Geared compressor is a type of air compressor that compresses air by centrifugal force generated by multiple impellers driven by gears. This post will introduce its working principle, applications, advantages, and differences with centrifugal compressor.

What is a geared compressor?

Structure of integrally geared compressor

The structure of a geared compressor is similar to turbo compressor, usually includes a three-axis integral gear design, an impeller structure, a bearing structure, and an air seal and oil seal structure. The specifics are as follows:

Three-shaft integral gear design: This structural design makes the compressor compact and easy to maintain, and has high performance. The three-shaft integral gear oil-free compressor is a common type of geared compressor.

Impeller: The impeller is the core component of the centrifugal geared compressor. It works on the gas through the rotation of the impeller, increases the flow rate of the gas, and converts its kinetic energy into pressure energy.

Bearing: The design of the bearing structure is crucial to ensure the stable operation of the geared compressor. In oil-free geared compressors, the optimization of the bearing structure can reduce friction and extend the service life of the equipment.

Gas seal and oil seal: The optimized design of gas seal and oil seal structure can realize oil and gas separation in the air compression process of geared compressor, and provide compressed air with higher cleanliness. This is especially important for industrial production occasions with high requirements for compressed air quality.

The structural design of geared compressors focuses on efficiency and reliability. It has the characteristics of simple structure, smooth operation, low noise and low maintenance cost. and meets the industrial demand for high-performance compressed air through precise mechanical design.

When selecting a geared compressor, you should consider whether its structural characteristics meet specific application requirements, such as whether oil-free lubrication is required, the cleanliness requirements of compressed air, etc.

Working principle of integrally geared compressor

There are multiple impellers in the geared compressor that are driven by gears to rotate, and each gear can be controlled independently. During operation, the motor drives the gears to rotate, the intake valve opens, and the gas enters the cylinder.

As the impeller rotates, the gas is compressed until the pressure in the cylinder reaches the pressure at which the exhaust valve opens. At this time, the exhaust valve opens and the compressed gas is discharged from the cylinder.

The principle of the geared compressor is simple and effective, and its reliability and efficiency make it the first choice in many application scenarios.

Advantages of geared compressor

The principle of the geared compressor has many advantages. First, due to its simple structure and convenient maintenance, it has high reliability in long-term use and is very easy to maintain. Secondly, due to its unique working principle, the geared compressor is very efficient and can effectively reduce energy consumption. Finally, its low noise and low impact on the environment make it an ideal choice in many scenarios.

Applications of geared compressor

Gear compressors are widely used in many fields due to their high efficiency, durability and easy maintenance. In industrial production, geared compressors are widely used in steel, chemical, food processing, textile and other fields.

According to air compressor market in oil and gas industry, geared compressors are also widely used in the field of natural gas transportation. In this field, it is usually used as a key link in the pipeline transportation process. Its high efficiency and energy saving, reliability and low maintenance cost are one of the reasons why geared compressors are favored in natural gas transportation.

Gear compressors are also widely used in the field of hydraulic systems. By using geared compressors for compression and delivery of hydraulic pumps, hydraulic systems can achieve efficient energy consumption and cost control, while also improving production efficiency and product quality. In this field, geared compressors can provide users with a variety of power and flow options.

In refrigeration and air-conditioning equipment, geared compressors are widely used in various occasions requiring refrigeration and gas compression due to their high efficiency and low noise, such as providing refrigerant circulation for air conditioners, cold storage, etc.

In addition, geared compressors are also widely used in industrial production and laboratory research, such as vacuum technology, pressure regulation and gas transmission. geared compressors can also achieve higher power and higher compression ratios by using multiple two-stage integrally geared compressors in series.

The difference between gear pump and geared compressor

Definition

A gear pump is a mechanical hydraulic pump that generates hydraulic energy through the rotation of a pair of gears and can be used to transport liquids such as water and fuel. A geared compressor is a mechanical compressor that uses the movement of rotating gears to compress gas and can be used to produce gases such as air and nitrogen.

Working Principle

The gear pump consists of gears and a pump body. The gears rotate inside the pump body, and the funnel-shaped pump body compresses the liquid and delivers it to the pump port. The working principle of the geared compressor is similar, using the rotation of the gears to increase the volume of the compression chamber, thereby compressing the gas.

Application fields

Gear pumps are widely used in industrial and agricultural fields, such as machine tool lubrication, hydraulic systems, generator sets, etc. Geared compressors are mainly used in the field of gas propulsion, such as the manufacture of compressed air and gas-liquid mixtures, as well as the production of gas springs and hydraulic cylinders.

Gear pumps and geared compressors are essentially different in their working principles and application areas. One is mainly used to transport liquids, and the other is mainly used to compress gases.

In addition, there are also differences in their structures. Gear pumps usually consist of two meshing gears and a pump body, while geared compressors include a compression chamber and rotating impellers.

Types of centrifugal compressors

There are many specifications of centrifugal compressors, and the structures of centrifugal compressors can be divided into three categories, which are called integrally geared type, single shaft type, prime mover and combined structure.

(KOA Series Centrifugal Air Compressor)

Integrally geared centrifugal compressor

Ordinary integrally geared centrifugal compressor

Ordinary integrally geared centrifugal compressors can be used in many places, such as air, nitrogen and other gases. If they want to be compressed and put into some equipment, they must be used with integrally geared compressors. Its characteristics are high efficiency and compact structure.

In the past, geared compressors could basically only be used for ordinary gas compression. Now, integrally geared compressors can be used in a variety of gas compression and are more widely used. The most important feature of geared compressors is that installation, repair and maintenance are more convenient and faster than other compressors, which greatly shortens the delivery time.

Industrial integrally geared centrifugal compressor

The industrial integrally geared centrifugal compressors in some functions have greatly exceeded those of single-shaft compressors. For decades, compressor manufacturers have continuously improved the deficiencies of integrally geared compressors in terms of technology. The upgrades it has shown have made great progress in the compression of process gases.

It reduces the toxic, flammable, explosive and highly corrosive gases contained in process gases so that they no longer leak. The compression equipment for various gases such as oxygen and natural gas are basically integrally geared compressors; the first launch of dry gas seals has further confirmed that integrally geared compressors are no longer limited to single occasions.

Single shaft centrifugal compressor

Horizontal split compressor

Horizontal split centrifugal compressors mainly have corresponding requirements for air pressure, requiring the exhaust air pressure to be between 4 and 5 MPa. The structural feature of horizontal split centrifugal compressors is that the casing, partitions and other parts are divided into upper and lower parts.

For gases with smaller molecular weight, this type of compressor is difficult to play a role and is basically unusable. However, horizontal split compressors also have advantages that other compressors cannot match, mainly because they are extremely simple to disassemble and assemble.

(Horizontal split centrifugal compressor structure)

Vertically split compressor

Vertically split centrifugal compressor has another name, it is called “barrel compressor”. Barrel compressor is almost perfect in some places, but it also has disadvantages. Barrel compressor is difficult to disassemble and install, which makes it more complicated to maintain and repair.

Therefore, most of the barrel compressors are used by manufacturers in places that require high pressure and tight sealing.

Prime movers and centrifugal compressors

Combining the compressor and the prime mover is the main topic that all kinds of compressor manufacturers are discussing now. They have also made great breakthroughs in the combination methods, such as the structural form of the combination of expander and compressor, the structural form of composite assembled compressor, and the structural form of the combination of electric motor and compressor.

These combinations are important combinations of prime movers and centrifugal compressors. Through the combination, the structure and production method of the compressor have undergone tremendous changes, which mainly act on the sealing system to omit the shaft end and reduce its footprint. The workload of its maintenance is also optimized and reduced.

How does a centrifugal compressor work?

The working principle of centrifugal compressor is based on kinetic energy conversion and gas dynamics, and specifically includes the following steps:

1. Gas suction: When the integrally geared centrifugal compressor is working, air or other gases enter the suction chamber axially through the suction port.
2. Impeller acceleration: The gas enters the high-speed rotating working wheel (impeller) evenly under the guidance of the suction chamber. The impeller, also known as the working wheel, is an important component of the centrifugal compressor.
3. Kinetic energy conversion: Under the high-speed rotation of the impeller, the gas gains kinetic energy. Due to the centrifugal force, the gas is accelerated in the blade groove and thrown outward.
4. Diffusion flow: The high-speed gas flowing out of the impeller enters the diffuser, which partially converts the kinetic energy of the gas into pressure energy, further increasing the pressure of the gas.
5. Gas guidance: The gas after diffusing is collected in the volute, and then guided to the inter-cooler or condenser through the exhaust port.

6. Multi-stage compression: For situations where higher pressure is required, the compressor may use multi-stage compression, single stage air compressor vs 2 stage has lower pressure output. That is, the gas after the first stage of compression enters the next stage of impeller for further compression, and the pressure is increased step by step.
7. Inter-cooling: In the multi-stage compression process, in order to improve efficiency, an inter-cooler is usually set between each compression stage to reduce the gas temperature and reduce the compression power consumption.
8. Continuous compression: Centrifugal compressors can continuously inhale fresh gas and discharge compressed gas to achieve continuous production of compressed air or other gases.
9. Oil-free compression: In some applications, such as food, pharmaceutical or electronics industries, centrifugal compressors can be designed as oil-free compressors to ensure the purity of compressed air.
10. Efficiency and energy efficiency: The efficiency of centrifugal compressors is generally high, but it will be affected by mechanical losses and gas friction. The energy efficiency of the compressor can be improved by optimizing the design and operation.

Centrifugal compressors are widely used in industrial fields such as air compression, chemical processes, oil and gas processing, etc., and are favored for their high efficiency, large flow and reliability.

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