Bi-stable changeover valve
A valve comprises a body having a first inlet, a second inlet, and an outlet. A shuttle is shiftable between: a first position permitting communication between the first inlet and the outlet and blocking communication between the second inlet and the outlet; and a second position permitting communication between the second inlet and the outlet and blocking communication between the first inlet and the outlet. One or more permanent magnets are positioned to bias the shuttle away from a neutral position between the first position and the second position, wherein the valve further comprises: one or more electromagnets positioned to, in at least one condition of energization, counter said bias.
1. A valve for dispensing foodstuff, comprising:
a body having a first inlet, a second inlet, a valve outlet, and internal foodstuff passageways, the body formed of a food-grade material, the internal foodstuff passageways configured to permit communication between the inlets and the valve outlet;
a shuttle shiftable between:
a first position permitting communication between the first inlet and the valve outlet and blocking communication between the second inlet and the valve outlet; and
a second position permitting communication between the second inlet and the valve outlet and blocking communication between the first inlet and the valve outlet; and
one or more permanent magnets positioned to bias the shuttle away from a neutral position between the first position and the second position; and,
one or more electromagnets positioned to, in at least one condition of energization, counter said bias.
2. The valve of claim 1 wherein:
a shift of the shuttle between the first position and the second position comprises a linear shift.
3. The valve of claim 1 wherein:
the one or more permanent magnets comprise a first permanent magnet biasing the shuttle toward the first position and a second permanent magnet biasing the shuttle toward the second position.
4. The valve of claim 3 wherein:
the first permanent magnet is a ring and the second permanent magnet is a ring.
5. The valve of claim 1 wherein:
the one or more electromagnets comprise a first electromagnet and a second electromagnet.
6. The valve of claim 1 further comprising:
at least one position sensor positioned to detect the position of the shuttle.
7. A food or beverage dispensing apparatus comprising:
the valve of claim 1 ;
a dispensing outlet;
a pump between the valve outlet and the dispensing outlet;
a first fitting for coupling a first pouch to the first inlet; and
a second fitting for coupling a second pouch to the second inlet.
8. The apparatus of claim 7 further comprising a controller having programming to:
receive identifying information for said first pouch and said second pouch; and
responsive to the identifying information, energize the at least one electromagnet so as to maintain a net bias on the shuttle different from the bias applied by the one or more permanent magnets.
9. The apparatus of claim 8 wherein the net bias allows the sequential dispensing from the first pouch and the second pouch with a pressure drop associated with an emptying of one of the first pouch and second pouch shifts the shuttle to dispense from the other of the first pouch and second pouch.
10. The apparatus of claim 9 wherein the net bias accommodates a viscosity of material in the first pouch and the second pouch.
11. The apparatus of claim 7 further comprising a refrigeration system.
12. The apparatus of claim 7 being a beverage dispensing apparatus and further comprising:
a water inlet connectable to a water source and coupled to a flowpath between the valve and the dispensing outlet.
13. The apparatus of claim 7 being a condiment dispensing apparatus wherein the dispensing outlet is along a spout.
14. A method for using the apparatus of claim 7 , the method comprising:
energizing the at least one electromagnet so as to maintain a net bias on the shuttle different from the bias applied by the one or more permanent magnets.
15. The method of claim 14 wherein:
the method is repeated to dispense a plurality of different foodstuffs and wherein the net bias compensates for a viscosity or solids content of the different foodstuffs.
16. The apparatus of claim 7 wherein the valve further comprises:
at least one position sensor positioned to detect the position of the shuttle.
17. The apparatus of claim 7 further comprising:
said first pouch and said second pouch, the first fitting coupling the first pouch to the first inlet, the second fitting coupling the second pouch to the second inlet.
18. A method for using the valve of claim 1 , the method comprising:
energizing the at least one electromagnet so as to overcome the bias and shift the shuttle from one of the first position and the second position to the other.
19. The method of claim 18 further comprising:
energizing the at least one electromagnet so as to resist the bias and allow a pressure difference to shift the shuttle from one of the first position and the second position to the other.
20. The method of claim 18 further comprising:
energizing the at least one electromagnet so as to supplement the bias.