At the heart of every tubular drag conveyor is the conveyor cable and disc or chain and disc assembly - the single most critical component in the system. Spiroflow offers a wide range of construction materials and assemblies to meet the demands of the various products being conveyed.
Selection of the cable or chain assembly recommended for any particular application is based on a number of factors: The total length of the conveyor circuit, the number of casing bends, material loading, the total mechanical load (cable/chain pull), the number of planes the cable or chain will pass through and the characteristics of the product being conveyed. Spiroflow offers two types of cables and several chain assembly options to insure proper operation across a wide range of applications.
Our cable and disc assemblies are a development of those used in our range of aero mechanical conveyors. The cables are sized to withstand the load imposed upon the discs. The discs are injection molded directly onto metal ferules that are rigidly crimped along the length of the cable. Cables are made from carbon or stainless steel according to the application.
The 304 stainless steel chain is fitted with 4" (100mm) diameter molded food grade UHMWPE discs every 5" (125mm). Molding the discs directly onto the chain minimizes crevices where material can accumulate. The chain can be upgraded to 316 stainless steel.
Elastomer washers are compressed around the pins and between the links to seal abrasive and corrosive materials from the pin bearing surfaces maximizing chain life. Seals are most commonly made of neoprene. High-temperature seals are used for high high-temperature applications and PTFE (Polytetrafluoroethylene or Teflon) seals are used for corrosive or abrasive applications. Other seal materials are available upon request.
This chain style utilizes commercially available #348, #458 and #678 drop forged rivetless chain with open pin construction. This type of chain is extremely durable and less costly than the sealed pin variety.
Surprisingly Dynaflow chains are designed to rotate out of plane up to 90 degrees over a given distance. This means that universal joints, with their inherent drawbacks and added expense, are not required. Our chains are constructed to allow elements or sections to be replaced when necessary.
Conveyor disc selection is another critical point. The proper disc material must be chosen to withstand possible chemical attack, abrasion, temperature, etc. Spiroflow Systems offers an effective range of standard discs to meet the needs of virtually any application:
Ultra High Molecular Weight Polyethylene (UHMWPE): This is generally the most popular and best all-around disc material, due to its extremely high abrasion resistance, very low coefficient of friction, high impact strength and resulting long service life. The material is available in a FDA approved grade that is chemically inert and water resistant. UHMWPE has a service temperature is up to 176°F (80°C).
Cast Iron: This is the second most popular flight material due to its low cost and reasonable service life. When corrosion, abrasion, chemical resistance and product contamination are not a factor cast iron can be a prudent choice of materials. In some applications, mild steel may be substituted to provide the same type of service. Cast iron and mild steel flights have a service temperature up to 480°F (250°C).
Other Materials: While nylon and polyurethane discs do not offer all the beneficial properties of UHMWPE there are applications where these materials are recommended.
Special Materials: Conveyor flights can be molded/cast, machined, fabricated or flame cut from a wide range of materials as required by a specific application. A Spiroflow Systems engineer can recommend the best flight material for your application.