1. Selection method

Mechanical seal according to the working conditions and dielectric properties of textile printing and dyeing machinery seal is different, have a high temperature resistant, resistant to low temperature mechanical seal, mechanical seal, high pressure resistance and corrosion resistance of granules medium mechanical seal and adapt to vaporize the mechanical seal of light hydrocarbon medium, etc., should be according to the different use to select different structure and materials of mechanical seal.

The main parameters of selection include: sealing chamber pressure (MPa), fluid temperature (℃), working speed (m/s), fluid characteristics of the packaged mechanical seal and effective space for the installation of seals, etc..

The basic principles of model selection are:

1. According to the pressure of the sealing cavity, determine the sealing structure to be balanced or non-balanced, single end face or double end face, etc.

2. According to the working speed, determine the use of rotary or static, fluid dynamic pressure or non-contact type.

3. According to the temperature and fluid properties, determine the friction pair and auxiliary sealing materials, as well as the correct choice of lubrication, washing, heat preservation, cooling and other mechanical seal cycle protection system.

4. According to the effective space for installation and sealing, determine to use multiple springs or single spring or waveform spring, internal or external installation.

Ii. Installation and use requirements of mechanical seals

1. Requirements for machine precision of mechanical seal (take mechanical seal for pump as an example)

(1) the maximum radial runout tolerance of the shaft (or shaft sleeve) at the installation of mechanical seal shall not exceed 0.04 ~ 0.06mm.

(2) axial movement of the rotor shall not exceed 0.3mm.

(3) the maximum run-out tolerance of the positioning end facing the shaft (or shaft sleeve) surface combined with the sealing cavity and the sealing end cover shall not exceed 0.04 ~ 0.06mm.

2. Seal confirmation

(1) confirm that the seal installed is consistent with the required type.

(2) before installation, please carefully check with the final assembly drawing to see whether the number of parts is complete.

(3) the use of parallel coil spring drive mechanical seal, the spring can be left, right, according to the rotation axis of the choice.

3. The installation

The installation method varies with the type of mechanical seal and the type of machine, but the installation essentials are almost the same. The installation steps and precautions are as follows:

(1) determination of installation size

Installation, should be in accordance with the product instructions or samples, to ensure the mechanical seal installation size.

(2) before loading, the shaft (shaft sleeve) and gland shall be free of burr and the bearing shall be in good condition; Seals, shafts, sealing cavities and gland should be cleaned. To reduce friction resistance, the installation of mechanical seal shaft parts to thin layer of oil, in order to lubricate, considering the rubber O ring compatibility, if not suitable for oil, can be coated with soapy water. Floating static ring without anti - pin structure, should not be oiled, dry type loading gland.

(3) first install the static ring and the gland on the shaft, pay attention not to touch the shaft, and then install the moving ring assembly. The set screw of spring seat or drive seat should be tightened evenly several times.

Before the gland is fixed, push the compensation ring by hand for axial compression. After releasing the compensation ring, it can automatically spring back without stagnation, and then lock the gland screw evenly.

Use 4.

(1) when the transmission medium temperature is too high, too low, or contains impurities particles, flammable, explosive, toxic, must take the corresponding blocking, washing, cooling, filtering and other measures.

(2) turn the car by hand before operation, and pay attention to whether the torque is too large, whether there is any rubbing or abnormal sound.

(3) pay attention to the rotation, whether the coupling is aligned, whether the lubricating oil addition of the bearing part is appropriate, whether the piping is correct.

(4) before operation, firstly open the valve of medium and cooling water, check whether all the gas in the sealing chamber is discharged to prevent static pressure from causing leakage, and then start the operation.

(5) after starting, whether the work is normal and stable, there is no abnormal torque caused by shaft rotation, abnormal sound and overheating.