Troubleshooting: pressures and vibrations

Observation:

Shortly after the start of operation of a pump unit, serious damage occurred to a bypass valve (pressure regulated). 

The request by the team of engineers of the client was to research whether there were any peaks in pressure and/or irregularities in the operation of the equipment.  

Monitoring configuration:

A trend will be built in the EX zone with an ATEX certified sensor (sample speed: 2s). If irregular patterns occur in the operation of the trend, the monitoring device will use high resolution data (Sample speed: 200µs).

Outside the EX zone, the device will be monitoring trends (via zener-barriers) for several weeks.

During this period, the different operating conditions of the equipment will be shown.

Result:

During the trending, an event occurred related to extreme low suction pressure and extreme high vibrations. In view of the low suction pressure, meaning the vapor pressure of the fluid to be pumped, the measurement of the flow rate was conducted in the suction pipe. This resulted, among others, in the following trend:

The high resolution data of the problem areas are shown in the diagram below:

Conclusion:

The monitoring of the pump has made it possible to explain the problem areas of the pump. As expected, pressure fluctuations occur that can be linked to specific operating conditions.

The monitoring has also clarified why pressure fluctuations occur. As the pressure in the suction pipe decreases due to low vapor pressure, gas bubbles are formed. In consultation with the company concerned, scenarios were established to avoid this condition in the future.