Inflow Pressure Screen

• Installation & Commissioning

  1. Foundation 

  The machine belongs to rotary machinery, adopts reinforced concrete structure; the foundation is designed by civil engineering department; lay a good foundation and wait the foundation to reach the curing period, hang the screen to the foundation and pad the revising block and anchor bolts, grout the second time after preliminary horizontal correction, then accurate calibration after the cement firmed and fix the anchor bolts with equipment; the running stability of the screen is based on the levelness of the upper surface of the basket and big v-belt wheel, the above level should be corrected within 0.1mm/m.

   

  2. Lifting equipment and space

  In order to facilitate the installation and maintenance, lifting equipment should be equipped on the work site with lifting capacity of weight of the whole screen; above the pressure screen should stay the 2m height of the space to facilitate hanging out rotor body, basket and spindle, etc.

   

  3. Installation of pressure screen

  Hang the whole pressure screen from the supporting plate with lifting lugs on the base plate and lifting holes and place it on the foundation; when installation, keep level to make the screen body stable and make all anchor bolts uniformly stressed. Ensure that the machine is completely empty and tighten all bolts.

   

  4. Installation of motor

  Install vertically the motor onto base plate, which is arranged in the motor rail. Nest the v-belt wheel into motor shaft and make it at the same level with v-belt wheel of screen body; after the belt wheel installed, looking down from the top, the rotation of the motor should be clockwise.

   

  5. Installation of V belt and belt wheel

  ① Correctly install the belt wheel to the main shaft, correct the height of the motor belt wheel according to the height of belt wheel of the main shaft; after correction of two belt wheels, check the contact condition of the two belt wheels; turn two belt wheels half circle separately, ensure that the rotation of the belt wheel is correct; if any error, correct carefully.

  ② Install the V belt, adjust the center distance of the belt wheel to make the relax V belt tightened.

  ③ Ensure the rotating direction of main shaft is correct; look down from the top , the rotation of the rotor should be clockwise. Start the motor to adjust the tightness of the V belt; the key factor for effective operation of V belt driving device is the tightness of the V belt. Right tightness means no slip under the load of peak value and in the loading operation the relax side should be slightly arciform.

  ④ when the v-belt is stable after running some days, and then adjust the tightness of the belt.

   

  6. Connection of pipes

  Notice: Pressure screen body cannot be a bracket for connection pipe.

  ①The height of the inlet pulp pipe, outlet pulp pipe and tailing pipe should be generally about 1mm higher than pulp inlet to ensure the pressure screen is full of water to avoid interrupting pumping pulp; what’s more, reverse pressure is formed to help effectively adjust the pressure screen.

  ② Inlet pulp pipe should be equipped with valve, set a pressure sensor or pressure gauge at the inlet pulp pipe so as to control inlet pulp pressure in time and operate pressure difference to see whether the running is normal. The inlet pulp pipeline should be equipped with concentration control device so as to stabilize the inlet pulp consistency.

  ③ The outlet pulp pipe should be equipped with valve in order to control the flow rate and should be equipped with pressure sensor or pressure gauge at the same time; outlet pulp pipeline should has flow rate in order to know the throughput and make it stable. At least, in the accepted pulp chest install a flow rate to measure flow rate. At the end of the pipeline entering into accepted pulp chest, equip a control valve. Generally the accepted pulp need not be pumped; if inevitable, install a control valve.

  ④Open a hole at the bottom of the accepted pulp outlet pipe, arrange washing/emptying pipe with valve, connect with pure water and pollution discharge pipeline separately, closed at ordinary times, open the valve when shut down the machine to wash and discharge pollution.

  ⑤The outlet of the tailings pipe should be equipped with control valve and pressure sensor device or pressure gauge, arrange drain pipe and valve to the pipeline next to the screen so as to drain water when cleaning screen; install a flow rate control valve to the inlet of tailings chest.

  ⑥Install a control valve to the inlet of the dilution water.

  ⑦The connection pipe on the cap is used for emptying the air and possible light impurities. The cap should be opened when hang out the basket and check the inside, thus, use soft pipe to connect it to quick coupling; if continuously exhaust, discharge into tailings chest.

  ⑧The machine has been equipped with sealing water supplying pipeline which is used for mechanical sealing cooling and lubrication, including filter, pressure gauge, flow gauge, valve, etc. When installing, connect the pure water pipe from pure water pump with water inlet pipe of this system.

• Key points for operation

  1. Start up

  ① Check whether there is sundries in the machine before starting up. The rotor should rotate lightly when stir with hand. The clearance between blade and basket should meet with design dimension. Lubrication system has been added with lubrication grease. The driving system and the direction of rotating should meet with installation requirements.

  ② Open the sealing water valve and exhaust valve, close the inlet pulp pipe valve.

  ③ Open the dilution water valve, make the pressure screen full of water, adjust the opening degree of reject pipe valve

  ④ Switch on the motor, increase the flow rate of the stock slowly to prevent it clogging the basket; the consistency of the stock should be increased slowly to avoid exceeding the scope of the required consistency.

  ⑤ Adjust the quantity of the reject with valve to reach the requirement of discharge rate.

  ⑥Open the accepted pulp pipe valve slowly to avoid excessive quantity clogging the basket, adjust the inlet pulp valve and accepted pulp valve at the same time and observe the pressure gauge on the inlet pulp pipe and accepted pulp pipe until reach the required throughput.

  ⑦Open the reject valve to avoid blocking screen basket or reject pipe caused by possible big impurities or thickened pulp rejects.

  2. Running

  ①Keeping stable inlet consistency and flow rate is a vital precondition of running steadily.

  ② Inlet pulp pressure: generally 0.1-0.25Mpa

  ③Operating pressure difference: generally 0.01-0.06Mpa

  ④ Diluting water pressure should be 0.05-0.1Mpa higher than inlet pulp pressure.

  ⑤ The pressure of mechanical sealing water should be 0.05Mpa higher than inlet pulp pressure, with flow rate 2-5L/min, the water temperature discharged cannot exceed 60 centigrade.

  ⑥ If the exhaust pipe on the cap is not exhausting continuously, open the exhaust valve 3-4 times every day, two minutes every time, to clear away the gas accumulated in the top of basket to avoid interfering the normal operating.

  3. Cleaning basket

  ① If the basket is clogged, the electric current of the driving motor will increase and the pressure of the accepted pulp pipe will decrease. To handle the problem, close the accepted pulp valve and open the reject pipe valve, when the accepted pulp pipe pressure close to the inlet pulp pressure, indicating that the clog has been dredged. Open the accepted pulp valve slowly and put the discharge valve to its original position.

  ② If the pressure of accepted pulp pipe is still very low and inlet pulp pipe pressure very high, this indicates that the clog has not been removed. At this time, the pressure screen must stop running, open the upper cap, hang out the basket, wash the basket with high pressure water and examine wear degree of the basket.

  ③ When screening waste paper, gooey and fillers may clog the basket. If possible, use hot alkali liquor circulating flow in the screen to eliminate the clog, finally use pure water to circulate and rinse or hang out the basket periodically to wash with high pressure water.

  4. Stop running

  ① Stop to supply pulp and then pump into water.

  ② Let the water circulate in the screen, dilute the stock and clean the screen.

  ③ Close the accepted pulp valve, turn up diluting water valve and reject pipe valve, keep running until the residue pulp completely discharged.

  ④Close the motor, diluting water valve and reject pipe valve; open the exhaust valve at the same time.

  ⑤Close the sealing water valve.

• Maintenance

  1. The main shaft adopts lubricating grease, at the front end of engine base board set a device for adding oil, oil twice every week.
  2. Bearing of cap lifting device be oiled once a year.
  3. The tensity of the v-belt must be checked.
  4. Frequently check if the supply of mechanical sealing cooling water is normal or not, pull out the tubular filter net and clean regularly. When difference of two pressures before and after filter is greater than 0.1Mpa, the filter is clogged, need renew the filter.
  5. To avoid restarting difficultly, when shut down for a long time, the basket must be cleaned carefully.

• Dismantle main components

  1. Rotor body

  A. Loosen eight M20*50 fixed screws between the rotor body and support

  B. Screw two M16 lifting bolts into M16 holes on upper support ring (driving ring) and hang out rotor body assembly and then break down.

  2. Screen basket

  A. Dismantle the rotor body as indicated in step 1.

  B. Screw out 12 M12*20 inside hexagonal bolts and jack up basket slowly with two M16 jackscrew holes.

  C. Screw two M16 lifting bolts into screw holes on the screen face and hoist the basket. Install the basket as following steps after cleaning and check:

  a. Hang the basket into screen body, keep basket vertical, the bottom end surface of the screen basket must match correctly, contact surface must be clean without foreign matters.

  b. Align and clean the fixed screw hole on the top end face.

  c. Fix the basket crossing symmetrically with inner hexagon screws.

  3. Dismantle bearing pedestal

  When maintain or exchange bearing, must dismantle the axis, dismantle many accessories before dismantling axis. So according to above-mentioned methods, dismantle rotor body, basket, mechanical sealing box and big v-belt separately, and then dismantle bearing pedestal.

  Steps are as follows:

  A. Screw lifting bolts in screw holes on axis upper end.

  B. Hang lifting bolts to the hook on the hoisting equipment.

  C. Loosen and screw out fixed bolts linking driving support with pressure screen tank.

  D. Hang driving support as a whole out the screen tank, place it on a flat operating plate.

• Spare Parts

  1. Upper bearing of main shaft: 1 pair
  2. Below bearing of main shaft: 1 set
  3. Double end face mechanical sealing: 1 set
  4. Rotation axis lip-type sealing ring: 3 pieces
  5. Rotation axis lip-type sealing ring: 1 piece
  6. Driving belt: 4 pieces