Under normal use, if the pressure difference alarm of the pre-filter device alarms or the cumulative use exceeds 300 hours, the filter element should be replaced, and the double-barrel parallel pre-filter device can be stopped when replacing the filter.

Method of replacing filter element:
1, the replacement of the filter element of the single barrel pre-filter device
a. Close the oil inlet ball valve and open the upper end cover. (The upper end cover of the aluminum alloy type should be gently pry open from the side gap using a flat-mouth screwdriver);
b. Unscrew the plug wire of the sewage outlet to remove the dirty oil;
c. Loosen the fastening nut on the upper end of the filter element, hold the filter element tightly with oil-proof gloves, and remove the old filter element vertically upward;
d. Replace the new filter element, pad the upper sealing ring (the lower end has its own sealing pad), tighten the nut; f. Tighten the drain plug wire, cover the upper end cover (pay attention to the sealing ring), and tighten the bolts.

2, double bucket parallel pre-filter device filter element replacement
a. Close the oil inlet valve on the side where the filter element needs to be replaced, close the oil outlet valve a few minutes later, and then unscrew the end cover bolt to open the end cover;
b. Open the drain valve to completely drain the dirty oil to prevent the dirty oil from entering the clean oil chamber when replacing the filter element; c. Loosen the fastening nut on the upper end of the filter element, hold the filter element tightly with oil-proof gloves, and remove the old filter element vertically upward;
c. Replace the new filter element, pad the upper sealing ring (the lower end has its own sealing pad), tighten the nut;
d. Close the blowdown valve, cover the upper end cover (pay attention to the sealing ring), and tighten the bolts.
E. Open the oil inlet valve first, then open the exhaust valve, close the exhaust valve immediately when the exhaust valve is discharged, and then open the oil outlet valve; Then the other filter is operated in the same way.