Annubar flow meter

Introduction

Application

Technical Data

Installation

Introduction

The Differential-pressure flowmeter is made up of the throttling device, differential transmitter and flow accumulator. The throttling device is a primary element installed on the pipeline, mainly applied in measuring the flow of all kinds of gases (which is pure or containing dust), steams (which is saturated or superheated) and liquids (which is conductive or non-conductive, of strong corrosivity, sticky, smudged or containing particles, etc.), and can measure the volume flow or quality flow directly.

Advantages

The Throttling device is the earliest adopted method of the flow measurement with the longest history, and is the most widely used method at present. Its main advantages are as follows:

For Standard Throttling Devices, there is no need to calibrate the real flow to determine its measurement accuracy (and it is the only flow instrument at present).
The applications of measurable mediums of the throttling device are very large. They are almost applied in measuring the flow of all the gases, steams and liquids.
The range of the pipe caliber is also very wide, which is from Φ 2~Φ3000 mm or over Φ3000. Those cross-sectional shapes which are round or rectangular are all ok.
Its working pressure can reach 32 MPa and can be also applied to the subatmospheric pressure.
Temperature range of mediums: -185^oC ~ + 650^oC (which is impossible for other flowmeters.
There are many kinds of structures of Non-Standard Throttling Devices, which can be almost applied in measuring the flow of all kinds of fluids.
The range of the flow can be changed on the spot by setting the span of the Differential-pressure transmitter.
Its operation and use are very simple and can be mastered easily. Besides, its daily maintenance is very little.

Application

The flowmeters of the averaging tube series have differential pressure working principles and plug-in working methods. They can be used for flow measurement of gases, liquids, and steam. Commonly used averaging tube flowmeters include Verabar flowmeters, Deltabar flowmeters, and Aniu flowmeters. Bar flowmeter, all flowmeters of this type are based on the pitot tube principle. After structural optimization, they have evolved into these types of flowmeters. Their structures are basically the same and they all have the following features: simple structure, small pressure loss, easy installation and maintenance With outstanding advantages such as convenience and significant energy saving, it is a high-precision flowmeter that can be used under quite harsh working conditions and maintain good measurement performance.

Electric Power

Petrochemical

Ceramics

Building Materials

Meausre Dry Gas

Water Treatment

Technical Data

Working theory
The working theory of the flow measurement of the throttling device is based on the famous Bernoulli Hydrodynamic Theory. As shown in the below figure (1), if one throttling element is put in the pipeline, a Differential-pressure (Differential-pressure P) will be produced on both sides of the throttling element when there are liquids flowing through the throttling element, and the flow at this time is in proportion to the square root of the differential pressure, that’s to say,
Volume Flow: QV = A *C / √ (1-β4 ) * ε * d2 * √ (ΔP/ρ )
In the formula,
A----refers to the constants;
C---refers to the effluent coefficient;
β---refers to the diameter rate (=D/d);
d---refers to the hole caliber of the throttling element (mm);
ε---refers to the expansive coefficient;
ΔP--- refers to the Differential-pressure between the front and back of the throttling element (Pa);
ρ---refers to the density of the fluid in the working state (Kg/m3).

Figure (1) Measurement Theory of Throttling Devices

Technical Parameters

Fluids	Gas/Steam	Liquid
Accuracy	±1.5%	±1.0%
Repeatability	0.3%	0.2%
Pipeline size	DN80-DN2000
Ratio Range	≥10:1
Operation Pressure	≤42 Mpa
Fluids Temperature	≤800℃
straight Pipelines	Upstream 7-24D,downstream 3-4D

Installation

Split installation
Split installation	Clean liquid flow measurement	Clean gas flow measurement	Steam flow measurement in horizontal pipelines
Integrated installation
Integrated installation	Gas flow measurement	Liquid flow measurement	Steam flow measurement in horizontal pipelines
liquid		gas	Vertical pipeline
Horizontal line