Abstract: This paper introduces the application of UniMAT PLC in the control system of oil and gas lubrication equipment. As a new type of lubrication technology, oil-gas lubrication is also known as gas-liquid two-phase fluid cooling lubrication technology, which uses compressed air as the carrier to transport a uniform, micro continuous oil flow to the lubrication point. Compared with the traditional thin oil lubrication and dry oil lubrication, oil-air lubrication has its incomparable lubrication effect, which greatly prolongs the service life of lubricating parts and reduces environmental pollution. UniMAT PLC is introduced into the oil-gas lubrication equipment as its automatic control core, which realizes the automatic operation of the equipment, precise control of air pressure and hydraulic pressure. The system is stable, reliable, easy to use and flexible to meet the needs of users.
Key words: oil air lubrication, UniMAT PLC, automatic control
1. Introduction
Oil-air lubrication system is a new type of lubrication technology, which is widely used in all walks of life of construction machinery. In recent years, China has accelerated the development and innovation of oil-air lubrication system. The perfect monitoring system and stable operation characteristics have become the key points to measure the excellent oil and gas lubrication equipment.
2. working principle
Oil-air lubrication is a centralized lubrication method, which uses continuous flow of compressed air to produce intermittent supply of thin oil to form swirling liquid droplets and transport along the pipe wall to the lubrication point. Compressed air is used to flow in the pipeline, which drives the lubricating oil to flow continuously along the inner wall of the pipeline and conveys the oil-gas mixture to the lubricating point. Compressed air is supplied continuously at a constant pressure of about 0.3-0.4 MPa, while lubricants are supplied quantitatively according to the amount of friction consumed. Therefore, it is necessary to use the oil pump as the power source of oil transmission, and the progressive oil feeder is used to supply the required amount of oil for each lubrication point. The principle of oil and gas mixing is shown in figure 1..
3. system composition
The system consists of electronic control device, oil supply device, oil filter device, oil distribution device, gas source treatment device, oil-gas mixing device, oil-gas transmission pipeline and oil-gas distribution device. The electronic control system consists of UniMAT PLC system, HMI system, low-voltage electrical apparatus, sensors and actuators. The configuration of UniMAT PLC system is shown in table 1..
Table 1:UniMAT PLC system configuration
|
No |
Name |
Series No. |
Unit |
Qty |
| 1 |
CPU224 |
UN 214-1AD23-0XB0 |
PCS | 1 |
| 2 |
EM223 8DI/8DO |
UN 223-1BH22-0XA0 |
PCS | 1 |
UniMAT CPU224 has the following advantages over similar products in the market: additional PPI communication ports are added to avoid the trouble of customers not using touch screen and programming cable communication ports at the same time, only plugging and pulling ports constantly; battery-free, power-down data can be maintained for up to 10 years; faster command execution speed A single Boolean operation instruction is three times that of a similar Siemens product; it is compatible with the Siemens S7200 instruction set; it can directly replace the Siemens 224 controller module. The appearance of UniMAT CPU224 products is shown in figure 2.
4. control process
The electrical control system of the oil and gas lubrication system is a PLC control system. The core is composed of upper computer and lower computer. The upper computer is UniMAT CPU224 PLC, and the lower computer is LCD touch screen or HMI. The user interface is friendly and easy to operate. The LCD touch screen can display all kinds of setting parameters and running state of the system. Users can change the local mode, remote mode and testing mode of the system. Users can also modify the system parameters according to actual needs, and display the fault location and report when the fault occurs. In addition, the password protection function also requires the user to change the system settings when identifying parameters to ensure that the system is not random operation. The control process diagram is shown in figure 3..
There are three kinds of medium in oil-gas lubrication system, namely oil, gas and oil-gas. A perfect oil-gas lubrication system should have the function of monitoring these three kinds of medium to ensure that all parts of the system are known about their operation status. Once the fault occurs, the fault signal can be sent out in time to avoid serious consequences.
The main contents of the monitoring system are as follows:
Monitoring of oil: level switch monitors tank level, alarms when liquid level is low, stops pump when liquid level is too low; pressure switch detects oil pressure, controls pump start and stop according to oil pressure; temperature controller detects oil temperature, controls heating rod start and stop according to oil temperature; proximity switch monitors progressive distributor itself and its upstream oil supply department. Whether the whole fuel supply process is normal or not.
Gas monitoring: Pressure switches monitor the pressure of compressed air, and can be used to determine whether the air filter element is blocked.
Oil and gas monitoring: there are two ways to monitor oil and gas, one is transparent hose, can intuitively observe the operation of oil and gas flow, economic and practical; the other is the flow switch, with LED display, can observe the change of oil and gas flow, oil and gas flow speed is too slow or stop, will send an alarm signal.
Report errors
5.system effectiveness
The protection effect and economic benefit of the system are obvious.
1). The lubrication effect is satisfactory, which greatly prolongs the service life of the bearing.
2), greatly reduce the rate of sticky roll and reduce the consumption of waste and roller due to sticky rollers.
3), to prevent external debris and water intrusion into bearings is conducive to the bearing seal;
4), the consumption of lubricants is sharply reduced, which is only equivalent to that of dry oil lubricated 1/4.
5), the maintenance and operation costs are greatly reduced.
6). The processing cost of waste dry oil is zero continuous casting oil air lubrication technology.
7). The pollution of equipment running environment and cooling water caused by the leakage of dry oil has been completely eliminated, and the cost of water treatment has been reduced.
6.concluding remarks
UniMAT PLC used in oil-gas lubrication control system shows high compatibility with Siemens PLC and excellent performance stability. UniMAT PLC can completely replace Siemens products, ensuring the stability of the product while reducing the manufacturer's production costs.
