FIELD OF THE INVENTION

This invention generally relates to pilot operated water valves, and more particularly to systems and methods to reduce bleed hole clogs in diaphragm inserts and water valves incorporating same.

BACKGROUND OF THE INVENTION

Pilot operated water valves use passageways to allow water to flow to separate chambers formed by a diaphragm inside the water valve's internal cavity to aid in opening and closing of the water valve. Because water in an outlet chamber on one side of the diaphragm is pressurized at the same pressure as that of the water in an inlet chamber on the other side of the diaphragm, and assuming the pressure of the valve outlet is less than that of the inlet chamber, the combined effect is to keep the diaphragm seated against the main valve seat to keep the valve closed.

In order to open the pilot operated water valve, a pilot passageway leading from the outlet chamber to the valve outlet is opened by a small solenoid lifting the sealing member exposing the pilot passage. The water in the outlet chamber then proceeds to evacuate from the outlet chamber through the pilot passageway to the outlet. While water will flow into the outlet chamber due to the pressure differential on either side of the diaphragm, the rate at which water is evacuated through the pilot passageway exceeds the ability of the water to refill the outlet chamber, the pressure in the inlet chamber will exceed that of the pressure in the outlet chamber. This pressure differential thus causes the diaphragm to unseat from the main valve seat, thereby fully exposing the opening surrounded by the main valve seat to the inlet chamber. This results in a full opening of the water valve allowing water to flow from the inlet chamber to the outlet.

To close the pilot operated water valve, the pilot passageway is closed when the sealing member closes the pilot passage by de-energizing the solenoid. Water from the inlet chamber flowing through the diaphragm via the passageways then accumulates in the outlet chamber at the pressure of the inlet. This results in a pressure differential across the diaphragm that aids in closing the valve.

As should now be clear, proper operation of the pilot operated water valve requires that water be able to freely flow through the passageways of the diaphragm. That is, if the passageway from the inlet chamber to the outlet chamber becomes clogged, the water valve will not be able to operate properly.

Unfortunately, most pilot operated water valves use a bleed hole as the passageway through the diaphragm between the inlet chamber and the outlet chamber. Molded diaphragm inserts presently have a center hole forming the pilot passageway and a single bleed hole that forms the passageway to allow water to enter the outlet chamber to equalize pressure across the diaphragm as discussed above. However, the bleed hole may become clogged. Bleed hole clogs can be caused by a number of issues, including contaminants in the water, a phenomenon known as window-paning, etc. Window-paning occurs when water in a water valve is allowed to dry and leftover minerals form a skin over the bleed hole. Such clogs are a problem as they prevent water from entering the outlet chamber, causing the valve to operate incorrectly.

In order to reduce the likelihood of such bleed hole clogs, manufacturers of pilot operated water valves began using multiple bleed holes to reduce the chances of having a single bleed hole clog cause malfunction of the valve. The thought with having multiple bleed holes is that if one bleed hole gets clogged, then there is at least one other bleed hole to allow the flow of water across the diaphragm. However, if there are contaminants in the water that cause a clog in one bleed hole, it is likely that all the bleed holes will become clogged eventually.

In many pilot operated water valves, a rigid insert is used along with the diaphragm. In some of these valves, when the valve is closed, the diaphragm contacts the sides and/or upper edge of the insert, and the bleed holes through the diaphragm communicate with the outlet chamber via bleed slots formed in the side and/or bleed holes in the upper edge of the insert. This allows the bleed holes in the diaphragm to be larger to reduce clogging risk therein, while the size of the bleed slots and/or bleed holes regulate the water flow between the inlet chamber and the outlet chamber. Unfortunately, there is still a high likelihood of clogs because contaminants in the water can build up in the bleed slots and/or in the bleed holes in the upper edge of the insert for the same reasons discussed above.

Therefore, there is still a need in the art for a pilot operated water valve having a diaphragm and diaphragm insert that is able to clear out contaminants from passageways to prevent clogs. Embodiments of the present invention provide such a pilot operated water valve having self-cleaning water passageways that enable continued operation of the pilot operated water valve despite the presence of contaminates in the water. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

BRIEF SUMMARY OF THE INVENTION

In view of the above, embodiments of the present invention provide a new and improved pilot operated water valve having a self-cleaning water passageway that overcomes one or more of the problems described above. More particularly, embodiments of the present invention provide a new and improved self-cleaning water passageway in a pilot operated water valve that substantially reduces bleed hole clogs that may lead to valve failure. Still more particularly, embodiments of the present invention provide a new and improved self-cleaning water passageway that creates a self-cleaning action to dislodge any contaminants from the bleed slot. Still more particularly, embodiments of the present invention provide a new and improved self-cleaning water passageway that creates a wiping action that clears away any contaminants in the water passageway. In certain embodiments the new and improved self-cleaning water passageway terminates in a bleed hole formed by a scallop in an upper edge of the insert cooperating with the diaphragm itself when closed. When opened, the scallop and the diaphragm separate to allow clearance of any trapped debris that would otherwise operate to cause failure in a pilot operated water valve.

In one aspect, the invention provides a pilot operated water valve incorporating the self-cleaning water passageway that includes an insert with a bleed slot, preferably a tapered bleed slot with a large bottom and a narrower top. In embodiments having tapered bleed slots, the increasing taper of the bleed slot allows in-rushing water to accelerate as it moves towards to narrower top of the bleed slot. This increases the force with which the water exits through a bleed hole, which is located at the top of the bleed slot, causing the water to flush out any contaminants that may have become stuck in the bleed hole.

In another aspect, the invention provides a pilot operated water valve incorporating the self-cleaning water passageway includes a diaphragm with an unrolling feature. The unrolling feature of the diaphragm creates a two-step cleaning process. The first cleaning step is a self-cleaning action. Once the armature is activated, the water pressure against the diaphragm will cause it to lift and begin the unrolling action. As the diaphragm lifts, the insert will begin to lift above the diaphragm as it is unrolled from contact with the side of the insert. As it does so, part of the passageways in the insert are now exposed to the water in the outlet chamber. This exposure allows any contaminants that had become lodged therein to be flushed out of the passageway and free to exit through the pilot passageway in the insert.

By utilizing the unrolling feature of the diaphragm, the second cleaning step is a wiping action during the valve closing process. Once the armature is deactivated, the pilot passageway is closed and water flows through the passageways and into the outlet chamber. As the diaphragm rolls up and closes, the wiping action as the water accelerates through the passageways between the diaphragm and insert again clears away any contaminants in the passageway.

In yet another aspect, the invention provides a pilot operated water valve incorporating the self-cleaning water passageway that includes a bleed hole formed by an internal wall of the diaphragm contacting a scallop located at the top of a bleed slot, on the upper edge of the insert. This allows the two halves or portions of the bleed hole to be separated and to open the bleed hole for cleaning. In the case that a bleed slot is not powerful enough to flush out a bleed hole clog, separating the two halves or portions of the bleed hole will allow the clog to be cleared out.

Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

