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 Hot wire gas flowmeter (hot wire anemometer)
一、General
L.V.King founded the measuring and calculating method of the hot wire gas flowmeter sensor. In recent years, with the application of computer and the improvement of calculating speed, the theory of L.V.King just has the use value.
The flowmeter made by L.V.King theory has the features such as fast responses, simple structure, without movable components, so it has a long life and needs little maintenance. At present, hot wire flow measurement is the focus. It cannot only measure gas, also can measure liquid, such as Auto air flowmeter, it can control the proportion of the oil and air to attain the optimal burning, reducing the environmental pollution and economizing fuel. The proportion control of air input and coal of power plant boiler, the best control of air quality and aeration, energy economization in air condition room. the flux of gas during peak and valley period can be measured exactly with the hot wire flowmeter; with the hot wire flowmeter and anemometer, the displacement change can be monitored, the information of spare parts and maintenance can be mastered.
Here are the following problems on whether the hot wire flowmeter can be developed successfully or not:
1、The flowmeter structure, circuit and software design.
2、The sensor need to be stable and aseismatic for long term. Repeatability≤0.5%( integral flowmeter)
3、The response speed mainly depends on the sensor.
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| Industrial flow sensor |
Industrial flow sensor |
Industrial flow sensor |
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Industrial flow sensor
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Motorcar airflow sensor High response airflow sensor
（Patent Number：200620092209.6） |
Pt20 high response stainless steel pipe closed flow sensor |
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| Liquid flow sensor |
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二、Direct heated type hot wire sensor
Direct heated type hot wire sensor is developed from the patent technology of platinum resistance of our plant. The platinum wires are wrapped on special ceramic framework, then covered by ceramic and sintered to a integral body, then carries ageing treatment.
The platinum wires of the direct heated type hot wire sensor have two functions. They can not only induce external medium flow speed, but also confirm the instant temperature of hot wire by its resistance. Four-wire system is better. Two are current circuit, the other two are voltage measuring wires. Voltage/current is this component’s resistance value Rt under this heating current，that is Rt=Vi/Iio.
There is tolerance among the Ro value and A，B parameter of the same batch platinum resistance. All the sensors using for industry were marked the corresponding parameters (Ro, A, B) (the Auto air flowmeter is not marked the parameter).The customers can calculate the heating temperature of the components according to the formula
then calculate the flow in the pipe according to the parameter such as flow temperature and dimension measured by the other components.
三、Notice for ordering：
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Confirm the measuring range
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Temperature of operating environment (≤200℃,≤400℃)
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Pressure of operating environment
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Gas quality (caustic or not)
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External drawing
Note : Please order few samples at the first trial-production in order to avoid waste.
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