How do Compressor Tilting Pad Journal Bearings meet the high load requirements of compressors through multi-pad bearing? ​

1. Working principle of multi-pad bearing: scientific design of load dispersion​
The core design concept of tilting pad journal bearings is to carry the load together through multiple pads. During the operation of the compressor, the rotor will be subjected to multiple external forces such as its own gravity, gas force, and radial force caused by imbalance. Traditional single-pad or less-pad bearings are prone to local stress concentration problems when facing large loads due to their single load-bearing method. The multi-pad structure of the tilting pad journal bearing can evenly distribute these complex loads to each pad. ​
Each pad is like an independent support unit. When the journal is running, they will automatically adjust their position and angle according to the changes in the load they are subjected to. When the journal is offset by the radial force, the oil film pressure distribution between each pad and the journal will also change accordingly. The pad with high pressure will automatically adjust its angle to reduce the oil film pressure; the pad with low pressure will adjust its angle to increase the oil film pressure. Through this adaptive adjustment process, multiple pads work together to share the load, thus effectively avoiding premature wear or failure of a pad due to excessive load, and achieving stable bearing of large radial forces. ​
II. Design and manufacturing process: the key to accurate adaptation to working conditions ​
(I) Selection of the number of pads ​
When designing tilting pad radial bearings, the determination of the number of pads needs to comprehensively consider factors such as the actual working load size, speed and operating conditions of the compressor. For compressors with large working loads, high speeds and more complex working conditions, a larger number of pads are usually selected. Because more pads mean more refined load dispersion capabilities, which can better cope with complex and changing load conditions. For some compressors with relatively small loads and relatively stable operating conditions, the number of pads can be appropriately reduced to reduce manufacturing costs and simplify the structure. Through precise calculations and simulation analysis, engineers can determine the number of pads that best suit a specific compressor, ensuring that the bearings meet the load-bearing capacity requirements while achieving the best cost-effectiveness. ​
(II) Design of pad size ​
The design of pad size is also crucial. The length, width and thickness of the pad directly affect the bearing's load-bearing capacity and operating performance. If the pad is too long, the oil film pressure distribution at both ends of the pad may be uneven when the journal rotates, increasing the risk of edge wear; if the pad is too short, it may not provide sufficient load-bearing area, reducing the bearing's load-bearing capacity. The width and thickness of the pad also need to be optimized according to the actual load conditions. Wider and thicker pads can withstand greater loads, but at the same time they will increase the weight and cost of the bearing; narrower and thinner pads are light and low in cost, but their load-bearing capacity is relatively weak. During the design process, engineers will use advanced mechanical analysis software to simulate and calculate pads of different sizes, comprehensively consider multiple factors such as load-bearing capacity, operating stability, and cost, and determine the most suitable pad size. ​
(III) Selection of pad materials​
The performance of the pad material directly determines the bearing's load-bearing capacity, wear resistance and service life. As mentioned above, the pad matrix is ​​usually made of high-quality steel or alloy steel to ensure that it has sufficient strength and toughness to withstand large loads without deformation or fracture. A layer of babbitt alloy with good friction reduction performance will be cast on the working surface of the pad. Different types of babbitt alloys differ in hardness, strength, corrosion resistance, etc., and are suitable for different working conditions. Under high load, high speed and extremely high wear resistance requirements, tin-based babbitt alloy with better performance will be selected; while in situations where the load is relatively low and the cost is more sensitive, lead-based babbitt alloy can be considered. By reasonably selecting the pad material, the tilting pad radial bearing can play the best load-bearing performance under different working conditions. ​
3. Comparison with traditional bearing structure: outstanding load-bearing capacity advantage ​
Compared with the bearing structure of single pad or less pads, the tilting pad radial bearing shows significant advantages in load-bearing capacity. Since the single pad bearing has only one load-bearing surface, when facing a large radial force, all loads are concentrated in this area, which can easily lead to excessive local stress and accelerate the wear and damage of the bearing. Although the bearing structure with fewer pads disperses the load to a certain extent, the dispersion effect is limited. Under complex and changeable working conditions, it is still difficult to meet the demand for high load.​
The multi-pad design of the tilting pad radial bearing makes the load distribution more uniform and efficient. During the operation of large compressors, even if they are subjected to sudden large radial force impact, the multi-pad structure can quickly adjust to distribute the impact force to each pad, avoiding excessive damage to a single pad. This ability to disperse the load not only improves the bearing's load-bearing capacity, but also greatly extends the bearing's service life and reduces the maintenance frequency and cost of the equipment. From the perspective of long-term operation, the tilting pad radial bearing has obvious advantages in both load-bearing capacity and economy. ​
IV. Practical application in large compressors: the core force to ensure stable operation ​
In large compressor equipment, the importance of tilting pad radial bearings is fully reflected. Taking the reciprocating compressor in a large fertilizer production device as an example, during the operation of this type of compressor, due to the high working pressure, the piston will generate huge inertial force when it reciprocates in the cylinder. At the same time, the gas forces inside the compressor are also very complex. These forces act together on the rotor, which places extremely high demands on the bearing's load-bearing capacity. ​
The tilting pad radial bearing can reliably withstand these complex loads due to its multi-pad load-bearing characteristics. During the startup, operation and shutdown of the compressor, multiple pads always work together to ensure that the rotor maintains a stable operating state. Even when the working conditions change, such as sudden load fluctuations, the pads can quickly adjust their positions and angles to maintain the stability of the oil film and ensure the normal operation of the bearings. It is precisely because of the stable support of the tilting pad radial bearing that large compressors can operate continuously and efficiently, providing a continuous source of power support for fertilizer production and ensuring the smooth progress of the entire production process.