GB2033056A

GB2033056A - Water taps

Info

Publication number: GB2033056A
Application number: GB7934595A
Authority: GB
Original assignee: British Aerospace PLC
Current assignee: BAE Systems PLC
Priority date: 1978-10-07
Filing date: 1979-10-05
Publication date: 1980-05-14
Also published as: GB2033056B

Abstract

A water tap, particularly suitable for aircraft cabin use, in which a predetermined flow period is defined by a float valve 11 controlled by a hydraulic dashpot (15, 16, 19) having a valve (20, 21) which allows automatic priming when flow is initiated and automatic draining when the water system to which the tap is connected is drained to prevent freezing. <IMAGE>

Description

SPECIFICATION Water taps This invention relates to water taps of the type which shut off flow after a predetermined period and which accordingly conserve water.

An object of the invention is the provision of a tap in which the predetermined flow period is defined by hydraulic means.

A further object of the invention is the provision of a tap in which the hydraulic means is both self priming when flow is initiated and self draining when the water system with which the tap is associated is drained to prevent freezing.

According to the invention a water tap includes float valve means arranged in use to float to a water shut-off position, plunger means arranged to urge the float valve means to a water supply position and hydraulic dashpot means effective to oppose movement of the float valve means toward the shut-off position, the dash pot means including both metering means and valve means, the valve means being biased toward an open position allowing water to flow freely into and out of the dashpot means but being temporarily closable during movement of the float valve means toward the shut-off position, so that a restricted flow is urged from the dashpot means through the metering means.

By this arrangement, the dash pot means is both self priming and self draining and provides a predetermined flow period before shut-off.

A preferred embodiment of the invention is described with reference to the accompanying drawing which is a vertical cross-sectional about an axis X-X of a tap in an upright operating position. For descriptive purposes, that section to the left of the axis X-X is shown with the tap in a water supply position and that to the right shows the tap in a shutoff position.

The tap includes a housing 1 of internal cylindrical form having, at its base, a water inlet 2, and, to one side, a water delivery outlet 3. The water inlet 2, in use, is connected to a water supply system (not shown) whilst the outlet 3 is connected to a spray or other delivery nozzle, the ducting to which is shown at 4. Located within the housing is a body assembly 5 which is lowerable into the housing from the top; accordingly, it can be readily removed for maintenance without disconnecting the water supply system. The body assembly includes a dividing wall 6 which sealingly engages with the housing to form a float chamber 7 adjacent the inlet 2.

The dividing wall 6 has a bore 8, lying coaxial with the axis X-X, within which is slidably located a stem portion 9 of a float valve member 1 0. The latter has its float portion 11 housed in the chamber 7 and has a frustoconically formed valve face 1 2 formed at the junction of the float and stem portions. This valve face seals against a matching frustoconical seat 1 3 formed on the wall 6 coaxially with the bore 8 when in a flow shut-off position as shown to the right of axis X-X.

The stem portion of the float valve member is hollow and has apertures in its wall, so that water in the float chamber 7 can flow through it when the valve is in a water supply position, as shown to the left of the axis X-X.

Above the wall 6 is formed a further chamber 1 4 with which the outlet 3 communicates and into which the hollow stem portion 9 of the float valve member protrudes.

Above and bounding the chamber 1 4 lies a cylinder 15, being part of the body assembly.

It lies co-axial with the axis X-X and has a closure member 1 6 at its uppermost end, i.e.

that end remote from the wall 6. Through the closure member 1 6 and sealed with respect to it extends a plunger assembly 1 7 which is coaxial with the axis X-X. It extends into the chamber 14 to contact the stem portion 9 of the float valve member when depressed.

Downward axial movement of the plunger assembly 1 7 is effected by an external hand lever 18, sufficient movement being provided to unseat the float valve 10 and move it to the water supply position.

Slidably located, again co-axially, within the cylinder 15 is an annular piston 19. The piston 1 9 is axially movable through a limited distance with respect to the plunger assembly 1 7 to thereby effect opening and closing of a valve formed by a frusto-conical seat 20 on the piston and a complementary frusto-conical valve member 21 formed upon the plunger assembly 1 7. Since it surrounds the plunger assembly, the valve aperture is annular; it allows water to pass from the chamber 14 through the piston 1 9 into the cylinder 1 5.

The piston 1 9 is biased upwards away from the valve member 21 by a coil spring 22 whilst the plunger assembly 1 7 is biased upwards away from the wall 6 by a coil spring 23.

The cylinder 1 5 has a metered communication with the water outlet duct 4 by means of an orifice 24; accordingly, water can be forced by the piston out of the cylinder at a controlled rate giving a correspondingly controlled rate of piston movement. Items 15, 16, 19, 20, 21 and 24 form a dashpot assembly.

Operationally, the tap functions as follows: water is admitted to the chamber 7 through the inlet 2 causing the float valve to rise to the shut-off position and thereby prevent water flow. Downward pressure on the hand lever 1 8 causes the plunger assembly 1 7 to move axially downward against the bias of the spring 23 to contact the stem portion 9 of the float valve; further downward movement unseats the float valve which thus al lows water to pass through the chamber 1 4 and into the outlet 3 for delivery. At this stage, the dashpot valve 20, 21 is open under the bias of the spring 22 thereby admitting water from the chamber 14 into the cylinder 15, thus priming the dashpot.Release of the hand lever 1 8 allows the plunger assembly 1 7 to rise under the combined urging of the float valve and the spring 23, the water pressure in the cylinder causing the piston 1 9 to move relatively to the plunger assembly and close the dashpot valve 20, 21.

Further upward movement of the plunger assembly carries the piston upwards to force the water in the cylinder through the orifice 24 at a predetermined rate, thereby providing an opposing force to float valve closure. Eventually all the water in the cylinder is exhausted whereupon the float valve is allowed to close to shut off supply. Pressures are equalised above and below the piston 19, so that the dashpot valve 20, 21 is allowed to open again under the bias of its spring 22. Accordingly, the dashpot is again ready for priming on depression of the hand lever 18; conversely, should the water system to which the tap is connected be drained, for example, to prevent ice formation, the open dashpot valve 20 allows any residual water in the dashpot to readily drain out.

Claims

1. A water tap including float valve means arranged in use to float to a water shut-off position, plunger means arranged to urge the float valve means to a water supply position, and hydraulic dash pot means effective to oppose movement of the float valve means toward the shut-off position, the dashpot means including both metering means and valve means, the valve means being biased toward an open position allowing water to flow freely into and out of the dashpot means but being temporarily closable during movement of the float valve means toward the shut-off position, so that restricted flow is urged from the dashpot means through the metering means.

2. A water tap according to claim 1 wherein the dashpot valve means is biased toward the open position by spring means but is temporarily closable by water temporarily trapped within the dashpot means.

3. A water tap according to claim 1 or claim 2 wherein the plunger means is actuated by external lever means.

4. A water tap including housing means adapted to be connected to water supply duct means and body means for insertion into and removal from the housing means without necessarily disconnecting the supply duct means, the body means carrying float valve means arranged in use to float to a supply water shut-off position, externally operated plunger means arranged to urge the float valve means to a water supply position, and hydraulic dashpot means effective to oppose movement of the float valve means toward the shut-off position, the dash pot means including both metering means and valve means, the valve means being biased toward an open position allowing water to flow freely into and out of the dashpot means but being temporarily closable during movement of the float valve means toward the shut-off position, so that a restricted flow is urged from the dashpot means through the metering means

5. A water tap according to claim 4 wherein the housing means is of cylindrical internal form and the body means, the float valve means, the plunger means, and the hydraulic dashpot means are coaxially arranged to lie within the cylinder.

6. A water tap substantially as described with reference to the accompanying drawing.