Vacuum Sensors for Rough Vacuum (1 millitorr to 760 torr)
The vacuum pressure range from atmosphere to ultra-high vacuum (UHV) is over 16 orders of magnitude. To cover this range requires more than one sensor type. Rough vacuum can be defined from atmosphere to the low millitorr range. Vacuum gauge sensors covering this range can be direct measurement where the pressure acts upon the surface of a diaphragm or indirect where measurement is a function of a pressure dependent property of the gas such as thermal conductivity or ionization. Using the indirect method requires an adjustment factor for that gas if other than air.
The measurement range is the decisive factor for an appropriate vacuum gauge. The chart below shows the type sensors and models for the pressure range. The corresponding gauge controller is also provided in the chart for the proper sensor.
Types of Vacuum Sensors
Thermovac Transmitters
The operation of the THERMOVAC transmitters is based on the thermal conductivity principle after Pirani. S-versions offer set point relays for improved process control. The THERMOVAC series is equipped with a LED-ring (360°) showing the sensor status.
Principle of measurement
Thermal conductivity after Pirani
Measurement/display range 5·10-5 to 1000 mbar (1 millibar = 0.75 torr)
Thermovac TTR 101 Transmitters
The THERMOVAC TTR 101 N models use a thermal conductivity MEMS Pirani / Piezo solid state sensor combination. They are resilient to vibration and shock venting and provide superior accuracy and gas type independent readings between 10 mbar and 1500 mbar.
Principle of measurement
Thermal conductivity after Pirani combined with Piezo
Measurement/display range 5·10-5 to 1000 mbar (1 millibar = 0.75 torr)
CERAVAC Transmitters
The CERAVAC Capacitance Diaphragm Gauge (CDG) direct measurement of an Inconel diaphragm defection to measure vacuum pressure. They are resilient to vibration and pressure bursts and provide good resistance to corrosive process gases.
Principle of measurement
Capacitive diaphragm stainless steel sensor
Measurement/display range- 10-5 to 1000 torr
DI/DU200 Transmitter
These sensors excel through a high overload response as well as excellent corrosion and vibration resistance. These sensors have a wide measurement range due to the combines measurement principle.
Principle of measurement
Capacitive ceramic diaphragm sensor, piezo resistive diaphragm sensor
Measurement/display range-0.1 to 200 mbar or 1 to 2000 mbar
Graphix Series Vacuum Gauge Controller
Vacuum gauge controller with 1-3 channels for all active sensors. Graphix has a 3.5" TFT touchscreen interface, easy to read bar graph display and ability to test to detect leaks using a pressure rise test.
Readout selectable between mbar, Torr, Micron, Pascal or Psi
Up to 6 adjustable set points
Internal and external data-logging (USB port on the front) for configurati- on and real-time measurement data
Sensor control function (degas and zero adjustment)
Selectable languages: English, German, Chinese, Japanese
Display One. Display Two & Display Three Vacuum Gauge Display
Display One (Display Two or Display Three) Vacuum Gauge Displays provides cost effective display technology of vacuum pressures. The Display One can be used with any of the active sensor Leybold Vacuum sensors. Readout selectable between mbar, Torr or Pascal. Chart recorder 0-10V output provided.