There are a number of different types of sensors which can be used as essential components in various designs for machine olfaction systems. Electronic Nose (or eNose) sensors fall under five categories, conductivity sensors, piezoelectric sensors, Metal Oxide Field Effect Transistors (MOSFETs), optical sensors, and these employing spectrometry-based sensing methods.
Conductivity sensors might be composed of metal oxide and polymer elements, both of which exhibit a change in resistance when exposed to Volatile Organic Compounds (VOCs). Within this report only Metal Oxide Semi-conductor (MOS), Load Cell and Quartz Crystal Microbalance (QCM) is going to be examined, because they are well researched, documented and established as vital element for various types of machine olfaction devices. The applying, in which the proposed device will be trained onto analyse, will greatly influence the choice of sensor.
A torque sensor, torque transducer or torque meter is a device for measuring and recording the torque on a rotating system, like an engine, crankshaft, gearbox, transmission, rotor, a bicycle crank or cap torque tester. Static torque is fairly very easy to measure. Dynamic torque, on the contrary, can be difficult to measure, as it generally requires transfer of some effect (electric, hydraulic or magnetic) through the shaft being measured to a static system.
A good way to make this happen is always to condition the shaft or a member attached to the shaft with a number of permanent magnetic domains. The magnetic characteristics of those domains will vary in accordance with the applied torque, and so could be measured using non-contact sensors. Such magnetoelastic torque sensors are generally used for in-vehicle applications on racecars, automobiles, aircraft, and hovercraft.
Commonly, torque sensors or torque transducers use strain gauges put on a rotating shaft or axle. Using this method, a method to power the strain gauge bridge is essential, as well as a way to receive the signal from the rotating shaft. This is often accomplished using slip rings, wireless telemetry, or rotary transformers. Newer kinds of torque transducers add conditioning electronics plus an A/D converter for the rotating shaft. Stator electronics then look at the digital signals and convert those signals to Micro Load Cell, including /-10VDC.
A more recent development is the use of SAW devices connected to the shaft and remotely interrogated. The strain on these tiny devices since the shaft flexes could be read remotely and output without the need for attached electronics on the shaft. The probable first utilization in volume are usually in the automotive field as, of May 2009, Schott announced it possesses a SAW sensor package viable for in vehicle uses.
An additional way to measure torque is through twist angle measurement or phase shift measurement, whereby the angle of twist as a result of applied torque is measured by using two angular position sensors and measuring the phase angle between them. This method is utilized in the Allison T56 turboprop engine.
Finally, (as described within the abstract for US Patent 5257535), in the event the mechanical system involves a right angle gearbox, then this axial reaction force gone through by the inputting shaft/pinion could be linked to the torque experienced by the output shaft(s). The axial input stress must first be calibrated up against the output torque. The input stress can be simply measured via strain gauge measurement from the input pinion bearing housing. The output torque is easily measured employing a static torque meter.
The torque sensor can function such as a mechanical fuse and it is a key component to obtain accurate measurements. However, improper installation of the torque sensor can damage the device permanently, costing money and time. Hence, cdtgnt torque sensor must be properly installed to ensure better performance and longevity.
The performance and longevity in the torque sensor as well as its reading accuracy is going to be affected by the appearance of the Force Transducer. The shaft becomes unstable at the critical speed from the driveline and causes torsional vibration, which can damage the torque sensor. It is actually required to direct the strain for an exact point for accurate torque measurement. This aspect is normally the weakest reason for the sensor structure. Hence, the torque sensor is purposely created to be one of the weaker components of the driveline.