The P&B RGV consists of an oil and gas-proof aluminium vessel with two inspection ports fitted with glass windows, one graduated – see figure 1.
The gases accumulated in the Buchholz relay can be transferred to the RGV for easier measurement on the graduated scale and evaluated by drawing these off at ground level.

Technical details

The RGV is mounted vertically using two M10 tapped holes at the rear of the unit.

The pipework should be configured as shown in figure 2. Copper tube 6mm (1/4″) o/d should be used to connect between the Buchholz
and the RGV using the fittings kit (available separately: RAG-04928).

Both ballvalves upon the Buchholz should be open. The ‘Test’ and ‘Gas’ ballvalves should also be turned to the open position. Open the Sample ballvalve upon the RGV until all the air within the vessel and pipework is extracted and then, when the RGV is full of oil, close the ‘Sample’ ballvalve followed by the ‘Test’ and ‘Gas’ ballvalves. The ballvalves upon the Buchholz remain open. Check pipework for leaks etc. in accordance with standard site commissioning procedures.

Open the ‘Gas’ valve upon the RGV followed by the ‘Drain’ valve (into a suitable container), the gas/air collected in the Buchholz will syphon into the RGV.

Close the ‘Drain’ valve when the gas has transferred. The volume can be calibrated against the window scale of the RGV. The gas/air can be sampled or expelled using the ‘Sample’ valve into a suitable container. Once the unit is again full of oil, close the ‘Sample’ then ‘Gas’ valves upon the RGV.

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