What are pressure switches?
Pressure switches are mechanical or electrical switches that, actuated by the pressure of a liquid or gaseous medium, switch a second device on and off.
If you want to set up an irrigation system without a pressure switch, for example, the medium would only be watered if you turned the pump on and off manually for each watering process.
With a pressure switch, the pump is switched on and off automatically. The pump is switched on or off by predetermined pressures that are exceeded or not reached.
Where are mechanical pressure switches used?
Among other things, pressure switches are used to switch pumps, valves and compressors. They ensure that a predetermined pressure or fill level of a tank or pressure accumulator is not exceeded or fallen short of. For example, pressure switches can be found in use at petrol stations, in washing machines and in swimming pools.
How do mechanical pressure switches work?
The functional principle of the mechanical pressure switch is a pre-stressed spring with a membrane or a piston, which acts as a measuring element.
A low process pressure is absorbed by a large-area membrane. High pressures are absorbed by a small-surface piston.
To determine what pressure is required for the pressure switch to operate, use the preloaded spring. This can be screwed in with a screw. The further the screw is screwed in, the greater the effort required to activate the pressure switch. If the acting force ceases, the reset point is set.
When selecting the pressure switch, consider the maximum system pressure that will act on the pressure switch. The setting range should be smaller than the overload safety in order to be able to absorb pressure peaks.
How are mechanical pressure switches connected?
Mechanical pressure switches are connected to the pressure line via T-pieces with a ¼ inch connection thread. The pressure switch is often equipped with a barometer in order to be able to make an exact setting.
The mechanical pressure switch itself works without electricity. All that is needed is a power line that switches the pump on and off according to the mechanical impulses that the pressure switch outputs.