Drainage according to the needs of the site and space characteristics, can have a water seal drainage device, can also be with a sealed valve drainage device, can also be a combination of water seal and sealing valve drainage device. Water seal drainer is to rely on the principle of the water seal pressure generated by the suppression of the gas, the gas and water in the pipes and drainage device, the gas in the above, the water below, when more than the height of the drain water, water is flowing from the port of discharge, and gas water seal seal, return piping, so as to achieve the goal of drainage not exhaust. This drain is relatively simple. But if the design is not reasonable, will cause the use invalidity. Sealing valve drainage device, usually choose float ball valve or float ball connecting rod valve, this according to the technical ability of each enterprise development, my company is used is floating ball connecting rod valve, after many users on the site use effect is better.