GB777623A - Methods of and apparatus for continuously and individually checking articles - Google Patents

Abstract

777,623. Sorting in accordance with transparence to radiation. BERTHOLD, R. [trading as LABORATORIUM PROFESSOR Dr., BERTHOLD], RITTER, W., and KRISTINUS, F., [trading as BRINKMANN KOMM.- GES., M.]. Jan. 7, 1955 [Jan. 7, 1954], No. 618/55. Class 40 (3). In apparatus for separating defective articles in a continuous stream, the articles are fed to individual holders which pass between a source of #,γ or X-radiation and a device sensitive to such radiation, the response of the latter controlling means for rejecting defective articles. The invention is applicable for example to testing ampoules in which case the stream has a step-by-step movement, hard X or γ-radiation is used and the control element is a proportional or triggering counter or a scintillation counter and to articles less dense than cigarettes in which case #-radiation may be used in conjunction with ionization chambers. In the arrangement described, however, which is for cigarettes, the latter are in continuous movement, the radiator is Sr<SP>90</SP> or Ra and the control is exercized by a double counter tube, i.e. in effect two counter tubes in a common casing. Operation. On being severed from the rod the cigarettes fall on to a rotating drum 5, Fig. 3, from which they are transferred to a drum 8 having compartments 15 in which they are carried between a source of #-radiation 25 and one section of a double counter tube 27 and further compartments 38, Fig. 5, which pass between a source 26 of #-radiation and the other section of the tube. The compartments 38 may contain pieces of foil having the same stopping power for the radiation as a perfect cigarette or a fixed foil having the same effect may be mounted between the counter tube and the drum and the compartments 38 may be left empty. Cigarettes found to be defective are marked by the displacement of an associated pin 37, Fig. 4, at one side of the drum and in due course this pin operates a switch 39, 41 to energize an ejecting magnet 43 or a pneumatic ejecting arrangement, Figs. 7 and 8 (not shown). Modified arrangements of the registering pins are referred to. Circuit arrangements. While the voltages on capacitors 110, 111 due to the discharge of the respective sections of the counter tubes are equal, there is no potential difference across resistor 118. When, however, cigarettes deviate from the desired weight, the discharges are unequal and the P.D. developed across 118 is indicated on a meter 120. A large capacitor 122 ensures that the reading indicates the mean deviation of a number of cigarettes. Just before each cigarette enters the radiation beam, a photo-cell 58 with the aid of a thyratron 127 causes momentary operation of a relay 123 to discharge capacitors 110, 111, 112 (110 being discharged slightly in advance). The capacitors are then re-charged in accordance with the response of the counters and if a sufficient P.D. is produced across 118, a thyratron 131 fires in response to a supplementary voltage from capacitor 130 due to the photo-electric impulse initiates the next measuring operation. Anode relay 134 then operates the ejector magnet which closes a contact to restore the anode relay armature.