Metallurgy and Steel Plant Rotary Union
Metallurgy Steel Plant Rotary Union
There are many types of rotary unions used in Metallurgy steel plants, mainly for cooling. Due to different mechanical equipment, the cooling rotary unions used are different and the requirements are different. Because of the installation space problem, built-in rotary joints are mostly used. However, for equipment with high speed requirements, we recommend that it is best not to use built-in products. If it can be installed externally, it is best to install it externally. The most widely used rotary union is still an external high-speed rotary union.
Built-in Rotary Union (commonly known as embedded type)
Installing most of the seals and shells inside the equipment can not only save space, but also reduce hot water leakage. A slight leakage inside the equipment only affects the cooling speed and will not affect the normal operation of the equipment. The speed of the built-in rotary union is also different due to the different internal structures. Because the pressure of the O-ring is too high, the product speed is low.
External Rotary Joint
Currently, most of the cooling rotary unions used in steel plants are cast copper parts, and a small number are stainless steel. Stainless steel is expensive, has high requirements for shell material, and is difficult to process. Steel mills mostly use copper castings. There are other metals inside the copper castings, which increase the pressure resistance and viscosity, but the texture is relatively soft and easy to fit with the seals. Another feature of the external rotary union is that the volume is much larger than the internal type, and it is easy to choose seals and sealing structures. This is also the reason why the price of the same rotary joint varies greatly. For example, the bearings and seals used can determine the price of the rotary union. The price of bearings may differ by up to 100 times, the difference between the quality of seals can also be as large as dozens of times, and even the price of sealing rings can differ by more than 10 times or 20 times. Therefore, when steel mills choose rotary unions, they will often indicate the required materials and sealing structures.
Steel mills also use many special rotary unions. For example, the rotary unions of continuous rolling mills have higher requirements and much larger size specifications. Some steel mills make steel plates and need to use large cooling rollers, so the selected rotary unions are also relatively large and have high speeds. For those steel plate manufacturers, the rotary joints must be durable and not expensive, so there are also many companies that use Q-type rotary unions instead of H-type rotary unions.
There is also a kind of steel mill that needs to use high-pressure two-way rotary unions. The characteristic of this rotary joint is high pressure, and the use pressure is about 50Mpa to 80Mpa, and the highest reaches 150Mpa. At present, many manufacturers only make rotary unions with a pressure of 5Mpa to 10Mpa, but they cannot meet the needs of some steel mills, especially some large steel mills. Although the amount is not much, the requirements are very high.