Abstract: An immersion heater having a screw plug formed from header and sleeve parts. The header part comprises a stamped, thin sheet of metal having a plurality of holes for the heating elements to extend through and a portion of hexagonal configuration to be gripped by a tool. The sleeve part is a threaded piece of pipe to be screwed into the wall of a fluid-containing vessel. The header and sleeve parts are welded together to form the assembled screw plug.

Abstract: A temperature controlled soldering iron includes an elongated heater assembly with a hollow soldering tip at one end, containing a heating element and a temperature sensing element, which is responsive to the temperature of the tip. The heater assembly includes an outer conductive sheath concentrically disposed around an inner conductive sheath, both of which are attached to a steel bushing. A constantan rod is disposed within the inner sheath and connected to the bushing to form a thermocouple junction therewith. The heating element is connected at one end to the bushing and at the other end to a tubular conductor disposed around and insulated from the constantan wire. A temperature controller surveys the temperature sensed at the thermocouple junction by connection to the constantan wire and the outer sheath. The voltage applied between the tubular conductor and the inner sheath is automatically varied to control the temperature of the heater assembly.

Abstract: A control system to control a glow discharge apparatus, as for ion nitriding, utilizing operator selected parameters. Normally, the control system in an automatic state sequences through a glow discharge process by progressively changing modes. The sequence includes an idle mode, a pumpdown mode, a warming mode, a processing mode, a cooldown mode, and a cycle complete mode. The sequence can be interrupted by the control system to provide a plurality of special states, other than the automatic state, including a manual state, a hold state, a manual reentrant state, a power supply shutdown state, or a furnace shutdown state. While in the processing mode the control system regulates the pressure of an ionized gas in a chamber and the temperature of a workpiece within the chamber.

Abstract: A method of making a glow plug includes the steps of swaging a sheath of a heater having an internal heating coil therein and a compressible washer at the open end of the sheath to reduce the sheath's diameter and to force some of the washer out of the sheath to leave a washer portion of a diameter larger than the swaged sheath diameter. The heater is force fitted into a housing with the external washer being press fitted against an internal bore wall of the housing to form an air-tight seal with the bore wall. This eliminates the usual brazing step of brazing the sheath to the housing to seal against flow of combustion gases therebetween.

Abstract: A glow plug has an outer metal housing have a wall defining an internal axially extending bore and a tubular heater that has an external tubular sheath of metal with a heated end of the sheath extending outwardly of the housing and an opposite internal end within the housing bore. The sheath is structurally secured to and electrically connected to the metal housing and the sheath has a closed outer end. An electrical heating element is positioned within the heater sheath and is electrically connected to the tubular sheath. The heating element has a conductor extending outwardly from the other end of the sheath. Electrical insulating material fills the space between the heating element and the sheath. An insulative compressible washer member is compressed between the sheath and the conductor to provide a first interference fit seal to prevent the flow of gas between the sheath and conductor and into the interior of the tubular heater.

Abstract: A control system and method automatically control a glow discharge apparatus, as for ion nitriding, utilizing operator selected parameters (such as warm-up time, processing time, workpiece operating temperature and chamber pressure). During warm-up the control system provides a profile of the desired workpiece temperature, the desired profile temperature increasing with time at a rate that is reduced as the workpiece approaches its operating temperature. The control system compares the desired profile temperature with the measured workpiece temperature and compares the rate of change of the desired profile temperature with the rate of change of the measured workpiece temperature. It adjusts the level of electrical energy being supplied to the glow discharge in accordance with the comparison results. When the operator selected operating temperature is reached, the control system terminates the profile and operates to maintain that temperature.

Abstract: A furnace wall lining is formed of ceramic fiber modules or batts arranged in stacks or layers between more rigid layers of insulating material to which are connected hangers for supporting electrical resistance heating elements. The more rigid insulating layers are preferably a dense fiber board insulating material having openings into which may be hooked one end of an elongated hanger which lies in a groove across the top face of the rigid insulating layer. An end of the hanger projects inwardly into the furnace chamber from the inner face of the furnace lining and supports the heating element. The rigid layers may be used to compress a stack of soft wall batts therebetween.

Abstract: A control system and method for an apparatus to glow discharge treat (such as ion nitride) a workpiece. The apparatus includes a housing to receive a workpiece and a low pressure atmosphere of ionizable gas (nitrogen and hydrogen for nitriding), and connectors for establishing a glow discharge in the gas with the workpiece connected as the cathode. The control system and method automatically control the apparatus throughout the process, utilizing operator selected parameters (such as warm-up time, processing time, workpiece operating temperature and chamber pressure). The control system divides the selected operating temperature by the selected warm-up time to provide a straight line increase per unit time of the workpiece temperature. Initially the control system accumulates the increases at a rate higher than the straight line increase and then, as the workpiece approaches the selected operating temperature, the control system accumulates the increases at a rate less than the straight line increase.

Abstract: A free-standing, electric heater assembly for an electric furnace includes a heating element support structure of refractory material in the shape of an I-beam. Ceramic rods are inserted through holes in the I-beam web and cemented in place to support the electric heating element. One of the I-beam flanges serves as a base for the assembly while the second flange serves to protect the heating element from damage from falling materials in the furnace.