1. The structural features of the imported shaft used for sealing products are introduced:
It consists of a PTFE wear ring and a rubber O-ring as a preloading element. It is a reciprocating seal that can withstand high pressure, low pressure, heavy load and alternating pressure.
Workpiece condition:
Motion form: unidirectional shaft seal
Speed: Max15mm/s
Pressure range: 0-60MPA
Temperature range: -30-200 C (depending on material of O ring).
Medium: Oil-based hydraulic oil, non-flammable hydraulic oil, environmental protection and safety hydraulic oil (bio-oil), water and other.
Commonly used materials: polytetrafluoroethylene PTFE, NBR butadiene rubber, FKM fluorine rubber.
Two. Introduction of Ding Qing wear-resistant imported O ring
1. NBR advantages: wear resistance, oil resistance, water resistance, heat resistance, high pressure oil resistance, with better mechanical properties and air tightness
2. NBR disadvantage: no polarity solvent, no heat resistance.
3. temperature: the limit is -40~120 C, the common temperature is -20~100 C.
4. hardness: A50-90 degree, commonly used hardness is 70 degrees, the acceptable pressure is 100kg =10 MPa MPA
5. Applicable media: hydraulic oil, gas, water, mud, crude oil, emulsion, water-glycol, acid.
Three. Properties of fluorine adhesive
1st. composition: vinyl fluoride + six fluorine propylene
Advantages: high temperature resistance, oil resistance, drug resistance, ozone resistance, weather resistance, aging resistance, chemical solvent resistance, smoldering, excellent air tightness, chemical resistance. Suitable for weak acid and weak alkali.
3rd. disadvantages: not resistant to ketones, lipids and nitrates.
4th. temperature range: -40~240 C at -20~220 C
5th. hardness range: hardness A50-90 degree 75 degrees commonly used
6th. color: Brown, black, secondary green.
Scope of application: engine stem seal, cylinder liner seal, clutch seal, fuel pump seal and fuel rubber tube inner glue, etc.
Four, PTFE material physical properties:
Polytetrafluoroethylene is the abbreviation of polytetrafluoroethylene, which is a polymer of tetrafluoroethylene. At present, it is a kind of polymer material with excellent corrosion resistance in the world. Its molecular formula is (C2F4) n, its relative molecular weight is 100, its melting point is 327 degree C, its boiling point is higher, its relative melting point can reach 400 degree C, its refractive index is 1.35, and the polytetrafluoroethylene itself has disappeared. Toxicity, PTFE has good elongation and compressive strength, high lubrication and non-stickiness, good voltage resistance, electrical insulation and good aging resistance. It can work steadily in a variety of working conditions.
1. High temperature: the working temperature is up to 250 C.
(2) Low temperature resistance: good mechanical toughness; even if the temperature drops to - 196 C, the elongation can be maintained at 5%.
(3) Corrosion resistance: For most chemicals and solvents, it shows inertia, strong acid and alkali resistance, water and various organic solvents.
Weathering climate: excellent aging life in plastics.
High lubrication: solid material with low friction coefficient.
Non adhesion: it is the surface tension of small and medium solid materials, and does not adhere to any substance.
No toxicity: it has physiological inertia and has no adverse reaction as implanted body.
Electric insulation: it can resist 1500 volt high voltage electricity.
Aging resistance: excellent wear resistance can effectively slow down the aging cycle.
High pressure resistance: it has high pressure resistance and can effectively maintain the stability of its own structure.
Polytetrafluoroethylene (PTFE) has been widely used as sealing and filling materials because of its high quality physical properties. All kinds of PTFE rings, PTFE gaskets, PTFE panels are widely used in all kinds of seals. The rapid rise and rapid development of PTFE materials means that the era of PTFE plastics is coming. PTFE materials, as a new direction, will guide and improve the development of industry and seals to a great extent.