STEMCO Capillary Switch

Fluid or Gas Filled Capillary Tubes

Capillary Tube Assembly

Not all Bulbs, Probes and Capillary Tubes use a fluid fill, some use a gas. There are a large number of different fluids and gases used. This is based on:

  • What material is being sensed for temperature
  • Temperature range of the switch
  • Other external requirements to the switch

There are also other engineering and design requirements that are taken into account when a fill material is chosen. A large number of capillary tubes use a variation of an alcohol fill. Some even have odors added so a leak can be detected.

More Information about Capillary Switches

No matter which style or model you choose, all of the capillary thermostat switches operate using the same physics. A fluid or gas is encapsulated in a metal and when the temperature changes it either expands or contracts. This change moves a diaphragm which is in touch with a snap action switch and either opens or closes a circuit.

STEMCO Capillary Switches

Our capillary style thermostat switches are high limit switches. A limiting device is installed in a piece of equipment with an adjustable or fixed temperature setting, 0-700°F, that when the temperature is met either opens or closes a circuit. These temperature switches are available as an automatic or manual reset. Capillary thermostats are typically installed as a back-up or secondary control to prevent the equipment from exceeding a specified temperature, high or low.

For more information about STEMCO capillary switches, click here to contact us.

More Information about Capillary Switches

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