What are the specifications for transformer oil sampling valves?

Transformer oil sampling valves should meet specific specifications to ensure accurate sampling and prevent contamination. Typically, they are designed to operate under high pressure and temperature, with materials resistant to oil degradation, such as stainless steel. The valve should have a minimum opening size of ¼ inch to allow for adequate flow, and it must feature a secure sealing mechanism to prevent leaks. Additionally, the valve should comply with industry standards, such as ASTM D923, for reliability and performance.