Piston Pump Arrangement Automatically Disabling in Absence of Inlet Liquid

A pump arrangement comprising:

• a first piston pump having a first chamber and a first piston reciprocally movable along a first axis in the first chamber to draw a first fluid into the first chamber from a first reservoir through a first conduit opening into the first chamber and discharge the first fluid out a first outlet,
• wherein reciprocal movement of the first piston discharges the first fluid from the first reservoir until the first reservoir is empty of the first fluid wherein further reciprocal movement of the first piston creates a vacuum condition in first chamber axially inward of the first piston,
• a driving member movable reciprocally parallel to the first axis,
• the driving member adapted to be coupled to an actuator which moves the driving member reciprocally parallel to the first axis,
• a releasable juncture arrangement releasably coupling the driving member and the first piston together, the releasable juncture arrangement having a coupled condition and an uncoupled condition,
• in the coupled condition, the releasable juncture arrangement couples the driving member and the first piston together such that reciprocal movement of the driving member parallel the first axis moves the first piston member parallel the first axis in unison,
• in the uncoupled condition, the releasable juncture arrangement does not couple the driving member and the first piston together such that reciprocal movement of the driving member parallel the first axis does not move the piston member rendering the first piston pump inoperative to discharge the first fluid by movement of the driving member,
• with the releasable juncture arrangement in the coupled condition, when the vacuum condition in the first chamber is greater than a threshold separation vacuum, the releasable juncture arrangement assumes the uncoupled condition.