1、 Function and type of secondary filter screen
?? Secondary filter screen It is one of the main equipment in the rubber ball cleaning device. Its function is to filter the cooling water, remove the impurities that may block the heat exchange tube of the condenser, and ensure the normal operation, recovery and operation of the sponge rubber ball. Especially in the open cooling water system with many impurities in the water and greatly affected by seasons, the secondary filter screen plays an important role. The secondary filter screen can be divided into electric pressure recoil type, switching type, external rotation type, etc.
3、 Working principle of various secondary filters
1. TG type fully sealed electric pressure recoil type secondary filter screen
Working principle of TG type secondary filter screen: cooling water flows from the outside of the mesh core to the inner of the mesh core, and the impurities and dirt are attached to the outer wall of the mesh core. When cleaning, the electric drive mechanism drives the mesh core to rotate, and the sewage gate opens. The debris accumulated on the mesh core is carried by the backwash water and discharged from the sewage pipe orifice. It has the performance of cleaning the mesh core without stopping the machine. The amount of discharge water is less than 10% of the circulating water.
2. Fe type switching backwash secondary filter screen
?? Fe type secondary filter screen adopts four mesh cores. The cooling water flows from the core to the core, and the impurities and dirt accumulate in the core. When the pressure difference between the inner and outer parts of the mesh core is greater than a certain value, the valve plate is operated one by one to turn 90 degrees to cut off the cooling water entering the mesh core, and the drain outlet is opened. At this time, the cooling water outside the (single) mesh core flows into the mesh core, and the impurities and dirt are discharged from the drain outlet, After cleaning the mesh core in turn, it will return to normal operation.
3. We series external rotary secondary filter screen
The influent water of we series external rotary secondary filter screen flows from the outside of the mesh core to the inner of the mesh core, and the impurities in the circulating cooling water block and accumulate around the outside of the mesh core. When the internal and external pressure difference of the mesh core reaches a certain value, the blowdown valve can be opened and the electric butterfly valve can be turned from the full open position to the guide position (the electric butterfly valve is in the full open state when the normal operation of the electric butterfly valve), so as to make the circulating cooling water rapidly rotate and flow around the outer circumference of the mesh core, so as to flush the foreign matters accumulated in the outer circumference of the mesh core into the upper blowdown pipe for discharge. When the valve is fully flushed, it will be closed.