Built-in filtering device

The utility model relates to the technical field of plate heat exchangers, in particular to a built-in filter device which comprises a cover plate, a first sealing gasket, a filter cartridge and a threaded column, the first sealing gasket is installed on the side face of the cover plate, the filter cartridge is arranged on the inner side of the first sealing gasket, and the threaded column is fixed to the filter cartridge. By arranging the fixing mechanism, when the device is used, the filter cartridge is plugged into the cooling liquid inflow channel, the second sealing gasket is tightly attached to the end plate of the plate heat exchanger, the knob is rotated, the knob drives the threaded rod to rotate, the threaded rod rotates to drive the piston plate to move, the air pressure on the left side of the piston plate is reduced, and the air pressure in the adsorption seat is reduced accordingly; the adsorption seats are firmly adsorbed on the end plate of the plate heat exchanger under the action of negative