First, multi-stage centrifugal pump product overview: Six, multi-stage centrifugal pump product structure description The multi-stage centrifugal pump is multi-stage segmented type, the suction port is located on the water inlet section, and is horizontally oriented. The discharge port is vertically upward on the water section, and the head can increase or decrease the number of pump stages according to the needs of use. Whether the pump is assembled well or not has a great influence on the performance, especially the outlet of each impeller and the entrance and exit center of the guide vane. The slight deviation will reduce the flow of the pump and the efficiency of the lift will be poor. Therefore, it is necessary to pay attention to the inspection and assembly. . 10. Loading, unloading, starting, running and stopping of multi-stage centrifugal pumps: (1) Matching sequence:
Multistage centrifugal pump for the delivery of clean water and liquids with physicochemical properties similar to water. The pump has a head of 19-245.7m and a flow rate of 18 to 162m3/h. The maximum temperature of the liquid does not exceed 80 ° C, and is widely used in mine drainage, factory and urban water supply.
Multi-stage centrifugal pump for conveying clean water or liquid with physical and chemical properties similar to water without temperature at 80 ° C. It is suitable for use in mines and urban water supply and drainage projects for -20 ° C ~ 105 ° C, excluding Solid particles, corrosive liquid, the inlet of the pump is allowed to have a pressure of 0.6MPa. The pump is used to transport neutral mineral water with a solid particle content of not more than 1.5% (particle size less than 0.5 mm) and similar other sewage. The temperature of the medium to be transported is not More than 80 °C, suitable for steel plants, mine drainage, sewage transportation and other occasions.
Second, multi-stage centrifugal pump product features:
1. Advanced hydraulic model, high efficiency and wide performance range.
2. The pump runs smoothly and the noise is low.
3. The shaft seal adopts soft packing seal or mechanical seal. The seal is safe and reliable, the structure is simple, and the maintenance is convenient and quick.
4. The shaft is a full-sealed structure, ensuring that it does not come into contact with the medium, does not rust, and has a long service life.
Third, the multi-stage centrifugal pump model meaning
For example: 80D12*5
80-suction port diameter (mm)
D-multistage centrifugal pump
12-single stage head (m)
The number of 5-impellers is to improve the operating efficiency of multi-stage centrifugal pumps, reduce the energy consumption of equipment, analyze the factors affecting the efficiency of multi-stage centrifugal pump sets, and propose improvement measures.
Four factors affecting the efficiency of multistage centrifugal pumping unit
The efficiency of a multistage centrifugal pump is the product of three efficiencies: mechanical, volume and hydraulic. The efficiency of the pump set is the product of the efficiency of the multistage centrifugal pump and the efficiency of the motor. The main factors that cause the low efficiency of the multistage centrifugal pump set are as follows.
1. The efficiency of the multistage centrifugal pump itself is the most fundamental. For pumps under the same working conditions, the efficiency may differ by more than 15%.
2. The operating condition of the multi-stage centrifugal pump is lower than the rated working condition of the pump, the pump efficiency is low, and the energy consumption is high.
3. Motor efficiency remains essentially unchanged during operation. Therefore, it is important to choose a high-efficiency motor.
4. The impact of mechanical efficiency is primarily related to design and manufacturing quality. After the pump is selected, the post management impact is small.
5. Hydraulic losses include hydraulic friction and local resistance losses. After the pump runs for a certain period of time, the surface of the impeller and the vane and the like are inevitably worn, the hydraulic loss is increased, and the hydraulic efficiency is lowered.
6. The volume loss of a multi-stage centrifugal pump is also called leakage loss, including three leakage losses of the impeller seal ring, the interstage, and the axial force balance mechanism. The volumetric efficiency is not only related to design and manufacturing, but also related to post management. After the multi-stage centrifugal pump is continuously operated for a certain period of time, the gap is increased and the volumetric efficiency is lowered due to friction between the components.
7. The centrifugal pump is evacuated and idling due to blockage of the filter cylinder, intake of the pipeline, and the like.
8. Before the multi-stage centrifugal pump is started, the employees do not pay attention to the preparation work before the start of the centrifugal pump. The basic operating procedures such as the warm pump, the disc pump and the infusion pump are not completely performed, which often causes the cavitation phenomenon of the pump, causing the pump to have large noise and large vibration. Multistage centrifugal pumps are less efficient.
V. Measures to reduce the energy consumption of multistage centrifugal pumps and improve the efficiency of pump sets
1. Replace 14 inefficient multistage centrifugal pumps. When replacing, the centrifugal pump is selected to be close to the actual operating conditions, ensuring that the multistage centrifugal pump after replacement is always operating at an efficient state. We did the efficiency comparison experiment before and after the centrifugal pump replacement. The experiment shows that after replacing the inefficient and high-consumption centrifugal pump, the pump efficiency can be increased by about 10%.
2. The application of frequency conversion energy-saving technology. For centrifugal pumps with design parameters greater than the actual operating conditions, after installing the variable frequency speed control device, it always runs in the high efficiency zone.
3. Promote the application of new energy-saving products such as high-efficiency and energy-saving permanent magnet speed regulating motors and dual power motors on the main centrifugal pumps.
4. The choice of multistage centrifugal pumps. When selecting a new pump, the pump produced by a large manufacturer should be selected to ensure high efficiency of the centrifugal pump.
5. Multistage centrifugal pump maintenance
(1) Always check and adjust the shaft end seal of the multistage centrifugal pump to reduce the volume loss;
(2) After the cumulative operation of the multistage centrifugal pump is 10,000 hours, it should be overhauled to restore the pump efficiency;
(3) Promote the application of bellows sealing technology on multi-stage centrifugal pumps to completely eliminate the leakage of multi-stage centrifugal pumps and improve the volumetric efficiency.
6. Clean the filter cylinder regularly, check the pipeline connection, and ensure that the multi-stage centrifugal pump inlet pipe is unblocked.
7. Strictly follow the multi-stage centrifugal pump operating rules. Before starting the pump, the disc pump should be opened, the inlet valve should be opened, the outlet valve should be closed, and the exhaust gas should be vented to check whether the inlet pressure of the pump meets the requirements. Prevent cavitation of the pump due to low supply pressure and insufficient flow.
8. Regularly pump the multi-stage centrifugal pump for pump efficiency. For pump units with low pump efficiency, find the cause in time and take corresponding measures to solve it.
When a multistage centrifugal pump is used to pump a slurry stream containing large, medium, and small sized materials in a liquid, the liquid is sprayed tangentially into the cylindrical chamber to form a vortex, and a portion of the liquid is tangentially removed from the Room exclusion; the slurry is sprayed axially into the chamber, the vortex separating the large size material from the rest of the mud and liquid; the remaining mud and liquid are axially removed from the chamber and sprayed into the multistage centrifugal pump The inlet from the centrifugal pump is used as the injection liquid for forming the vortex, thereby reducing the wear of the multistage centrifugal pump impeller and improving the efficiency of the multistage centrifugal pump.
A method for reducing the wear of a multistage centrifugal pump impeller and improving the efficiency of a centrifugal pump when a multistage centrifugal pump is used to pump a slurry stream containing a large to small size material in a liquid, characterized in that it comprises: a cutting the liquid Forming a vortex into the vortex chamber and removing a portion of the liquid tangentially from the chamber; b injecting the slurry axially into the chamber, the vortex separating the large sized material from the remaining mud and liquid remaining; c removing the remaining mud and liquid from the chamber in the axial direction and spraying it into the inlet of a centrifugal pump; d using the material from the centrifugal pump as the ejection liquid forming the vortex; therefore, the large The sized material is discharged toward the outer circumference of the vortex, and as a result, medium, small, and sized materials and liquid are sprayed into the multistage centrifugal pump, thereby reducing the wear of the impeller and allowing the pump to operate at a high speed. Therefore, the efficiency is improved.
The main components of the multi-stage centrifugal pump are: inlet section, middle section, outlet section, impeller, guide vane flap, outlet section guide vane, shaft, seal ring, balance ring, bushing, tail cap and bearing body.
The inlet section, the middle section, the vane baffle, the outlet section guide vane, the outlet section and the tail cap are all made of cast iron, which together form the working chamber of the pump.
The impeller is made of high-quality cast iron, with blades inside, and the liquid enters in one side in the axial direction. Because the impeller is subjected to different pressures before and after, there is bound to be an axial force. This axial force is borne by the balance disc, and the static balance test is carried out during the manufacture of the impeller. .
The shaft is made of high-quality carbon steel with an impeller in the middle and is fixed to the shaft with a key, bushing and bushing nut. One end of the shaft is fitted with a coupling member that is directly connected to the motor.
The sealing ring is made of cast iron to prevent the high-pressure water of the pump from leaking back into the water inlet part, and is fixed on the water inlet section and the middle section respectively, which is a wearing part, and can be replaced by spare parts after being worn.
The balance ring is made of cast iron and is fixed on the water outlet section. It is combined with the balance to form a balancing device.
The balance disc is made of wear-resistant cast iron and is mounted on the shaft between the water outlet section and the tail cover to balance the axial force.
The bushing is made of cast iron and is located at the packing chamber. It is used as a fixed impeller and protects the pump shaft. It is a wearing part and can be replaced with spare parts after wear.
The bearings are single row radial ball bearings lubricated with calcium based grease.
The packing acts as a seal to prevent air from entering and a large amount of liquid from leaking out. The packing seal is composed of a packing chamber on the inlet section and the tail cap, a packing gland, a packing ring and a packing, and a small amount of high-pressure water flows into the packing chamber to function as a water seal. The tightness of the packing must be appropriate, not too tight or too loose, and the liquid can be oozing one drop at a time. If the packing is too tight, the sleeve is prone to heat and consumes power. The packing is too loose and the efficiency of the pump is reduced due to fluid loss.
Seven, multi-stage centrifugal pump performance range:
Flow rate Q: 6.3~600m3/h
Head H: 17~850m
Seven, D type multi-stage centrifugal pump model description:
100 D 16 * 3
100 is the pump inlet diameter of 100mm
D is a multistage centrifugal pump
16 is the pump single-stage design point lift
1) Install the seal ring tightly on the inlet section and the vane baffle.
2) Set the guide vane on the middle section and then install the guide vane on all the middle sections.
3) Pass the installed shaft sleeve and the suspected shaft through the water-repellent section and push it into the impeller. Place a paper pad on the middle section, install the middle section, and push the second impeller. Repeat the above steps. , all the impellers and the middle section are finished.
4) Install the balance ring, balance sleeve and outlet section guides on the water section.
5) Install the water outlet section on the middle section, and then tighten the inlet, middle and outlet sections with tension bolts.
6) Install the flat plate and the sleeve B (the 50DB pump does not have this piece).
7) Put the paper pad on the tail cover, install the tail cover on the water outlet section, and insert the packing and packing ring and the packing gland into the filling chamber of the inlet section and the tail cap in sequence.
8) Install the bearing body above the inlet section and the tail cap, and fasten them with bolts.
9) Insert the bearing positioning sleeve, ball bearing, and secure with a nut.
10) Put a proper amount of butter in the bearing body, and put the paper pad on the bearing cover, and attach the bearing cover to the bearing body to tighten with screws.
11) Install the coupling parts, vent the cock and all the square plugs.
Disassembly is carried out without the reverse steps.
(2) Multistage centrifugal pump installation:
1. Preparation before installation.
1) Check the water pump and motor.
2) Prepare tools and lifting equipment.
3) Check the basis of the machine.
2, the installation sequence:
1) The whole set of pumps is transported to the site. The motor with the base is installed, and the base can be leveled without removing the pump and motor.
2) Place the base on the foundation, pad the wedge-shaped horn near the anchor screw, and raise the base to a height of about 20-40 mm, ready to be leveled and filled with water slurry.
3) Check the level of the base with a spirit level. After leveling, tighten the foot nut to fill the base with cement slurry.
4) After 3-4 days of cement drying, check the level.
5) Wash the dirt on the support plane, pump foot, and motor foot of the base; and place the pump and motor on the base.
6) Adjust the level of the pump shaft. After leveling, properly tighten the nut to prevent it from moving. Install the motor after the adjustment is completed. Leave a gap between the iron plate pump and the coupling at the level of the level.
7) Place the flat ruler on the coupling and check if the pump shaft line and the motor shaft line are coincident. If it is not heavy, pad the sheet under the foot of the motor or pump to make the outer circumference of the two couplings The flat feet are level, then remove a few pieces of thin iron from the mat, replace the iron with a piece of polished iron, and recheck the installation.
In order to check the accuracy of the installation, the gap between the planes of the two couplings is measured with a feeler gauge at several opposite positions. The maximum and minimum gap difference between the two sides of the coupling plane must not exceed 0.3 mm, and the center line of the two ends is lower or left and right. The difference must not exceed 0.1 mm.
(3) Starting and stopping:
1) Apply oil from the shaft and other oiled parts.
2) Clean the bearing and oil chamber with gasoline and wipe it with cotton yarn.
3) Add calcium base oil to the bearing body.
4) The test is successful. Check if the motor steering is correct. Strictly waterproof the pump to rotate and loosen the nut. Then start the motor.
5) Fill the pump with water or air pump.
6) Close the valve on the spit tube and the pressure gauge cock.
7) After the above process is completed, start the motor. Open the pressure gauge cock
8) When the pump is running at normal speed, the pressure gauge shows the appropriate pressure. Then open the vacuum table and gradually open the gate valve on the drain line to the required pressure.
9) When stopping the pump å‹. Slowly close the gate valve on the drain line. Close the vacuum gauge cock and stop the motor. Then close the pressure gauge cock.
10) When the pump is stopped for a long time, the pump should be disassembled. Wipe off the water of the pump parts and apply anti-rust oil on the sliding surface for proper storage.
(4) Operation
1) Pay attention to the pump bearing temperature. Do not exceed the external temperature 351. The limit temperature is not much larger than 751^
2) The normal leakage level in the grave material room is not more than 15 ml per minute. The packing gland should be adjusted at any time.
3) Check the shaft shaft regularly and pay attention to the temperature rise of the motor bearing.
4) During operation, if a voice or abnormal sound occurs, stop immediately and check the cause.