Sewage pump is a kind of centrifugal impurity pump, which has many forms, such as submersible pump and dry pump. The most common submersible pump is QW submersible sewage pump, and the most common dry sewage pump is W horizontal sewage pump and WLvertical sewage pump Two.It is mainly used to transport urban sewage, and fiber is contained in feces or liquid.Paper scraps and other solid particles are usually transportedtemperatureNot more than 80 ℃.The conveyed medium contains fibers that are easy to be wound or bunched.Therefore, the flow channel of this kind of pump is easy to be blocked. Once the pump is blocked, the pump will not work normally, or even burn the motor, resulting in poor drainage.It has a serious impact on urban life and environmental protection.Therefore, blocking resistance and reliability are important factors for the quality of sewage pump.
Sewage pump model:：PW sewage pump and PWL sewage pump.
The volute is the most common type of pressure chamber used by PW sewage pump, and radial guide vane or runner guide vane are mostly used in the built-in submersible pump.
PWL sewage pump impeller and water pressure chamber are the two core components of sewage pump.The advantages and disadvantages of its performance also represent the advantages and disadvantages of the pump performance.
With the progress of society, the continuous improvement of people's living standards and the strengthening of environmental awareness, sewage pumps have been familiar to people, and their application scope has become increasingly broad.
Sewage pump
Of course, sewage pump is just an application name. In fact, rubber liningSlurry pumpAs a horizontal sewage pump, it is very good.In the treatment of industrial sewage, because the sewage contains acidic or alkaline substances, rubber lined pumps are widely used.According to some application cases in the pump industry, rubber sleeve and metal impeller are used in rubber lined pump, which can not only achieve high pressure and efficiency of metal pump, but also give full play to the resistance of rubber materialcorrosive。When treating urban sewage, a filter screen is usually added in front of the sewage treatment pool to block the filament winding before the suction inlet of the pump, so that it cannot enter the pump chamber, so that the pump can work better and have a longer service life.
characteristic
1. With advanced technology, it has strong sewage discharge capacity and no blockage, and can effectively pass through solid particles with a diameter of φ 30 - φ 80mm.
2. The tearing mechanism can tear and cut the fiber material, and then discharge it smoothly without adding a filter screen on the pump.
3. The design is reasonable, the supporting motor power is small, and the energy-saving effect is remarkable.
4. With the latest materialsMechanical sealThe pump can operate safely and continuously for more than 8000 hours.
5. Compact structure, convenient movement and simple installation can reduce the project cost without building a pump house.
6. It can be used within the full lift range, and the motor will not be overloaded.
7. The float can automatically control the start and stop of the pump according to the required water level change, without special care.
8. Double guide rail automatic installation system, which brings great convenience to installation and maintenance, and people do not have to enter and exit the sump for this purpose.
9. The automatic protection control box is equipped to effectively protect the electric leakage, water leakage and overload of the product, improving the safety and reliability of the product.
advantage
(1) Compact structure and small floor area.Because the pump works underwater, it can be directly installed in the sewage pool without the need to build a special pump room to install the pump and motor, saving a lot of land and infrastructure costs.(2) Easy installation and maintenance.SmallSubmersible sewage pumpIt can be freely installed. Large sewage pumps are generally equipped with automatic coupling devices for automatic installation, which is very convenient for installation and maintenance.(3) Long continuous operation time.As the submersible sewage pump is coaxial with the motor, the shaft is short, and the weight of the rotating parts is light, the load (radial) on the bearing is relatively small, and the service life of the submersible sewage pump is much longer than that of ordinary pumps.(4) Low vibration and noise, motortemperature riseLow, no pollution to the environment.[1]
structure
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impeller
Like other pumps, the impeller and the pressure chamber are the two core parts of the sewage pump.The performance of the sewage pump represents the performance of the pump. The anti clogging performance, efficiency, cavitation performance, and anti abrasion performance of the sewage pump are mainly guaranteed by the vane pump and the water pressure chamber.The following is an introduction:
Impeller structure type:
The impeller structure is divided into four categories: vane type (open type, closed type), swirl type, runner type, (including single runner andDouble flowThere are four types of spiral centrifugal type.
The open and semi open impeller is easy to manufacture and can be easily cleaned and maintained when the impeller is blocked. However, in long-term operation, the clearance between the blade and the side wall of the pressurized water chamber will increase under the abrasion of particles, thus reducing the efficiency.And the increase of clearance will destroy the differential pressure distribution on the blade.Not only produce a large number ofVortexThe loss will also increase the axial force of the pump. At the same time, the stability of the flow pattern of the liquid in the flow channel will be damaged due to the increase of the clearance, which will cause the pump to vibrate. This type of impeller is not easy to transport media containing large particles and long fibers. In terms of performance, the efficiency of this type of impeller is low, and the highest efficiency is about 92% of that of the ordinary closed impeller,liftThe curve is flat.
Swirl impeller
For pumps with this type of impeller, part or all of the impeller will shrink away from the flow channel of the pressure chamber.Therefore, it has good non blocking performance, strong particle passing ability and long fiber passing ability.The particles flow in the pressurized water chamber driven by the vortex generated by the rotation of the impeller. The suspended particles do not generate energy themselves, but exchange energy with the liquid in the flow channel.In the flow process, suspended particles or long fibers do not contact with the blades, and the blades are slightly worn. There is no gap increase due to abrasion, which will not cause serious decline in efficiency in long-term operation. The pump with this type of impeller is suitable for pumping media containing large particles and long fibers.
In terms of performance, the efficiency of the impeller is relatively low, only about 70% of that of the ordinary closed impeller, and the head curve is relatively flat.
Closed impeller
The normal efficiency of this type of impeller is high.In addition, the condition is relatively stable in long-term operation, the axial force of the pump with this type of impeller is small, and auxiliary blades can be set on the front and rear cover plates.The auxiliary blade on the front cover plate can reduce the vortex loss at the impeller inlet and the wear of particles on the sealing ring.The auxiliary blades on the rear cover plate not only balance the axial force, but also prevent suspended particles from entering the mechanical seal chamber to protect the mechanical seal.However, this type of impeller has poor non blocking performance and is easy to wind, so it is not suitable for pumping untreated sewage media containing large particles (long fibers).
Runner impeller
This kind of impeller belongs to vaneless impeller, and the impeller channel is a curved channel from the inlet to the outlet.Therefore, it is suitable for pumping medium containing large particles and long fibers.Good blocking resistance.
In terms of performance, the efficiency of this type of impeller is almost the same as that of ordinary closed impeller, but this type of impellerVane pumpThe head curve drops sharply.Power curveIt is relatively stable, and it is not easy to cause the problem of overpower. However, the cavitation performance of this type of impeller is not as good as that of ordinary closed impeller, especially suitable for pumps with pressure inlets.
Spiral centrifugal impeller
The blades of this type of impeller are twistedHelical blade, extending axially from the suction inlet on the conical hub body.The pump with this type of impeller has the functions of both a positive displacement pump and a centrifugal pump. When suspended particles flow through the blades, they do not hit any part of the pump, so they are non-destructive.It is less destructive to the transported goods.Because of the propelling effect of the screw and the strong trafficability of suspended particles, the pump with this type of impeller is suitable for pumping media containing large particles and long fibers, as well as high concentration media.It has obvious characteristics when there are strict requirements for the destruction of the conveying medium.
In terms of performance, the pump has a head curve with steep drop and a flat power curve.
Water pressure chamber
The most common type of pressure chamber used for sewage pump is spiral case, which is internally mountedSubmersible pumpRadial guide vane or runner type guide vane shall be selected in the middle.There are three types of spiral casing, annular casing and intermediate casing.Spiral volute is basically not used in sewage pump.Because of its simple structure and convenient manufacture, the annular pressure chamber is widely used in small sewage pumps.However, due to the appearance of intermediate (semi spiral) water pressure chamber, the application scope of annular water pressure chamber gradually becomes smaller.Because the intermediate type water pressure chamber has both the high efficiency of spiral and the high permeability of annular water pressure chamber.More and more attention has been paid by manufacturers.
To sum up, no matter any series of sewage pump is just a combination of different types of impellers and different types of pressure chambers according to the requirements of transmission medium and installation, as long as the impellers and pressure chambers can be optimized.The performance of the pump will be guaranteed.(Of course, the design and manufacturing of other parts' structures cannot be ignored.)[2]
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Maintenance
(1) Check whether the sewage pump pipeline and joint are loose.Rotate the sewage pump by hand to see if it is flexible.
(2) Add bearing lubricating oil into the bearing body, observe that the oil level should be at the center line of the oil pointer, and the lubricating oil should be replaced or supplemented in time.
(3) Unscrew the water diversion plug of the sewage pump body, and inject water (or slurry).Self-primingSewage pump
(4) Close the gate valve, outlet pressure gauge and inlet vacuum gauge of the water outlet pipeline.
(5) Inch the motor to see if the rotation direction of the motor is correct.
(6) Start the motor and open the outlet pressure gauge and inlet when the sewage pump operates normallyVacuum pumpOpen the gate valve gradually and check the motor load when it shows proper pressure.
(7) The flow and lift of the sewage pump shall be controlled within the range indicated on the label as far as possible to ensure that the sewage pump operates at the highest efficiency point to obtain the maximum energy saving effect.
(8) During the operation of sewage pump, the bearing temperature shall not exceed the ambient temperature by 35 ℃, and the maximum temperature shall not exceed 80 ℃.
(9) If the sewage pump has abnormal sound, stop the pump immediately to check the cause.
(10) When the sewage pump is to be stopped, first close the gate valve and pressure gauge, and then stop the motor.
（11）Split pumpThe lubricating oil of the sewage pump shall be replaced after 100 hours in the first month of operation, and then every 500 hours.
(12) Regularly adjust the packing gland to ensure that the leakage in the packing chamber is normal (it is better to leak in drops).
(13) Regularly check the wear condition of the shaft sleeve, and timely replace it if it is worn seriously.
(14) When the sewage pump is used in cold winter, it is necessary to unscrew the drain plug at the lower part of the pump body to drain the medium after shutdown.Prevent frost cracking.
(15) If the sewage pump is out of service for a long time, it is necessary to disassemble all the pumps, wipe off the water, and coat the rotating parts and joints with grease.
The pump should be divided into two aspects: electrical and mechanical. For the mechanical aspect, the main thing is to call out the previous maintenance records and compare them.The second is about electricity. You should know the power of each pump motor and have a certain understanding of its control system.
It is suitable for pumping liquid containing fiber or other suspended solids below 80 ℃ for cities, mines, enterprises, sewage, feces, and some aquatic products.If the delivery of acidic and alkaline liquids and other liquids containing multi salt chemical mixtures that can cause corrosion, the order should be noted. The factory can supply pumps assembled with anti-corrosion materials.PW type is horizontal pump, PWL isVertical pump。[3]
