abstract
This article mainly introduces the development and application of the ZDRH series intelligent lubrication system developed by Beijing MCC Huarun Technology Development Co., Ltd., with a focus on the intelligent characteristics of the system. The system is mainly divided into a main control unit, an executing mechanism, a flow detection mechanism, and an upper computer. The main control unit adopts the reliable Siemens S7-200 (300) PLC, which fully adapts to complex industrial control environments. The execution mechanism includes an electric high-pressure lubrication pump, solenoid valve, etc. The detection mechanism is a flow sensor, which detects the flow of lubricating grease. The upper computer software is a self-developed lubrication system specific monitoring software or a general Siemens WINCC configuration software, which monitors the start and stop of the lubrication pump, the opening and closing of the solenoid valve, the flow feedback signal, and records the previous oil supply status of the lubrication point in real time. The system can be started and stopped, parameter edited, and manually operated on the upper computer.
key word:MCC China Resources, Intelligent Lubrication ZDRH、 Lubrication pump, Siemens PLC
1 Introduction
With the development of mechanical and electronic technology, industrial control technology continues to advance. Innovative electromechanical equipment liberates people from simple and repetitive labor, improves production efficiency, and reduces labor costs.
The earliest lubrication methods were manual lubrication and oil cup lubrication. These methods can still be used for small equipment with few lubrication points and long refueling cycles, but are not suitable for situations with many lubrication points and large oil demand.
Later, it developed into centralized lubrication, mainly including single progressive lubrication, double line and multi line lubrication systems. This type of lubrication system has dominated the market for many years and is still widely used today. All three types of lubrication systems have the following theoretical problems that cannot be solved.
Single line progressive lubrication system
Principle: There is only one main pipeline, and usually a plunger pump injects lubricating grease into the main pipeline. The lubricating grease is then sent to the next level distributor through a single line progressive distributor, and finally to each lubrication point. As long as one lubrication point does not produce oil, all progressive distributors do not produce oil, and the system pressure will increase. When the alarm upper limit is reached, the system will report a fault and stop running. The first level principle system has the following drawbacks:
▷The maintenance efficiency, that is, the system principle directly affects the safety of the system. Once a single lubrication point does not produce oil, all points in the system will no longer produce oil. If you want to find the fault, you need to inspect each lubrication point one by one until you know the specific lubrication point location, which is quite time-consuming to repair.
▷The fuel supply radius is small, and due to the distribution of single lines in a hierarchical manner, the requirements for the supporting pipelines cannot exceed 2 meters. If they are too long, it will directly affect the quality of lubrication. The system is only suitable for places where several lubrication points are located in close proximity.
Dual line lubrication system
Principle: The dual line centralized lubrication system mainly consists of a lubrication pump, a directional valve, a differential pressure switch, a bidirectional distributor, an electric control box, and two oil supply pipelines. The lubricating grease output by the lubrication pump is alternately transported to the dual line distributor through the directional valve through the two oil supply pipelines, and quantitatively distributed to each lubrication point through the dual line distributor. The pressure inside the oil supply pipeline reaches the required operating pressure of the distributor, and the distributor operates. After the distributor completes its operation, the pressure inside the oil pipe continues to rise. When the pressure in the oil supply pipeline has caused the distributor to complete its operation (the system completes one oil supply run), the system pressure rises to the reversing pressure of the reversing valve, and the reversing valve switches to perform a second oil supply. According to the principle, the system has the following drawbacks:
▷ The system is supplied with oil alternately through two pipelines, and the oil circuit is opened by reversing the direction based on the pressure difference. As a semi fluid lubrication pipeline, the pressure drop must be considered. If the pressure drop at the initial and final ends is too large, it can easily cause uneven oil output at the proximal and distal ends.
Whether the lubrication points have oil leakage is indicated by the oil needle. Each point needs to be inspected on site one by one after each operation. If the user is not careful, they may miss the inspection.
The oil supply can only be adjusted by adjusting the length of the oil needle, and it is difficult to meet the lubrication points of different oil supply systems.
Multi line lubrication system
Principle: With multi-point pump as the core, different lubrication points can be connected after each outlet, and the oil volume of each outlet can be adjusted. When the lubrication pump is working, each point will discharge oil according to the adjusted oil volume.
When the multi-point pump fails, all lubrication pumps will no longer supply oil
If a single lubrication point is blocked, it may cause damage to multiple lubrication pumps
Can't meet the oil supply needs of multiple lubrication systems
Based on the above centralized systems, the world's heavy industry and heavy equipment are looking forward to the emergence of a new type of dry oil lubrication system. Summarizing the advantages and disadvantages of various lubrication systems, combined with advanced automatic control technology and sensor technology in the world, a new generation of intelligent dry oil centralized lubrication system has been developed.
2. Working principle of intelligent lubrication system
The working principle of the advanced intelligent lubrication system independently developed by Beijing MCC Huarun Technology Development Co., Ltd. is shown in the following figure.
Lubricating grease is pumped into the main pipeline through an electric high-pressure lubrication pump and integrated into an electromagnetic oil feeder on site. The electromagnetic oil feeder integrates oil supply to lubrication points on site by controlling the opening and closing of solenoid valves. All lubrication pumps, grease storage tanks, and oil feeder integrations are controlled through a control cabinet. The upper computer monitoring system monitors the start and stop of the lubrication pump, main pipeline pressure, lubrication pump oil level, and other information in real time, and records the oil supply status of each lubrication point.
2.1 Functions of various parts of the system
2.1.1 Control Cabinet
The control cabinet is the brain of the entire system, controlling various actuators and receiving on-site flow feedback signals to determine the lubrication point oil supply status. It mainly consists of electrical components such as PLC, human-computer interaction equipment, AC contactor motor protector, intermediate relay, encoder, etc. The PLC adopts Siemens S7-200 (300) series PLC, and other electrical components are also imported brands with reliable performance to ensure stable and reliable operation of the system. Human computer interaction devices are usually touch screens, which display system information and can also be used for operations, parameter settings, etc.
2.1.2 Lubrication pump
The lubrication pump is the heart of the lubrication system, responsible for pumping lubricating grease into the main pipeline to ensure that the main pipeline maintains a certain pressure range during the oil supply process. There are usually two lubrication pumps, one in use and one as backup. Generally, plunger pumps are used to ensure that the main pipeline pressure is stable below 40MPa and the flow rate is 400ml/min. Pneumatic pumps can also be used to ensure that the main pipeline pressure is below 30Mpa and the flow rate is 700-800ml/min.
The lubrication pump is equipped with a weighing device or oil level detection device, which can convert gravity into analog electrical signals and send them to the PLC analog input module. The oil level detection device can send out dry contacts when the oil level is low or high.
2.1.3 Integration of electromagnetic oil feeder
The integration of electromagnetic oil feeder is the final actuator and detection component, consisting of components such as solenoid valve, flow sensor, information recognizer, etc. The information recognizer receives instructions sent remotely by the PLC to open or close the solenoid valve. At the same time, a flow sensor based on the Hall effect detects the oil level movement signal and sends it to the remote PLC.
2.1.4 Refueling System
Due to the limited oil storage capacity of the lubrication pump itself and the high cleanliness requirements of the plunger pump for lubricating grease, the refueling system is particularly important. Before entering the lubrication pump, a layer of filter screen is used to filter the lubricating grease, which can greatly improve the cleanliness of the grease and extend the service life of the plunger. There are two types of fuel pumps. The ordinary one is a gear pump, which can be directly inserted into a standard oil drum with an oil output of 200 or 400 L/h. Generally, only one is equipped to refuel the main pump. The other type is a large grease storage tank with a maximum capacity of over 5000 L, equipped with two fuel pumps and an internal mixer. The fuel pump is a worm pump with an oil output of 15 L/min. Large oil tankers are used to refuel the grease storage tank. Ultrasonic level gauges can be installed on the top to detect the oil level inside the tank.
2.1.4 Upper computer monitoring system
The upper computer is composed of an industrial control computer or a regular computer with monitoring software, which can monitor system operation information and perform operations, completing the operations that can be completed on the control cabinet HMI. The communication method is RS485 or Ethernet, and the communication distance is over 1000 meters.
3 Characteristics of Intelligent Lubrication System
The equipment adoptsThe SIEMENS S7-200 (300) series PLC, as the main controller, provides the most reliable solution for intelligent control of equipment lubrication. It can be connected to the upper computer through network connection for real-time monitoring, making the lubrication status clear at a glance; The on-site oil feeder is integrated and controlled by PLC, and the size of the oil supply and the length of the oil circulation time can be controlled at each point, and can be easily adjusted; The flow sensor detects the oil supply status of each lubrication point and records any faults for easy maintenance and repair by operators. Operators can adjust the oil supply parameters of lubrication points through the touch screen or upper computer according to the lubrication requirements of each point of the equipment, in order to adapt to different lubrication requirements of lubrication points. The system runs stably and reliably, with easy adjustment of oil (grease) supply, easy identification of fault points, minimal maintenance, greatly reducing manual labor intensity, avoiding environmental pollution and grease waste, extending equipment service life, reducing maintenance, and improving overall efficiency.
● 3.1 Control Points
● Control the maximum number of points to be1020 points
● Integrated control for each oil feeder4 points
The system points can be freely increased
● Bus type control, simple wiring
● 3.1 Point by point fuel supply
Feed oil in sequence according to the set program. The lubrication pump only supplies oil to one point per unit time, ensuring the pressure at each point during oil supply;
Oil supply can be provided to each point as needed1-99 times (3ml each time), set the oil volume arbitrarily;
The cycle time can be set arbitrarily according to needs;
Point by point fuel supply can be interlocked with system equipment.
3.2 Point by point detection
●Real time detection of displacement signals of oil in pipelines, accurately reflecting the oil supply status of lubrication points;
●Different from pressure and differential pressure signals. Due to the reliability of pressure and differential pressure signals, it truly reflects the oil supply status of lubrication points.
● 3.3 Intelligent fault diagnosis
● Can identify faults in each lubrication point and lubrication component;
Can identify the type of fault (blockage, passage, leakage, jamming, damage);
There is a database of fault types accumulated through years of practice in the program for practical reference.
● 3.4 Remote monitoring
Adapt to and meet the needs of modern factory automation production;
Truly reflect the oil supply status of each lubrication point, allowing equipment management personnel to have a clear understanding;
Remote setting and adjustment of fuel supply parameters for each point;
Can meet the urgent need for lubrication (importance) of current equipment.
● 3.5 Other
The ZDRH system can be used for fuel injection with simple modifications, atomizing thin oil and spraying it onto the meshing surface of gears or tugboats to form an oil film, reducing friction and wear.
4 System software design
Due to the use of PLC, the programming of the system is simpler and more flexible. The upper computer software can use general configuration software or specialized self-developed software, making system maintenance easier.
The software workflow is shown in the following figure:
5. On site operation effect
This intelligent lubrication system has been running on large equipment in domestic and foreign steel mills, such as sintering machines, grate machines
Blast furnaces, continuous casting machines, etc. operate well, greatly extending the service life of the main equipment, saving manpower, avoiding waste and pollution of lubricating grease, and creating benefits for customers.
6 Outlook
The intelligent lubrication system has been well promoted and used in large heavy equipment in the metallurgical industry, but the initial installation cost is high and the skill requirements for installation personnel are high, which makes it difficult to promote in some manufacturers. Therefore, there is an urgent need for a low-cost and easy to install and debug lubrication system.
The lubrication of other heavy equipment outside the metallurgical industry is still a relatively large market. For example, a set of engineering equipment suitable for small and medium-sized equipment such as excavators and shovels has been developed, which requires fewer lubrication points, limited installation space, and high vibration. Beijing MCC Huarun Technology Development Co., Ltd. has developed a small lubrication pump with a capacity of 6L-40L, which can fully meet the demand and has been running on some of these equipment with good results.
7 Conclusion
This article provides a brief introduction to the development of equipment lubrication, elaborates on the characteristics of lubrication equipment in different periods, and focuses on the ZDRH series intelligent centralized lubrication system independently developed by Beijing MCC Huarun Technology Development Co., Ltd., which has world advanced level.
ZDRHCan the application of intelligent centralized lubrication system enable customers to standardize the management of lubrication points, save manpower and material resources, extend the service life of equipment, and create objective benefits for customers.
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