Heating/cooling: All under control

A move away from steam heated platen presses to a thermal fluid heating and cooling system at TRB Lightweight Structures has produced a range of benefits, as Chris Horsley, MD of Babcock Wanson, explains

Established 60 years ago, TRB Lightweight Structures is a leading OEM for the rail, aerospace, defence and marine industries, designing and manufacturing tailor-made lightweight solutions and bespoke fabricated assemblies, including train doors and aircraft galleys.

Barry Kimber, the company's facilities manager, has been integral in ensuring the manufacturing facilities and processes at the site are maintained at peak efficiency together with meeting the developing needs of the business.

Kimber explains his decision to replace the steam heating system: "When I joined TRB, we were using two steam generators to heat the presses, with water cooling and condensate return systems. The water in a steam system can become corrosive as acid builds up in the condensate, which can lead to damage in the pipework, and although we had converted to stainless steel pipes, we were always aware of the potential environmental impact. The boilers were old and were becoming expensive to run and, conscious of the possible safety issues of using an 8 bar steam process, we made the decision to investigate other systems." For TRB, maintaining a constant temperature control was crucial to providing a consistent quality of product especially with some of the high performance resin systems being processed. The steam system did not provide a constant temperature without strict operating guidelines and was labour intensive: "Without careful management, we would have had insufficient temperature control; the temperature could drop off, which is something you don't get with thermal fluid heaters. We had to closely monitor the temperature ramp up - as the steam valves were opened, it could get very hot very quickly which could impair our process. The thermal fluid system provides measured ramp up temperatures and also a controlled cool down over a set time which can be important with many of the latest adhesives and resin systems." TRB fitted a Babcock Wanson TPC600B fully automatic coil type, multi-pass thermal fluid heater complete with integrated burner, control system and safety devices. A single fluid - Paratherm MR - is used throughout the system which has a very flat viscosity curve so is readily able to switch between heating and cooling functions.

While the change from steam to thermal fluid heating has made improvements in production efficiencies and output, TRB has gone one step further. Utilising Babcock Wanson's new menu driven software, TRB now has the facility to create up to 50 programmes for the heating/cooling system.

Kimber explains: "This new software allows us to enter up to six stages per profile, so we can include the ramp up temperature and time, platen temperature, cook, cool down and dwell at the end of a cycle. It's very flexible. We have approximately 10 programmes as standard but with the extra capacity and capability, R&D is exploring the use of other raw materials, which will continually drive the company to find new market areas." This is made all the easier with the software taking automatic readings every six seconds. The data is readily retrievable by simply downloading onto a flash drive.

Statistical information is then available in a variety of formats, including clear graphs.

The software operates the Babcock Wanson Temperature Control Units on each press. They are connected to both the heating and cooling distribution loops to automatically feed the hot and cold fluid to each press as and when required meaning that each part of the line can be at a different part of the thermal cycle at any given time.

Kimber adds: "Control of temperature is very important to the product and therefore to the business as a whole. With the new system and software, we can be highly accurate with the temperature control which not only increases the range of products the company can process but also considerably increases panel capacity.