Improvement of control circuit of ML-250 air compressor cooling system
Improvement of Control Circuit of -250 Air Compressor Cooling System Zhao Jianguo\He Shixin2, Liu Linjiang1 (1. Baotou Steel Group Barrun Mining Co., Ltd., Baotou, Inner Mongolia 014080; 2. Baotou Steel (Group) Company Baiyun Ebo Iron Mine, Baotou, Inner Mongolia 014080, China The problem is to improve the control system of the cooling system, in order to eliminate the safety hazard at startup and ensure the safety of the operators. Baotou Steel Group Barrun Mining Co., Ltd. is located in Dalhan Maoming United Banner, Inner Mongolia, and belongs to China's extra-large metal mine. The main perforating equipment of the company is KY-310B roller rig and medium steel weighting produced by Nanchang Kama Company. The YZ-55B roller rig is produced. At present, there are 10 main air compressor systems for the 14 types of roller cone rigs in use, which are Ingersoll Rand ML-250 oil-injected screw compressors. The main air compressor provides compression for the slag discharge of the roller rig and is an important component of the roller rig. The external environment will have a major impact on the normal operation of the air compressor, especially the temperature effect. 1 Air compressor structure and its oil cooling system principle 1.1 Air compressor composition Ingersoll Rand ML-250 fuel injection screw air compressor from the main engine and motor system, lubrication and cooling system, pneumatic system, oil and gas separation system, control system And the composition of the protection system. The main air compressor system of the roller rig used by Barrun uses SEINTELLISYS controller, which can accurately control the compressor discharge pressure, exhaust temperature, pre-separation pressure and overheating of the fan and main unit of the electric control system, -) , Wulanchabu City, Inner Mongolia, an assistant engineer, is now engaged in equipment inspection. ML-250 air compressor cooling system control circuit improves overcurrent protection and other functions. The main body of the compressor has a pair of male and female rotors that mesh with each other. The motor directly drives the male rotor through the gear to drive the female rotor to rotate. The injected oil mixes with the air and is effectively compressed between the rotor slots. Lubricating oil forms an oil film between the rotor slots, acts as a seal gap and lubricates the rotor, and mixes with the air to remove most of the heat generated by air compression. 1.2 Oil circuit principle When the compressor is running, the high temperature and high pressure air mixed with a large amount of oil mist is discharged into the oil separator by the compressor. Most of the oil droplets in the air settle due to the rotation, collision and direction change of the air flow in the separator. The bottom of the container. Under the action of high pressure in the separator, the lubricating oil flows along the return pipe to the temperature control valve; the different opening angles of the temperature control valve cause part or all of the lubricating oil to flow through the oil cooler, and the temperature controlled lubricating oil flows through the oil under constant pressure. Filter, oil-discharge solenoid valve is injected into the compressor screw rotor cavity and each bearing. 0. In the system, the lubricating oil circulation depends on the pressure difference between the oil separator and the main engine fuel injection port and bearing, and the oil circulation The principle is as shown. Oil circulation principle The improvement of the air compressor start-up mode is the high season of the air compressor failure of the roller rig. Especially the Barrun Mining Company is located in the plateau, which belongs to the high-cold area. The winter is very cold and the average temperature is -25*C. It can reach -38*C. The ambient temperature is too low. When the oil in the air compressor cylinder is cooled by the temperature control valve to the oil radiator, the temperature control valve cannot be opened in time, and the oil viscosity is enhanced due to the low oil temperature. The fan motor is designed to start at the same time as the main engine, so that the temperature of the oil entering the radiator is lower, the viscosity is larger, and the oil circulation is not smooth, resulting in high temperature alarm of the host; after the hole is finished, during the moving process, due to the air compressor In the unloading state, the oil pressure is low, the oil circulation speed is reduced, and under the action of the cooling fan, the oil circulation is again caused to be poor, and the high temperature alarm is issued. In view of the above phenomenon, we improved the starting mode of the ML-250 fuel injection screw air compressor. When the air compressor starts, the fan motor switch is turned off first. After the temperature control valve is completely opened, the oil in the pipeline is circulated through the cooler. Then turn on the fan; after each hole is finished, when the air compressor is in the unloading state, turn off the fan motor switch. By thus improving the starting method of the air compressor, the equipment downtime caused by the high temperature alarm of the air compressor under the low temperature environment is significantly shortened, and the equipment operation efficiency is greatly improved. The improved startup mode operator needs to frequently turn on and off the fan motor switch, and the original design fan motor switch is placed in the main air compressor control cabinet, the personnel operation is unchanged and the arc burn and electric shock are prone to occur during operation. Therefore, we have improved the original cooling system control circuit to make it more suitable for the startup mode in the cold environment, and to eliminate the safety hazards during personnel operation. 3 cooling system control circuit improvement cooling system fan motor control circuit is mainly composed of protective air switch MMS, fan contactor KM4, fan overload relay FOL, etc., as shown, and INTELLISYS controls the various working modes of the air compressor, Monitor critical operating parameters and stop the machine from running when it encounters a problem. Press the start button to send a signal to INTELLISYS, INTELLISYS will turn on the starter coil, the air compressor starts, when the star triangle conversion is completed, the KM4 coil is energized, the main contact is closed, and the fan motor control circuit is turned on; When the fan motor is overloaded, the FOL normally open contact closes and the INTELLI-SYS alarm stops. Baogang Technology improved cooling system control schematic diagram improved control circuit as shown, on the basis of keeping the original control circuit unchanged, add contactor KM5, start button SB1 and stop button SB2, SB1, SB2 can be installed in the control cabinet On the outside or on the driver's cab, it is convenient for the operator to control the connection and disconnection safely and conveniently. 4 Conclusion The improved cooling system control circuit is better adapted to the startup mode of the ML-250 fuel injection screw air compressor in the cold environment, ensuring the normal use of this type of air compressor in the northern winter. However, such an improvement has an increase in hardware equipment, still requires manual operation, and is inefficient. It is also necessary to start from the INTELLISS controller, by modifying the control program, increasing the control mode under cold conditions, and starting the appropriate delay by the fan start and the host, so that the air compressor can be used normally in a cold environment. Rice Mill,Rice Mill Machine,Rice Grinder Machine,Small Rice Milling Machine Hunan Nongyou Machinery Group CO.,LTD , https://www.ricemill.nl