Vacuum Switches

A vacuum switch is a mechanical or electronic device that performs an electrical switching contact function at a certain level of vacuum gas pressure. It is used for pressure control and safety interlock duties in a range of vacuum applications.

A vacuum switch may be used to control the pump and prevent it from operating at too high a pressure in a multistage turbomolecular pumping system.

The fore-line vacuum pump controls the fore-line vacuum pressure required for the turbomolecular pump to operate. When the fore-line vacuum pressure reaches the preset switching point, the vacuum switch closes a relay contact, allowing an electrical signal to be sent to the turbomolecular pump, forcing it to start.

Two separate switch points are typically provided to prevent a vacuum switch from becoming unstable and generating irregular oscillations as a result of measurement noise or pressure pulsing. These are often referred to as the setpoint and hysteresis values. 

When the vacuum pressure reaches the setpoint, the vacuum switch relay engages, and the normally open contact closes. However, it will reopen if the hysteresis value is exceeded. After the relay is de-energised, the desired state of the contact determines whether normally closed or normally open contacts are used.

In modern vacuum equipment design, vacuum switches are often integrated into vacuum measurement equipment. A vacuum transducer may include several independent mechanical or solid-state relay switches controlled by one or more vacuum pressure sensors. 

In semiconductor manufacturing equipment, a load lock is used to transfer wafers from ambient air pressure to the vacuum processing chamber. To prevent contamination from ambient air and particles, the vacuum gas pressure in a load-lock chamber must be carefully controlled. Typically, pressure and vacuum controls are used to regulate the pumping and ventilation cycles.

Accurate and repeatable vacuum pressure control and monitoring are critical in many vacuum processes and applications. In the commercial world, mechanical vacuum switches have given way to electronic vacuum switches.

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Model 35 Vacuum Switch

Description Diaphragm Vacuum Switch with a Choice of Normally Open or Normally Closed Contacts (SPST) For Adjustable Switching Pressure Range -200 to -900 mbar Max working Pressures of 10 bar...

FC Series Vacuum Switch

Description Flameproof ATEX Exd Switch with an Adjustable Change Over Contacts (SPDT) or (DPDT) For Adjustable Switching Pressure Ranges Up to 400 bar. 1/4″ BSP Female Thread (Others Available) Stainless...

Model 38 Vacuum Switch

Description Diaphragm Vacuum Switch with a Change Over Contacts (SPST) For Adjustable Switching Pressure Range -200 to -900 mbar Max working Pressures of 10 bar Over Pressure Limit 15 bar...

Model 37 Vacuum Switch

Description Diaphragm Vacuum Switch with a Choice of Normally Open or Normally Closed Contacts (SPST) For Adjustable Switching Pressure Range -200 to -900 mbar Max working Pressures of 10 bar...

Model 357 Vacuum Switch

Description Diaphragm Vacuum Switch with a Choice of Normally Open or Normally Closed Contacts (SPST) For Adjustable Switching Pressure Range -50 to -900 mbar Available Ranges – -50 to -500...

FC Series Compound Switch

Description Flameproof ATEX Exd Switch with an Adjustable Change Over Contacts (SPDT) or (DPDT) For Adjustable Switching Pressure Ranges Up to 400 bar. 1/4″ BSP Female Thread (Others Available) Stainless...

Pressure Switch 901 Prescal

Description  Adjustable pressure switch monitoring overpressure, vacuum or differential pressure of liquid and gaseous.  The pressure switch uses a scaled adjustment knob to enable the adjustment of trip and reset...