EXHAUSTING MACHINERY
495
■a certam amount of favour on the Continent. First introduced by Cleland, the steam jet was afterwards improved by Körting, and is seen in Fig. 304. Steam at about 50 Ib. pressure is pro-j ected through a series of truncated cones grad-nally increasing in size. The gas is drawn in
through spaces at the nozzles of the cones and is carried forward by the pressure of the steam. Gare should be taken to ensure that dry steam only is used, and this is afterwards extracted from the gas by conden-sing apparatus. The capacity of the exhauster may be regulated within comparatively wide limits by an adjustable needle-valve at the steam inlet, and by a movable sleeve which opens or closes the gas inlet ports. The chief merits of this type of exhauster are that pulsation is entirely avoided, and there are no con-•stantly moving mechani-■cal parts to give rise to wear and tear. On the other hand, there is the ■expense o f providing additional condensers, wnilst steam consumption is high. The jet maybe interposed a t various
points in tlie series of apparatus.
In some cases it is
Fic. 304.—Steam-Jet Exhauster.
preferred to place it in tlie