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 

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Anisotropic Magneto Resistive - The future of fuel and fluid level detection

A major milestone occurred in 2011 -  the first commercially successful application of Anisotropic Magneto Resistive (AMR) technology applied to fuel level sending.    

We made our technological introduction a critical test for the sending unit as we choose to apply this sender to the most popular GA aircraft built.  It was a gutsy move to use aviation as our launch vehicle, but by all measure and after two years of flawless performance, we can say that this methodology for measuring fuel level has been overwhelming success.

The CiES Fuel Level Sensor is a magnetic, non-contacting angular position sensor that converts rotary motion of the float arm into an electrical signal.
This signal provides an accurate fuel level measurement and enables reliable Multi-Function Display or Fuel Gauge readout.  

Our compact, modular design utilizing the familiar SAE 5 bolt mounting allows a wide range of applications and our calibrated output signal compensates for component and assembly variations.  Our unique design using our patented AMR technology enables dependable performance and durability.


The CiES Fuel Level Sensor's linear output - either Frequency, Voltage or PWM Current Mode  is directly proportional  to the position of the float in the tank.  The we derive this location by the measurement of the magnetic field direction.  This method  allows for wide mechanical tolerances and sensor placement.  Just like a compass in your hand - no matter where or how you move the compass, it will continue to point North - our sensor continues to point at the float.

Noncontact performance is made possible by state-of-the-art  programmable Anisotropic Magneto Resistive (AMR) technologies. Rotating magnets generate a voltage with a paired sine wave response signal.   The sensor operates in a combined linear region of this  sine wave response signal.

Benefits 

• Low cost with electrical interface that powers and reads AMR effect output signal
• Modular and common interface help achieve competitive cost
• Can be easily modified to meet specific customer requirements
• Protection against contamination and fuel exposure
• Lower drive current minimizes system power consumption
• High resolution output signal with low hysteresis for improved system performance

Typical Applications 

The CiES Fuel Level Sensor is ideally suited for a wide range of aviation, automotive, heavy equipment, commercial vehicle, rail in-tank applications for Gasoline, Avgas, Jet A, Propane, Alcohol & Flex Fuel blends.  The non contact measurement method is immune from attack from any sulfur based, water based or solid contaminates.  This method of fuel measurement allows for a single fuel sender  to be applied to a wide variety of fuel types, including different fuels utilized in the same tank, providing the identical output response.

Performance Advantages

The CiES Fuel Level Sensor features a proven technology that has been used in high volume absolute position sensor applications, like brake by wire, throttle and accelerator positioning, for more than 10 years.

The non-contacting design of the sensor maximizes product life by eliminating fuel level signal deterioration due to contact wear, resistive ink failure or dendritic growth.  Our low current draw with high resolution output signal may be calibrated for the angular travel of a specific application and allows us to  compensate for any assembly or tank variations.  

Float Based Sensors - Accuracy Quality Reliability

Float Based Sensors 

These sensors have been in use for a long period of time.  They have a few advantages that are difficult to overcome.   If they have a less than stellar reputation it is more about the electronics used, than the method  of finding a fluid level.    We will assume that quality and good practice

• The float will find the surface 

• Provides a reliable value for full and empty
• Provides a stable output, even under fluid agitation.

• Simple mechanism and controlled motion about a pivot.

• Used everyday in the most critical applications 

• Independent of fluid type or composition

• The singular most popular method for measuring liquid level 

• A float and pivot arm can be maintained for millions of operational cycles 

The typical methodology for finding level is resistance - either in a wound wire or a resistance grid.  The output is simply a distinct resistance value.  However this mechanical method for obtaining an electrical value for fluid level has a few problems.

• This practice introduces a mechanical wear item into the system.  It is this wear on the resistance surface that draws the most criticism.

• The CIES Inc float sensor design has only a pivot to wear - and we can utilize a lighter float as there is limited friction to overcome.

• Resistance needs electrical modification to correlate with volume 

• The CIES Inc. float sensor design is digital output and can be programmed to tank volume 

• Resistance circuits immersed in fluids are susceptible to corrosion from alcohol in gasoline or de sulfered diesel or potentially to the 100LL replacement.

• The CIES Inc. float sensor design sensing element is outside of the fuel compartment no chance for corrosion 

CIES Inc answered the quest  - What if we could combine the simple and effective elements of a pivoted float and replaced the resistance element and its problems from the fuel tank sending system

Only CIES Inc has a patent to combine a sophisticated, reliable and stable sensor technology to a simple float mechanism.

CIES FUELRITE Level Sensor 

Utilizing the patented Anisotropic Magneto Resistive technology allows CIES Inc in an intrinsically safe non contact system.

CIES Inc  effectively married the simplicity and effectiveness of the float based system with a non contact level sensing technology with the following characteristics:

• Effective 
• Accurate
• Sensitive - Measures down to 0.02 Degrees 
• Immune to nearby magnetic fields
• No hysterisis -
• No drift over time or temperature - stable 
• Intrinsically Safe 

A proven system backed by exhaustive testing. 

Let us know your unique application

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Fuel Level Sensors for Collector Vehicles