Scientific Instruments -Model Series 56 -Cryogenic Temperature Probes
Scientific Instruments offers a variety of temperature probes that allow mounting in hazardous environments. These units are constructed of stainless steel, hermetically sealed, and the sensing element is mounted in a thermal epoxy at the tip. The probes are designed for direct immersion or thermowell applications.
The basic sensing elements used in the Series 56 temperature probe assemblies, designed, and manufactured by Scientific Instruments, are the SI-540 silicon diodes. These diodes are rugged, wide-range (1.5K to 450K) sensing elements which offer excellent interchangeability to standard temperature-versus-voltage curves. This interchangeability allows a user to employ any given temperature probe assembly in his facility while using a single temperature curve for signal conditioning requirements. This model has been used for cryogenic hydrogen applications, ground support, and flight hardware. See below for detailed specifications.
- Enclosure : All wetted areas are 316 SS.
- Insertion Length : Customer specified.
- Sensing Element : The sensing element is a silicon diode supported and contained in a closed housing.
- Media Connection : Boss seal per MS33656E4
- Temperature Range : Each unit is capable of operating within an environmental temperature range of 1.5 K (-271.66°C) to 400 K (126.85°C)
- Operating Current : The operating current of the unit should be 10 microamperes (µA) ± 0.1µA for the 56D units and 100µA ± 1µA for 56DX (the sensor excitation is supplied by an external signal conditioner).
- Service Media : The unit will operate in the following gaseous or liquid media where compatible with the sheath-housing material and within the temperature range of the unit: Alcohol Neon (Ne) Ammonia (NH3) Nitrogen (N2) Helium (He) Nitrogen teroxide (N2O4) Hydrogen (H2) Oxygen (O2) Hydrazine (N2H4) Unsymmetrical dimethylhydrazine (UDMH) Monomenthylhygrazine (MMH) Water (H2O)
- Repeatability : The unit is capable of repeating test parameter results under identical test conditions, within ± 0.1K (± 5 mVDC) at the boiling point of liquid helium and within ± 0.5K (1.2 mVDC) from 25 K to 400 K.
- Accuracy : The unit shall be accurate to within ± 0.25K (± 12.8 mVDC) from 1.5K to 25K and within ± 0.5K (1.2 mVDC) from 25K to 400K. (46DX and 46DX1, within ± 0.75K from 273K to 400K)
- Response Time : The unit shall respond within 63.2 percent of total temperature change, for a step change in temperature from 293.15 K ± 3K to 77.35 K ± 3K, within 15 seconds.