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  2. Pressure switch - Wikipedia

    en.wikipedia.org/wiki/Pressure_switch

    Industrial pressure switches may have a calibrated scale and pointer to show the set point of the switch. A pressure switch will have a hysteresis, that is, a differential range around its setpoint, known as the switch's deadband, inside which small changes of pressure do not influence the state of the contacts. Some types allow adjustment of ...

  3. Control system - Wikipedia

    en.wikipedia.org/wiki/Control_system

    When the temperature in the room (PV) goes below the user setting (SP), the heater is switched on. Another example is a pressure switch on an air compressor. When the pressure (PV) drops below the setpoint (SP) the compressor is powered. Refrigerators and vacuum pumps contain similar mechanisms.

  4. HVAC control system - Wikipedia

    en.wikipedia.org/wiki/HVAC_control_system

    The program features include time schedules, set points, controllers, logic, timers, trend logs, and alarms. The unit controllers typically have analog and digital inputs that allow measurement of the variable (temperature, humidity, or pressure) and analog and digital outputs for control of the transport medium (hot/cold water and/or steam ...

  5. Furnace (central heating) - Wikipedia

    en.wikipedia.org/wiki/Furnace_(central_heating)

    These furnaces were still big and bulky compared to modern furnaces, and had heavy-steel exteriors with bolt-on removable panels. Energy efficiency would range anywhere from just over 50% to upward of 65% AFUE. This style furnace still used large, masonry or brick chimneys for flues and was eventually designed to accommodate air-conditioning ...

  6. Safety valve - Wikipedia

    en.wikipedia.org/wiki/Safety_valve

    An oxygen safety relief valve DN250-safety valves. A safety valve is a valve that acts as a fail-safe.An example of safety valve is a pressure relief valve (PRV), which automatically releases a substance from a boiler, pressure vessel, or other system, when the pressure or temperature exceeds preset limits.

  7. Air preheater - Wikipedia

    en.wikipedia.org/wiki/Air_preheater

    Inside the ducting, the hot furnace gases pass around the preheater tubes, transferring heat from the exhaust gas to the air inside the preheater. Ambient air is forced by a fan through ducting at one end of the preheater tubes and at other end the heated air from inside of the tubes emerges into another set of ducting, which carries it to the ...

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    mail.aol.com

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  9. Pressure regulator - Wikipedia

    en.wikipedia.org/wiki/Pressure_regulator

    Pressure regulator for domestic water supply. Outlet pressure is set with the blue handwheel and shown on the vertical scale. A water pressure regulating valve limits inflow by dynamically changing the valve opening so that when less pressure is on the outside, the valve opens up fully, and too much pressure on the outside causes the valve to shut.