Machine shops save time with a Paragon HT22D furnace at their disposal in their own shop. You will no longer send a die out for heat treating, wait for its return and then send it out again for additional heat treating.
The door of the Paragon HT22D swings open with one-handed operation. A counter-weight handle holds the door securely closed. The door has a vent hole, so you can see inside the furnace during firing. Metal covers seal the vent holes when not in use. (Always wear Paragon firing safety glasses when looking into a hot furnace.) The furnace is insulated with refractory firebrick. The elements are mounted in dropped, recessed grooves machined into the firebrick. Paragon invented this type of groove in 1952. This groove protects the element for long life and low maintenance. Elements are simple to replace because they’re exposed rather than embedded. You can thread new elements into place following clear instructions in the manual.
The firing chamber is protected by a steel case painted in high-temperature blue. A built-in stand lifts the firing chamber safely off your worktable, so no extra stand is needed. The door is mounted with a heavy-duty hinge for smooth opening. A micro-switch shuts off the power to the elements when the door is opened. We use high-temperature wire in the switch box for long life. A heat shield, mounted between the switch box and furnace, helps keep the switch box components cool even during extended operation. To further dissipate heat, the switch box is extra large and generously louvered.
During heat treating, scale forms on the surface of the steel. One way to eliminate most scaling is to wrap the steel in stainless steel foil, which Paragon sells. An easier way is to install the gas injection flow meter on your furnace. It is available as either an add-on kit, or you can order the furnace with the meter installed.
The meter regulates the flow of an inert gas, such as argon, inside the furnace. The gas displaces the oxygen to prevent most scaling.