Leakage volume

Table 9.11 gives the upper limits of the leakage volume flow rate for the three ductwork classes at typical test pressures. 

The other consequence of the microcirculation is gob breathe. Gob breathe is described as periodical variation of air leakage volume, air pressure and gas composition in the gob. Evolution of relative air pressure attained from 1301 gob in Geting coal mine from February to March is presented in Table 1 where—stands air-in and -i-denotes air-out. 

The amount of inerts which has to be removed by a pumping system after the pump-down stage depends on the in-leakage of air at the various fittings, connections, and so on. Air leakage is often correlated with system volume and pressure, but this approach introduces uncer-... 

The suction gas which enters from the periphery is trapped by the scrolls. The closed volumes move radially inward until the discharge port is reached, when vapor is pressed out. The orbiting scroll is driven by a short-throw crank mechanism. Similar to screw compressors, internal leakage should be kept low, and is occurring in gaps between cylindrical surfaces and between the tips of the involute and the opposing scroll base plate. 

A = leakage area of single throttling, sq ft P(, = absolute pressure before the labyrinth, Ib/sq ft Vo = speeifie volume before the labyrinth, eu ft/lb Pfi = absolute pressure after the labyrinth, Ibf/sq ft n = number of lands... 

To determine the amount of air leak in an existing system, estimate the total volume of the system. Operate the ejector to secure a pressure somewhat less than 15 inches Hgabs. Then isolate the ejector from the system. Measure the time required for a rise in pressure in the vessel (say 2 inch Hg). It is essential that the absolute pressure does not rise above 15 inches Hg abs during this time. The following formula will then give the leakage ... 

If the volume of the system is not known, the leakage can still be determined, but two tests will be required. 

Because there is no clearance volume expansion, as in the reciprocating compressor, the volumetric efficiency is a function of the rotor slip. This is the internal leakage from the higher pressure to the lower pressure side, reducing potential volume capacity of the compressor. 

Evaporation of a relatively-small volume of liquid in an enclosed space can produce a flatmuable or toxic vapour hazard. Leakage, or spillage, of a chemical maintained as a liquid above its atmospheric boiling point by pressure (e.g. liquefied petroleum gases) or as a liquid by refrigeration (e.g. ammonia) can result in a sizeable vapour cloud. 

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