JM742X diaphragm type bottom sludge discharge valve consists of a main valve, a 4/2-way directional valve and a valve disc. When the 4/2-way directional valve is in one state, water enters the cavity of the main valve, and the upper chamber is vented to the atmosphere. The diaphragm rises with the pressure of the water to open the main valve, stirring up the sediments at the bottom of the tank. When the 4/2-way directional valve is in the other state, the upper chamber of the main valve is fille