Do You Understand The Working Principles Of These 11 Pumps

Jan 02, 2025

1. Piston pump

Basic principle: The reciprocating action of the piston inside the cylinder causes the cylinder volume to repeatedly change, in order to suck in and discharge fluid.

2. Reciprocating pump

Working principle: The rotation of the eccentric shaft is used to drive the movement of the piston through the connecting rod device, converting the circular rotation of the shaft into the reciprocating motion of the piston. The piston continuously moves back and forth, and the suction and pressure processes of the pump alternate continuously.

Special structure

3. Water ring vacuum pump

Working principle: The impeller of the water ring vacuum pump blade is eccentrically installed inside the cylindrical pump casing. Inject a certain amount of water into the pump. When the impeller rotates, 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. Due to the lack of concentricity between the pump casing and impeller, the intake space 4 between the right half hub and the water ring gradually expands, forming a vacuum that allows gas to enter the intake space inside the pump through the intake pipe. Subsequently, the gas enters the left half, and due to the gradual compression of the volume between the hub rings, the pressure increases. As a result, the gas is discharged outside the pump through the exhaust space and exhaust pipe.

4. 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 extracted gas is drawn into the space v0 between the rotor and the pump casing through the intake port, and then discharged through the exhaust port. Due to the fully enclosed state of the v0 space after inhalation, there is no compression or expansion of gas in the pump chamber. But when the top of the rotor rotates past the edge of the exhaust port and the v0 space is connected to the exhaust side, due to the high gas pressure on the exhaust side, a portion of the gas rushes back into the v0 space, causing a sudden increase in gas pressure. When the rotor continues to rotate, gas is expelled from the pump.

Generally speaking, Roots pumps have the following characteristics:

● Has a large pumping speed within a wide pressure range;

● Fast start-up, able to work immediately;

Not sensitive to dust and water vapor contained in the extracted gas;

The rotor does not need lubrication, and there is no oil in the pump chamber;

Low vibration, good rotor dynamic balance conditions, and no exhaust valve;

Low driving power and minimal mechanical friction loss;

● Compact structure and small footprint;

Low operation and maintenance costs.

Therefore, Roots pumps have been widely used in the metallurgical, petrochemical, papermaking, food, and electronics industries.

5. Rotary vane vacuum pump

Working principle: Rotary vane vacuum pump (referred to as rotary vane pump) is an oil sealed mechanical vacuum pump. Its working pressure range is 101325~1.33 × 10-2 (Pa), which belongs to low vacuum pumps. It can be used alone or as a pre pump for other high vacuum pumps or ultra-high vacuum pumps. It has been widely used in production and scientific research departments such as metallurgy, machinery, military industry, electronics, chemical industry, light industry, petroleum, and medicine.

The rotary vane pump is mainly composed of pump body, rotor, rotary vane, end cover, spring, etc. Install a rotor eccentrically in the cavity of the rotary vane pump, with the outer circle of the rotor tangent to the surface inside the pump cavity (with a small gap between the two), and two spring equipped rotary vanes installed in the rotor slot. When rotating, the top of the rotor is kept in contact with the inner wall of the pump chamber by centrifugal force and spring tension, and the rotor rotates to drive the rotor to slide along the inner wall of the pump chamber.

Two rotary blades divide the crescent shaped space enclosed by the rotor, pump chamber, and two end caps into three parts: A, B, and C. When the rotor rotates in the direction of the arrow, the volume of space A connected to the suction port gradually increases and is in the process of suction. The volume of space C connected to the exhaust port is gradually decreasing and is currently undergoing the exhaust process. The volume of the central space B is gradually decreasing and is currently undergoing compression. Due to the gradual increase in volume (i.e. expansion) of space A, the gas pressure decreases, and the external gas pressure at the pump inlet is greater than the pressure inside space A. Therefore, the gas is sucked in. When space A is isolated from the suction port, that is, when it turns 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 fuel tank and is discharged into the atmosphere. The continuous operation of the pump achieves the purpose of continuous pumping. If the discharged gas passes through the airway and enters another stage (low vacuum stage), it is pumped out by the low vacuum stage and then compressed by the low vacuum stage before being discharged into the atmosphere, forming a two-stage pump. At this point, the overall compression ratio is borne by two stages, thus increasing the ultimate vacuum degree.

6.Submersible pump

Working principle: The submersible pump is to drive the impeller to rotate at high speed through an electric motor, and use centrifugal force to suck and discharge liquid from the suction pipe. When the submersible pump is started, the impeller begins to rotate, and the liquid is thrown out under the action of centrifugal force. The speed gradually slows down in the diffusion chamber of the pump casing, the pressure gradually increases, and finally flows out from the discharge pipe. At the same time, a vacuum low-pressure zone is formed at the center of the blade, and the liquid in the liquid pool is sucked into the pump under atmospheric pressure, forming a continuous suction and discharge process. ‌

The design features of submersible pumps include "no entanglement, no blockage", and some models are also equipped with tearing mechanisms or cutting devices, which can handle long fibers and ribbons in water. However, submersible pumps have limitations on the sand content of the medium, and when the sand content is high, it is easy to damage the seal, which may lead to motor water ingress, bearing and winding insulation damage, and ultimately result in motor burnout.

7. Internal gear pump

What to pay attention to during runtime

(1) Check if the equipment has been carefully and completely installed

(2) The pressure liquid can only be filled with the minimum volume ratio through the filter

(3) Pay attention to the arrow pointing in the direction of rotation

(4) Run the pump without load and let it run without pressure for a few seconds to achieve sufficient lubrication

(5) Never run the pump without oil

(6) If there is still gas after running the pump for 20 seconds, check the pump again After reaching the operating value, check the sealing of the pipeline connection

(7) Check the operating temperature

8. External gear pump

Working principle: The external gear pump is to achieve the suction and discharge of liquid through the rotation of two gears. When the gear rotates, the volume between the teeth gradually decreases, and the liquid is sucked into the pump; As the gears continue to rotate, the volume between the teeth gradually increases, and the liquid is discharged from the pump. External gear pumps typically consist of two identical gears, one is the power gear driven by an electric motor or internal combustion engine, and the other is the driven gear that rotates in the opposite direction to the power gear. ‌
The structure of an external gear pump includes two gears, a pump body, front and rear covers, and seals. During operation, two gears are driven by either an electric motor or an engine to rotate the gears. When the volume of the suction side increases, a vacuum is formed to suck in liquid; When the volume on the discharge side decreases, the liquid is squeezed out of the pump.
The advantages and disadvantages of external gear pumps include:
Advantages: relatively quiet operation, high speed, no extended bearing load, design that facilitates wide material variations, easy maintenance, and good reliability.
Disadvantages: Unable to handle liquids containing solids, with fixed end clearances, and four liners in the fluid region.
By understanding the working principle, structure, advantages and disadvantages of external gear pumps, it is possible to better select and apply this type of pump in various industrial scenarios.

9. Mud pump

Working principle: The mud pump is to achieve the purpose of pressure delivery and circulation of flushing liquid through the reciprocating motion of the piston or plunger, combined with the action of the suction and discharge valves. During the drilling process, the main function of the mud pump is to drill mud with the drill bit and inject it into the wellbore to cool the drill bit, clean the drilling tools, fix the drilling tools, and bring the drilled line back to the surface. ‌
Mud pumps are usually driven by a power engine to rotate the crankshaft, which is connected to the pump cylinder block through a crosshead. The piston or plunger performs reciprocating motion in the pump cylinder, and the combined action of the suction and discharge valves achieves the purpose of pressure feeding and circulating flushing liquid. This design ensures that the mud pump can effectively perform its function during the drilling process.

10. Pneumatic booster pump

(1) The working pressure range is large, and different types of pumps can be used to obtain different pressure zones,

Adjust the input air pressure and output air pressure accordingly. Can reach extremely high pressure, gas 90Mpa

(2) The flow range is wide, and all models of pumps can operate smoothly with only 0.1Kg air pressure. At this time, the minimum flow rate can be obtained, and different flow rates can be obtained by adjusting the intake volume.

(3) Easy to control, from simple manual control to fully automatic control, all meet the requirements.

(4) Automatic restart, regardless of the reason for the pressure drop in the holding circuit, will automatically restart to supplement the leakage pressure and maintain a constant circuit pressure.

(5) Safe operation, gas driven, no arc or spark, suitable for use in hazardous environments.

(6) The maximum energy saving can reach 70%, as maintaining pressure does not consume any energy.

11. Gas liquid booster pump

working principle

The high-pressure plunger controlled by a one-way valve continuously discharges the liquid, and the outlet pressure of the booster pump is related to the air driving pressure. When the pressure between the driving 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 it reaches pressure balance again and then stop automatically.

The pump adopts a single gas controlled non-equilibrium gas distribution valve to achieve automatic reciprocating motion, and the gas driven part of the pump body is made of aluminum alloy. The liquid receiving part is made of carbon steel or stainless steel according to different media, and the complete set of seals for the pump are imported high-quality products, thus ensuring the performance of the gas-liquid booster pump.