Pump
Pumps are machines that transport fluids or pressurize fluids. They are mainly used to transport water, oil, slurries, acid-base liquids, emulsions, suspoemulsions, gas mixtures, and liquid metals. They are commonly used in mining, chemical, and metallurgical industries. Equipment, 16 kinds of pumps (gear pump, centrifugal pump, screw pump, reciprocating pump, piston pump, hydraulic plunger pump, mud pump, pneumatic diaphragm pump, axial flow pipeline pump, self-priming pump, vortex pump, water ring vacuum pump, roots vacuum pump, rotary vane vacuum pump), in order to give you a certain amount of pump selection and use help.
1. Gear pump
working principle
The teeth of the two gears of the gear pump are separated from each other, forming a low pressure, the liquid is sucked in, and sent to the other side along the shell wall. The two gears on the other side are closed together to form a high pressure to discharge the liquid.
Advantages: simple and compact structure, small size, lightweight, good manufacturability, low price, strong self-suction, insensitivity to oil pollution, large speed range, ability to withstand impact loads, easy maintenance, and reliable work.
Disadvantages: Unbalanced radial force, large flow pulse, high noise, low efficiency, poor interchangeability of parts, difficult to repair after wear, cannot be used as a variable pump
2. Centrifugal pumps
working principle:
When the centrifugal pump is working, the liquid fills the pump casing, the impeller rotates at a high speed, and the liquid generates high speed under the action of centrifugal force.
Features:
High-efficiency and energy-saving: The pump has a high-efficiency hydraulic line and high working efficiency.
Easy installation and maintenance: vertical pipeline structure, the inlet, and the outlet of the pump can be installed in any position and any direction of the pipeline like a valve, which is extremely convenient for installation and maintenance.
Stable operation, safe and reliable: The motor shaft and the water pump shaft are coaxial and directly connected, with high concentricity, stable operation, safety, and reliability.
Stainless steel shaft sleeve: The mechanical seal position of the shaft is relatively easy to corrode. Once the direct-connected pump shaft is corroded, it is easy to cause the mechanical seal to fail. The use of inlaid stainless steel shaft sleeves avoids corrosion, improves shaft life, and reduces operation and maintenance costs.
Bearing: The bearing of the lower shaft extension end of the motor equipped with the pump adopts a closed bearing, and the maintenance of the motor bearing is free during normal use.
Mechanical seal: The base part of the mechanical seal generally adopts the rubber bellows structure, and the seal on the shaft of the traditional mechanical seal is changed from the line seal of the O-ring to the two-face seal of the rubber part, which improves the sealing effect in the case of clean water.
3. Multistage Centrifugal Pumps
working principle:
Compared with the single-stage pump, the multi-stage centrifugal pump is different in that the multi-stage pump has more than two impellers, which can absorb and press the water in multiple stages, so as to lift the water to a high position, and the lift can be adjusted according to Increase or decrease the number of stages of the pump impeller as needed.
There are two types of multi-stage centrifugal pumps: vertical and horizontal. The pump shaft of the multi-stage centrifugal pump is equipped with two impellers connected in series. Compared with the general single-stage centrifugal pump, it can also achieve higher lift.
Features:
Multistage pumps are mainly used for mine drainage, and city and factory water supply. Compared with reciprocating pumps such as piston pumps and diaphragm pumps, it can also pump at larger flow rates. The multistage 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.
Due to its own particularity, compared with single-stage centrifugal pumps, multi-stage centrifugal pumps have different and higher technical requirements in terms of design, use, and maintenance.
4. screw pump
working principle：
The twin-screw pump is very similar to the gear pump. One screw rotates to drive the other screw. The liquid is intercepted in the meshing chamber, pushed along the rod axis, and then squeezed to the center to be discharged.
Advantages of screw pumps:
a. Wide pressure and flow range. The pressure is about 3.4-340 kgf/cm2, and the flow rate can reach 100cm3/min;
b. The types and viscosities of the transported liquids are wide, and the concentrator can be used to transport collectors, flocculants, etc.;
c. Because the inertial force of the rotating parts in the pump is low, a high speed can be used;
d. Good suction performance and self-priming ability;
e. The flow is uniform and continuous, with little vibration and low noise;
f. Compared with other rotary pumps, it is less sensitive to incoming gas and dirt;
g. Solid structure, easy installation, and maintenance.
Disadvantages of screw pump:
High requirements for processing and assembly of screws
5. Reciprocating pump
working principle:
When the reciprocating pump works, the piston moves to the right, the pressure in the cavity decreases, the upper valve is pressed down, the lower valve is lifted, and the liquid is sucked in; the piston moves to the left, the pressure in the chamber increases, the upper valve is lifted, the lower valve is pressed, and the liquid is discharged.
Advantages of reciprocating pumps:
High discharge pressure can be obtained, and the flow rate has nothing to do with the pressure, the suction performance is good, and the efficiency is high, among which the steam reciprocating pump can reach 80%~95%;
In principle, any medium can be transported, almost not limited by the physical or chemical properties of the medium;
The performance of the pump does not change with the pressure and viscosity of the conveying medium.
Disadvantages of reciprocating pumps:
Traffic is not very stable. Under the same flow rate, it is larger than the centrifugal pump; the mechanism is complex; the capital consumption is large; it is not easy to maintain, etc.
6. Double-action reciprocating pump
working principle:
When the double-action reciprocating pump is working, the piston moves to the right, sucking liquid from the lower left and discharging the liquid from the upper right. The piston moves to the left, the bottom right is aspirated, and the top left is discharged. The piston reciprocates once, and there are two suction and discharge, and the flow is more uniform.
7. piston pump
working principle:
Piston pump, also called electric reciprocating pump, is divided into single-cylinder and multi-cylinder from the structure. When the piston pump is working, the volume of the cylinder is repeatedly changed by the reciprocating action of the piston in the cylinder to suck in and discharge the fluid.
The performance characteristics of the piston pump:
The piston pump is suitable for high pressure and small flow situations, especially when the flow rate is less than 100m3/h and the discharge pressure is greater than 9.8MPa, it shows its higher efficiency and good operating performance.
It has good suction performance and can suck liquids of various media and different viscosities. It can be used for water injection, oil injection, and oil recovery in oil fields and coal seams. If the wetted parts are stainless steel, they can transport corrosive liquids. In addition, according to the different structural materials, it can also transport high-temperature tar, mineral sludge, high-concentration mortar, high-viscosity liquid, etc.
Piston pumps are widely used in the petrochemical industry, machinery manufacturing industry, papermaking, food processing, pharmaceutical production, etc.
8. Hydraulic plunger pump
working principle
Hydraulic plunger pump or solid pump, the hydraulic cylinder is driven by the hydraulic power pack, and the hydraulic cylinder pushes the conveying cylinder to output the material in the conveying cylinder to the pipeline.
Generally divided into the single plunger and double plunger, the basic principle of plunger pump is very simple. This kind of pump uses the momentum of a relatively large moving water body to pump a relatively small volume of water to a high place.
Hydraulic plunger pumps are widely used in sewage treatment, solid waste treatment, mining and metallurgy, dredging, dredging, petrochemical, power plants, cement industry, and other fields.
9. Mud Pump
working principle:
The commonly used mud pump is of piston type or plunger-type. The crankshaft of the pump is driven by the power machine to rotate, and the crankshaft drives the piston or plunger to reciprocate in the pump cylinder through the crosshead. Under the alternate action of the suction and discharge valves, the purpose of pressurizing and circulating the flushing liquid is realized.
A mud pump refers to a machine that transports flushing fluid such as mud or water into the borehole during the drilling process and is an important part of drilling equipment.
In the commonly used positive circulation drilling, the surface flushing medium-water, mud or polymer flushing fluid is sent directly to the bottom of the drill bit through the high-pressure hose, the water tap, and the center hole of the drill string under a certain pressure to achieve cooling. The purpose of drilling, removing, and transporting the cuttings to the surface.
10. Air-operated diaphragm pump
working principle:
When the pneumatic diaphragm pump is working, in order to prevent the live column from directly contacting the corrosive material and liquid, the cylinder cavity is separated from the liquid material diaphragm, which is essentially the principle of the reciprocating pump. There are four kinds of materials for pneumatic diaphragm pumps: engineering plastics, aluminum alloys, cast iron, and stainless steel.
Performance characteristics of pneumatic diaphragm pump:
Using compressed air as the power source, it can be used for various corrosive liquids. Different materials can be used according to different liquid media to meet the needs of different users.
The pump will not be overheated: compressed air is used as power, and it is an expansion and heat absorption process when exhausting. When the pneumatic pump is working, the temperature is reduced, and no harmful gas is discharged.
No sparks: The pneumatic diaphragm pump does not use electricity for power, and prevents static sparks after grounding
It can pass through particle-containing liquids: because it works in positive displacement and the inlet is a ball valve, it is not easy to be blocked.
The sheer force on the material is extremely low: how to suck in and how to spit out when working, so the agitation of the material is minimal, and it is suitable for the transportation of unstable substances
The flow can be adjusted, and a throttle valve can be installed at the material outlet to adjust the flow.
With self-priming function.
It can be run dry without danger.
Can work diving.
The fluids that can be transported are extremely wide-ranging from low viscosity to high viscosity, from corrosive to viscous.
No complicated control systems, no cables, fuses, etc.
Small size, lightweight, easy to move.
No lubrication is required, so maintenance is easy, and there is no contamination of the working environment due to dripping.
The pump remains efficient at all times and is not degraded by wear.
100% energy utilization, when the outlet is closed, the pump automatically stops, the equipment moves, wears, overloads, and heats up
No dynamic seal, easy maintenance to avoid leakage. No dead spots when working.
11. Axial flow pipeline pump
working principle:
The impeller of the axial flow pipeline pump is designed to be axial flow, and the speed is very high. If the motor power, impeller diameter, and pipeline diameter are large enough, the flow rate can be large.
The performance characteristics of axial flow pipeline pump:
The pipeline pump has a compact structure, integrated machine and pump, and small volume. Its vertical structure has a small installation footprint, stable operation, and no adjustment required for installation.
The inlet and outlet of the pump are designed as flanges with the same specifications and are located on the same center line, which can be directly installed on the pipeline like a valve, and the center is low, which is convenient for pipeline layout and installation.
The pump is coaxial with the motor, and the axial dimension is short, which makes the pump run more smoothly and with low noise.
The traditional shaft seal method is cancelled, and the leakage of the conveying medium is avoided, so it has the remarkable feature of being completely leak-free.
12. Self-priming pump
working principle:
Fill the pump casing with water (or the pump casing itself has water) before starting the pump. After starting, the impeller rotates at a high speed, so that the water in the impeller channel flows to the volute. At this time, a vacuum is formed at the inlet, so that the water inlet check door is opened, and the air in the suction pipe enters the pump and reaches the outer edge through the impeller channel.
The performance characteristics of 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 there is a quantitative liquid in the pump body before work. Different liquids can be self-priming pumps with different materials.
13. Vortex Pump
working principle:
The liquid in the groove of the blade of the vortex pump is thrown to the flow channel by centrifugal force, and pressurized 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 then enters the groove again and is pressurized again; the groove is first-class for many times The swirling motion of the grooves is used to obtain higher head pressure.
The advantages of the vortex pump:
W-type single-stage direct-connected vortex pump is used for suction and delivery of clean water or liquids with physical and chemical properties similar to water. The liquid temperature does not exceed 60 °C. It is widely used in machinery manufacturing, aquaculture, fixed fire-fighting voltage stabilizer, heat exchange unit, agricultural remote sprinkler irrigation, and other departments.
The characteristics of the small size and light weight of the vortex pump have great advantages in marine installations. With self-priming capability or by means of simple means to achieve self-priming.
The head characteristic curve has a steep drop and, therefore, is insensitive to pressure fluctuations in the system. Some vortex pumps can realize gas-liquid mixing. This is of great significance for pumping volatile liquids containing gas and high-temperature liquids with high vaporization pressure.
The structure of the vortex pump is simple, and the casting and processing techniques are easy to achieve. Some vortex pump parts can also use non-metallic materials, such as plastics, nylon molded impellers, etc.
Disadvantages of vortex pumps:
The efficiency is low, the highest is not more than 55%, and the efficiency of most vortex pumps is 20-40%, thus hindering its development towards high power.
The cavitation performance of the vortex pump is poor.
Vortex pumps cannot be used to pump viscous media. The viscosity of the medium is limited to 114 centistokes (15°E) due to the dramatic reduction in the pump head and efficiency as the viscosity of the liquid increases.
The strict requirements on the radial clearance and axial clearance between the impeller and the pump body of the vortex pump bring certain difficulties to the processing and assembly process.
The pumped medium is limited to pure liquids. When the liquid contains solid particles, the axial and radial clearances will increase due to wear, which will reduce the performance of the pump or cause the vortex pump to fail to work.
14. water ring vacuum pump
working principle:
The impeller of the water ring vacuum pump blade is eccentrically installed in the cylindrical pump casing. A certain amount of water is injected into the pump. When the impeller rotates, the water is thrown to the pump casing to form a water ring, and the inner surface of the ring is tangent to the impeller hub. Since the pump casing and the impeller are not concentric, the intake space 4 between the right half hub and the water ring gradually expands, thereby forming a vacuum, so that the gas enters the intake space in 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 requirement of manufacturing precision is not high, and it is easy to process.
The structure is compact, and the number of revolutions of the pump is relatively high. Generally, it can be directly connected to the motor without the need for a deceleration device. Therefore, with a small structure size, a large exhaust volume can be obtained, and the floor space is also small.
Compressed gas is basically isothermal, that is, the temperature of the compressed gas changes very little.
Since 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 part and the fixed part can be done directly by the 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 degree of vacuum is low, which is not only limited by the structure, but more importantly by the saturated vapor pressure of the working fluid. When water is used as working fluid, the ultimate pressure can only reach 2000~4000Pa. Use 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. Because there is no exhaust valve and friction surface, it can pump out dusty gas, condensable gas and gas-water mixture. With these outstanding features, despite its low efficiency, it is still widely used.
15. roots vacuum pump
working principle:
The roots pump has the following characteristics:
Larger pumping speed in a wider pressure range;
Quick start, can 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 dynamic balance of the rotor is better, and there is no exhaust valve;
The driving power is small, and the mechanical friction loss is small;
Compact structure and small footprint;
Low operating and maintenance costs.
Therefore, Roots pumps are widely used in metallurgy, petrochemical, paper, food, and electronic industries.
16. 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 chamber, and the two end covers into three parts, A, B, and C. When the rotor rotates in the direction of the arrow, the space A connected to the suction port is divided into three parts. The volume is gradually increasing and is in the process of inhalation. And the volume of space C communicated with the exhaust port is gradually shrinking, and it is in the process of exhausting. The volume of the central space B is also gradually reduced and is in the process of compression.
Since the volume of space A is gradually increased (ie, expanded), the gas pressure is reduced, and the external gas pressure at the inlet of the pump is stronger than the pressure in space A, so the gas is sucked in. When space A is isolated from the suction port, that is, it turns to the position of space B, the gas begins to be compressed, the volume gradually shrinks, 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 is discharged into the atmosphere through the oil layer in the fuel tank. The purpose of continuous pumping is achieved by the continuous operation of the pump. If the exhausted gas is transferred to another stage (low vacuum stage) through the air passage, it is pumped away by the low vacuum stage, and then compressed by the low vacuum stage, and then discharged into the atmosphere, which constitutes a two-stage pump. At this time, the total compression ratio is borne by two stages, thereby increasing the ultimate vacuum.
The performance characteristics of rotary vane vacuum pump:
The rotary vane vacuum pump is an oil-sealed mechanical vacuum pump, which belongs to the low vacuum pump and can be used alone or as the backing pump of other high vacuum pumps or ultra-high vacuum pumps. Widely used in metallurgy, machinery, military industry, electronics, chemical industry, light industry, petroleum and medicine, and other production and scientific research departments.
Small size, lightweight and low noise;
Equipped with a gas ballast valve, which can extract a small amount of water vapor;
Equipped with automatic anti-return oil 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 particulate dust, and gases that contain too much oxygen, explosive and toxic gases.
Since the volume of space A is gradually increased (ie, expanded), the gas pressure is reduced, and the external gas pressure at the inlet of the pump is stronger than the pressure in space A, so the gas is sucked in. When space A is isolated from the suction port, that is, it turns to the position of space B, the gas begins to be compressed, the volume gradually shrinks, 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 is discharged into the atmosphere through the oil layer in the fuel tank. The purpose of continuous pumping is achieved by the continuous operation of the pump. If the exhausted gas is transferred to another stage (low vacuum stage) through the air passage, it is pumped away by the low vacuum stage, and then compressed by the low vacuum stage, and then discharged into the atmosphere, which constitutes a two-stage pump. At this time, the total compression ratio is borne by two stages, thereby increasing the ultimate vacuum.
The performance characteristics of rotary vane vacuum pump:
The rotary vane vacuum pump is an oil-sealed mechanical vacuum pump, which belongs to the low vacuum pump and can be used alone or as the backing pump of other high vacuum pumps or ultra-high vacuum pumps. Widely used in metallurgy, machinery, military industry, electronics, chemical industry, light industry, petroleum and medicine, and other production and scientific research departments.
Small size, lightweight and low noise;
Equipped with a gas ballast valve, which can extract a small amount of water vapor;
Equipped with automatic anti-return oil 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 particulate dust, and gases that contain too much oxygen, explosive and toxic gases.
