FlowK is aimed specifically at sewage pumping stations though you may see other applications once you see what it does.

OK Process Validation Ltd director, Rob Hill, has several years’ experience of sewage pumping and has experienced most (if not all) of the potential issues. Although most pumping stations have systems to detect and alarm if pumps fail or if the well level reaches the point of spill, many other important events go undetected. Examples of this are:

  • Partially (or even, fully) blocked pumps
  • Partial blockages in pipework
  • Damage to pump impellers
  • Leaking non-return valves

Approximately 20% of stations we have visited exhibited one or more of these issues without this being detected. These stations were all nominally “OK” i.e. they were keeping the well level under control and there were no tripped pumps. However, these undetected problems result in underperformance which, in turn means:

  • Increased energy consumption – typically 50-70%
  • Premature wear of pumps
  • Reduced maximum flow rate which means…
  • Increased pollution risk

FlowK detects all of these problems and more besides. FlowK plays no part in the control of the station and cannot influence operations directly.

FlowK connects to:

  • The pump controls – so FlowK “knows” how many pumps are running and, if they are variable speed, what speed they are running at.
  • The station flow meter
  • A “well high level” switch

In the same way that an experienced operator “knows” his plant, FlowK “knows” what OK looks like for that particular pumping station. Specifically, FlowK is programmed with the normal flow rate for all combinations of pumps and speeds. This sounds complicated but is really quite simple.

FlowK works like this:

  • Every 30 seconds FlowK checks how many pumps are running and their speed.
  • FlowK knows what flow rate to expect so compares the actual flow to the expected flow.
  • If the two flow rates are out of agreement (high or low) by more than a programmed proportion then FlowK starts to make decisions.
  • Special algorithms ensure that false alarms are avoided.
  • Once FlowK has determined that the event is “real” then an alarm is issued.
  • Every 30 seconds FlowK writes important data to a memory card.
  • Every alarm is also recorded to the memory card.


FlowK has three basic alarms:

1. FlowK “LOW ALARM” – the actual flow is lower than the expected flow (for the present pumping conditions). There are a number of potential causes for this alarm including:

  • Blockages in the station pipework
  • Blockages in the rising main
  • Rags in the pump
  • Damage to the pump impellor
  • Leaking non-return valves

Whatever the root cause of the alarm it is certain that:

  • Energy consumption will be increased – typically by 50-70%
  • Pollution risk will be increased – because the station will be unable to meet its consent under storm conditions.

Prompt corrective action in response to the alarm will reduce wasted energy and reduce pollution risk.

2. FlowK “HIGH ALARM” – the actual flow is higher than the expected flow (for the present pumping conditions). The main potential cause of this alarm is reduced resistance in the rising main due to a burst.

3. FlowK “WHLF ALARM” – WHLF means “Well High and Low Flow” – FlowK has detected that the well level is high and that the flow is below a pre-set value. This would normally be the consented flow for the station. A WHLF alarm is serious as it means that a pollution event is imminent. Fortunately, WHLF alarms should be rare as almost all conditions which could result in WHLF will have been preceded by a FlowK LOW alarm (maybe many days, or even weeks before the storm which would cause the WHLF). Provided that the LOW alarm is acted upon, and corrective action taken, then the WHLF, and the consequent pollution event, will be avoided.

FlowK issues alarms via volt-free contacts in a relay interface. This would normally be connected to a telemetry outstation for remote monitoring. FlowK is also able to send alarms to a designated mobile telephone via a gprs modem.


The primary purpose of FlowK is to alert you to problems without you having to study vast quantities of data. However, we do realise that data is important so FlowK records important data to a memory card every 30 seconds. The supplied memory card will hold approximately 30 years’ worth of data.

Every day the data from the previous 24 hours are uploaded to a specific website (protected by password) where the data may be viewed graphically or downloaded to your own computer.

You may find that the data gives you a useful insight into how your station actually works under varying conditions. We have found that savings are often possible by optimising the station’s control philosophy once you can see what is actually going on.

For a full technical specification of FlowK click HERE

If you need more information please contact us.

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