Classification of pumps:
The classification of pumps cannot be integrated into their working principles and uses, which would be messy. The purpose is the use, the principle is the principle, the pump of different principles can be used for the same purpose. The same pump can be used in different locations and can be used for different purposes. For example, the mixed flow pump is a diagonal flow pump, which adopts a mixed flow impeller, that is, the direction in which the liquid flows out of the impeller is inclined to the axis. The axial flow pump has a liquid outflow direction parallel to the axis. Its classification is mainly sewage pump, chemical pump, magnetic pump, oil pump, fire pump, vacuum pump, diaphragm pump, screw pump, pipeline pump, submerged pump, reciprocating pump, colloid mill, water supply and drainage equipment, water jet, holding cabinet, etc. Several of the following are listed as references:
1, the first major category is divided according to the working principle:
1), vane pump
Vane pumps can be divided into: centrifugal pumps, mixed flow pumps, axial flow pumps, vortex pumps.
Centrifugal pumps can be divided into single-stage pumps and multi-stage pumps.
Single-stage pumps can be divided into single-suction pumps, double-suction pumps, self-priming pumps, and non-self-priming pumps.
Multi-stage pumps can be divided into: segment type, volute type.
The mixed flow pump can be divided into a volute type and a vane type.
The axial flow pump can be divided into fixed blades and adjustable blades.
Vortex pumps can also be divided into single suction pumps, double suction pumps, self-priming pumps, non-self-priming pumps, etc., submersible pumps.
2), positive displacement pump
The volumetric pump can be divided into a reciprocating pump and a rotor pump.
The positive displacement pump is a reciprocating or revolving movement in the pump cylinder according to the working element, so that the working volume is alternately increased and decreased to realize the suction and discharge of the liquid. A positive displacement pump in which the working element reciprocates is called a reciprocating pump, and a rotary pump is called a rotary pump. The suction and discharge processes of the former alternate in the same pump cylinder and are held by the suction valve and the discharge valve; the latter is the rotation of the working elements such as gears, screws, lobes or vanes, forcing the liquid from The suction side is transferred to the discharge side and the sewage pump.
The flow rate of the positive displacement pump at a certain speed or reciprocating frequency is inevitable, and it hardly changes with the pressure; the flow and pressure of the reciprocating pump have a large pulsation, and the corresponding pulsation method is required; the rotary pump is generally pulsating or only small. Pulsating, diaphragm pump; with self-priming ability, centrifugal pump, pump can remove the air in the pipeline to suck in the liquid after starting the pump; the pump must be fully opened when starting the pump; the reciprocating pump is used for high pressure and small flow The rotary pump is used for medium and small flow and high pressure; the reciprocating pump is suitable for conveying clean liquid or gas-liquid mixture, chemical pump. In general, the volumetric pump is more efficient than the power pump.
3), jet pump
The high-speed jet generated by the working fluid ejects the fluid, and then the momentum of the ejected fluid is increased by momentum exchange.
The power pump relies on the force of the fast-rotating impeller to transfer the mechanical energy to the liquid, so that its kinetic energy and pressure can be increased, and then the pumping cylinder can convert most of the kinetic energy into pressure energy for transportation. Power pumps are also known as impeller pumps or vane pumps.
Centrifugal pumps are the most common power pumps.
The head of the power pump has a limited value at a certain speed. The magnetic pump and the head change with the flow; the work is stable, the self-priming pump, the delivery is continuous, the flow and pressure are not pulsating; generally, there is no self-priming, and the pump needs to be filled first. Fully liquid or pumped into a vacuum before starting work, water pump; wide range of practical properties; suitable for conveying clean liquid with very small viscosity, specially designed pump can transport mud, sewage, etc. or water to transport solids. Power pumps are important for water supply, drainage, watering, process liquid delivery, power station storage, hydraulic transmission and ship jet propulsion.
4), other classification of pumps
In addition to classification by pumping principle, pumps can be classified and named in other ways. For example, according to the driving method, it can be divided into electric pump, steam turbine pump, diesel engine pump and water wheel pump; according to the structure, it can be divided into single-stage pump and multi-stage pump; according to the use, it can be divided into boiler feed pump and metering pump; The properties of liquids can be divided into pumps, oil pumps and mud pumps.
The working principle and characteristics of the pump
First, the working principle and characteristics of the centrifugal pump
1), the working principle of the centrifugal pump
Before the pump starts, the pump and the inlet pipe are filled with water. After the pump is running, under the centrifugal force generated by the high-speed rotation of the impeller, the water in the impeller flow channel is surrounded by the squirrel, and the volute is pressed into the volute. The water in the pool is filled in along the suction pipe under external atmospheric pressure to supplement this space. The water that is inhaled is then pumped out of the volute by the impeller into the outlet pipe. It can be seen that if the centrifugal pump impeller rotates continuously, it can continuously absorb water and press water, and the water can be continuously raised from a low point to a high place or a distant place. In summary, the centrifugal pump is called a centrifugal pump because the centrifugal force generated by the high-speed rotation of the impeller raises the water.
2), the general characteristics of centrifugal pumps
(1) The flow direction of water along the centrifugal pump is sucked in the axial direction of the impeller, and flows out perpendicularly to the axial direction, that is, the direction of the inflow and outflow flows at 90° to each other.
(2) Since the centrifugal pump forms vacuum suction through the inlet of the impeller, it is necessary to inject water into the pump and the suction pipe before starting, or pump the air with a vacuum pump to form a vacuum, and the pump casing and the suction pipe must be tightly sealed. Do not leak, or it will not form a vacuum, it will not be able to absorb water.
(3) Since the absolute impregnation cannot be formed at the impeller inlet, the water absorption height of the centrifugal pump should not exceed 10 meters, and the path loss caused by the water flowing through the suction pipe actually allows the installation height (the height of the pump axis from the suction surface) to be much smaller than 10 m. If the installation is too high, it will not absorb water; in addition, because the mountain area is lower than the plain atmospheric pressure, the installation height of the same pump should be reduced when installing in the mountainous area, especially in the high mountainous area, otherwise it will not be able to absorb water.
Second, the working principle and characteristics of axial flow pump
1), the working principle of the axial flow pump
The axial flow pump and the centrifugal pump work differently, and it mainly uses the thrust generated by the high-speed rotation of the impeller to lift water. The lift generated by the axial flow pump blades as they rotate, pushing the water from below to the top.
The blades of the axial flow pump are typically submerged in a pool of water source. Due to the high-speed rotation of the impeller, under the lift generated by the blade, the water is continuously pushed upward, so that the water flows out along the outlet pipe. As the impeller rotates continuously, the water is continuously pressed to a high place.
2) General characteristics of axial flow pumps
(1) The flow direction of water in the axial flow pump is sucked along the axial phase of the impeller, and the axial phase flows out. Therefore, it is called an axial flow pump. (2) Low head (1 to 13 meters), large flow, high efficiency, suitable for irrigation and drainage in plains, lakes and river networks.
(3) No need to fill water before starting, the operation is simple.
Third, the working principle and characteristics of mixed flow pump
1), the working principle of the mixed flow pump
Since the shape of the impeller of the mixed flow pump is between the centrifugal pump impeller and the axial flow pump impeller, the working principle of the mixed flow pump has both centrifugal force and lift. By the combined action of the two, the water flows out of the impeller at a certain angle with the shaft. Lift the water up through the volute chamber and piping.
2), the general characteristics of mixed rafts
(1) Compared with the centrifugal pump, the mixed flow pump has a lower lift and a larger flow rate. Compared with the axial flow pump, the head has a higher lift and a lower flow rate. Applicable to irrigation and drainage in plains and lakes.
(2) The water is sucked and discharged at a certain angle to the impeller shaft along the flow direction of the mixed flow pump, so it is also called a diagonal flow pump.
Fourth, submersible pump, submersible pump structure, submersible pump working principle
Submersible pump
Submersible pumps are a versatile water treatment tool that can be seen in both agricultural and industrial processes. According to its application and use, it can be roughly divided into submersible sewage pump, sand submersible pump and clear water submersible pump.
The submersible pump is generally composed of a pump body, a water pipe, a pump base, a submersible motor and a starter protection device. Generally speaking, it is a kind of machine for conveying liquid which combines pump and motor. It has simple structure and convenient use.
Depending on the relative position of the pump and the motor, the submersible pump can be divided into an upper pump type and a lower pump type.
1. The upper pump submersible pump is on the top and the motor is on the bottom. This structure greatly reduces the radial size of the pump, so it is mostly used for well submersible pumps and small-scale submersible pumps.
2, the lower pump submersible pump motor is on the top, the pump is below, it is divided into two types: built-in and external.
(1) The liquid delivered by the pumped submersible pump first passes through the annular flow path surrounding the motor, so that it cools the motor and then flows out of the pump outlet. This kind of pump does not have to worry about the temperature rise of the motor even when it is close to draining the sink, so the application range is expanding.
(2) The external pump-type submersible pump directly discharges liquid from the pressure water chamber or the outlet of the vane body behind the impeller, and the motor is also cooled by the pumped liquid. Because the lower pump structure can work in shallower liquids, it is often used in working surface submersible pumps, especially it is the main structural type of large diameter submersible pumps.
(3) The mechanical seal of the lower pump submersible pump is located in the high pressure zone of the outlet water flow. The higher the lift, the higher the water pressure here, so the performance of the mechanical seal is controlled by the lift.
5. Precautions and characteristics in the use of pipeline pumps
1. During the operation of the pipeline pump, the bearing temperature should not exceed the ambient temperature of 35C, and the maximum temperature should not exceed 80C.
2. Add bearing lubrication oil to the pipeline pump bearing body. Observe that the oil level should be at the center line of the oil mark, and the lubricating oil should be replaced or replenished in time.
3. Unscrew the water plug screw of the pump body of the pipeline pump and pour the water (or the slurry).
4. Jog the pump motor to see if the motor is turning correctly.
5. Close the gate valve and outlet pressure gauge of the pipeline pump outlet pipe and the inlet vacuum gauge.
6. Start the pipeline pump motor. When the pipeline pump is running normally, open the outlet pressure gauge and the inlet vacuum pump. After it shows the appropriate pressure, gradually open the gate valve and check the motor load.
7. Try to control the flow and head of the pipeline pump within the range indicated on the sign to ensure that the pipeline pump operates at the highest efficiency point to obtain the maximum energy saving effect.
8. When the pipeline pump is to be stopped, first close the gate valve and pressure gauge, then stop the motor.
9. If the pipeline pump is found to have abnormal sound, stop it immediately and check the cause.
10. Check for looseness in the pipeline pump and piping and joints. Turn the pipeline pump by hand to see if the pipeline pump is flexible.
11. Regularly check the wear of the bushing of the pipeline pump. Replace it after the wear is large.
12. The pipeline pump will change the lubricating oil after 100 hours in the first month of work, and change the oil once every 500 hours.
13. The pipeline pump is to be deactivated for a long time. It is necessary to disassemble the pipeline pump completely, wipe off the moisture, and apply the grease to the rotating part and the joint, and keep it properly.
14. When the pipeline pump is used in the cold winter season, after parking, the water plug of the lower part of the pump body should be unscrewed to release the medium to prevent freezing cracking.
15. Regularly adjust the packing gland of the pipeline pump to ensure that the dripping in the packing chamber is normal.
6. Procedures for regular maintenance of pumps
1. Purpose
Make sure the pump is always in good running or standby.
2, the scope of application
Living water pumps installed in all buildings, fire pumps, spray pumps, pressure pumps, sewage pumps, air conditioning pumps.
3. Duties
The maintenance personnel of the management office are responsible for the regular maintenance of the pump.
4, content
1) The daily life inspection and maintenance of the daily life pump and the air-conditioning water pump are carried out once every six months.
2), fire pump and spray pump every month, the pressure pump will be tested every two months, the running time is 10-15 minutes, when the fire pump starts, the fire hydrant outlet spray range is above 6M at the top of the pipe network, every half year Carry out a comprehensive maintenance.
3) The sewage pump and submersible pump are fully maintained every six months.
4) When the pump is being serviced, the valve, pressure gauge, pipeline, etc. within 2 meters connected to the pump body should be maintained at the same time with the pump.
5), pump body maintenance
(1) Check that the pump body should be free of damage, the nameplate is intact, the direction of the water flow is clear and clear, the appearance is neat, and the paint is in good condition.
(2) Replenishing lubricating oil. If the oil is discolored and has impurities, it should be replaced.
(3) Check the packing condition of the packing. If there is any leakage, increase or replace the asbestos rope packing.
(4) If the coupling bolt and rubber pad of the coupling are damaged, they should be replaced.
(5) Fasten the machine base screws and do anti-rust treatment.
(6) Due to the frequent operation of the domestic and air-conditioning pumps, the bearings at both ends of the coupling should be dismantled or replaced every year.
6), motor maintenance
(1) The appearance inspection should be neat and tidy, the nameplate is intact, and the grounding wire is well connected.
(2) Disassemble the wire connecting piece in the motor terminal box, and test the insulation resistance value of the phase and phase of the motor winding and the ground between the ground and the ground with a 500V megohmmeter to be not less than 0.5 megohm.
(3) The three-phase wire and connecting piece in the motor junction box should be firm and tight.
7) Maintenance of related valves, pipes and accessories
(1) The switches of each valve should be flexible and reliable, with no leakage inside or outside.
(2) The check valve should be flexible and there is no water leakage inside and outside the valve.
(3) The pressure gauge is accurate and the dial is clear.
(4) The appearance of pipes and accessories is neat and beautiful, without cracks, and the paint should be intact without falling off.
(5) Jog to judge whether the pump steering is correct, and correct it if it is wrong.
8), maintenance of the control cabinet
(1) Disconnect the main power supply of the control cabinet, check each transfer switch, and activate and stop the button action should be flexible and reliable.
(2) Check whether the air switch, contactor, relay and other electrical appliances in the cabinet are in good condition, and fasten the wiring screws of the contact head and terminal of each electrical appliance.
(3) Clean the inside and outside of the control cabinet.
(4) Close the main power supply and check that the power supply indication should be normal.
9) After starting the maintenance, start the water pump and observe whether the current meter and indicator light are normal.
10) Observe that the operation of the pump should be stable, no obvious vibration and abnormal sound, the pressure gauge indication is normal, and the electrical appliances of the control cabinet have no bad noise.
5, the main pump maintenance project
SB single suction water centrifugal pump maintenance project and requirements
Operational requirements and technical requirements
1), check the stuffing box
When the pump is sealed with stuffing box, it must pay attention to the tightness of the packing. Too much water leakage will affect the performance. In normal time, the water leakage should be about 60 drops per minute. The dripping is normal, and the surrounding water splash is not normal.
2), check the mechanical seal
When the pump is mechanically sealed, it should not be operated under water cut. Only a momentary jog can be made during commissioning. When the mechanical device is in normal operation, a small amount of dripping water will flow out from the water retaining ring. When the water leakage is large, it should be checked. Rubbing the ring, repairing or replacing the mechanical seal under normal conditions, the service life is 8000 hours. Generally, it is not necessary to replace the whole set. Just change the pair of friction rings of the moving ring and the stationary ring.
3), lubricating bearings
The pump adopts imported SKF series bearings semi-closed type, which has been added with high temperature grease at the factory.