Patent Description:
<CIT>, assigned to the assignee of the invention disclosed hereinbelow, describes a liquid discharge valve, configured for high flow and discharging of liquid at high pressure. The valve is described with reference to <FIG> and <FIG>.

In <FIG>, a liquid discharge valve <NUM> includes a housing <NUM> with an inlet port <NUM>, which can be coupled to a liquid line <NUM> (shown in broken lines), and a liquid outlet port <NUM>. The liquid outlet port <NUM> extends from the housing and can be coupled for returning any liquids flushed therethrough to the liquid system, or for disposing elsewhere.

An inlet chamber <NUM> includes a pressure responsive closing mechanism <NUM> disposed between inlet port <NUM> and liquid outlet port <NUM>. The closing mechanism <NUM> is configured for selectively opening a liquid flow path <NUM> between inlet port <NUM> and liquid outlet port <NUM>. A control chamber <NUM> is in flow communication with the inlet chamber <NUM> via a restricted fluid passage <NUM>. In the prior art, fluid passage <NUM> is always open.

A gas operated valve <NUM> is in fluid communication with the control chamber <NUM>. A discharge pilot valve <NUM> is in fluid communication with the control chamber <NUM>.

The closing mechanism <NUM> is configured to be normally disposed at its closed position so as to prevent liquid flow from the inlet port <NUM> to the liquid outlet port <NUM>. The gas operated valve <NUM> at its closed position is configured for preventing liquid flow through a fluid outlet port <NUM>. In the event of pressure decrease within the control chamber <NUM>, the closing mechanism <NUM> displaces into its open position, thereby permitting liquid flow along the flow path <NUM> between the inlet port <NUM> and the liquid outlet port <NUM>.

The pressure responsive closing mechanism <NUM> includes a plunger assembly <NUM> which is axially displaceable between an uppermost, open position and a lowermost, closed position. The always-open fluid passage <NUM> extends through the plunger assembly <NUM> of the closing mechanism <NUM>. A rolling membrane <NUM> is clamped at one end thereof <NUM> to the plunger assembly <NUM> and at another end thereof <NUM> it is clamped to a portion fixed within inside walls of the housing. The membrane <NUM> is a flexible sealing member and divides the housing into the inlet chamber <NUM> and the control chamber <NUM>.

A liquid drainage port <NUM> may extend between the control chamber <NUM> and the inlet chamber <NUM> to allow liquid to drain from control chamber <NUM> back to liquid line <NUM>.

The gas operated valve <NUM> includes a housing <NUM> fixedly coupled to the housing <NUM>, and a fluid inlet <NUM> that extends into and which is in flow communication with the control chamber <NUM>.

The housing <NUM> has a fluid through-flow aperture <NUM> communicating with an outlet <NUM> and a valve seat formed in housing <NUM> that bounds aperture <NUM>. A flexible closure membrane <NUM> is secured at one end <NUM> to housing <NUM> and at a second end <NUM> to a float member <NUM> disposed within the housing <NUM>. The float member <NUM> is axially displaceable between a lowermost, open position and an uppermost, closed position under buoyant pressure. At the closed position, the closure membrane <NUM> presses against the valve seating so as to seal aperture <NUM>.

The through-flow aperture <NUM> may have a first outlet aperture 96A of substantially elongated slit-like shape, and may communicate at one end thereof with a second outlet aperture 96B, which is substantially greater in area than the first aperture 96A.

The displacement of the float member <NUM> from the closed position to the open position progressively detaches successive linear transverse portions of the closure membrane <NUM>, initially from the first outlet aperture 96A and subsequently from the second outlet aperture 96B, whereas displacement of float member <NUM> from the open position to the closed position, allows for the closure membrane <NUM> to become sealingly biased against the outlet apertures and seal the valve seating. At a bottom end of the float member <NUM> there is a one way valve <NUM> in the form of a sealing disc configured for bearing against sealing shoulders of the fluid inlet <NUM> for sealing thereof; this prevents fluid ingress into the control chamber <NUM> when the gas operated valve <NUM> is at its open position.

The discharge pilot valve <NUM> is coupled to the housing <NUM> with an inlet port <NUM>. An inlet fluid flow path <NUM> extends into the control chamber <NUM>. The cross-sectional area of the inlet fluid flow path <NUM> (A1) is greater than that of the restricted fluid passage <NUM> (A2).

The discharge pilot valve <NUM> is configured with a discharge port <NUM> and a sealing shoulder <NUM> disposed between the inlet port <NUM> and the discharge port <NUM>. A sealing plunger <NUM> is configured at one end thereof with a sealing member <NUM> configured for bearing against the annular sealing shoulder <NUM> in a sealing fashion, with an opposite end of the plunger <NUM> being biased by a compression spring <NUM>. The plunger is thus displaceable between a normally closed position, wherein the sealing member <NUM> sealingly bears against the sealing shoulder <NUM>, and an open position wherein the sealing member <NUM> is disengaged from the sealing shoulder <NUM>, so as to relieve pressure from the control chamber <NUM>.

Accordingly, the discharge pilot valve <NUM> is a pressure relief valve configured for opening at a predetermined pressure threshold. This pressure threshold is controllable through manual governing the compression force of the coiled spring <NUM> by rotating the cap <NUM> (or a bolt in <FIG>), thereby tensioning or releasing the spring.

<FIG> illustrates another version of the liquid discharge valve <NUM>. In this version, a discharge pilot valve <NUM> has a tube <NUM> that is coupled to inlet <NUM> at a coupling port <NUM> and to a control chamber of the discharge pilot valve <NUM> at an additional port <NUM>.

In this arrangement, the inlet <NUM> and the control chamber of the discharge pilot valve <NUM> are at the same pressure. This eliminates or substantially reduces hammering, thereby providing stable operation of the discharge pilot valve <NUM>.

A further valve relevant to the method of claim <NUM> is known from <CIT>.

The present invention seeks to provide an improved a controlled closing system for a hydraulic valve, such as a liquid discharge valve, as described more in detail hereinbelow. The controlled closing system will be described for a valve of the type shown in <FIG> or <FIG>, but the invention is not limited to this type of valve.

There is thus provided in accordance with an embodiment of the present invention a valve with a controlled closing system including a housing having an inlet port, a liquid outlet port, an inlet chamber, a pressure responsive closing mechanism disposed between the inlet port and the liquid outlet port and configured for selectively opening a liquid flow path therebetween, a control chamber in fluid communication with the inlet chamber via a fluid passage, a gas operated valve in fluid communication with the control chamber and with an outlet aperture, wherein the closing mechanism is configured to be displaced into an open position to permit liquid flow along the flow path between the inlet port and the liquid outlet port, and wherein the fluid passage includes a controlled closing system for controlling opening and closing of the fluid passage, the controlled closing system including a seal movable with respect to and sealable against an opening of the fluid passage.

Reference is now made to <FIG>, which illustrates a controlled closing system for a hydraulic valve liquid discharge valve, constructed and operative in accordance with a non-limiting embodiment of the present invention. For ease of understanding, the description follows for the valve <NUM> of <FIG>; like elements are designated by like reference numerals. However, the invention is not limited to this valve and can be carried out with other hydraulic valves.

In the prior art, the restricted fluid passage <NUM> is always open. In contrast to the prior art, in the present invention, the restricted fluid passage <NUM> is not always open. Instead, a controlled closing system is provided that controls opening and closing of fluid passage <NUM>, as is described below.

In one embodiment of the invention, the controlled closing system includes a seal <NUM> movable with respect to and sealable against an opening <NUM> of fluid passage <NUM>, the opening <NUM> facing inlet <NUM>. The opening <NUM> may be the lower opening of the fluid passage <NUM>, or alternatively as in the illustrated embodiment, the opening <NUM> is at the lower end of a tube <NUM> mounted in the existing fluid passage <NUM>, so that tube <NUM> becomes the fluid passage of the system of the invention.

Seal <NUM> may be spherical as shown, or alternatively may be oblong, ellipsoid or other shapes. Seal <NUM> is free to move axially (up and down) in a bore <NUM> of a seal housing <NUM>. Seal <NUM> is preferably denser than the liquid entering the inlet <NUM>.

The operation of the system is now described with reference to <FIG>.

In <FIG>, the movable seal <NUM> does not seal against the fluid passage (that is, either the tube <NUM> or the fluid passage <NUM>), which is between inlet chamber <NUM> and control chamber <NUM>. The plunger assembly <NUM> of the pressure responsive closing mechanism <NUM> seals against the inlet <NUM> of valve <NUM>. The float member <NUM> of gas operated valve <NUM> does not press closure membrane <NUM> to seal against outlet aperture <NUM> of gas operated valve <NUM>, so that air entering the inlet <NUM> of the valve <NUM> can rise and flow past (around) seal <NUM> through the fluid passage <NUM> (or <NUM>) between the inlet chamber <NUM> and the control chamber <NUM>, flow past the float member <NUM> and flow out the outlet aperture <NUM> of the gas operated valve <NUM> to the outside environment.

In <FIG>, the pressure in the inlet chamber <NUM> is greater than the atmospheric pressure which is the pressure in the control chamber <NUM>. This pressure difference causes the plunger assembly <NUM> of the pressure responsive closing mechanism <NUM> to rise and allow liquid (water) and gas (air) to enter the inlet <NUM>, which causes the movable seal <NUM> of the closing system to rise and seal against the fluid passage <NUM> (or <NUM>) between the inlet chamber <NUM> and the control chamber <NUM> of the valve <NUM>. This also causes the float member <NUM> of the gas operated valve <NUM> to press the closure membrane <NUM> to seal against the outlet aperture <NUM> of the gas operated valve <NUM>, so that air entering the inlet <NUM> of the valve <NUM> does not flow out the outlet aperture <NUM> of the gas operated valve <NUM> and fluid entering the inlet <NUM> can flow out of the liquid outlet port <NUM>.

In <FIG>, fluid has entered the control chamber <NUM> above the rolling membrane <NUM>, so that the pressure in the control chamber <NUM> is the same pressure in the inlet chamber <NUM>. However, the area above the membrane <NUM> is greater than the area below the membrane <NUM>. This difference in area causes the plunger assembly <NUM> of the pressure responsive closing mechanism <NUM> to descend. The movable seal <NUM> of the closing system still seals against the fluid passage <NUM> (or <NUM>) between the inlet chamber <NUM> and the control chamber <NUM> of the valve <NUM>. In contrast with the prior art, this slows the descending movement of the plunger assembly <NUM> of the pressure responsive closing mechanism <NUM>.

In <FIG>, the plunger assembly <NUM> of the pressure responsive closing mechanism <NUM> has finished its descent and seals the inlet <NUM> of the valve <NUM>. As soon as fluid cannot flow anymore to the liquid outlet port <NUM>, the seal <NUM> immediately drops to open the fluid passage <NUM> (or <NUM>) and the valve <NUM> is ready for air to enter the valve inlet <NUM> and return to the configuration of <FIG>.

Thus, the movable seal <NUM> of the closing system provides a slower and more controlled closure of the fluid passage between the inlet chamber <NUM> and the control chamber <NUM> and yet provides an immediate response to closure of the valve inlet <NUM> to return to the initial operative configuration.

Claim 1:
A method of using a valve (<NUM>),
wherein said valve (<NUM>) comprises:
a housing (<NUM>) having an inlet port (<NUM>), a liquid outlet port (<NUM>), an inlet chamber (<NUM>), a pressure responsive closing mechanism (<NUM>) disposed between said inlet port (<NUM>) and said liquid outlet port (<NUM>) and configured for selectively opening a liquid flow path (<NUM>) therebetween, a control chamber (<NUM>) in fluid communication with said inlet chamber (<NUM>) via a fluid passage (<NUM>, <NUM>), a gas operated valve (<NUM>) in fluid communication with said control chamber (<NUM>) and with an outlet aperture (<NUM>), wherein said closing mechanism (<NUM>) is configured to be displaced into an open position to permit liquid flow along said flow path (<NUM>) between said inlet port (<NUM>) and said liquid outlet port (<NUM>); and
wherein said fluid passage (<NUM>, <NUM>) comprises a controlled closing system for controlling opening and closing of said fluid passage (<NUM>, <NUM>), said controlled closing system comprising a seal (<NUM>) movable with respect to and sealable against an opening (<NUM>) of said fluid passage (<NUM>, <NUM>);
and comprising a mode of operation wherein said seal (<NUM>) does not seal against said fluid passage (<NUM>, <NUM>), said pressure responsive closing mechanism (<NUM>) seals against said inlet port (<NUM>), and said gas operated valve (<NUM>) does not seal against said outlet aperture (<NUM>), so that gas entering said inlet port (<NUM>) of the valve <NUM> can rise and flow past said seal (<NUM>) through said fluid passage (<NUM>, <NUM>), and flow out said outlet aperture (<NUM>), and
comprising another mode of operation wherein said pressure responsive closing mechanism (<NUM>) seals said inlet port (<NUM>), and as soon as fluid cannot flow anymore to said liquid outlet port (<NUM>), said seal (<NUM>) immediately drops to open said fluid passage (<NUM>, <NUM>).