Control of Jet Compressors

The increase of the motive pressure does not only change the pressure ratio along the motive nozzle, but also the mass flow rate calculated by Eq. (4.1) rises. 

A similar effect to the increase of the motive pressure results from an increase of the motive mass flow rate, by increasing the diameter of the motive nozzle. In this case, the values for the critical discharge pressure also grow, while the suction characteristic is virtually unchanged. 

If using a control with an additional ballast load it is normally reasonable to use a bypass from the outlet of the ejector back to the suction side and thus not give an additional external load to the system. For example, when pollutants are in the suction flow and ambient air is sucked in, this air will be saturate with the toxic components and carry them out and pollute the environment. 

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