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Impeller flow sensor indicator/rate/meter fuel/water uk
PADDLE-WHEEL HALL-EFFECT FLOW SENSOR
A compact flow-transducer component that converts fluid flow-rates into a pulsed output signal.
Similar to RS product: 508-2704 [ 84.15 + vat]
Basic principle: The fluid passes across a 'paddle wheel' impeller containing three ceramic magnets. The rate of rotation of the paddle wheel is proportional to the rate of flow of fluid through the chamber [within limits]. A 'hall effect' sensor sealed in the rear portion of the assembly switches a transistor output as each magnet passes.
Suitable for most fluids: Water, Petroleum Fuels, Light Oils, Alcohols etc.
Please contact me if you need a sensor suitable for measuring the flow of gases or air. And describe your intended application.
Translucent case with visible rotary impeller - gives visual indication of flow.
Ports are very slightly under 10mm external diameter. Can be used with hose or most 10mm push-fit or compression fittings. Internal diameter is 6mm. The ports could possibly be given a 1/8" bsp external thread.
PULSE RATE: The output pulse rate is proportional the flow-rate over a wide range of flow rates. I have tested a sensor over 0.4~5LPM [litres per minute] range. Over this range the sensor gave one pulse per 0.88 cubic centimeter. Or 1140 pulses per litre. But in practice you will find that accuracy and repeatability will be dependent on the range of flow-rates over which you are measuring and other factors such as sudden flow-rate changes, entrained bubbles, fluid viscosity etc.
I expect that the exact rates may differ slightly for different sensors. For greater accuracy it would be best to to calibrate your system using measured quantities of fluid at the flow-rates anticipicated in practice.
Can be mounted in any orientation. And will give an output with flow in both directions.
The following link gives data for a similar hall effect sensor [precise ratings may not be identical to those shown]:
http:// /sheets/tuthill/tuthill_fpp_hefs_spec.pdf
The output is transistor based. In order to give a useful output the user must connect a single external 'pull-up' resistor between the red and blue wires. Please see the pdf link below for a simple wiring diagram and the required resistor value for your application. I will be happy to supply this resistor for free with the sensor - just ask.
The diagram below shows a typical serving suggestion showing a similar type of sensor and the output run to the input of a PLC. I've included this diagram because it helps to see the principle involved. The transistor must not sink more than 20mA. And for many applications where a low current voltage source is all that is required to trigger external circuitry it is OK to use a 6~10K pull-up resistor.
FLUID TOTALISER: requires connection to a pulse COUNTER. User should ensure that the counter can count at the maximum required pulse rate. I have some suitable counters - see below.
FLOW-RATE meter: requires connection to a 'frequency meter' even the Hz setting on a multimeter or 'frequency to voltage converter' and 'volt meter' OR: you can make your own circuit to generate a timed pulse triggered by the leading or falling edge of the sensor output pulse. The timed pulse length would have to be shorter than the minimum expected output pulse cycle. The timed pulses can be fed through to a simple capacitor and discharge resistor arrangement and this will give a voltage on the cap. which will be proportional to the sensor pulse rate. A '555' IC monostable timer circuit would probably be the cheapest and easiest way of generating regular pulses.
Having said this I can offer no guarantees as to whether any particular type or model of bike computer would be compatible with this sensor. I've mentioned the idea here as an idea. But it's a good idea!! More to come on this - I expect!!
I have now listed a small number of totalizing pulse counters that would be suitable for taking readings from this flowmeter. Max input freq. 10kHz. If you are looking for such a counter then see my other listings or search "flow sensor counter".
