Provided are a maintenance-free gas density relay and a mutual check method therefor. The maintenance-free gas density relay includes a gas density relay body and first gas density detection sensors which are in communication on gas paths, and an intelligent control unit connected to the gas density relay body and the first gas density detection sensors separately, where the intelligent control unit compares and checks a first pressure value and a second pressure value acquired at the same gas pressure, and/or compares and checks a first temperature value and a second temperature value acquired at the same gas temperature, or compares and checks a first density value and a second density value acquired at the same gas density, and can further upload received data to a background for data comparison by the background. The present disclosure further completes online self-check or mutual check of the gas density relay while being used for monitoring gas density of a gas-insulated or arc-control electrical apparatus, thereby improving efficiency, avoiding maintenance, reducing cost, and ensuring safe operation of a power grid.

Provided are a maintenance-free gas density relay and a mutual check method therefor. The maintenance-free gas density relay includes a gas density relay body and first gas density detection sensors which are in communication on gas paths, and an intelligent control unit connected to the gas density relay body and the first gas density detection sensors separately, where the intelligent control unit compares and checks a first pressure value and a second pressure value acquired at the same gas pressure, and/or compares and checks a first temperature value and a second temperature value acquired at the same gas temperature, or compares and checks a first density value and a second density value acquired at the same gas density, and can further upload received data to a background for data comparison by the background. The present disclosure further completes online self-check or mutual check of the gas density relay while being used for monitoring gas density of a gas-insulated or arc-control electrical apparatus, thereby improving efficiency, avoiding maintenance, reducing cost, and ensuring safe operation of a power grid.

A pressure switch including a pressure chamber and a moving disc. The moving disc is moveable in response to a pressure in the pressure chamber to cause contact between a moveable contact and a fixed contact. An orifice communicates a fluid pressure into the pressure chamber. The orifice provides a tortuous path for a fluid flow to reach the pressure chamber. An oil supply system and a generator are also disclosed.

A pressure switch including a pressure chamber and a moving disc. The moving disc is moveable in response to a pressure in the pressure chamber to cause contact between a moveable contact and a fixed contact. An orifice communicates a fluid pressure into the pressure chamber. The orifice provides a tortuous path for a fluid flow to reach the pressure chamber. An oil supply system and a generator are also disclosed.

Embodiments of the disclosure provide an encapsulated compressor overload, an encapsulated compressor relay start, an encapsulated head pressure control switch and a wiring diagram for a circuit for air conditioning units which prevent gases from being ignited by means of encapsulating sparking components, use of solid-state switching devices, and/or wiring circuits in such a way that open contacts do not contain enough energy to produce a spark capable of igniting the atmosphere.

The application provides a gas density relay with online self-check function and its check method, which are used for high voltage and medium-voltage electrical equipment. The gas density relay includes a gas density relay body, a first pressure sensor, a temperature sensor, a force measuring sensor, a driving contact action mechanism and an intelligent control unit. The driving contact action mechanism is configured to directly or indirectly drive the signal action mechanism of the gas density relay body to displacement, so that the gas density relay body will have contact signal action. The intelligent control unit will detect the alarm and/or blocking contact signal action value and/or return value of the gas density relay body according to the density value when the contact acts. Checking the gas density relay can be completed without maintainer coming to the site, which improves the reliability of the power grid, improves the efficiency, reduces the operation and maintenance cost, and can implement the maintenance free of the gas density relay.

The application provides a gas density relay with online self-check function and its check method, which are used for high voltage and medium-voltage electrical equipment. The gas density relay includes a gas density relay body, a first pressure sensor, a temperature sensor, a force measuring sensor, a driving contact action mechanism and an intelligent control unit. The driving contact action mechanism is configured to directly or indirectly drive the signal action mechanism of the gas density relay body to displacement, so that the gas density relay body will have contact signal action. The intelligent control unit will detect the alarm and/or blocking contact signal action value and/or return value of the gas density relay body according to the density value when the contact acts. Checking the gas density relay can be completed without maintainer coming to the site, which improves the reliability of the power grid, improves the efficiency, reduces the operation and maintenance cost, and can implement the maintenance free of the gas density relay.

A diagnostic by-pass apparatus electrically connectable to a pressure switch, a roll-out switch, and a limit switch of a furnace is disclosed. Each switch has two electrical leads. The apparatus includes a housing, an enclosure in the housing, an electrical circuit in the enclosure, and a continuity indicator electrically connected to the circuit and electrically connectable to both leads of each switch, one at a time. The indicator is used to identify a defective switch when the by-pass apparatus is connected to both leads of the switch.

A pressure switch includes a pressure-resistant container, a contact mechanism, at least one airtight terminal, a diaphragm that is operated at first operating pressure and is restorable at restoring pressure lower than first operating pressure, a first pressing member that presses the contact mechanism due to the operation of the diaphragm and switches the contact mechanism to an open state, a pressure-receiving deformation member that is deformed and operated at second operating pressure higher than the first operating pressure, and is not restored even when the pressure decreases to atmospheric pressure after the operation at the second operating pressure, and a second pressing member that presses the contact mechanism due to the operation of the pressure-receiving deformation member and switches the contact mechanism to the open state. The first pressing member and the second pressing member are composed of an inorganic material without containing any organic material.

A safety pressure switch is presented. For avoiding pressure switch malfunction, the present disclosure presents a safety pressure switch comprising: a container shaped as a cylinder, the container comprising a fuse room comprising a fuse socket, a switch room, and a separator comprises a hole; a pressure switch disposed in the switch room; a fuse disposed in the fuse socket; and a first electrical line and a second electrical line connected to the pressure switch through the hole, wherein the separator separates the fuse room and the switch room, and wherein the hole connects the fuse room and the switch room, and wherein the fuse is installed in the first electrical line.