In the "blood vessels" of industrial production, there is a device known for its high efficiency, stability, and low consumption, which is the rotary pump! Whether it's petrochemicals, food and pharmaceuticals, or environmentally friendly ships, rotary pumps are everywhere.
Today, we will unveil its mysterious veil and take you to understand how different types of rotary pumps "show their unique abilities" and become indispensable core equipment in the industrial field!
1、 What is a rotary pump?
Rotary pump, also known as positive displacement pump, is a mechanical device that uses a rotating rotor and pump chamber to periodically change the volume of a sealed space to achieve medium transport.
Core advantages:
✅ Efficient and energy-saving, stable flow rate
✅ Adapt to high viscosity and granular media
✅ Low pulsation, low noise, easy maintenance
2、 The rotary pump family has made a big start! Which of the six types is better?
Different rotor structures determine the performance characteristics of pumps. How many of the following 6 common rotor pumps have you seen?
1. Cam rotor pump (double blade rotor pump)
Structural features: Double leaf cam rotor, spiral or three leaf shaped, not in contact with each other.
Advantages: No shear, low pulsation, suitable for conveying fragile media (such as sauce and medicine).
Application scenarios: Food and beverage, pharmaceutical, and cosmetics industries.
2. Gear pump (external/internal meshing)
Structural features: Gear meshing rotates, external meshing is suitable for high pressure, and internal meshing has lower noise.
Advantages: Simple structure, low cost, high pressure resistance.
Disadvantages: High cleanliness requirements for the medium and easy wear and tear.
Application scenarios: Lubricating oil transportation, hydraulic systems.
3. Screw pump (single/double/triple screw)
Structural features: The screw and liner form a closed cavity, and the medium advances along the axial direction.
Advantages: Large flow rate, minimal pulsation, suitable for high viscosity media such as crude oil and asphalt.
Application scenarios: Petrochemical industry, wastewater treatment.
4. Sliding vane pump
Structural features: The sliding blades in the rotor slot expand and contract with centrifugal force, forming a volume change with the pump chamber.
Advantages: Strong self-priming ability, suitable for gas containing media.
Disadvantage: The slider is prone to wear and needs to be replaced regularly.
Application scenarios: Automotive fuel delivery, vacuum systems.
5. Roots pump (three leaf/four leaf rotor)
Structural features: Two or more rotor blades rotate synchronously in reverse to transport media.
Advantages: Strong dry running ability, suitable for high viscosity and solid particle media.
Application scenarios: Environmental sludge treatment, papermaking industry.
6. Rotary piston pump
Structural features: The piston shaped rotor rotates inside the pump chamber, forming a volume change.
Advantages: High pressure resistance, wear resistance, suitable for corrosive media.
Application scenarios: Chemical raw material transportation, coating industry.
3、 The 'killer move' of rotary pumps: why have they become industry darlings?
Efficient and energy-saving: Volumetric design with minimal energy loss, more energy-efficient than centrifugal pumps!
Strong adaptability: easily cope with high viscosity, high temperature, and particulate media, it can handle things that centrifugal pumps cannot do!
Low maintenance cost: compact structure, few vulnerable parts, and short downtime for maintenance.
Accurate flow control: The flow rate is proportional to the speed, suitable for scenarios that require precise measurement (such as filling production lines).
4、 Selection guide: 5 steps to complete the procurement of rotary pumps!
Observe the characteristics of the medium: viscosity, solid content, and corrosiveness determine the material and rotor type;
Calculate flow pressure: Select rated parameters according to process requirements, leaving a margin of 10% -20%;
Choose sealing method: mechanical seal, packing seal? Consider leak prevention requirements;
Material matching: stainless steel, cast iron, special alloy? The medium corrosivity is the final say;
Special requirements: explosion-proof, variable frequency, self-priming function? Communicate the working conditions in advance!
5、 Industry application cases
Petrochemical industry: Screw pumps transport crude oil, Roots pumps treat sulfur-containing wastewater;
Food and pharmaceuticals: hygiene grade cam pump for filling yogurt, gear pump for conveying chocolate;
In the field of environmental protection, slide pumps are used to extract biogas, while rotary piston pumps are used to transport industrial waste;
Shipbuilding: The three screw pump supplies oil to the engine, and the corrosion-resistant material is suitable for seawater environment.
6、 The 'genetic code' of rotary pumps: how does the volumetric principle rewrite the transmission rules?
1. Core principle: "Mechanical ballet" of volume change
Dynamic process: The rotor and pump chamber form a closed chamber with periodic changes, and the medium is transported through three steps: volume expansion (suction), sealing (displacement), and compression (discharge).
Mathematical essence: Flow rate Q=n × V (speed n × single rotation displacement V), flow rate and speed show a strict linear relationship, with an accuracy of ± 0.5%, surpassing the "flow head curve dependence" of centrifugal pumps.
The essential difference from centrifugal pumps is that centrifugal pumps rely on the conversion of impeller kinetic energy into pressure energy, which poses risks of "air binding" and "cavitation"; The rotary pump, on the other hand, achieves a "hard output" through mechanical extrusion, eliminating the problem of gas-liquid mixing, and has a self-priming capacity of over 8 meters.
