钟罩式气体流量标准装置自动检定系统的研究

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摘要

钟罩式气体流量标准装置是气体流量计量的传递标准和对气体流量计进行检

定、测试的标准装置，在国内外已大量使用。

论文主要包括钟罩装置的原理和结构分析，钟罩标准容积的不确定度评定及

钟罩装置自动检定系统的设计，其中自动检定系统设计是本文的主要工作。

通过国内外钟罩装置结构和技术上的比较，分析了钟罩装置的发展趋势，提

出了改进的方向和方法。依据国家标准检定规程，对尺寸法测量钟罩装置标准容

积的测量不确定度进行了评定，讨论了国标未涉及的高精度钟罩装置的不确定度

来源。

根据各种气体流量计检定功能要求，设计了下位机和上位机两级系统实现自

动化检定。下位机硬件电路以新型单片机为核心，执行控制钟罩升降，实时数据

采集，精确计时等任务。在检定过程中，下位机定时将采集到的数据送至上位机，

经上位机处理后刷新显示状态参数；在检定结束时，将最后的检定数据送到上位

机。上位机采用 Delphi 语言设计程序，接收来自下位机的实时检定数据，并按相

应的流量计检定规程要求进行处理，可在检定结束时直接得到检定结果，并将结

果存入由 SQL Server 数据库管理软件设计的数据库中，便于检定数据维护查询使

用。

该自动检定系统保留了检定参数的历史数据，有效确保计量仪器的可溯源性，

并提高了检定效率。实现了四种自动检定方式，具有较好的实用性和通用性。

关键词：钟罩式气体流量标准装置自动检定不确定度评定单片机

ABSTRACT

The bell prover is a transfer standard of flow measurement and a standard facility

to calibrate flow meters. It is widely used at home and abroad.

This paper contains 3 aspects as follows: analyzing the bell prover’s principle

and configuration, evaluating the uncertainty of its standard cubage, and designing an

automatic calibration system of bell prover gas calibration facility. The design is the

most important work.

By comparing the bell provers at home and abroad, this paper analyzes the

development trend, and puts forward the direction and the method for improvement.

According to the national standard for calibration, this paper evaluates the uncertainty

of a bell prover’s standard cubage, and discusses the uncertainty sources of the cubage

whose precision is excelled 0.2%.

According to the demanded functions of calibration, an automatic calibration

system is worked out which is composed of lower and upper. A new type of MCU is

chosen as the core of hardware. It is used for controlling the movement of the bell,

collecting real time data, timing the calibration time and executing some other tasks.

During the calibration, the lower sends acquired data to the upper periodically, and

then the data is processed and refreshed in the screen.

The upper is designed by Delphi. It receives the real time data and processes

them according to the correlative regulations till achieve the result. The result is

stored into database, which is designed by software of SQL Server, for that it could be

maintained or queried easily.

The automatic calibration system could store all the parameters’ historical data in

calibration, so the traceability of the facility can be insured, and the efficiency is

advanced. It realizes 4 calibrating methods, and has the characteristics of practicality

and generality.

Key words：Bell Prover，Automatic Calibration，Evaluation of

Uncertainty，MCU

中文摘要

ABSTRACT

第一章绪论···························································································································· 1

§1.1 课题背景 ················································································································ 1

§1.1.1 流量计量概述 ··························································································· 1

§1.1.2 气体流量计检定装置 ·····································································2

§1.1.3 钟罩式标准装置的应用 ·································································3

§1.2 国内外钟罩装置现状和发展趋势·····························································3

§1.2.1 国外钟罩标准装置的现状······························································3

§1.2.2 我国钟罩式气体流量标准装置现状··············································5

§1.2.3 钟罩式气体流量标准装置的发展趋势··········································6

§1.3 本文主要研究内容 ····················································································7

第二章钟罩式气体流量标准装置···················································································· 9

§2.1 气体流量标准装置分类······················································································ 9

§2.2 钟罩式气体流量标准装置的原理···································································· 9

§2.2.1 钟罩式气体流量标准装置基本原理 ··················································· 9

§2.2.2 流量计算公式 ························································································· 11

§2.3 钟罩式标准装置的结构···················································································· 13

§2.3.1 对气体流量装置的一般要求······························································· 13

§2.3.2 钟罩式标准装置的结构特点······························································· 14

§2.3.3 德国PTB研制的钟罩装置 ····································································· 18

§2.4 钟罩装置标准容积的不确定度评定······························································ 19

§2.4.1 钟罩标准容积的不确定度评定 ·························································· 19

§2.4.2 高精度钟罩装置测量不确定度的讨论············································· 23

第三章钟罩式标准装置自动检定系统设计································································ 26

§3.1 自动检定系统分析····························································································· 26

§3.1.1 系统要求 ·································································································· 26

§3.1.2 系统主要功能 ························································································· 26

§3.1.3 工作方式 ·································································································· 27

§3.1.4 试验中使用的钟罩式装置 ··································································· 27

§3.2 检定数据处理方法····························································································· 28

§3.2.1 钟罩定容方式 ························································································· 28

§3.2.2 手动方式和流量计定容方式······························································· 30

§3.2.3 模拟量方式······························································································ 32

§3.3 系统总体设计······································································································ 33

§3.4 下位机设计·········································································································· 34

§3.4.1 下位机主要功能····················································································· 34

§3.4.2 单片机的选择 ························································································· 35

§3.4.3 时钟、计数与计时 ················································································ 38

§3.4.4 配置交叉开关 ························································································· 40

§3.4.5 信号采集 ·································································································· 42

§3.4.6 通讯 ··········································································································· 45

§3.4.7 检定流程 ·································································································· 45

§3.4.8 下位机软件设计····················································································· 47

§3.4.9 内部数据地址分配 ················································································ 49

§3.4.10 还需注意的问题··················································································· 50

§3.5 系统上位机设计 ································································································· 51

§3.5.1 上位机主要任务····················································································· 51

§3.5.2 数据库系统设计····················································································· 52

§3.5.3 用户界面及操作····················································································· 56

第四章总结和展望 ············································································································ 61

参考文献 ·································································································································· 63

第一章绪论

流量计量是能源计量中的一个重要参数，与国民经济发展和人民生活有着千

丝万缕的联系。从居民家庭里用于计量收费的燃气表、水表和供热使用的热量表，

到国内进出口的原油、天然气贸易结算等无不与流量计量有关。随着“西气东输”

工程的迅速推进，将把我国西北部的天然气资源不断的通过地下管道输送到东部

的广阔市场。由于天然气的特性，长距离的管道输送和存贮需要使用大量的气体

流量计进行计量。因此，这些流量计检定和校准的准确性是流量量值传递或溯源

中最重要的环节，不仅关系到贸易双方的经济利益，而且对我国国民经济的发展

有很重要的社会效益[1,2]。

气体流量计量是石油、石化、冶金、电力、医药等工业生产过程的重要参数。

在流程工业中，检测和控制的温度、压力、流量、物位和成分分析诸参数的仪表

中，流量仪表约占总台数的 20%，费用约为 35%左右[3]。对一部分工业生产来说，

气体流量的监测和控制水平直接关系到生产质量、生产效率和能源的利用。

家庭生活的需要和工业上的依赖，为流量仪表开辟了广阔的市场空间，投入

市场的气体流量计也逐年增加。为保证产品质量和使用效果，这些流量计在出厂

前必须按照国家有关规定作严格的检定，而且一些高精度的气体流量计在使用一

段时间之后也要进行周期性的检定，这对检定精度和检定效率提出了更高的要求。

钟罩式气体流量标准装置是我国检定气体流量计的主要装置之一，其计量精

度较高、使用和维修都很方便，被气体流量计生产厂家广泛采用，也是研究院、

计量站的重要气体流量标准装置。本文通过对钟罩式装置和其检定方法的研究，

设计一套相关的自动检定系统，以其完备功能服务于社会。

§1.1 课题背景

§1.1.1 流量计量概述

计量是工业生产的眼睛。流量计量是计量科学技术的组成部分之一，它与国

民经济、国防建设、科学研究有密切的关系。做好这一工作，对保证产品质量、

提高生产效率、促进科学技术的发展都具有重要的作用。特别是在能源危机、工

业生产自动化程度愈来愈高的当今，流量计在国民经济中的地位与作用更加明显

[4]。

钟罩式气体流量标准装置自动检定系统的研究

流量测量的流体是多样化的，如测量对象有气体、液体、混合流体；流体的

温度、压力、流量有较大的差异；对测量准确度的要求也各不相同。因此，流量

测量的任务就是根据测量目的，被测流体的种类、流动状态、测量场所等测量条

件，研究各种相应的测量方法和检定系统，建立流量计量的基、标准装置，以保

证量值传递和流量测量的准确度。

流量测量的目的主要有两类：其一为流体物资贸易核算储运管理和污水废气

排放控制的总量计量；其二为流程工业提高产品质量和生产效率，降低成本以及

水利工程和环境保护等作必要的流量检测和控制[3]。

贸易核算是流量计量应用最广的一面。贸易核算不仅存在于国家之间、企业

之间的大宗交易中，和人民的日常生活也密不可分。我国城市居民，几乎每家每

户有装有燃气表和水表。这些流量仪表关系到每个家庭的日常开支，每一次燃气

价格或自来水价格的变动都会引起广泛地关注……随着我国“西气东输”工程的进

展，燃气普及地区和用量逐年增加，相应的燃气表也必须以更高的质量服务于亿

万个家庭。

工业生产过程的控制是流量计量求“精”的一面。在化工行业，流量计量不准确

会造成化学成分配比失调，无法保证产品质量，严重的还会发生生产安全事故。

在电力工业生产中，对液体、气体、蒸汽等介质流量的测量和调节占有重要地位，

而且随着高温高压大容量机组的发展，流量测量已成为保证发电厂安全运行的重

要环节。在钢铁工业生产中，炼钢过程中循环水和氧气（或空气）的流量测量是

保证产品质量的重要参数之一。随着空间技术的发展，对流量计量提出了相当高

的要求。如宇宙飞船、核潜艇的核动力控制，离不开流量仪表；火箭发功机试车

一次消耗大量的液化燃料，流量测量不准会造成巨大经济损失。

可以看出，流量计量广泛应用于工农业生产、国防建设、科学研究、对外贸

易以及人民生活各个领域之中，因此，流量计量的相关产品也具有很大的市场前

景和应用价值。

§1.1.2 气体流量计检定装置

我国的城市化、现代化进程，为流量计提供了广阔的发展前景，而数量增加

的同时更要重视质量。流量计在出厂或使用之前，必须对其计量性能进行测试或

检定，以保证产品质量和使用的准确度。为此，就必须建立复现流量单位量值的

标准装置，即能够提供确定准确度流量值的测量设备。

气体流量计的检定装置分为原始标准（也称原级标准）和传递标准（也称次

第一章绪论

级标准）[1,5,6,7]。原始标准是气体流量的最高标准，是依据流量的基本定义予以实

施的，即通过标准量器或衡器等作为容积V或质量m的度量设备，从而得到体积流

量或质量流量。原始气体标准装置包括钟罩式气体流量标准装置，PVTt法气体流

量标准装置和Mt法气体流量标准装置。

次级标准装置是通过原始标准装置进行量值传递的。应用最多的是标准表法

气体流量标准装置，其基本原理是基于流体力学的连续性方程。以标准流量计为

标准器，使流体连续通过标准流量计和被检流量计，比较两者的瞬时流量值，或

比较一段时间内的累积流量值，从而确定被检流量计的计量性能。

原始流量装置是流量装置中计量性能最高的，标准表法流量装置及部分流量

计的量值要由原始标准装置确定。

§1.1.3 钟罩式标准装置的应用

钟罩式气体流量标准装置是一种重要的流量计检定标准装置，主要用于气体

容积式流量计和速度式流量计的检定，如：气体转子流量计，煤气表，涡轮流量

计，涡街流量计等。其检定精度较高、使用范围广、结构简单、使用和维修都很

方便，已被许多气体流量计生产企业及计量检定部门用作仪表出厂前的检定设备。

而且，钟罩式装置属于原始标准，对基、标准的建立和标准的传递起到至关重要

的作用，在国家或地区之间的标准比对方面也占有一席之地。

随着工艺水平和自动化技术的提高，钟罩式装置的检定精度越来越高，使用

起来也越来越方便。世界上主要的计量院和实验室都配有钟罩式装置，承担着地

区的标准传递和检定任务。

我国钟罩式装置的使用也很普遍，而且最近几年开展了一些装置改造的项目，

在提高检定精度或者实现自动化检定方面做出了努力。应该说，钟罩式装置在我

国流量计检定和量值传递方面发挥了很大的作用，在“西气东输”的大背景下得

到更多地重视，在目前技术条件下的应用还有潜力可挖。

§1.2 国内外钟罩装置现状和发展趋势

§1.2.1 国外钟罩标准装置的现状

钟罩式气体流量标准装置被许多国家所采用[8]。在 1997 年~1999 年，12 个欧

洲实验室对其使用的钟罩装置作了一次内部比对，旨在确保国家实验室之间具有

良好的一致性[9] 。这 12 个实验室都是EUROMET（European Collaboration in

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摘要：

摘要钟罩式气体流量标准装置是气体流量计量的传递标准和对气体流量计进行检定、测试的标准装置，在国内外已大量使用。论文主要包括钟罩装置的原理和结构分析，钟罩标准容积的不确定度评定及钟罩装置自动检定系统的设计，其中自动检定系统设计是本文的主要工作。通过国内外钟罩装置结构和技术上的比较，分析了钟罩装置的发展趋势，提出了改进的方向和方法。依据国家标准检定规程，对尺寸法测量钟罩装置标准容积的测量不确定度进行了评定，讨论了国标未涉及的高精度钟罩装置的不确定度来源。根据各种气体流量计检定功能要求，设计了下位机和上位机两级系统实现自动化检定。下位机硬件电路以新型单片机为核心，执行控制钟罩升降，实时数据采集，精确...

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钟罩式气体流量标准装置自动检定系统的研究.pdf

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钟罩式气体流量标准装置自动检定系统的研究

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