This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 edition. Excerpt: ... CHAPTER X IMPROVEMENTS Reasons For Inefficiency. From the preceding chapters it is clear that from whatever point of view pumps and ejectors are considered, the mechanical efficiency of the reciprocating pump is far superior to that of the pneumatic ejector. On the other hand, the merits of the ...
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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 edition. Excerpt: ... CHAPTER X IMPROVEMENTS Reasons For Inefficiency. From the preceding chapters it is clear that from whatever point of view pumps and ejectors are considered, the mechanical efficiency of the reciprocating pump is far superior to that of the pneumatic ejector. On the other hand, the merits of the pneumatic ejector, as an apparatus for raising crude sewage, are so obvious that methods of improving their efficiency are worth some consideration. To spend time and money on obtaining an extra 1 per cent. or 2 per cent. efficiency on the reciprocating pump, when we already have an efficiency of 90 per cent. compared to 40 per cent. of the ejector, is misdirected energy. There is room for very little improvement in the pump, but for a great deal in the pneumatic ejector. Before discussing possible means of improvement, let us first briefly enumerate the reasons why the ejector is so inefficient from the mechanical point of view. The reasons are as follows: 1. The ejector is operated by a secondary power. 2. There is a certain amount of unavoidable loss in the compression of air. 3. The air is used in the ejector without expansion; there is no ' cut off.' 4. The loss of leakage from air mains. 5. Great variation in the volume of air required. 6. Absence of storage. 7. Fluctuation in pressure. 8. Absence of uniform running conditions. If there is an average loss of 6 per cent, or 7 per cent, from each of the above causes, it is easy to see that in the aggregate they mount up to a large figure; and again, that the opportunity for leakage and loss is multiplied a hundredfold in such a system as compared to the simple process of direct pumping. Therefore it may be said, as far as the mechanical efficiency is concerned, the ejector will never equal the...
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
