Safety valve for a dairy system component
A system for cleaning a dairy animal milker unit and applying dip to a dairy animal, the system includes a main control, an air supply, a water supply, a backflush fluid supply, a dip supply, a stall control for receiving the air, water, backflush fluid and dip supplies, and a safety valve that is adjacent to a downstream portion of the milker unit to control backflush and dip fluids being fed to the milker unit.
1. A safety valve for a dairy system, the safety valve comprising:
a milk inlet constructed and arranged to receive milk from a milker unit;
a milk outlet constructed and arranged to provide milk received at the milk inlet to a milk tube;
a backflush inlet constructed and arranged to receive backflush fluid; and
a set of controllable seals constructed and arranged selectively to (i) assume a first mode in which milk is allowed to pass from the milk inlet to the milk outlet or (ii) assume a second mode in which backflush fluid is allowed to pass from the backflush inlet to the milk inlet.
2. The safety valve of claim 1 wherein, in the first mode, the set of controllable seals is further constructed and arranged to block a flow of the backflush fluid from the backflush inlet to the milk inlet.
3. The safety valve of claim 1 wherein, in the second mode, the set of controllable seals is further constructed and arranged to block a flow of the milk from the milk inlet to the milk outlet.
4. The safety valve of claim 3 wherein, in the second mode, the set of controllable seals includes a first seal with the milk inlet and second seal with the milk outlet, the first seal and the second seal connected by at least one bleed path configured to equalize differential pressure between the first seal and the second seal.
5. The safety valve of claim 4 , further comprising at least one vent that extends from said at least one bleed path to an environment around the safety valve.
6. The safety valve of claim 4 , wherein said at least one bleed path includes a first bleed path within the safety valve and a second bleed path within the safety valve, the first bleed path being at least partially distinct from the second bleed path.
7. The safety valve of claim 1 , further comprising:
a dip inlet configured to receive teat dip,
wherein the set of controllable seals is further constructed and arranged selectively to pass teat dip from the dip inlet to the milk inlet.
8. The safety valve of claim 1 , wherein the controllable seals are actuated by compressed air.
9. A method of controlling fluid flow in a dairy system, the method comprising:
receiving, by a milk inlet of a safety valve, milk from a milker unit;
providing, by a milk outlet of the safety valve, milk received at the milk inlet to a milk tube;
receiving backflush fluid at a backflush inlet of the safety valve; and
operating a set of controllable seals of the safety valve to (i) assume a first mode in which milk is allowed to pass from the milk inlet to the milk outlet or (ii) assume a second mode in which backflush fluid is allowed to pass from the backflush inlet to the milk inlet.
10. The method of claim 9 , further comprising operating the set of controllable seals in the first mode to block a flow of the backflush fluid from the backflush inlet to the milk inlet.
11. The method of claim 9 , further comprising operating the set of controllable seals in the second mode to block a flow of the milk from the milk inlet to the milk outlet.
12. The method of claim 11 , further comprising, in the second mode:
forming a first seal with the milk inlet;
forming a second seal with the milk outlet; and
providing at least one bleed path between the first seal and the second seal to equalize differential pressure between the first seal and the second seal.
13. The method of claim 12 , further comprising venting said at least one bleed path to an environment around the safety valve.
14. The method of claim 12 , wherein said at least one bleed path includes a first bleed path within the safety valve and a second bleed path within the safety valve, the first bleed path being at least partially distinct from the second bleed path.
15. The method of claim 9 , further comprising:
receiving teat dip at a dip inlet of the safety valve,
wherein operating the set of controllable seals includes, in the second mode, selectively passing teat dip from the dip inlet to the milk inlet.
16. The method of claim 9 , further comprising actuating the set of controllable seals using compressed air.