DESCRIPTION

All devices of the COMBIMASS® eco series are characterized by very effecient digital electronics. Important features of the electronics for practical application are the temperature compensation and the choice of different measuring modes (constant power or constant temperature). The electronics of the COMBIMASS® eco are placed in a compact, pressure-resistant stainless steel housing with a separate terminal compartment. Optionally, an 8-digit display with control panel for displaying the current flow rate or total value and for simple on-site operation of the transmitter is also available for these housing versions.

For the transmission of the flow signal an isolated 4-20 mA analogue output, a freely parameterisable pulse output or Modbus can be used. Each system is calibrated before delivery in our CAMASS® Calibration Lab, taking into account the actual operating conditions with regard to gas composition and installation situation (internal pipe diameter, pipe orientation, etc.). As a reference, officially calibrated measuring sections, standard orifices and precision inclined tube manometers are used. In addition, calibrated pressure and temperature transmitters enable the exact determination of operating conditions and volume flows on site. These measuring instruments are regularly checked by external laboratories as part of ISO quality assurance. State-of-the-art computer and simulation programs based on decades of experience are used to calculate the calibration data and to determine the correction factors for the temperature compensation.

A special application is the measurement of wet biogas directly downstream of the digester in sewage treatment plants. The moisture content of the biogas is detectec by the sensor too, and therefore the standard volumetric flow rate according to DIN 1343 cannot be detected directly, because the requirement 0% relative humidity is not met. However, the maximum waterdamp portion depends on gas temperature only and represents a known correlation. The temperature information of the reference electrode can be used in waterdamp-saturated biogas to calculate the proportion of water in the gas and compensate directly in the device without further analysis / correction modules.

If the measurement location is selected appropriately (e.g. for detecting gas production), the dry gas quantity can also be determined for humid biogas at standard conditions. Thermal gas flow meters are particularly suitable here compared to all other measuring methods (e.g. Vortex, Ultrasound, Mechanical counters), as they measure very precisely even at low gas velocities and pressure. An additional advantage is that all required compensations can be carried out directly in one measuring instrument.