Mechanical seal selection and installation requirements

Mechanical seals are precision, structure is more complex mechanical one of the basic components of a variety of pumps, reaction of the synthesis reactor, the key components of the turbine compressors, submersible motors and other equipment. Sealing performance and service life depends on many factors, such as selection, the accuracy of the machine, proper installation use.

First, the selection method

Mechanical seal according to different working conditions and medium properties, high temperature, low temperature mechanical seals, high pressure, corrosion-resistant mechanical seal, granular media mechanical seals and adapt easy to vaporization of light hydrocarbon medium mechanical seals, etc., should be based on different useful to select a different structure type and material mechanical seal.

The selection of the main parameters: the seal chamber pressure (MPa), the fluid temperature (℃), speed (m / s), the characteristics of the fluid and install a sealed space.

The selection of the basic principles of:

According to the seal chamber pressure to determine the sealing structure with balanced or unbalanced type, single face or double face.

According to the pace of work, determine the use of rotary or static, hydrodynamic pressure and non-contact type.

Installation sealed space to determine the multi-spring or single spring or wave springs, built-in or externally mounted.

According to the temperature and fluid properties, determine the friction pair and the secondary seal, and the correct choice of lubrication, washing, insulation, cooling and other mechanical seal cycle protection system.

5 Install

Installation method is different with different types of mechanical seal type, machine almost the same, but the installation essentials, installation procedures and precautions are as follows:

(1) installation to determine the size

Installation, should be the product manual or sample to ensure that the size of the installation of mechanical seals.

(2) into the shaft (sleeve), the gland should be no glitches, bearing in good condition; seals, shaft seal chamber, capping should be cleaned. To reduce friction, shaft mechanical seal parts to be coated with a thin layer of oil, lubrication, taking into account the compatibility of the rubber O-ring should not be oil, can be coated with soap and water. The float-mounted stationary ring of anti-resale without structure, and should not be oiled, should be dry-loaded gland.

(3) with the first stationary ring and gland mounted on the shaft, be careful not to collide with the axis, and then the moving ring assembly load. The spring seat or the driving seat set screws should be divided into several evenly tightened.

Not fixed gland before he pushed the compensation ring for axial compression and release the compensation ring bounce card hysteresis phenomenon, then the gland bolts evenly locking.

6. Use

(1) operation before hand drive cars, pay attention to torque is too large, with or without a collision and not the sound.

(2) When the transmission medium temperature high, too low, or impurities particles, flammable, explosive, toxic, must be taken to the corresponding resistance seal, washing, cooling, filtration and other measures.

(3) Note the rotation, the appropriateness of whether the coupling of the lubricant additive, the bearing parts, piping is correct.

(4) operation before the first medium, the cooling water valve to open, check the seal cavity, the gas full discharge to prevent the static pressure, causing a leak, and then switched.

(5) after driving for work is normal and stable, with or without shaft rotation caused by the abnormal torque, as well as abnormal noise and overheating.

Second, the mechanical seal installation and use requirements

1, mechanical seal requirements for the accuracy of the machine (pump mechanical seals, for example)

(1) mechanical seal parts of the shaft (or sleeve) radial runout tolerance of not more than 0.04 ~ 0.06mm.

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

(3) sealed cavity and sealed end caps combined with positioning the surface of the end face of shaft (or sleeve) beat the tolerance of not more than 0.04 ~ 0.06mm.

2, the seal to confirm

(1) to confirm the installation seal is consistent with the requirements model.

(2) prior to installation to be carefully compared with the assembly diagram, the number of parts are complete.

(3) and circle the spring drive mechanical seal, the spring left and right hand of the points, in accordance with the shaft rotation has always been to choose.