Pressure balancing spool mixing valve
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There is herein described a single handle pressure balancing spool valve for mixing user-adjustable hot and cold water flow to a fixture such as a shower or tub and to adjust the rate of mixed water flow. A rotatable disc with hot and cold intake openings and an outlet opening are provided which control the degree of covering on the inlet ports of the valve. Pressure balancing of inlet pressure is provided within the valve by means of a piston-cylinder assembly to compensate for fluctuations in water inlet pressure to avoid scalding of the user.

Martin, Robert (Myrtle Beach, SC, US)
Li, Danny (Norcross, GA, US)
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Wolverine Brass, Inc.
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Primary Examiner:
Attorney, Agent or Firm:
We claim:

1. A single control pressure balancing spool mixing valve comprising: an upper single control cartridge and a lower pressure control housing, said cartridge and housing being joined together axially; said control cartridge including an operating spindle extending axially therein and being rotatable about its longitudinal axis; a pivot pin extending through said spindle intermediate the ends of the spindle, whereby said spindle can pivot about said pin; said pressure control housing having a hot water inlet, a cold water inlet, and a mixed water outlet; moveable disc means adopted to proportion the amount of hot and cold water flowing through the valve to said mixed water outlet, said means being operatively connected to one end of said spindle for rotation therewith; said moveable disc having a recess on one surface thereof to receive said one end of said spindle, whereby movement of said spindle about said pin will cause lateral movement of said moveable disc; means on said moveable disc to control the volume of mixed water flow as a result of the pivoting of the spindle and the moveable disc; pressure balance means within said housing and in communicate with both the hot and cold water inlets to sense and compensate for any fluctuation in the pressure of either the hot or cold water.

2. The valve as defined in claim 1, wherein said pressure balance means comprises a pair of oppositely facing side housings, each having a generally cylindrical recess, a cylinder received within said recesses, and a piston slidable within said cylinder, one of said side housings being in fluid communication with inflowing hot water and the other being in communication with inflowing cold water.

3. The valve as defined in claim 2, wherein the cylinder and the piston are formed on stainless steel.

4. The valve as defined in claim 1, and further including an operating handle secured to the other end of said spindle for rotating and pivoting the same to control the temperature and flow rate of water to said outlet.

5. The valve as defined in claim 1, wherein said moveable disc means is rotatable upon rotation of said spindle.

6. The valve as defined in claim 5, and further including a keyhole-shaped recess on its lower face, and a fixed disc having openings in communication with the hot and cold water inlets and said outlet, said moveable disc upon rotation with respect to said fixed disc varies the proportional amount of hot and cold water flowing to said outlet.

7. The valve as defined in claim 5, wherein said openings in said fixed disc for the hot and cold water are arcuate in shape.

8. The valve as defined in claim 7, wherein said opening in said fixed disc for the mixed water outlet is generally circular in shape.



The present invention relates to a cartridge type of pressure-balancing spool valve for use in residential and commercial plumbing applications, particularly for bathtubs and showers. More particularly mixing valves of this type are employed for balancing water pressure, volume of flow and water temperature.


In the plumbing market today, single handle mixing valves are common, especially for use in sinks, tubs and shower installations. Many of these valves will mix the flow of hot and cold water to suit the desires of the user. The more expensive and advanced valves of this type also include a pressure balancing assembly to prevent a rapid change of water temperature when either the hot water supply or cold water supply pressure drops. This can cause severe injury due to scalding if not corrected.

Such pressure drops can occur if another plumbing apparatus, such as a dishwasher, faucet, toilet or washing machine is actuated, which can result in an excessive flow of either hot or cold water. Many types of pressure balancing components have been incorporated in mixing vales in order to obviate such problems.

There is a need in the art for a cartridge type mixing valve which provides pressure balancing between the hot and cold water supplies and which also provides a full adjustment of the water temperature from full cold to about 115° F. in a compact easily assembled mixing valve housing which has provision for easy replacement of parts when needed.


In accordance with a preferred embodiment of our invention, a pressure balancing mixing valve is provided which incorporates a plastic three-piece pressure balancing spool housing component which is adapted to be attached to and integrated with a standard 35 mm ceramic disc single control valve cartridge.

It is a primary object of our invention to provide a pressure balanced mixing valve which includes a group of components, each having individual functions, which are pre-assembled and integrated to form a valve assembly which can be easily inserted and removed as a unit from the body of a tap.

This object is achieved by superimposing and assembling the ceramic disc mixer valve and pressure balancer or regulator as a single unit for correct positioning within the plumbing fixture or tap.

It is a further object of the invention to provide a novel pressure balance cartridge valve assembly that can be easily removed from a plumbing system for replacement or repair of component parts.

Another object of the invention is to provide a pressure balancing valve assembly that is relatively inexpensive to manufacture and which is durable and reliable in use and which is designed to prevent injury due to scalding of the user due to fluctuations in water pressure in the plumbing system.

Further objects of the invention will become apparent upon a careful reading of the appended specification, claims and drawings, wherein like reference characters refer to the same elements which appear in the several views.


It has been previously suggested in the prior art to incorporate pressure balancing and mixing of hot and cold water in a single control valve. An example of such a valve is shown in Otelli, U.S. Pat. No. 6,732,754.

Another example of a pressure balancing mixing-valve is shown in Marty et al., U.S. Pat. No. 5,35,906

Lin et al., U.S. Pat. No. 6,176,250, is directed to a pressure balance sub-assembly for proportionally mixing hot and cold water.

In these known constructions, the pressure balance valve portion has been subject to erratic operation, breakage and fouling, all of which have been obviated in our new valve construction.

In addition to the above, the assemblage of the main components of the prior art valves has been complicated and time-consuming resulting in additional manufacturing costs.


Consistent and consonant with the present invention, a pressure balancing spool mixing valve is disclosed which incorporates a generally conventional 35 mm ceramic disc single control cartridge with a three piece pressure balance housing design which attaches to the disc cartridge assembly.


These and other objects of our invention will be appreciated and understood by those skilled in the art from the detailed description of the preferred embodiment of the invention and from the following drawings in which:

FIG. 1 is a bottom right perspective view of a pressure balancing spool pressure valve constructed according to our invention;

FIG. 2 is a top right perspective view opposite of the view in FIG. 1;

FIG. 3 is a cross-sectional view of the top operating portion of the valve showing a typical installation with an operating handle in a bath or shower environment;

FIG. 4 is an exploded perspective of the major operating components of the valve including the pressure balancing cylinder and piston and the two side housings;

FIG. 5 is an exploded perspective showing the assembly of the fixed and movable discs for control of hot and cold water flow;

FIG. 6 is a cross-section of the entire valve assembly taken from the left side along line 6-6 of FIG. 1 and showing the valve in the fully closed position wherein no flow to the outlet takes place;

FIG. 7 is a cross-section taken along line 7-7 of FIG. 6 showing the inlets and outlet in the disc assembly when the valve is closed;

FIG. 8 is a cross-section of the entire valve assembly similar to FIG. 6 showing the valve in the fully open position wherein both hot and cold water may flow to the valve outlet.

FIG. 9 is a cross-section taken along Line 9-9 of FIG. 8 showing the inlets and outlet in the disc assembly when the valve is open.

FIG. 10 is a cross-section similar to FIG. 9 and showing the valve in the position for maximum hot water flow.

FIG. 11 is a cross-section similar to FIG. 9, but showing the valve in the position for maximum cold water flow.

FIG. 12 is a cross-section of the valve in FIG. 6 taken along the line 12-12 thereof.


With reference to the drawings wherein like reference characters designate like or corresponding elements throughout the several views, it will be seen that the invention relates to a pressure balancing spool mixing valve shown generally at 10. The body of the valve itself is preferably formed from any well known plastic material.

In the preferred embodiment, the valve 10 is an assembly of two major components, a pressure balancing sub-assembly 11 and a conventional ceramic disc single control cartridge sub-assembly 12, which is preferably of a standard 35 mm outside diameter in order to fit within existing home and commercial plumbing fixtures.

The two sub-assemblies 11 and 12 are retained and held together by a tab 13 and slot 14 connection or any other suitable means known to those skilled in the art.

As can be seen in FIG. 3, the cartridge valve assembly extends through an opening in a bathroom wall W, for example. The operating spindle 15 of the valve is connected to a conventional shower handle 16 by means of a screw 17 or other fastener which is received in a threaded bore 18 in the end of the spindle 15. A trim plate or escutcheon T conceals and covers the assembly.

Spindle 15 is secured by means of a metal pin 19 to a rotatable plastic disc 20, whereby rotation of the handle 16 will result in the rotation of the spindle 15 about its longitudinal axis, resulting in rotation of the disc 20 for the purpose of control of water temperature at the outlet of the valve. The spindle can also be pivoted about the pin 19 in order to control the rate of flow or pressure of the water at the valve outlet.

The rotatable disc 20 and the operating spindle are received within the plastic cartridge housing 21 as noted in FIG. 4 of the drawings. A plastic locating ring 22 is fixed over the rotatable disc and attaches to the top of the housing 21.

The end of the operating spindle 15 internal of the valve assembly is provided with a finger or foot 23 engageable within a recess 24 in ceramic plate or holder 25. This plate has depending lugs 26 which are engageable with recesses 27 formed in moveable disc 28. Formed into the bottom surface of disc 28 is a keyhole recess or depression 29 which controls the outflow of water through the valve as described further herein.

Pivotal movement of spindle 15 about the pin 19 serves to move ceramic plate 25 and the disc 28 to which it is attached and which includes the keyhole recess 29.

The bottom portion of our new valve constituting the pressure balancing assembly 11 includes a plastic molded housing 30. Three openings are formed in the bottom of the housing; the hot water inlet 31, the cold water inlet 32, and the mixed water outlet 33. Silicon gaskets 34 surround the hot and cold water inlets. An o-ring gasket 35 extends about the periphery of housing 30 as is conventional in the art.

The top or upper surface of the molded housing 30 is provided with three preferably circular water openings 36 to correspond with the hot and cold water inlets and the outlet. O-ring gaskets 37 are fitted about these openings

A plurality of upstanding lugs 38 extend from the housing 30 and receive a fixed disc 39 by virtue of interengagement with complementary recesses 38a and which disc is provided with a pair of arcuate openings 40 and 41 and a larger generally circular opening 42.

It may be seen from an inspection of FIGS. 4, 5, 7, 9, 10 and 11 that rotation of the shower handle 16 and its connected operating spindle 15 will result in the rotation of the moveable disc 28 with respect to the fixed disc 39. Such rotation opens and closes the passageways for the hot and cold water which communicate with the keyhole recess 29 for the purpose of mixing the appropriate proportion of hot and cold water to the outlet 33.

Pressure balancing of the water is accomplished by the inclusion in the plastic housing 21 of pressure balance sub-assembly shown at the bottom of FIG. 4. This includes a pair of oppositely directed side housings 43 and 44, each having a cylindrical opening 45 to receive a stainless steel cylinder 46 in which freely slides a stainless steel piston 47. The side housings surround and seal the anti-fouling treated stainless steel cylinder and piston.

The stainless steel piston acts to compensate the flow due to water pressure fluctuations while each side housing maintains the hot and cold water supplies separated at all times.

The pressure balancing assembly 11 is snap fitted to the ceramic single control cartridge 12 as shown in FIGS. 1 and 2.

Our invention is not limited to the above-noted embodiment as various modifications can be readily made by those skilled in the art. Such changes in form and detail may be made without a departure from the scope and spirit of our present invention.