Patent Application
20070045186
The present invention relates to the field of water filtration systems and more specifically to a system to operate a shut-off valve of a filtration system.
Water filtration systems are used to purify water. For example, a reverse osmosis (RO) system includes an RO membrane. When feed water enters the system, some water goes through the membrane as purified permeate and some is left as concentrate. A shut-off valve can be used to control water flow through the system. For example, the shut-off valve can be placed between the feed line and the permeate line. When the pressure drops in the permeate line, the shut-off valve opens the feed line and water flows though the system. When the pressure rises in the permeate line, the shut-off valve closes and water stops flowing. However, sometimes the shut-off valve does not close all the way and feed water may continue to run to drain.
A filtration assembly includes a feed water line and a permeate line. A shut-off valve is coupled between the permeate line and the feed water line and operative to open the feed line when the faucet is opened based on a pressure differential between the feed line and the permeate line. An energy storage member is located within the permeate line and configured to compress and then expand after the faucet is closed.
In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.
Water filtration system 100 is a filtration assembly generally including a feed water input line 102, a pre-filter 104, a shut-off valve 106, one or more filtration elements 108, 112, a permeate line 120, a concentrate line 114, and a container 122, such as a post-filter. Container 122 can include post-filter elements, such as a carbon filter. Some embodiments omit the post-filter elements from container 122. Permeate outlet line 120 is coupled to faucet 116, which is actuated to allow water to flow through the system.
In this example, filtration elements 108, 112 can include two RO elements connected in series via line 110 for system 100. In other embodiments, a single element can be used or filtration elements 108, 112 can be configured in parallel. Lines 102, 110, 114, and 120 can be hoses, molded passages, pipes, other fluid communication passages, or combinations of any of these. Pre-filter 104 can be a carbon filter and/or a sediment filter to treat the feed water before the water reaches the filtration elements 108, 112. As noted, container 122 can include a carbon filter. In one embodiment, system 100 can include a housing enclosing and housing the elements.
In some embodiments, a high-flux membrane can be used for the RO elements 108, 112 of system 100. A system having a high-flux membrane eliminates the need for a permeate storage tank between elements 108, 112 and the faucet 116. In general, system 100 is configured as a tank-less RO system for home use. In such an environment, feed-line 102 operates under a feed pressure of about 40-80 psi. The entire system is usually fitted beneath a sink or can be enclosed in a housing and located on a counter next to the sink, for example. Other embodiments can utilize a tank if desired.
Shut-off valve 106 is operatively coupled between line 120 and feed water line 102. For example, permeate line 120 can include a branch line 124 to communicate permeate line pressure to the shut-off valve 106. A check valve 130 is located in line 120. Shut-off valve 106 is operative so as to use the pressure differential between permeate line 120 and feed line 114 to regulate flow through the system. Thus, when a user opens faucet 116 the corresponding drop in pressure in line 120 causes shut-off valve 106 to open feed line 102 letting water flow through the shut-off valve and through the elements 108, 112 (
System 100 further includes an energy storage member 200 located within the permeate line 120. In one example, energy storage member 200 is configured to provide an air cushion that helps piston 107 of the shut-off valve 106 complete its movement and fully close the shut-off valve when the faucet is closed. This is needed because the permeate pressure is dependent on flow through the shut-off valve. When the faucet is first closed the pressure in the permeate line is at its highest and the shut-off valve begins to close. However, as the shut-off valve closes the permeate pressure drops and less permeate enters line 120. The permeate pressure's dependency on the feed water flow may not allow the piston 107 to achieve full travel. Therefore, the feed water never fully shuts off and the system continues to run with feed water going to drain.
In contrast, in system 100, when faucet 116 closes, the relatively high permeate pressure squeezes and compresses the energy storage member 200. As the valve 106 closes, the permeate pressure drops until the energy storage member 200 expands to provide pressure to the piston 107 of shut-off valve 106. This expansion then causes the piston 107 to fully close.
In this example, energy storage member 200 is located within container 122. In other embodiments, energy storage member 200 can be located anywhere in the permeate line 120 or branch line 124 between check valve 130 and faucet 116.
In this example, energy storage member is a hollow rubber bladder or pillow member 202 having an internal air pressure of about 5 psi. In other examples, the internal air pressure can be anywhere from about 2 psi to about 10 psi or more. Energy storage member 200 includes an elongate pill-shaped body 210 that is compressible. Member 200 is configured to compress when the faucet is closed and to expand when a pressure in the permeate line reaches a predetermined level.
In this example, member 200 includes an outer thermoplastic elastomer shell 215 having a thickness of about 0.04 inches. The member has a length of about 3.5 inches and a width of about an inch. Ribs 220 can be provided in the member to help it compress and expand.
Referring again to
When faucet 116 is closed (
In other embodiments, other energy storage members can be used for the system discussed above. For example, a diaphragm can be incorporated into permeate line 120 with either an air cushion or a spring behind it. Alternatively, an energy storage member 200 can be formed of a compressible closed-cell foam. Such examples would work as discussed above for energy member 200.
In some embodiments, a container 122 (
It is understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
