Principle and Maintenance of Automatic Backwash Filter

JX Filtration January 19, 2024 Automatic Backwash Filter

Principle of Backwash Filter:

The filter consists of two or more filter chambers, with one or more filters in operation and one in standby. When the working filter element becomes blocked, causing an increase in pressure difference, the system automatically switches to the standby filter. It uses compressed air in reverse to initiate backwashing, and then refills with clean oil for standby. The filter chamber contains a set of upright tubular filter elements that are not easily damaged and can generally be used for an extended period. During backwashing, compressed air is blown from the inside to the outside to remove impurities.
Automatic backwashing control and protection devices. The two-position three-way valve can be electrically or manually switched between two positions to control the switching of the filter. The backwashing valve, also electrically or manually controlled, regulates the opening and closing of the oil discharge valve. The pressure difference relay converts the pressure difference signal into an electrical signal, controlling the automatic backwashing of the filter. The pressure balance relay converts the pressure signal into an electrical signal, providing self-locking for the filter backwashing.

Maintenance of Self-Cleaning Filter during Normal Use:

During normal use of the filter, the following inspection and maintenance items are required:

Regularly check for leaks in all pipe joints.
Check and clean the air filter (in the compressed air unit) monthly.
Check the oil level of the lubricator (in the compressed air unit) monthly and maintain it at a high level.
When disassembling the entire filter is necessary, use preventive maintenance to replace the new sealing gasket.
Check for leaks in the oil discharge valve monthly. To do this, open the vent cock on the oil storage tank after emptying the recovery device. If oil continues to leak after the filter is in operation, it indicates a leak in the discharge valve.
Check the pressure difference indicator of the recovery device weekly. If it shows red, it indicates that the filter is dirty. If 90% of it is red, the filter element must be replaced immediately. Generally, it must be cleaned or replaced at most every four months.
Perform a manual backwash before each use and weekly to check if the backwashing process is normal.
For a new filter put into use, check the backwash filter element after 500 backwash cycles, and then perform a check every 5000 backwash cycles.