The application provides a modification of gas density relay, a gas density relay with online self-check function and its check method for high-voltage and medium-voltage electrical equipment. The gas density relay includes a gas density relay body, a gas density sensor, a pressure regulating mechanism, a valve, an online check contact signal sampling unit and an intelligent control unit. The pressure is increased or decreased by the pressure regulating mechanism to enable the contact action of the gas density relay body. The contact action is transmitted to the intelligent control unit through the online check contact signal sampling unit. The intelligent control unit detects the alarm and/or blocking contact signal operating value and/or return value of the gas density relay body according to the density value of the contact action; the check of the gas density relay can be completed without maintenance personnel on site. It has remote reading function to realize free maintenance and significantly improve the reliability of the power grid and the work efficiency, as well as reduces the O&M cost.

The modification method for the gas density relay, the gas density relay with the online self-check function and the check method thereof provided by this application are used for high-voltage and medium-voltage electrical equipment, including a gas density relay body, a gas density detection sensor, a temperature regulating mechanism, an online check contact signal sampling unit and an intelligent control unit. Regulate temperature rise and fall of the temperature compensation element of the gas density relay body through the temperature regulating mechanism, which leads to a contact action of the gas density relay body, the contact action is transferred to the intelligent control unit through the online check contact signal sampling unit, and the intelligent control unit detects the operating value and/or return value of the contact signal of the gas density relay body based on the density value at the time of contact action. The gas density relay check can be completed without maintainer at the site, so as to realize free maintenance, greatly improve the reliability of power grid, increase work efficiency and reduce the cost.

A high anti-vibration gas density monitor is provided, including a monitor enclosure, a signal control mechanism, and an indication value display mechanism independent from the signal control mechanism which are provided in the monitor enclosure. The signal control mechanism includes at least one corrugated pipe, a sealed compensation chamber, a signal generator, and a signal regulation mechanism. The corrugated pipe is perpendicular to a side wall of a control casing. The monitor enclosure includes an independent sealed compartment used to mount the indication value display mechanism. The sealed compartment is filled with anti-vibration oil, or is hermetically filled with gas. The indication value display mechanism includes a Bourdon tube, a base, an end holder, a movement, a pointer, and a dial.

A fluid pressure actuated device for establishing electrical contact includes a first side and a second side each defining a respective cavity. A respective flexible membrane is positioned across each cavity. Each membrane has an outer side that carries an electrically conducting contactor. The contactors are electrically connected to a conducting connector that extends at least partially through the device. Each flexible membrane extends and withdraws moving the associated electrically conducting contactor in opposing directions when fluid pressure is increased and decreased in the associated cavity. Each membrane may have an undulating shape by including concentric frustum portions that narrow in opposite directions. The contacts may have neutral positions that are internal relative to outer surfaces of the device until fluid pressure is increased in the respective cavities causing extension by movement of the membranes.

A fluid pressure actuated device for establishing electrical contact includes a first side and a second side each defining a respective cavity. A respective flexible membrane is positioned across each cavity. Each membrane has an outer side that carries an electrically conducting contactor. The contactors are electrically connected to a conducting connector that extends at least partially through the device. Each flexible membrane extends and withdraws moving the associated electrically conducting contactor in opposing directions when fluid pressure is increased and decreased in the associated cavity. Each membrane may have an undulating shape by including concentric frustum portions that narrow in opposite directions. The contacts may have neutral positions that are internal relative to outer surfaces of the device until fluid pressure is increased in the respective cavities causing extension by movement of the membranes.

The present disclosure provides a contact signal acquisition circuit for online checking a gas density relay on site. The contact signal acquisition circuit for online checking a gas density relay on site includes a first connecting circuit and a second connecting circuit, the first connecting circuit connecting a contact of a gas density relay to a contact signal control loop, and the second connecting circuit connecting a contact of the gas density relay to a contact signal sampling interface of an online check device, where in a non-checking state, the second connecting circuit is disconnected, and the first connecting circuit is closed; and in a checking state, the first connecting circuit is disconnected, and the second connecting circuit is connected, so as to connect the contact of the gas density relay to the contact signal sampling interface of the online check device, guarantee that a contact action signal is not uploaded during checking and safe operation of a power grid is not affected, omit maintenance of the gas density relay, greatly improve benefits and improve reliable and safe operation of the power grid.

Systems, methods, and apparatuses for regulating the delivery of negative-pressure therapy are described. The system includes a negative-pressure source, an energy source, and a switch. The switch can include a first conductor electrically coupled to the negative-pressure source, a second conductor electrically coupled to the energy source, and a diaphragm having a first position electrically coupling the first conductor to the second conductor and a second position separated from the first conductor and the second conductor. The diaphragm is configured to move between the first position and the second position in response to a differential between a control pressure and a therapy pressure.

An expansion system for temperature detection by means of thermomechanical expansion and movement has an expansion receptacle, an elongate fluid line which is connected in a fluid-conducting manner thereto, and a switching means which is mechanically operatively connected to the expansion receptacle for the purpose of actuation of a switching process of the switching means at a settable actuation point. A working fluid is contained in the expansion receptacle and in the fluid line. Furthermore, an activation material which is formed to change, upon contact with the working fluid or upon mixing with the working fluid, said working fluid with regard to its volume and/or its flowability is contained in the expansion system.

An expansion system for temperature detection by means of thermomechanical expansion and movement has an expansion receptacle, an elongate fluid line which is connected in a fluid-conducting manner thereto, and a switching means which is mechanically operatively connected to the expansion receptacle for the purpose of actuation of a switching process of the switching means at a settable actuation point. A working fluid is contained in the expansion receptacle and in the fluid line. Furthermore, an activation material which is formed to change, upon contact with the working fluid or upon mixing with the working fluid, said working fluid with regard to its volume and/or its flowability is contained in the expansion system.

Disclosed is an intermittent pressure switch for pneumatic valves to control pressure relief valves in oil and gas producing operations by directing the valve to open and close based on pressure parameters (pre)set by the user. This enables oil and gas wells to produce based on formation pressure buildup. The inventive switch consists of a box containing a pressure switch programmable from 0 to 5,000 psi, a 3-port solenoid valve, 24 volt battery system, solar panel, solar control charger, pressure gauge, circuit wiring, and pressure fittings.