Build-up monitoring

Build-up due to iron hydroxide deposition in groundwater is a common aging problem for operators. Iron(II) oxide dissolved in water oxidizes to iron(III) oxide which precipitates, e.g., in wells, pipes as well as in any flowmeter. If users don’t realize that build-up reaches critical levels, downtime due to interruptions of measurement signals or a clog in the process takes them by surprise. Moreover, the reduced pipe diameter causes pressure loss and thus energy loss leading to increased costs.

To solve these issues, Promag W 400 with the build-up index monitoring feature of Heartbeat Technology was installed in the customer’s water extraction pipe at the well.
The feature analyzes the distribution of conductivity in the measuring tube to compute an indexed value proportional to the build-up thickness. This allows to monitor the increase or decrease of build-up during operation or cleaning process. The indexed value is displayed between 0% and 100% (no vs. max. detectable build-up).

During two 12-month-periods, the build-up of iron hydroxide in the customer’s application was continuously monitored. Every second month, the build-up thickness was measured and compared with the index value. After 12 months, a cleaning was conducted and during another 12-month-period, the build-up index values and build-up thickness were compared. The results of the first year could be confirmed, proving that for the same fluid the values are identical and therefore repeatable.

Besides other parameters like pump performance loss and lower flow rate, the operators can now monitor the build-up index to estimate the optimal cleaning time of the well to avoid unexpected downtime. Furthermore, the feature reduces the duration of the cleaning process since the operator knows exactly when the device is clean.