| 摘要 |
A control unit (32) governs compressed air supply to a siren, and apart from a valve (41) which alternately taps high pressure containers, has a reduction valve (44), together with a magnet valve (47), controlled by external signals, for transmission of air impulses at reduced pressure to the siren. In the control unit is a pressure monitor (46a) which provides signals if the air pressure is too low. The high pressure container unit and the control are built into a lockable box with an inspection hatch for connection of signal lines (33) coming from outside. A two-way valve (48) is inserted downstream of the magnet valve in the low pressure air line (46), which when the siren is disconnected may conduct compressed air impulses to a noise damper (49). The control signals are transmitted via telephone lines (33), and a control plinth (35) which locks the box contains telephone jacks (36). |
