Abstract: A water quality detection device including a detection tank, a sensor, the cleaner and a processor is provided. The sensor is disposed on the detection tank and is configured to sense a to-be-detected liquid within the detection tank. The cleaner is configured to clean the sensor. The processor is electrically connected to the sensor and the cleaner and is configured to: execute an initialization procedure, which includes driving the sensor to sense the to-be-detected liquid to obtain a number of initial sensing values and calculating a threshold value according to the initial sensing values; drive the sensor to sense the to-be-detected liquid to obtain a sensing value of the to-be-detected liquid, and determine whether the sensing value of the to-be-detected liquid reaches the threshold value; drive the cleaner to operate when the sensing value of the to-be-detected liquid reaches the threshold value.

Abstract: A coupling device for coupling two or more ducts together includes a number of frames each having four beams secured together for forming a square shape and for securing onto the ducts. The beams each includes a flange extended upward and each includes a panel formed on each of two ends and inclined relative to the beams. A number of fasteners may secure the panels together for allowing the beams to be secured to the duct. A number of blocks may be engaged between the panels for allowing the beams to be secured to the duct of greater size.