Shutdown Operation Before Installing the Pressure Screen Basket
Before installing the pressure screen basket, ensure that the pressure screen equipment is completely shut down, the main power supply is disconnected, and lockout and tagout procedures are followed to prevent accidental startup during screen drum replacement. If the screen basket operates under pressure or contains pulp slurry, ensure the system pressure is fully released and all pulp inside the screening chamber is emptied before installation. Remove obstacles and ensure sufficient working space and lighting conditions. A clean environment improves installation accuracy and reduces safety risks. Operators should wear protective helmets, safety goggles, anti-cut gloves, and safety shoes during screen drum installation to avoid injuries.
Preparations Before Installing the Pressure Screen Basket
- Check the new screen basket: Verify that the new model, dimensions, and slot or hole design fully match the original basket and equipment requirements.
- Inspect the Appearance: Carefully inspect the appearance of the screen basket and confirm that there is no transportation damage (such as dents, deformations, clogged or damaged sieve seams/holes)
- Check Installation Accessories: Check whether all accessories (such as sealing rings, locating pins, fasteners) are complete and intact.
- Clean the installation area: Thoroughly clean the chamber or base where the pressure screen basket will be installed. Remove all residual pulp, fibers, impurities, old sealing ring fragments, etc. Pay special attention to the cleanliness of the sealing surface, as any small particles may cause leakage.
Disassembly of Old Pressure Screen Basket
Remove the bolts, covers, or clamps that secure the screen basket in order. Pay attention to recording the disassembly sequence and position (can be photographed). Carefully remove the old screen basket to avoid bumping into the interior of the chamber or damaging other components. Note that the old screen drum may be heavy, use a suitable lifting method. Thoroughly clean the exposed sealing and positioning surfaces of the cavity after disassembly.
Installation of New Pressure Screen Basket
- Lubricate seals: Apply a layer of recommended or compatible lubricating grease (usually food grade silicone grease or special gas dragon lubricating grease, avoiding the use of petroleum based grease, especially in the food or paper industry) evenly on the new sealing ring (ring, gasket). Facilitates the installation of the pressure screen basket, prevents the sealing ring from twisting or cutting, and extends its lifespan.
- Place the seal: Place the lubricated seal correctly in the sealing groove of the cavity or screen basket, ensuring that it is fully seated, without distortion or folding. Lifting and alignment: Use appropriate lifting tools (if necessary) to carefully lift the new screen basket and smoothly move it into the installation chamber.
The Most Critical Part of Installing Pressure Screen Basket
- Accurate alignment: Ensure that the positioning marks on the screen basket (if any) are aligned with the marks on the cavity. If there are locating pins or keyways, they must be perfectly aligned. Avoid collision: During the insertion process, it is absolutely necessary to avoid collision or friction between the screen basket (especially the sieve gap/sieve hole area) and the cavity wall or other components.
- Positioning inspection: Ensure that the screen drum is completely lowered to the bottom and in contact with the positioning surface. Gently tap with your hand or rubber hammer to confirm if it is fully in place (do not use a metal hammer to strike vigorously).
Fastener Installation and Torque Control
Install the cover, clamp, or fastening bolt and tighten the bolt in diagonal order, which is the most critical step! Do not tighten individual bolts at once. Tighten all bolts gradually and evenly to the specified torque value in 2-3 steps according to the manufacturer’s specified sequence (usually diagonal sequence). It is crucial to use a torque wrench! Uneven fastening can cause deformation of the pressure screen basket, seal failure, or uneven operation. Ensure that all fasteners are installed in place and subjected to uniform force.
Post Installation Inspection of Pressure Screen Basket
- Visually inspect whether the position of the pressure screen basket in the cavity is centered and upright.
- Check if all fasteners have been tightened to the correct torque.
- Check if the seals are correctly installed in place, without extrusion or distortion.