BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

The invention pertains to the field of valves. More particularly, the invention pertains to wedge gate valves.

DESCRIPTION OF RELATED ART

Gate valves have been used for centuries in water supply systems to control the flow of water or other fluids through pipes. For example, gate valves are often used in fire protection applications to close off water mains. Referring toFIG. 1andFIG. 2, one such wedge gate valve10has a valve body12with a flow passage13between an inlet14and an outlet16, and first and second flanges18,19at the inlet14and the outlet16. The flanges18,19are used to bolt the gate valve10stably to other water supply system components (not shown).

A gate20fits in a gate channel22inside the valve body12. The gate20can be moved into a closed position—fully into the flow passage13from the gate channel22—to block water flow between the inlet14and the outlet16. The gate20can also be moved into an open position—withdrawn somewhat from the flow passage13into the gate channel22—such that water can flow through the valve body12.

When the gate20is moved from the gate channel22to the closed position, a rigid wedge portion24of the gate valve20mates with a sealing surface26that extends semi-annularly from an end of the gate channel22into a portion of the flow passage13. The gate channel22has a width to accommodate a width of the wedge portion24plus some additional clearance. Toward the flow passage13, the width of the gate channel22narrows so that as the gate20moves to the closed position, the wedge portion24abuts and seals against the sealing surface26. The portion of the sealing surface26that extends into the flow passage13is created by a recess or slot28into a perimeter surface30of the flow passage13.

The recess28tapers into the perimeter surface30of the flow passage13. At a corresponding position on the perimeter of the gate20, which is to the gate channel side of a plane that is perpendicular to a center axis32of the gate channel22and that is parallel and intersecting with a center axis34of the flow passage13, the wedge portion24abruptly or sharply transitions to a non-wedge portion36. The non-wedge portion36can have a constant width. A radially outward-facing surface38of the non-wedge portion36abuts against the perimeter surface30of the flow passage13in the closed position to seal the flow passage13. A width of the rigid wedge portion24drives a width of the gate channel22, which must be sized larger than the width of the non-wedge portion36to accommodate the larger width of the wedge portion24. In turn, the size of the wedge portion24and the gate channel22affect the size of other parts and the overall size and weight of the gate valve10. Further, with the sharp transition from wedge portion24to non-wedge portion36, the parts must be manufactured with relatively tight dimensional tolerances in order to yield a reliable and consistent seal.

The gate20is connected to a stem40at a first end42of the stem40, which is moved along the center axis32of the stem40to move the gate20between the open and closed positions. The stem40can be partly or fully threaded. The gate20can be connected to the first end42by a collar or swivel41, which is internally threaded to engage the threaded portion of the stem40, allowing the stem40to rotate and drive the gate20linearly along the center axis32while the gate channel22and wings44engaging a corresponding channel (not shown) in the recess28of the gate20prevent the gate20from rotating. In various embodiments, rotation of the stem40can be driven manually or automatically.

The stem40extends away from the flow passage13and the gate20through the gate channel22to and through a valve cover46, which is mounted on a third flange48at the gate channel22. A seal50is compressed between a flat surface of the valve cover46and the third flange48. The size of the third flange48, which adds additional weight itself to the wedge gate valve10, is sized large enough to accommodate the size of the gate channel22and wedge portion24. Due to the size and weight of the wedge gate valve10, four or more bolts52are required to secure the valve cover46to the flange48.

A seal plate54is bolted to the valve cover46to cover and seal an opening56in the valve cover46over the stem40. Bolts58are used to secure the seal plate54and to compress a seal element60between the seal plate54and the valve cover46to facilitate making a fluid-tight seal there.

SUMMARY OF THE INVENTION

A wedge gate valve is disclosed herein that, compared to conventional wedge gate valves, has a reduced size and weight, improved structural strength, and improved sealing functionality.

In an embodiment, a gate valve includes a valve body, a valve cover, and a cap. The valve body includes a first opening, a second opening, a third opening, a flow passage from the first opening to the second opening, and a gate channel, the gate channel having a first end intersecting the flow passage and a second end delineated by the third opening. The valve cover is configured to fit over the third opening. The cap is configured to cover an opening of the valve cover.

In an embodiment, a valve cover for a gate valve includes a body and a cap. The body has an opening, a first sealing surface around the opening, and a second sealing surface extending around the opening, the second sealing surface protruding from the first sealing surface. The cap is configured to cover the opening, the cap having a third sealing surface configured to mate with the first sealing surface, the cap having a fourth sealing surface configured congruent to the second sealing surface.

In an embodiment, a valve cover cap includes: a body with a wall around an internal hollow and a center axis; a first sealing surface on an end of the wall; a first pin flange extending from a first side of the body; a second pin flange extending from a second side of the body; a first pin hole through the first pin flange; and a second pin hole through the second pin flange, the first pin hole having a first pin hole axis, the second pin hole having a second pin hole axis, the first pin hole axis and the second pin hole axis oriented perpendicular to the center axis.

