Thermocouple Vacuum Gauge Tube

Repeatable. Reliable. Cost-Effective.

Every Thermionics thermocouple vacuum gauge tube is individually calibrated to perform as every other tube of the same model, so tubes can be replaced without the need to recalibrate the gauge controller.


  • Each tube is individually calibrated
  • MilSpec models
  • Fast response time less than or equal to 1 second
  • Operating range: 1 mTorr–at
  • Measuring range: 1 mTorr–2,000 mTorr
  • Reliable, rugged, and low cost
  • Private labeling
  • Strict quality control standards
  • Interchangeable with other manufacturers’ tubes (see Gauge Cross-Reference Guide)
  • Controllers for multiple gauges
  • OEM and quantity discounts

Thermocouple vacuum gauges offer an economical method of vacuum pressure measurement with accuracy suitable for many monitoring and control applications as well as general laboratory use. Simplicity of operation, low cost and the inherent ruggedness of these gauges has led to their widespread general use for “time proven” dependability and zero maintenance.

Thermionics offers a wide range of thermocouple gauges to suit demanding scientific, industrial and process control applications. Three basic units offer a choice in cost, materials, and power supply requirements. Additional models are variable to satisfy specialized ranges and operating conditions as well as provide interchangeability with other manufacturers’ products.

All materials used in the tubes are vacuum compatible and satisfy moderate temperature and environmental requirements. Optional materials of construction are available to provide higher temperature excursions and greater resistance to environmental conditions.

We offer technical information and welcome consultation on the application of these gauges. Quantity discounts and private label packaging are available to OEM customers.

Ordering Information

Refer to the Gauge Cross-Reference Guide for industry equivalencies
Nickel-plated steel construction and 1/8″ NPT vacuum connection are standard

Model No.



Direct replacement for the Varian 531. Noble metal alloy thermocouple, excellent sensitivity and reproducibility. “Workhorse” for general use and easily calibrated for different gases.


Fast response, long-term stability, low filament contamination under normal use. Very low supply current requirements allow use with battery-powered gauge controller (see model TGC-100B on Analog Controllers page).


Same as TG-6343 except manufactured with tighter tolerances to achieve a high degree of repeatability from tube to tube.


Very stable response, MilSpec vibration resistance, low filament contamination rate.

Shipping weight for all of the above tubes is 3/4 lb.


Vacuum Fitting Connection

Model No.: /xx
User-specified vacuum fitting connection (ConFlat flange, VCR gas fitting, ISO/KF fittings, quick-disconnect, etc.).

Gauge Tube with ISO/KF Flange

Model No.: /KF-16 or /KF-25
Gauge tube with ISO/KF-16 flange (specify model number /KF-16), or gauge tube with ISO/KF-25 flange (specify model number /KF-25).

All-Stainless Steel Construction

Model No.: /SS
All stainless steel construction—the thermocouple gauges above are available in stainless steel. To order, use the standard tube model number and add the suffix /SS, e.g.: TG-500M/SS.

All-Stainless Steel Construction, Unthreaded

Model No.: /SSU
All stainless steel construction—the stainless steel thermocouple gauges are available unthreaded. To order, use the standard tube model number and add the suffix /SSU, e.g.: TG-500M/SSU.