The pressure switch button is a switch form that closes the electrical contact when a certain fluid pressure has been reached at its input. Switches may be designed to make contact either on increasing pressure or decreasing pressure. Pressure switches are widely used in industry to automatically control and control systems that use pressurized fluids.
Another type of pressure switch detects mechanical strength; for example, pressure-sensitive mats are used to open doors automatically on commercial buildings. Such sensors are also used in security alarm applications such as pressure sensitive flooring.
Video Pressure switch
Construction and type
Pressure switches for sensing fluid pressure contain capsules, bellows, Bourdon tubes, diaphragms or piston elements that damage or move proportionally to the applied pressure. The resulting movement is applied, either directly or through the amplifier amplifier, to a set of switch contacts. Since the pressure can change slowly and the contact should operate quickly, some of the above mechanisms such as snap-action miniature switches are used to ensure fast operation of the contacts. One sensitive type of pressure switch uses a mercury switch mounted on a Bourdon tube; weight of mercury replacement provides above useful characteristics.
Pressure switches can be adjusted, by moving the contacts or adjusting the tension in the spring balancer. The industrial pressure switch may have a calibrated scale and pointer to indicate the set switch point. The pressure switch will have hysteresis, that is, the differential range around the setpoint, known as the deadband switch, where a small change of pressure does not affect the contact status. Some types allow for differential adjustment.
The pressure sensing element of the pressure switch can be set to respond to the difference of the two pressures. Such switches are useful when the differences are significant, for example, to detect clogged filters in the water supply system. Switches should be designed to respond only to differences and not to false operations for changes in common mode pressures.
Contacts from pressure switches can be rated a few tenths of amperes to about 15 amperes, with smaller ratings found on more sensitive switches. Often the pressure switch will operate relays or other control devices, but some types can directly control small electric motors or other loads.
Since the internal parts of the switch are exposed to process fluids, they must be selected to balance the strength and life expectancy of compatibility with process fluids. For example, rubber diaphragms are usually used in contact with water, but will rapidly degrade if used in systems containing mineral oil.
Switches designed for use in hazardous areas with flammable gases have a cover to prevent the arc in contact from triggering the surrounding gas. The enclosure switch may also be required for weather resistance, corrosion resistance, or submersible.
The electronic pressure switch combines several variations of pressure transducers (strain gauges, capacitive elements, or other) and internal circuits to compare measured stresses with set points. The device can provide better repetition, accuracy, and accuracy via mechanical switches.
Pneumatic
The use of pneumatic pressure switches include:
- Replace the household water well pump automatically when water is taken from the pressure tank.
- Turns off the electrically driven gas compressor when the set pressure is reached in the reservoir
- Turns off the gas compressor, whenever there is no feed at the suction stage.
- charge control in cells in battery
- Enables/disables the alarm light in the aircraft's cockpit if cabin pressure (based on altitude) is very low.
- Air-filled hose that activates the switch when the vehicle passes through it. Usual to calculate traffic and at gas stations.
Hydraulics
The hydraulic pressure switches have various uses in the car, for example, to warn if engine oil pressure falls below the safe level, or to control the torque of an automatic transmission converter. Prior to the 1960s, pressure switches were used in hydraulic braking circuits to control power to brake lights; newer cars use switches that are directly activated by the brake pedal.
In the dust control system (bag filter), the pressure switch is mounted on the header which will raise the alarm when the air pressure in the header is less than necessary. A differential pressure switch can be mounted across the filter elements to feel an increase in pressure drop, indicating the need for cleaning or filter replacement.
Maps Pressure switch
Example
Pressure sensitive base
A pressure sensitive mat provides a contact signal when the force is applied anywhere within the mat area. Some mats give a single signal, while others can complete the applied force position in the mat. Pressure sensitive mice can be used to operate electrically operated doors, or as part of an interlock system to ensure clean machine operators from hazardous areas of a process before operating. Pressure sensitive mice can be used to detect people walking above a certain point, as part of a security alarm system or to calculate attendance, or for other purposes.
See also
- Dynamic pressure
- Sensor list
- Sensor pressure
References
External links
Source of the article : Wikipedia
0 Comments