Detailed explanation of methods to prevent lubricant loss during roller chain preheating

Detailed explanation of methods to prevent lubricant loss during roller chain preheating

I. Introduction
As a key component in mechanical transmission, roller chains are widely used in many industrial fields and mechanical equipment. Its efficient and reliable operation is closely related to lubrication. During the preheating process of the roller chain, the loss of lubricant will not only affect the lubrication effect, leading to increased wear and reduced transmission efficiency, but may also cause failures and increase maintenance costs. Therefore, it is of great practical significance to explore how to prevent lubricant loss during the preheating process of the roller chain.

2. Causes of lubricant loss during roller chain preheating

(I) Temperature influence
As the preheating temperature increases, the viscosity of the lubricant decreases. The decrease in viscosity makes it easier for the lubricant to lose from the gaps between the various components of the chain. At the same time, the increase in temperature may cause the light components in the lubricant to volatilize, change the physical properties of the lubricant, and further aggravate its loss tendency.

(II) Lubrication method and system defects
Improper selection of grease: If the dropping point of the grease is lower than the temperature during the preheating process of the roller chain, the grease will soften or even melt, and cannot be kept in the lubrication area, thus losing. For example, this situation is prone to occur when using sodium-based grease with a low dropping point at a higher temperature.
Improper amount of grease: Whether it is grease or lubricating oil, insufficient grease is difficult to form a complete lubricating film. Excessive grease will increase stirring resistance, generate more heat, and cause the lubricating oil to become thinner and lose.
Poor sealing of the lubrication system: If the lubrication system lacks effective sealing measures and cannot prevent external impurities from entering, the lubricating oil may also be lost during the preheating process due to pressure changes or gravity.
(III) Problems with the structure and installation of the roller chain itself
Manufacturing accuracy and fit clearance: During the manufacturing process of the roller chain, if the accuracy of each component is not high enough, and the fit clearance is too large or too small, it will affect the retention of the lubricating oil. If the clearance is too large, the lubricating oil is easy to leak; if the clearance is too small, the lubricating oil may be squeezed out due to thermal expansion.
Improper installation: When installing the roller chain, if the correct steps and methods are not followed, such as the chain is too tight or too loose, it may cause uneven force on the roller chain during operation and preheating, causing uneven distribution and loss of lubricating oil.

3. Choose the right lubricant
(I) Lubricant viscosity
The right viscosity lubricant should be selected based on the operating temperature, load and speed of the roller chain. Under high temperature, heavy load or high speed conditions, high viscosity lubricants are required to ensure that the lubricant can form a sufficiently thick lubricating film on the surface of the roller chain to prevent loss and provide good lubrication. For example, in the roller chain transmission of some large industrial equipment, when the temperature is high and the load is large, lubricants with a viscosity grade of ISO VG 220 or higher can be selected.
(II) Types of lubricants
Mineral oil: Mineral oil is relatively cheap and has good lubrication properties and certain oxidation resistance. For some roller chains with milder working conditions, such as roller chains in conveying equipment running at room temperature and at low speeds, mineral oil is a more suitable choice.
Synthetic oil: Synthetic oil has excellent high temperature stability, low temperature fluidity and oxidation resistance, and can maintain good lubrication properties over a wider temperature range. Synthetic oil is an ideal choice for roller chains working under extreme temperature conditions, such as high-temperature furnace equipment in the metallurgical industry or roller chains in low-temperature environments such as cold storage. Common synthetic oils include polyalphaolefins (PAO), ester oils, etc.
Grease: Grease is a semi-solid lubricant composed of base oil, thickener and additives. It has good adhesion and sealing properties, and can form a protective film on the surface of the roller chain to prevent the loss of lubricating oil. Especially in some roller chain applications where frequent refueling is difficult or sealing requirements are high, grease plays an important role. For example, in the roller chain transmission of some large outdoor machinery, the use of lithium-based grease can effectively prevent impurities such as rainwater from entering and reduce the loss of lubricating oil.
(III) Lubricating oil additives
Anti-wear additives: Anti-wear additives containing elements such as sulfur and phosphorus can form a protective film on the surface of the roller chain, reduce direct contact between metals, thereby reducing wear and preventing the loss of lubricating oil due to the generation of wear particles.
Antioxidant additives: Antioxidant additives can delay the oxidation and deterioration of lubricating oil and maintain its good lubrication performance and viscosity stability. This is especially important for roller chains that run for a long time, as it can reduce the viscosity reduction and loss caused by lubricant oxidation.
Anti-rust and anti-corrosion additives: In a humid or corrosive environment, anti-rust and anti-corrosion additives can prevent rust and corrosion on the surface of the roller chain, and also help protect the quality of the lubricant and prevent it from being contaminated and lost.

4. Optimize the lubrication system
(I) Adopt a reasonable lubrication method
Dripping lubrication: The lubricant is evenly dripped on a specific part of the roller chain through an oil dripping device. This method can accurately control the supply of lubricant according to the actual needs of the roller chain to avoid waste and loss of lubricant. Dripping lubrication is suitable for roller chain transmissions that run continuously and at high speeds. For example, in some automated production lines, dripping lubrication can maintain the good lubrication state of the roller chain.
Oil bath lubrication: The roller chain is partially immersed in the oil pool, and the lubricant is brought to each lubrication part through the movement of the chain. Oil bath lubrication is simple and convenient, and is suitable for roller chains with low speeds and small loads. In order to prevent the loss of lubricant in oil bath lubrication, the structure and oil level of the oil pool can be reasonably designed.
Pressure circulation lubrication: Use an oil pump to deliver lubricating oil to each lubrication point of the roller chain at a certain pressure. After lubrication, the lubricating oil flows back to the oil tank for cooling and filtration to form a circulating lubrication system. This method can ensure sufficient lubricating oil supply and take away heat and impurities in time. It is suitable for high-speed, heavy-loaded and large roller chain transmissions. In the pressure circulation lubrication system, by installing appropriate sealing devices and return oil pipelines, the loss of lubricating oil can be effectively prevented.
(II) Ensure the sealing of the lubrication system
Choose suitable sealing materials: The sealing material should have good oil resistance, temperature resistance and elasticity. Common sealing materials include rubber, polytetrafluoroethylene, etc. For example, in some high-temperature environments, fluororubber can be selected as a sealing material to ensure the sealing effect.
Reasonable design of sealing structure: The use of multiple sealing structures can improve the reliability of sealing. For example, at the shaft hole of the roller chain, a combination of lip seal and labyrinth seal can be used. The lip seal can fit the shaft surface tightly to prevent the leakage of lubricating oil, while the labyrinth seal uses its special structure to increase the resistance to lubricating oil leakage and further improve the sealing effect.
Regularly check and maintain the sealing device: During the use of the roller chain, the sealing device should be checked regularly for integrity, and damaged seals should be found and replaced in time to ensure the sealing of the lubrication system. At the same time, care should be taken to avoid damage to the sealing device during installation and maintenance.
(III) Install the oil level controller and alarm device
The oil level controller can monitor the oil level in the lubrication system in real time. When the oil level is lower than the set minimum oil level, it can issue an alarm signal in time to remind the operator to refuel. The alarm device can issue an alarm when the lubricating oil pressure is insufficient or the lubrication system fails, ensuring that the roller chain always has enough lubricating oil for lubrication during the preheating process to prevent the loss of lubricating oil.

5. Improve the structure and installation of the roller chain
(I) Optimize the structural design of the roller chain
Use sealed roller chain: The sealed roller chain adds a sealing device on the basis of the traditional roller chain, which can effectively prevent the loss of lubricating oil and the entry of external impurities. For example, some new sealed roller chains have rubber sealing rings or labyrinth sealing structures between the inner chain plate and the outer chain plate, which greatly improves the sealing performance of the roller chain.
Improve the shape of the sleeve and roller: By optimizing the geometry of the sleeve and roller, the storage space and retention capacity of the lubricant can be increased. For example, the sleeve is designed to be concave, so that the lubricant is more likely to gather inside the sleeve and reduce its loss during the preheating process.
(ii) Improve the manufacturing accuracy of the roller chain
Strictly control the manufacturing dimensions and tolerances of each component of the roller chain, reduce the matching clearance, and ensure the concentricity and straightness of the roller chain after assembly. This can ensure the uniform distribution of the lubricant inside the roller chain and reduce the loss of lubricant caused by excessive local pressure. At the same time, high-precision roller chains are also more stable during operation, which is conducive to extending the service life of the lubricant.
(iii) Correctly install the roller chain
Ensure the appropriate tension of the chain: When installing the roller chain, the tension of the chain should be correctly adjusted according to the requirements of the equipment and the instruction manual of the roller chain. If the tension is too large, the roller chain and bearing will be subjected to excessive force, causing the lubricant to be squeezed out; if the tension is too small, the chain will be loose and unstable, which will also affect the distribution and loss of the lubricant.
Pay attention to the installation direction of the chain: Some roller chains are designed with special requirements for lubrication and sealing in mind and have specific installation directions. When installing, they must be installed in the specified direction, otherwise it will affect the flow path of the lubricant and cause the lubricant to be lost.

6. Temperature control and monitoring

(I) Selection of preheating method
Use a slow and uniform preheating method to avoid sudden temperature rise and drop. For example, for the roller chain transmission system of large equipment, electric heating or steam heating can be used for preheating. By controlling the heating rate, the temperature of the roller chain and its lubricant is gradually increased to reduce the loss of lubricant due to rapid temperature changes.
(II) Cooling measures
During the preheating process of the roller chain, appropriate cooling devices, such as installing cooling fans or cooling oil circulation devices, can effectively control the temperature rise and prevent excessive dilution and loss of lubricant due to high temperature. The cooling fan can remove the heat from the surface of the roller chain by speeding up the air flow; the cooling oil circulation device can cool the lubricating oil and recycle it to maintain the viscosity and lubricating performance of the lubricating oil.
(III) Temperature monitoring
Install a temperature sensor to monitor the temperature changes of the roller chain during the preheating process in real time. According to the temperature monitoring data, adjust the preheating parameters and lubrication strategy in time to ensure that the operating temperature of the roller chain is within the appropriate range of the lubricating oil. When the temperature reaches the set threshold, the alarm is automatically triggered or the preheating operation is stopped to prevent the loss of lubricating oil and other faults caused by excessive temperature.

7. Regular maintenance and inspection
(I) Cleaning the roller chain and its lubrication system
Clean the roller chain and lubrication system regularly to remove oil, dust and impurities on the surface. Keeping the roller chain clean can prevent impurities from mixing into the lubricating oil, affecting the performance and lubricating effect of the lubricating oil, thereby reducing the loss of lubricating oil. When cleaning, use appropriate cleaning agents and tools, and be careful not to damage the roller chain and sealing device.
(ii) Check the quality and oil level of lubricating oil
Take samples regularly to check the appearance, viscosity, acid value and other indicators of lubricating oil to determine whether the lubricating oil has deteriorated or failed. At the same time, check whether the oil level is within the normal range and replenish or replace the lubricating oil in time. If the quality of the lubricating oil does not meet the requirements, it should be replaced in time to ensure the normal lubrication of the roller chain.
(iii) Check the wear of the roller chain
Regularly check the degree of wear of the roller chain, including the wear of rollers, sleeves, pins and other parts. According to the wear condition, adjust the tension of the roller chain or replace the severely worn parts in time. Severely worn roller chains will cause uneven distribution and loss of lubricating oil. Timely treatment can extend the service life of roller chains and lubricating oil.

8. Success Case Analysis
(i) Roller chain transmission system of an automobile manufacturing company
The company uses a large number of roller chain transmission systems on its automobile production line. During the preheating process, there was a serious problem of lubricating oil loss, which led to accelerated wear of the roller chain and frequent equipment failures. The following measures were taken to effectively solve the problem:
Select high-quality synthetic lubricants to improve the high-temperature stability and viscosity index of lubricants.
Optimize the lubrication system, adopt a combination of drip lubrication and pressure circulation lubrication, strengthen sealing measures, and install new sealing devices.
Improve the structural design of the roller chain, adopt a sealed roller chain, and improve manufacturing accuracy.
Install temperature sensors and oil level controllers to monitor temperature and oil level changes in real time to ensure lubrication conditions during preheating.
After these improvement measures, the company’s roller chain transmission system has greatly reduced the amount of lubricating oil lost during preheating, the service life of the roller chain has been extended by about 30%, the equipment failure rate has been reduced by 40%, and production efficiency has been significantly improved.
(II) Application of roller chains in a mining machinery
In mining machinery, roller chains are often used in conveying equipment and transmission devices. Due to the harsh mining environment, roller chains face the problem of easy contamination and loss of lubricating oil during preheating. The following are the measures taken by the mining machinery enterprise and the results achieved:
Select lubricating oil with extreme pressure anti-wear additives and anti-rust and anti-corrosion additives to adapt to the high humidity and high dust characteristics of the mining environment.
Add filtering devices in the lubrication system to regularly clean impurities to prevent impurities from entering the lubrication parts and causing lubricating oil loss.
Perform regular maintenance on the roller chain, including cleaning, inspection and replacement of worn parts to ensure the good operation of the roller chain.
Adopt reasonable preheating methods, control the preheating temperature, and strengthen the insulation measures of the equipment to reduce the impact of temperature changes on the lubricating oil.
Through the above measures, the loss of lubricating oil in the preheating process of the roller chain of the mining machinery has been effectively controlled, and the reliability and service life of the equipment have been significantly improved.

9. Conclusion
The loss of lubricating oil during the preheating process of the roller chain is a complex problem, but through comprehensive measures such as selecting suitable lubricating oil, optimizing the lubrication system, improving the structure and installation of the roller chain, controlling the temperature, and regular maintenance, the loss of lubricating oil can be effectively prevented to ensure the good lubrication state of the roller chain during the preheating process. This is of great significance for increasing the service life of roller chains, reducing equipment maintenance costs, and improving production efficiency. In practical applications, various methods and measures should be flexibly used according to the specific working conditions and requirements of roller chains, and continuous exploration and innovation should be carried out to achieve the best effect of roller chain lubrication.