| 摘要 |
<p>A device (1) is provided for drawing off and replenishing water in the boiler (2) of an espresso coffee machine in such a manner that the water level in the boiler (2) is maintained constant regardless of variations in the water supply pressure. The device includes a draw off cock (6) and a filling cock (7) respectively placed in a boiler outlet pipe (4) and in a boiler inlet pipe (5), these cocks (6, 7) being controlled to open simultaneously. A first throat (21) placed in the outlet pipe (4) has a resistance which is set to give a desired delivery rate of water. A second throat (23) is placed in the inlet pipe (5). In order to provide for equality of water flow through both throats (21, 22) (and thereby ensure that the boiler (2) is replenished at the same rate as it is emptied), a valve (23) is inserted in the inlet pipe (4) to regulate the pressure of water immediately upstream of the second throat such that this pressure is maintained at a value which bears a predetermined relation to the boiler water pressure.</p> |
