| 摘要 |
1,128,250. Measuring air leakage electrically. R.J. REYNOLDS TOBACCO CO. Dec. 16, 1966 [Jan. 20, 1966], No.56527/66. Heading G1N. [Also in Division A2] In an apparatus of the type in which cigarettes are tested for leaks by subjecting the interior of a cigarette to air under pressure different from the pressure outside the cigarette, said air being supplied through retractable tube means mounted in one end plate of a rotating cigarette-transporting suction drum, and variations in air flow caused by leaks in a cigarette are sensed, the sensing means comprises a heated wire of substantial temperature coefficient of resistance connected to one leg of a conventional bridge circuit, and the out of balance current is amplified and applied to a relay that actuates a cigarette rejection mechanism. In one embodiment, air flows through the cigarette from one end to the other, in the absence of leaks, and thence passes first through a filter and then through the hot wire sensor to atmosphere. Ejection of faulty cigarettes is effected by air pressure, while normal cigarettes are retained on the drum by suction. In another embodiment, air at constant pressure is passed first over the sensor housed in the common (upright) leg of a "T" branched conduit and is then fed via the other two legs of the conduit to both ends of the cigarette to be tested, little or no air flowing in the absence of leaks. In a modification of the latter embodiment, the common conduit includes a throttle and beyond this a branch conduit leading via the sensor to atmosphere. |
