Pipeline companies utilize cathodic protection to overcome external corrosion concerns. Owner interest in extending the life of the asset also generally includes addressing safety grounding concerns, which are typically accomplished by solid-state decoupling products. Together, cathodic protection systems and decouplers address the multiple needs of corrosion prevention, isolation of CP from other structures, and safety grounding.
Dairyland’s latest innovation in solid-state decoupler technology represents a leap forward in decoupler technology. Using sophisticated design techniques that represent the work of numerous leading experts around the world, the PCRX’s camouflage technology renders it completely invisible to interrupted survey testing. This is a major technological advancement that provides a direct benefit to customers experiencing inaccurate readings due to capacitance from decouplers installed on their pipeline.
Understanding Interrupted Survey Interference Issues
Corrosion prevention is efficiently provided by impressed current systems, and system effectiveness is regulated on most major pipeline systems by governmental authorities, such as the Department of Transportation (DOT) in the United States. Such compliance, as well as pipeline owner self-interest, is proven by various measurements, some of which include coating surveys and potential measurement surveys. 
For safety and convenience, decouplers remain connected to the pipeline while the interrupted surveys are being performed, and in some cases the user may see unexpected results in the potential survey. Waveforms depicting the pipeline potentials over time may show a more slowly decaying potential during the off cycle, and likewise a slower response during the on cycle when the GPS interrupters turn the rectifiers back on. The resulting time-based absolute potential values during the off cycle therefore will not be as expected, appearing too electronegative. As cathodic protection compliance is based on such measurements, this can confuse the user and raise questions about their system operation.
PCRX – Extreme Decoupler Performance
Thousands of hours of research, development and field testing have resulted in a new innovation in decoupler technology designed to create an improved user experience for corrosion professionals experiencing these challenges.
The PCRX performs all of the expected Dairyland decoupler safety and isolation functions, and adds sophisticated solid-state systems to provide a correct CIS response. The PCRX is effectively camouflaged, invisible to changing potentials during a close interval survey, yet still accomplishes mitigation of steady-state AC induction as well as waits in anticipation of AC fault, lightning, or other events that require over-voltage clamping. Users who have become familiar with reliable Dairyland decouplers will enjoy those same isolation and safety features, along with overcoming CIS measurement in the new PCRX.
PCRX Performance Results in Reliable Readings
Extensive testing of the PCRX was performed over a period of years and at a number of pipeline locations. Sites with standard decouplers that had user-identified delays in CIS waveform response were selected as testing locations for the PCRX. Most sites surveyed had employed the decouplers for mitigation of AC induction from nearby power lines. Cycling the rectifiers on that pipeline or segment, using typical on-off periods, Dairyland engineers obtained “as found” waveforms with the decouplers connected. Next, waveforms were obtained with all decouplers disconnected from the pipeline, for comparison. Disconnection was done on a temporary basis using safe practices and utilizing AC voltage measurements for verification. After disconnection, waveforms generally showed a large improvement in response time, as expected. Next, the PCRX was connected in place of the existing decouplers, and waveforms were again obtained, resulting in a response that typically would mimic that of a pipeline with no decouplers present. The waveforms below show a typical set of these three test conditions. Note how the PCRX response is essentially the same as with no decouplers present.
What They’re Saying:
Our early PCRX users and testers have already experienced the PCRX’s performance benefits and have seen it in action!
"Dairyland extensively tested various conditions on pipeline systems and eliminated the CIS issue."
"Dairyland’s new product reacts quickly with no perceived error in the pipe to soil readings."
"The PCRX provides a clean waveform while maintaining the required safety characteristics."
"I can’t wait to get my hands on Dairyland’s new decoupler and apply them to our system."