How can I tell if the transformer pressure relief valve is working properly?

I. Appearance and sealing inspection Visual inspection of the appearance of the pressure relief valve shell to see whether there is deformation, cracks, damage or corrosion, whether the injection port is blocked by foreign objects (such as oil, dust, metal shavings, etc.), if there is a blockage may lead to the valve can not be opened or closed properly. Check whether the sealing rubber gasket is aging, broken...