What are the characteristics of rotary lobe pumps, G type screw pumps, and gear pumps?

Features of rotary lobe pumps:

1.There are no suction and discharge valves, and their main working parts are the pump casing and rotor (such as gears, screws, cams, etc.).

2.Compared with the reciprocating pump, the rotor has a rotary motion without impact, the speed is higher, the structure is compact, and the volume is smaller.

3.The discharge pressure is generally higher, but lower than that of the reciprocating pump, the flow rate is smaller than that of the reciprocating pump, and the efficiency is lower, which is generally only suitable for conveying a small amount of liquid, and is mostly used as auxiliary equipment.

4.Most rotary lobe pumps are lubricated by the liquid they convey, so they are generally suitable for conveying liquids that are lubricating and do not contain solid particles.

5.The rotary lobe pump also discharges liquid intermittently, so the fluctuation of flow is greater than that of centrifugal pumps and smaller than that of reciprocating pumps, but it can be seen as approximately uniform.

6.When there is a liquid film on the surface of the rotor (to deliver lubricating liquids), the pump will have the ability to self-prime.

Features of progressive cavity pumps:

The rotational speed is low (generally 20r min 90r min), the mechanical wear is small, and cavitation will not occur.

The flow channel is wide, and it can convey water containing solids.

The structure of the pump body is half-open, and the operation of the pump can be observed.

The suction side flow state has little influence on the hydraulic performance, there is no special requirement for the suction pool, the foundation excavation depth is small, the construction of hydraulic buildings is simple, and the civil engineering cost is small.

The disadvantages are: large size and large footprint.

Limited by machining conditions, the pump shaft can not be too long, so the head is low, generally not more than 10m.

The height of the suction surface and the outlet surface should not change too much, otherwise it will affect the work efficiency and increase the energy consumption.

Features of gear pumps:

Its main characteristics are simple structure, small size, light weight and high speed, good self-priming performance, insensitive to oil pollution and reliable work. Gear pumps are widely used in various low-pressure systems, and can be divided into two types in structure: external meshing and internal meshing, no matter which type is a fixed pump.

Rotary lobe pump features:

1) Large flow rate, stable pressure, suitable for high viscosity medium transportation;

2) Simple structure, easy to maintain and clean;

3) Low noise, low vibration and stable operation;

4) It is suitable for conveying liquid, semi-solid and high viscosity media.

G type progressive cavity pump features:

1) It is suitable for conveying special media such as high viscosity, high temperature, easy crystallization, volatile, flammable, explosive, etc.;

2) The flow rate of the conveying medium is stable and the pressure fluctuation is small;

3) Simple structure, easy to maintain and clean;

4) Low noise, low vibration and smooth operation.

Gear pump features:

1) It is suitable for conveying low-viscosity liquids, such as water, oil, etc.;

2) Simple structure, easy to maintain and clean;

3) The flow rate is stable and the pressure fluctuation is small;

4) The noise is large, the vibration is large, and the operation is not very stable.

The lobe pump is a multi-purpose bidirectional positive displacement pump manufactured by advanced technology, which is widely used in petrochemical, fine chemical, daily chemical, pharmaceutical, food, environmental protection, papermaking, coating, metallurgy and other industries. At present, the domestic production of lobe pumps is mainly metal lobe pumps, which are suitable for clean, particle-free and fiber-free media, the overall efficiency is not high, and the particles and fibers are easy to make the pump stuck, which increases the maintenance cost and affects the normal operation of production.

The gear pump is a positive displacement rotary pump. Its working principle is that a driving gear in a pair of meshing gears is driven by the motor to rotate, and the other driven gear is meshed with the production gear and rotates, when the two teeth are gradually separated, the volume of the working space gradually increases, forming a partial vacuum, and the liquid is sucked into the liquid through the suction tube under the action of atmospheric pressure. The suction liquid is pushed out by the gears along the inner wall of the pump, and when the main and driven gears rotate, the pump continuously sucks in and discharges the liquid.

Difference: Gear pumps are generally used as metering pumps, which have a small handling but high head. The dosage is easy to control.

Rotary lobe pumps are generally used to convey a large number of liquids, and are characterized by wear-resistant and corrosion-resistant properties, especially suitable for conveying media containing solid particles, fibrous media or highly corrosive, shear-sensitive or gaseous media.

Among the following items, the flow regulation method common to gear pumps and progressive cavity pumps is () aAdjust the opening of the early bend bypass valve.

b.Change the rotational speed.

c.Change the opening of the valve on the outlet line.

d.Change the eccentricity of the rotating part mount.

Correct answer: Adjust the opening of the stool bypass valve; Change the rotational speed.

I can only briefly introduce it...

Progressing cavity pumps: Twin screw pumps.

Triple screw pump Twin screw pump.

The difference between rotary lobe pumps can be easily seen according to the above**.

The similarity: both positive displacement pumps are suitable for conveying viscous media.

The double and triple screw pumps at different points have a small gap and are suitable for conveying clean media, while the rotary lobe pump and single screw pump have a large gap and can properly convey the medium with debris.

When transporting cleaner media such as lubricating oil, gasoline, filtered **, heavy oil, asphalt and other media, twin and triple screw pumps are more suitable, and due to the nature of twin screw pumps, they are more suitable for ships or oil depots for cleaning warehouses and warehouses.

The maximum viscosity of the three-screw pump can be applied to asphalt, heating resin, etc. (760 mm2 s), and the minimum is diesel or similar medium (water, gasoline is not enough).

The maximum viscosity of the twin screw pump can reach 200000cp or more than 1500mm2 s, and it can pump low-viscosity media such as water or gasoline.

The single screw pump is suitable for medium with foreign matter at room temperature, such as sludge, dough, ink, jam and other media, and the single screw of the metal rotor can also transport complex media such as coal-water slurry, but the disadvantage is that it is not resistant to high temperature. Not suitable for low-viscosity media or grease-containing media.

Because of its simple structure, the rotary lobe pump is more suitable for high-viscosity media or high-temperature environment with more impurities, but the cost is high, the relative mechanical efficiency is low, and the noise is large during operation, which is an enhanced product of gear pump.

Therefore, the above products have their own emphasis, and it is better to consider the pump products selected according to the actual use environment.

Nanjing Industrial Pump Factory will serve you wholeheartedly.

The only wearing part of the rotary lobe pump is the mechanical seal, but the mechanical seal will not have any new problems after three or four years.

One of the screw pumps is that the rubber sleeve is easier to wear out quickly, and if it is fast, it needs to be replaced once a month, and the rotary lobe pump is more suitable for viscous materials than the screw pump.

However, rotary lobe pumps are more expensive than progressive cavity pumps.

The rotary lobe pump is made of stainless steel, and the screw pump is not, for the food industry, considering the hygiene level, it is recommended to choose a rotary lobe pump, and you can ask 361424989 me at any time if you have any questions

Both rotary lobe pumps and progressive cavity pumps are positive displacement pumps, in which their performance is basically similar – both are able to convey medium to high viscosity media smoothly and at high transfer pressures. So what is the difference between rotary lobe pump and progressive cavity pump?

The internal structure of rotary lobe pump 1, rotary lobe pump and progressive cavity pump is different. The rotary lobe pump is through two counter-rotating rotors, the volume from the feed port to the conveying port is changed from large to small, so as to achieve the purpose of conveying materials, and the progressive cavity pump is a spiral screw rotating at high speed in the rubber stator, so that the material can rotate from front to back spiral and finally discharge from the discharge port.

2. The service life of spare parts of rotary lobe pump and screw pump is different. Due to the fact that there is basically zero wear between the parts of the rotary lobe pump and the service life is longer, the wear of the flow parts mainly comes from the abrasive and corrosive chemical composition in the medium; There is friction between the rotor and stator of the progressive cavity pump, and the particulate material of the conveyor belt is easy to affect the life of the wear parts. The stator is subjected to the stresses generated by the eccentrically rotating rotor, which increases the wear between the components.

Even when conveying media without any particulate matter, the stator of progressive cavity pumps will suffer a certain amount of wear over time.

4. The speed of rotary lobe pump and screw pump is different. The rotary lobe pump has a very low speed, typically between 200 rpm and 600 rpm, and the conveyed material is output smoothly without destroying its composition. The higher speed of the screw pump leads to the centrifugal action of the conveyed material, which leads to the phenomenon that the screw pump often produces a phenomenon of different material components when conveying mixed materials, which affects the quality of the finished product the most.

Both rotary lobe pumps and progressive cavity pumps belong to the category of positive displacement pumps, and they have some similarities in working principle and structure, but there are also some significant differences between them. The main differences are as follows:

How it works:

Rotary lobe pumps: Rotary lobe pumps work by conveying fluid through volume changes between one or more vanes and the pump casing. As the blades rotate, the change in volume causes the fluid to flow from the suction end to the discharge end.

Typical types of rotary lobe pumps include: internal gear pumps, external gear pumps, and vane pumps.

Progressive cavity pumps: Progressive cavity pumps work by means of a pair of intermeshing screws that produce a volume change within the pump casing to transport fluid. As the screw rotates, the fluid moves from the suction end to the discharge end along the spiral space of the screw cavity.

Typical types of progressing cavity pumps include single progressing cavity pumps and twin screw pumps.

Structure and performance:

Rotary lobe pump: The rotary lobe pump has a simple structure and is easy to manufacture and maintain. However, due to the small gap between the blades and the pump casing, the rotary lobe pump is sensitive to suspended particles in the fluid and is prone to wear. At the same time, rotary lobe pumps perform relatively poorly in terms of high-pressure and high-viscosity fluid transfer.

Progressive cavity pump: The progressive cavity pump has good self-priming ability and can convey fluids with high viscosity and suspended particles. Progressive cavity pumps are characterized by low noise, low vibration and smooth flow output. However, the structure of progressive cavity pumps is relatively complex, and the manufacturing and maintenance costs are high.

To sum up, there are some differences between rotary lobe pumps and progressive cavity pumps in terms of working principle, structure and performance. Selecting the right pump type needs to be considered according to the specific requirements of the required application, such as flow, head, fluid properties and other factors.

The rotary lobe pump has a very low brightening speed, generally between 200 rmp and 600 rmp, and the conveyed material is smoothly output without damage to its components. The speed of the centrifugal screw pump is very high, and the conveyed material is subjected to strong impact and centrifugal force, so the centrifugal screw pump often produces different material components when transporting the mixture, which reduces the quality of the finished product. This pump is the best choice to solve this problem, so it is especially suitable for conveying mixtures and even materials containing solid particles.

f rotary lobe pump can be used to transport very viscous substances, so it is also called a colloidal screw pump. Centrifugal pumps do not have this feature.

The rotary lobe pump can be easily made into a variety with a higher output pressure, such as 15kgf cm2, which is suitable for long-distance or high-resistance dosing conveying. The rotary lobe pump is a positive displacement pump, and the transmission flow can be controlled more accurately or easily made into a variable pump. The output flow of the centrifugal pump is uncontrollable, bradmark, and decreases with the increase of body resistance; This pump has a strong self-priming capacity, while the centrifugal gear pump must be filled with liquid before moving.

The rotary lobe pump and the screw pump (thick slurry pump) are both positive displacement pumps, so their performance is basically similar - they can stably transport high-viscosity substances and have higher delivery pressures. However, the screw pump has one of the biggest drawbacks that determines its inapplicability in the occasion of hygienic requirements - due to the non-streamlined curved surface of the screw pump and numerous defects in the chamber, it is impossible to become a sanitary vacuum pump, and the damage of PTFE or rubber material on the cavity wall is more likely to cause pollution to the conveyed substance. Due to the streamlined steel structure of the rotor and the basic absence of stupid keys and non-metallic parts in the rotor chamber, the universal transfer pump is more suitable for application in industries with high health requirements such as food and beverage, medicine and so on, especially the automation of the current production line is getting higher and higher, and more and more (in-situ) cleaning (CIP) is used, which shows the importance of choosing a light positive belt local fluid pump, screw pump.

Although high-viscosity rotary lobe pumps and progressive cavity pumps are both positive displacement pumps, they differ in structure and working principle.

A high-viscosity rotary lobe pump (also known as an internal gear pump) is composed of a drive shaft and a driven shaft, and two gears (internal and external) are meshed with each other. The working principle of the high-viscosity rotary lobe pump is due to the internal meshing movement of the gear, which sucks in the liquid and squeezes the liquid out from the suction inlet of the pump, thus forming a fluid machinery that forcibly transports the liquid.

The progressive cavity pump consists of a spiral rotor and an internal bore housing. In the process of pump operation, the spiral-shaped rotor of the cave rotates in the inner bore shell, and at the same time, the trough volume of the rotor and the inner bore shell changes relatively, so that the medium continues to move forward to complete the pumping process.

In general, a high-viscosity rotary lobe pump is simpler in structure than a progressive cavity pump, but it is less efficient and wear-resistant than a progressive cavity pump when transporting high-viscosity liquids. Progressive cavity pumps, on the other hand, are more efficient in conveying highly viscous liquids, but in some cases they are prone to problems such as leakage in the pump chamber.

1. The internal structure is different. The rotor pump is to achieve the purpose of conveying materials by rotating the volume from the feed port to the conveying port from large to small through two rotors in the pump cavity, and the screw pump rotates in the rubber liquid slab through the spiral screw, and the material is finally sent out from the discharge port by rotating the spiral from front to back. 2. The difference in the life of accessories.

Since there is no friction between the rotary lobe pump components, the wear parts of the rotary lobe pump have a long service life; The friction between the rotor and stator of the progressive cavity pump, and the particulate matter in the medium also affect the service life of the wear parts. 3. Different levels of hygiene. Due to the non-streamlined curved surface and numerous defects in the chamber, the progressive cavity pump cannot be a sanitary pump.

Damage to the chamber wall PTFE or rubber is more likely to contaminate the conveying medium. Due to the streamlined structure of the rotor and the fact that there are basically no dead spots and non-metallic parts in the rotor chamber, the rotary lobe pump is more suitable for application in industries with high health requirements such as food and beverage, medicine, etc., especially in the production line automation of the current type is getting higher and higher, and more and more first-class cleaning is used, which shows the importance of choosing a lobe rotary lobe pump. Therefore, the hygienic level of rotary lobe pump is higher than that of progressive cavity pump.

4. The conveying direction is different. The rotary lobe pump can be reversed, and the pump is a completely symmetrical structure; The progressive cavity pump cannot be reversed, and the seal is under pressure when it is conveyed in the opposite direction. 5. The self-priming ability is different.

The screw pump has a good self-priming ability, but it is necessary to avoid idling of the pump body and cannot exceed 30 seconds; Then the rotary lobe pump can produce good self-priming capacity when the speed is greater than 200rpm.