This application provides a water chilling unit including a compressor and a condenser, in which an outlet of the compressor communicates with an inlet of the condenser through a compressor outlet pipeline, and a check valve with a magnet is also provided in a discharge pipeline. During normal operation of the water chilling unit, the check valve is maintained at the maximum opening through attraction of opposite magnetic poles, and when the water chilling unit stops operating, the closure of the check valve is cushioned through repulsion of like magnetic poles.

A pneumatic valve features a housing with an air chamber including a supply opening for compressed air, a connecting opening to an air cushion, and a discharge opening. An actuator with a movable closing element, comprising a plunger and a plate with a first sealing element, is positioned within the housing. The actuator includes a circuit board, an actuating element with an actuating portion and a bending portion, and a shape memory actuator element. In a non-energized state, the actuator element positions the actuating element to press the plunger against the supply opening, while in an energized state, it allows the first sealing element to close the discharge opening via an elastic element. A second sealing element closes the supply opening in a non-energized state and opens it under positive pressure when energized. A third sealing element, elastically connected to the second, closes the supply opening under non-positive pressure conditions.

A pneumatic valve comprises a housing with an air chamber having supply, connecting and discharge openings. An actuator with a movable closing element is arranged in the housing, featuring a plunger, which projects through the discharge opening with a plate and a first sealing element for closing the discharge opening with an elastic element which, in the activated state, presses said sealing element against the discharge opening The actuator is in the form of an SMA actuator, wherein the actuator element is configured to, in a non-energized state, bring the actuating element to a first state in which it presses the plunger against the supply opening, and to, in an energized state, bring the actuating element to a second state in which the actuating portion does not exert any force on the plunger, wherein a second sealing element is arranged in the air chamber and functions as a check valve.

A check valve is provided with an over-ride configuration whereby a poppet located above a valve seat seals against the valve seat in a check valve configuration under the influence of at least one of gravity and fluid pressure from above the valve seat. A flow configuration occurs when pressure above the valve seat is lower than below the valve seat thereby at least assisting in pulling the poppet off the valve seat and permitting flow. An over-ride configuration exists due to foot downwardly extending from poppet through valve seat to below a lower section of the valve housing to contact a surface to thereby push the foot upwardly (and the poppet off the valve seat) so that flow could proceed in a direction normally prevented by the check valve configuration.

Hydraulic fluid release valve assemblies are described herein. The hydraulic fluid release valve assemblies may include a hydraulic unit base with a hydraulic fluid return channel and a hydraulic fluid release valve that is at least partially inserted in the hydraulic fluid return channel. The hydraulic fluid release valve assembly may further include a driving assembly to contact with the hydraulic fluid release valve to apply a pushing force on the hydraulic release valve to open the hydraulic fluid release valve, and an electrically powered driver connected to the driving assembly, the electrically powered driver, when actuated, causes the driving assembly to move to apply the pushing force to the hydraulic fluid release valve.