Mechanical seal works

Mechanical seal is by a pair or more relative to the axis perpendicular to the end face of the slide stretch (or magnetic) role in maintaining the seal affixed to merge with auxiliary devices to achieve the seal leakage barrier fluid pressure and compensation agencies.

2, the choice of mechanical seals commonly used materials

Shimizu; room temperature; (moving) 9Cr18,1Cr13 surfacing cobalt chromium tungsten, iron; (static) dip resin graphite, bronze, phenolics.

Water (including sediment); room temperature; (move) tungsten (static) WC

Seawater; room temperature; (move) tungsten carbide, 1Cr13 surfacing cobalt chromium tungsten, iron; (static) resin-impregnated graphite, tungsten carbide, cermet;

100 degrees is too hot; (move) tungsten carbide, 1Cr13 surfacing cobalt chromium tungsten, iron; (static) resin-impregnated graphite, tungsten carbide, cermet;

Gasoline, lubricants, liquid hydrocarbons; room temperature; (move) tungsten carbide, 1Cr13 surfacing cobalt chromium tungsten, iron; (static) dip or tin-antimony alloy graphite resin, phenolics.

Gasoline, lubricants, liquid hydrocarbons; 100 degrees; (move) tungsten carbide, 1Cr13 surfacing cobalt chromium tungsten; (static) Baptist graphite bronze or resin.

Gasoline, lubricants, liquid hydrocarbons; containing particles; (moving) WC; (static) tungsten carbide.

3, sealing material types and uses

Sealing material should meet the requirements of sealing function. Due to different medium to be sealed, and the different working conditions of the equipment, the requirements of the sealing materials having different flexibility. General requirements for sealing materials are:

1) material density, and not divulge media;

2) adequate mechanical strength and hardness;

3) compressibility and resilience, permanent deformation;

4) does not soften at high temperatures, does not decompose at low temperatures without hardening, embrittlement;

5) Good corrosion resistance, acid, alkali, oil medium, long-term work, small changes in volume and hardness, and does not adhere to the metal surface;

6) low coefficient of friction, good wear resistance;

7) having a sealing surface binding softness;

8) good resistance to aging, durable;

9) manufacturing convenient, cheap, easily drawn.

Rubber is the most common sealing material. In addition to the rubber, but suited to do as well as graphite sealing material, PTFE and various sealants.

4, mechanical seal installation, use technology essentials

1), radial shaft runout equipment should ≤0.04 mm axial runout allowed to be greater than 0.1 mm;

2), sealing parts equipment should be installed to keep clean, seal parts should be cleaned, seal face intact, to prevent impurities and dust into the sealing parts;

3), the installation process is strictly prohibited crashing, banging, so as not to damage the mechanical seal friction and seal failure to pay;

4), in contact with the sealing surface should be coated with a layer of clean oil when installing machinery in order to successfully install;

5) When installing static ring gland, tighten the screws must be by force, to ensure that the requirements of the stationary ring face and vertical axis line;

6) After installing hand to promote the snap ring, snap ring on the shaft allows the flexibility to move, and there is a certain flexibility;

7) After installing the hand plate moving shaft, the shaft should be no weight feeling;

8), the device must be filled with the media before the operation to prevent dry friction, seal failure;

9), for easy to crystallize, granular media, for medium temperature> 80oC, should take appropriate washing, filtration, cooling measures, various auxiliary devices, refer to the relevant standard mechanical seals.

10), in contact with the sealing surfaces should be coated with a layer of clean oil machinery installation, pay special attention to the selection of mechanical oil for different auxiliary materials to avoid O-ring expansion or invasion oil accelerated aging, causing the seal in advance failure.