| 摘要 |
<p>A burglar alarm system for multiple-glazing windows with >=2 window panes, enclosing a dry air space (filled with dried air or contg. a dessicant such as silica gel), is based on arranging inside this space several strips, made of a hygroscopic electrolyte. A pref. material is neutral salt such as MgCl or MgSO. The strips are joined to electrodes which are insulated and form a part of an alarm circuit. This normally carries no current but when a window has been broken, the electrolyte becomes conductive and an alarm is sounded. Such an alarm system cannot be bypassed by a burglar and is less obstructive than wires for an acoustic alarm.</p> |
