The flow computer pvt type C 621 is an universal energy/ immission and flow computer for steam, gas, flue gas and liquid.
This latest development by pvt technology GmbH can be customized in many details. For example, our universal pvt input cards enable individual and specific calculations and linearizations. Consequently, a wide range of special applications is possible.
All flow computers pvt type C 621 leave our factory pre-parameterised and tested ready for operation for the respective application and with a detailed electrical connection diagram created especially for your application.
The special features offered by the flow computer pvt type C 621 are difficult to implement with the process control system and require a great deal of programming effort. Therefore,more and more operators are opting for the more cost-effective and reliable isolated solution using our flow computer pvt type C 621. In addition, remote maintenance or remote diagnostics can be implemented via the optional Profi, M or Mod bus.
Traditional differential pressure method:
All coefficients of the flow calculation equation are calculated once in the design state and combined to a constant.
Improved differential pressure method:
In contrast to the traditional method, the coefficients of the flow equation (flow coefficient, pre velocity factor, expansion coefficient, density, etc.) are constantly recalculated according to ISO 5167. This has the advantage that the flow rate is determined exactly even under fluctuating process conditions far beyond the design state (temperature and pressure at the design point) and thus a higher accuracy in flow measurement is guaranteed.
The device only requires the following data for this purpose:
f = correction factor (correction of the measurement, e.g. to take account of pipe roughness)
Temperature influence on pipe inside diameter
The pipe data are often related to production temperature (approx. 20 °C) or process temperature. The data is automatically converted to operating temperature. For this purpose only the coefficient of expansion of the pipe material has to be entered.
When using dynamic pressure probes:
If pitot tubes are used, a correction factor must be entered instead of the diameter ratio. This factor is implemented for you by pvt technology when parameterising the C 621 according to the application.
The flow rate is calculated as follows:
*Note: Not all listed options are standard. Profi, M or Modbus, Ethernet, EX or special inputs are optional.