Croos Pump (Shanghai) Co., Ltd.

Techincal Help

PIPELINE CONNECTION
  • The water pipe should have its own supports in order to avoid all the weights depressing on the pump.
  • The pump line should be connected to the discharge nozzle by means of a flaring pipe with taper 1:7.
  • The average flowing velocity of water in the pipe is recommended not to exceed 2-3 m./s.
  • As for the suction pipe, the follows must be considered: the pipe must be as short as possible so as to reduce the resistance possible.The pipe must be bent according to prevailing regulation. It is not permitted to have too small bending curvature in order to avoid producing excessive losses.The connections of the pipes must be tight to prevent air from entering into the pipes.
  • When the pump position is higher than the water level, a foot valve should be installed at the bottom of the suction pipe or priming by a vacuum pump.
  • A gate valve and a non-return valve are installed between the discharge pipe and the pump. The inner diameters of the valves must not be smaller than the discharge pipe. The non-return valve is located on fro-side of the gate valve.
OPERATION
  • Inspecting the dates in the nameplate such as capacity, head, speed, and they must be accordance with the requirement.
  • The couplings shall be operating smoothly when rotating the pump by hands.
  • The starting task is to inspect whether the rotation direction of the motor corresponds to the requirement of the pump.
  • The valves, the pressure gauge on the discharge nozzle and the screwed plug on the vacuum gauge must be closed.
  • The pump shall is filled with liquid before starting. For pumps with a suction diameter equal to or less 300mm, the plug on the pump cover must be taken out and water is poured in through the plug hole on the top of the pump cover. For pumps with a suction diameter larger than 350mm, open the cock on the top of the pump cover and under the water indicator, and then start the vacuum pump. When the water level reaches the water indicator, clock the cock immediately.
  • Having done the procedure described above, start the motor and open the cock for a pressure gauge.
  • When the rated revolution of the pump is obtained and the pressure gauge shows a proper reading, open the cock for the vacuum gauge and the gate valve on the discharge pipeline gradually up to the required extent.

For stopping the pump, close the gate valve on the discharge pipe line gradually, close the cock for vacuum gauge, then stop the motor and close the cock for the pressure gauge.
Caution: when the ambient temperature is at 0℃ or below, the water remained in the pump must be drained off through the holes under the suction and discharge nozzles.
When the pump is to be out of use for a long time, it must be disassembled, cleaned and then packed for storage.

WARNINGS
  • Pay attention to the bearing temperature. The bearing temperature should not exceed the ambient temperature by 55℃ and its maximum temperature not exceed 85℃.
  • The lubricating grease should be changed after first 80 hours operation and once every 2400 hours operation afterward. The bearing housing is filled with grease, which occupies 75% of the space in it. The lubricant used for the bearings is lithium basic grease.
  • Leakage of 10 to 20 drops per minute from stuffing box is a normal phenomenon. If the leakage is too large or too small, then the stuffing gland should be tightened or loosened. The packing consists of individual round – shaped rings, the joints of which alternate by an angle of 120 degrees successively for the convenience of pressing tightly. The stuffing shall be changed when the leakage is too large.
  • The flexible coupling, the elastic washers, the screw and etc, should be inspected periodically and pay constant attention to the motor bearing temperature.
  • The pump should be inspected after each 2000 hours operation. In case the diameter clearance between the wear ring and the impeller exceeds 2mm, the wear ring should be replaced.
DISMANTLEMENT
  • Close inlet and an outlet valve, open the drain plug of bottom and air release plug of top to ensure there is no water in the pump.
  • Dismantle the entire assistant pipeline.
  • Dismantle the pin which is between shaft couplings.
  • Loosen the casing-bottom half (1) and a casing-top half (2) connecting bolts, separate the cover and casing and put the cover to a safe place.
  • Lose the connecting bolts of the left bearing housing and right bearing housing (14), loose the connecting bolts of left bearing cover and right bearing cover.
  • Pull of left and right bearing housing, load out the whole rotor and put to horizontal and safe place for dismantling.
  • Dismantle bearing housing, bolt, ball bearing, left bearing cover, slinger, left mechanical seal or gland packing, dismantle seal housing (12), left mechanical seal shaft sleeve or gland packing shaft sleeve.
  • Disassembling the impeller (4), the casing wear ring (3), and the impeller key.
  • Disassembling the coupling guard and coupling, right bearing housing (14), loose spring ring, withdraw from the bearing, removed the right bearings cover, the right slinger, the right mechanical seal (or packing seal) components, and then closed down the right seal housing.
  • Dismantle static ring of mechanical seal cover.
RE-INSTALLATION
  • Re-installing by opposite order of disassembly. When installing, all the o ring should be new, the installation place should be clean. Clean all the parts connecting and bolts, pay attention to impeller running direction.
  • Check the clearance between impeller and seal ring, if the clearance is over 1mm, should change seal ring or impeller.
  • When installing mechanical seal, the seal face should be added lubricate oil and the mechanical seal shaft sleeve should be very smooth and clean. When the static ring has been installed, should check the balance degree between face and cover.
  • When installing gland packing, the cut face of gland packing should be smooth and flat, the position of the cut face should be stagger, gland packing should be well pressed, not too tight and not too loose, otherwise, the bearing will be hot and affect the normal operation.
STORAGE
  • New pump storage: load at dry place, the longest store period is 10 month.
  • If the pump is not used for a long time, the suction valve should be shut. Running once every 3 months to ensure the pump can be operated every time.
  • If the temperature is low, should drain out the pump inner to prevent from the freeze.
  • TEL:+86-21-64092786
  • EMAIL:export@croospump.com
  • ADDRESS:No.518 Zi Xu Road,Minhang District ShangHai,China