There are a number of different types of sensors which can be used as essential components in numerous designs for machine olfaction systems. Electronic Nose (or eNose) sensors fall into five categories, conductivity sensors, piezoelectric sensors, Metal Oxide Field Effect Transistors (MOSFETs), optical sensors, and these employing spectrometry-based sensing methods.
Conductivity sensors could be made from metal oxide and polymer elements, each of which exhibit a change in resistance when subjected to Volatile Organic Compounds (VOCs). Within this report only Metal Oxide Semi-conductor (MOS), Load Sensor and Quartz Crystal Microbalance (QCM) is going to be examined, since they are well researched, documented and established as vital element for various types of machine olfaction devices. The application, where the proposed device will likely be trained on to analyse, will greatly influence deciding on a sensor.
A torque sensor, torque transducer or torque meter is actually a device for measuring and recording the torque on a rotating system, such as an engine, crankshaft, gearbox, transmission, rotor, a bicycle crank or cap torque tester. Static torque is relatively easy to measure. Dynamic torque, on the other hand, is not easy to measure, because it generally requires transfer of some effect (electric, hydraulic or magnetic) from your shaft being measured to your static system.
A good way to make this happen is always to condition the shaft or even a member connected to the shaft with several permanent magnetic domains. The magnetic characteristics of such domains can vary in accordance with the applied torque, and so can be measured using non-contact sensors. Such magnetoelastic torque sensors are usually used for in-vehicle applications on racecars, automobiles, aircraft, and hovercraft.
Commonly, torque sensors or torque transducers use strain gauges applied to a rotating shaft or axle. With this particular method, a method to power the strain gauge bridge is necessary, as well as a methods to receive the signal through the rotating shaft. This could be accomplished using slip rings, wireless telemetry, or rotary transformers. Newer types of torque transducers add conditioning electronics and an A/D converter towards the rotating shaft. Stator electronics then look at the digital signals and convert those signals to Micro Load Cell, including /-10VDC.
A far more recent development is the use of SAW devices connected to the shaft and remotely interrogated. The stress on these tiny devices because the shaft flexes can be read remotely and output without the need for attached electronics on the shaft. The probable first use in volume are usually in the automotive field as, of May 2009, Schott announced it has a SAW sensor package viable for in vehicle uses.
A different way to measure torque is by way of twist angle measurement or phase shift measurement, whereby the angle of twist caused by applied torque is measured by making use of two angular position sensors and measuring the phase angle between them. This technique is used in the Allison T56 turboprop engine.
Finally, (as described within the abstract for all of us Patent 5257535), if the mechanical system involves a right angle gearbox, then the axial reaction force felt by the inputting shaft/pinion can be linked to the torque felt by the output shaft(s). The axial input stress must first be calibrated up against the output torque. The input stress can be easily measured via strain gauge measurement in the input pinion bearing housing. The output torque is easily measured employing a static torque meter.
The torque sensor can function like a mechanical fuse and is also a key component to obtain accurate measurements. However, improper installing of the torque sensor can damage the device permanently, costing time and money. Hence, cdtgnt torque sensor has to be properly installed to ensure better performance and longevity.
The performance and longevity in the torque sensor along with its reading accuracy will be impacted by the style of the Force Transducer. The shaft becomes unstable at the critical speed from the driveline to result in torsional vibration, which can damage the torque sensor. It is necessary to direct the strain for an exact point for accurate torque measurement. This point is usually the weakest reason for the sensor structure. Hence, the torque sensor is purposely designed to be one of the weaker components of the driveline.