On Site Installation of Teflon* Sleeves to Drying Cylinders

In many cases, it is impractical or impossible to remove Drying Cylinders from the Paper or Textile machine, so Holscot developed the ability to carry out the installation of the Teflon sleeves whilst the cylinder remains in the machine. Using sophisticated welding techniques, the sleeve can be seamed on site.

The "in-situ" installation procedure is outlined below.

Alternatively Sleeves can be fitted to cylinders out of the machine provided rotation facilities and steam are available.

1) Preparatory Work by Customer:-

The cylinder should be cleaned to a bright metal surface. Ancillary equipment in the immediate environment such as rollers, doctor blades and felts should be removed.

A support bar must be mounted over the cylinder, walkways must be supplied to gain access and extra lighting may be needed if the cylinder is not illuminated.

2) Welding the Sleeve

The sleeve in sheet form is wrapped around the prepared cylinder and supported from the overhead support bar.

The top part of the Holscot welding equipment is introduced via side access and secured to the support bar.

The bottom part of the welding machine is then brought in and all relevant connections put in place.

Both ends of the sleeve are secured onto the lower welding bar then the upper welding bar is positioned onto and secured. The joint is then fused. Depending on the face width of the cylinder and the length of the welding bar this operation will need to be repeated until the sleeve has been welded into a complete cover.

3) Shrinking the sleeve

Welding equipment is withdrawn, steam is let into the cylinder to provide background heat and the sleeve is shrunk down using a large 440v 3 phase hot air gun.

4) Bonding the sleeve

Adhesive is injected under the cover and spread over the entire surface of the cylinder.

5) Finishing off

The cylinder is then heated to approximately its working temperature whilst revolving slowly and continuously so that final curing of the adhesive can take place.

The duration of the installation depends on the size of the cylinder but the entire procedure is unlikely to take less than 8 hours.