Dispensing valve with back flow protection

1. A dispensing valve assembly with back flow protection, said dispensing valve assembly comprising:

a housing having a plurality of inlet passageways connectable at a respective upstream end to a respective supply source;

each of said inlet passageways being in communication with a pressure responsive valve element;

said valve element being yieldably biased to a closed position abutting a discharge valve seat communicating with an outlet passage, with said valve element being moveable to an open position when pressure in said respective inlet passageway exceeds a predetermined value;

each outlet passage being in fluid communication with a common dispensing outlet; and

each outlet passage having a respective flush inlet connected thereto for connection to a flushing air pressure supply that simultaneously flushes all of such said outlets from a downstream side of said respective valve elements through said common dispensing outlet.

2. A dispensing valve assembly as defined in claim 1 further comprising:

said plurality of inlet passageways being circumferentially spaced about said common dispensing outlet and radially extending outwardly therefrom; and

the distances from said common dispensing outlet to said respective upstream ends of said outlet passages being approximately equal.

3. A dispensing valve assembly as defined in claim 2 further comprising:

said valve element comprising a diaphragm; and

said inlet passageways terminating at and in fluid communication with a pressure chamber that seats said diaphragm, said pressure chamber also receiving said discharge valve seat.

4. A dispensing valve assembly as defined in claim 3 further comprising:

said housing constructed such that the common dispensing outlet is at an axial end of said housing and said inlet passageways are disposed circumferentially about said housing transverse to said common dispensing outlet; and

said diaphragm having its outer periphery mounted between two seating shoulders of said housing.

5. A dispensing valve assembly as defined in claim 1 further comprising:

said valve element comprising a diaphragm; and

said inlet passageways terminating at and in fluid communication with a pressure chamber that seats said diaphragm, said pressure chamber also receiving said discharge valve seat.

6. A dispensing valve assembly with back flow protection, said dispensing valve assembly comprising:

a housing having a plurality of inlet passageways connectable at a respective upstream end to a respective supply source;

each of said inlet passageways being in communication with a pressure responsive valve element;

said valve element being yieldably biased to a closed position abutting a discharge valve seat communicating with an outlet passage, with said valve element being moveable to an open position when pressure in said respective inlet passageway exceeds a predetermined value;

each outlet passage being in fluid communication with a common dispensing outlet;

said housing constructed such that the dispensing outlet is at an axial end of said housing and said inlet passageways are disposed circumferentially about said housing transverse to said dispensing outlet;

said valve elements each being a diaphragm seated in a respective pressure chamber at a downstream end of each inlet passageway; and

pairs of said chambers circumferentially spaced about in said housing with each pressure chamber in a respective pair being axially spaced from each other with a pair of passageways interposed between each of said pairs of axially spaced pressure chambers.

7. A dispensing valve as defined in claim 6 further comprising:

said diaphragm having its outer periphery mounted between two seating shoulders of said housing.

8. A dispensing valve assembly with back flow prevention, said dispensing valve assembly comprising:

a housing having a common dispensing outlet;

a plurality of diaphragm backflow prevention valves carried by said housing and each having a discharge outlet in fluid communication with said common dispensing outlet and an inlet in communication with separate supply ports; and

each discharge outlet having at its upstream end a flush inlet for connection to a pressurized fluid supply for flushing each discharge outlet and said common dispensing outlet when said plurality of diaphragm backflow prevention valves are in a closed position.

9. A dispensing valve assembly as defined in claim 8 further comprising:

said housing including a manifold plate;

a spring cup retainer plate on each axial side of said manifold plate and having a first side abutting said manifold plate;

a cap plate abutting a second side of each spring cup retainer plate;

said common dispensing passage axially extending through said plates;

said spring cup retainer plate housing a plurality of springs and spring cups;

each diaphragm back flow prevention valve including one of said spring cups abutting against a respective diaphragm with said respective spring biasing said one spring cup and diaphragm to a closed position against a discharge outlet seat;

each respective diaphragm being sealably seated about its periphery between said spring cup retainer plate and said manifold plate;

said manifold plate having a respective inlet passage in continuous communication with said diaphragm about said discharge outlet seat; and

said common dispensing passage in selective fluid communication with a said respective inlet passage when said diaphragm is in an open position with respect to said discharge outlet seat.

10. A dispensing valve assembly as defined in claim 9 further comprising:

said common dispensing outlet passage being at a radial center of said housing;

said diaphragm back flow prevention valves being circumferentially spaced about said common dispensing outlet passage and being equidistant from said common dispensing outlet passage; and

said inlet passages being all at the same axial level on said manifold plate.

11. A dispensing valve assembly as defined in claim 2 further comprising:

said outlet passages being circumferentially spaced about said common dispensing outlet and radially extending outward therefrom; and

said respective flush inlet being connected at a radially outer end of a respective outlet passage.

12. A dispensing valve assembly with back flow prevention, said dispensing valve assembly comprising:

a housing having a common dispensing outlet;

a plurality of diaphragm backflow prevention valves carried by said housing and each having a discharge outlet in fluid communication with said common dispensing outlet and an inlet in communication with separate supply ports;

said housing including a manifold plate;

a spring cup retainer plate on each axial side of said manifold plate and having a first side abut said manifold plate;

a cap plate abutting a second side of each spring cup retainer plate;

said common dispensing passage axially extending through said plates;

said spring cup retainer plate housing a plurality of springs and spring cups;

each diaphragm back flow prevention valve including one of said spring cups abutting against a respective diaphragm with said respective spring biasing said one spring cup and diaphragm to a closed position against a discharge outlet seat;

each respective diaphragm being sealably seated about its periphery between said spring cup retainer plate and said manifold plate;

said manifold plate having a respective inlet passage in continuous communication with said diaphragm about said discharge outlet seat; and

said common dispensing passage in selective fluid communication with a said respective inlet passage when said diaphragm is in an open position with respect to said discharge outlet seat.

13. A dispensing valve assembly as defined in claim 12 further comprising:

said common dispensing outlet passage being at a radial center of said housing;

said diaphragm back flow prevention valves being circumferentially spaced about said common dispensing outlet passage and being equidistant from said common dispensing outlet passage; and

said inlet passages being all at the same axial level on said manifold plate.