Patent EA-002799-B1 (EA)
Title: Water dispensing apparatus with filter integrity testing system
Inventor: TANNY GERALD
IPC: G01M3/00
Filed: 2000-04-03
Abstract: 1. Water dispenser, which comprises, in addition to a water container, a filter element contained within a filter housing having an inlet and a dispensing outlet, a source of pressure and first valve and first conduit means for feeding water from said container to said filter housing inlet: a-means for feeding gas to said filter housing inlet to create gas pressure at said inlet; b-a pressure gauge or other transduction means for monitoring the pressure at the filter inlet; and c-control means for controlling said gas feeding means to cause or stop said feeding. 2. Water dispenser according to Claim 1, wherein the means for feeding gas to the filter inlet comprise: a-a reservoir; b-second valve and conduit means for controlling the level of the water in said reservoir; and c-the control means comprise third conduit and valve means for permitting or preventing the admission of water into said reservoir. 3. Water dispenser according to Claim 1, wherein the source of pressure is a compressed gas cylinder provided with valve and conduit means for controlling the admission of compressed gas from said cylinder into said water container, and the means for feeding gas to said filter inlet comprise conduit and valve means for feeding gas to said inlet directly from said gas cylinder. 4. Water dispenser according to Claim 1, comprising, in addition to a water container, a filter element contained within a filter housing having an inlet and a dispensing outlet, a source of pressure and first valve and first conduit means for feeding water from said container to said filter housing inlet: a-a reservoir; b-second valve and conduit means for controlling the level of the water in said reservoir; c-third conduit and valve means for connecting said reservoir to said filter inlet; d-a pressure gauge for monitoring the pressure at the filter inlet; and e-control means for causing said second and third valve and conduit means to permit or prevent the admission of water into said reservoir. 5. Water dispenser according to Claim 2, wherein the source of pressure is a pump. 6. Water dispenser according to Claim 5, wherein the second valve and conduit means connect the reservoir to the pump and/or to the filter housing inlet or disconnect said reservoir from said pump and/or said filter housing inlet. 7. Water dispenser according to Claim 2, wherein the source of pressure is a container of compressed gas and conduit means for controlling the admission of compressed gas from said cylinder into the water container. 8. Water dispenser according to Claim 7, wherein the second valve and conduit means connect the reservoir to the water container when compressed gas has been admitted into it and/or to the filter housing inlet or disconnect said reservoir from said container and/or said filter housing inlet. 9. Water dispenser according to Claim 2, wherein the second valve and conduit means are such as to selectively allow the source of pressure to feed water into the reservoir, whereby to displace air therefrom or to draw water therefrom, selectively to cause water partially to fill said reservoir to a predetermined, normal level or to a higher testing level. 10. Water dispenser according to Claim 2, wherein the third conduit and valve means are such as to permit to introduce, into the filter housing inlet, air displaced by water fed into the reservoir and to displace air and/or water from said filter housing. 11. Water dispenser according to Claim 1, wherein the filter housing is provided, in addition to its dispensing outlet, with a second outlet on the filter inlet side. 12. Water dispenser according to Claim 11, wherein the second outlet is a feedback outlet connected to conduit means for returning, to the water container, water displaced from the filter housing. 13. Water dispenser according to Claim 1, wherein the control means for controlling the gas feeding means are activated to stop said feeding when the pressure at the filter inlet has reached a predetermined test pressure. 14. Water dispenser according to Claim 13, wherein the test pressure is lower than the bubble point pressure of the filter element within the filter housing. 15. Water dispenser according to Claim 13, further comprising an optical or acoustic alarm for signaling if, at the test pressure, bubbles appear at a filter outlet. 16. Water dispenser according to Claim 1, wherein the control means comprise a microprocessor. 17. Water dispenser according to Claim 1, wherein the control means are programmed selectively to place the dispenser in one of the following modes: inactive mode, in which the source of pressure is inactive and all the valve means are closed; dispensing mode, in which the source of pressure is activated and the first valve means are open; and test mode, in which gas is fed to the filter inlet. 18. Water dispenser according to Claim 1, which is a domestic drinking water dispenser. 19. Method for testing the integrity of a filter element contained in a filter housing, in a household drinking water dispensing apparatus, which comprises the following steps: a-feeding gas to the filter inlet from a compressed gas cylinder; b-monitoring the gas pressure at the filter inlet; c-discontinuing the feeding of gas when said pressure has become the test pressure; and d-verifying whether air bubbles appear in the water issuing from a filter outlet, and if they do appear, substituting the filter, while if they do not appear, using the dispensing. 20. Method for testing the integrity of a filter element contained in a filter housing, in a household water dispensing apparatus, which comprises the following steps: providing a reservoir; b-feeding water into said reservoir to a predetermined, normal level; when it is desired to test the filter: c-filling all the pores of the filter element with water; by filtering water through the element in the normal operational mode; d-feeding water into said reservoir to raise the water level therein to a test level, while allowing air contained therein to flow out of said reservoir into the filter housing inlet thereby displacing the water in the inlet side of the filter housing; e-monitoring the air pressure at the filter inlet; f-discontinuing the feeding of water into said reservoir when said inlet pressure has reached a predetermined test pressure sufficient to distinguish the existence of gross mechanical leaks either in the filter element, or allowing bypass to occur between the filter element and the filter housing; and g-verifying whether air bubbles appear in the water issuing from the filter housing outlet, and if they do appear, substituting the filter, while if they do not appear, using the dispensing apparatus in the normal way. 21. Method of operating a water dispenser having an inactive, a dispensing and an integrity test mode, which comprises placing the dispenser in the test mode, carrying out a testing method comprising creating at a filter housing inlet an air pressure lower than the bubble point pressure of the filter element contained within the filter housing, verifying whether air bubbles appear at the filter housing outlet, indicating a faulty filter, substituting the filter if it is found to be faulty, and placing the dispenser back into the inactive or dispensing mode. 22. Water dispenser, which comprises, in addition to a water container, a filter housing having an inlet and a dispensing outlet, a source of pressure and first valve and first valve and conduit means for feeding water from said container to said filter inlet: a)-a reservoir; b)-second valve and second conduit means connecting said reservoir to said source of pressure for selectively feeding water into said reservoir, whereby to displace air therefrom, or for drawing water therefrom, selectively to cause said reservoir to become partially filled to a normal level or to a testing level higher than said normal level; c)-third valve and third conduit means for connecting said reservoir to said filter housing inlet, whereby to introduce into said filter housing inlet air displaced by water fed into said reservoir and to displace water from said filter housing to said outlet thereof; d)-pressure measurement means for monitoring the pressure at the filter inlet; and e)-control means for causing said source of pressure and said second valve and conduit means to discontinue the feeding of water into said reservoir. 23. Water dispenser according to Claim 1, wherein the filter element is chosen from among the group consisting of microporous synthetic membranes, or microporous filters prepared from ceramic materials, metal, or carbon, with a nominal pore size of a value sufficient or smaller than that required to retain 99% or more of cryptosporidium Parvum, giardia Lablia and pseudomonas Aurigena. 24. Water dispenser according to Claim 1, wherein the filter element has a bubble point pressure in the range of. 0.5 bar to 8 bar. 25. Water dispenser according to Claim 1, for domestic use, wherein the water container has a capacity from 0.5 to 5 liters. 26. Water dispenser according to Claim 1, for domestic use, wherein the reservoir has a capacity from 50 cc to 1.5 liter. 27. Water dispenser according to Claim 1, further comprising an electro-optical device for signaling the presence of air bubbles in a water stream issuing from a filter outlet, which comprises a radiation transmitter, a radiation receiver, a radiation transparent window for permitting the transmitted radiation to traverse the water stream, reflecting means for reflecting to said radiation receiver the radiation which has traversed the water stream, a radiation transparent window separating the water stream from said radiation transmitter and said radiation receiver, and electronic means for monitoring the intensity of the radiation received by said radiation receiver and generating a signal if said intensity exceeds a predetermined threshold. 28. Water dispenser according to Claim