In Taiwan and abroad, the rotary joint is also called "pressure rotary joint" or "rotary joint", and its function is to connect the dryer cylinder and the external pipeline. In the early days, people used sealed bags to wrap around the rotating shaft, and used friction and squeezing to prevent the leakage of the circulating medium in the dryer; of course, this method also has the advantage that the material is cheap and easy to find; but the disadvantages are also very great. Obviously, the service life is too short. It can only be used for more than ten days at a time. Not only does it increase the frequency of maintenance by maintenance personnel, but the ammonia decomposition always interrupts production and affects work efficiency.

Since the beginning of this century, swivel joints have been used abroad. The seals inside are made of metal, graphite, rubber and other materials. In order to pursue service life, most foreign countries have set up several sealing materials, and the circulating medium will not leak. As a result, the service life of the product is as long as more than ten years of membrane separation technology. However, due to the complexity of the manufacturing process, the structure is compact and complex, which is not easy to carry, and it also brings a lot of inconvenience to maintenance.
Domestic manufacturers mainly compete on price. In recent years, a large number of foreign advanced technologies have been introduced, which has gradually increased the variety of domestic companies' production, and more companies have begun to delve into self-developed fields.
Rotary joint has just been installed and used, the reasons for leakage and countermeasures:
1. The hollow shaft and the matching rotating body are not concentric enough. Disposal measures: check the size and accuracy of the steel pipe greenhouse, check the tightness of the metal hose, and adjust the fixed connection with the rotating body.
2. The clearance between the bottom hole of the shell or the bottom cover and the hollow shaft is not equal (the sealing ring is inclined). Disposal measures: adjust the hanging, supporting or guiding rod structure of the gas alarm to ensure the concentricity of the hollow shaft, the shell and the rotating body.
3. There is no evenly thickened gasket between the hollow shaft flange and the roller connecting boss and pit. Disposal measures: Leakage occurs at the connection part of the equipped equipment. Remove and add a washer of uniform thickness.
4. The accuracy of the assembly machine is low (the end face is perpendicular to the mechanical seal straightness, radial and axial clearance is large), and the vibration is large. Disposal measures: find out the cause, repair and match equipment.
5. The end face of the oil-free bearing, the friction pair contact surface is not tightly attached or broken (caused during assembly or handling). Disposal measures: Remove the rotary joint and replace the oil-free bearing or friction pair compensation ring.
6. The spring is smaller than the pressure. Disposal measures: reform the design and replace the spring.
7. The friction sealing surface is not running in. Disposal measures: After running-in and using for a period of time to reach equilibrium roughness, the leakage will stop.
8. The granular solid or foreign matter with higher hardness enters the cover room of the friction pair dense toxic gas detector during assembly or installation. Disposal measures: Grind the friction surface of the friction pair or replace the equipment.

Assembly and installation of one-way rotary joint and matching equipment:
When installing and assembling the one-way rotary joint with the equipment, usually apply white lead oil on the thread or wrap a few layers of soft film, fix it with a tool, and then align it with the threaded hole of the rotating body and rotate it in. Until it rotates.
When the hollow circumference and the rotating body equipped with the carbon monoxide detector can only be connected by flange, we should wrap the gasket on the end of the flange hollow shaft, and then match the end of the rotating body without distinction and screw holes, and fix it with bolts.
The correct way to use the rotary joint:
In our daily use, in order to use the rotary joint efficiently, we should maintain it at ordinary times. We should pay attention to some methods during maintenance. Here is a portable gas detector to summarize some correct use and maintenance methods:
1. It is best not to stop the machine for more than 72 hours. Lubricant should be dripped around the joint between the moving ring and the graphite ring before restarting. If the machine is not used for a long time, the parts will rust. Leakage will occur during maintenance.
2. The inlet must be connected by a hydraulic machine with a hose, and the length must be long enough.
3. Ensure that the bottom of the pipe is clean to prevent deposits from causing abnormal joints.
4. Avoid collision and damage during transportation.
5. The nitrogen generator should avoid idling when there is no medium circulating.
6. It should be in a suspended state when working.