The CalorVal BTU Analyzer
The CalorVal analyzer model SNR690 is an industrial strength assembly consisting of a heated flame cell and integrated controller that continuously measures calorific values from 0 to 1300/2500 BTU/ft3 of gaseous streams of industrial processes.
The sample is drawn into the flame cell and mixed with Hydrogen fuel before introduction to the burner. Directly above the burner is a thermocouple used to sense the heat produced by the burning gases and vapors. A temperature detector converts this temperature rise into an electrical signal that is proportional to the concentration of gas.
The analyzer displays a uniform response to a wide range of combustible gases. These close response factors allow accurate measurements of gas mixtures with variable compositions.
To avoid condensation during sampling, the entire analyzer pneumatic assembly is heated up to 120°C. This eliminates both inaccurate readings as well as excessive maintenance time due to condensation and clogging.
It is suitable for monitoring many common gases and vapors. The analyzer is unaffected by the temperature of the process and can sample streams up to 700°C.
The CalorVal employs customer-supplied nitrogen to drive its integrated air-aspirated sampling system. This method is simple, has no moving parts and requires very little maintenance. Auto-calibration solenoids which allow remote activation of calibration tests are standard.
The microprocessor-based control unit controls the sample flow and monitors many other functions of the analyzer such as operating temperature, calibration and the flame. Deviations or malfunctions are signaled as service-needed or fault events via LEDs and relays.
The system includes six relays: single-pole, double-throw relays for Low Limit Alarm, High Limit Alarm, Fault; and single-pole, single-throw relays for Horn, Calibration-in-Progress and Service Needed. Other standard outputs include a 4-20mA analog output and an RS-485 serial port with Modbus RTU protocol. Digital remote access and control is available.
| Measurement Range | 0-1300 BTU/ft3 (equivalent to 48 MJ/m3 oder 13,4 KWh/m3) Optional: 0-2500 BTU/ft3 |
| Repeatability | ± 1% of full scale |
| Zero Stability | ± 1% per month |
| Span Stability | ± 5% per year |
| Response Time | T90 ≤ 10 Sekunden (measured from sample inlet) |
| Operating Temperature | 120°C |
| Power Requirements | 120 VAC +10%-15% 50/60 Hertz or 230 VAC +10%-15% 50/60 Hertz 400 Watts maximum, 200 Watt typical |
| Sample Gas Pressure | Nominal range: 0 to +70 mbarg Maximum deviation to nominal: ± 35mbar |
| Sample Flow Rate | Typical 1,3 l/min ± 0,5 l/min |
| Fuel Gas | Hydrogen min. 99,99% purity, inlet pressure: 2,8-3,1 barg Consumption: typical 25 ml/min, |
| Nitrogen | Clean, dry Nitrogen at 1,4 barg inlet pressure Consumption approx. 25 l/min |
| Combustion Air | Innlet pressure 1 barg, consumption 700-800 ml/min |
| Ambient Temperature Range | -20°C to +65°C |
| Relays | Six relays for: Low Limit Alarm; High Limit Alarm; Fault; Horn; Calibration-in-progress and Service-needed Rated 60 Watt maximum |
| Analog Output | 4-20mA, non-isolated, 275 Ω max. |
| Serial Interface | RS-485, half-duplex, Modbus RTU |
| Sample Train Material | Hard-coat aluminium, stainless steel, Viton |
| Enclosure rating | Standard: IP 54 (NEMA 12/13) for indoor use Optional: IP 65 (NEMA 4X), corrosion resistant, for outdoor use |
| Dimensions | 406mm H x 307mm B x 216mm T |
| Weight | approx. 20 kg |
| Approval | ATEX: Ex II 3(2) G Ex nA nC d IIB+H2 T4, Ta = – 20°C to + 65°C, IP 54 |
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