Abstract: A vacuum heat treating furnace for the heat treatment of metal parts includes a pressure vessel and a hot zone enclosure that defines a hot zone therein. A heating element array inside the hot zone enclosure includes a first heating element, a second heating element, and a center heating element. The first and second heating elements are suspended on opposing sides of the hot zone enclosure. The center heating element is suspended vertically from the hot zone enclosure between the first and second heating elements. The center heating element is adapted to be connected to the first and second heating elements to form a continuous circuit therewith. The center heating element may be connected to the first and second heating elements with removable/reusable fasteners to provide for reconfiguration of the hot zone to accommodate different size workloads.

Abstract: A load transport mechanism for moving a heat treating load in a multi-station heat treating system is disclosed. The transport mechanism has a compact construction that allows it to fit in a centrally located stationary transport chamber. The transport chamber is adapted to provide ready access to multiple treating chambers arrayed around the chamber. The transport mechanism includes a load translation mechanism for moving the load linearly and a load rotation mechanism for rotating the load within the transport chamber. A multi-station heat treating system having a centrally located quenching chamber that includes the load transport mechanism is also disclosed.

Abstract: A process for quenching heat treated metal parts using a liquid quenchant and high pressure is disclosed. In general, the process includes the steps of providing a load of heat treated metal parts in a pressure vessel wherein the load is at an elevated temperature after being heat treated. In a subsequent step, a liquid quenchant is injected into the pressure vessel such that a vapor of the liquid quenchant forms rapidly in the pressure vessel and cools the metal parts. The step of injecting the liquid quenchant into the pressure vessel is continued for a time sufficient to establish a desired peak vapor pressure in the pressure vessel. An apparatus for carrying out the disclosed process is also described.

Abstract: A lifting apparatus for a vertical vacuum furnace is disclosed. The apparatus includes first and second support modules arranged in spaced parallel alignment and first and second reversible lifting mechanisms mounted on respective ones of the first and second support modules. The apparatus also includes first and second motive means coupled to the first and second reversible lifting mechanisms for driving the reversible lifting mechanisms. First and second trolleys are operatively connected to the first and second reversible lifting mechanisms and adapted for engaging with a payload. The apparatus further includes a control system connected to the first and second motive means for controlling the operation of the first and second reversible lifting mechanisms whereby the first and second trolleys can be raised or lowered. A vertical vacuum furnace assembly including the lifting apparatus is also disclosed as well as a support module and a bottom head assembly for the lifting apparatus.

Abstract: A vacuum heat treating furnace for the heat treatment of metal parts includes a pressure vessel and a hot zone enclosure that defines a hot zone therein. A heating element array inside the hot zone enclosure includes a first heating element, a second heating element, and a center heating element. The first and second heating elements are suspended on opposing sides of the hot zone enclosure. The center heating element is suspended vertically from the hot zone enclosure between the first and second heating elements. The center heating element is adapted to be connected to the first and second heating elements to form a continuous circuit therewith. The center heating element may be connected to the first and second heating elements with removable/reusable fasteners to provide for reconfiguration of the hot zone to accommodate different size workloads.

Abstract: A process for quenching heat treated metal parts using a liquid quenchant and high pressure is disclosed. In general, the process includes the steps of providing a load of heat treated metal parts in a pressure vessel wherein the load is at an elevated temperature after being heat treated. In a subsequent step, a liquid quenchant is injected into the pressure vessel such that a vapor of the liquid quenchant forms rapidly in the pressure vessel and cools the metal parts. The step of injecting the liquid quenchant into the pressure vessel is continued for a time sufficient to establish a desired peak vapor pressure in the pressure vessel. An apparatus for carrying out the disclosed process is also described.

Abstract: A furnace for heat treating of metal parts includes a hot zone enclosure defining a hot zone therein. The hot zone enclosure has a side wall, a first end wall, and a second end wall. The side wall has slots formed therethrough and along the length thereof. The heat treating furnace also includes a system for injecting a cooling gas into the hot zone through the hot zone enclosure. The heat treating furnace further includes a damper arrangement for directing the cooling gas over a selected portion or portions of the workpiece load and through one or more of the slots. In one embodiment of the invention, all actuated components in the furnace are located outside of the hot zone to minimize damage to moving parts that are caused by exposure to extreme heat.

Abstract: A convection heating system includes a hot zone enclosure defining a hot zone and a plurality of gas injection nozzles for injecting a cooling gas into the heat treatment zone of furnace. Each gas injection nozzle may include a flap disposed and pivotally supported therein for substantially preventing the escape of heat from the hot zone during a heating cycle, but for permitting the injection of the cooling gas into the furnace hot zone during a cooling cycle. A gas exit port may be provided and may include a flap pivotally mounted therein for impeding the unforced outward flow of a gas from the heat treatment zone during a heating cycle.

Abstract: A furnace for heat treating of metal parts is disclosed. The heat treating furnace includes a hot zone enclosure defining a hot zone therein. The hot zone enclosure has a side wall, a first end wall, and a second end wall. The side wall has slots formed therethrough and along the length thereof. The heat treating furnace also includes means for injecting a cooling gas into the hot zone through the hot zone enclosure. The heat treating furnace further includes a novel damper arrangement for directing the cooling gas over a selected portion or portions of the workpiece load and through one or more of the slots. In one embodiment of the invention, all actuated components in the furnace are located outside of the hot zone to minimize damage to moving parts that are caused by exposure to extreme heat.

Abstract: A nozzle for injecting a cooling gas in a vacuum heat treating furnace is described. The cooling gas injection nozzle according to the present invention has a forward portion with a first central opening formed therethrough. The cooling gas injection nozzle also has a rear portion with a second central opening formed therethrough. A flap is disposed in and pivotably supported in the first central opening. The flap operates to substantially prevent the escape of heat from the hot zone during a heating cycle, but permits the injection of the cooling gas into the furnace hot zone during a cooling cycle. The cooling gas injection nozzle is supported from the hot zone wall by any appropriate means. A vacuum heat treating furnace and a hot zone therefor incorporating the cooling gas injection nozzle are also described.

Abstract: A convection heating system for vacuum furnaces is described. The convection heating system including a hot zone enclosure defining a hot zone, a plurality of gas injection nozzles for injecting a cooling gas into the heat treatment zone of furnace, an exit port for permitting discharge of the cooling gas from the hot zone, and means for circulating a process gas within the hot zone to provide convective heating and cooling. Each gas injection nozzle has a flap disposed pivotally supported therein for substantially preventing the escape of heat from the hot zone during a heating cycle, but for permitting the injection of the cooling gas into the furnace hot zone during a cooling cycle.

Abstract: A heating element for a vacuum heat treating furnace, a hot zone for a vacuum heat treating furnace, and a vacuum furnace are disclosed. The heating element includes a first heating element portion formed of a thin form of conductive, refractory metal or alloy, and an expansion loop formed in or attached to the first heating element portion, to absorb expansive and contractive forces on the element due to thermal cycling. The heating elements are disposed around the interior surface of the hot zone, which includes a sidewall formed of thermally insulating material. The vacuum heat treating furnace includes a pressure vessel and a hot zone disposed within the pressure vessel.

Abstract: A support or hanger for an electric heating element in a heat treating furnace is disclosed. The heating element support includes a support arm having first and second end portions. First and second ceramic sleeves extend transversely through the support arm and a bracket surrounds at least three sides of the support arm. The bracket is dimensioned and positioned to engage with, and thereby support, the electric heating element. First and second pairs of ceramic spacers are disposed annularly on said first and second ceramic sleeves, respectively. The ceramic spacers are positioned between the bracket and the support arm to prevent contact between the support arm and the bracket. A pin is disposed within each of the first and second ceramic sleeves and extends through the bracket to support and retain the ceramic sleeves, the ceramic spacers, and the bracket on the support arm. In this arrangement, the heating element bears on the metallic bracket and does not cause wear or damage to the ceramic elements.

Abstract: A cooling system for a processing furnace provides improved cooling efficiency in a more compact arrangement than known furnace cooling systems. In the system a blower is situated within the cooling gas plenum but has its intake exterior thereto. The plenum wall and the furnace outer wall define a recirculation channel which is relatively large and free of obstructions. Heat exchanger coils are disposed within the recirculation channel adjacent the blower intake thereby providing a less restricted flow path for the cooling gas.

Abstract: The electric resistance heating elements of a heat treating furnace are suspended within a work chamber by hanger rods threaded into nuts which are welded to the inside of the outer wall of the chamber to avoid the need for forming holes through the outer wall. Spacers are supported by adjacent hanger rods and hold thin radiation shields in spaced relation over the entire span extending from rod-to-rod.

Abstract: A heat treating furnace in which an electrical resistance heating element is disposed in a chamber and is energized by way of a power feed through conductor which extends slidably through the wall of the furnace. An insulating washer and a retaining washer may be installed on and removed from the inner end portion of the feed through conductor from inside the furnace without either removing the conductor from the furnace wall or disconnecting the conductor from the heating element. A power terminal block and inlet and outlet lines for cooling water are adapted to be quickly and easily disconnected from the outer end portion of the feed through conductor to permit the conductor to be easily pulled inwardly through the furnace wall for servicing.

Abstract: A nozzle for delivering cooling gas into the work chamber of a heat treating furnace. The nozzle is formed by a resiliently yieldable metal tube having an overlapping seam and adapted to be contracted radially for insertion through a hole in the wall of the work chamber. After being inserted through the hole, the tube springs outwardly into frictional engagement with the edge of the hole to retain itself in place. Flares on the ends of the tube prevent the tube from shifting endwise relative to the chamber wall.

Abstract: A heat treating furnace having a work chamber of circular cross-section and having banks of electric resistance heating elements formed by rigid and elongated graphite bars. The graphite bars of each bank are interconnected so as to form an octagon located closely adjacent the circular wall of the work chamber and closely approximating the circular shape of the chamber. As a result of the octagonal arrangement, ring-like banks of rigid graphite elements may be space longitudinally along the circular work chamber to enable front-to-rear temperature trim zones to be established in the chamber.