Intrinsically Safe - Fuel Level

INTRINSIC SAFETY

Intrinsic safety (IS) is a protection technique or concept for safe operation of electronic equipment in explosive atmospheres and under irregular operating conditions. The concept was developed for safe operation of process control instrumentation in hazardous areas, particularly North Sea gas platforms. As a discipline, it is an application of inherent safety in instrumentation.

Fuel Level Senders are deamed  intrinsically safe if the available electrical and thermal energy in the system is always low enough that ignition of the hazardous atmosphere cannot occur.  CiES can achieve intrinsic safety in many ways 

• One way of achieving this is ensuring that only low voltages and currents enter the hazardous area, and that all electric supply and signal wires are protected by limited current source.   If wiring to the existing fuel sensors are inside the tank - the following can be applied - the CiES sensor consumes no more than 20 mA and the current source caps the maximum delivered to 50 mA - if a transient voltage were to be introduced the current spike is of extremely short duration.

• The other and more important method CiES Inc. has chosen is to keep all electronics out of the fuel tank.  This insures that "NO Electrical Energy"  would be present in the tank at all .  This is achieved by installing the sensor to the side of the fuel tank and the wires run external to the fuel or fuel hazard.

CIES Inc Fuel Level Sensors have 

passed RTCA DO-160

for Explosive Atmosphere 

CIES Inc Fuel Level Sensors are patented and utilize a magnetoresistive sensor and proprietary electronics to determine the position of a float inside the tank.

CiES Sensors are Intrinsically Safe 

Contact Us

Fuel Level Senders - Automotive

Fuel level sending has been the providence of electrical resistance since somewhere in the 1930's when electrification of the automobile hit full stride.  The Ford Model A used a very clever sight gauge so that you actually saw a liquid representation of fuel level - neat design but expensive.

http://www.facebook.com/Fuellevel

Resistance Level worked very well and was easy to understand  -  X Ohms Full - Y Ohms Empty

Simple

And then suddenly somebody decided to add alcohol -  to fuel -

Methanol and ethanol contain soluble and insoluble contaminants.[5] Halide ions, which are soluble contaminants, such as chloride ions, have a large effect on the corrosively of alcohol fuels. Halide ions increase corrosion in two ways: they chemically attack passivating oxide films on several metals causing pitting corrosion, and they increase the conductivity of the fuel. Increased electrical conductivity promotes electrical, galvanic and ordinary corrosion in the fuel system. Soluble contaminants such as aluminum hydroxide, itself a product of corrosion by halide ions, clogs the fuel system over time. To prevent corrosion the fuel system must be made of suitable materials, electrical wires must be properly insulated and the fuel level sensor must be of pulse and hold type (or similar). In addition, high quality alcohol should have a low concentration of contaminants and have a suitable corrosion inhibitor added.

So if you turn to any car chat blog (ANY CAR CHAT BLOG)  -

Failed fuel level sensors are driving OBD II cars to the shoulder.

So we need to find a replacement  Smiths (Stewart Warner, VDO, Veglia, Et al) in a Pulse and Hold fuel senders - Not compatible 

We are producing  a patented new non-contact fuel level sensor.

We are applying the sensor presently  to aviation (aircraft, rotorcraft) - In aviation we don't have alcohol,  but we can't put wires in the tank - something about electricity and fuel

Aviation  requires - what cars - all cars using Alcohol mixed fuel need - A non contact fuel level sensor

It is also helpful in this environment 

Fuel Level Sensor Under Test

We use a new concept in our sender called Magnetoresistance - certain materials change resistance in the presence of a rotating magnetic field and they can do this from as far as 3/8" away actually from the dry side of the tank.

Most of us see this everyday in the compass on our smartphone

There is no pivot or contact resistance,  so the float can be smaller and the range can be larger (fuller fulls and emptier empties)

Neat thing is that the  output of this sensor  can mimic a resistive sensor

Hey if you find this interesting let us know

scott.philiben@ciescorp.com