FAQ

IMPELLER REMOVAL Removing the slurry pump impeller from a slurry pump for routine maintenance can usually be accomplished by securing the impeller against rotation and applying reverse torque to the shaft through a spanner or lever attached to the overhead crane. A few sharp hits with a hammer will generally loosen the plug threads if they have been properly coated with anti-seize and two release gaskets were used. As the wear life of TOWER wet end parts continues improving, the corresponding maintenance interval increases. Longer life and harsh duty conditions can result in the impeller to lock tighter on the shaft over time and make routine removal difficult. WARNING! Under no circumstances should heat be applied to the impeller! Air and moisture trapped in the internal cavity can expand and cause the impeller to explode! WARNING! Never operate the motor backwards to loosen or remove the impeller! This can result in mechanical damage and possible injury to personnel. Under the condition, when normal maintenance procedures could not remove the impeller, a technique using a drop bar and the impeller inertia can be used to break the threads loose lightly. The end of a weighted bar is lifted and allowed to drop, turning the impeller in the normal operational direction. When the end of the bar hits a stop plate on the floor, the shock of the sudden stop combined with the inertia of the impeller will generally loosen the plug threads. Mild steel should be used. Fabricate a plate that bolts to the coupling half or sheave on the pump shaft. This can be made to attach in the gap between the coupling sections. Multiple bolt patterns will accommodate different pumps in the facility. Using a length of beam, plate or steel tubing, add the longest practical arm that will safely rotate from near vertical to the floor or other solid stop point. On the end of the arm add a weight which doubles as an impact face. For most slurry pumps, use about 180kg or a block about 600 x 255 x 150mm. A ring or other release point is installed on top. Be certain that all parts are welded adequately as the impact forces can be severe. If plate is used for the arm, it should have a brace or gussets to prevent bending. Use proper safety practices and keep all persons away here. Place a steel plate on the impact area of the floor to avoid any other damage. Verify that the arm will rotate the impeller in the correct direction. Raise the arm with the overhead crane to a near vertical position and release it. Allow the arm to drop and hit the plate. It may take multiple hits. Once the slurry pump impeller is free to turn on the threads, install the impeller lifting device and complete the removal procedure.

How to Starting Up Slurry Pumps? The initial starting sequence detailed is intended to bring the system up to operating condition safely with minimal effort. Following those instructions and this simple checklist will have the pumps on line quickly: 1. Verify that all guards, piping, and instrument connections are properly installed and tightened. 2. Open the suction valve completely and verify there are no obstructions in the suction flow. 3. Fill the sump and system as full as possible. The sump should be at operating level but must be at least above the level of minimum suction head (NPSHR) required by the slurry pump. a. If mechanical seals are used, the pump cavity must have fluid at least above the top of the suction line. If equipped, turn on flush or cooling supply valves. b. For stuffing boxes, turn on the gland water supply. Verify flow and pressure are in accordance with the Excellence Maintenance Manual and water is dripping from the gland. c. Never start or run the pump with zero flow! d. Turn on any cooling water or fans for other equipment. 4. Close the discharge valve. a. For vertical discharge pumps or systems with air in the discharge piping, open the discharge valve an inch or two (25 – 50 mm) before starting. This will let the air bleed out as the pump comes up to speed. b. Do not open the valve past 25% or the pump could rotate in reverse during backflow. 5. Check that all personnel and loose items are clear of the pump and rotating elements. 6. Jog the motor to verify that pump rotation is correct. 7. Start the motor. The pump should reach operating speed in just a few seconds. 8. As the pump reaches operating speed, fully open the discharge valve. Do not allow the pump to operate with the valve closed as there is a danger of steam generation and explosion! 9. Inspect the pump and drive components for any leaks or unusual vibrations. After the pumps have been operating and the system is full, the pumps can be stopped by closing the discharge valve as the pump is shut off. This will reduce backflow potential in the system. Never close the suction valve while the pump is running or coasting down, as this could create cavitations. Starting the slurry pumps during normal slurry operation may be done in this same manner

1 The rubber suction seal ring. This side should touch the throatbush. The fillister should match the bulge of the throatbush. 2 The bulge of the throatbush has its processing exactness limitation. Sometimes, it could not match the seal ring very closely, which may lead the leakage. Under this situation, we use another thin rubber piece. 3 Get the round ring from the thin rubber piece.Make the rubber circle ring match the fillister of the suction seal ring well, the frame and the dimensions.Put the circle ring into the fillister of the suction seal ring and put the complete one on the throatbush. 4 We are sure the leakage is just due to the suction seal ring. Therefore, we offer the solutions of the problem this way

SLURRY PUMP IMPELLER ADJUSTMENT 1. Initial Adjustment With a Gland Seal assembly fitted, both Rubber and Metal Lined Slurry Pumps should be adjusted to operate with the Impeller having minimum axial clearance with the front casing liner (Throatbush or Cover Plate Liner). This is most important with High Efficiency Impellers. Adjustment of Impeller front-end clearance is carried out as follows: (a) Rotate the Shaft clockwise (as viewed from the drive end) by hand, and move the Bearing Assembly forward (towards the pump intake) by adjusting the rear nut on the ADJUSTING SCREW until the Impeller rubs on the front Liner. (b) Unscrew the rear nut by one sixth of a turn, and move the Bearing Assembly back by adjustment of the front nut on the Adjusting Screw until the plug on the Bearing Assembly contacts the rear nut. Fully tighten the front nut to secure the Bearing Assembly in position. (c) Ensure that the Shaft can now rotate freely without contact of the Impeller with the front Liner. If contact occurs, repeat step (b). NOTE: After each Impeller adjustment is completed, the BEARING HOUSING CLAMP BOLTS must be tightened to torque values indicated in (Ref.2), below. If a torque wrench, or equivalent device is not available, bolts should be tightened as Ref.3. With a Centrifugal Seal or Super Seal assembly fitted, the pump should be adjusted to operate with the Impeller having approximately equal axial clearance with the front and rear casing liners. If leakage occurs from the Centrifugal or Super Seal during slurry pump operation, the Impeller should be adjusted rearwards to minimize axial clearance between the Impeller and rear casing liner. If seal leakage persists after Impeller adjustment, this indicates that the intake pressure is excessive for the Impeller fitted. Leakage may be prevented by fitting of an alternative Impeller having improved intake pressure sealing characteristics. This may require fitting of a differential Impeller. (2) Periodic Adjustment Periodic adjustment of Impeller clearance over its operating life is an important factor in maximizing wear life of both Impeller and front Liner. Extensive field experience has shown that an increase in wear life of up to 50 percent can be achieved by regular Impeller adjustment, compared with pumps not subject to initial or ongoing adjustment. Regular Impeller adjustment has shown an increase in wear life of typically 20 percent compared with pumps subjected only to initial adjustment. The recommended procedure for periodic Impeller adjustment is as follows: (a) At initial pump assembly, adjust Impeller to “just clear” the Throatbush or front Liner, as described in (1). (b) After 50 to 100 hours of slurry pump operation, re-adjust Impeller front-end clearance. (c) Re-adjust Impeller front-end clearance a further two or three times at regular intervals over its wear life. This may coincide with regular pump maintenance intervals, typically 500 hours. NOTE: After each Impeller adjustment is completed, the BEARING HOUSING CLAMP BOLTS must be tightened to torque values indicated in (Ref.2), below. If a torque wrench, or equivalent device is not available, bolts should be tightened as Ref.3 TIGHTENING TORQUE (Ref.2) For CLAMP BOLTS on the bearing housing Frame Size Minimum Torque(N m) A & B 10 C & D 45 E & F 185 G 325

Our heavy-duty slurry pumps and parts have been reengineered to remove known industry complaints such as flow instability, cavitation, and seal failure. Our slurry pumps and spares are built to last and withstand the varying materials they are processing and the environments in which they operate. The options materials are abrasive rubber, high white iron chrome, and ceramic. These materials are used to deliver solutions that are suitable for the harshest pumping environments. For applications like Dredging, our larger capacity dredging pumps are well suited to the dredging operations in many fields. Where the dredge is used to mine sands and silts along with large volumes of water and pump to a fixed plant for treatment and separation.