| 摘要 |
Device for monitoring the velocity of a gas flow in a duct, in particular for the smoke suction system of a multipoint line smoke alarm. The device has a sensor (10) which is formed by a temperature-sensitive heated element and is arranged directly in the gas flow. The sensor (10) is connected to a temperature compensation circuit (11) which serves for compensating the temperature fluctuations of the gas. A set-point/actual-value comparison circuit (13) serves for monitoring the voltage of the sensor (10), which depends on the velocity of the gas. If the gas velocity over- or undershoots the set-point value which has been set by means of a potentiometer (12), the comparison circuit (13) activates a fault circuit (15) via a time-delay circuit (14). The fault indication is conducted, e.g. to a fire reporting centre. A measurement output circuit (17) serves for setting the limiting value of the gas velocity during commissioning of the device. A heating circuit (20) serves for heating gas suction points should they be blocked by icing. …<??>The device is particularly suitable for monitoring in the case of special applications, e.g. in EDP rooms, high-bay warehouses, or in areas where temperatures are below 0 DEG C. …<IMAGE>… |
