DELONG INSTRUMENTS a.s.

The furnace is intended for vacuum annealing and soldering.
Being made of austenitic stainless steel, the furnace features a double-jacket design; the inter-jacket space is flown through by cooling water. The furnace top cover accommodates a sight glass and two water-cooled vacuum-tight power-cable bushings. The furnace bottom cover is provided with two vacuum-tight bushings for thermocouple lead-in wires and a junction piece for the pumping unit valve. The top and the bottom covers are water-cooled, too.

The top cover and the jacket make up a bell in which a heating cage is mounted. The bell is sealed against the bottom cover by an O-ring. It can be lifted by means of a manually operated lifting gear.

The heating cage consists of an upper and a lower molybdenum annular ring systems and molybdenum heating rods, which are insulated by alumina rings. The space between the heating cage and the vacuum chamber water-cooled jackets is filled with five radiation-shielding layers, which are made of molybdenum, too.

A programmable controller, allowing easy programming of heating cycles, controls the low-voltage current heating system operation. Two independent thermocouple thermometers are used to measure the temperature.

A pumping set, consisting of a turbo-molecular pump and a membrane pump, provides vacuum in the chamber. The furnace operating chamber is insulated from the pumps by means of a slide valve; an anti-vacuum valve serves to fill the chamber with air or inert gas. Pirani and Penning gauges are used to measure the pressure.

The furnace cooling is provided by a steady flow-through of tap water, whose flow rate is measured by a flow meter.

Reliability, simple design and low space and power requirements are the most decisive advantages of this furnace.