AP Braking Ltd., Warwickshire, U.K., has expanded and upgraded its research and development facilities with the installation of a specially modified Carbolite thermal chamber suitable for long-term test programs involving flammable liquids.

From Carbolite, in Hope Valley, U.K., and Watertown, Wis., the new equipment is an upgraded version of an existing chamber used by the company for several years. It is designed to accept rigs for thermal-stroking tests on components such as brake cylinders and calipers. These components can incorporate a number of metals and plastics as well as various fluids and greases.

Thermal-stroking tests are carried out by attaching components to jigs fixed inside the chambers with hydraulic piping passing through the oven walls to external actuators. Up to four components can be tested at one time. A typical Society of Automotive Engineers test requires brake cylinders to be subjected to 1,000 strokes per hour for 70 hours at a temperature of 248°F (120°C) to simulate conditions in an engine compartment.

The chamber has a maximum temperature of 392°F (200°C) and can be programmed to provide temperature cycling if required. It is integrated with the test rigs, so the chamber automatically switches off if a fault develops. An explosion-relief panel also is fitted.

Should a component fail, surfaces that could come into contact with flammable liquids are below their autoignition temperature, and elements are positioned away from flammable vapors. The chambers also are sealed to prevent liquid escaping. Internal lighting has been fitted so that staff can see clearly while they are setting up equipment.