High-specification Carbolite ovens have been installed by specialist seal provider Greene, Tweed and Co to increase the capacity and consistency of the raw material sintering operation at its UK plant

Two high-specification Carbolite ovens have been installed by specialist sealing solution provider Greene, Tweed and Co to increase the capacity and consistency of the raw material sintering operation at its UK manufacturing facility. Greene, Tweed is a world leader in the supply of polymer-based engineered solutions to market leaders in industries such as defence, aerospace, chemical processing, medical equipment and oil and gas production and has been experiencing growing demand for its products. The company uses a wide variety of proprietary PTFE formulations for its products, which are moulded in tube and bar form in the facility before being sintered and then machined to the custom designs required by customers.

The two new ovens, which join two existing units that have been in the factory for over ten years, have a maximum volumetric capacity of 1.73m3 and can operate to 425C maximum.

Temperature uniformity is guaranteed to be better than +/-5C and is typically only +/-3C.

The tube and bar being processed stand on rotating tables, ensuring that heat is applied very evenly to all the material.

The tables, which are perforated to improve air circulation throughout the chamber, rotate approximately once every two minutes.

Heating is provided by Incoloy-sheathed, mineral-insulated rod elements located behind side duct sheets, with air being circulated by heavy-duty fan impellers on either side of the chambers.

A typical sintering programme takes up to 20 hours, with time and temperature being controlled by a high-quality digital programmer supplemented by an over-temperature cut-off.

In addition to the thermocouples linked to the control and over-temperature instruments, nine floating thermocouples are linked to the company's own computer system to provide real-time read-outs and hard-copy records of the temperatures throughout each chamber during a processing cycle.