant flow rate. 2. Apparatus according to claim 1, further comprising means for monitoring the time from the installation of the filter device, means for monitoring the aggregate time during which the water has flowed through the lilter device, and means for preventing the flow of water through the filter device when either of said times has reached a predetermined threshold value. 3. Apparatus according to claim 1, wherein the means for driving the water through the filter device at a constant flow rate comprise means for applying pressure to the filter and means for controlling thc flow rate regardless of changes in pressure. 4. Apparatus according to claim 1, wherein the means for controlling the flow rate comprise a flow restrictor. 5. Domestic apparatus for purifying drinking water according to claim 1, wherein the filter device comprises: 1- an innermost drainage layer; 2- two layers of microporous membrane, symmetrically disposed adjacent to the two sides of said drainage layer; 3- two layers of a prefilter, symmetrically disposed adjacent to the two outer sides of said microporous membrane layers; 4- said microporous membrane layers and said prefilter layers being integrally sealed along a top edge; 5- said drainage layer and said microporous membrane layers being sealed to said prefilter layers at the bottom of these latter; and 6- said microporous membrane layers and said depth filter layers being wider than said drainage layer, and being sealed together along their lateral edges; and the filter device further comprises: a) one or more of such filter elements arranged parallel to one another and perpendicular to a base plate having a central opening and an upper surface, and traversing said central opening thereof with the bottom of their prefilter layers at the level of said base plate upper surface; b) said filter elements being integrally adhered to the base plate by filling with adhesive the space between them and said inner edge of said base plate's central opening; c) said filter elements and base plate being integrally sealed into a fluid pressurizable housing such that the filtered water entering the housing is forced to pass through the filter elements in order to exit from the housing in a filtered state. 6. Method of purifying drinking water, which comprises causing the water to flow at a constant flow rate through a purification filter device comprising prefilter means and microporous membrane filter means. 7. Method according to claim 6, further comprising monitoring the time from the installation of the filter device, monitoring the aggregate time during which the water is flowing through the filter device, and preventing the flow of water through the filter device when either of those times has reached a predetermined threshold value. 8. Method for operating a filter comprised of depth filter and microporous membrane means, which comprises the following steps: I. Operating the filter at an initial constant flow rate until a predetermined total pressure drop across the filter has been reached. II. During the said operation, monitoring and plotting the total throughput is plotted versus the fluid velocity. III. Repeating the above operations at different constant flow rates and with different filter surface areas. IV. Choosing, from the resulting plots, the desired throughput, and reading from the plot, the maximum allowable fluid velocity consistent with said throughput. V. Choosing a filter area, equal to the desired constant flow rate, divided by the maximum fluid velocity.