Exhaust connection

Fig ure 5-28. Gas exits through the upward-oriented exhaust connection. 

FIGURE 10.38 Downdraft table for ndtn etc. with side walls. This cable has two exhaust connections to distribute the flow over the enure surface. 

If the contaminated airflow rate that is to be exhausted, or the internal pressure, varies too much it could be advantageous to use an exhaust connection with a small distance between tube and duct, acting as an opening for additional air when contaminant flow rare is low. This could be in the form of a large exterior hood covering the outlet from the process and leaving only a very small opening gap for external air (thimble). See Fig. 10.40. 

Equipment and supplies should be placed in the enclosure before a contaminant-generating procedure commences. Unnecessary equipment should be removed. High-input heat sources within an enclosure will cause convection currents that can disturb the flow and should be avoided, if possible, or accounted for with correct placement of baffles and/or exhaust connections. 

Steam inlet neck and exhaust connection a. Material — ... 

Steam inlet neck and exhaust connection a. Maleiial -----------------------------------... 

One end of the tipping cylinder pivots in a devls which is cast as a part of the sujppdrt base. The piston in th e c ylinder is fastened to a bell crank which isi secured to one end bf the receiver cylinder trunnion shaft. Orif i ces in the exhaust connections for the control valves govern the piston sjpeed. The restriction of fluid flow by the orifices cushions the rise and fall of the receiver cylinder. 

Vacuum exhaust connections for the through shuttles are provided at the face of the reactor for the convenience of experimenters in setting up their equipment. These are part of the experimental services normally provided at all beam hole facilities. 

Do not modify fume hoods in any way that adversely affects the hood performance. This includes adding, removing, or changing any of the fume hood components, such as baffles, sashes, airfoils, liners, and exhaust connections. 

The Class II Type A cabinet can have its exhaust connected as an option to the building exhaust. If this connection is made, the cabinet is designated as a Class II Type B3 unit, the B designating an external exhaust connection (see Figure 9.5). The Class II Type B3 cabinet is suitable for work with only trace quantities of explosive, flammable, toxic, or other hazardous substances. 

Type Al (formerly Type A) does not have to be duct vented (although it is possible to connect to building ventilation systems by use of canopy exhaust connections), which makes it suitable for use in laboratories inaccessible to ductwork. This cabinet can be used for use of low to moderate hazard agents that do not include volatile toxic chemicals and volatile radionuclides. The supply air is HEPA filtered to present the sample or media being used with a particulate free air stream with a face velocity of at least 75 fps. This type of BSC caimot be used for volatile and toxic compounds and solvents because small quantities of these materials can quickly load the filter. Type A2 differs from Type Al in that protection of the operator and the environment is only afforded if the exhaust line is canopy vented to the building exhaust. The face velocities of these units are at least 100 fps. 

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