D-type Rotary Joint: Introduction To Structure And Characteristics

D-type rotary joint is a specially designed rotary joint, and the following is a detailed introduction to it:

1、 Definition and purpose

D-type rotary joints are a series of products specifically designed for hot water, and can also be used for various other media such as steam (including saturated steam, superheated steam), hot oil, air, etc. It can input fluid medium from a stationary pipeline into rotating or reciprocating equipment, and then discharge it from a rotating joint, achieving dynamic connection and transmission. This type of joint is widely used in various industries such as steel, paper, rubber and plastics, textile printing and dyeing, glass, medicine, and chemical engineering.

2、 Structure and Characteristics

The main structure of a D-type rotary joint includes a compensator, a D-ring (also known as a flat ring), a liner (fixed D-ring), a hollow shaft, bearings, and other components. Among them, the compensator is composed of a bellows and a spring, which can not only compensate for the sealing effect of pushing the D-ring, but also directly seal the direct contact between the circulating medium of the pipeline and the shell. The D-ring is fixed by a liner to ensure that it does not deviate.

The characteristics of D-type rotary joints include:

a. Good sealing performance: Adopting corrugated compensator and floating sealing ring as the main form of dynamic sealing, the seal can be freely adjusted and compensated, making the seal more reliable and stable. At the same time, the use of a double end face sealing structure further improves the sealing performance.

b. Wear resistance: The sealing ring is made of impregnated carbon graphite, which has good self-lubricating properties, can reduce friction and wear, and improve service life.

c. High rotational accuracy: The use of bearings not only provides support, but also improves rotational accuracy and reduces friction torque.

d. Corrosion and high temperature resistance: The stainless steel bellows compensator makes the rotary joint more corrosion-resistant, and the spring outer installation does not come into contact with the medium, making the seal more reliable. At the same time, the working temperature of D-type rotary joints can reach 220 ℃ (some products such as Changqing DS type can reach 250 ℃), suitable for high temperature environments.

3、 Working principle

The working principle of D-type rotary joint is that when the rotating component rotates, the sealing element inside the joint body rotates and maintains contact and sealing with the rotating component. At the same time, the fluid medium is transmitted to the corresponding position of the rotating component through the channel inside the joint body, achieving dynamic connection and transmission of the fluid. The combination of corrugated compensator and floating sealing ring can achieve free adjustment and compensation of sealing, ensuring the sealing effect.

4、 Selection and Application

When selecting a D-type rotary joint, the following factors need to be considered:

a. Media type: Select the appropriate sealing material and sealing structure based on the type of media used in the system.

b. Work pressure: Choose the appropriate connector model and specification based on the system's work pressure.

c. Rotation speed: Select the appropriate bearing type and lubrication method based on the rotation speed of the rotating components.

d. Installation space: Choose the appropriate joint size and shape based on the installation space of the equipment.

D-type rotary joints are widely used in various fields, such as conveying high-temperature and high-pressure media such as steam and water on steel production lines; Used in papermaking machinery to meet the rotational requirements of equipment and seals; Used in the processing of rubber and plastic to transport media such as hot oil and water for heating and softening materials; Used in textile printing and dyeing equipment for conveying dyes, auxiliaries, and other media.

5、 Maintenance and upkeep

In order to ensure the long-term stable operation of the D-type rotary joint, regular maintenance and upkeep are required. Specific measures include:

a. Regular inspection: Regularly check the sealing performance and operation of the joints, promptly identify and handle problems.

b. Cleaning and replacement: Regularly clean the impurities and dirt inside the joint, replace severely worn seals and bearings.

c. Lubrication and maintenance: Regularly add lubricant to the joints to maintain the lubrication status of the bearings and seals. When working at high temperatures, it is also important to regularly add lubricating oil.

In summary, D-type rotary joint is a high-performance and widely used rotary joint product. In the process of selection, use, and maintenance, it is necessary to fully consider factors such as medium type, working pressure, rotation speed, and installation space to ensure its long-term stable operation.