Some possible applications with pressure switches
Short list of applications
HVAC Air Prover (Low Pressure)
HVAC systems must ensure that air is flowing before turning on heating elements or gas burners. A pressure probe perpendicular to airflow can prove fan operation. Probe is placed in the duct, downstream from the fan. Switch will not permit burner ignition (or energizing of coils) unless sensor detects positive air flow.
HVAC Air Prover (Vacuum)
Fan operation or air flow can be confirmed using vacuum, by locating the pressure probe to detect falling pressure at the intake, or suction side of the fan.
HVAC Air Prover (Static Pressure)
Perpendicular and parallel probes can be located to detect varying amounts of positive static pressure, proving fan operation and/or true air flow.
HVAC Filter Indicator (Pressure)
A pressure probe located downstream of the fan, but upstream of the filter detects positive pressure limit reached as filter gets dirty. Switch activates indicator light, alerting need for filter change.
HVAC Filter Indicator (Vacuum)
A pressure probe downstream of the filter, but upstream of the fan detects negative pressure limit reached as filter gets dirty. Switch activates indicator light, alerting need for filter change.
HVAC Filter Indicator (Differential)
Pressure probes located on opposing sides of the filter element will detect high differential pressure reached as filter gets dirty. Switch activates indicator light, alerting need for filter change.
Reservoir Level Control
Falling liquid level produces vacuum in indicator tube. Sensor detects pressure drop, starts pump. As reservoir fills, sensor detects increase, stops pump.
Oil/Hydraulic Filter Alert
As dirty oil or fluid loads filter element, housing pressure rises. Sensor detects increase. Switch activates light, alerting operator of need for filter maintenance.
Fuel Dispenser Auto-Shutoff
Sensor in fuel dispenser handle detects increasing pressure, caused by liquid rising in filler neck. Switch disables dispenser pump, preventing overflow.
Overhead Door Safety Detector
Tube edge transmits pressure increase if overhead door strikes an obstacle, and is not within limit distance of floor. Switch reverses motor, raising door safely.
Process Break Detector
Air jet and probe are located on opposite sides of process. Probe does not detect jet unless process material (sheet, roll, reel, etc.) parts or ends. Switch turns on indicator light, alerting process break.
Respiratory Sensor
Sensor detects patient's aspiration. Switch activates regulated supply of oxygen, dispenses vapor, medicates, or controls other respiratory therapy.
HVAC/R Defrost Sensor
Probes located on opposite sides of refrigeration or cooling coils detect change in differential pressure caused by icing of coils. Switch alerts condition, or starts defrost cycle.
Tire Pressure Monitor
Valves with integral pressure probe monitor tire pressure. If pressure falls below limit, indicator light alerts need for tire pressure maintenance.
Auto Emission Control Valve
Sensor inside EGR valve detects absolute pressure in engine intake manifold, enables exhaust gas recirculating emission control valve.
Sip and Puff Movement Control
Sip and puff aspirations allow a severely disabled person to orally actuate bed position, wheelchair movement, or other forward-reverse motorized controls.
Non-Electric Spa Pump Control
Air button transmits pressure change via tube to sensor, which activates switch, controlling spa pump motor. Non-electric system avoid shock hazard.
Frictionless Air Bearing
Sensor controls pressure of compressed air supplied to air bearing, providing frictionless, wear-free handling of audio, video, or computer storage tape.
Tape Braking System
High speed tape runs over vacuum braking grid on a film of air pressure. When pressure is changed to vacuum, tape stops instantly, avoids distortion.
Venting Hood Monitor
Sensor monitors air flow above exhaust fan in fume venting hood. If fan fails or becomes inefficient, switch activates light to alert condition, or inhibits fume-creating process.
Dairy Systems
Sensors monitor dairy system vacuum levels, can control milking machines, milk transport, and storage-increasing efficiency, automation, and sterility.
Therapy Tent Nebulizer
Venturi draws medication from vessel. Nebulizer supplies fog to therapy tent. Sensor monitors medication level by controlling pressure of air flow.
Blood Pressure System
Switch controls inflation pressure of automated sphygmomanometer cuff, tourniquet cuff, anti-shock trousers, blood-taking equipment, etc.
Easy pressure controll
To recognize a pressure threshold a simple mechanical pressure switch is mostly sufficient. There are countless applications possible.
