hi, could u tell me the joints or fits in which the buttrefly valve is operating without any leakage.?

Question

the valve which is in air tight condition and the spool can be operated from external source.

Answer 1

If you can dip the whole assembly into a bucket of water, pressurize it with the valve closed, then dip it in the water to see if any bubbles come up. If you cannot dip it, try pressurize it then use a sponge to put soap water around it to see if anything bubbles out.

If you cannot pressurize it then there is no way to leak test it.