Ravebo were requested to mobilize an engineering team to Power generation plant operated by one of The Netherlands Major generating companies. The valve in question was a Nakakita Spring return emergency valve. During testing it was observed That the valve was not reacting when the hydraulic oil pressure was deactivated and hence was not closing according to the Recommendations.
With the added pressure of Japan beginning to wind down in preparation for their National Golden Week celebrations Mitsubishi who commissioned the plant was able to obtain the urgently required spares from another plant. Once the spares had arrived Ravebo mobilized 2 engineers to attend the plant and proceeded to disassemble the valve and the actuator. Once stripped the valve internals such as inner valve, shaft disc etc. were checked and were found to be within the permitted tolerance levels. After further examination it became conclusive that the problems were with the consumable spare parts.
All the O-Rings, bushes and gland packing’s were replaced and the valve was then reassembled.
Once the valve and actuator was reassembled, a final test in the presence of the power plant the work was deemed a success and enabled the power plant
To return to full capacity.