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 could be made up of metal oxide and polymer elements, both of which exhibit a modification of resistance when in contact with Volatile Organic Compounds (VOCs). In this particular report only Metal Oxide Semi-conductor (MOS), Load Cell and Quartz Crystal Microbalance (QCM) will be examined, as they are well researched, documented and established as essential element for various machine olfaction devices. The application, in which 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 really a device for measuring and recording the torque over a rotating system, such as an engine, crankshaft, gearbox, transmission, rotor, a bicycle crank or cap torque tester. Static torque is relatively simple to measure. Dynamic torque, on the other hand, is difficult to measure, because it generally requires transfer of some effect (electric, hydraulic or magnetic) from your shaft being measured to some static system.
A good way to accomplish this is to condition the shaft or a member linked to the shaft with several permanent magnetic domains. The magnetic characteristics of such domains will vary according to the applied torque, and therefore can be measured using non-contact sensors. Such magnetoelastic torque sensors are typically employed for in-vehicle applications on racecars, automobiles, aircraft, and hovercraft.
Commonly, torque sensors or torque transducers use strain gauges placed on a rotating shaft or axle. With this particular method, a method to power the strain gauge bridge is essential, as well as a means to have 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 and an A/D converter for the rotating shaft. Stator electronics then read the digital signals and convert those signals to Miniature Load Cell, like /-10VDC.
A much more recent development is using SAW devices linked to the shaft and remotely interrogated. The stress on these tiny devices as the shaft flexes could be read remotely and output without resorting to attached electronics on the shaft. The probable first use in volume will be in the automotive field as, of May 2009, Schott announced it features a SAW sensor package viable for in vehicle uses.
Another way to measure torque is by means 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 the two. This method is utilized inside the Allison T56 turboprop engine.
Finally, (as described inside the abstract for US Patent 5257535), when the mechanical system involves a right angle gearbox, then your axial reaction force experienced by the inputting shaft/pinion could be related to the torque gone through by the output shaft(s). The axial input stress must first be calibrated from the output torque. The input stress can be simply measured via strain gauge measurement of 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 is a key component to get accurate measurements. However, improper installing of the torque sensor can harm the device permanently, costing money and time. Hence, cdtgnt torque sensor needs to be properly installed to make sure better performance and longevity.
The performance and longevity from the torque sensor as well as its reading accuracy will be affected by the style of the Force Transducer. The shaft becomes unstable in the critical speed in the driveline and results in 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 point is typically the weakest reason for the sensor structure. Hence, the torque sensor is purposely designed to be one of the weaker elements of the driveline.