ACCURRA-TCD measures nitrogen mixed with hydrogen, helium or argon by thermal conductivity, with no reference gas. It cannot measure nitrogen in oxygen, air or CO, whose conductivities are nearly identical. For generator purity, measure residual oxygen with ACCURRA-S.
Specifications
| Item | Specification | Notes |
|---|---|---|
| Gas | Nitrogen in a binary mixture | |
| Sensor | Platinum thermal conductivity | |
| Repeatability | Below 1 % of full scale | Linearity below 1 % of range |
| Errors and drift | Below 1 % of full scale per week | |
| Response time | T90 below 10 s at 0.6 LPM | |
| Reference gas | Not required |
From the current Sarvesh product datasheets and company profile. Specifications may change without notice as products improve. The final responsibility to check that a product meets the process and analyser requirement remains with the customer.
Key features
- Binary nitrogen measurement in H2, He or Ar
- Isolated 4-20 mA, programmable alarms, Modbus RTU
- No reference gas
How it works
Nitrogen has an intermediate thermal conductivity. It differs strongly from hydrogen and helium and moderately from argon, so mixtures of nitrogen with those gases are well suited to TCD. Nitrogen, oxygen and carbon monoxide are very close, so nitrogen in oxygen or in air cannot be measured this way.
Typical uses are nitrogen-hydrogen atmospheres in annealing and float glass, nitrogen in helium and argon, and nitrogen purity checks where the impurity is a different, thermally distinct gas.
Requirements and limits
- Binary mixtures only; nitrogen in oxygen or air is not measurable by thermal conductivity.
On site: utilities and calibration gases
What to have ready at your plant before installation and commissioning.
| Item | Requirement | Notes |
|---|---|---|
| Power at the analyser | 100 to 240 V AC, 50/60 Hz, 45 W | |
| Zero gas | Zero-grade nitrogen, 99.999 % | 10 litre cylinder with regulator |
| Span gas | The measured gas at zero grade, 99.999 %: hydrogen, helium, argon or nitrous oxide | 10 litre cylinder with regulator |
| Sample at the analyser | 2 to 10 psig, 0.6 LPM, 5 to 40 °C, dust below 3 micron | Pressure and flow regulated by the user |
| Mounting | 19 inch rack or panel, in a safe area |
Selection guidance
Choose ACCURRA-TCD for nitrogen mixed with hydrogen, helium or argon. For nitrogen purity of a PSA generator, measure the oxygen impurity with ACCURRA-S 3015 instead, since oxygen is the main residual.
Applications
Application pages where this is part of the recommended solution:
Compatible products
ACCURRA-TCD
Thermal conductivity analyser for binary mixtures of H2, He, Ar, N2 and others, with no reference gas.
View ACCURRA-TCD
ACCURRA-S
Online analyser for trace, percent and purity O2, CO, CO2, CH4 and dew point; can measure two gases from one sample.
View ACCURRA-SHeadline filters
Particulate, coalescing and PTFE membrane filters from Headline Filters, UK, for analyser protection.
View Headline filtersFrequently asked questions
Can I measure nitrogen purity?
For a generator, measure residual oxygen with ACCURRA-S 3015, which is the more sensitive indicator.
Can it measure nitrogen in air?
No. Nitrogen and oxygen conduct heat almost equally.
Does it need a reference gas?
No.
Which mixes are listed?
Nitrogen in argon, carbon dioxide or hydrogen, on 0 to 100, 0 to 5 or 96/97 to 100 percent ranges.