TEMPERATURE CONTROL FOR SF-16 FURNACES

Temperature control systems are designed for controlling the heat output of furnaces, chambers and ovens, as well as controlling the cooling of chambers when connected to a liquid nitrogen source. The control systems are offered for use with new creep, stress rupture or hot tensile systems, or they can be added to an existing frame using an existing furnace or chamber (not intended for use with 3117 Series furnaces or 3119 Series environmental chambers). The control system can either be built into a panel that is part of the frame itself or provided in a standalone cabinet to house the controls, electronics and cabling connections. The systems may be configured for use with either a manual or automatic gradient adjustment. The control systems are compatible with all furnace systems offered as new equipment, and can be configured to operate nearly any furnace, chamber, or oven with any one of several different thermocouple types. Three-zone control systems are designed for heat-only furnaces with three separate zones of heating elements, and typically three different thermocouples to control those zones. Single-zone control systems are designed for heat-only furnaces with one zone of heating and one thermocouple. They can also be set up to control both a heating and cooling function for chambers that have both heating elements and a piped, solenoid controlled connection for liquid nitrogen using a single thermocouple.

Principle of Operation

Typical systems consist of either one or three model 2416 Eurotherm® controllers. Each controller independently controls the temperature of a furnace/ chamber zone. Automatically controlled systems allow the user to program a set-point or test temperature, and the controller controls a zero-cross fired SCR to control the current to each zone. Manual systems use a single 2416 controller for temperature indication and control, while allowing the operator to adjust the gradient to each zone through use of three powerpositioning potentiometers. Standard systems use Type-K thermocouples to monitor temperature either from the furnace wall or attached to the specimen. Other types of thermocouples can be substituted, if specified at the time of order. Zero-cross SCRs are used for stable high current control of power going to the furnace/ chamber heating elements. The electrical isolation and heat sink cooling design offers long life and stability, which is very important for long material testing applications.

Application Range

• Provides the ability to control single-zone and threezone furnaces of many different types

• Can be configured to control both heating and cooling functions of an environmental chamber