Contacting devices, classification

Electrical switches, relays, and other devices are described for safety reasons by several general categories. Since these devices are potential sources of ignition during normal operation (for example, arcing contacts) or due to malfunction, the area classification limits the types of devices which can be used. 

If the pumps are located indoors, a Division 1 classification is likely to apply. Motors must be Class 1, group D, explosion-proof, or they may be separately ventilated with clean outside air brought to the motor by fans. Auxiliary devices such as alarm contacts on the motor must be suitable for the area classification. The installed costs, overall efficiencies, and service factors associated with the enclosures that are available will influence the selection. 

The classification system uses three basic criteria, in various combinations duration of contact with the body, degree of invasiveness and the anatomy affected by the use of the device. 

Sensor systems are composed of the sensor, the transmitter, and the associated signal processing. The sensor measures certain quantities (e.g., voltage, current, or resistance) associated with devices in contact with the process such that the measured quantities correlate strongly with the actual controlled variable value. There are two general classifications for sensors continuous measurements and discrete measurements. Continuous measurements are, as the term implies, generally continuously available, whereas discrete measurements update at discrete times. Pressure, temperature, level, and flow sensors typically yield continuous measurements, whereas certain composition analyzers (e.g., gas chromatographs) provide discrete measurements. 

Classification Oxazine color Empirical C34H22CI2N4O2 Properties M.w. 589.49 Toxicology TSCA listed Uses Colorant, pigment for plastics, paints/coatings, inks, lacquers, hair dyes colorant for contact lenses Regulatory FDA 21 CFR 73.3107, exempt from certification, permanentiy iisted for use in medical devices... 

Generally, Class III devices affect the functioning of vital organs and/or life-support systems, whereas Class I devices are noninvasive and do not come into contact or interact with the human body. Classifications are assigned by the risk that the medical device presents to the patient and the level of regulatory control which is needed to market the device legally. 

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