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Analysis of Four System Flow of Screw Air Compressor
Classification: Principles of Engineering
Classification: Service process
Classification: Technical Data
Time：2017-09-27 09:01
After the 1. air process gas is filtered by the air filter to remove dust, it enters the head through the intake valve to be compressed and mixed with lubricating oil. The compressed air mixed with oil is discharged to the oil-gas separation barrel, and then enters the gas pipe network after passing through the oil-gas separator, pressure maintenance valve and aftercooler. 2. lubricating oil process 1. As the pressure in the oil and gas barrel is higher than that in the air intake chamber of the machine head, the lubricating oil passes through the temperature control valve, oil cooler and oil filter under the drive of differential pressure, and then enters the machine head in two ways. One way is directly injected into the compression chamber, the other way passes through the bearing group and then enters the compression chamber, where it is mixed with air and discharged into the oil and gas barrel.
1. air flow
After the gas is filtered by the air filter, it enters the head through the intake valve to be compressed and mixed with lubricating oil. The compressed air mixed with oil is discharged to the oil-gas separation barrel, and then enters the gas pipe network after passing through the oil-gas separator, pressure maintenance valve and aftercooler.
2. lubricating oil flow
1. As the pressure in the oil and gas barrel is higher than that in the air intake chamber of the machine head, the lubricating oil passes through the temperature control valve, the oil cooler and the oil filter under the drive of the pressure difference, and then enters the machine head in two ways. One way is directly injected into the compression chamber, and the other way enters the compression chamber after passing through the bearing group, and is mixed with air in the compression chamber and discharged into the oil and gas barrel. Most of the oil is deposited in the lower part of the oil and gas barrel after coarse separation, and a small amount of oil mist is deposited at the bottom of the filter after passing through the oil and gas separation filter element, and then is introduced into the air intake cavity of the machine head by the oil return pipe.
2. In addition to lubricating oil in the machine head, it also plays a role of cooling and sealing. The heat capacity of lubricating oil is relatively large, and the heat required for each increase is far greater than that of air. The energy input to the head of the drive machine will be converted into heat. In order to control the temperature rise, lubricating oil is sprayed into the head and most of the heat is absorbed by the lubricating oil. Lubricating oil in the head of the fog state distribution, and the air contact area is very large, so the heat transfer is very quickly improved. There is a long gap between the rotor and the casing. The leakage through the gap not only reduces the flow, but also causes high temperature, high energy consumption and high noise. The oil film formed by the lubricating oil between the relative moving parts has an excellent sealing effect, which can effectively prevent the leakage of high-pressure gas to the low-pressure side.
3. control system
1. The role of the control system
A. Automatically adjust the compressor displacement to keep the pressure of the gas tank within the set range.
B. In the computer temperature control system, the fan motor is automatically stopped and started to keep the head exhaust temperature within the set range.
C, in the case of over-temperature, over-pressure, over-current alarm or shutdown.
D, in the boot and shut down according to the set timing of the electrical components.
2. The control system is composed of detection components, analysis components, execution components and man-machine interface. Detection components include temperature sensors (or temperature switches), pressure transmitters (or pressure switches), differential pressure switches, etc.; analysis components are mainly PLC (computer boards); actuators include loading solenoid valves, venting solenoid valves, and contactors; The man-machine interface is mainly liquid crystal displays, buttons and signal lights.
4. drive system
According to the different transmission modes, screw compressors are divided into direct compressor, belt drive compressor and gear drive compressor.
The transmission mode has a significant impact on the energy consumption, operation economy and reliability of the screw compressor. The source of the machine head has an important influence on the transmission mode of the machine.
1. Direct connection compressor
The direct-coupled compressor transmits the power of the motor to the head through the elastic coupling. The transmission link of the direct-coupled compressor consumes almost no energy and is the most efficient transmission mode. There is no maintenance work on the coupling other than replacing the elastomer every 3 years. Using a new type of flange type elastic coupling, the replacement of elastic body is very convenient, no need to disassemble the head, pipeline and valve. The speed of the male rotor of the direct connection compressor is equal to the speed of the motor, so the speed of the direct connection screw compressor is relatively low, and the life and reliability are the highest.
2. Belt drive compressor
The belt drive has the functions of transmitting power and changing the speed. The belt drive relies on friction to transmit power, and it needs to consume a certain amount of energy, accounting for about 2% to 3% of the transmitted power. The belt must have a certain tension to obtain sufficient friction. The belt tension makes the bearings of the motor and the head bear additional radial load. The belt drive compressor has higher requirements on the bearings of the motor and the head. Belt-driven compressors have low production costs and are generally only used for small compressors and economical compressors. Insufficient belt tension will cause the belt to slip and insufficient transmission power, which will not only cause high temperature wear of the belt, but also cause the compressor speed to decrease and reduce the displacement. It is necessary to check the belt tension frequently, pull the belt closer or replace the belt in time. The belts must be replaced in groups.
3. Gear drive compressor
Gear transmission also has the function of transmitting power and changing the speed. Gear transmission itself also needs to consume a certain amount of energy, but it is more efficient than belt transmission. Gear transmission requires additional bearings and higher requirements for the lubrication system of the machine. Because the gear of the screw compressor is a high-speed and heavy-duty gear, the requirements for processing accuracy and material are very high, and the production cost is high. Gear transmission has two main advantages: The first product is easier to modify. By changing the gear ratio to change the head speed, the same head can be used to produce machines with different exhaust volumes. Secondly, there are no consumables and wearing parts in the transmission link of the gear drive compressor.
4. Composite drive compressor
The invention relates to a direct-coupled transmission compressor with an internal speed-increasing gear. The external coupling is used to transmit power, and the internal gear is used to change the speed.