Safe operating areas

Snubbers are passive networks that delay the risetime of the voltage waveform. Historieally, snubbers have been used to keep power deviees within their forward- and reverse-biased safe operating areas (FBSOA and RBSOA) or to eontrol RF emissions from the power supply. They are essentially lossy tank eireuits (L-C eireuits with R). Using them offered more of an advantage than the loss ineurred. Semieonduetor eomponents are more rugged today and the traditional need for the RFC snubber for proteetion has lessened, but oeea-sionally a snubber is still needed. 

Figure 5.22 Safe operating area curve from ON Semiconductor 2N3055 datasheet.

All lithium-ion (Li-ion) batteries require a BMS. This is due to the fact that all Li-ion batteries will fail if overcharged, completely discharged or operated outside their safe temperature window. Each Li-ion cell type has its own safe operating area, which makes it necessary to program the BMS accordingly. Figure 15.1 shows the safe operating area typical for a C/lithium iron phosphate cell. 

FIGURE 15.1 Safe operating area of a OLiFeP04 cell. 

Charge control limits the rate at which the electric current is fed into each cell to hold the battery in the safe operating area. Additional functions could include communication with external smart charger and reporting of required charging parameters as well as battery state. 

Maximum power dissipation, Po = (Vn — Vburl ouT cannot be exceeded without risking damage to the regulator. The allowable combinations of output current and voltage differentials are sometimes referred to as safe operating area (SOA). 

Personnel Selection and Training. The quaHty of operating personnel is of paramount importance to the safe operation of a chemical plant. Operators must be intelligent and emotionally stable. Excessive use of alcohol and dmgs affects reHabiHty and can thereby render workers more susceptible to certain types of toxic exposure. Thorough medical screening is essential to avoid damaging exposures to susceptible individuals, eg, people with respiratory ailments should not be employed in areas where corrosive atmospheres could occur. 

Vertical Pressure Leaf Filters are essentially the same as Horizontal Plate Filters except for the orientation of the filter elements which are vertical rather than horizontal. They are applied for the polishing slurries with very lov solids content of 1-5% or for cake filtration with a solids concentration of 20-25%. As with the horizontal plate filter the vertical leaf filters are also well suited for handling flammable, toxic and corrosive materials since they are autoclaved and designed for hazardous environments when high pressure and safe operation are required. Likewise, they may be readily jacketed for applications whenever hot or cold temperatures are to be preserved.The largest leaf filters in horizontal vessels have a filtration area of 300 m and vertical vessels 100 m both designed for an operating pressure of 6 bar. 

Nutsche filters are well suited for handling flammable, toxic, corrosive and odor-noxious materials since they are autoclaved and designed for use in hazardous and ex-proof environments when extremely safe operation is required. They are available in almost any size with the larger machines for a slurry filling batch of 25 m and a cake volume of 10 m Such filters have a filtration area of 15 m and are suitable for fast filtering slurries that produce readily 0.5 m thick cakes. The basic configuration is shown in Figure 11. 

More inclusive is Table 3.3.1 -3 which is appropriate at depth into the analysis. The major headings in this table address major hazardous subject areas,. iccideni mitigation, protection and repair. I or example, under the first major heading, "Storage of Raw Materials, Products, Intermediates," listed are confinement measures, release nicclumi.sms (valves), procedures for safe operation and limitations that must be observed for safety. 

The high-pressure oil flows in piping through a control valve. The control valve changes the direction of oil flow. A relief valve, set at a desired, safe operating pressure, protects the system from an over pressure condition. The oil that enters the cylinder acts on the piston, with the pressure acting over the area of the piston, developing a force on the piston rod. The force on the piston rod enables the movement of a load or device. 

Smoking must not be permitted in areas where flammables or toxic substances are used. The laboratory operator should provide for a safe smoking area, generally one where food may also be consumed. In work areas where smoking is permitted, inexpensive ashtrays should be used. They are more practical than Petri dishes. 

Personnel areas Group units Locate personnel areas away from hazardous process and storage areas. Group units in rows. Design for safe operation and maintenance. Create islands of risk by concentrating hazardous process units in one area. Space units so hot work can be performed on one group while another is operating. 

Distribution mains shall be patrolled in areas where necessary to observe factors that may affect safe operation. The patrolling shall be considered in areas of construction activity, physical deterioration of exposed piping and supports, or any natural causes that could result in damage to the pipe. The frequency of the patrolling shall be determined by the severity of the conditions that could cause failure or leakage and the subsequent hazards to public safety. 

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