Patent Application
20140050248
The present invention generally relates to an input/output connector device, and method related thereto, for terminating a cold junction of a thermocouple device.
A thermocouple is a temperature measuring device that produces a voltage proportional to the temperature difference between two junctions (one hot and one cold) of dissimilar metals. When one junction is either held at a reference (for example, an ice bath) or at a known temperature, the other junction's temperature can be predicted based on the voltage across the circuit and the known temperature of the reference junction. Since holding one of the junctions at a reference temperature outside of the laboratory is not practical, a second temperature measuring device (Resistance Temperature Device, RTD for example) may be used to measure the temperature of the reference junction. RTDs are usually accurate over a narrower temperature range than thermocouples so this junction typically resides within the electronics assembly (inside a full authority digital engine control (FADEC), for example) where the temperature range is more controlled.
Referring to
One disadvantage of known thermocouple devices using cold junctions, is the amount of time required from a skilled technician to hand wire the cold junction to a connector. Further, the cold junction, connector, and wiring between them, may use a significant amount of real estate on a printed wire board used for supporting the cold junction and the connector, and additionally as a back shell or back plate of the cold junction module 10, as shown in
Therefore, a need exists for a thermocouple device, and a method for providing the thermocouple device, which includes a cold junction module with less parts, and reduces labor time related to wiring of the cold junction.
In an aspect of the invention, a thermocouple connection device for terminating a cold junction of a thermocouple device includes a housing defining a hollow interior space therein configured to receive a substrate positioned within the hollow interior space. The substrate includes an isothermal block. A plurality of connection elements are thermally conductive. Each of the connection elements include a first portion coupled to a second portion at a cold junction. The cold junction is positioned within the isothermal block such that the first portion and the second portion extend through opposite ends of the substrate. The first and second portions of the connection elements extend through the housing in opposite directions to each other parallel to a longitudinal axis passing through a center of the hollow interior space of the housing. A first distal end of the first portion is connectable to a control device, and a second distal end of the second portion is connectable to a hot junction. A resistance temperature device (RTD) is coupled to the isothermal block adjacent the cold junctions for measuring a temperature in proximity of the cold junctions, and the RTD is connectable to the control device.
These and other objects, features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. The various features of the drawings are not to scale as the illustrations are for clarity in facilitating one skilled in the art in understanding the invention in conjunction with the detailed description. In the drawings:
Referring to
Referring to
A thermocouple system 200 is shown in
A resistance temperature device (RTD) 150 is coupled to the isothermal block 120 adjacent the cold junctions 142 as shown in
The connection elements 130 may include specified materials for the first portion 134 and the second portion 138. The first portion 134 may be comprised of copper at the first distal end 136, and Chromel™/Copper at the handle portion 135. The second portion 138 may be comprised of Chromel™ and Alumel™ (Chromel™/Alumel™), wherein Chromel™ is an alloy which may include approximately 90 percent nickel and 10 percent chromium, and Alumel™ is an alloy consisting of approximately 95% nickel, 2% manganese, 2% aluminium and 1% silicon.
Referring to
The thermocouple system 200 includes the thermocouple connector 100 for measuring the temperature difference between a junction of dissimilar metals. For example, Type K, Chromel™-Alumel™ may be used and produce a small voltage that is proportional to the temperature difference and measured by the FADEC 250. The cold junction's temperature is better maintained using the isothermal block 120, and is measured using the RTD and the temperature monitor module 258 to measure the thermocouple connector 100 voltage in conjunction with the computer 254 of the FADEC 250, to provide a proportional temperature at the cold junction. The thermocouple connector 100 provides an advantage over the prior art thermocouple modules shown in
While the present invention has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that changes in forms and details may be made without departing from the spirit and scope of the present application. It is therefore intended that the present invention not be limited to the exact forms and details described and illustrated herein, but falls within the scope of the appended claims.
