Safety valve for an automated milker unit backflushing and teat dip applicator system

Abstract

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 selectively conducting at least a first fluid and a second fluid, comprising:
 a first port;   a second port;   a third port; and   a piston,   the piston having a first position in which the first fluid is enabled to pass between the first port and the second port, and a second position in which the second fluid is enabled to pass between the third port and the first port.   
     
     
         2 . The safety valve of  claim 1 , further comprising a spring constructed and arranged to bias the piston toward the first position. 
     
     
         3 . The safety valve of  claim 1 , further comprising a pressurized air supply constructed and arranged to provide pressurized air to force the piston toward the second position. 
     
     
         4 . The safety valve of  claim 1 , further comprising a seal insert constructed and arranged to prevent the second fluid from passing between the third port and the first port when the piston is in the first position and to prevent the first fluid from passing between the first port and the second port when the piston is in the second position. 
     
     
         5 . The safety valve of  claim 1 , further comprising:
 a first seal;   a bleed path; and   a second seal,   wherein, when the piston is in the second position, the first seal and the second seal are spaced apart from each other in a flow path between the third port and the first port and the bleed path is provided from a region between the first seal and the second seal to an environment of the safety valve.   
     
     
         6 . The safety valve of  claim 1 , further comprising:
 a fourth port;   a fifth port; and   a second piston,   the second piston having a first position in which a third fluid is enabled to pass between the fourth port and the fifth port and a second position in which the third fluid is disabled from passing between the fourth port and the fifth port.   
     
     
         7 . The safety valve of  claim 6 , further comprising:
 a third seal;   a bleed path; and   a fourth seal,   wherein, when the second piston is in the second position, the third seal and the fourth seal are spaced apart from each other in a flow path between the fourth port and the fifth port and the bleed path is provided from a region between the third seal and the fourth seal to an environment of the safety valve.   
     
     
         8 . A milking system, comprising:
 a milker unit;   a milk collecting tank;   a backflush supply; and   a safety valve for selectively conducting at least a first fluid and a second fluid, the safety valve including   a first port,   a second port,   a third port, and   a piston,   the piston having a first position in which the first fluid is enabled to pass between the first port and the second port, and a second position in which the second fluid is enabled to pass between the third port and the first port,   wherein the first port is connected to the milker unit, the second port is connected to the milk collecting tank, and the third port is connected to the backflush supply.   
     
     
         9 . The milking system of  claim 8 , further comprising:
 a teat dip supply; and   a teat dip applicator,   wherein the safety valve further includes a fourth port connected to the teat dip supply, a fifth port connected to the teat dip applicator, and a second piston, the second piston having a first position in which a third fluid is enabled to pass between the fourth port and the fifth port, and a second position in which the third fluid is disabled from passing between the fourth port and the fifth port.   
     
     
         10 . A method for selectively conducting at least a first fluid and a second fluid using a safety valve having at least a first port, a second port, and a third port, the method comprising:
 with a piston in a first position, conducting the first fluid between the first port and the second port; and   with the piston in a second position, conducting the second fluid between the third port and the first port.   
     
     
         11 . The method of  claim 10 , further comprising moving the piston to the first position in response to a force provided by a spring. 
     
     
         12 . The method of  claim 10 , further comprising moving the piston to the second position in response to applying compressed air. 
     
     
         13 . The method of  claim 10 , further comprising, with the piston in the first position, preventing the second fluid from passing between the third port and the first port. 
     
     
         14 . The method of  claim 10 , further comprising, with the piston in the second position, preventing the first fluid from passing between the first port and the second port. 
     
     
         15 . The method of  claim 14 , wherein preventing the first fluid from passing between the first port and the second port is carried out by a first seal and a second seal spaced apart from each other, and wherein the method further comprises venting a region within the safety valve between the first seal and the second seal to an environment of the safety valve. 
     
     
         16 . The method of  claim 10 , wherein the safety valve further includes a fourth port and a fifth port, and wherein the method further comprises:
 with a second piston in a first position, enabling a third fluid to pass between the fourth port and the fifth port; and   with the second piston in a second position, disabling the third fluid from passing between the fourth port and the fifth port.   
     
     
         17 . The method of  claim 16 , further comprising:
 receiving, by the fourth port, the third fluid from a teat dip supply; and   providing, by the fifth port, the third fluid to a teat dip applicator.   
     
     
         18 . The method of  claim 16 , wherein disabling the third fluid from passing between the fourth port and the fifth port includes physically blocking the third fluid from passing between the fourth port and the fifth port. 
     
     
         19 . The method of  claim 18 , wherein physically blocking the third fluid from passing between the fourth port and the fifth port is carried out by a third seal and a fourth seal spaced apart from each other within the safety valve, and wherein the method further comprises venting a region between the third seal and the fourth seal to an environment of the safety valve. 
     
     
         20 . The method of  claim 10 , further comprising:
 receiving, by the first port, the first fluid from a milker unit;   providing, by the second port, the first fluid to a milk collecting tank;   receiving, by the third port, the second fluid from a backflush supply; and   providing, by the first port, the second fluid to the milker unit.