摘要 |
<p>The field of the invention is an apparatus for blending two gases together in precisely adjustable proportions. While the advantages of using a gaseous mixture of nitrogen and carbon dioxide in dispensing beer have been known for some time, substantial difficulties have been encountered in designing an accurate, reliable and unexpensive device for mixing the gases in the correct proportions. The apparatus includes a mechanically adjustable blending subassembly (20) adapted to receive the first gas at a predetermined pressure and a one to one force balanced pneumatic relay (18) which is operated by the first gas (14) and which meters the flow of the second gas to the blending subassembly at a pressure substantially equal to the pressure of the first gas being supplied to the blending subassembly.</p> |