Lubrication of mechanical equipment is an important task, and the rational application of lubrication technology to ensure the healthy operation of large mechanical equipment is the foundation for the rapid development of the national economy.

Wear and tear is one of the three main forms of damage to mechanical parts (wear, corrosion, and fracture), and is a major reason for reducing machine efficiency, accuracy, and even scrapping. According to statistics, about 80% of damaged parts are caused by wear and tear. About one-third of the world's current energy is ultimately consumed or overcome in some form of friction, with the equivalent of 3 billion tons of petroleum energy wasted each year. A survey in Canada shows that the losses caused by friction and wear can reach CAD 5 billion per year, and one-third of the losses can be recovered through the promotion of lubrication results. A survey report in the UK indicates that the annual economic benefits obtained from lubrication are no less than 500 million pounds. Japanese statistics found in a survey of 700 equipment failures that 253 cases, accounting for over 36%, were caused by poor lubrication. According to statistics in our country, 55% to 60% of failures occur due to lubrication. The use of reasonable lubrication technology plays an immeasurable role in reducing wear, ensuring the normal operation of mechanical equipment, extending equipment life, reducing energy consumption, protecting the environment, ensuring safety, and ensuring product quality. Compared with other mechanical equipment, China's lubrication equipment has not made much progress in terms of automation and improvement of mechanical structure. Most mechanical lubrication still uses traditional lubrication equipment, and manual lubrication is widely used. Some factories even blindly develop production, neglecting the application, lubrication, and maintenance of machinery, resulting in malfunctions and causing the entire production system to shut down, with incalculable losses.

At present, the grease lubrication system of large mechanical equipment in China mostly adopts dual line centralized lubrication system and progressive centralized lubrication system, and manual lubrication is still widely used. These lubrication techniques cannot adapt to the upgrading of modern large-scale mechanical equipment, often resulting in insufficient and excessive lubrication. In recent years, some automatic lubrication systems have also been developed in China, mostly adding electrical control devices on the basis of traditional lubrication systems. The mechanical structure of the lubrication system has not changed much, so the shortcomings of traditional lubrication systems are inevitable. Large mechanical equipment is the basic equipment of the national economy and the main equipment force for enterprise production, which is related to the production efficiency and even the survival of enterprises. They are affected by many factors such as the large number of lubrication points, high temperature of equipment, and high dust, often resulting in situations where the lubrication points are oil-free or lack oil. For critical lubrication points, a lack of oil can cause severe equipment wear, and even shutdown or even cessation of production. Therefore, it is necessary to promote a reliable, efficient, and flexible lubrication technology on large mechanical equipment.

2、 The current situation and analysis of lubrication for large mechanical equipment in China

        There are two main types of centralized grease lubrication systems widely used in large mechanical equipment: dual line centralized grease lubrication systems and progressive centralized grease lubrication systems.

        1） Dual line lubrication system

The dual line lubrication system is a primary method of centralized grease lubrication, mainly used for friction pairs in large mechanical equipment in industries such as metallurgy, machinery, mining, and chemical engineering. The dual line centralized grease lubrication system mainly consists of an electric lubrication pump, a directional valve, a dual line distributor, a differential pressure switch, and accessories for the electrical control box pipeline. The dual line distributor is the iconic component of the system, and its working principle determines the composition of the system.

The process of the dual line centralized lubrication system is as follows: the lubrication pump sends lubricating grease to pipeline 1, and the distributor on pipeline 1 is driven by the supplied lubricating grease. When the pressure in the oil pipe reaches the required pressure for the distributor to operate, the distributor can start operating. The completion of the distributor's action causes the pressure inside the oil supply pipe to rise. After the lubrication points on pipeline 1 have completed the oil delivery, the pressure difference switch at the end of the main pipeline will activate and transmit a signal to the electrical control box. According to the pre-set program, the electrical control box will reverse the direction of the directional valve and send lubricating grease to pipeline 2. The oil delivery process in pipeline 2 is the same as that in pipeline 1. After pipeline 2 completes the oil delivery, the pressure difference switch will receive the pressure signal and control the directional valve to reverse direction. At this time, in manual operation mode, the lubrication pump stops and waits for the next cycle; In continuous working mode, it automatically enters the next cycle. The schematic diagram of the dual line centralized lubrication system is shown below:

The dual line lubrication system has the following characteristics:

1. High oil delivery pressure and large flow rate

The distance of oil transportation is long, and there are many lubrication points;

The oil supply amount of each point can be easily adjusted by adjusting the limit nut of the distributor's oil supply piston;

One distributor is broken, but it does not affect the operation of the entire system, so it is difficult to determine whether the lubrication point has been lubricated properly

The layout of pipelines must use double lines, with multiple joints and a large amount of maintenance

6. High failure rate of differential pressure switch

        2） Progressive lubrication system

The progressive centralized lubrication system sends grease through the main lubrication pump to the single line pipeline, main progressive distributor, branch pipeline, sub progressive distributors at all levels, oil supply pipe, and finally to each oil supply point. This includes electronic control devices, limit switches, etc. The oil supply action of the progressive lubrication system is carried out sequentially one by one. This is because when the previous plunger pushes the oil discharge into place, it happens to activate the oil circuit of the next plunger. Therefore, once a certain oil supply point is blocked, its subsequent actions cannot be carried out, and all distributors will stop working. By utilizing this feature, a travel switch can be installed on a distributor to control and monitor the operation of the entire system and perform fault diagnosis. Its characteristics are as follows:

1. Single line oil supply, the oil supply action is carried out sequentially one by one

Any malfunction in one location will cause the lubrication system to malfunction

3. The system can be expanded through pump components.

However, the centralized lubrication systems developed domestically have added some electrical control equipment on the basis of the original centralized lubrication equipment, and the mechanical parts of the original lubrication equipment have remained basically unchanged. In this way, some of the shortcomings of the original centralized lubrication system cannot be cured. For example: 1. Traditional lubrication systems are bulky and have low reliability; 2: The amount of grease in traditional lubrication systems is often distributed based on human perception and experience, rather than on demand, often resulting in excessive or insufficient lubrication; 3: Traditional lubrication system oil level indication, alarm, protection and condition monitoring devices are mostly independent and decentralized, requiring manual inspection; 4: Traditional lubrication systems are limited by the number and distance of lubrication points. The number of points cannot be too many, and the distance cannot be too far, otherwise the lubrication effect will be very unsatisfactory; Traditional lubrication systems have slow updates and cannot adapt to the rapidly changing development of mechanical equipment.

Due to the above reasons, the equipment operates in a state without lubricating grease or poor lubrication, which exacerbates equipment wear and leads to oil shortage and even jamming, greatly shortening the maintenance cycle, increasing maintenance workload, and significantly increasing maintenance costs. However, due to inherent defects in the lubrication system that cannot be overcome, the problem has not been fundamentally resolved. This time we introduce the new product developed by Beijing MCC Huarun Technology Development Co., Ltd,ZDRH one 3The 000 intelligent centralized lubrication system is developed to address the aforementioned contradictions, combining microcomputer technology with programmable control to bring equipment lubrication into a new field of intelligence.

3、 The functions of the new intelligent lubrication equipment

1. Composition and functions of the system

The ZDRH-3000 intelligent centralized lubrication system is divided into main control equipment, oil station, on-site controller, oil circuit, control and signal lines

Road and other parts.

A main control device

The main control equipment is the command device of the lubrication system, and its main functions include:

(1) Control the start stop of the gas station, regulate the distribution of oil volume and duration by the on-site controller;

(2) On site information collection;

(3) Reflect the on-site situation of lubrication points;

(4) Control loop timing;

(5) Control and adjust the oil supply quantity and time of each lubrication point.

B oil  stand

The oil station is the core of the entire lubrication system, and its main function is to deliver lubricating oil to each lubrication point through pipelines and on-site controllers.

C on-site controller

The on-site controller is the executing device of the lubrication system, and its main functions include:

(1) Execute instructions from the main control device;

(2) Open or close the oil supply control valve of the lubrication point to control the oil supply quantity and time.

D oil  road

The oil circuit is divided into main oil circuit and branch oil circuit, and its main functions are:

(1) The high-pressure lubrication pump delivers lubricating oil through the main oil circuit to the on-site controller;

(2) The on-site controller delivers lubricating oil to various lubrication points through branch oil circuits according to the set program.

E Control and signal lines

The control and signal lines are divided into two parts: manual control system and automatic control system.

(1) Manual control system. When the system is manually controlled to operate, there is a manual interface on the touch screen of the main control panel. The following manual operations can be performed on the manual interface: manually click the oil pump start switch, the oil pump starts to inject oil into the main oil circuit, manually enter the lubrication point number, and then click the start switch of the manual oil injection switch. The on-site controller receives the signal, opens the solenoid valve, and injects lubricating oil into the lubrication point to achieve equipment lubrication. The amount of oil supply can be adjusted completely according to the actual demand of the lubrication point.

(2) Automatic control system. When the lubrication system operates under automatic control, the programmable logic controller (PLC) runs automatically according to the pre programmed program, and the oil pump automatically opens. At the same time, the on-site controller will be connected, and then the lubrication points numbered 1, 2, 3,... 79, 80 will be opened, supplied, and closed in sequence. If there are a total of 80 lubrication points in this lubrication system, after the last lubrication point completes oil supply, the last on-site controller will shut down and the oil pump will automatically stop. When the next cycle starts, the time controller will start timing again. At each lubrication point, the main control equipment displays that the point is supplying oil, and the pressure relay monitors the on-site oil supply and oil pump operation at any time. After the set lubrication system oil supply time expires, the oil pump starts automatically again, and at the same time, each lubrication point opens, and the next oil supply cycle begins. The oil supply time of each lubrication point and functional lubrication system can be changed by modifying the PLC program.

Technical advantages of the ZDRH-3000 intelligent centralized lubrication system

The technical advantages of the ZDRH-3000 intelligent centralized lubrication system are as follows:

(1) Using PLC to achieve remote control of lubrication points;

(2) Implement real-time monitoring of network connectivity and microcomputer communication;

(3) Microcomputer controlled timed and quantitative fuel supply, and the ability to adjust fuel supply parameters at any time; Large mechanical equipment has different bearing oil supply and cycle times according to different working environments. The cycle time and oil supply size of each bearing can be adjusted by the operator according to the needs of the on-site equipment, with oil supply time as the main and cycle time as the auxiliary. This can ensure equipment lubrication without causing waste of lubricating oil;

(4) By using pressure sensors, real-time monitoring is achieved to ensure that the internal pressure value of the pipeline remains within a large range when oil is discharged from each lubrication point, ensuring that the power of oil discharge is sufficient and that the pressure value will not be too low due to distance, preventing normal oil discharge;

(5) Advanced high-pressure and high flow oil pump, stable and reliable;

(6) Advanced flow sensors monitor the real operating status of lubrication points in real time. The status of each lubrication point is accurately fed back to the upper computer for normal and blocked preparation, and can reflect the precise location of the blocked point for system maintenance;

(7) Centralized management of dispersed lubrication points;

(8) Wireless control has been achieved between network connection, real-time monitoring, and main control, avoiding disadvantages such as high temperature, water cooling, and long distance that are not suitable for wiring, reducing failure rates, and lowering energy consumption.

4、 Conclusion

The ZDRH-3000 intelligent centralized lubrication system can adjust the oil supply to each lubrication point according to the needs of the on-site equipment, with the oil supply frequency as the main and the cycle time as the auxiliary, ensuring equipment lubrication without causing oil waste. Intelligent, automatic, and real-time monitoring are its outstanding advantages. This system has been used by multiple domestic enterprises until now, and it runs stably and reliably. It is easy to adjust the oil (grease) supply, locate fault points, maintain small amounts, avoid environmental pollution and grease waste, extend equipment maintenance cycles, and meet the intelligent needs of industrial control processes for large mechanical equipment. After the transformation of the intelligent automatic lubrication system, the downtime of equipment failures and the consumption of spare parts and materials have been greatly reduced, while the labor intensity of workers has been reduced, achieving significant economic and social benefits.