Mechanical Products

Carbon Vanes

Assam Carbon vanes are made in the range of carbon materials (carbon graphite, metal-impregnated carbon graphite and resin-impregnated graphite) to meet many different application requirements. All Assam Carbon grades retain the basic properties which make Carbon unique as an engineering material and particularly suited for vanes which may operate in conditions beyond the limits of other materials.

Self-Lubricating

Carbon vanes are self-lubricating and therefore, ideal for pumps, handling liquids such as petrol which has poor lubricating properties. They can also operate in unlubricated compressors to deliver air or gas uncontaminated by lubricating oil or grease, in which case Carbon gives a fine polish to the cylinder wall which reduces the wear rate of the vane after bedding almost negligible proportions.

Fine Tolerance & Surface Finish

Even at 400°C thermal expansion in Carbon is minimal (they are also non- hygroscopic and do not swell after immersion in hot or cold water) the vane clearance in its rotor slot can therefore be fine. A tolerance of ±0.02 mm can be maintained in bulk production.

Chemically Inert & Non-Toxic

Carbon vanes are chemically inert and non-toxic and cannot contaminate the liquid or gas being handled. They can safely be used in food-processing equipment and in other fields where purity is essential. Carbon vanes are totally unaffected by water (pure or salt), most acids, alkalis or oil solvents such as petrol or paraffin. In these conditions, the liquid can reduce friction and wear by providing lubrication between vane and rotor slots and vane top and cylinder wall.

High Mechanical Strength

One of the most important requirements for vane materials is high mechanical strength. Carbon vanes meet this requirement. Their strength is indicated by the pressure regularly handled, which ranges from 3.2 kgf/cm2 down to high vacuum conditions, with peripheral speeds up to 12.7 m/sec.

Design

These should be of robust proportions and of simple design, if possible rectangular in shape. Two main forces act onto vanes and tend to bend them in their slots.
1. Differential pressure across the thickness.
2. Bending movements caused by tip friction against the cylinder wall. For small vanes lightly loaded, thickness of 3.2 mm has been found adequate, but thickness up to 9.5 mm should be adopted for larger sizes and where the differential pressure is likely to be high.

The chart given is a general guide to the preferred dimensions for vanes. Vanes can, however, be machined to customers' specifications, provided that the proportions are acceptable from the design, as well as from the manufacturing point of view.

   

Cylinder & Rotor Materials

It is important to use the correct cylinder material for smooth operation with carbon vanes. Possibly a corrosion- resistance and hard metal should be used. Surface should be fine ground and honed. Rotary slot should be well finished and free from any burr.

Major Applications

  • 1) Air Pumps for the printing industry.
  • 2) Spray paint equipment
  • 3) Packing machinery
  • 4) Food processing equipment
  • 5) Wet running vane pumps and meters
  • 6) Automotive diesel fuel pumps
  • 7) Drink vending machines
  • 8) Fuel tanker meters
  • 9) Air Pumps for the printing industry
  • 10) Aircraft fuel tank metering



Ascarbon Morgan is dimensionally stable both through a wide temperature range and in a variety of fluids. Very find vane-to-rotor slot clearances may, therefore, be set and maintained, thus ensuring maximum efficiency. A grade that has found wide acceptance in the high duty market is HYX67 which is a resin-bonded material having a high impact strength and low friction. It is capable of operating under extreme conditions with the minimum of wear.


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