History of FloScan Aircraft Flow Transducers

In 1972, Aerosonics, (a leading U.S. avionics manufacturer at the time) began testing the Series 200 flow transducers to determine its suitability for use in general aviation aircraft. Prior to that time there had not been a generally acceptable transducer for this application. The company required a fuel flow transducer which would withstand the vibration of an aircraft engine. It also had to meet the important FAA regulation regarding blocked rotor pressure drop which could not be more than 1.5 times the spinning rotor pressure drop.  Our design far surpassed the test requirement since a blocked rotor does not change the pressure drop of a FloScan flow transducer.  For this reason, and because of their superior accuracy and extraordinary repeatability, FloScan transducers quickly become the dominate fuel flow measuring sensors for general aviation with over 250,000 units sold.  In fact, the pilots of the record breaking, non-stop around-the-world flight of the "Voyager" in 1986, depended on FloScan transducers for accurate fuel flow measurement.

Series 200 Flow Sensor Specifications

Description:
Series 200 Turbine Flow Transducers measure flows of hydrocarbon fuels such as gasoline, kerosene, and #2 diesel fuel and other light transmitting, non-corrosive liquids of similar viscosity.  Typical fuel flow applications include aircraft fuel monitoring systems; gasoline, diesel, and gas turbine engine test stands; and industrial furnaces.

The transducers give repeatable signals on gasoline across a 100 to 1 flow range down to 0.3 GPH.  The higher viscosity of diesel fuel reduces signal repeatability at flow rates below 2 GPH.  Pressure drops are very low compared to other turbine flow transducers.  The transducer bearing system is rated for continuous operation at the upper end of the flow range.

The transducers produce a current pulse signal from an opto-electronic pickup with a preamplifier. 

Principal of Operation:
Liquid enters the flow chamber tangentially, follows a helical flow path, and exits vertically, thereby venting any entrained vapor bubbles.  The rotational velocity of the liquid is directly proportional to flow rate.  A neutrally buoyant rotor spins with the liquid between V-jewel bearings.  Rotor movement is sensed when notches in the rotor interrupt an infrared light beam between an LED and phototransistor.

The vapor venting design requires that the transducer be positioned with the electrical connectors pointing up.  Turbulence caused by valves or sharp elbows mounted close to the transducer inlet can affect transducer K-Factor and should be minimized.

Performance Specifications:

NOTE:  All flow transducers are tested and marked with K-factor at 16 GPH.  Repeatability at 16 GPH is guaranteed to ½%.  Transducers are available with calibrated K-factors at additional cost.

 
Material Specifications:

Dimensions (inches)                         *click on diagram to enlarge picture*

NOTE: FloScan reserves the right to change flow sensor specifications without notice.


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