Combination check valve, shutoff and seal for thermostatic valve

A combination check valve, shutoff and seal cartridge is provided for a thermostatic valve, wherein the thermostatic valve includes hot and cold water inlets communicating with an ON/OFF/volume control and/or diverting water valve. The water output of the water volume control is then plumbed to a tub spout, faucet, showerhead or other plumbing device(s). The thermostatic valve has a body with both the cold water inlet and the hot water inlet, and a mixed temperature water outlet for mixed water of a predetermined temperature. Each inlet has respective ports accepting a corresponding combination check valve shutoff and seal cartridge. The cartridge has a housing with a spring therein. The cartridge housing has a seat element, and a pair of elastomeric stop seals fitted in respective sides of the cartridge housing. The seals seal a fluid flow path to the inner sides of the ports of the thermostatic valve body at the hot and cold water inlets of the thermostatic valve body. In an open position water pressure overcomes the spring force of the spring, pushing the seat element away from a respective seal a predetermined distance to permit entry of cold or hot water therein. In a closed shutoff valve mode, the cartridge housing is rotatable 180 degrees, wherein water inlet pressure creates a force in the same direction as the spring which forces the seat element against the seal, to prevent the flow of hot or cold water therethrough.

FIELD OF THE INVENTION 
The field of this invention is mixing values, such as, for example, 
thermostatic valves as used in plumbing. 
BACKGROUND OF THE INVENTION 
Thermostatic valves are used to automatically mix a cold water source and a 
hot water source to provide an output stream of the desired temperature. 
As the on/off and volume adjustments are downstream from the thermostatic 
valve, there are situations where there exists the possibility of 
feedthrough of hot water supply into the cold water source or vice versa. 
Check valves are used in the two water supply inlets to insure that such 
inadvertent mixing is not possible. Also, as a convenience, shutoff valves 
are used at the supply ports as part of the thermostatic valve. These are 
used when servicing the thermostatic valve itself or any system components 
downstream of it. The prior art devices have used separate check valves 
and shutoff valves along with the appropriate seals to incorporate these 
elements into a thermostatic valve housing. 
OBJECT OF THE INVENTION 
It is an object of the present invention to combine check valve, shutoff 
and seal features to increase efficiency by combining the functions of 
valve elements and by reducing the size of the combination check valve, 
shutoff and seals. The resulting cartridge is replaceable, repairable, and 
low cost. 
SUMMARY OF THE INVENTION 
In keeping with the aforesaid objects, the present invention includes a 
combination check valve, shutoff and seal cartridge for a mixing value, 
such as a thermostatic valve, wherein the thermostatic valve includes hot 
and cold water inlets communicating with an ON/OFF and volume control 
water valve. The water output of the water volume control is then plumbed 
to a tub spout, faucet and/or showerhead. 
The thermostatic valve has a body with the cold water inlet and the hot 
water inlet, integral therein, and a mixed temperature water outlet for 
mixed water of a predetermined temperature. Each inlet is an engaging 
means, such as a threaded inlet, a sweat inlet or other appropriate 
engaging members, and each inlet has respective ports accepting a 
corresponding combination check valve shutoff and seal cartridges therein. 
Each cartridge has a housing with a tension member, such as a spring, 
therein. Other tension members, such as a diaphragm, could be utilized as 
well. To prevent leakage, the cartridge housing has a pair of elastomeric 
O-rings in grooves therein. The cartridge housing has a check seat 
element, and a pair of elastomeric stop seals fitted in respective sides 
of the cartridge housing. 
The seals seal a fluid flow path to respective inner sides of the ports of 
the thermostatic valve body at the respective hot and cold water inlets of 
the thermostatic valve body. 
The seals also function both as check valves and shutoff valves of the 
cartridge housing. In an open position water pressure overcomes the spring 
force of the spring, pushing the seat element away from a respective seal 
a predetermined distance to permit entry of cold water therein. 
Furthermore, the cartridge housing is rotatable 180 degrees in either 
direction to shut off the flow of water therethrough. 
In a closed shutoff valve mode, the cartridge housing is rotatable, such 
as, for example, 180 degrees, wherein water inlet pressure creates a force 
in the same direction as the spring which forces the check seat element 
against the seal, to prevent the flow of hot or cold water therethrough.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1A, 1B, 1C and 1D show typical tub, shower or other plumbing 
installations incorporating a mixing valve, such as thermostatic valves 
100, 100a or 100b. Thermostatic valves 100, 100a or 100b accept hot and 
cold water inlets. Water is plumbed to ON/OFF and volume controls 200, 
200a, 200b or 200c. The water output of the latter ON/OFF and volume 
controls 200, 201, 202 or 200c is then plumbed to showerhead 300, as in 
FIG. 1A, hand held spray faucet 300a, as in FIG. 1B, or to either 
showerhead 300b or tub spout 300c, as in FIGS. 1C and 1D. 
FIG. 2 is an exploded view of the components that make up a mixing valve, 
such as thermostatic valve body 100. Thermostatic valve body 100 has a 
cold water inlet 102 and a hot water inlet 103. The outlet for mixed water 
of the proper temperature is 104 or 104a. Engaging ports, such as threaded 
ports 105 and 106, accept the combination check valve, seal and shutoff 
cartridges 101 of this invention. Other engaging ports, such as sweat 
inlets, may also be used. Other means of securing cartridges 101, like 
retaining rings, clips or pins (not shown) may be employed as well. 
As shown in FIGS. 2, 5 and 6, cartridges 101 include a subassembly of 
several components made of a variety of materials, such as, for example, 
rigid molded plastic parts, elastomeric seals, and metal parts, such as 
spring 16, washer 15 and threaded collar 12. 
Cartridge check valve stop housing 11, preferably made of molded plastic, 
has two elastomeric O-rings 13 in grooves on opposite sides of housing 11. 
Movable seat element 17 is preferably a molded plastic part that plays an 
integral role in both the check valve and shutoff valve functions. Two 
elastomeric stop seals 14 fit in the sides of housing 11 and seal the 
fluid flow path to the inner sides of either recess 105 or 106 at the 
water inlets of valve body 100. These same seals 14 function both in the 
check valve or shutoff valve mode of combination valve cartridge 101. 
FIG. 2 also shows conventional parts of thermostatic valve 100, namely, top 
cap 34, trim handle 35, handle base 22 with washer 28, and handle screw 
23, wherein handle base 22 is above plate gasket 10 with O-ring 30. 
Thermostatic valve 100 also has face plate 18 covering spline adapter 6, 
dial 7 in sleeve 9, and O-ring 21 in dial insert 8. Also in sleeve 9 are 
two limit stops 5 within stop ring 4 and cartridge locket nut 3, which is 
placed over standard heat sensitive thermo cartridge 2, which is inserted 
within valve body 100. 
FIG. 3 shows an isometric view of thermostatic valve 100 with cross section 
plane A--A indicated. 
FIG. 4 is a cross sectional view taken at line A--A, showing the position 
of combination check valve seal shutoff cartridges 101 adjacent to cold 
water inlet 102 and hot water inlet 103. 
FIG. 5 is a close up cross sectional detail view showing a combination 
check/seal/shutoff valve cartridge 101 in recess 105 in the open position, 
with water pressure overcoming the spring force of seal spring 16, pushing 
seat element 17 away from seal 14 a distance "d", as noted in area 110, to 
permit entry of cold water. This is the check valve function of 
combination check/seal/shutoff valve cartridge 101. By using the 
screwdriver slot at the top of housing 11 to turn the housing 11 180 
degrees in either direction, the flow of water can be shut off. 
FIG. 6 is a close up cross sectional detail view of combination check valve 
seal shutoff cartridge 101 in the closed shutoff valve mode. Cartridge 101 
is placed in recess 106 adjacent to hot water inlet 103. In FIG. 6, 
housing 11 has been rotated such that inlet water pressure, indicated by 
arrow "WP", now creates a force in the same direction as the force of 
spring 16, thus forcing seat element 17 against seal 14, preventing the 
flow of hot water from inlet 103. 
In another embodiment cartridge 101 may be used with a fluid source, such 
as a hot or cold water source, or other source of fluid therethrough. The 
fluid source includes at least one fluid inlet communicating with a fluid 
flow control, wherein the fluid output, such as hot or cold water or open 
fluid of the fluid flow control is plumbed to at least one fluid output, 
such as a drinking water fountain or a heated water output for hot 
beverages. The fluid source has a body with at least one fluid inlet 
together with the at least one fluid output, which has at least one port 
accepting cartridge 101 therein. 
Cartridge 101 has a tension member and a movable seat element responsive to 
force of said tension member. In a closed position the seat element moves 
away from the seal within the body, wherein in the open position fluid 
pressure overcomes force of the tension member, pushing the seat element 
away from the seal a predetermined distance to permit entry of fluid 
therein. 
Alternatively, cartridge 101 may be rotatable in either direction to shut 
off the flow of fluid therethrough, wherein in a closed shutoff mode the 
housing is rotatable, wherein inlet fluid pressure from an opposite 
direction creates a force in the same direction as the force of the 
tension member, thus forcing the seat element against the seal, preventing 
flow of fluid therethrough. 
It is further noted that other modifications may be made to the present 
invention without departing from the scope of the invention, as noted in 
the appended claims.