A pressure switch is a device made to respond to a specific level of pressure by producing an output.
Electrical feedback is produced by the switch in response to changes in pressure. The switch's automated response is based on pressure. Its use is widespread, from businesses to homes and workplaces.
For instance, it is frequently used in commercial sliding door pressure panels, electronic gas compressors, well pump systems and security alarms.
A regular pressure switch and a differential pressure switch are very similar. But in this instance, the switch is turned on when it detects a pressure difference between two points.
Mechanical pressure switch and electronic pressure switch are the two main types of pressure switches. Their structures and the pressure sensing component they use are slightly different, but their operating principles are the same. Bellows, diaphragms, and pistons are the most frequently utilised sensing components.
How does it function?
Let's take a closer look at a primary pressure switch's structure before analyzing its operating system.
Following are the components of a pressure switch include:
(A) Micro-switch
(B) Operating pin
(C) Range spring
(D) Operating piston
(E) Insulated trip button
(F) Switch case
(G) Trip setting nut
(H) Inlet pressure
A pressure sensor and a switch contact are the two main components of a modern pressure switch. The switch contact starts or stops the electric circuit whenever the pressure level is reached.
A piston serves as the pressing sensing element in a mechanical pressure switch that also includes the essential parts. However, this operates on the same principles as devices that use bellows or diaphragms for sensing.
As seen, the components remain inside the switch case (F); the inlet pressure (H) moves against the operating piston (D); the resulting pressure moves the spring (C). The range of the spring can be adjusted to a set pressure that activates the switch. The operating pin (B) that is activated by the motion of the spring and piston, in turn, triggers the micro-switch (A). The micro-switch has two components — usually close contact (NC) and normally open contact (NO); when the pressure switch is triggered, the micro-switch enables the electric circuit, making the switch work. In the absence of pressure, the micro-switch’s electric contact remains NO; when the set pressure is reached, the micro-switch activates the NO electric connection, closing the circuit.
The difference in the Working of a Mechanical and Electronic Pressure Switch:
A mechanical pressure switch's physical mechanism is triggered by fluid pressure, as in hydraulic or water pumps, whereas electronic pressure switches function via electronic pressure sensors and an electronic circuit. Some switches do not allow for pressure point adjustment because it is pre-set.
Mechanical switches are known to be better at handling higher voltages and can operate without any additional power. Electronic switches, on the other hand, can be changed in order to alter the delay time, output signal, Deadband adjustability, turndown ratio, etc.
Selecting the Right Pressure Switch:
The user must consider the type of the process media, working pressure, temperature range, deadband or differential (the interval between the switch set and reset point), enclosure based on type of environment, and type of pressure switch based on application when choosing the best pressure switch. For instance, a piston design should be used for high-pressure applications, while a diaphragm-operated switch should be used for low-pressure applications. Get in Touch with Us!
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