Chapter 5 Sheathed Ceramic Insulated Thermocouples Book in PDF, ePub and Kindle version is available to download in english. Read online anytime anywhere directly from your device. Click on the download button below to get a free pdf file of Chapter 5 Sheathed Ceramic Insulated Thermocouples book. This book definitely worth reading, it is an incredibly well-written.
When data were being gathered in 1961 for National Bureau of Standards Monograph 40 [3] on Thermocouple Materials, a section was included to cover ceramic packed thermocouple stock "because of the wide use and increasing popularity." New uses continue to be found for this unique heterogeneous materials combination. Compacted ceramic insulated thermocouple material consists of three parts as shown in Fig. 21.
A complete thermocouple temperature sensing assembly, in accordance with the present state of the art, consists of one or more of the following: A. Sensing Element Assembly B. Protecting Tube C. Thermowell D. Terminations E. Miscellaneous Hardware.
Author : American Society for Testing and Materials Publisher : ASTM International Page : 264 pages File Size : 44,52 MB Release : 1981 Category : Thermocouples ISBN :
When data were being gathered in 1961 for National Bureau of Standards Monograph 40 [3] on Thermocouple Materials, a section was included to cover ceramic packed thermocouple stock "because of the wide use and increasing popularity." New uses continue to be found for this unique hetrogeneous materials combination. Compacted ceramic insulated thermocouple material consists of three parts as shown in Fig. 21. The advantages of this configuration are: 1. It isolates the thermocouple wires from environments that may cause rapid deterioration. 2. It reduces long term calibration drift. 3. It lessens temperature versus wire size problems. 4. It provides an excellent high temperature insulation for thermocouple wires. 5. The sheath can be made of a metal compatible with the process in which it is being used and bears the brunt of the environmental effects. 6. It is easy to use: a. Forms easily and retains the bent configuration. b. The sheath can be welded without loss of insulation. c. Available in a wide variety of sizes and materials. d. Readily fabricated into finished thermocouple assemblies with minimum of technique and equipment. e. Useful at high pressures or high temperatures or both. 7. It is inexpensive as a finished thermocouple.
A complete thermocouple temperature sensing assembly, in accordance with the present state of the art, consists of one or more of the following: A. Sensing Element Assembly--In its most basic form this assembly includes two dissimilar wires, supported or separated or both by electrical insulation and joined at one end to form a measuring junction. Such assemblies usually fall into one of three categories; (1) those formed from wires having nonceramic insulation, (2) those with hard-fired ceramic insulators, and (3) those made from sheathed, compacted ceramic-insulated wires. This chapter will deal only with the first two. See Chapter 5 for complete details on the latter.
A complete thermocouple temperature sensing assembly, in accordance with the present state of the art, consists of the following: A. Sensing element assembly including, in its most basic form, two dissimilar wires, supported by an electrical insulator and joined at one end to form a measuring junction. Such assemblies usually fall into one of three categories; those formed from wires have nonceramic insulation, those with hard-fired ceramic insulators, and those made from sheathed, compacted ceramic-insulated wires.
A complete thermocouple temperature sensing assembly, in accordance with the present state of the art, consists of the following; A. Sensing element assembly including, in its most basic form, two dissimilar wires, supported by an electrical insulator and joined at one end to form a measuring junction. Such assemblies usually fall into one of three categories; those formed from wires have nonceramic insulation, those with hard-fired ceramic insulators, and those made from sheathed, compacted ceramic-insulated wires. B. Protection tube--ceramic and metal protection tubes, sometimes referred to as thermowells, serve the purpose of protecting the sensing element assembly from the deleterious effects of corrosive or oxidizing or reducing atmospheres. In some cases, two concentrically arranged protection tubes may be used. The one closest to the sensing element assembly is designated the primary protection tube, while the outer tube is termed the secondary protection tube. Combinations such as an aluminum oxide primary tube and silicon carbide secondary tube often are used to obtain the beneficial characteristics of the combination, such as resistance to cutting flame action, and ability to resist thermal shock. C. Connector--sensing element assembly wire terminations are made to either (a) Terminals (b) Connection head 1. General purpose type 2. Screw cover type 3. Open type (c) Plug and jack quick-disconnect (d) Military standard (MS) type of connector D. Miscellaneous hardware such as (a) Pipe nipple or adapter to join the protection tube to the head (b) Thermocouple gland--used primarily with sheathed, compacted ceramic-insulated thermocouple assemblies to serve the dual function of mounting and sealing-off pressure in the mounting hole (see Section 5).