A safety valve which has two fluidically interconnected safety valves, each of which has a 4/2-way valve function. Each safety valve has a first connecting port and a second connecting port, which are connected to each other in such a way that a fluid flow through the two safety valves, controlled by means of a control valve, to a fluid-actuated drive is prevented if the two safety valves simultaneously adopt a first switching position and such a fluid flow is possible if both valves simultaneously have a second switching state. One safety aspect results from the fact that the above-mentioned fluid flow is also prevented if the two safety valves adopt different switching states.

A first relief valve chamber (3) of a main relief valve (10) and a second relief valve chamber (7) of an auxiliary relief valve (11) are provided in series in a valve case 1. The first relief valve chamber (3) includes a valve seat chamber (4) at the right and a valve chamber (5) at the left. A first valve member (30) in the valve chamber (5) is biased toward a valve seat member (18) in the valve seat chamber (4) by a first relief spring (40). A second valve member (48) in the second relief valve chamber (7) is biased toward a second valve seat (47) by a second relief spring (50).

A relief valve includes a housing including an internal flow passage through which a working fluid flows, and a relief port discharging the working fluid from the internal flow passage, and a valve body including a first pressure-receiving portion a second pressure-receiving portion receiving pressure with a pressure-receiving area that is larger than a pressure-receiving area of the first pressure-receiving portion, and a first recessed portion formed at the second pressure-receiving portion at an opposite side relative to a pressure-receiving surface of the second pressure-receiving portion and including a closed-end cylindrical shape. The relief valve includes a biasing force adjustment mechanism including a spring of which one end is held at the first recessed portion, a support portion retaining the other end of the spring and including a closed-end cylindrical shape, and a motor adjusting a rotational angle and causing the support portion to reciprocate.

A container and method for taking out contained product. The container comprises a container body, a pressure transfer channel, a control valve, a liquid taking channel and an outflow channel, the control valve contains a moving part. The moving part is at different positions along with variation of pressure applied to a variable pressure part, and connection and disconnection of the channels which between the pressure transfer channel and the outflow channel and between the liquid taking channel and the pressure transfer channel are determined by three positions of the moving part. The container can quantitatively take out contained product, is simple in structure and avoid the product to be oxidized or polluted.

A heating system can include certain pressure sensitive features. These features can be configured to change from a first position to a second position based on a pressure of a fuel flowing into the feature. These features can include, fuel selector valves, pressure regulators, burner nozzles, and oxygen depletion sensor nozzles, among other features.

A backflow prevention device with reduced pressure zone to be installed in water systems is provided and comprises a body provided with inlet, outlet and exhaust openings, a check assembly with a stem, an elastic element, and a plate, a mobile diaphragm or membrane adapted to interrupt the fluid connection between the outlet opening and inlet opening and between said inlet opening and exhaust opening, wherein said stem of said check assembly is stabilized with respect to said body, and said plate is slidably disposed along the stem and is cooperatively placed with the mobile diaphragm or membrane in order to interrupt the fluid connection between said inlet opening and said outlet opening.

A pressure relief device for a double isolation valve comprises a body with a valve cavity. The valve body has a pocket formed therein. A disc is disposed in the central section of the pocket. The disc is interposed between two spring-actuated seats. Each of the seats is in fluid communication with opposing valve sides. The pocket central section is in fluid communication with the valve body cavity. Each of the seats is provided with two different types of gaskets in series. In operation, reverse pressure causes retraction of the seats, thereby relieving valve body cavity overpressure.

A combined valve for insertion into an elongated bore of a power unit body of a hydraulic power unit may have an elongated carrier for receiving a relief and a check valve. The valve may also have a register arranged at a first axial position of a longitudinal axis of the carrier for calibration of the relief valve. The valve may also have a check valve coupled to the carrier at a second axial position along the longitudinal axis of the carrier. The valve may also have a relief valve coupled to the carrier at a third axial position along the longitudinal axis of the carrier. A minimal distance between the first and the second axial position may be less than a minimal distance between the first and the third axial position.

A system. The system includes a valve assembly. The valve assembly includes a first port, a second port fluidically couplable with the first port upon application of negative pressure at the first port, a third port fluidically couplable with the first port upon application of positive pressure at the first port, and a first check valve positioned between the first port and the second port. The system also includes a second check valve fluidically couplable with the third port upon the application of the positive pressure at the first port. The second check valve is positioned external to the valve assembly.

A regulator for establishing outlet fluid pressure. The regulator includes a valve body having a fluid pressure inlet in selective fluid communication with a fluid pressure outlet. A pilot pressure inlet is formed in the valve body and in fluid communication with a source of pilot pressure. Valving structure in the valve body establishes outlet fluid pressure as a function of pilot pressure. First adjustable structure within the valve body may establish a minimum outlet fluid pressure threshold without regard to pilot pressure. Second adjustable structure within the valve body may establish outlet fluid pressure offset relative to pilot pressure.