Eden has specialised in the supply and maintenance of electrical oils since 1985. In addition to our services for the supply of MIDEL 7131 and also on-site purification of MIDEL in service, we provide an oil to MIDEL conversion, or retrofill, service.
A correctly implemented MIDEL 7131 retrofill brings several benefits:-
- Enhanced fire safety.
- Higher environmental protection as MIDEL 7131 is readily and fully biodegradable.
- Increased moisture tolerance over mineral oil and silicones.
- Prolonging longevity of the transformer's solid insulation.
- Lower insurance premiums as a result of improved fire and environment safety.
It is important to note that changing a transformer to MIDEL 7131 is not a simple process of pumping the oil out of the transformer and MIDEL 7131 in. Steps have to be taken to minimise Oil in MIDEL contamination below 3.5% and also to heat and vacuum the MIDEL to improve air free penetration in to the windings.
Eden have worked with the manufacturers of MIDEL 7131 to tailor our retrofill service to meet their engineers and chemist’s requirements whilst deploying our dedicated MIDEL 7131 plant and hoses to ensure a correctly retrofilled transformer to the highest possible standard.
Key steps for a successful mineral oil to MIDEL 7131 retrofill:-
- To minimise risk of contamination from oil, use only plant, hoses and equipment that is dedicated to MIDEL 7131.
- Analyse existing mineral oil for Polychlorinated Biphenyls.
- Remove mineral oil from transformer in to suitable drums or IBCs.
- Remove transformer lid.
- Pump trapped oil from transformer dead spots.
- Allow transformer to drip down.
- Rinse down transformer internals with hot (60-80oC) dehydrated MIDEL 7131.
- Allow further time for transformer to drip down.
- Pump out rinsing MIDEL 7131 (label as contaminated with mineral oil).
- Fit cut lid gasket and refit lid.
- Fill transformer from the bottom at a maximum speed of 800 litres per hour using vacuum dehydration plant to remove air and moisture and to heat the new MIDEL 7131 to 60-80oC.
- Apply further cycles of vacuum dehydration to exceed BS EN 61203:1995.
- Fit a new desiccant breather.
- Fix MIDEL 7131 notice to transformer.
- Draw samples for analysis to confirm completed works meet BS EN 61203:1995.
- Ensure all waste products are removed by a licensed waste carrier to an Environment Agency permitted site.