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SKU: 254-000000-XXX

Notes: See product sheet for other seal materials.

Product Description

HST High Sample Temperature Safety Shutoff Valve

HST Product Sheet
HST Installation and Maintenance Instructions


  • Protects expensive and delicate sample analyzers
  • Automatically resets when sample cools
  • No outside power required
  • Superior value vs. more expensive electric valves
  • Easy installation

Design Features

  • Self-operating thermal actuator controls flow based on fluid temperature
  • Operating temperatures unaffected by variable inlet pressures
  • Wide choice of setpoints available
  • Ram-type plug provides tight shutoff
  • Corrosion resistant: all stainless steel construction


The HST High Sample Temperature Safety Shutoff Valve is used to sense the sample temperature after the sample cooler. The sample passes through this normally open valve whenever the sample temperature is below the valve setpoint. If the sample temperature exceeds the valve setpoint, the HST closes to protect expensive and delicate analyzers and other instruments from overtemperature damage. When the HST cools below the setpoint, it will automatically reset open again. Low coolant flow or total loss of cooling water or unusually high sample temperatures are typical reasons why the HST self-operating protective device should be considered.

Typical Applications

Excessively hot samples can cause damage to expensive and sensitive hardware and electronics. For process analyzers and similar instrumentation, it is important to assure that the process samples fluids are always below the maximum allowable temperature for such instruments. Sample coolers are commonly used to reduce sample temperatures to the acceptable limits. In the event of a loss of cooling fluid to the sample cooler, or if the desired sample temperature is exceeded for any reason, the HST valve will close to prevent equipment damage.

HST Typica Iinstallation