A check valve can include a valve body defining a valve bore, the valve body comprising an annular body and a cross member secured to and extending in a radial direction across the valve bore from the annular body on one side of the valve body to the annular body on an opposite side of the valve body, the valve bore at the cross member divided into more than one portion by the cross member; a position block extending from the cross member; a pair of valve members, each valve member of the pair of valve members positioned within the valve body and configured to rotate between open and closed positions; and a pivot pin positioned within the valve body and extending through the position block and each valve member of the pair of valve members, the pivot pin being supported only by the position block.

A fuel system is provided that includes a fuel tank, a heat detector, and a control circuit. The digital heat detector is disposed in proximity to the fuel tank. The control circuit is coupled with the digital heat detector and is configured to detect that a thermal event has occurred. The fuel system is configured to implement an emergency countermeasure in response to the detection of the thermal event.

A dual plate backflow and breakaway check valve designed to mount above grade. The dual plate check valve includes a barrel assembly having an upper portion, a lower portion and an annular groove. An upper dual valve includes an upper front plate and an upper back plate. A lower dual valve includes a lower front plate and a lower back plate. A lower valve keeper bar moves up from between a plurality of lower valve stay tabs upon breakage of the annular groove thereby allowing the lower front plate and the lower back plate to rotate about a lower valve pin and closing the lower dual valve upon a lower barrel bevel and simultaneously allowing the upper front plate and the upper back plate to rotate about an upper valve pin and closing upon an upper barrel bevel.

An emergency shut-off device comprises an activation means configured to generate an activation force in response to detecting a seismic event, and a magnetic driver having a hollow guide tube with two magnets affixed at a selected position on opposite sides along a length of the guide tube with like poles facing each other and a drive piston movable inside the guide tube. The driver piston is coupled to a third magnet and has a first end for receiving an activation force to move the third magnet crossing a magnetic repulse shift line formed by the two magnets, and a second end for applying the drive force to an output system to effectuate a shut-off of a fluid line.

An emergency shut-off device comprises an activation means configured to generate an activation force in response to detecting a seismic event, and a magnetic driver having a hollow guide tube with two magnets affixed at a selected position on opposite sides along a length of the guide tube with like poles facing each other and a drive piston movable inside the guide tube. The driver piston is coupled to a third magnet and has a first end for receiving an activation force to move the third magnet crossing a magnetic repulse shift line formed by the two magnets, and a second end for applying the drive force to an output system to effectuate a shut-off of a fluid line.

An actuation system for a valve is disclosed. The actuation system comprises a housing having an end wall. A first piston and a second piston is slidably positioned within the housing. The second piston is positioned between the first piston and the end wall. A piston rod is coupled to the first piston and slidably extends through the second piston and the end wall. The piston rod is configured to be coupled with the valve. A first spring is arranged between the first piston and the second piston. Further, a second spring is arranged between the second piston and the end wall. The first spring and the second spring are configured to bias the valve to a closed position.

A gas shut-off valve assembly designed to automatically close gas flow in a gas conduit in response to a seismic vibration comprises a door which may be parallel to a port in the conduit and a weight above the door. In some embodiments, the door may be mostly out of the conduit passageway and out of the gas flow allowing for improved gas flow efficiency in the normally open state. Upon sensing a seismic vibration, the weight falls from a platform onto the door causing the door to move into the conduit passageway sealing the passageway. In some embodiments, a port in the passageway is perpendicular to the door's default position in the open state. When the door closes the passageway, the door rotates ninety degrees about an axis into the second closed position to become parallel with the port.

A valve assembly for controlling fluid communication between fluid chambers in a device such as an inflatable device includes a valve body having first and second ports for fluidly connecting to first and second fluid chambers, and defining a plurality of primary valve seats in series between the ports. A plurality of compound valves are within the valve body and each includes a primary valve member movable to close or open one of the primary valve seats, and a secondary valve member movable to close or open a secondary valve seat in the primary valve member.

A valve assembly for controlling fluid communication between fluid chambers in a device such as an inflatable device includes a valve body having first and second ports for fluidly connecting to first and second fluid chambers, and defining a plurality of primary valve seats in series between the ports. A plurality of compound valves are within the valve body and each includes a primary valve member movable to close or open one of the primary valve seats, and a secondary valve member movable to close or open a secondary valve seat in the primary valve member.

An explosion isolation device is disclosed. The explosion isolation device may comprise a conduit having a flap configured to rotate between an open position and a closed position within the conduit, and a holding mechanism configured to hold the flap in the open position. The holding mechanism may be configured to release the flap in the event of an explosion and the flap may be configured to rotate into the closed position after it is released. The device may include a sensor and an actuator configured to actuate the holding mechanism when an explosion is sensed. The conduit may be vertical.