Pressure Transient Monitoring
It has long been known that pressure transients can have an adverse affect on the integrity of pipelines. This is painfully evident when water hammer causes a pipeline to fail.
However, most pressure transients occur without ever being noticed and can cause incremental damage every time a transient occurs. Accumulated damage of this nature can significantly weaken the pipeline.
Accurately measuring the operating pressure in a pipeline is an important aspect of understanding the system hydraulics. There are two reasons why pressure should be monitored:
- To determine the presence and severity of pressure transients and ensure that they are not adversely affecting the condition of a pipeline.
- To understand how the operation of the pipeline affects the pressure.
Traditional Pressure Monitoring Techniques are Not Adequate
Conventional pressure monitoring technologies are not adequate to detect and quantify pressure transients. Current instrumentation cannot reliably record data at a sampling rate necessary to capture and plot the event or they flood the user with excess useless data.
Measuring pressure in a pipeline has been performed numerous ways with fairly simple, conventional technologies. With these technologies getting the data isn't always an easy task and the data they provide don't present a realistic understanding of the conditions in a pipeline. For instance pressure gauges can simply be installed on a pipeline, but must be manually read and recorded. Further, unless one is fortunate to obtain a reading at the peak of a transient, the conventional technology will often miss the transient profile. Chart recorders can also be used, but these devices require changing charts on a regular basis and manually interpreting and entering data.
Digital data loggers are an improved technique to monitor pressure. These devices can be set up to digitally record pressure at regular intervals and feed the data directly into a computer, but they still have limitations. Digital data loggers can miss the pressure transients. Even if a data logger is set to record a pressure reading every 1/4 of a second, it can still miss a pressure transient which may last 0.1 second, as is the case with some water hammer events. Further, if data loggers are set up to obtain readings at this frequency, they are recording nearly 350,000 readings a day. This is a tremendous amount of data that can quickly fill the instruments memory requiring significant management.
Traditional pressure monitoring technologies have one or more of the following flaws:
- They require ongoing manual labor to obtain the data and input it into a useful format.
- The exact time of pressure readings may be in error by several minutes. When trying to match specific events (like a wire break in a PCCP main) to a pressure reading, the timing must be accurate to a few seconds.
- Pressure transients may go completely undetected.
- To obtain high sampling rates, large volumes of data must be recorded which can quickly overwhelm a computer or its user with useless information.
System Meets Pressure Monitoring Needs
The transient pressure monitoring system provides an elegant solution to these challenges. It obtains high quality data on pressure transients without flooding computers with endless amounts of data during normal conditions. The system continuously monitors pressure and under normal operating conditions will only report a reading every few minutes (user defines the intervals). However, when a transient occurs in the pipeline, the device detects the transient and begins sampling at a high rate, up to 100 samples per second (100 hertz). This arrangement provides accurate readings on pressure that can be plotted over the duration of the transient event.
Another advantage of the system is that it can be integrated into the SoundPrint AFO acoustic monitoring system as part of a long-term pipeline management strategy.
With traditional pressure monitoring technologies the transient on the left would have been missed. However, with our system (right) the transient is recorded and accurately plotted.
If you would like to monitor your pipeline for pressure transients, please contact Pure Technologies and we will help you find a suitable monitoring solutions.