A USEFUL EXTRA-AIR VALVE.
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The advantages of the extra-air valve are now fairly well understood by most users of commercial transport. Undoubtedly, appreciable saving in the consumption of petrol can be effected by the intelligent use of a fitting of this kind, that is, in the first place, of proper design and is capable of ready adjustment.
The Arc extra-air valve is now being handled exclusively from the London office of the W. H. Wells Manufacturing Co. at 94, Great Portland Street. This valve, which is made in a large number B26 of different patterns to fit many types of induction manifold without drilling or • machining, is one of the most successful
and well-tried fittings of this type on the market The designers claim to have overcome the two commonest shortcomings of extra-air inlets. By making the flanges and the valve barrel from a onepiece gunmetal casting all danger of leakage of air through screwed or other joints is entirely obviated, and by admitting the air to the induction stream through a very large number of small holes placed around the periphery of the flange perfect mixture of the extra-air stream—" atomization," as it is loosely called—is ensured.