1、 Air flow
After the dust is filtered by the air filter, the gas enters the machine head through the air inlet valve and is compressed and mixed with the lubricating oil. The compressed air mixed with oil is discharged to the oil gas separation drum, and then enters the gas pipe network through the oil gas separator, pressure maintaining valve and aftercooler.
2、 Lube oil flow
1. As the pressure in the oil and gas barrel is higher than that in the air inlet chamber of the head, the lubricating oil is driven by the differential pressure through the temperature control valve, oil cooler and oil filter, and then enters the head in two ways, one way is directly injected into the compression chamber, the other way is through the bearing group and then enters the compression chamber, where it is mixed with air 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 rough separation, and a small amount of oil mist is deposited at the bottom of the filter element after passing through the oil and gas separation filter element, and then is introduced into the air inlet chamber of the machine head by the oil return pipe.
2. In addition to lubrication, lubricating oil also plays a cooling and sealing role in the machine head. The heat capacity of lubricating oil is relatively large, and the heat required for each degree of increase is far greater than that of air. The energy input from the drive machine to the machine head will be converted into heat. In order to control the temperature rise, lubricating oil will be injected into the machine head to absorb most of the heat. The lubricating oil is distributed in fog state in the head, and the contact area with air is large, so the heat transfer is very fast and perfect. There is a long clearance between rotors and between rotors and casings. Leakage through the clearance will not only reduce flow, but also lead to high temperature, high energy consumption and high noise. The oil film formed by lubricating oil between relative moving parts has excellent sealing effect, which can effectively prevent the leakage of high-pressure gas to the low-pressure side.
3、 Control system
1. Function of control system
A. Automatically adjust the air discharge of the compressor to keep the pressure of the air tank within the set range.
B. In the computer temperature regulating system, the fan motor is automatically stopped and started to keep the exhaust temperature of the machine head within the set range.
C. Alarm or shutdown in case of overtemperature, overvoltage, overcurrent, etc.
D. During startup and shutdown, start and close all electrical components according to the set time sequence.
2. The control system is composed of detection elements, analysis elements, executive elements and human-computer interface. Detection elements include temperature sensor (or temperature switch), pressure transmitter (or pressure switch), differential pressure switch, etc; The analysis element is mainly PLC (computer board); The actuating elements include loading solenoid valve, venting solenoid valve and contactor; The human-computer interface mainly includes LCD, buttons and signal lights.
4、 Drive system
According to different transmission modes, screw compressors are divided into direct compressor, belt driven compressor and gear driven compressor.
The transmission mode has a significant impact on the energy consumption, economic operation 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 compressor
The direct coupled compressor transmits the motor power 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 other maintenance work for the coupling except that the elastic body is replaced every 3 years. The new flange type elastic coupling is adopted, which is very convenient to replace the elastomer without dismantling the machine head, pipeline and valve. The male rotor speed of the direct coupled compressor is equal to the motor speed, so the speed of the direct coupled screw compressor is relatively low, with the highest service life and reliability.
2. Belt driven compressor
The belt transmission has the function of transmitting power and changing speed. The belt transmission relies on friction to transmit power, which consumes a certain amount of energy, accounting for 2%~3% of the transmission 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 driven compressor has higher requirements on the bearings of the motor and the head. Belt driven compressor has low production cost and is generally only used for small compressors and economical compressors. Insufficient belt tension will cause belt slipping and insufficient power transmission, which will not only cause high temperature wear of the belt, but also reduce the compressor speed to reduce the exhaust volume. The belt tension shall be checked frequently, and the belt shall be tightened or replaced in time. Belts must be replaced in groups.
3. Gear driven compressor
Gear transmission also has the function of transmitting power and changing 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 has higher requirements for the lubrication system of the machine. Because the gear of the screw compressor is a high-speed and heavy load gear, the requirements for machining accuracy and material quality are very high, and the production cost is high. Gear transmission has two main advantages: the first product is easy to be modified. By changing the gear transmission ratio and changing 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 driven compressor.
4. Compound drive compressor
The utility model relates to a direct coupled transmission compressor with an internal speed increasing gear. The coupling is used to transmit power externally, and the gear is used to change the speed internally.