| 摘要 |
A ventilation system has means to measure the electric current drawn by an extractor fan 12 in order to determine operation and speed of the fan, and also means for automatically isolating a combustion gas supply 18, if the fan is not at the required speed. The ventilation system also has and a manual control unit 28 for the extractor fan including speed adjustment 30. In use, the speed of the fan cannot be manually adjusted below a configured minimum operating speed. The ventilation system may be used in a kitchen ventilation system, with the extractor fan arranged in a hood extractor, and the system may include an air supply fan 10 whose electric power usage is also monitored. The means to determine the fan operating speeds and means to automatically shut down the gas supply may be provided by a control module 14 and an associated gas supply valve 16. The control module may also function to only allow the gas supply valve to admit the combustion gas supply once the fans are running and adequate ventilation is provided. The ventilation system may include further features; such as a remote control button 20 and a fire alarm 24, both of which provide emergency isolation of fans and gas supply; and a differential pressure switch 26 which may be used to monitor the condition of filters through which ventilated air and combustion by-products pass. |
