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Introduction of various pumps, working principle, usage
 Nov 04, 2021|View:696

Water pump is a machine that conveys liquid or makes liquid pressurized. It transmits the mechanical energy of the prime mover or other external energy to the liquid to increase the energy of the liquid, mainly used to convey liquids including water, oil, acid and alkali liquids, emulsions, suspended emulsions and liquid metals.

Can also transport liquids, gas mixtures and liquids containing suspended solids. Technical parameters of water pump performance are flow rate, suction range, head, shaft power, water power, efficiency, etc.; according to different working principles can be divided into volume pumps, vane pumps and other types. Volume pump is the use of its studio volume changes to transfer energy; vane pump is the use of rotary vane and water interaction to transfer energy, there are centrifugal pumps, axial flow pumps and mixed flow pumps and other types.


Vacuum Assisted Centrifugal Pump


Working principle

1, volumetric pump: the use of working chamber volume cycle change to transport liquid.

2, vane pump: the use of vane and liquid interaction to convey the liquid.

Vacuum Assisted Centrifugal Pump

1、The working principle of Vacuum Assisted Centrifugal Pump

Before the pump is started, the pump and the inlet pipe are filled with water, and after the pump is running, the water in the impeller runner is thrown around under the action of centrifugal force generated by the high-speed rotation of the impeller and pressed into the worm shell, the impeller inlet forms a vacuum, and the water in the pool is sucked along the suction pipe under the external atmospheric pressure to replenish the space. Then the inhaled water is thrown out by the impeller through the snail casing and into the discharge pipe. It can be seen that if the impeller of centrifugal pump keeps rotating, it can continuously absorb and press water, and the water can be continuously lifted from low to high or far away. In summary, the centrifugal pump is called centrifugal pump because the water is lifted to a high place under the action of centrifugal force generated by the high-speed rotation of the impeller.

2、General characteristics of Vacuum Assisted Centrifugal Pump


Mixed Flow Pump


(1)The flow direction of water along the centrifugal pump is along the axial inhalation of the impeller, perpendicular to the axial outflow, that is, the inlet and outlet water flow direction is 90° to each other.

(2) Because the centrifugal pump relies on the impeller inlet to form a vacuum to absorb water, so before starting, the pump and the suction pipe must be filled with water, or pumped with a vacuum pump, in order to discharge the air to form a vacuum, and the pump casing and suction pipeline must be strictly sealed, no air leakage, otherwise the vacuum can not be formed, and can not absorb water.

(3) Since the impeller inlet cannot form an absolute vacuum, the suction height of the centrifugal pump cannot exceed 10 meters, plus the water loss along the suction pipeline, the actual allowable installation height (the height of the pump axis from the suction water surface) is far less than 10 meters. If it is installed too high, it will not absorb water; in addition, because the atmospheric pressure in mountainous area is lower than that in plain area, the installation height of the same pump should be lowered when it is installed in mountainous area, especially in high mountainous area, otherwise it cannot absorb water either.

Vertical Axial Flow pump

Working principle and characteristics of Vertical Axial Flow pump

1、Working principle of Vertical Axial Flow pump

Vertical Axial Flow pump is different from the working principle of centrifugal pump, it mainly uses the thrust generated by the high speed rotation of the impeller to lift water. Axial pump vane rotation of the water generated by the lifting force, the water can be pushed from below to above.

Axial flow pump vanes are generally submerged in the pool of the water being sucked. As the impeller rotates at high speed, under the action of the lift force generated by the vane, the water is continuously pushed upward, so that the water flows out along the outlet pipe. The impeller rotates continuously, and the water is continuously pressed to a high place.

2、The general characteristics of Vertical Axial Flow pump

(1)The direction of water flowing through the axial flow pump is along the axial intake and axial outflow of the impeller, so it is called axial flow pump.

(2)Low head (1~13m), high flow rate and high efficiency, suitable for drainage and irrigation in plain, lake and river areas.

(3) No irrigation before starting, simple operation.

Mixed Flow Pump

1、Working principle of Mixed Flow Pump

Because the impeller shape of Mixed Flow Pump is between the impeller of centrifugal pump and the impeller of axial flow pump, therefore, the working principle of Mixed Flow Pump has both centrifugal force and lift force, and the water flows out of the impeller at a certain angle with the shaft, and the water is lifted to a higher place through the worm chamber and pipeline.

2、The general characteristics of Mixed Flow Pump

(1) Compared with centrifugal pump, mixed flow pump has lower head and larger flow rate, compared with axial flow pump, higher head and lower flow rate. It is suitable for drainage and irrigation in plain and lake areas.

(2)The water is drawn in and out along the direction of flow of mixed flow pump and the impeller shaft at an angle, so it is also called oblique flow pump.

Commonly used agricultural pumps

Centrifugal pumps

Centrifugal pump models, varieties and specifications and their variants are the most numerous among agricultural pumps. According to the way water flows into the impeller, how much the impeller, whether the pump body can self-priming and supporting power size and power varieties, centrifugal pumps have single-stage single-suction centrifugal pump, single-stage double-suction centrifugal pump, multi-stage centrifugal pump, self-priming centrifugal pump, electric motor pump and diesel engine pump, etc.

1、Single-stage single-suction centrifugal pump

Single-stage single-suction centrifugal pump, the water enters the impeller from one side of the axial direction, and there is only one impeller, so it is called single-stage single-suction centrifugal pump. Its characteristics are, compared with mixed flow pumps, axial flow pumps, higher head, smaller flow, simple structure, easy to use.

(1) performance range pump caliber 50 ~ 200 mm, flow 12.5 ~ 400 m3 / h, head 8 ~ 125 m, supporting power diesel engine direct connection, belt drive, motor direct connection, power 1.1 ~ 110 kW, speed 1450 ~ 2900 rpm.

(2) structure type light small centrifugal pump for axial suction single-stage single-suction suspension centrifugal pump, the pump body back open, the outlet is located in the center up, the back cover for the pressure embedded type, bearing body and pump body direct linkage, pump foot is located in the pump body below, bearing with grease lubrication, shaft seal is divided into soft packing, mechanical seal, rubber oil seal three. Impeller are closed type, transmission is divided into coupling drive and belt drive. Pump impeller steering: from the pump inlet direction, the impeller steering is clockwise, when the pump and diesel engine direct drive, counterclockwise. The pump outlet can be equipped with a manual pump, which can remove the bottom valve, reduce the hydraulic loss, and enable the pump to self-priming.

2、Single-stage double-suction centrifugal pump


Vertical Axial Flow pump


It is a single-stage double-suction centrifugal pump that feeds water from both sides of the impeller, because the pump cover and the pump body are assembled with horizontal joints, also known as horizontal open centrifugal pump. Compared with single-stage single-suction centrifugal pump, it has high efficiency, high flow rate and high head. However, it is large in size, relatively bulky and generally used for fixed operation. It is suitable for hilly and plateau medium area irrigation area, and also for factories, mines, urban water supply and drainage, etc.

Single-stage double-suction centrifugal pumps are available in S, Sh, SA and SLA models. the difference between S and Sh models is that, from the driving end, S pumps rotate clockwise and Sh pumps rotate counterclockwise. SLA models are vertical single-stage double-suction centrifugal pumps.

The performance range of S-type pump is 160~18000 m3/hour, 12~125m head, 150~1400mm inlet diameter, 2950, 1450, 970, 730, 585, 485, 360 rpm.

(1)D pump performance range Flow rate 6.3~720m3/h, head 16~600m, inlet diameter:50, 75, 100, 125, 150, 200mm, where 50~125mm pump type is high speed 2950rpm, 150~200mm pump type is 1480rpm.

(2) Structure type D type multistage centrifugal pump is horizontal multistage (2~12 stages), impeller is single suction, pump body is segmented. When the first stage impeller is double-suction, it is indicated by DS, and when two speeds are specified at the same time, the low speed is indicated by DA, and the multistage centrifugal pump used for boiler feed water is indicated by DG.

3、Self-priming centrifugal pump

Self-priming pump is a single-stage single-priming centrifugal pump that produces self-priming effect by the special structure of the pump itself, called self-priming centrifugal pump. Compared with ordinary centrifugal pumps, there are significant differences in the structure of the pump body: First, the pump inlet position is raised, and sometimes a suction valve is installed; second, a gas-water separation chamber is set up on the water outlet side.

Pump outside the self-priming pump, is in addition to the pump with self-priming device, such as with a vortex pump, water ring vacuum pump, jet pump, and manual pump.

Compared with ordinary centrifugal pumps, self-priming pumps have a compact structure, simple operation, not only eliminates the trouble of filling a lot of water before starting, but also eliminates the low valve of the inlet pipe, reducing the resistance to water intake and increasing the pump output, but compared with the efficiency of ordinary centrifugal pumps of the same specification is 3% to 5% lower. Self-priming pumps are more often used in light and small sprinkler irrigation units and pipeline irrigation units.

Submersible electric pump

The magnetic levitation submersible electric pump has achieved a major breakthrough in the world of submersible electric pumps, effectively solving the drawbacks of traditional submersible electric pumps: such as low conversion efficiency, high power consumption, limited head, fragile bearings, frequent maintenance, etc.. It is widely used in the fields of water supply and drainage of industrial and mining enterprises, agricultural irrigation and water supply in plateau and mountainous areas.


Submersible sewage pump

Adopting polymer composite material

During the work of the pump, the water flowing in the pump is affected by its friction with the surface of the runner and pump impeller and the viscosity of the water body, and the energy consumed by the pump is mainly used to resist the flow friction and vortex resistance of the water surface. Water in the flow process of the energy consumed (head loss) is used to overcome the internal friction and water and equipment interface friction. If the pump, impeller surface is smooth (this surface is called hydraulic smooth surface) surface resistance is small. Energy consumption is small, in the pump overflow surface and impeller spray polymer composite material, so that the surface of the surface to form a hydraulic smooth surface, ultra-smooth surface coating surface finish is after polishing stainless steel 20 times, this extremely smooth surface reduces the stratification of fluid in the pump, thus reducing the internal turbulence of the pump, reducing the volume loss and hydraulic loss in the pump, reducing the power consumption. Achieve the purpose of reducing the water flow resistance loss, so as to improve the hydraulic efficiency of the pump, and at the same time, to a certain extent, can also improve the mechanical efficiency and volumetric efficiency. The dense molecular structure of the coating can isolate the contact between air, water and other media and the mother material of the pump impeller to minimize electrochemical corrosion and rusting. In addition, the polymer composite material is a polymer with chemical resistance, which can improve the corrosion resistance of the pump and can greatly enhance the pump's ability to resist erosion and corrosion.
Use

Practical application

It is widely used in shipbuilding, oil exploration, load carrier, etc. In 2008, the production of ships reached 15,000 tons and the number of deadweight tons accounted for 21% of the world market, and will become the world's first shipbuilding country by 2015. In order to ensure the normal navigation or mooring of the ship, to meet the needs of the crew and passengers, each ship should be equipped with a certain number of marine pumps that can play a corresponding role, and the marine pump is one of the important auxiliary machines. According to incomplete statistics, in a variety of ship auxiliary machinery and equipment, the total number of various types and different uses of marine pumps, accounting for about 20%-30% of the total ship machinery and equipment, the price of marine pumps in the cost of ship equipment also accounts for a relatively large proportion. In the total cost of construction, marine pumps account for about 4%-8% of the ship equipment costs, in general, a medium-sized ship above the purchase of marine pumps up to more than 10 million yuan. Speaking of the key pump market, we must say that China has completed the "West-East gas transmission" project, "West-East gas transmission" project in the same need for pump products. At the same time, the country will also build other natural gas pipelines, in these projects also need a large number of pumps.

Different uses

Water pumps have different uses, different liquid media, different flow, different head range, so of course, its structure is not the same, the material is also different, in summary, can be divided into:

1, urban water supply 2, sewage systems 3, civil engineering, construction systems 4, agricultural water conservancy systems 5, power station systems

6, chemical systems 7, petroleum industry systems 8, mining and metallurgy systems 9, light industry systems 10, ship systems
Classification
Folding classification by use

Transfer pump, circulation pump, fire pump, test pump, sewage pump, metering pump, sanitary pump, dosing pump, paste pump, liquid pump, defoaming pump, process pump, oil pump, water pump, drainage pump, dredge pump, dredge pump, sprinkler pump, booster pump, high pressure pump, insulation pump, high temperature pump, low temperature pump, condensate pump, heat network pump, cooling pump, HVAC pump, deep well pump, pain pump, chemotherapy pump, pumping pump, blood pump, pumping material pump, desulfurization pump, shear pump, grinding pump, fuel pump, fish pump, bathtub pump, source heat pump, filter pump, oxygen pump, shampoo pump, injection pump, inflatable pump, gas pump, beauty pump, add odor pump, shredding pump.
Collapse by industry

Petroleum pump, metallurgical pump, chemical pump, fishery pump, mining pump, electric pump, water pump, water treatment pump, food pump, brewing pump, pharmaceutical pump, beverage pump, oil refinery pump, seasoning pump, paper pump, textile pump, dyeing pump, pottery pump, paint pump, pesticide pump, fertilizer pump, sugar pump, alcohol pump, environmental protection pump, salt pump, beer pump, starch pump, water supply pump, heating pump, agricultural pump, garden pump, aquarium pump, boiler pump, medical pump, ship pump, aviation pump, automobile pump, fire pump, cement pump, air conditioning pump, nuclear pump, mechanical pump, gas pump, oil and gas mixed pump
Collapse classification by principle

Reciprocating pump, piston pump, piston pump, diaphragm pump, rotor pump, screw pump, liquid ring pump, gear pump, sliding vane pump, roots pump, roller pump, lobe pump, peristaltic pump, perturbation pump, vane pump, centrifugal pump, axial flow pump, mixed flow pump, vortex pump, jet pump, jet pump, water hammer pump, vacuum pump, rotary casing pump, hose pump, worm gear pump
Folded classification by medium

Clear water pump, sewage pump, sea water pump, hot water pump, hot oil pump, thick oil pump, machine oil pump, heavy oil pump, residual oil pump, asphalt pump, impurity pump, slurry pump, sand slurry pump, gray slurry pump, gray slag pump, mud pump, cement pump, concrete pump, powder pump, acid and alkali pump, air pump, steam pump, oxygen pump, ammonia pump, gas pump, blood pump, foam pump, emulsion pump, paint pump, sulfuric acid pump, hydrochloric acid pump, colloid pump Alcohol pump, beer pump, wine pump, chocolate pump, milk pump, starch pump, wort pump, toothpaste pump, salt and brine pump, brine pump, lye pump, molten salt pump, grease pump, pesticide pump, fertilizer pump, pharmaceutical pump, gas-liquid pump, oil agent pump, chemical fiber pump, spinning pump, dose pump, paint pump, fruit pulp pump, pulp pump, insulin pump, thick pulp pump, air pump, water pump, oil pump
Installation method

1. The pump should be as close to the water source as possible to reduce the length of the suction pipe under the condition that the geographical environment permits. The foundation at the installation of water pump should be firm, and a special foundation should be repaired for fixed pumping station.

2. The inlet pipe should be sealed and reliable, and must have special support, not hanging on the pump. The inlet pipe with bottom valve should be installed vertically with the horizontal surface as far as possible, and the angle between its axis and the horizontal surface should not be less than 45°. When the water source is a channel, the bottom valve should be more than 0.50m above the water bottom, and the net should be added to prevent debris from entering the pump.

3. The base of the machine and pump should be level, and the connection with the foundation should be firm. When the machine and pump belt drive, the belt tight side in the next, so that the transmission efficiency is high, the pump impeller should be turned in the same direction as the arrow; when using coupling drive, the machine and pump must be coaxial line.

4. the installation position of the pump should meet the requirements of the allowable vacuum height, the foundation must be horizontal and stable to ensure that the direction of rotation of the power machinery is consistent with the direction of rotation of the pump.

5. If there are more than one unit in the same room, there should be more than 800mm distance between the unit and the unit, and between the unit and the wall.

6. The suction pipe of the pump must be well sealed, and the elbow and gate valve should be reduced as much as possible, and the air should be exhausted when filling the priming water, and no air should be accumulated in the pipe when running, and the suction pipe should be slightly inclined and connected with the water inlet of the pump, and the water inlet should be submerged to a certain depth.


Caution

1, if the pump has any small fault remember not to let it work. If the packing of the pump shaft is worn out, it should be added in time, if the pump continues to be used, it will leak. The direct effect of this is that the motor energy consumption will increase and then the impeller will be damaged.

2, if the pump in the process of using a strong vibration must stop to check what is the reason, otherwise the same will cause damage to the pump.

3、When the bottom valve of the pump is leaking, some people will use dry soil to fill in the inlet pipe of the pump and flush it with water to the bottom valve, which is not desirable. Because when the dry soil is put into the inlet pipe, when the pump starts to work, the dry soil will enter the pump, which will damage the pump impeller and bearing, and shorten the service life of the pump. When the bottom valve leaks, you must take it to repair, if it is very serious, then you need to replace the new one.

4, the pump must pay attention to maintenance after use, for example, when the pump is used up to put the water in the pump clean, it is best to be able to remove the water pipe and then flush with water.

5, the tape on the pump should also be removed, and then rinsed with water and dried in the light, do not put the tape in a dark and humid place. The tape of the water pump must not be stained with oil, and do not apply something with stickiness on the tape.

6、Check carefully whether there are cracks on the impeller, whether the impeller is fixed on the bearing is loose, if there are cracks and loose phenomenon to repair in time, if there is mud on top of the water pump impeller should also be cleaned up.

After the occurrence of the chemical, it will form a lot of steam and gas mixture of small vapor bubbles. When the vapor bubble with the water flow from the low-pressure area to the high-pressure area, the vapor bubble in the role of high pressure rupture, high-pressure water at a very high rate of flow to these original vapor bubble occupied space, the formation of a shock. Metal surface under the action of water impact pressure, the formation of fatigue and severe damage. Therefore, the process of formation, development and rupture of vapor bubbles, resulting in damage to the material, is called cavitation.

Reasons for loss of efficiency

1, due to the scouring of the water, the inner wall of the pump runner and impeller over the water surface becomes rough and uneven, the friction coefficient of the flow channel in the pump increases, coupled with the flow of water in the pump is very large, the head loss increases. Hydraulic efficiency is reduced.

2、Serious scale or corrosion in the pump casing due to the drug or water quality before the pump. The serious accumulation of scale in the pump casing can make the pump casing wall thickness increased by about 2ram, and the formation of scale tumor on the inner wall of the pump, so that the volume of the pump body is reduced, the pumping volume is reduced, and the flow channel is rough, and the head loss is increased. The guest volume efficiency and hydraulic efficiency are reduced.

3, due to the pump processing technology caused by the casting

Diaphragm pump manufacturing defects, cavitation, abrasion, corrosion and chemical immersion causes cavities or cracks in the pump flow channel, water flow vortex and cause energy loss. Hydraulic efficiency is reduced.

4, the impeller surface cavitation. Due to the negative pressure generated by the blade backwater surface operation, when the pressure Pk < Pva, the generation of vapor cavities and honeycomb surface, after the role of electrochemical corrosion, so that the pump leaves cavitation.

5, volume loss and mechanical loss. Due to the long use of the pump, mechanical wear produces leakage and resistance increases, so that the volume efficiency and mechanical efficiency is reduced.

The above reasons, so that the pump performance becomes poor. The operating efficiency is reduced by 2~5%, and the serious one can make the pump efficiency reduced by more than 10%.

Vibration cause analysis

Water pump vibration cause analysis leads to the unit and the pump room building to produce vibration for more reasons, some factors are related and interact with each other, in summary, there are mainly the following four aspects of the reasons.

Electrical aspects

Motor is the main equipment of the unit, the internal magnetic imbalance of the motor and other electrical system disorders, often cause

submersible pump vibration and noise. Such as asynchronous motor in operation, by the stator-rotor tooth harmonic flux interaction between the stator-rotor radial alternating magnetic tension, or large synchronous motor in operation, the stator-rotor magnetic center inconsistency or air gap difference in all directions exceeds the allowable deviation value, etc., may cause the motor periodic vibration and noise.

Mechanical aspects

Unbalanced quality of motor and pump rotating parts, crude manufacturing, poor installation quality, asymmetry of unit axis, oscillation exceeding the allowed value, poor mechanical strength and stiffness of parts, wear and tear damage of bearings and sealing parts, and resonance caused by the critical speed of the pump appearing with the inherent frequency of the unit all the time, etc., will produce strong vibration and noise.

Hydraulic aspects

Water pump inlet flow rate and pressure distribution is not uniform, the pump import and export working liquid pressure pulsation, liquid

Water pump control valve bypassing, partial flow and deliquescence, non-scheduled working conditions and pump cavitation caused by various reasons, etc. are common causes of vibration of the pump unit. Pump start and shutdown, valve opening and closing, change of working conditions and emergency shutdown and other dynamic transition process caused by rapid pressure changes in the water pipeline and water hammer, etc., also often lead to vibration of the pump room and the unit.

Hydraulics and other aspects

The unreasonable design of water inlet channel or mismatch with the unit, improper depth of pump submergence, as well as unreasonable start-up and shutdown sequence of the unit will worsen the water inlet conditions, produce vortex, induce cavitation or aggravate the vibration of the unit and the pump room. When starting the unit that adopts the siphon vacuum break, if the air in the hump section is difficult to carry, the siphon time is too long; the flapper door of the unit that breaks the flow is unreasonably designed, and it opens and closes at times, and it keeps hitting the flapper door seat; the uneven sinking of the foundation that supports the pump and motor or the poor rigidity of the foundation will also cause the vibration of the unit.

When users choose the pump, it is best to go to the sales point approved by the agricultural machinery department, and be sure to identify the manufacturer. It is recommended that priority be given to the purchase of water-filled submersible electric pumps, and look at the brand name and product quality certificate. Never buy "three no" (i.e. no manufacturer, no production date, no production license) products, otherwise there will be problems, the user will be helpless.

As a user, due to the limitations of professional knowledge, it is difficult to decide, the best way is to consult the pump connoisseur, may also wish to consult some old pump users, especially those who are similar to their own conditions of use, buy these users trust, reliable quality and more mature products, is a wise choice. At the same time, you should decide to use single-phase pump or three-phase pump according to the local power supply situation.

Noise reasons


The noise of the water pump may have the following aspects

Water pump causes:

(1) the impact of the rotary vane on the cylinder, the sound of the residual volume of the water pump and the pressure oil in the exhaust dead space;

(2) The impact of the exhaust valve piece on the valve seat and support parts;

(3) Echo and bubble rupture sound inside the box;

(4) Bearing noise;

(5) a large amount of gas, oil impact on the oil baffle plate and other noise caused by;

(6) Other. Such as transmission-induced noise, fan noise of air-cooled water pump, etc.

(7) Motor noise, which is the crucial factor.

Water leakage failure

1 The operator added cooling water to the cooling water radiator is seawater, causing damage to the internal waterway and external interface of the diesel engine. Therefore, the use of diesel engines must be strictly in accordance with the provisions of the diesel engine.

2 operators to the water radiator added within the antifreeze corrosive stronger, resulting in damage to the diesel engine waterway parts.

3 seal ring wear or aging, resulting in sealing surface can not be sealed, resulting in water leakage.

Troubleshooting

1 dismantle the diesel engine has been damaged parts, the water radiator and the internal waterway of the body with fresh water to finish flushing, replace the damaged diesel engine parts.

2 by assembly, adjustment, test engine found that the diesel engine back to normal, the fault is eliminated.

Water contamination

The method of fuel adulteration with water intake pipe spraying water and emulsified diesel fuel and other issues.

1, intake pipe water spray

The main role of the intake pipe water spray is to absorb heat and dilute the fuel density. When a small amount of water into the combustion chamber and atomized well, due to the water vapor "micro-burst" effect of oil droplets broken into smaller droplets, thus promoting the formation of the mixture and combustion. In the combustion process due to the role of water heat absorption can make the highest combustion temperature is reduced, such as water and oil mixed into the spray can reduce the fuel density, so that the highest combustion temperature is further reduced, so NOx emissions are reduced. It should be noted that the water storage tank needs to be protected from freezing in winter, and it is required to automatically adjust the amount of water sprayed with the size of the load, etc.

2、Emulsified diesel

In the diesel fuel mixed with water, that is, emulsified diesel fuel, due to its "emblem explosion" effect, so that its fuel atomization good I good, well prompted the formation of strong turbulence in the combustion chamber air, fuel and air distribution more uniform, the generation of carbon smoke reduced. Water vapor water gas reaction also reduces the carbon soot emissions. In addition, emulsified diesel fuel can reduce the maximum combustion temperature, so NOx generation is reduced.
Maintenance Solution

Water pump in the long-term operation process, often appear pump bearing frame bearing chamber wear, bearing bit wear, pump body crack rupture, pump cavitation, scouring wear, etc.. After the above-mentioned problems, the traditional solution is welding or brushing after machining repair, but both have certain drawbacks: welding high temperature thermal stress can not be completely eliminated, easy to cause material damage, resulting in parts bending or fracture; and brush plating by the coating thickness restrictions, easy to flake, and the above two methods are used to repair metal metal, can not change the "hard to hard" with the relationship, in the force of the integrated Under the combined effect of forces, it will still cause re-wear. Contemporary western countries use polymer composite repair methods for the above problems, which have superb adhesion, excellent compressive strength and other comprehensive properties. The application of polymer material repair, can be free of disassembly and machining. At the same time, the product has a metal material does not have the concession, can absorb the impact vibration of the equipment, to avoid the possibility of re-wear, and greatly extend the service life of the equipment components, for enterprises to save a lot of downtime, to create huge economic value.

Static balance of the impeller

The structure of the centrifugal pump pump rotor works at high speed, if its mass is not balanced, a large centrifugal force will be generated when it rotates, causing the pump to vibrate or be damaged. The balance of the rotor is achieved by balancing the mass of each component on it (including shaft, impeller, sleeve, balance plate, etc.), so the newly changed impeller should be subjected to static balance calibration work. The specific methods are:

(1) the impeller is mounted on the false shaft and put on the static balance test bench which has been adjusted to the level. There are two tracks on the test bench, and the dummy shaft can roll freely on it.

(2) Make a mark on the side of the impeller that is biased. If the impeller mass is unbalanced, the heavier side always turns to the bottom automatically. In the symmetrical position of the weighted place (i.e., the lighter side), increase the weighted block (with face sticky or with clamps to increase or decrease the iron piece) until the impeller can be stopped at any position.

(3) Weigh out the mass of the weighted block. Instead of adding weight on the lighter side of the impeller, the balance of the impeller is achieved by reducing the weight on the heavier side. When reducing the weight, the impeller can be milled by milling machine or ground by grinding wheel (when the removal amount is not large), but note that the depth of milling or grinding shall not exceed 1/3 of the thickness of the impeller cover plate. the impeller after static balance, the allowable deviation value of static balance shall not exceed the product of the impeller outer diameter value and 0.025g/mm. For example, for an impeller of 200mm diameter, the permissible deviation is 5g.

Disassembly and installation of the coupling

(1) When dismantling the coupling, do not directly hit with a hammer but should be padded with a copper rod, and should play the coupling hub at

Water pump coupling and can not play the outer edge of the coupling, because it is very easy to be broken. The most ideal way is to disassemble the coupling with a captive. For small and medium-sized pumps, the coupling is easy to take down because of the small amount of interference. For larger pumps, the coupling has a large interference with the shaft, so the coupling must be heated when disassembled. (2) When assembling the coupling, pay attention to the serial number of the key (for the coupling with more than two keys). If a brass rod is used to strike, attention must be paid to the part to be struck. For example, if you hit the end face of the shaft hole, it will easily cause the shaft hole to shrink, so that the shaft cannot be worn; if you hit the outer edge of the wheel, it will easily destroy the straightness of the end face, which will affect the accuracy of the measurement when you use the stopper to find the correctness later. For the coupling with large amount of interference, it should be heated and then installed.

(3) Coupling pins, nuts, washers and gaskets must ensure that their respective specifications and sizes are consistent, so as not to affect the dynamic balance of the coupling. The coupling bolt and the corresponding coupling pin hole should be marked accordingly to prevent misassembly.

(4) Coupling and shaft fit are generally used in the transition fit, there may be a small amount of interference, there may also be a small amount of clearance, for the hub longer coupling, can use a looser transition fit, because its shaft hole is longer, due to rough surface processing uneven, in the assembly will naturally produce part of the interference. If the fit of coupling and shaft is found to be too loose, which affects the concentricity of hole and shaft, then it should be patched and welded. Playing pockmark or pad copper skin on the shaft is expedient and cannot be the ideal method.
Collapse edit this paragraph technical requirements

The so-called head refers to the required head, and not the height of the water, clear this point is particularly important for the selection of pumps. The pump head is about 1.15~1.20 times the height of the water. If the vertical height of a water source to the water use is 20 meters, the required head is about 23~24 meters.

When choosing a pump, the head on the nameplate of the pump should be close to the required head, with a general deviation of no more than 20%, in which case the efficiency of the pump is the highest, and it is more energy efficient and economical to use. If the head on the nameplate is much smaller than the required head, the pump often cannot meet the needs of users, even if it can pump water, the amount of water is also very small. But in turn, the high head of the pump for low head, there will be too much flow, resulting in motor overload, if a long time running, the motor temperature rises, winding insulation will gradually aging, and even burn the motor.


Introducing the requirements of horizontal water pumps for use conditions

Features of horizontal water pumps

The water pump produced by the factory is suitable for pumping and draining sewage and sludge in various harsh environments. The water pump is down-suction type, capable of pumping the surface water on the working surface, and the motor is water-filled hetero-submersible three-phase step motor. It can work in long term diving and can also be exposed to the water surface. It covers a small area, easy to install and use, reliable and durable, and has a long life. The following is an introduction to the conditions of use of horizontal water pump.

Horizontal water pump conditions of use

Horizontal water pump is a water lifting machine with motor and pump directly connected in one submerged body. It is mainly used in agricultural irrigation, urban, industrial and mining enterprises' water supply and drainage projects.

Horizontal water pump use to power requirements:

1. The rated frequency is 50 Hz, and the rated voltage at the motor end should be 380 plus or minus 5% of the three-phase AC power supply (if the user voltage is 660 volts, special order is required)

2. The transformer load power should not exceed 75% of its capacity.

3. When the transformer is far from the well, the transmission line pressure drop should be considered. For the motor with power greater than 45KW, the distance from the transformer to the wellhead should not exceed 20 meters, and when it is greater than 20 meters, the transmission line specification should be two grades larger than the cable specification, and the line pressure drop should be considered.

Horizontal water pump using water quality requirements:

1、General non-corrosive clear water

2, the sand content in the water is not more than 0.01% (quality ratio)

3, pH PH value in the range of 6.5-8.5

4、Chloride ion content in the water is not greater than 400 mg / l

5, hydrogen sulfide content is not greater than 1.5 ml g / l

6、The water temperature is not higher than 20℃.

Summary of the use environment and conditions of the horizontal water pump:

1、The power frequency is 50hz, rated voltage is 380v or 660v (the difference is plus or minus 5%) of three-phase AC power.

2, the volume ratio of solids in the conveying medium is below 2%, and the density of the conveying medium is 1.2 x 10.

3, the temperature of the conveying medium does not exceed 40 degrees.

4、The PH value of the conveyed medium is 4-10.

5, without the set of sewage submersible pump unit, from the motor cooling state, the electric pump motor is allowed to reveal the water surface for a short period of operation not more than 0.5 hours.

6、The depth of submergence shall not exceed 20m with the center of impeller as the reference.
Selection method

The flow rate of the pump, that is, the water output, generally should not be selected too large, otherwise it will increase the cost of purchasing the pump. It should be selected according to the need, such as the user's family use of self-priming water pump, the flow should try to choose a smaller; such as the user's submersible pump for irrigation, it is appropriate to choose a larger flow.

1) To buy pumps according to local conditions. There are three types of agricultural pumps in common use, namely centrifugal pumps, axial flow pumps

Water pumps and mixed-flow pumps. The centrifugal pump has a high head, but the water output is not large, which is suitable for mountainous areas and well irrigation areas; the axial flow pump has a large water output, but the head is not too high, which is suitable for plain areas; the mixed flow pump has a water output and head between the centrifugal pump and axial flow pump, which is suitable for plain and hilly areas. Users have to buy and sell according to the ground conditions, water source and the height of the water.

2) To properly exceed the standard selection pump. After determining the type of pump, consider its economic performance, especially pay attention to the head and flow of the pump and its matching power selection. It must be noted that there is a difference between the head (total head) stated on the label of the pump and the water head (actual head) in use, which is due to the resistance loss when the water flows through the water pipe and near the pipeline. Therefore, the actual head is generally 10%-20% lower than the total head, and the water output is reduced accordingly. Therefore, the actual use, only according to the label of the head and flow rate of 80% to 90% estimate, the choice of pump supporting power, can be selected according to the power indicated on the label, in order to make the pump start quickly and use safety, the power of the power machine can also be slightly greater than the power required by the pump, generally higher than about 10% is appropriate; if there is power, the purchase of water pumps, then the power of the power machine can be purchased according to the power of the matching with it. Water pump.

3) To be strict procedures to purchase water pumps. When purchasing, we should examine the "three certificates", namely agricultural machinery promotion license, production license and product inspection certificate, only the three certificates can avoid the purchase of obsolete products and inferior products.
Fold the number of units to choose

1, the normal operation of the pump, generally only one, because a large pump and the parallel work of two small pumps equivalent, (referring to the head, the same flow), the large pump efficiency is higher than the small pump, so from the energy-saving point of view, rather choose a large pump, without two small pumps, but in the following cases, two pumps can be considered in parallel cooperation: the flow is very large, a pump can not reach this flow.

2, for the need to have 50% of the spare rate of large pumps, two smaller pumps can be changed to work, two standby (a total of four)

3, for some large pumps, can choose 70% of the flow requirements of the pump parallel operation, without backup pump, in a pump maintenance, the other pump still bear the production of 70% of the delivery.

4, the need for 24-hour continuous operation of the pump, should be spare three pumps, one operating, one standby, one maintenance.
Fold to identify the true and false

First, the original pump or supporting manufacturers' product packaging is generally more standardized, with clear and formal handwriting, detailed product name, specifications, registered trademark, factory name, factory address and telephone number, etc.; counterfeit parts are generally rougher packaging, factory address, factory name printing is not clear.

Second, the qualified pump surface is smooth and well-made. The more important the spare parts, the higher the processing precision, the stricter the packaging rust and corrosion prevention. If you find that the parts have rust spots or rubber parts are cracked, lose elasticity or have bright processing patterns on the surface of the journals, they should not be the original parts.

Third, the appearance of poor quality pumps is sometimes good. But because of the poor production process, it is easy to be damaged. When buying, just observe the hidden parts such as the sides and corners of the parts, you can see how good or bad the parts process is.

Fourthly, some pumps are refurbished with used parts, then you can find the old paint when you set aside the paint on the surface of the parts, such pumps are best not to use.

Fifth, buy the spare parts to the car, to see if it can and it accessories have a good match. Generally, the original parts can be well matched to the car, while the poor quality parts are difficult to match well with each other because of the poor workmanship and large processing errors.

Sixth, in order to ensure that the assembly relationship of the pump meets the technical requirements, some regular parts are engraved with assembly marks on the wrapping surface, which are used to ensure the correct installation of the parts, if there is no mark or the mark is blurred and unrecognizable, it is not a qualified part.

Seventh, the regular pump assembly and parts must be complete to ensure smooth loading and normal operation. If some small parts on the assembly are missing, it is easy to start to install the car causing difficulties, and such parts may be counterfeit parts.

Eighth, some important accessories, especially assemblies, generally come with manuals and certificates of conformity to guide users in installation, use and maintenance, counterfeit assemblies generally do not have detailed installation manuals to guide these.