GB1304343A - - Google Patents

Abstract

1304343 Testing cigarette rod MOLINS MACHINE CO Ltd F POCOCK and I Y HIRSH 29 Jan 1970 [31 Jan 1969] 5305/69 Heading A2C [Also in Division G1] Inadequately filled cigarette rod is detected by a device comprising a chamber through which the rod is passed and to which air is supplied at a pressure sufficient to compress slightly an inadequately filled rod, means to produce pressure differences at spaced positions along the rod as a result of leakage between the rod and a surrounding part of the device, and a pressure comparator which produces a correction signal in response to an inadequately filled portion of rod. The correction signal may activate mechanism which ejects inadequately filled cigarettes subsequently severed from the rod and/or means for adjusting the tobacco feed to the rod. In one embodiment the cigarette rod 10 passes in succession through a measuring chamber 14, a pressure chamber 4 in which any inadequately filled rod is compressed slightly, and a measuring chamber 16, the two measuring chambers being fed through restrictions 22 with air at a lower pressure than that supplied to the chamber 4, and the pressures in the chambers 14, 16, determined by the annular clearances where the rod passes through the chamber walls, are fed to a comparator 32, which may consist of a diaphragm operating an electric switch, or a pair of coaxial, interconnected diaphragms acting on a movable core of an inductance or transformer. A delayed-action device may be included in the comparator so that the comparison is made on the same part of the rod. In a modification, Fig. 3 (not shown), the three chambers 4, 14, 16 are fed from a common air supply and are defined by washers or rings spaced in a tubular housing. The two measuring chambers 14, 16 may be dispensed with in a further modification, Fig. 2 (not shown), in which the rod enters and leaves the chamber 4 through Venturi-shaped openings the throats of which have tappings leading to the comparator which in this case may be of fluidic type. The apparatus may be adapted to test cut cigarettes instead of continuous rod, and may include means to compensate for the effect of tobacco moisture content on the firmness of the rod.