Embodiments of the invention provide a piston assembly for a control valve in a water softener system. The control valve includes a drive mechanism, one or more fluid passageways, and a seal assembly. The piston assembly includes a main piston moveably received within the seal assembly and including a first end and a second end opposite to the first end, and a shuttle piston moveably received within the seal assembly. The shuttle piston includes a first end and a second end opposite to the first end, and is configured to selectively engage the second end of the main piston to form a seal therebetween and to selectively move relative to the second end of the main piston to form an opening between the second end of the main piston and the first end of the shuttle piston, in response to movement of the main piston.

A valve for a hydrogen tank of a fuel cell vehicle includes a first open hole for communicating with a tank-side flow passage, a blocking body for blocking the tank-side flow passage, and a second open hole that allows the tank-side flow passage to communicate with a pipe-side flow passage formed at a pilot plunger. As the pilot plunger ascends in the state in which the first open hole communicates with the tank-side flow passage, the tank-side flow passage is blocked by the blocking body and subsequently communicates with the pipe-side flow passage via the second open hole, thereby reducing the size of a section in which a pressure difference occurs between the flow passages and reducing the time taken to eliminate the pressure difference, thus securing stable supply of hydrogen from a hydrogen tank to a fuel cell.

A valve for a hydrogen tank of a fuel cell vehicle includes a first open hole for communicating with a tank-side flow passage, a blocking body for blocking the tank-side flow passage, and a second open hole that allows the tank-side flow passage to communicate with a pipe-side flow passage formed at a pilot plunger. As the pilot plunger ascends in the state in which the first open hole communicates with the tank-side flow passage, the tank-side flow passage is blocked by the blocking body and subsequently communicates with the pipe-side flow passage via the second open hole, thereby reducing the size of a section in which a pressure difference occurs between the flow passages and reducing the time taken to eliminate the pressure difference, thus securing stable supply of hydrogen from a hydrogen tank to a fuel cell.

Embodiments of the invention provide a piston assembly for a control valve in a water softener system. The control valve includes a drive mechanism, one or more fluid passageways, and a seal assembly. The piston assembly includes a main piston moveably received within the seal assembly and including a first end and a second end opposite to the first end, and a shuttle piston moveably received within the seal assembly. The shuttle piston includes a first end and a second end opposite to the first end, and is configured to selectively engage the second end of the main piston to form a seal therebetween and to selectively move relative to the second end of the main piston to form an opening between the second end of the main piston and the first end of the shuttle piston, in response to movement of the main piston.

Embodiments of the invention provide a piston assembly for a control valve in a water softener system. The control valve includes a drive mechanism, one or more fluid passageways, and a seal assembly. The piston assembly includes a main piston moveably received within the seal assembly and including a first end and a second end opposite to the first end, and a shuttle piston moveably received within the seal assembly. The shuttle piston includes a first end and a second end opposite to the first end, and is configured to selectively engage the second end of the main piston to form a seal therebetween and to selectively move relative to the second end of the main piston to form an opening between the second end of the main piston and the first end of the shuttle piston, in response to movement of the main piston.

Embodiments of the invention provide a piston assembly for a control valve in a water softener system. The control valve includes a drive mechanism, one or more fluid passageways, and a seal assembly. The piston assembly includes a main piston moveably received within the seal assembly and including a first end and a second end opposite to the first end, and a shuttle piston moveably received within the seal assembly. The shuttle piston includes a first end and a second end opposite to the first end, and is configured to selectively engage the second end of the main piston to form a seal therebetween and to selectively move relative to the second end of the main piston to form an opening between the second end of the main piston and the first end of the shuttle piston, in response to movement of the main piston.

An isolation valve includes a flow restrictor in a passage and having an orifice and configured to provide a first, second, and third flow paths. A spring may bias the flow restrictor to an open position that opens the second flow path. A solenoid assembly may include a coil and an armature moveable between an extended position that moves the flow restrictor to close the first, second, and third flow paths, and a retracted position that opens the first flow path. The first flow path may include a path from a first reservoir through the orifice to a second reservoir. The second flow path may include a first flow direction from the first reservoir to the second reservoir via a second path, the second path including a space between the flow restrictor and the passage. The third flow path may include a second flow direction from the second reservoir to the first reservoir via the second path.

A first member having a first lock groove and a second member having a connection hole for insertion of the first member and a second lock groove opened to an inner periphery of the hole, are connected via a lock ring having a circular section and engaging with the grooves. An outer diameter of the ring under a load-free condition is set not less than a diameter of a groove bottom surface of the second lock groove. A reduced-diameter guide hole portion for guiding the ring to the second lock groove while reducing a diameter of the ring, is adjacently disposed short of the second lock groove in an insertion direction of the first member. A depth from an inner peripheral surface of the guide hole portion to a groove bottom surface of the second lock groove is set less than a radius of the circular section of the ring.