The investigation of behaviour of an ejector feeder conveying air alone suggested that
(i) the loss at the ejector increases with decrease of the opening ratio and approaches a constant value as the opening ratio continues to increase, and the pressure at the feed chamber decreases rapidly with increase of the opening ratio and thereafter increases with increasing the opening ratio,
(ii) the jet length is likely to have little effect on the characteristics of the ejector,
(iii) efficiency of the diffuser shows a maximum value at degree of 8,
(iv) the back—pressure of ejector is likely to have little effect on the loss of the ejector, however, the pressure at the feed chamber increases with increase of the back-pressure, and
(v) the pressure at the feed chamber decreases with increase of air rate, while there may be a limit of air rate because air velocity for conveying solids is not excessively high.