Differences and characteristics of single screw pumps, twin screw pumps, and triple screw pumps

Progressing cavity pumps, twin screw pumps and triple screw pumps all belong to the category of progressing cavity pumps, and their differences and characteristics are as follows:

Progressing cavity pumps. A progressing cavity pump consists of a cylindrical housing with a screw and an internal rotor. While the pump is running, the screw rotates and draws the medium from the suction end into the pump, then compresses the medium and pushes it towards the outlet end.

The progressing cavity pump has a simple structure and easy maintenance, but the pressure and flow rate are small, and it is suitable for conveying media with low viscosity.

Twin screw pumps. A twin screw pump consists of two intermeshing screws and housings. Compared to progressing cavity pumps, twin progressing cavity pumps are able to provide higher pressures and flow rates, and the consistency of the conveyed medium can be higher. Twin screw pumps also reduce leakage in the pump and increase pump efficiency.

Triple progressive cavity pump. The three-screw pump is composed of three screws and a housing. The advantages of the triple progressive cavity pump are higher pressures and flow rates, and it is suitable for conveying higher consistencies such as those with high temperatures, high viscosity and high solids content.

The three-screw pump is also characterized by stable flow and low noise.

In short, single-screw pumps, twin-screw pumps and three-screw pumps have their own characteristics, and the appropriate pump type should be selected according to the specific use requirements and media characteristics.

A progressing cavity pump is the simplest type of progressive cavity pump that consists of a screw and a housing. It is characterized by simple structure, small size, light weight, low cost, and is suitable for conveying liquids with low viscosity, low pressure and no solid particles. However, the flow rate of the progressing cavity pump is unstable and the pressure fluctuation is large, which is not suitable for conveying special liquids such as high viscosity, high pressure, easy crystallization, volatile and corrosion.

A twin progressive cavity pump consists of two intermeshing screws and a housing. It is characterized by stable flow rate, small pressure pulsation, and is suitable for conveying special liquids such as high viscosity, high pressure, easy crystallization, volatile, and easy corrosion. Twin screw pumps also have self-priming capacity and high efficiency, but they are higher and more complex to maintain.

The three-progressive cavity pump consists of three intermeshing screws and a housing. It is characterized by stable flow and minimal pressure fluctuation, and is suitable for conveying special liquids such as high viscosity, high pressure, easy crystallization, volatile, and corrosion. Triple progressive cavity pumps also have self-priming capacity, high efficiency and low noise, but they are the most complex to maintain.

Screw pump is a rotary pump that relies on the meshing space formed by the pump body and screw to change and move to transport liquid or pressurize it. Screw pumps are divided into single screw pumps, twin screw pumps and triple screw pumps according to the number of screws. Its main working parts are the screw (called the rotor) of the eccentric spiral and the screw bushing (called the stator) with a double helix surface on the inner surface.

The triple screw pump is a positive displacement pump, which is widely used in conveying high viscosity, easy to coagulate, volatile, corrosive liquids, high-temperature liquids, and liquids containing solid particles and fibers. When selecting a model, the following aspects need to be considered:

Flow rate and head: According to the flow rate and head requirements of the conveyed liquid, select the appropriate three-screw pump model. Normally, the flow rate of the three-comma screw pump is proportional to the rotational speed, and the head is proportional to the square of the rotational speed.

Viscosity: Triple screw pumps are suitable for conveying high viscosity liquids, but different types of triple screw pumps are suitable for different viscosity ranges. It is necessary to choose the appropriate model according to the specific situation.

Temperature: The temperature range of the three-screw pump is related to the sealing material and the pump body material, and it is necessary to choose the appropriate model according to the temperature of the liquid.

Pressure: The pressure of a three-screw pump is related to the number of stages and diameter of the pump. In general, the pressure range of the three-screw pump is between.

Special requirements: If the liquid being conveyed has special requirements, such as containing solid particles and fibers, it is necessary to choose a three-screw pump model that can meet the requirements.

In short, when choosing a three-screw pump, it is necessary to choose the appropriate model according to the specific requirements of the conveyed liquid and the conditions of use. At the same time, it is also necessary to consider its performance, reliability, ease of maintenance and other factors.

The following aspects need to be considered in the selection of the brigade-resistant three-screw pump:

1.Flow rate: The flow rate of the pump is determined according to the flow demand of the liquid being transported, and the pump is generally slightly larger than the actual flow rate.

2.Head: According to the conveying distance and conveying height of the conveyed liquid, the head of the pump is determined, and the pump is generally slightly larger than the actual head.

3.Temperature: Determine the material and sealing form of the pump according to the temperature of the conveyed liquid to ensure the normal operation of the pump.

4.Viscosity: Determine the speed of the pump and the shape of the screw according to the viscosity of the conveyed liquid to ensure the normal operation of the pump.

5.Special requirements: According to the special requirements of the conveyed liquid, such as containing solid particles, easy to crystallize, volatile, easy to corrode, etc., select the corresponding pump material and structure.

Considering the above factors, select the appropriate three-screw pump model and specifications. At the same time, it is also necessary to consider factors such as the reliability of the pump, ease of maintenance, and **.

Progressive cavity pumps can be mainly divided into the following types:

Progressing cavity pump (also known as progressing cavity rotary lobe pump or mono pump): A progressing cavity pump consists of a rotor in the shape of a screw and a stator with internal threads. The rotor is usually made of stainless steel, and the stator is usually made of an elastic material.

The progressing cavity pump has the characteristics of simple structure, stable operation, low noise and convenient maintenance, and is suitable for conveying media with high viscosity, solid particles, and easy to precipitate or crystallize.

Twin screw pumps: Twin screw pumps consist of two screws that mesh with each other and rotate in the same direction. The twin screw pump has high conveying efficiency and low pulsation, and is suitable for conveying liquids, gases, liquids and liquid-solid mixtures with high viscosity.

There are usually two types of twin screw pumps: non-self-priming twin screw pumps and acre wheel self-priming twin screw pumps.

Triple screw pump: The triple screw pump consists of three screws that mesh with each other and rotate in the same direction. Among them, one is the main screw and the other is the slave screw.

The three-screw pump is mainly used to transport liquids with good lubrication, such as lubricating oil and fuel, and has the characteristics of high pressure bearing capacity, low noise and high efficiency.

Multi-screw pumps: Multi-screw pumps typically consist of four or more screws to meet specific application needs. The multi-screw pump can be customized as required with high conveying efficiency and low pulsation.

Mixed Flow Progressive Cavity Pump: A mixed flow progressive cavity pump is a pump that combines the characteristics of a progressive cavity pump and a centrifugal pump. It has the self-priming capacity of a progressive cavity pump and the high head of a centrifugal pump, which is suitable for conveying highly viscous media and liquids containing gases.

Each of these progressive cavity pumps has its own characteristics and is suitable for different working conditions and application scenarios. When selecting a progressive cavity pump, the appropriate type should be determined according to the specific conveying medium, working condition requirements and use scenarios.

A progressive cavity pump is a common positive displacement pump that consists of two or more screws that mesh with each other. According to factors such as the structure, use and application scenarios of the screw, the screw pump can be divided into the following types:

1.Progressing cavity pumps: Progressing cavity pumps, also known as screw extrusion pumps, consist of a screw and generally an internally eroded housing. It is mainly used to convey low viscosity liquids.

2.Twin screw pumps: Twin screw pumps consist of two intermeshing screws and a casing that is generally a solid rotor inside and outside. It is mainly used to convey high viscosity liquids.

3.Triple Progressive Cavity Pump: The triple progressive cavity pump consists of three screws meshing Acer and the outer and outer solid rotor housings. It is mainly used for conveying high-temperature, high-viscosity and flammable and explosive media.

4.Four-screw pump: The four-screw pump consists of four intermeshing screws and the housing of the inner and outer solid rotor. It is mainly used to convey high-temperature, high-viscosity and flammable and explosive media, and has higher output and higher pressure.

Overall, the performance and purpose of progressive cavity pumps vary depending on factors such as screw shape, bore diameter, speed, displacement and pitch. Therefore, choosing the right progressive cavity pump type is a key factor in ensuring optimal performance and long-term operational stability.

A progressive cavity pump is a fluid transfer pump, which is mainly composed of a screw (generally there are types such as single-head screw, double-head screw and three-head screw) and a pump casing. It utilizes the meshing between the screws to create a closed cavity to transfer fluids. Screw pumps are widely used in petroleum, chemical, food, pharmaceutical and other fields.

Here are some of the main features of progressive cavity pumps:

Stable conveying capacity: The screw pump has good conveying capacity, and the output flow of the pump is proportional to the speed of the screw, which can achieve continuous and stable conveying.

Strong self-priming performance: Progressive cavity pumps have a strong self-priming capacity, so they have an advantage when pumping liquids with gases or containing foam.

Smooth operation: the screw pump runs smoothly, with low vibration and low noise. These features make it suitable for high precision and demanding applications.

Wide adaptability: Progressive cavity pumps can convey various types of fluids, including high viscosity, high solids, high gas content, corrosive and abrasive fluids, with high adaptability.

Simple structure: The progressive cavity pump has a simple and compact structure, which is easy to install and maintain.

High efficiency and energy saving: Due to the structural characteristics of the progressive cavity pump, the energy loss in the conveying process is small, and it has high energy efficiency.

Reversibility: The progressive cavity pump can reverse the direction of the conveying flow by changing the screw steering, which makes it advantageous in some special application scenarios.

It is important to note that although progressive cavity pumps have many advantages, they still need to be evaluated according to the actual application and fluid characteristics when choosing to ensure that the right pump type is selected.

1. The screw sealing line formed by the contact between the stator and the rotor of the screw pump separates the suction chamber from the discharge chamber (pressure chamber)*, so that the pump has the isolation effect of the valve.

2. Compared with other forms of pumps, the screw pump has a higher suction capacity (up to meters).

3. The screw pump can realize the multi-phase mixed transportation of liquid, gas and solid.

4. The volume of fluid flow in the screw pump does not change, and there is no turbulence, agitation and pulsation.

5. The viscosity of the medium conveyed by the screw pump can reach 3,000,000MPas, and the solid content can reach 60%.

6. The volume formed by the elastic stator of the progressive cavity pump can effectively reduce the wear and tear of the medium containing solid particles.

7. The flow rate of the screw pump is proportional to the speed, and the flow rate can be automatically adjusted with the help of the governor.

8. Constant pressure control of screw pump, protection against dry operation.

It is widely used in petroleum, chemical fiber, metallurgy, machinery, electric power, machine tools, ships, glass, highways and other industries.

It is suitable for conveying liquids of various viscosities, especially viscous and difficult-to-convey media. Liquids of various concentrations and dry materials that have been separated and dewatered. Liquids containing solid particles, fibers, suspended solids.

Mixtures of liquids, gases, solids. Sensitive liquids that cannot be stirred, sheared, or plundered. Corrosive liquids.

There are two types of twin screw pumps, sealed and unsealed, according to the medium from one end or from both ends into the meshing space, the twin screw is divided into two types of structures: double suction type and single suction type.

A twin progressive cavity pump is an externally meshing progressive cavity pump that uses two screws that mesh with each other and do not touch each other to pump liquids.

The twin screw pump is a double-suction non-enclosed twin screw pump. The active screw, which extends out of the pump at one end, is driven by the prime mover. The driving screw and the driven screw have threads with different rotation directions.

The screw fits snugly into the pump body. The driven screw is driven by the driving screw by means of a synchronous gear.

As a positive displacement pump, the suction chamber in the pump should be closely separated from the discharge chamber. Therefore, the outer surface of the pump body and the screw and the gap between the screw and the screw should be as small as possible. At the same time, the screw and the pump body, and between the screw and the screw form a sealing cavity to ensure that it is sealed, otherwise there may be liquid backflow back from the gap.

Twin screw pumps can be divided into two forms: built-in bearings and external bearings. In the type with built-in bearings, the bearings are lubricated by conveyed material. The working chamber of the twin screw pump with external bearing structure is separated from the bearing.

Due to the structure of this pump and the side clearance that exists between the screws, it can convey non-lubricating media. In addition, the timing gear is adjusted so that the screw does not touch, while transmitting half of the output torque to the driven screw. As with all progressive cavity pumps, the externally bearing twin screw pumps are self-priming, and most of the pump conveying elements themselves are arranged symmetrically with double suction to eliminate axial forces and also have a large suction height.

Twin screw pump series products are divided into two categories: single suction twin screw pump and double suction twin screw pump. This series of products has a special screw profile and a special structure supporting it, which is widely used in petroleum, chemical, metallurgy, steel, electric power, shipbuilding, pharmaceutical, food, building materials and other industries. These characteristics also make this series of pumps have potential development prospects.

Fig. 1 shows an unsealed double-suction twin screw pump. Its pump body is equipped with two screws that are left and have a single-head thread, and when the driving screw 2 is driven to rotate by the power machine, the driven screw 3 is driven to rotate by the synchronous gear 1. Two screws and a screw and pump body.

There is a gap between them, which is guaranteed by gears and bearings. The size of the gap depends on the viscosity of the liquid, the working pressure and other factors. Since the threads at both ends of each screw are rotated in opposite directions, the pump working chamber formed by the screw meshing line when the screw rotates.