MERLIN Nitrogen Sleeve Monitor
High and medium pressure pipelines passing under main roads, rivers or centres of population may require additional protection against corrosion. One of the methods used is to encapsulate the pipeline with a metal "sleeve" filled with Nitrogen, an inert gas that prevents the external pipe wall surface from corroding. The nitrogen gas is typically pressurised to 1bar (100kPa). For this method to be effective, the pressure of the nitrogen in the sleeve has to be maintained. This means operators must check the pressure in the sleeve periodically to make sure that it is not leaking. If the pressure has dropped to an unacceptable level, the sleeve must be refilled with nitrogen, which can be a very labour-intensive activity since the gas containers are heavy and bulky to carry and the fill points are often difficult to access.Now the pipeline operator can check that the sleeve is maintaining the required pressure without undertaking a site visit. Even if the gas is leaking, the operator can monitor the pressure drop and schedule maintenance accordingly. In this way unnecessary site visits can be avoided. The MERLIN Nitrogen Sleeve Monitor measures the sleeve pressure automatically, checks that it is within specification and reports immediately if an alarm threshold is exceeded. Like MERLIN CP monitors, it communicates (via either an internal or external antenna) using the GSM network and is installed in the same way, simply requiring a mobile phone.Once installed, pressure data is reported automatically and viewed, alongside data from cathodic protection monitors, in Abriox's iCPSM software. iCPSM provides access from any Internet-enabled PC to a password-protected database, unique to each customer. Users can configure and control MERLIN monitors, view data in graphical and numerical formats or export data for further analysis and archiving. An alternative user interface is the PC-based CPSM3 software.