JIS-Z-8753-1989-R2005-ENG.pdf
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1、. : J I S Z*8753 89 4933b08 0079785 8 = ,/-c-7 I UDC 531.788.6 JIS JAPAN ESE INDUSTRIAL STAN DAR D. Measuring Methods of Low Pressures by Thermal Conductivity Gauge JIS Z 8 7 5 3 - 1 9 8 9 Translated and Published bY Japanese Standards Association Printed in Japan Copyright Japanese Standards Associ
2、ation Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/11/2007 00:22:25 MSTNo reproduction or networking permitted without license from IHS -,-,- 1 J I S Z*8753 89 4933b08 0079786 T I In the event of any doubt arising, the original Standar
3、d in Japanese is to be final authority, i - l Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/11/2007 00:22:25 MSTNo reproduction or networking permitted without license from IHS -,-,- _ _ _ J I S
4、Z*8753 89 4i33608 0079787 L UDC 531.788.6 JAPANESE INDUSTRIAL STANDARD J I S Measuring Methods of Low Pressures by Thermal Conductivity Gauge 2 8753-1989 1. Scope using vacuum gauge utilizing the thermal conduction through gas molecules, hereinafter referred to as the “gauges“. This Japanese Industr
5、ial Standard specifies the general methods for measurement of low pressures Remark The method using gauges utilizing the heat transfer by convection is not covered by this Standard. 2. Definition The meanings of the main terms used in this Standard shall be as specified below except those specified
6、in JIS 2 86, JIS Z 8127, and JIS Z 8128. (1) pressure-sensitive element by electric current, or the like. (2) envelope element. (3) vacuum system (4) controlled measuring unit An element contained in the gauge head, such as a filament heated A part of the gauge head, consisting of a receptacle conta
7、ining a pressure-sensitive A vacuum device to be the object of measurement of pressure. A measuring instrument having both a power source which operates the gauge head and the function of measuring resistance and the like and indicating the pressure. 3. Principle of Measurement through the surroundi
8、ng gas molecules from the pressure-sensitive element heated by the electric current depends on the pressure. Pressures are measured electrically by utilizing the fact that the heat loss produced by heat conduction Reference: The heat loss from the pressure-sensitive element depends not only on the p
9、ressure of the surrounding gas but also on the kind of gas, temperature difference between the pressure- sensitive element and the envelope and pressure-sensitive element supporter, the coeffi- cient (accommodation factor) relating to the thermal energy exchange between the surface of the pressure-s
10、ensitive element and the inner surface of the envelope and those modecules colliding with such surfaces, and the emissivity of the surface of the pressure- sensitive element. L e Applicable Standards: JIS Z 8126-Vacuum Technology - Vocabulary (General Terms) JIS 2 8127-Vacuum Technology - Vocabulary
11、 (Vacuum Pumps and Related Terms) JIS Z 8128-Vacuum Technology - Vocabulary (Vacuum Gauges and Related Terms) JIS 2 8750-Methods of Calibration for Vacuum Gauges Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not fo
12、r Resale, 03/11/2007 00:22:25 MSTNo reproduction or networking permitted without license from IHS -,-,- J I S Z*8753 89 m 4933b08 0079788 3 m I I Pirani vacuum gauge .2 Z 8753-1989 Constant voltage type Constant temperature type 10 to lo- io3 to io-1 4. Gauges include the Pirani vacuum gauge, thermo
13、couple gauge, and the like, and they are each constituted of a gauge head and a controlled measuring unit. Following Table shows the kinds of gauges and their main ranges of measuring pressures. Classification and Constitution of Gauges 4.1 Kinds of Gauges and Their Ranges of Measuring Pressure Tabl
14、e. Kinds of Vacuum Gauges and Their Ranges of Measured Pressures Thermocouple gauge Kind of gauge I Range of measuring pressures lo2 to 1 0 - l 4,2 Pirani Vacuum Gauge The constitution of the Pirani vacuum gauge and its principle of measure- ment shall be as follows: (1) Constitution of Gauge Head T
15、he gauge head consists of a filament of a metal having a large resistance-temperature coefficient such as tungsten, platinum, and nickel and a glass or metal envelope. ture about 50 to 300 K higher than that of the envelope, and the heat loss from the filament caused by the gas is detected by the ch
16、ange in resistance value. For this purpose, the gauge head is normally used as one side of the bridge circuit to constitute the gauge, as shown in Fig. 1. (2) Principle of Measurement The filament is heated by an electric current and kept at a tempera- Fig. 1. Example of Constitution of Pirai Vacuum
17、 Gauge F P: Gaugehead T Envelope F Filament D: Temperature compensation Ri, R2: Resistance VR: Variable resistance A Ammeter resistance or compensating tube V Voltmeter M High-sensi tivi ty voltmeter (a) Constant Voltage Type This type measures pressure by detecting, from the unbalanced voltage of t
18、he bridge circuit, the heat loss from the filament depending on the change in pressure when the voltage applied to the bridge circuit is kept constant. but by measuring the heat loss from the filament produced by the gas from the electric power required for the bridge circuit to constantly maintain
19、an equilibrium. In this case, the tempera- ture of the filament does not change because its resistance is maintained constant. Reference: (b) Constant Temperature Type This type measures pressure, not by the change in pressure, In order to compensate for the changes in atmospheric temperature, in so
20、me cases, a compensating tube (dummy tube) having the same form as the gauge head and sealed to keep a constant pressure is incorporated in the case of the constant voltage type, and a temperature compensating resistance is incor- porated in the case of the constant temperature type, at the position
21、 D in Fig. 1. Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/11/2007 00:22:25 MSTNo reproduction or networking permitted without license from IHS -,-,- J I S Z*753 9 49336080079789 5 3 Z 8753- 198
22、9 4.3 Thermocouple Gauge The constitution of the thermocouple gauge and its principle of measure- ment shall be as follows: (1) Constitution of Measuring Probe The gauge head consists of a metal filament made of tungsten, platinum, nickel, or the like, a thermocouple spot welded and having a smaii h
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