Specialized - Gauge Tube ·Gauge
Thermocouple vacuum-gauge tube designed for measuring gas pressure in vacuum systems, with approximately five-ohm thermocouple resistance.
A thermocouple-type vacuum-gauge tube designed for the determination of gas pressures in vacuum systems and vacuum enclosures.
The 1946 is a specialized thermocouple-type vacuum-gauge tube. Unlike standard thermionic valves, this device operates on thermoelectric principles to measure the thermal conductivity of residual gases, providing a direct electrical indication of vacuum levels within a system or enclosure.
The 1946 is constructed with a hard glass envelope made of Corning Code 772 Nonex glass. This material provides the necessary thermal and mechanical stability required for direct connection to high-vacuum systems. The physical interface to the vacuum system is made via a tubulation with a diameter of 3/8 inches.
The physical dimensions of the tube are as follows:
The tube is designed to be versatile in its installation, permitting mounting in any operating position.
The internal structure of the 1946 contains a heater element and an integrated thermocouple. The electrical connections are made via four flexible leads extending from the device:
The electrical ratings and characteristics of these elements are:
| Parameter | Value |
|---|---|
| Heater Voltage | 1.0 V |
| Heater Current | 0.07 A |
| Thermocouple Resistance (Approximate) | 5 ̩ |
During operation, the device must be kept within its thermal limits. The maximum rated ambient temperature is 50 °C.
The 1946 is calibrated to detect gas pressures across specific ranges, operating on the principle that the thermal conductivity of the gas changes with pressure, which in turn alters the temperature of the heater and the corresponding voltage generated by the thermocouple.
The tube's pressure measurement capabilities are categorized into two sensitivity ranges:
The device can detect and measure pressures across a broad span:
The region where the device exhibits its highest resolution and response is:
The 1946 is a specialized thermocouple vacuum-gauge tube housed in a Corning Code 772 Nonex hard glass envelope. Operating with a low-power 1.0 V, 0.07 A heater and featuring an approximate 5-ohm thermocouple, it provides reliable pressure measurements in vacuum systems. With four flexible leads for electrical connection and a 3/8-inch tubulation, it can be mounted in any position. It is capable of measuring gas pressures down to 10^-4 mm of Hg (0.1 Microns of Hg), with its greatest sensitivity concentrated between 1 and 10^-3 mm of Hg (1000 to 1 Microns of Hg), up to a maximum operating ambient temperature of 50 °C.
7-contact octal-family base
General specifications
Properties common to every published source and operating point.
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
1 physical section, each with unique specifications.
Section 1
No fixed ratings are recorded for this section.
Thermocouple vacuum-gauge tube with approximately 5-ohm thermocouple resistance.
Source-dependent data
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.
Data set 01
Published operating points and test conditions from this source.
Useful pressure upper
1000 micron Hg
Useful pressure lower
0.1 micron Hg
Closest sensitivity upper
1 mm Hg
Closest sensitivity lower
0.0001 mm Hg