ATTRACTIVE SOLUTION TO PERSISTENT LEAK AT PETROCHEMICAL PLANT

CHALLENGE

A petrochemical plant in France was experiencing ongoing issues with leakage of a highly corrosive substance through the mechanical seal on a CUP OH1 pump. In addition to being highly corrosive, the pumped liquid easily crystallised and led to quick deterioration of dynamic seals.

The leaks required monthly interventions to clean, repair or change damaged parts, including the employment of a specialised cleaning sub-contractor to comply with environmental standards.

The customer’s main aim was to reduce the frequency and cost of maintenance by suppressing all leak issues. They stipulated that the design solution should retain the same hydraulic performances and require no modifications of the current interfaces (baseplate general arrangement, suction and discharge flanges position).

SOLUTION

ClydeUnion Pumps replaced the mechanical seal with a magnetic drive back pull-out assembly. The advantage of magnetic drive technology compared to mechanical seal is that it contains the pumped liquid in a hermetic can with no need for a dynamic seal.

Our engineers undertook the integration of the magnetic drive assembly, selecting a size in accordance with the power to be transmitted. We also upgraded the motor from a foot design to a flange design and designed a new lantern and casing cover. Materials were specified to be compatible with the pumped liquid. The solution uses samarium-cobalt magnets to transmit heavy torques and resist high temperatures, alongside a zirconium oxide can to suppress eddy current losses generated by magnetic fields.

OUTCOMES

The new magnetic drive assembly for the pump has prevented further leakage, saving the costs of ongoing repair, maintenance and cleaning. With corrosion from leaking liquid eliminated, Mean Time Between Outages has significantly increased – leading to greater availability of the pump package.