Buchholz Relay Angle

If the pipe line is kept horizontal, any gas formed out of oil decomposition would not escape to the Buch Holz Relay but would settle at the top plane of the pipe only. Thus, no gas collection in the relay and the relay would not operate. The very purpose of providing the realy is lost. Isn't it?

On the other hand, if you keep the pipe sloped/inclined, because of the slope, the gases formed out of decomposition, will continue to travel upwards into the relay and as the relay is kept horizontal, the gases will accumulate in the top part of the relay thus causing the floats to tilt & thus activate the contacts.

Why only 2 to 7 degrees slope? I am not very sure. May be convention. The first installer kept at 2 to 7 degrees on a trial basis, it worked and everybody emulated him.

Not the angle for buchholz relay. The pipes connecting to the reservoir shall be in angle slope upwards to ensure the gas flow without any hydodynamic restriction. The relay is fixed in this pipe. Even I dont know why it is 2 to 7 degree.