Urban heat pipe welding butterfly pneumatic valve

urban heat pipe welding when butterfly pneumatic valve:
( ） Pneumatic valve plate of the shaft should be installed in a horizontal direction, axis and the maximum horizontal plane Angle should not be greater than degrees, it is forbidden to vertical installation.
　　（ ） When installed on the riser, pneumatic valve to the closed before welding plate above into deep mm above the water.
　　（ ） After the completion of the welding, or totally open to prove that the pneumatic valve can work normally.