Operation And Maintenance Of AF Vertical Forth Pump

AF series vertical forth pumps are widely used in metallurgical, mining, coal, chemical, and other industries. This series of pumps effectively eliminates the foam in the slurry during operation; When the incoming material is insufficient, it still keeps working. This pump is especially suitable for various flotation processes and can be used to transport 73% high-concentration slurry, which is an ideal product for conveying foam slurry.

AF Vertical Forth Pump Structure Instruction

AF series forth pump has a simple structure, which is convenient to install with a high degree of generalization. Please refer to the structural diagram for details.

  1. Transmission part: The transmission part of this type of pump is similar to other series slurry pumps. When choosing the pumps, we can select direct transmission or belt transmission type pumps according to the user’s requirement
  2. The material box adopts a steel structure, with a tangential inlet and overflow box. The overflow box will send excess incoming materials back to the material pool; the tangential inlet makes the slurry enter the pump quickly, eliminating part of the foam.
  3. Pump head: The pump head structure is the same as the other series slurry pump with a double pump casing structure. The pump body, pump cover, front guard plate, and other slurry pumps with the same caliber as the other series are universal. According to the different conveying media, the material of the flow passage component can be metal, rubber, or other non-metallic materials. For metal materials, the pump body, pump cover, sheath, and front guard plate are common to other series slurry pumps with the same caliber; For rubber or other non-metallic materials, the front and rear sheaths are universal for slurry pumps with the same caliber as TNH and R series.
AF Vertical Forth Pump Structure (1)
AF Vertical Forth Pump Structure (1)


When assembling the bearing body, the preheating temperature of the inner ring of the bearing is not allowed to exceed 120 ℃; The inner ring of the bearing must be tightly against the shoulder or gear sleeve.

It is recommended to use lithium lubricating grease  2 # or 3 # for bearing lubrication.

  • Assembly of bearing components, tank, and pump head parts.

Put the bearing assembly on the top of the material box and fix it with bolts. Then, install the sealing gasket of the material box and fix the pump body on the material box with bolts. Install the protective plate, impeller, sheath, and pump cover in sequence according to the structural diagram. Secure the pump cover to the pump body with bolts. Tighten the connecting bolts between the pump body and the material box evenly. Check if the impeller rotates smoothly and if there is friction. If there is friction, add a pad on the bolt connection between the bearing body and the top surface of the material box for adjustment, and at last tight all fasteners.


How does the AF vertical forth pump operate?

1. Starting

Before starting, check the pump generator set according to the following steps.

(1) The pump should be installed on a solid foundation and must tighten all foundation bolts to withstand the total weight of the pump and eliminate vibration when it is working.

(2) Support the pipeline separately and concentric with the pump flange.

(3) Rotate the shaft by hand in the pump rotation direction. When the shaft drives the impeller to move, there should be no friction, or there will need to adjust the impeller clearance.

(4) Cut the connection between the pump and motor, and check the rotation direction of the motor to ensure that the pump rotates in the direction indicated by the arrow on the pump body. Note that the pump is not allowed to turn around in the opposite direction, or the impeller thread will trip and cause damage to the pump.

(5) During belt transmission, there will need a certain pre-tightening force to the triangular belt; The pump shaft should be parallel to the motor shaft so that the direction of the triangular belt will be consistent with the end face of the pulley to avoid severe vibration and wear. During direct transmission: The pump shaft and motor shaft should be accurately aligned, or it may cause vibration or damage to the bearings.

 2. Running

For AF vertical forth pumps that work well, we should check the operation of bearing components and add lubricating grease regularly. If the bearings of the initial running pump heat up, we should stop the pump and cool down the pump before running again. If the bearings still generate severe heat and the temperature continues to rise, it is necessary to disassemble and inspect the bearing components to investigate the cause. Generally, the heating of bearings is often caused by excessive lubricating grease or impurities in the grease. The amount of bearing grease is appropriate and clean.

The performance of the pump decreases as the wear gap between the impeller and the protective plate increases; If it is found that the pump efficiency decreases or the flow head is much lower than the parameters, the impeller should be adjusted upwards in time to keep a certain reasonable clearance, so that the pump will operate in the high efficiency zone; If the pump is severely worn and cannot meet the system requirements, replace the vulnerable parts.

The pump shall not operate under low or zero flow conditions for a long time, nor shall it operate under any circumstances that may cause vaporization of the pumped liquid. If liquid vaporization occurs, fix a baffle in the material box to change the direction of water flow and eliminate the entry of steam into the pump chamber.

3. Stop

Before stopping the pump, try to pump clean water as much as possible to clean the slurry flowing through the pump, and then close the incoming gate valve, and pump outlet valve in sequence.

AF Vertical Forth Pump
AF Vertical Forth Pump

AF Vertical Forth Pumps Maintenance

In order to ensure the regular operation of the pump, it is necessary to pay attention to daily maintenance as the following aspects:

  1. Adjustment of the impeller

In order to ensure the efficient operation of the pump, it is necessary to adjust the clearance between the impeller and the liner plate in time.

The steps are as follows: stop the pump and loosen the bolts that fasten the bearing body; Add adjusting shims between the connection between the bearing body and the material box, so that the bearing components will move upwards. At the same time, rotate the shaft in the direction of pump operation until the impeller by hand and the liner plate slightly rub against each other; Tighten the fastening bolts and recheck whether the impeller rotates well. The clearance between the impeller and the liner plate is 0.5-1mm for metal-lined pumps. In a rubber-lined pump, move the bearing component downwards to make the impeller connect with the sheath. Based on the total movement of the bearing component, take this half as the gap between the impeller and the sheath.

  1. Bearing lubrication

When assembling the shaft, add an appropriate amount of lubricating grease. During operation, we can add lubricating grease regularly, but adding too much lubricating grease will cause the bearings to heat up. The amount and cycle of lubricating grease injection vary with different working conditions, so we should accumulate experience in use.

The standby pump remains stationary for a long time.

It is recommended to manually rotate the bearing by 1/4 turn every week to withstand static load and external vibration.

Possible faults and solutions

Fault 1: Excessive shaft power


  • Friction inside the pump
  • Bearing damage
  • Drive belt too tight
  • Excessive pump flow
  • The motor shaft is not aligned or parallel to the pump shaft


  • Eliminating friction
  • Replacing bearings
  • Adjusting the belt center distance
  • Adjusting the operating conditions of the pump
  • Adjusting the motor shaft and pump shaft
Fault 2: High Bearing temperature


  • Excessive or insufficient bearing grease
  • There are impurities in the lubricating grease
  • Bearing damage


  • Adding the appropriate amount of lubricating grease
  • Replace the lubricating grease
  • Replacing bearings
Fault 3: Short bearing life


  • The motor shaft and pump shaft are not aligned or parallel. Axis bending.
  • There is friction or impeller imbalance inside the pump, and foreign objects or lubricating grease amount in the pump is an improper assembly of bearings.


  • Adjust the motor shaft and pump shaft.
  • Replace the shaft
  • Eliminate friction and replace the impeller to clean the shaft.
  • Replace or reassemble bearings.
Fault 4: Pump vibration, Noisy


  • Bearing damage
  • Impeller imbalance of the air intake in the pump block
  • uneven flow rate, pump evacuation


  • Replace with a new bearing
  • Replace the impeller with a new one
  • Eliminate air intake and clear blockages
  • Improve the pump feeding situation

JXSC Mine Machinery Factory provides all types of mining machines and various pumps, and all machines accept customization. If there are any machines you need, warm welcome to inquire. Contact us online to get the factory price!

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