Compressed-air supply system

948,250. Air compressors. DAIMLERBENZ A.G. Oct. 26, 1962 [Nov. 9, 1961], No. 40668/62. Heading FIN. Apparatus for producing and holding a store of compressed air comprises an air compressor 2 delivering through a non-return valve 6 to a storage vessel 7, a leakage point 11, 111 or 1111 being provided between the non-return valve and the compressor. The latter draws in air through a filter 3 and delivers it through a passage 5, the valve 6 and a passage 51 to the vessel 7. The valve 6 is spring loaded preferably by a relatively weak spring to avoid noise, provision of the leakage point 11, 111 or 1111 ensuring, when the compressor is stopped, that the pressure drop across the non-return valve becomes large enough to fully close the latter. The point 11 may be a bore or a notch in the delivery valve member 9 of the compressor or in its seat 91. The point 111 is a bore in a wall dividing the intake and delivery spaces of the compressor. The point 1111 is a bore in the passage 5 or the housing 14 of the valve 6; the point 1111 may be additional to one of the other points 11 or 111. The points may have a cross-section of 1/10 to 3/10 m.m.