Fabric Sleeve Replacement
January 29, 2002
The most important item in changing a fabric sleeve is to note that the seam is either a lap or double hook joint. Arrows are printed on the sleeves to denote the direction in which the rotor should go past (sweep over) the joint.
The arrows assure that the seam is installed so that the waves of liquid sweep over the blunt edge of the seam, not against it. That is, sleeves should be installed so that the blunt edge of the lap joint is not facing into the waves of liquid that are pulsed by the rotor. While it is harder to visualize, the same effect is true with the double hook seams.
If the sleeve is installed the other way around, the wave of liquid created by the moving rotor paddle will hit an edge of fabric. This leads to early seam failure. This is true although there may be a film adhesive, which laps over the joint of fabric in a smooth manner.
It is important to take a few extra minutes when changing a sleeve. The seam should be straight with the main axis of the machine; the two hems should be uniform, without any pinches; there should be no dips or ripples in the fabric surface.
To properly install a new sleeve, first position it reasonably uniformly and clamp it tight. Next slightly tension the sleeve temporarily with the tensioning springs. This will make evident any non-uniformly tensioned areas. Loosen the sleeve clamp at one end and tap it so as to pull the fabric tight; then re-tighten the sleeve clamp.
The location of the seam of each sleeve should be noted. The options available include at the top, at the bottom, and next to an inspection door. Most commonly the seam is placed where it can be seen through the inspection door.
Safety tip: when inspecting sleeves with the machine in operation care must be taken. There is a natural tendency to poke a finger through a suspected hole. If this is done with the machine in operation, the rotor will surely sever the finger.
REMOVING AND RE-INSTALLING THE FABRIC SLEEVE ASSEMBLY
To remove the assembly that holds the fabric sleeves, first shut off the flow into the Fiber Filter and then turn off the machine. It will help to operate the backflush system before disassembly. Set the level of the rotor at an attitude, most generally the horizontal position, which will be convenient for removing the discharge head and sleeve assembly. An allen head wrench is used to loosen the setscrews that hold the inner race of the bearing that is mounted to the discharge head. Next the springs that tension the fabric should be removed, and the clamps (or bolts) that hold the discharge head to the main body should be released. This will allow the discharge housing to slip off the shaft of the rotor.
Vertical legs on its underside support the sleeve assembly. There is a pin welded at the top center of the inlet head, at the far end of the machine, down by the drive motor. This pin goes through hole in a plate of the sleeve assembly, to prevent it from rotating.
Look through the open end of the sleeve assembly to make sure the fabric is not dragged or pushed into the rotor. Do this during both disassembly and re-assembly operations.
The Fiber Filter has a collar with a setscrew that is located on one of the four tie rods of the sleeve assembly. It is used to hold the sleeve assembly reasonably tight during re-assembly operations. This will prevent the telescoping parts of the sleeve assembly from coming loose and allowing the fabric sleeves to sag. Upon tensioning the springs as a final re-assembly step, the telescoping piece will pull away from this collar. Normally this set collar is never moved during routine maintenance.
Following re-assembly of the Fiber Filter, check the fabric sleeves through the inspection panels. This should be done before putting power to the machine, as a loose sleeve will become entangled in the rotor.