膜式流量计

1范围本建议适用于采用具有柔形薄壁的测量室测量气体流量的作为容积式流量计的膜式煤气表。包括装有温度转换装置的煤气表。对于上述定义的容积式流量计的膜式煤气表，本建议是对OIML国际建议R6“容积式气体流量计的一般规定”的补充，其中各种规定以及下述要求都是适用的。注：本建议中，膜式煤气表称之为“煤气表”或“仪表”。2流量范围2．1最大流量和相应的最小流量上限的规定值列于表1。2．2煤气表可以具有比表1所列的最小流量还低的数值，但是该较低值应是表中所列数值的诸值中的某个值或是这些值中某个值的十进位约数。3结构细节3…     

LMN系列工业煤气表

LMN系列工业煤气表(LMN—10、16、25、40、65、100、160、250型)适用于工业和服务行业计量煤气、天燃气、液化气等可燃气体的累计耗量,也可用于无腐蚀气体或特定气体的计量。 LMN系列工业煤气表是我国第一代装配式的膜式煤气表。这种产品具有承压能力高,耐腐蚀、性能稳定,维修方便等特点。替代焊接式大流量煤气表。     

基于GPRS的煤气表数据采集系统设计

总结了近些年煤气表采集状况,探究基于GPRS技术的煤气表数据采集系统的设计,力求能找到一种高效、准确的方法来完成煤气表的数据采集任务。首先介绍系统的总体设计方案,然后介绍系统的硬件设计和软件设计,重点介绍系统中各模块的硬件设计。通过实验发现,该系统能将煤气表采集的数据发送至服务器上,完成煤气表数据的采集任务。     

微功耗IC卡煤气表诞生

随着“西气东送”工程的快速开展,天然气必将进入我国的千家万户。煤气表将和电表、水表一样,成为家庭的必需品。传统的机械式煤气表因其功能单一,只能累计煤气流量,且是先用气后付费,给煤气公司的管理造成诸多不便。目前市场上已出现一些IC卡煤气表。使用IC卡作为付费的介质,用户先付费后用气,使管理更加合理。但IC卡煤气表设计中的一个重要问题是功耗。为保证使用安全,IC卡煤气表必须使用电池供电。因此,CPU及外围电路的功耗必须足够低,才能使IC卡煤气表进入实用     

信息与动态

信息与动态新型电子卡式煤气表开发研制成功北京煤气公司与清华大学蓬远科贸公司合作开发研制成功电子卡煤气表，近日通过专家技术鉴定。该表属智能型煤气表，它采用电子集成元件和机械部件，实现机电一体化结构，技术先进、整机紧凑、安全可靠、可移植性强，不影响原型煤...     

简讯

简讯智能家用煤气表问世天津市自动化仪表十厂研制成功智能化家用煤气表并投放市场。该产品具有自动识别、自动计费、自动开启等功能。只要将集成电路卡插入后，可正常供气，当规定期限临近，可自动报警，提醒用户换卡。使用这种煤气表，无需工作人员入户查表。ＤＨ－９１...     

复费率IC卡智能电子煤气表的设计

利用AT89C51单片机，设计了一种能满足现有收费需要，使用安全可靠，计量控制准确的复费率IC卡智能电子煤气表。本文介绍该仪表的硬伯和软件的设计思想。     

辽宁省机械工业科技成果信息报导

31Go71 C_2 LN—100型煤气表该产品是皮膜式流量表,采用焊接式结构,适用于工厂,饭店、食堂等计量城市煤气,天然气的消耗。该产品适应我国市场急需,为用户提供新的计量手段,使用户节约燃气30％～50％。主要参数:额定流量100m     

基于构成模式的煤气表读数字符识别技术研究

对煤气表检定装置中的表值读数字符识别进行了研究,应用图像处理和模式识别技术来完成煤气表读数识别,设计编制了相应软件.针对煤气表读数滚动变化特点而形成的不同区域字符构成模式,采用不同识别策略与算法.对完整型字符采用结构特征判别法识别,对不完整型字符采用模板匹配法进行识别.     

基于IC卡预付费煤气表设计

设计一款基于IC卡预付费煤气表,以实现预充值、气阀控制,以及漏气、余值不足等报警和IC卡检测及相关数据处理等功能。解决了传统煤气表浪费人力资源、影响居民生活、收费管理难等问题。     

Comparison of different approaches to calculate a final meter factor for rotary-type natural gas displacement meters

The meter factor is the ratio between the reference volume and the indicated test meter volume for a particular flow rate. In some applications, a final and a single meter factor that covers all the flow meter rates is required, and there are several approaches to calculate it. However, none of them are specific to rotary-type natural gas displacement meters. In this paper, certain established approaches, such as AGA 7, AGA 9, non-weighted and weighted regression lines were applied to calibration data of this type of meter and their results were compared. An Excel spreadsheet was developed to calculate the final meter factors using all these approaches and to indicate users the one with the lowest uncertainty, based on input data in order to configure the flow computer. In the specific case studies shown, the approaches using linear regression were found to be more suitable.     

温压补偿型超声气体质量流量计

对超声时差法进行算法改进后，结合气体密度公式推导出超声质量流量方程，据此设计出温压补偿型超声气体质量流量计，给出了流量计核心系统及温压补偿部分的硬件设计。将只用于流体体积流量测量的超声流量计推广到气体质量流量测量领域，使超声流量计趋向理想化。经实验证明此流量计在测量常压空气时精度可达1．42％。     

超声波气体流量计的管道模型仿真和误差分析

为满足不断发展的超声波气体流量计测量精度的需要,改进传感器的设计精度和有效降低安装测试及样机调试成本,针对制约超声波气体流量计测量精度主要误差源之一的管道流场分析问题,结合计算机建模数值仿真技术及实验技术对其流场设计参数以及弯管安装条件等对超声波测量误差产生原因进行定量分析.理论研究和仿真实验结果表明,可以量化分析气体超声波流量计流场误差产生的原因、范围,并通过限定流场修止系数更有效地降低其测量误差,这项研究对该超声波气体流量计的优化设计和工程应用具有一定的指导意义.     

Study on application of wet gas metering technology in shale gas measurement

The application of wet gas flow meter at shale gas wellhead is of great significance to reduce the investment and operation cost of shale gas extraction. In this paper, the flow conditions at the wellhead of shale gas and the principles of the current wet gas flow meters are briefly analyzed. A wet gas flow meter was tested on the wet gas flow test facility, and its performance of flow rates evaluation is studied, which is helpful to optimize the wet gas metering process design of shale gas wellhead and to improve the wet gas metering technology. This study shows that the measurement principles of the current wet gas flow meters are feasible, however, the calibration by using the wet natural gas at working conditions can help to enhance the meter's measure performance.     

Multiphase flow measurements using coupled slotted orifice plate and swirl flow meter

Multiphase flow metering is a major focus for oil and gas industries. The performance of a modified version of a close coupled slotted orifice plate and swirl flow meter for multiphase flow was evaluated to provide further development of a new type of multiphase flow meter. The slotted orifice provides well homogenized flow for several pipe diameters downstream of the plate. This characteristic provides a homogeneous mixture at the inlet of the swirl meter for a wide range of gas volume fractions (GVF) and flow rates. In order to evaluate the performance of the designed flow-meter, its response was investigated for varying pressures and water flow rates. The proper correlations were established to provide high accurate two-phase flow measurements. The new proposed approach provides the GVF measurement with less than ±0.63% uncertainty for GVF range from 60% to 95%.     

基于单片机MSP430智能化天然气表的设计

主要介绍基于单片机MSP430的智能化天然气表的设计。该天然气表可以对天然气流量进行计量,同时还可以进行火灾探测、电压监控、漏气检测、通风控制。为了实现预付费功能,方便天然气公司的管理,该设计采用非接触式IC卡作为付费介质。     

High GVF and low pressure gas–liquid two-phase flow measurement based on dual-cone flowmeter

Parameter measurement of gas–liquid two-phase flows with a high gas volume fraction (GVF) has received great attention in the research field of multiphase flow. The cone meter, as a new proposed differential pressure (DP) meter, is increasingly being applied in flowrate measurement of gas–liquid two-phase flow. A dual-parameter measurement method of gas–liquid two-phase flow based on a dual-cone meter is proposed. The two-phase flow is investigated in a horizontal pipeline with high GVF and low pressure, and exists in the form of annular flow. By adding a second cone meter, both gas mass fraction (GMF) and mass flowrate are measured. The pressure drop performances of five different sized cones have been discussed to make a cooperating cone selection and efficiently position the dual-cone in the pipe. Dual-cone flowmeter experiments of 0.45 and 0.65 equivalent diameter ratio combination, and 0.65 and 0.85 equivalent diameter ratio combination are respectively carried out to analyze the linearity of two-phase flow multiplier with Lockhart–Martinelli parameter and obtain the dual-parameter measurement results. The relative experiment error of GMF, gas mass flowrate and total mass flowrate are respectively within ±7%, ±5% and ±10%. The relative error of the liquid phase is within ±10% when the liquid mass fraction is beyond 40%. The experimental results show that it is efficient to utilize this dual-cone method for high GVF and low pressure gas–liquid two-phase flow measurement.     

Wet gas metering with a horizontally mounted Venturi meter

Wet gas metering is becoming an increasingly important problem to the Oil and Gas Industry. The Venturi meter is a favoured device for the metering of the unprocessed wet natural gas production flows. Wet gas is defined here as a two-phase flow with up to 50% of the mass flowing being in the liquid phase. Metering the gas flowrate in a wet gas flow with use of a Venturi meter requires a correction of the meter reading to account for the liquids effect. Currently, most correlations in existence were created for Orifice Plate Meters and are for general two-phase flow. However, due to no Venturi meter correlation being published before 1997 industry was traditionally forced to use these Orifice Plate Meter correlations when faced with a Venturi metering wet gas flows. This paper lists seven correlations, two recent wet gas Venturi correlations and five older Orifice Plate general two-phase flow correlations and compares their performance with new independent data from the NEL Wet Gas Loop with an ISA Controls Ltd. Standard specification six inch Venturi meter of 0.55 beta ratio installed. Finally, a new correlation is offered.     

Coriolis mass flow metering for three-phase flow: A case study

Previous work has described the use of Coriolis mass flow metering for two-phase (gas/liquid) flow. As the Coriolis meter provides both mass flow and density measurements, it is possible to resolve the mass flows of the gas and liquid in a two-phase mixture if their respective densities are known. To apply Coriolis metering to a three-phase (oil/water/gas) mixture, an additional measurement is required. In the work described in this paper, a water cut meter is used to indicate what proportion of the liquid flow is water. This provides sufficient information to calculate the mass flows of the water, oil and gas components. This paper is believed to be the first to detail an implementation of three-phase flow metering using Coriolis technology where phase separation is not applied.Trials have taken place at the UK National Flow Standards Laboratory three-phase facility, on a commercial three-phase meter based on the Coriolis meter/ water cut measurement principle. For the 50 mm metering system, the total liquid flow rate ranged from 2.4 kg/s up to 11 kg/s, the water cut ranged from 0% to 100%, and the gas volume fraction (GVF) from 0 to 50%. In a formally observed trial, 75 test points were taken at a temperature of approximately 40 °C and with a skid inlet pressure of approximately 350 kPa. Over 95% of the test results fell within the desired specification, defined as follows: the total (oil+water) liquid mass flow error should fall within ±2.5%, and the gas mass flow error within ±5.0%. The oil mass flow error limit is ±6.0% for water cuts less than 70%, while for water cuts between 70% and 95% the oil mass flow error limit is ±15.0%.These results demonstrate the potential for using Coriolis mass flow metering combined with water cut metering for three-phase (oil/water/gas) measurement.     

Electric spark discharge as an ultrasonic generator in flow measurement situations

In this paper, a gap discharge approach to create acoustic signals for ultrasonic low pressure gas flow measurements is investigated. The objective is to develop an ultrasonic gas flow meter system that is capable of operation in extreme industrial environments. These environments might have extremely high temperatures (1200 °C), moisture, steam, dust, low gas pressure and large transmission distances.Most other types of ultrasonic transducers found show sensitivity to such conditions: their operation suffers, or they may even stop functioning if exposed to such environments. The development of new transducer technology is therefore crucial to allow ultrasonic flow measurements in extreme industrial environments. In this paper, the gap discharge emitter is evaluated as a candidate to be used in these applications. Its capabilities as a sound source are investigated, and its impact on flow meter performance is estimated. It can be concluded that, despite the uncertainties it introduces to a flow meter system, it stands out as a strong candidate to be used as an acoustic emitter in a gas flow meter system for extreme environments.