The working principle and performance characteristics of various pumps

The performance parameters of the pump mark the performance of the pump. The performance parameters of the pump and the relationship between them are the basis for selecting the pump and adjusting the flow. The performance differences of various pumps play a very important role in the selection and use.

Centrifugal pump

Working principle: when the centrifugal pump is working, the liquid fills the pump casing, the impeller rotates at high speed, the liquid produces high speed under the action of centrifugal force, and the high-speed liquid passes through the gradually expanding pump casing channel, and the dynamic head is transformed into static head.

Performance characteristics:

High efficiency and energy saving: the pump has an efficient hydraulic line and high work efficiency.

Convenient installation and maintenance: vertical pipeline structure, the import and export of the pump can be installed in any position and any direction of the pipeline like a valve, and the installation and maintenance are extremely convenient.

Smooth operation, safe and reliable: the motor shaft and water pump shaft are coaxial direct connection, high concentricity, stable operation, safe and reliable.

Stainless steel shaft sleeve: the mechanical seal position of the shaft is relatively easy to be corroded. Once the shaft of the straight-link pump is corroded, it is easy to cause the failure of the mechanical seal. The inlaid stainless steel shaft sleeve is used to avoid corrosion, improve the shaft life and reduce the operation and maintenance cost.

Bearings: The middle and lower shaft extension end bearings of the pump motor are closed bearings. During normal use, maintenance of the motor bearings is exempted.

Mechanical seal: mechanical seal base parts generally use rubber bellows structure, the traditional mechanical seal shaft seal from the O-ring line seal to the rubber parts of the two surface seal, in the clear medium to improve the sealing effect.

multistage centrifugal pump

Working principle: Multi-stage centrifugal pump compared with single-stage pump, the difference is that the multi-stage pump has more than two impellers, can be segmented multi-stage suction and pressure water, so as to lift the water to a very high position, head can be increased or decreased according to the needs of the pump impeller series. Multi-stage centrifugal pump has two types of vertical and horizontal, multi-stage centrifugal pump pump shaft is equipped with two in series also on the impeller, it is relative to the general single-stage centrifugal pump, can also achieve higher lift.

Multi-stage centrifugal pump is a pump composed of two or more single-stage centrifugal pumps connected in series, which can provide high pressure and flow. It is suitable for various high-pressure pumping applications, such as water supply, boiler water supply, petrochemical industry, mining metallurgy, seawater desalination, etc. The main advantages of multi-stage centrifugal pump are compact structure, high efficiency, stable operation, low noise and convenient maintenance.

According to the data, the global multistage centrifugal pump market is expected to reach $8.5 billion billion in 2023, an increase of 5.6 percent over the same period last year. Among them, the Asia-Pacific region is the largest market, accounting for 40% of the global market share, mainly driven by the rapid industrialization and urbanization process in China, India and other countries. Europe and North America are also important markets, accounting for 25% and 20% of the global market share, mainly affected by environmental regulations and energy conservation and emission reduction policies. Other regions such as the Middle East, Africa and Latin America also have certain market demand, mainly stimulated by infrastructure construction and energy development projects.

Performance characteristics: multi-stage pump is mainly used for mine drainage, urban and factory water supply. Relative to the piston pump, diaphragm pump and other reciprocating pump, can also pump a larger flow. Multi-stage centrifugal pump has high efficiency and can meet the needs of high lift and high flow conditions. It has been widely used in petrochemical, chemical, electric power, construction, fire protection and other industries. Because of its particularity, compared with single-stage centrifugal pump, multi-stage centrifugal pump has different and higher technical requirements in design, use, maintenance and repair.

self-priming pump

Working principle: before the pump starts, fill the pump shell with water (or the pump shell itself has water). After starting, the impeller rotates at a high speed to make the water in the impeller channel flow to the volute. At this time, the inlet forms a vacuum, so that the water inlet check door opens, and the air in the suction pipe enters the pump and reaches the outer edge through the impeller channel.

The performance characteristics of the self-priming pump: The self-priming pump is a self-priming centrifugal pump, which has the advantages of compact structure, convenient operation, stable operation, easy maintenance, high efficiency, long life, and strong self-priming ability. There is no need to install a bottom valve in the pipeline, and it is only necessary to ensure that a certain amount of liquid is stored in the pump body before work. Different liquid can use different material self-priming pump.

piston pump

Working principle: Piston pump is also called electric reciprocating pump, which is divided into single cylinder and multi cylinder from the structure. When the piston pump is working, the volume in the cylinder is repeatedly changed by the reciprocating action of the piston in the cylinder to suck in and discharge fluid.

Performance characteristics of piston pump:

Piston pump is suitable for high pressure, small flow occasions, especially when the flow rate is less than 100 m3/h and the discharge pressure is greater than 9.8 MPa, it shows its high efficiency and good operating performance.

Good suction performance, can pump a variety of different media, different viscosity of the liquid, can be used in oil fields, coal seam water injection, oil injection, oil production. If the flow parts are stainless steel, corrosive liquid can be transported. In addition, according to the different structure of the material can also transport high temperature tar, slime, high concentration mortar, high viscosity liquid.

Piston pumps are widely used in petrochemical industry, machinery manufacturing industry, papermaking, food processing, pharmaceutical production and so on.

hydraulic plunger pump

Working principle: The hydraulic plunger pump or solid pump is driven by the hydraulic power pack to drive the hydraulic cylinder, and the hydraulic cylinder pushes the conveying cylinder to output the material in the conveying cylinder to the pipeline.

It is generally divided into single plunger and double plunger. The basic principle of plunger pump is very simple. This pump uses the momentum of a relatively large moving water body to pump a relatively small volume of water to a high place. Hydraulic piston pumps are widely used in sewage treatment, solid waste treatment, mine metallurgy, dredging, dredging, petrochemical, power plants, cement industry and other fields.

screw pump

Working principle: twin-screw pump and gear pump is very similar, a screw rotation, drive another screw, the liquid is intercepted in the meshing chamber, along the rod axis direction, and then squeezed to the central discharge.

Advantages of screw pump:

Wide range of pressure and flow. The pressure is about 3.4-340 kgf/cm2, and the flow rate can reach 100 cm3/min;

The type and viscosity of the transported liquid are wide, and the concentrator can be used to transport collectors, flocculants, etc;

Because the rotating parts of the pump inertia force is low, it can use a very high speed;

Good inhalation performance, with self-priming ability;

Uniform and continuous flow, small vibration and low noise;

Compared with other rotary pumps, it is less sensitive to entering gas and dirt;

Solid structure, easy installation and maintenance.

Disadvantages of screw pump: screw processing and assembly requirements are higher; the performance of the pump is more sensitive to changes in the viscosity of the liquid.

gear pump

Working principle: The teeth of the two gears of the gear pump are separated from each other to form a low pressure, and the liquid is sucked in and sent to the other side along the shell wall. The other side of the two gears close to each other, forming a high pressure to discharge the liquid.

Advantages: simple and compact structure, small size, light weight, good manufacturability, low price, strong self-priming, insensitive to oil pollution, large speed range, impact load resistance, convenient maintenance, and reliable work. Disadvantages: unbalanced radial force, large flow pulsation, high noise, low efficiency, poor interchangeability of parts, difficult to repair after wear, and cannot be used as a variable pump.

reciprocating pump

Working principle: When the reciprocating pump is working, the piston moves to the right, the pressure in the cavity decreases, the upper valve is pressed down, the lower valve is jacked up, and the liquid is sucked in; the piston moves to the left, the pressure in the cavity increases, the upper valve is jacked up, and the lower valve is pressed down, The liquid is discharged.

Advantages of reciprocating pump:

High discharge pressure can be obtained, and the flow is independent of pressure, good suction performance and high efficiency, of which the steam reciprocating pump can reach 80% ~ 95%;

In principle, any medium can be transported, almost free from the physical or chemical nature of the medium;

The performance of the pump does not change with the pressure and the viscosity of the conveying medium.

Disadvantages of reciprocating pumps: the flow is not very stable. Under the same flow, it is larger than centrifugal pump; the mechanism is complex; the amount of funds is large; it is not easy to repair, etc.

double-acting reciprocating pump

Working principle: double-acting reciprocating pump work when the piston moves to the right, lower left suction, upper right discharge. The piston moves to the left, sucking liquid at the lower right and draining liquid at the upper left. The piston reciprocates once, there are two suction and drainage, and the flow is more uniform.

Mud pump

Working principle: The commonly used mud pump is piston type or plunger type. The power machine drives the crankshaft of the pump to rotate, and the crankshaft drives the piston or plunger to reciprocate in the pump cylinder through the crosshead. Under the alternating action of the suction and discharge valves, the purpose of pressing and circulating flushing liquid is realized.

Mud pump is a machine that transports mud or water to the borehole during drilling, and it is an important part of drilling equipment.
In the commonly used positive circulation drilling, the surface flushing medium-clear water, mud or polymer flushing fluid is directly sent to the bottom end of the drill bit through the high-pressure hose, faucet and the center hole of the drill string under a certain pressure, so as to achieve the purpose of cooling the drill bit, removing the cut debris and transporting it to the surface.

Pneumatic diaphragm pump

Working principle: pneumatic diaphragm pump work in order to make the live column is not in direct contact with the corrosive material, the cylinder cavity and liquid material with a diaphragm separated, the essence is the principle of reciprocating pump. Pneumatic diaphragm pump has four kinds of materials: engineering plastics, aluminum alloy, cast iron, stainless steel.

Pneumatic diaphragm pump performance characteristics using compressed air as the power source, can be used for a variety of corrosive liquids. Different materials can be used according to different liquid media to meet the needs of different users.

The pump will not overheat: compressed air power, in the exhaust is a process of expansion and heat absorption, pneumatic pump work temperature is reduced, no harmful gas discharge.

Will not produce electric sparks: pneumatic diaphragm pump does not use electric power for power, and after grounding, it prevents electrostatic sparks

It can pass through the liquid containing particles: because of the volumetric work and the inlet is a ball valve, it is not easy to be blocked.

The shear force of the material is extremely low: how to suck in and spit out during work, so the agitation of the material is minimal, which is suitable for the transportation of unstable substances.

The flow rate can be adjusted, and a throttle valve can be installed at the material outlet to adjust the flow rate.

With self-priming function.

It can be flown without danger.

Can dive work.

The fluids that can be transported are extremely wide, from low viscosity to high viscosity, from corrosive to viscous.

No complicated control system, no cables, fuses, etc.

Small size, light weight, easy to move.

No lubrication is required, so maintenance is simple and will not pollute the working environment due to dripping.

The pump can always maintain high efficiency and will not be reduced due to wear.

One hundred percent energy utilization, when the outlet is closed, the pump will automatically stop, and the equipment will move, wear, overload, and heat

No dynamic seal, easy maintenance to avoid leakage. No dead spots when working.

axial flow pipeline pump

Working principle: The impeller of the axial flow pipeline pump is designed as an axial flow type with a high speed. If the motor power, impeller diameter, and pipe diameter are large enough, the flow rate can be large.

Performance characteristics of axial flow pipeline pump:

The pipeline pump has a compact structure, integrated machine and pump, small size, and its vertical structure has a small installation area, stable operation, and no adjustment is required for installation.

The inlet and outlet of the pump are designed as flanges with the same specifications and are located in the same center online. They can be directly installed on the pipeline like valves, and the center is low, which is convenient for pipeline layout and installation.

The pump is coaxial with the motor, and the axial size is short, which makes the pump run more smoothly and has low noise.

Cancel the traditional way of shaft seal, to avoid the leakage of the transmission medium, so it has the remarkable characteristics of no leakage.

whirlpool pump

Working principle: The liquid in the groove of the blade of the vortex pump is thrown to the flow channel by centrifugal force to pressurize at one time; the liquid in the flow channel is thrown out to form a low pressure due to the liquid in the groove, and enters the groove again to pressurize again; multiple The groove flows through the vortex movement of a groove to obtain a higher pressure head.

advantages of vortex pump:

W-type single-stage directly connected vortex pump is used for suction and delivery of clear water or liquid with physical and chemical properties similar to water. The liquid temperature does not exceed 60 ℃. It is commonly used in boiler feed water matching. It is widely used in shipbuilding, textile, chemical industry, metallurgy, machinery manufacturing, aquaculture, fixed fire pressure stabilizing, heat exchange unit, agricultural remote sprinkler irrigation and other departments.

The characteristics of small volume and light weight of vortex pump have great advantages in marine equipment. With self-priming capability or by means of a simple device to achieve self-priming.

The head characteristic curve has a steep drop and is therefore insensitive to pressure fluctuations in the system. Some vortex pumps can realize vapor-liquid mixed transportation. This is important for pumping volatile liquids containing gases and high temperature liquids with high vaporization pressures.

Vortex pump structure is simple, casting and processing technology are easy to achieve, some vortex pump parts can also use non-metallic materials, such as plastic, nylon molded impeller.

Disadvantages of vortex pump:

The efficiency is low, the maximum is not more than 55%, and the efficiency of most vortex pumps is 20-40%, thus hindering its development in the direction of high power.

Vortex pump cavitation performance is poor.

Vortex pump can not be used to pump viscous medium. As the viscosity of the liquid increases, the head and efficiency of the pump will decrease sharply, and the viscosity of the medium is limited to 114 centistokes.

The radial clearance and axial clearance between the impeller and the pump body of the vortex pump are strictly required to bring some difficulties to the processing and assembly process.

The pumping medium is limited to pure liquids. When the liquid contains solid particles, it will reduce the performance of the pump or cause the vortex pump to work due to the increase of the axial and radial clearance caused by wear.

gas-gas booster pump

Working principle: The gas booster pump uses compressed air as the power to continuously output the low-pressure gas pressure, and the final output pressure can be increased to twice or even dozens of times the pressure of the power source. It is a pollution-free gas booster device. According to the output pressure and structure, it is divided into low pressure pump and high pressure pump.

The low pressure pump is mainly used to maintain the normal operation of the pneumatic device and meet the local high pressure gas requirements of the equipment when the pressure of the gas source on site is insufficient or unstable and the minimum operating pressure of the pneumatic device cannot be guaranteed. High-pressure pump is mainly used for pressurized non-ordinary compressed air occasions, such as nitrogen, helium, argon and other pressurized to tens of MPa and into the high-pressure gas tank. Performance characteristics of gas booster pump:

The working pressure range is large, and different types of pumps can be selected to obtain different pressure areas, and the input air pressure can be adjusted accordingly. Can reach extremely high pressure, gas 90Mpa

Wide flow range, only 0.1Kg air pressure for all types of pumps can work smoothly, at this time to obtain the smallest flow, adjust the air intake can be different flow.

Easy to control, from simple manual control to fully automatic control can meet the requirements.

Automatically restart, no matter what causes the pressure drop of the pressure holding circuit, it will automatically restart to supplement the leakage pressure and keep the circuit pressure constant.

Safe operation, gas driven, no arc and spark, can be used in dangerous situations.

The maximum energy saving can reach 70%, because maintaining pressure does not consume any energy.

gas-liquid booster pump

Working principle: The gas-liquid booster pump is continuously discharged from the liquid by the high-pressure plunger controlled by the one-way valve. The outlet pressure of the booster pump is related to the air driving pressure. When the pressure between the drive part and the output liquid part reaches equilibrium, the booster pump will stop running and no longer consume air. When the output pressure drops or the air drive pressure increases, the booster pump will automatically start running until the pressure balance is reached again and then automatically stops.
The single pneumatic control non-balanced gas distribution valve is used to realize the automatic reciprocating movement of the pump, and the gas drive part of the pump body is made of aluminum alloy. The liquid part selects carbon steel or stainless steel according to the different media, and the full set of seals of the pump are imported high-quality products, thus ensuring the performance of the gas-liquid booster pump. Performance characteristics of gas-liquid booster pump:

High output pressure: liquid pump up to 640MPa, air pump up to 200MPa

Wide range of use: working medium can be hydraulic oil. Water and most of the chemical corrosive liquid, and high reliability, maintenance-free long life.

Wide range of output flow: For all types of pumps, only a small driving pressure is required to work smoothly. At this time, a small flow is obtained, and different flow rates can be obtained after adjusting the driving air intake.

Flexible application: different types of pumps can be used to obtain different pressure areas.

Easy to adjust: within the pressure range of the pump, adjust the regulating valve to adjust the intake pressure, and the output hydraulic pressure will be adjusted accordingly.

Automatic pressure holding: no matter what causes the pressure of the pressure holding circuit to drop, it will automatically start to supplement the leakage pressure and keep the circuit pressure constant.

Operation safety: gas driven, no arc and spark, can be used in dangerous places.

Roots vacuum pump

Working principle: The working principle of Roots pump is similar to that of Roots blower. Due to the continuous rotation of the rotor, the gas is sucked into the space v0 between the rotor and the pump casing from the inlet, and then discharged through the exhaust port. Since the v0 space is fully enclosed after inhalation, the gas in the pump chamber is not compressed and expanded. However, when the top of the rotor turns over the edge of the exhaust port and the v0 space communicates with the exhaust side, due to the high gas pressure on the exhaust side, a part of the gas will return to the space v0, causing the gas pressure to suddenly increase. As the rotor continues to rotate, the gas exits the pump.

Roots pump has the following characteristics:

There is a larger pumping speed in a wider pressure range;

Quick start, able to work immediately;

Insensitive to dust and water vapor contained in the pumped gas;

The rotor does not need to be lubricated, and there is no oil in the pump cavity;

The vibration is small, the rotor dynamic balance condition is better, there is no exhaust valve;

The driving power is small, the mechanical friction loss is small;

Compact structure, small footprint;

Low operating maintenance costs.

Therefore, the roots pump in metallurgy, petrochemical, paper, food, electronics industry sector has been widely used.

rotary vane vacuum pump

Working principle: The rotary vane of the rotary vane pump divides the crescent-shaped space enclosed by the rotor, the pump cavity and the two end covers into three parts: A, B, and C. When the rotor rotates in the direction of the arrow, the space connected to the suction port The volume of A is gradually increasing, and it is in the process of inhaling. The volume of the space C communicating with the exhaust port is gradually reduced and is in the exhaust process. The volume of the centered space B is also gradually decreasing and is in the process of compression.

Since the volume of the space A is gradually increased (I. e., expansion), the gas pressure is reduced, and the external gas pressure at the inlet of the pump is greater than the pressure in the space A, so the gas is sucked in. When space A is isolated from the suction port, that is, to the position of space B, the gas begins to be compressed, the volume gradually decreases, and finally communicates with the exhaust port. When the compressed gas exceeds the exhaust pressure, the exhaust valve is pushed open by the compressed gas, and the gas passes through the oil layer in the oil tank and is discharged to the atmosphere. By the continuous operation of the pump, to achieve the purpose of continuous pumping. If the discharged gas is transferred to another level (low vacuum level) through the airway, it is pumped away by the low vacuum level, and then compressed by the low vacuum level and discharged to the atmosphere, which constitutes a two-stage pump. At this time, the total compression ratio is borne by two stages, thus increasing the ultimate vacuum degree. Rotary vane vacuum pump performance characteristics: Rotary vane vacuum pump is an oil-sealed mechanical vacuum pump, which is a low vacuum pump and can be used alone or as a pre-pump for other high vacuum pumps or ultra-high vacuum pumps. Widely used in metallurgy, machinery, military, electronics, chemical, light industry, petroleum and pharmaceutical production and scientific research departments.

Small size, light weight, low noise;

A gas ballast valve is provided to remove a small amount of water vapor;

With automatic anti-return check valve, easy to start;

The continuous and unobstructed atmospheric operation of the air inlet shall not exceed one minute;

It is not suitable for pumping out gases that are corrosive to metals, chemically react to pump oil, contain particles and dust, and gases that contain too much oxygen, are explosive and toxic.

Water ring vacuum pump

Working principle: The impeller of the water ring vacuum pump blade is eccentrically installed in the cylindrical pump shell. A certain amount of water is injected into the pump. When the impeller rotates, the water is thrown into the pump casing to form a water ring, and the inner surface of the ring is tangent to the impeller hub. Because the pump casing and the impeller are not concentric, the intake space between the right half of the hub and the water ring is gradually expanded, thereby forming a vacuum, so that the gas enters the intake space of the pump through the intake pipe. Then the gas enters the left half, and the pressure is increased due to the gradual compression of the volume between the hub rings, so the gas is discharged to the outside of the pump through the exhaust space and the exhaust pipe.

Advantages of water ring vacuum pump:

The structure is simple, the manufacturing precision is not high, and it is easy to process.

The structure is compact, the pump has a high number of revolutions, and can generally be directly connected to the motor without a deceleration device. Therefore, with a small structural size, large exhaust volume can be obtained, and the area occupied is also small.

The compressed gas is essentially isothermal, I .e. the temperature of the compressed gas process changes very little.

Because there is no metal friction surface in the pump cavity, there is no need to lubricate the pump, and the wear is very small. The sealing between the rotating member and the stationary member can be accomplished directly by a water seal.

The suction is uniform, the work is stable and reliable, the operation is simple, and the maintenance is convenient.

Disadvantages of water ring vacuum pump:

Low efficiency, generally around 30%, better up to 50%.

The vacuum degree is low, which is not only limited by the structure, but also limited by the saturated vapor pressure of the working liquid. Using water as working fluid, the ultimate pressure can only reach 2000~4000Pa. With oil as working fluid, up to 130Pa.

In short, because the gas compression in the water ring pump is isothermal, it can pump out flammable and explosive gases. Since there is no exhaust valve and friction surface, it can remove dust gas, condensable gas and gas-water mixture. With these outstanding features, despite its low efficiency, it is still widely used.