The THERMOVAC TTR 91 RN is an active Pirani transmitter for rough-vacuum monitoring and backing-line measurement. Its standard Leybold output covers 5 × 10⁻⁴ to 1000 mbar. The tungsten/rhenium filament is the standard general-purpose option.
Manufacturer THERMOVAC RN range photograph; the illustrated flange and connector are configuration examples.
Part of the Leybold THERMOVAC Pirani gauges family. Compare the range and other model options.
Tell us the configuration and quantity you need. Include your process requirements if you would like help with selection.
View quote listThe THERMOVAC TTR 91 RN is an active Pirani transmitter for rough-vacuum monitoring and backing-line measurement. Its standard Leybold output covers 5 × 10⁻⁴ to 1000 mbar. The tungsten/rhenium filament is the standard general-purpose option.
| Measurement principle | Active Pirani; gas-dependent thermal conductivity |
|---|---|
| Pressure range | 5 × 10⁻⁴–1000 mbar, standard Leybold analogue output |
| Filament material | Tungsten/rhenium |
| Typical accuracy | ±15% of reading from 1 × 10⁻³ to 100 mbar; poorer accuracy outside this band |
| Vacuum connection | DN16 KF, DN25 KF, DN16 CF and other documented connection variants |
| Signal / interface | Logarithmic analogue output; separate RS232 or RS485 versions |
| Supply voltage | 15–48 V DC nominal ±10%; limited-energy supply |
| Maximum power consumption | 1.5 W, analogue version |
| Operating temperature | +5 to +60 °C |
| Protection rating | IP40 |
| Bakeout temperature | 150 °C with electronics housing removed |
Pirani measurement depends on gas thermal conductivity. A nitrogen/air reading is not automatically the true pressure of helium, hydrogen or a changing mixture. Give Girovac the gas composition and working pressure so that the measuring principle, correction and material suitability can be checked.
Analogue gauges are offered with FCC68/RJ45 or 9-pin D-sub connectors. Digital RS232/RS485 variants use a 9-pin D-sub. The connector shape alone does not establish the output scaling or pin assignment. Relay and setpoint arrangements also vary with the full order code; select these with the gauge rather than treating every option as freely interchangeable.
The range brochure identifies GRAPHIX as a compatible controller family. Specify the standard or matched output, communication interface, controller input and cable together. GRAPHIX ONE provides one active-gauge channel; TWO and THREE provide more. A gauge is not supplied with a controller or mains supply unless stated in the quotation.
The measuring tube and electronics can be replaced separately with matching parts. Deposits and contamination can affect the reading; follow the manual for adjustment and servicing. Compare TTR 96 RN, TTR 97 RN by filament, useful pressure range and process compatibility.
Specification references: 300973763_002_C5, March 2026, pp8–15; THERMOVAC brochure 3610 0331 02, ordering matrix and compatibility table. Use the instructions matching the supplied part number and revision.
For a THERMOVAC TTR 91 RN quotation, send the required pressure range and units, process gas and vapours, connection, ambient and bakeout conditions, output or communication protocol, cable length and quantity. Include the existing gauge/controller part numbers, required switching functions, power supply and calibration test points. Girovac will confirm the configuration, included equipment, price and availability.
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| Manufacturer | LEYBOLD |
|---|---|
| Equipment type | Vacuum gauges & instrumentation |
| Measurement principle | Active Pirani; gas-dependent thermal conductivity |
| Pressure range | 5 × 10⁻⁴–1000 mbar, standard Leybold analogue output |
| Vacuum connection | DN16 KF, DN25 KF, DN16 CF and other documented connection variants |
| Signal / interface | Logarithmic analogue output; separate RS232 or RS485 versions |
| Maximum power consumption | 1.5 W, analogue version |
| Filament material | Tungsten/rhenium |
| Typical accuracy | ±15% of reading from 1 × 10⁻³ to 100 mbar; poorer accuracy outside this band |
| Supply voltage | 15–48 V DC nominal ±10%; limited-energy supply |
| Operating temperature | +5 to +60 °C |
| Protection rating | IP40 |
| Bakeout temperature | 150 °C with electronics housing removed |
Send the gauge model, pressure range and process details for calibration, replacement or compatibility advice.
Confirm the range, pressure reference, connection, electrical output and whether cables, a controller or calibration are included.
Availability, lead time and the applicable warranty are confirmed for your quotation. A catalogue listing does not reserve stock.
What to check in your quotation · Delivery · Returns and faults
Leybold THERMOVAC TTR 91 RN Pirani Vacuum Gauge
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Compare the stated conditions as well as the values. A missing specification is not a zero rating; confirm suitability with Girovac.
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