| 摘要 |
<p>A gas distribution system for, e.g. compressed air with a compressor supplying a gas storage vessel, supplying a number of units, each with a control valve. A leak testing system with a pressure sensor (12) operates a switch with contacts (b11, b1) which operate a relay system so that a pair of warning lamps (h1, h2) are actuated. The relay system includes a time delayed relay (d2) in series with a manual switch (b3) so that further parallel contacts (d2V1, d2V2) are actuated so that, when the manual switch is operated, there is a short delay during the period between the operation of the test device and the operation of the indicator lamps. This is caused by a further self holding relay (d1) in series with the others (d2, d3), with a contact (d11) in parallel with one of the contacts (b11) operated by the sensor.</p> |
