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Johnson’s most notable contribution to temperature control was the automatic multi-zone temperature control system – a pneumatic system that used a bi-metal thermostat to control air flow through a nozzle and thereby operate a pilot regulator.
A pneumatic HVAC control circuit operates on air pressure (typically between 3 and 13 psi) and uses mechanical means (actuators) to perform control functions. [21] Pneumatic control systems are still used in many buildings, especially in metropolitan areas, because of their large base of installation throughout the 1960s and 1970s. [22 ...
A pneumatic thermostat is a thermostat that controls a heating or cooling system via a series of air-filled control tubes. This "control air" system responds to the pressure changes (due to temperature) in the control tube to activate heating or cooling when required.
During the design stage, the diagram also provides the basis for the development of system control schemes, allowing for further safety and operational investigations, such as a Hazard and operability study (HAZOP). To do this, it is critical to demonstrate the physical sequence of equipment and systems, as well as how these systems connect.
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An actuator is a component of a machine that produces force, torque, or displacement, when an electrical, pneumatic or hydraulic input is supplied to it in a system (called an actuating system). The effect is usually produced in a controlled way. [1] An actuator translates such an input signal into the required form of mechanical energy.
The pneumatic control signals are traditionally based on a pressure range of 3–15 psi (0.2–1.0 bar), or more commonly now, an electrical signal of 4-20mA for industry, or 0–10 V for HVAC systems. Electrical control now often includes a "Smart" communication signal superimposed on the 4–20 mA control current, such that the health and ...
The skills to repair/calibrate require understanding of electronic, control, pneumatic and light mechanical engineering Instrumentation has existed for hundreds of years in one form or another; the oldest manometer was invented by Evangelista Torricelli in 1643, and the thermometer has been credited to many scientists of about the same period.