United valve consists of a valve core and valve seat, the valve seat connected to the upper 4-5 inlet pipe, the lower connected to a outlet pipe. The valve core is a cylinder with holes drilled in the bottom and the middle of the cylinder and communicating with each other in the vertical direction. The valve core and the valve seat are connected with a dynamic fit. When the boiler blowdown, through the hand wheel to rotate the moving core, when the central hole in the valve core and the inlet of a water inlet relative to the inlet pipe connected to the circulation loop of water through the valve seat, spool From the lower part of the valve seat outlet, stop when the sewage. Just turn the handwheel so that the hole in the middle of the valve core is staggered with the hole on the seat. When the shut-down water, the valve will be combined with the exit of the valve, lift the spool, five-point connection of the five loops can be discharged through the valve seat at the same time, shorten the water discharge time.