Besides the measuring values Wobbe-Index and Air demand, the RHADOX 7300 / 7300 Ex Analyser measures Gas density and Heat value.
The determination of the Gas density is performed according to the method of Bernoulli (1730) who was using the dependency of a laminar gas stream through an orifice. Since temperature and pressure of the sample gas and the air are already levelled in the RHADOX™ mixing chamber, the ratio of the flow of both components in a second mixing chamber is used to measure the Specific Gravity. A reference measurement of ambient pressure and temperature at the location of the RHADOX™ analyser compensates the ambient influence. The result is a precise measurement of the Gas density.
The readings of Wobbe-Index and Gas density allow the calculation of the Heat value.
The RHADOX™ determines the measuring components Wobbe-Index and Air demand by measuring the residual oxygen after the oxidation. To achieve highly accurate measuring values, the parameters pressure and temperature have to be constant within low limits. By way of construction this is achieved with:
- A control unit to level the pressure of the Off-gas and Air
- A heat exchanger to level the temperature of the Off-gas and Air
- The patented mixing chamber and the also patented method of the catalytic oxidation.
Technical data
| Measuring System | RHADOX 7300 / 7300 Ex |
|---|---|
| Ex-classification | ATEX II 2G Ex px IIB+H2 T4 Gb X (Ex-Zone 1) ATEX II 3G IIB+H2 T3 (Ex-Zone 2) |
| Measuring components / -ranges | |
| Air demand | smallest measuring span 1,5 m3 Air / m3 Gas largest measuring span 30 m3 Air / m3 Gas |
| Wobbe-Index | smallest measuring span 5 MJ / m3 largest measuring span 120 MJ / m3 |
| Specific gravity (gas density relative to air) | smallest measuring span 0,5 largest measuring span 30 |
| Calorific value | smallest measuring span 5 MJ / m3 largest measuring span 140 MJ / m3 |
| Analogue signal port | 4* 4 … 20 mA, galvanically separated |
| Reproducability | |
| Air Demand & Wobbe-Index | 0,15 % - 0,2 % of the measuring value |
| spec. Gravity and Cal. Value | 1,0 % - 2,0 % of the measuring value |
| Long term drift | < 2 % of measuring value / Month |
| Temperature drift | < 0,02 % / K, relative to end of measuring range |
| T90-Time | 5…15 seconds, depending on viscosity of the measuring gas |
| Other data | |
| Display | 2* 16 digit illuminated LCD display showing measuring values and system parameters |
| Option | graphic display |
| Messages | 1 System message (Measuring value yes / no) 3 Messages (Indication of operating status) Service, Calibration, Error messages |
| Digital Communication | serial Interface RS232 |
| Option | Interface RS485 or Ethernet |
| Ambient operating temperature | from - 5 °C to + 45 °C |
| Operating temperature | from + 5 °C to + 60 °C Special version up to + 105 °C |
| Gas connections | |
| Inlet | 6 mm Ferrule pack |
| Outlet | 12 mm Ferrule pack |
| Gas flow volume | Measuring gas 20 … 100 Nl/h Instrument Air 50 … 500 Nl/h (depending on Air demand) |
| Gas presse (at Inlet) | Gas > 0,1 bar (g), max. 17 bar (g) Iinstrument air > 2 bar (g), max. 8 bar (g) |
| Power supply | 115 or 230 VAC / 50 - 60 Hz, 1000 VA |
| Protection class / Housing | IP65 |
| Dimensions | 1000 x 900 x 350 mm (hxbxt) |
| Weight | approx. 100… 155 kg depending on options and protection class |
| Options | Integrated catalytic remover of by-pass gas Auto-Calibration |
| Version: AMS RH7300 E V-2013-07 |