Working principle and relative knowledge of double screw air compressor
Screw type air compressor is a displacement compressor, which is achieved by gradually reducing the volume of work to achieve the purpose of gas compression.
The working capacity of a screw air compressor consists of a pair of rotor teeth that are parallel to each other and are meshed with each other and a housing containing the pair of rotors. When the machine is running two rotor teeth each other and inserted into the other tooth with rotation of the rotor tooth inserted into the other slot to the exhaust volume of the mobile terminal, by the other teeth closed gradually narrowed, the pressure gradually increased, until it reaches the required pressure, the tooth side communicates with the exhaust port, exhaust to achieve.
When the teeth are meshed with each other, the teeth are inserted to form two spaces separated by teeth, and the alveolar teeth near the suction end are inspiratory volume, which is the volume of compressed gas near the exhaust end. With the operation of the compressor, the other rotor tooth insert tooth moved toward the exhaust end of the suction volume expanding, shrinking volume of compressed gas, so as to realize the compression process in each slot suction, when compressed gas in alveolar pressure reaches the required exhaust pressure, the exhaust orifice is communicated with the slot just start the exhaust process. The variation of the suction volume and the compression volume divided by the teeth of the opposing rotor is repeated, so that the compressor can continuously inhale, compress and exhaust air.
The working principle and structure of screw compressor:
1 inspiratory process:
The air inlet side of the screw type suction mouth, must be designed so that the compression chamber can fully inhale, and no screw type air compressor intake and exhaust valve, intake of only one valve opening and closing control, when the rotor rotates, the tooth groove space of main and auxiliary rotor opening in the inlet to the end wall, the the largest space, the free air space and the air inlet of the rotor tooth groove communicated, because in the exhaust air is discharged in full gear, exhaust at the end of the tooth groove is in a vacuum state, when transferred to the air inlet, the outside air is sucked into the tooth grooves along the axial direction, flow into the side of the rotor. The maintenance of the screw type air compressor reminds that when the air is filled with the whole tooth groove, the intake side face of the rotor is turned away from the air inlet of the casing, and the air between the teeth groove is closed.
2, sealing and conveying process:
When the main and auxiliary two rotors are at the end of the suction, the main and auxiliary rotor teeth summit and the casing are closed. At this time, the air is closed in the gear groove and no longer flows out, that is, [sealing process]. The two rotor continues to rotate, and the tooth peak coincides with the tooth groove at the suction end, and the anastomotic surface moves towards the exhaust end gradually.
3, compression and fuel injection process:
In the transportation process, the meshing surface gradually moves towards the exhaust end, that is, the gap between the meshing surface and the exhaust port is gradually reduced, the gas in the groove is gradually compressed, and the pressure is raised, that is, the compression process. While the compression, at the same time, the lubricant is also injected into the compression chamber due to the pressure difference and mixed with the chamber gas.
4. Exhaust process:
When the engagement of screw compressor rotor and casing repair to exhaust the same, (at the highest pressure of compressed gas) gas is compressed the discharge, until the end of tooth meshing surface to exhaust the peaks and the tooth groove, the two rotor meshing surface and the casing outlet the tooth groove space is zero, is completed (at the same time, the exhaust process) the tooth groove length between the rotor and casing inlet mesh and achieve the longest, and in the process of breathing.
Screw compressor is divided into open type, semi closed type and totally enclosed type
Totally enclosed screw compressor:
The body is made of cast iron structure with high quality, low porosity, small thermal deformation; the body adopts a double wall structure, including the exhaust channel, high strength, good noise reduction effect; the inside and outside of the body force balance, no open, semi closed under high risk; the shell is of steel structure, high strength, beautiful appearance, light weight. The vertical structure of compressor, small occupied area, is conducive to water chiller with layout; immersed in the oil bearing groove, good lubrication performance of the bearing rotor; axial force is semi closed and open reduction of 50% (balance the exhaust side of the motor shaft); no risk, high reliability of the motor horizontal cantilever; avoid screw rotor, slide valve the motor rotor, the influence of gravity on the fitting accuracy, improve the reliability of the assembly process is good. No oil pump screw vertical design, so that the compressor running or shutdown will not appear lack of oil. In the oil groove of the lower bearing whole immersion, differential pressure oil supply system of the upper bearing; differential pressure is low, in case of emergency, bearing lubrication protection, avoid bearing lubrication, opening to the transition season set.
Disadvantages: using exhaust cooling, the motor at the exhaust port, easily lead to motor coil burnout; in addition, the failure can not be ruled out in time.
Two, half closed screw compressor
Spray cooling motor motor, low working temperature, long service life; the use of air cooling type motor compressor motor, high working temperature, affect the service life of the motor and working environment in the room is poor; the use of exhaust cooling motor, the motor temperature is high, the service life of the motor is short. Generally, the external oil volume is larger, but the efficiency is very high. The built-in oil and compressor combine together, the volume is small, so the effect is relatively poor. Two grade oil distribution effect of up to 99.999%, in a variety of conditions can ensure that the compressor has a good lubrication.
But piston type semi closed screw compressor through gear transmission, the growth rate, high speed (about 12000 RPM), large wear, poor reliability.
Three 、 open type screw compressor
The advantages of the open type unit are:
1) compressor and motor separation, so that the scope of the compressor wider;
2) the same compressor can be applied to different refrigerants, in addition to using halogenated hydrocarbon refrigerants, by changing parts of the material, ammonia can also be used as refrigerant;
3) according to different refrigerants and working conditions, they are equipped with motors of different capacities.
The main disadvantages of the open type unit are:
(1) the seal is easy to leak, and this is also the object that users often maintain;
(2) the motor is rotating at high speed, the air flow noise is large, and the noise of the compressor itself is larger, which affects the environment;
(3) complex oil system components, such as individual oil separator and oil cooler, need to be configured. The unit is bulky and inconvenient to use and maintain.
