High performance heat transfer rolls

BEP specialises in the design and manufacture of high performance Heat Transfer Rolls (also known as Heating & Chill/Cooling Rolls) for many industrial applications.

Heat transfer Rolls provide temperature control by circulating heated or cooled fluid through the inside of the roll chamber. Roll design and configuration of the internal spirals plays a major in the performance of the rolls. Many Thermodynamic and mechanical factors are considered.

BEP can advise on design and method of manufacture of your rolls to ensure you obtain optimum performance and efficiency.

Chill Roll Refurbishment

BEP Surface Technologies has the expertise and technology to refurbish rolls of all sizes up to 1500mm diameter and weighing 10 tonnes.

It can cost up to £40,000 to replace a large steel cooling roll and £80,000 for a new copper shelled chill roll. Refurbishment charges can amount to less than 30% of the cost of purchasing a new roll from an OEM. On large copper shelled rolls refurbishment can save over 80% against new.

Precision rolls used in plastics sheet and film manufacturing processes generally work in sets of three and because they can run with only microns, separating their concentricity is absolutely critical. Coater rolls used in laminating processes require similarly fine tolerances. BEP’s techniques guarantee maintenance of the structural integrity of rolls and repeatability of the original chrome finish (RA: Roughness Average), TIR (Total Indicator Reading) specifications and tolerances to ensure rolls work first time on re-installation.

Another significant benefit is reduction in down time. Refurbishment is considerably quicker than buying new. BEP undertakes all the necessary processes in-house and can refurbish a roll in 15 working days, compared with 90 days for the manufacture of a new roll.

Copper Shell Chill Rolls

COPPER SHELLED CHILL ROLLS HAVE THE CAPABILITY TO PRODUCE MORE PRODUCT FOR THE SAME FLOOR SPACE, USE LESS ENERGY AND SOLVE CONDENSATE PROBLEMS.

  • Greatly increased Line speeds
  • 10 times the thermal efficiency of steel rolls
  • Reduced cooling costs
  • Lower energy consumption
  • Elimination of condensation on roll ends
  • Repeatable high quality finishes

 

HIGH EFFICIENCY COPPER CHILL ROLLS

BEP has more than 250 high performance copper chill rolls in circulation around the globe.
Many of the world’s leading laminators, cast film producers and high quality textured paper manufacturers have chosen to invest in our rolls because they produce higher quality products, at greater speed, using less energy.

In 2002, we observed that our clients were unable to operate their production lines at optimum levels of performance due to the inherent limitations of both steel and aluminium chill rolls. This led us to design our first copper chill roll product.

We are experts at electroforming high quality, seamless copper tubes to any thickness our clients specify. Our unique method of manufacture delivers the best combination of heat transfer and roll rigidity.
With coppers anti – corrosive qualities and high thermal efficiency, our rolls were a natural choice for companies who wished to increase their line speeds, improve their product quality and reduce their operating costs.

An additional unforeseen benefit of selecting copper shelled chill rolls was that our clients became able to reduce their capital expenditure on other components within their manufacturing lines.

BEP’s unique proposition allows us to replace an outer steel shell with a fine grain electroformed copper shell, up to 20mm thickness depending on application, which we then shrink fit over stainless steel guiding spirals welded to an inner core. This provides great strength and enhanced resistance to deformation.

WHY USE COPPER?

We use copper because its thermal coefficient of heat transfer is 10 times that of steel. This means that during the time the copper shell is in contact with PE it can absorb up to 10 times more heat. This can dramatically reduce the contact time compared with steel rolls, hence allowing the line to operate at greater speeds.

CHILL ROLL COOLING ENERGY SAVINGS

Engineering experts have confirmed that for every 1°C increase in cooling water temperature, a 5% saving in energy costs can be delivered. Therefore a copper chill roll operating at 20°C can deliver the same performance as a steel roll operating at 10°C, whilst still offering you the potential to reduce your refrigeration costs by up to 50%.

Operating chill rolls at 20°C also means that in high humidity climates, condensation does not build up on the cold ends of the roll, thus reducing product waste.

Calendar / Hardened Rolls

Calender rolls are used for Calendering or “Smoothing” and are used in Extrusion, Laminating, Coating, Stretching, Polishing and Embossing.

Our Calender rolls can be manufactured from Single or Double Shell design and are hardened to around 54Rc. The Roll body is made from 42 CrMo4 steel and is tempered, stress relieved and hardened. The rolls are normally finished in Chrome and are Super Mirror Finished by BEP in our workshop.

Degassing

Heated chrome rolls used in the plastics industry normally require heat treatment to remove occluded hydrogen from the chrome deposit. If this is incorrectly managed the hydrogen can percolate out of the chrome and cause defects in the form of tiny bubbles in the plastic sheet or film.

To save customers wasting production time pre-heating the rollers in their machines prior to use we can treat rolls in a specially constructed temperature controlled oven. We heat the rolls to a precisely controlled thermal ramp and record the temperature profile data. During the heat treatment process the rolls are hung vertically to eliminate any risk of distortion.

Thermodynamic

BEP has developed an in-house thermodynamics modelling tool to help our customers better understand how their product heats up or cools down when in contact with the heat transfer roll.   It is most commonly used with laminating rolls but is flexible enough to model other scenarios such as oil heated rolls or more specialist applications.   Whether you are considering upgrading from a steel to a copper roll or are looking to optimise your existing process we are happy to help.   [Link to enquiry form/download]

Internal Cleaning

Users of cooling and heating rolls may experience problems with roll waterways becoming furred up with either lime scale or rust. Providing the waterways are not completely blocked and the rust has not corroded through the shell we can usually clean them out.

The process involves pumping a temperature controlled cleaning solution, specially developed by BEP, through the waterways to dissolve the lime scale and rust, thus restoring the rollers to their original thermal efficiency.

After cleaning any residual acidity is neutralised and the roll is thoroughly washed out with water and flushed with a rust inhibitor.

All the residual chemicals from the cleaning process pass through our effluent treatment plant before final discharge to sewer.