US 4,688,039 A · Heat-insulated telemetry system for vacuum furnace

Abstract

A heat-insulating box houses a telemetry system of high accuracy for use within a high-temperature vacuum furnace. The container includes an inner box formed by a block of rigid heat-insulating material having a cavity which contains a telemetry system chassis and its components, including such items as batteries, transmitters, switches, thermocouple elements including transition tubes, isothermal double-layer terminal strips, and the like. A plurality of very fine thermocouple conductors of dissimilar metal extend from the thermocouple junction tips on work pieces outside of the box through the heat-insulating inner block to the thermocouple transition tubes, and then, by way of the isothermal double-layer terminal strip to the transmitters. An antenna lead is carried through the wall of the box to a transmitting antenna mounted on the front wall of the box. Pressure switches in the cavity within the box control the ON-OFF condition of the transmitters. These pressure switches are normally open and do not close until the pressure falls to a vacuum pressure corresponding to the pressure in the vacuum furnace, and the switches open when the pressure rises to a preselected value. Thus, the transmitters are ON for only a portion of a complete work cycle. Battery energy is conserved and battery life extended. Various features of the construction of the telemetry box and its contents contribute toward insulating the telemetry transmitters from the high heat of the furnace.

Claims16

Dependent claims

A heat-insulating container for housing a telemetry system for use in a high-vacuum furnace, said container comprising:

a. an outer metal box;
b. an inner box comprising a block of heat-insulating material within said outer box, the length and width of said block corresponding to that of said outer box, the height of said block being less than that of said outer box;
c. a primary cavity in said block;
d. a secondary cavity adjacent said primary cavity, said secondary cavity having a floor which slopes downwardly toward a front wall of said outer box;
e. a telemetry chassis and component parts in said primary cavity, said parts including batteries, transmitters, pressure switches, thermocouple elements including transition tubes, an isothermal double-layer terminal strip having input and output sides, and conductive interconnecting means, including means connecting said thermocouple elements to said transmitters and means connecting said transmitters to said batteries through said pressure switches;
f. an insert of heat-insulating material slidably and removably fitted into said secondary cavity, said insert having an inclined bottom having a slope corresponding to that of said slope of said floor of said primary cavity;
g. a removable top plate of heat-insulating material having a depending portion removably fitted into an upper portion of said primary cavity;
and
h. a metal cover for said container;
i. said pressure switches being normally open and adapted to close when pressure within said primary cavity falls to a pre-selected sub-atmospheric pressure, thereby to complete the battery connection to a transmitter.

7 more elements

A heat-insulating container for housing a telemetry chassis intended for use within a high-temperature vacuum furnace for transmitting temperature data to a receiving station external of the furnace, said container including:

a. a block of material having heat-insulated properties having therein a primary cavity and an adjacent secondary cavity;
b. a door insert slidable into and out of said secondary cavity;
c. a cover insulating material for said primary cavity;
d. a telemetry chassis within said primary cavity, said telemetry chassis including transmitters, batteries, thermocouple elements including transition tubes, and interconnecting conductors;
e. said thermocouple elements including pairs of fine diameter dissimilar metal conductors extending from said thermocouple transition tubes within said primary cavity through said block to thermocouple junction tips of dissimilar metals outside of said block and outside of said container;
f. said thermocouple elements also including pairs of dissimilar metal conductors of larger diameter than that of said fine conductors, said larger diameter conductors being located within said primary cavity and extending from said transition tubes to said transmitters;
g. said interconnecting conductors including means connecting said batteries to said transmitters.

4 more elements

Dependencies are inferred from the claim text.

Heat-insulated telemetry system for vacuum furnace

Life of this patent

Heat-insulated telemetry system for vacuum furnace

Life of this patent

Abstract

Claims16