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JJG 993-2018

Search Result of Chinese Standard: 'JJG 993-2018'
Standard IDContents [version]USDSTEP2[PDF] delivered inStandard Title (Description)StatusRelated Standard
JJG 993-2018English299 Add to Cart Days<=4 Electric Ventilation Psychrometers Valid JJG 993-2018
JJG 993-2018Chinese17 Add to Cart <=1-day [PDF from Chinese Authority, or Standard Committee, or Publishing House]  

   
Detail Information of JJG 993-2018; JJG993-2018
Description (Translated English): Electric Ventilation Psychrometers
Sector / Industry: Metrology & Measurement Industry Standard
Word Count Estimation: 17,159
Date of Issue: 2018-06-25
Date of Implementation: 2018-12-25
Older Standard (superseded by this standard): JJG 993-2004
Drafting Organization: China Institute of Metrology
Administrative Organization: National Physical and Chemical Metrology Technical Committee
Regulation (derived from): State Administration of Markets, Announcement No. 13 of 2018
Issuing agency(ies): State market supervision and administration


JJG 993-2018
Electric Ventilation Psychrometers
National Metrology Verification Regulations of the People's Republic
Electric ventilation dry and wet table
Published on.2018-06-25
2018-12-25 implementation
State Administration of Markets issued
Electric ventilation dry and wet meter verification procedures
VerificationRegulationofElectric
VentilationPsychrometers
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Replace JJG 993-2004
Focal Point. National Physical and Chemical Metrology Technical Committee
Main drafting unit. China Institute of Metrology
Participated in drafting unit. Jinan Changfeng Guozheng Technology Development Co., Ltd.
This procedure entrusts the National Physical and Chemical Metrology Technical Committee to explain
The main drafters of this procedure.
Ren Changqing China Institute of Metrology
Participate in the drafters.
Yi Hong China Institute of Metrology
Yang Ju China Institute of Metrology
Zhang Wei Jinan Changfeng Guozheng Technology Development Co., Ltd.
table of Contents
Introduction (II)
1 range (1)
2 Overview (1)
3 Metrological performance requirements (1)
3.1 indication error (1)
4 General technical requirements (1)
4.1 Ordinary wet and dry watch (1)
4.2 Digital Dry and Wet Table (2)
5 measuring instrument control (2)
5.1 Verification conditions (2)
5.2 Verification project (4)
5.3 Verification method (4)
5.4 Processing of verification results (6)
5.5 Verification cycle (6)
Appendix A Calculation of A value of wet and dry table (7)
Appendix B Electric ventilation dry and wet table temperature indication error verification record format (8)
Appendix C Electric ventilation dry and wet table humidity indication error verification record format (9)
Appendix D Verification certificate/verification result notice page format (10)
introduction
JJF1002 "Rules for the preparation of national metrological verification procedures", JJF1001 "General measurement terms and definitions"
A basic series of specifications that support the revision of the procedures.
Compared with JJG 993-2004, in addition to editorial changes, the main technical changes of this specification are as follows.
--- Temperature range. modified to (5~50) °C, humidity range. (10~95)% RH. (see range 1);
---Working standard standard wet bulb thermometer does not specify the absolute value of the error and the difference between the dry and wet thermometer indication errors
Value (see Table 1);
--- Remove first-class and second-class mercury thermometers; standard digital thermometers at work level (see Table 2); humidity
The standard increases the maximum allowable error column (see Table 3);
--- Increase the temperature and humidity standard box for the main supporting equipment (see Table 4);
--- Temperature and humidity equipment are listed in Table 4, and the indicators are more detailed;
--- Humidity check points have been increased or decreased (see Table 6).
The previous versions of this procedure are released as follows.
---JJG 993-2004.
Electric ventilation dry and wet meter verification procedures
1 Scope
This procedure applies to the temperature measurement range (5~50) °C, humidity measurement range (10~95)% RH electric pass
The first test, follow-up test and in-use check of the air-drying wet watch.
2 Overview
Electric ventilation wet and dry watch (hereinafter collectively referred to as wet and dry watch) includes two types of digital wet and dry watch and ordinary dry and wet watch.
The wet and dry watch consists of two thermometers, a ventilator, a water cup and a radiation protection tube. The digital wet and dry watch also includes
Temperature and humidity display. Its principle block diagram is shown in Figure 1.
Wet and dry watch
Dry bulb thermometer
Wet bulb thermometer →
temperature
measuring
Humidity value
Calculate or display
Figure 1 dry and wet table block diagram
The wet and dry watch works on the principle that at a constant ventilation speed, air flows through the surface of the dry and wet bulb thermometer due to
The wet bulb thermometer has a wet gauze, and the surface moisture vaporizes to lower the wet bulb temperature, and the lowered temperature value is the wet bulb temperature.
degree. After the dry and wet bulb temperature is measured by the dry and wet bulb thermometer, the relative humidity value is calculated according to the dry and wet table equation.
3 Metrological performance requirements
3.1 indication error
The dry and wet indication values are shown in Table 1.
Table 1 Dry and wet indication value error
Dry and wet table level 2 standard working level
Dry bulb thermometer indication error/°C ±0.08 ±0.3
Wet ball thermometer indication error/°C ±0.08 -
Dry and wet thermometer indication error
The absolute value of the difference/° C
≤0.1 -
Relative humidity /%RH ≤2.0 ≤5.0
Note. 1. The wet bulb thermometer indicates the temperature indication when the wet ball gauze sleeve is not installed.
2. Ordinary wet and dry watch can not be used as a humidity secondary standard.
4 General technical requirements
4.1 Ordinary wet and dry watch
4.1.1 The shape of the sensor should be intact and its outer surface should be polished or blackened.
4.1.2 The dry and wet bulb thermometer of the sensor shall be concentric with its radiation protection tube (layer).
Related standard:   JJG 1148-2018  JJG 1149-2018
   
 
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