Liquid dispenser and method for preventing liquid segregation
An apparatus for selectively dispensing liquids, such as paint colorants. The apparatus comprises container assemblies with a container and a pump. A pump conduit connects the pump to a valve assembly. A recirculation conduit connects the container to the valve assembly bypassing the pump. The valve assembly is configured to be switched between a dispensing position and a recirculation position closing off the dispense conduit. Method of preventing segregation of a multiphase liquid in a pump conduit between a container and a dispense conduit. A valve assembly between the pump conduit and the dispense conduit closes off the dispense conduit while it opens a recirculation conduit between the container and the valve assembly. The liquid is circulated via a circuit formed by the container, the pump conduit, the valve assembly and the recirculation unit.
1. An apparatus for selectively dispensing one or more of a plurality of liquids, the apparatus comprising a plurality of container assemblies, wherein each of the container assemblies comprises:
a container;
a pump operatively connected to the container;
a valve assembly;
a pump conduit connecting the pump to the valve assembly;
a recirculation conduit connecting the container to the valve assembly bypassing the pump; and
a dispense conduit connected to the valve assembly;
wherein each of the valve assemblies of each of the container assemblies is configured to be switched between a dispensing position and a recirculation position by a common actuator thereby closing off the respective dispense conduits;
wherein the common actuator is a driving axle extending through the valve assemblies.
2. The apparatus of claim 1 , wherein each of the pumps is a bidirectional pump.
3. The apparatus of claim 1 , wherein in at least one of the container assemblies the pump is a positive displacement pump.
4. The apparatus of claim 1 , wherein at least some of the valve assemblies comprise a three-way valve.
5. The apparatus of claim 4 , wherein the three way valves are disc valves.
6. The apparatus of claim 4 , wherein at least some of the three way valves are arranged in stacked valve housings.
7. An apparatus for selectively dispensing one or more of a plurality of liquids, the apparatus comprising a plurality of container assemblies, wherein each of the container assemblies comprises:
a container;
a pump operatively connected to the container;
a valve assembly;
a pump conduit connecting the pump to the valve assembly;
a recirculation conduit connecting the container to the valve assembly bypassing the bump; and
a dispense conduit connected to the valve assembly;
wherein each of the valve assemblies of each of the container assemblies is configured to be switched between a dispensing position and a recirculation position by a common actuator thereby closing off the respective dispense conduits; and
wherein at least some of the valve assemblies are configured to actuate an adjacent valve assembly.
8. The apparatus according to claim 1 , wherein in at least some of the valve assemblies are provided with a position indicator visually indicating whether the valve assembly is in the dispensing position or in the recirculation position.
9. An apparatus for selectively dispensing one or more of a plurality of liquids, the apparatus comprising a plurality of container assemblies, wherein each of the container assemblies comprises:
a container;
a pump operatively connected to the container;
a valve assembly;
a pump conduit connecting the pump to the valve assembly;
a recirculation conduit connecting the container to the valve assembly bypassing the bump; and
a dispense conduit connected to the valve assembly;
wherein each of the valve assemblies of each of the container assemblies is configured to be switched between a dispensing position and a recirculation position by a common actuator thereby closing off the respective dispense conduits; and
wherein the dispense conduits are connected to a common manifold for simultaneously dispensing a plurality of liquids.
10. The apparatus according to claim 1 , comprising a controller for operating the pumps and valve assemblies, the controller being arranged to register the time that has lapsed after a dispensing cycle and to initiate recirculation when said time exceeds a pre-selected threshold.
11. A method of preventing segregation of multiphase liquids in pump conduits, each of which are disposed between a separate container and a separate dispense conduit, the method comprising:
providing a valve assembly between each pump conduit and each dispense conduit;
providing a recirculation conduit between each valve assembly and each container;
coupling a common actuator to each valve assembly, wherein the common actuator is a driving axle extending through the valve assemblies;
isolating each dispense conduit and providing communication between each pump conduit and each recirculation conduit by shifting each valve assembly to a recirculation position with the common actuator;
pumping the liquids to recirculate the liquids via circuits formed by each container, pump conduit, valve assembly and recirculation conduit.
12. The method according to claim 11 , wherein the pumping of the liquids to recirculate the liquids is repeated intermittently.
13. The method according to claim 11 , wherein the liquids are recirculated in a direction opposite to a flow direction during dispensing.