Most flow measurements are not regularly subject to maintenance after installation and commissioning. System with averaging pitot tubes, orifice plates and other DP flow elements utilize DP flow transmitters. These electronic devices are subject to changes in ambient temperature, operating pressure and long term drift. All factors can lead to considerable measurement errors particularly at smaller measured differential pressure values. These errors are typically only noticed during phases of plant shutdowns or at worst remain completely undected. In almost all cases the problem could be solved with a demand-oriented zero calibration of the DP transmitter.
This is exactly where the patented AccuFlo®Zero comes into play. It performs this important maintenance work - the zero point calibration - automatically whenever it is necessary. It is an ideal accessory for all differential pressure pressure based flow measurements.
Since the AccuFlo®Zero basically eliminates the residual zero point error of DP transmitter it increases total measurement range through a large increase in total accuracy at lower rates.
The AccuFlo®Zero is also easy to retrofit in existing installations and works with almost all makes of DP transmitters.
The AccuFlo®Zero offers practical advantage wherever
- The maintenance efforts for DP flow measurement system should be reduced and automated,
- Demand-oriented execution zero point calibration should be guaranteed,
- Error at small measured DP values have led to problems in the past
- Dynamic range and accuracy shall be increased without replacing the measurement
- Costs should be saved,
- Installation of a second differential pressure transmitter (split range system) has not yielded the desired success.
|Zero point calibration:||based on change of ambient temperature (interval adjustable, standard: 5 Kelvin)
based on change of operating pressure (interval adjustable, standard: 5 bar, absolute pressure has to be measured inside DP transmitter)
based on long term drift (interval adjustable, standard: 24 h)
|Duration of cailbration||ca. 30 s|
|Last measured value:||Held constant during calibration|
|Ambient temperatuer||−20 … 55 °C|
|Pressure rating:||PN 100|
|Wetted Parts:||1.4571 (AISI 316Ti)|
|Supply voltage:||24 V DC|
|Installation||Usually between DP transmitter and existing manifold|