natural gas meter,oxygen flow meter,waste gas flow meter

1. · accurate measurement of flow of fluid media such as liquid, gas, steam and viscous media etc. under various normal temperature, high temperature and low temperature operating conditions;
2. · extremely high sensitivity capable of measurement of ultra small flow (minimum flow that can be measured is 0.08m/s;
3. · no movable part, hence high safety and reliability;
4. · high measurement accuracy and precision (reaching 0.2% for measurement of total quantity);
5. · wide measurement range (reaching 1:30);
6. · good repeatability (normally 0.1~0.08%) and fast measurement;
7. · small pressure loss, only about 1/2P of standard orifice;
8. · dry calibration can be used, i.e. poise hanging method;
9. · target plate can be replaced as required to change flow measurement range;
10. · capable of online direct reading and remote transmission/signaling;
11. · easy installation and very easy maintenance.
12. Anti-interfere, anti-acid, anti-alkaline,anti-impurity

II. Structure and operating principle

1) Structure

SBL flowmeter mainly consists of measurement tube (casing), stress element (target plate), sensing elements (force transducer, pressure transducer and temperature transducer), transition part (adjusted according to temperature and pressure), and accumulation calculation, display and output part. Refer to the following figure for the structure:

Refer to Fig.1 for operation schematic of model SBL target flowmeter with digital display. The stress element (target plate) is placed at center of measurement tube (instrument body) coaxially, with rigid connection with transducers. When measured medium flows at certain velocity (m/s), this medium has certain momentum that directly acts on the stress element (target plate). Due to rigid connection between stress element and transducer, the transducer is subject to direct force F generated by fluid momentum. This force is related to flow velocity V, medium density ρ and area of target subject A to force as follows:

In which:

F——force on target plate

C_D——resistance coefficient

P——fluid density, kg/m³

V——fluid velocity, m/s

A——area of target plate subject to force, m²

Through derivation and conversion, the flow is calculated as follows:

In which

Q_m, Q_V-----mass flow and volume flow respectively (kg/h, m³/h)

α----flow coefficient

D----inner diameter of measurement tube, mm

β----diameter ratio, β=d/D

d----target plate diameter, mm

Other symbols are the same before.

Force on target plate is converted to electric signal by the force transducer. This signal is amplified by pre-amplification and processed by AD conversion and computer, to provide corresponding flow and total quantity. Operating principle is shown as follows:

1. Measurement tube; 2. Target plate; 3. Target rod; 4. Transducer; A. Strain-meter

Table 1

Note: Size of flowmeter flange shall execute GB/T9115.1~9115.4-2000 series standard. For pipeline type, small diameter flowmeter of DN6, DN8, DN10 etc. can be manufactured to user requirements.