Peristaltic pumps from Watson-Marlow Bredel were specified to handle sand-based gel for a project that dealt with autumn leaf fall problems for Network Rail.
A specialist in supplying rail maintenance equipment, Portec Rail Products (UK) Ltd was approached by Network Rail to manufacture a trackside traction gel applicator that would break down the cellulose film generated from crushed leaves.
Watson-Marlow Bredel peristaltic pumps were specified as part of this project to handle the sand-based gel called Sandite to be applied using the trackside applicator onto the head of the rail.
The pump is a critical component of the applicator and needed to handle the gel and the harsh environment.
After carrying out trials using multiple pump types including impeller pumps, Portec Rail Products found that they were unable to cope with the sand slurry that formed part of Sandite.
Unlike other pumps, the Watson-Marlow 701R peristaltic pumps could handle the fluid without difficulty, says Chris Twigg, Manager at Portec Rail Products (UK) Ltd.
Traction control is a big issue in the autumn, particularly when braking and accelerating on the railway tracks.
Maintaining grip on the line is especially important when approaching and departing from a station, making total reliability from all components in the applicator essential.
Previously, crushed leaf deposits on Network Rail's lines had been dealt with by a special Sandite train that would travel the length of the track, depositing the abrasive gel in known areas of low rail adhesion.
On busy lines though, the effect of the gel on the track is lost after a number of trains have passed over it. But a trackside applicator can be used to apply Sandite each time a train approaches.
The trackside applicator consists of a cabinet located five to six metres away from the line, which is linked to an induction wheel sensor attached to the track.
The sensor recognises an approaching train and signals a controller in the cabinet to actuate the 701R peristaltic pump.
The 701R pumphead draws Sandite from an integral storage hopper in the cabinet and pumps it to spreaders clamped onto the field side of each railhead.
The gel then flows out of the spreader's 6mm holes onto the railhead to form a pool of Sandite that is transferred by the train wheels down the track. The gel combined with the pressure of the wheels breaks down the leaf material.
Explaining the reason behind specifying Watson-Marlow pumpheads for the project, Andy Scobie, Weather Strategy Manager from Network Rail said that they had previously used the pumps on a similar application successfully with good results.
Although the trackside gel application units are only used for ten weeks of the year, they play a vital role in keeping the trains running on time.
Positioned in leafy areas and places with a history of low rail adhesion, they provide a simple solution to the familiar problem of delays associated with leaves on the track.
Watson-Marlow 701R pumpheads feature driven rollers to provide smooth, low pulse flows up to 2000 litres/hour at 360 rpm, and can accept tubes in five different sizes and seven materials to cope with a wide range of fluids.