Optional Equipment for Tube Furnaces

A wide range of sizes are available in various grades and types of ceramics.
Additionally quartz silica and heat resistant metal tubes can be supplied.

These are for use with worktubes when working in controlled atmosphere or vacuum environments.

Three basic designs are available:-

• Universal End Seals - This system can accommodate wide tube O/D tolerances and is comprised of:- a blanking plate, a flat Viton seal and a worm screw with clips.
• Screw-On End Seals - This system is more suitable to close tube O/D tolerances and is comprised of:- a two part machined flange with an 'O' ring seal.
• Triple Flange End Seals - This system is designed to simplify loading/unloading procedures and to provide a more efficient seal for high vacuum applications - This system is comprised of:- a three part machined flange with two 'O' ring seals.

All three designs can be fitted with a variety of connections for use with gas or vacuum.

These items are used to reduce heat losses from the ends of the tube and also to reduce the possibility of the tube cracking due to thermal shock.

Vacuum processes require the radiation screens to be made from non-porous ceramic or metal.

A flowmeter(s) with control valve can be supplied for use with air or inert gases. The flowmeter(s) can be used in conjunction with gas inlets, retorts/liners and worktubes with gas tight end fittings.

There are two standard system types available which provide timed purging and full gas monitoring. Both systems are designed for use with Hydrogen and other flammable gases.

Supplied for use with inert gases, comprising of a simple hose spigot and tube projecting into the furnace/oven chamber to provide reduced oxygen levels.

A full range of operator safety equipment is available, which includes visors, gloves approns and tongs.

Alternative control system configurations designed to improve temperature uniformity in large chamber furnaces with densely packed loads.

a) Multizone Control System

The chamber temperature uniformities in furnaces having larger chambers, mainly Industrial and Light Industrial types can often be improved by having multiple control zones, thus ensuring that a greater part of the working area is within acceptable temperature limits. Multizoning can be applied to several of our larger models. Consult our sales engineers for further details.

b) Cascade Control

In applications where the load is comparatively large and densely packed, wide temperature gradients can occur between the centre and outside of the load when using a single temperature controller, especially when the treatment cycle is of short duration. This can adversely affect product quality.

Cascade control operates by having 2 temperature control loops working together; one measuring the temperatures within the load and one controlling heating element temperature.

The load thermocouple/controller ensures that the centre of the load achieves required temperature by driving the element controller to deliver sufficient power to the heaters, but simultaneously maintaining the element temperatures within acceptable limits to prevent overheating of the outside of the load.

This provides an independent thermocouple for use in conjunction with either a digital temperature indicator or a chart recorder.

The digital indicator, or chart recorder, can be integrated into the furnace casing or be housed in a separate console.

In applications where gas tight end seals are fitted a viewing port can be fitted in one/both ends of the end seals. The viewing port could be covered with a simple metal flap or with clear or tinted glass.

A variety of stand options are available to provide horizontal, vertical or fixed/variable angled positioning.

Where the equipment needs to be transportable there is a choice of various wheeled trolley systems.