Fluid handling – Self-proportioning or correlating systems – Self-proportioning flow systems
Reexamination Certificate
1999-11-08
2001-12-04
Hepperle, Stephen M. (Department: 3753)
Fluid handling
Self-proportioning or correlating systems
Self-proportioning flow systems
C137S625410
Reexamination Certificate
active
06325089
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a single handle mixing valve for tub spouts and shower heads and more particularly to pressure balanced, volume and temperature controlled mixing valves.
BACKGROUND OF THE INVENTION
Consumer demand has been responsible for the single handle mixing valve for tub and shower installations becoming common in the marketplace. With the passage of time, the single handle mixing valve has undergone design changes to permit large volumetric flows of water through the valve (especially in hotel and other commercial establishments such as gymnasiums, apartments and condominiums) with the end result being that some form of pressure balancing between the hot and cold water supplies feeding the mixing valves has become essential. Without the incorporation of a suitable pressure balancing mechanism in the mixing valves, the operation of such high pressure, high flow volume valves in hotels and gymnasiums could lead to serious injury to the user in the event of a sudden pressure change in the hot or cold water supply to the mixing valve.
Most governing codes require that any tub or shower mixing valve include some kind of a pressure balancing mechanism which is capable of responding to abrupt changes in pressure of the hot and cold water supplies within a very short time to restore the balance of the output flows of hot and cold water to the same proportion as they were before the pressure fluctuation occurred.
Because such mixing valves must fit into a confined space, compromises must be made between performance of the valve and the space required for valve in the plumbing installation. Most prior art valves use a spool type poppet valve mechanism to provide a pressure balance in the hot and cold water supplies feeding the valve. Some of the prior art pressure balancing mechanisms are sufficiently complex as to require the services of sophisticated service personnel to overhaul, dismantle or repair such prior art valves.
It will be immediately apparent that a single handle mixing cartridge valve of a compact size which is capable of controlling large flows of hot and cold water in an inverse manner according to pressure fluctuations in the inlet supplies is a most desirable item for the plumbing industry. If the above valve could comprise a housing containing a single cartridge that was easily removed for repair or replacement by untrained service personnel, the valve is all the more desirable.
SUMMARY OF THE INVENTION
This invention is directed to a single handle pressure balancing mixing valve which has a rotatable cartridge incorporating a pressure balancing mechanism within its casing. The cartridge is attached to an actuating stem to which a handle is attached. The cartridge is accessible and removable from the stem end of the valve mechanism by the simple removal of a single C spring wire clip.
In contrast to prior art balancing mechanisms which typically utilize some type of spool type poppet mechanisms to provide the necessary inverse pressure balancing operation, the balancing mechanism of this invention utilizes a sliding sleeve type device, actuated by a surrounding diaphragm to provide the balancing operation.
By providing a rotatable cartridge in the valve of this invention, both the ingress and egress of water to and from the mixing valve may be suitably controlled.
The use of a diaphragm, in association with the sleeve type balancing mechanism slidably mounted on a stationary tube in the rotatable cartridge, assures a smooth immediate response to small fluctuations in supply pressure during operation of the valve. At the same time, the presence of the diaphragm on the balancing mechanism of this pressure balancing valve makes that mechanism less prone to “sticking” due to the accumulation of scale and sludge on the balancing sleeve or on the stationary tube on which the balance sleeve slides than the prior art poppet valve mechanisms. Prior art poppet type spool mechanisms have a tendency to be objectionably noisy when operating in high pressure feed water situations and alternatively the prior art mechanisms have a tendency to “stick” in low pressure feedwater situations partially because of the many O rings used on the spool shuttle which are required to seal the various pressure chambers. The presence of foreign material carried in the water supply and the scale buildup deposited on valve parts by minerals contained in the water tend to build upon the prior art shuttle mechanism over the working life of the valve tend to amplify the “sticking” problem.
This valve tends to minimize the above problem by the installation of screens within the valve structure which remove foreign material before it may cause malfunction in the valve operation.
The valve of this invention effectively isolates the pressure balancing chamber from the feed water supply when the valve is in the “off” position. Turning the valve “on” precharges the various water passages in the cartridge before any water is allowed to flow through the pressure balancing chambers of the valve.
Another aspect of this invention is the inclusion of an adjustable stop mechanism to adjust and limit the rotational travel of the rotatable cartridge so that the flow of the hot water leaving the hot water port (before entering the mixing chamber of the valve) may be restricted to a preset flow rate by adjusting the position of the hot water stop of the valve. This adjustment maybe conveniently carried out from a point outside the valve housing even after the valve is permanently installed and water is flowing in the valve.
It is an object of this invention to provide a single handle pressure balancing mixing valve wherein the pressure balancing mechanism is more sensitive to fluctuations in input water pressure than prior art valves. The pressure balancing mechanism of applicant's valve continues to function even in the presence of lower inlet water pressure on both hot and cold water supplies than the prior art poppet type spool valves.
It is an object of this invention to supply a single handle pressure balancing mixing valve which utilizes comparatively large water passageways and is essentially silent in operation and not prone to producing water hammer.
It is an object of this invention to provide a single handle pressure balancing valve which may be swiftly dismantled and rebuilt without the removal of screws or other complicated fastening devices requiring special tools and skills.
It is a further object of this invention to provide a pressure balancing assembly which will be relatively insensitive to physical orientation. Thus while other prior art valves specify that the valve must be mounted in a physical orientation where the pressure balancing device (piston in a sleeve) must be horizontal, this valve will function acceptably well in any orientation.
Because of this valve's construction, there is no cross-connecting flow possible between the hot and cold inlet ports when the valve is in the off position. Most prior art valves require check-valves at each inlet ports to prevent cross flow between these ports.
It is a further object of this invention to provide a single handle control pressure balancing valve which simultaneously controls both the ingress and egress of water into and out of the valve. Because of this feature, the user is provided with a single control valve having excellent water temperature and volume selectivity whilst retaining all the benefits of a superior pressure balancing operation.
The main water seal for the cartridge of the pressure balancing valve surrounds the cartridge and is an integral part of the cartridge.
Because the cartridge is rotated by the user during use of this valve, the main water seal sweeps past the inlet water ports during the water temperature selection process, exposing different areas of the main water seal to the hot and cold water inlet port streams; it is well known to those skilled in the art that the water seals in prior art valves tend to perish due to the constant impingement of the hot water i
Breda Silvano
Hepperle Stephen M.
Hughes Ivor M.
Hughes Neil H.
Sarkis Marcelo K.
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