Disclosed is a method of applying a biasing force against a piston in a valve as the piston moves along a piston stroke axis in a first direction and an opposing second direction, the piston having a first axial end that is a distal end of the piston, the method including: moving the piston along a piston stroke axis in the first direction and the opposing second direction, wherein while moving the piston along the piston stroke axis: applying a first biasing force in the second direction against the first axial end of the piston from a first spring, and applying a second biasing force in the second direction against the first spring from a second spring.

Disclosed is a method of applying a biasing force against a piston in a valve as the piston moves along a piston stroke axis in a first direction and an opposing second direction, the piston having a first axial end that is a distal end of the piston, the method including: moving the piston along a piston stroke axis in the first direction and the opposing second direction, wherein while moving the piston along the piston stroke axis: applying a first biasing force in the second direction against the first axial end of the piston from a first spring, and applying a second biasing force in the second direction against the first spring from a second spring.

In one respect, the invention is an improved valve block design having minimal or no deadlegs that improves the efficiency of a system purge process. In another respect, the invention is a system incorporating said improved valve block design.

In one respect, the invention is an improved valve block design having minimal or no deadlegs that improves the efficiency of a system purge process. In another respect, the invention is a system incorporating said improved valve block design.

A thermostat includes a valve member. The valve member has an insertion hole. The insertion hole is constituted by a first protective member and a second protective member. A shaft of a jiggle valve extends through the insertion hole. The jiggle valve has a substantially spherical head connected to an end of the shaft. The head closes the insertion hole by contacting the peripheral edge of the opening of the insertion hole. The materials of the first protective member and the second protective member each have a Vickers hardness higher than that of the valve member, which is part of the valve member other than the protective members.

A thermostat includes a valve member. The valve member has an insertion hole. The insertion hole is constituted by a first protective member and a second protective member. A shaft of a jiggle valve extends through the insertion hole. The jiggle valve has a substantially spherical head connected to an end of the shaft. The head closes the insertion hole by contacting the peripheral edge of the opening of the insertion hole. The materials of the first protective member and the second protective member each have a Vickers hardness higher than that of the valve member, which is part of the valve member other than the protective members.

A valve is provided having first and second flow channels connected by a passage. A sealing device is operable to open and close the passage to control fluid flow between the first and second flow channels. The sealing device includes a first sealing body and a second sealing body through which the passages extends. The first and second sealing bodies are biased together by a spring to close the passage. The first sealing body is passively movable by fluid and actively movable by an electromagnetic device to open the passage to permit fluid to flow between the first and second passages.

A valve is provided having first and second flow channels connected by a passage. A sealing device is operable to open and close the passage to control fluid flow between the first and second flow channels. The sealing device includes a first sealing body and a second sealing body through which the passages extends. The first and second sealing bodies are biased together by a spring to close the passage. The first sealing body is passively movable by fluid and actively movable by an electromagnetic device to open the passage to permit fluid to flow between the first and second passages.

A dispensing tap for liquids includes a body connected to the neck of a container, a dispensing head with an outlet or mouth, and a throat connecting the body to the dispensing head. A shut off valve is configured for sealing engagement with the mouth of the dispensing head, and a piston is axially guided within the dispensing head. The piston includes a periperhal seal slidably engaged with an interior surface of the dispensing head, and a valve stem coupled to the shut off valve. The piston is selectively actuable between a normally closed position an open position. A spring is captured between the piston and the dispensing head normally biasing the piston and shut off valve to the closed position. A vent is in communication with an interior of the body and the vent is opened and closed with movement of the piston and shut off valve.

A purging system is provided for a multiple variety seed meter of a multi-variety planter. The purging system includes seed return valves that may be arranged for receiving seed that was removed from the seed meter. The seed return valves return the removed seed into corresponding appropriate seed storage compartments to allow a new seed variety to be delivered to the seed meter while reducing seed variety mixing in the seed meter. A pipe with a purge passage may extend from the seed meter to a purging hose that delivers the removed seed to the seed return valve(s). Each seed return valve may be a vacuum-actuated piston airlock valve assembly with a valve plunger that reciprocates to define seed collecting and releasing states of the valve.