New Heat Treatment Facility

Mannings Thermal & Environmental Engineers of Southport have announced the completion of a new purpose built energy efficient heat treatment furnace at the Midlothian works of MacTaggart Scott & Co. Ltd. The furnace, which is fired by natural gas, is designed to produce temperature uniformity within very tight limits, so that a variety of metal components can be stress relieved to a high standard, in the minimum amount of time.

MacTaggart Scott & Co. Ltd is known all over the world as designers, manufacturers and installers of hydraulic machinery. Their range includes winches and motors for the mining industry as well as specialised marine hydraulic equipment. Before the installation of the new heat treatment furnace, it was necessary to subcontract the stress relieving of critical components. Works Manager, Jim Stewart said "the purpose of the new facility is to give us direct control over quality, improve production and reduce costs at the same time".

The furnace is a Roller Cover type, which was installed into an existing production line. The furnace base and one of the end walls are permanently fixed in position. However the furnace cover is mobile so that it can be moved to allow clear access for loading the parts to be heat treated, and unloading the finished items. The cover is mounted on rails, which ensures accurate positioning and powered movement is by means of an electric drive motor.

Loads of up to five tonnes can be treated and the fu from heavy-duty 1000 degrees centigrade and the heated zone can be kept to a minimum size. As an added safeguard, over temperature. The furnace cover has a steel superstructure and is internally insulated with lightweight, low thermal mass ceramic fibre and mineral wool, secured by special heat resistant fixings. This construction saves energy by permitting rapid heating and cooling.

The heat source is from two, low-level nozzle mix gas burners arranged to fire in parallel. These burners are modulated in response to a signal from a plc in the control panel to achieve the desired set temperature. The temperature is extensively monitored by sensing devices to ensure maximum efficiency. A high temperature re-circulation fan has also been incorporated into the design to produce turbulence within the furnace and maintain the uniform heat distribution.

The control system is housed in a wall-mounted panel which contains the programmer, alarms and safety interlocks. The fully automatic controller has a multi-ramp facility and a large number of setting can be selected to match the particular furnace load.

Mannings specialise in heat treatment processes and this furnace was specifically designed and built to suit the application. Les Oliver, who is Mannings Industrial Process Heating Manager said, "the energy saving features of our furnaces are being continually developed and this particular unit is a cost effective addition to the production line for MacTaggart Scott"