SIIC team introduces you about operation of bag filter house/filter vessels: daily operation-opening top cover-sequence of opening lid (top cover)-filter bag replacement-discharge residual liquid.
1. Daily operation: when liquid entry pressure is stable, filtration performance has close relationship with pressure difference of filter bags. If the pressure difference is too large, the filter bag holes have been blocked and the filtration rate has decreased. Therefore, the pressure difference should be checked regularly after the filter work, and the filter bag changing time is determined by the pressure difference between the pressure displayed by the front and rear pressure gauges. When the pressure difference reaches 0.05Mpa-0.1Mpa, the filter bag should be replaced in time so as to avoid filter bag rupture or support basket damage and influence the filtration effect caused by pressure difference.
2. Opening top cover correctly: do not open the top cover when the filter is under pressure, otherwise the remaining liquid may be ejected, resulting in liquid loss or personnel injury.
3. Correct sequence of opening lid (top cover): (1) Close the inlet valve. When there is pressing filtration at outlet, please close inlet valve. (2) Open the exhaust valve. To prevent damage and pollution to people and surrounding environment, the staff can not face the exhaust valve. (3) Check the pressure gauge, confirm the internal pressure is 0, and same time the filter should be separated from the piping system. (4) When filter is with discharge valve, please confirm the discharge valve is connecting to recycle position. Open the drain valve, after left liquid inside of bag filter drain away, close drain valve please. This discharge work can be completed in pressurized manner. (5) Unscrew the hanging cap of the upper cover and lift the top cover.
4. Changing the filter bag: (1) the filter bag is made of fine fiber, and the surface will not be wetted by water. So before the installation, you must put the filter bag into the pre wetting liquid which matches the filtration liquid for a few minutes, and make bag fully wetted. (2) Open the top cover of the filter correctly. (3) Put the top cover firmly and take old filter bag out of house carefully. (4) Put new filter bag into house. Refer to the installation process for the rest works.
5. Using pressure to discharge residual liquid: when filtering the high viscosity liquid, to improve discharging speed of remaining liquid and shorten waiting time, you can input compressed air through exhaust valve. Please note that the compressed air pressure cannot be higher than the working pressure of the filter. The exact steps are as follows: (1) close the input valve. (2) Open the intake valve, the gas goes into the filter, increase the pressure and make remaining liquid drain away. (3) Check the outlet pressure gauge, and confirm the pressure and compressed air pressure are equal. (4) Make sure that the outlet is free of liquid and closes the intake valve. (5) Open the exhaust valve slowly, residual liquid comes out of exhaust valve, it must be led to the safe position or filter suction port. (6) After the compressed air is exhausted, please close the exhaust valve. There should be no pressure inside the filter, now you can open the top cover.