WE HAVE THE GRAPHITE SOLUTION FOR YOUR APPLICATION

APPLICATIONS

  •  Vacuum Fornace insulation
  •  Inert Gas Fornace Insulation
  •  Inert Gas Atmosphere Equipment Insulation
  •  Reaction Vessel Linings
  •  Bearings
  •  Segmented Seals
  •  Piston and Guide Rings
  •  Mechanical Seals
  •  Steam Nozzles
  •  Water Turbine Gland Seals
  •  Packing Rings
  •  Contactless Seals
  •  Vanes
  •  Sealing Strips
  •  Stripping components
  •  Hollow and Container Glass Manufacture
  •  Flat Glass Production
  •  Heat Exchangers
  •  Refractory Systems

INDUSTRIES

  • Aerospace Industry
  • Aluminium Industry
  • Automotive and Mechanical
  • Defense Technology
  • Electronic
  • Glass and Ceramic Industry
  • High-Temperature Applications
  • Mechanical Engineering Industry
  • Metallurgical Industry
  • Non-Ferrous Metal Industry
  • Recreational Products
CARBON/GRAPHITE – FOR CHEMICAL RESISTANT LINING
BEARING AND SEALING – FOR MECHANICAL ENGINEERING

CARBON PRODUCTS FOR APPARATUS AND

REACTION VESSEL LININGS IN THE CHEMICAL INDUSTRY

STANDARD BRICKS

SHAPES

Standard dimensions for grades T/TX/TXH:
240 x 114 x 20, 30, 40, 50, 65, 80, 100 mm (stock sizes)
250 x 124 x 20, 30, 40, 50, 65, 80, 100 mm (on request)
Other thicknesses to 100 mm max. on request.
All other dimensions can be made and supplied under contract. These include bends, wedges, small plates, hand moulded bricks, support beams and tubes up to an external diameter of 600 mm.
(UNLESS OTHERWISE SPECIALLY AGREED)

a. Machined pieces e.g. tubes are manufactured in accordance with: DIN 7168 rough.

b. For special dimensions, e.g. hand moulded bricks no tolerances can be quoted and have to be agreed upon.

Besides the TYGRAF-T, TX and  TXH grades, other grades of carbon and graphite in the form of beams or tubes etc., for special chemical construction applications can be supplied. The technical data of these other grades are available on request. On principle, any size and shape can be produced. Moulding methods can be block pressing, extrusion pressing, vibrating and ramming. Hand moulded bricks, both complicated and simple in form are made in the TYGRAF-T, TX and TXH grades. It is recommended to contact us when projects in this field are being planned.

Special sizes and bricks with convex radii can also be made in suitable quantities. To allow us to check the feasibility of manufacture, both quantity requirements and dimensioned drawings should be supplied.

TYGRAF-T carbon bricks are extremely insensitive to all acids, provided they have no strongly oxidising properties. TYGRAF materials also show the same excellent resistance to attack by highest concentrations of alkaline solutions. Alternating acid and alkali conditions are withstood by this carbon material and they are also unaffected by corrosive salt solutions. TYGRAF-T carbon brick linings are thus particularly suitable for chemical processes which involve various temperature and concentration cycles.

The stability of TYGRAF-T, TX and TXH to various chemicals is given in the following table. It is pointed out that there is no difference in stability between TYGRAF-T and TX. Because of its higher density and lower porosity TYGRAF-TX is recommended in surroundings where erosion and oxidation occur. TYGRAF-TXH is impregnated with phenolic resin, and is resistant to oxidising acids up to 170° C. TYGRAF-TXH is unsuitable for strongly alkaline media.
In acid protection and apparatus construction the use of suitable cement is of the utmost importance. This is also important when using our CECOLIT bricks. In many cases the stability of our carbon and graphite material is greater than that of the cement used. Thus, when checking the stability and suitability of the possible carbon or graphite materials, the stability of the cement to be used in the particular application should also be checked so that full advantage can be obtained from the properties of our products.
In the choice of suitable cement, e.g. phenolic or furan resin based, we will gladly give our experience and advise on suppliers of cements, which we do not produce ourselves.

BEARING AND SEALING COMPONENTS
FOR MECHANICAL ENGINEERING

 
Carbon and graphite materials are a proven method for the sealing of shafts and their bearings.
The special physical and mechanical properties of carbon and graphite, in particular their low coefficient of friction, hard wearing and excellent thermal resistance offer solutions to many mechanical engineering and manufacturing problems.
Bearings, sealing rings and vanes made of carbon and graphite may be used for dry or wet running
applications. Their use is recommended where the following conditions prevail:
  • The use of hydro carbon lubricants is prevented by high operating temperatures
  • Oil or other lubricating contamination must be restricted
  • Chemical attack prohibits the use of other materials
  • Minimum servicing requirement
  • Dry running and high pressure demands a mechanically sound material with sufficient self-lubricating capability, good thermal conductivity and low coefficient of expansion
  • Bearings are situated vertically or at an angle in the machine thus making lubricant retention difficult
Bearings and sealing elements Supplied by TYNIC PA materials give the designer many opportunities for solving difficult bearing and sealing problems.

GENERAL APPLICATION INFORMATION

 

PHYSICAL AND MECHANICAL PROPERTIES
  • Good dimensional stability (low thermal coefficient of expansion)
  • Good heat conductivity
  • Good corrosive resistance
  • Good temperature resistance
  • Good self-lubrication
  • Good frictional characteristics
  • Good machining characteristics
  • Low weight
OPERATING TEMPERATURE
The temperature resistance in an oxidizing atmosphere can be specified as 500°C maximum for TYGRAF bearing qualities. In a non-oxidizing atmosphere the temperature resistance is determined by the final graphitizing treatment of each individual grade (e.g. upper application limit for graphite is approximately 3000°C). Temperature resistance is also affected by various impregnations. In the case of resin impregnation the maximum operating temperature is 180°C, for lead impregnation 200°C and antimony impregnation 500°C.
CHEMICAL RESISTANCE
Carbon and particularly graphite are characterised by excellent chemical resistance to almost all organic and inorganic media. Exceptions to this are some strongly oxidising acids, alkaline solutions, halogens and alkali molten metal.
FRICTIONAL BEHAVIOUR
Graphite has self-lubricating properties because of its crystalline structure. The low friction coefficient is a function of the low bonding between the structural lattice planes. Dislocation of one against the other is therefore easy. The friction coefficient is particularly low if traces of water or other vapours are present. The friction coefficient is greatly increased when a vacuum is created.
Because of the varying conditions of application, no exact data can be given for friction coefficients. In general the following values can be expected for sliding friction:
  • dry friction 0.10… 0.30
  • mixed friction 0.05 …0.10hydraulic friction 0.01 … 0.05
The frictional behaviour of carbon and graphite is also affected by the following factors:
  • running in
  • specific pressure
  • running speed
When running in carbon and graphite bearings, the friction coefficient drops until a constant value is reached once the surfaces are smoothed.
The coefficient of friction also drops in the case of constant specific strain and increasing running speed, or at the inverse.
CONSTRUCTION INFORMATION
The good machining properties of graphite give the designer full scope in producing practical designs.
 
The following guidelines should be observed:
Wall thickness: The choice of wall thickness depends on mechanical aspects. Based on practical operating experience, the graphite bearings should have wall thicknesses which correspond roughly to the empirical equation S = 0.13d + 2.8 ≥ 3 (mm)
Bearing length: To avoid excessive edge pressure and internal stress in the bearing L = d; L ≤ 2d is recommended. The height for washers is recommended as L = 0.1 D • L ≥ 3 (mm).
Flanges: Flange thickness b should be at least as much as wall thickness s (b ≥ s). Flange connections should be radiused and adjoining surfaces machined.
As a general rule: No sharp corners, should be broken or radiused. Shapes should be as simple as possible.
COUNTER FACE MATERIALS
suitable:
  • grey cast iron
  • plain steel
  • alloyed steel (chrome steel)
  • hard metal
  • ceramic
  • glass
suitable under certain conditions:
  • nonferrous heavy metal
  • chrome nickel steel
  • chromium plate materials
unsuitable:
  • aluminium and its alloys
SURFACE QUALITY OF THE COUNTER FACE MATERIALS

The surface quality of the counter face materials has an important influence on the durability of carbon and graphite. Counter face surfaces with a maximum surface roughness of Sr <1 μm are recommended. For high pressure lapped and superfinished counter faces with a maximum surface roughness of Sr<0.5 μm are necessary.

Tynic