Patent GB-820364-A (GB)
Title: Method of testing frangible articles
IPC: H01J9/42
Filed: 1955-12-15
Abstract: 820,364. Testing portable containers. CORNING GLASS WORKS. Dec. 15, 1955 [Dec. 16, 1954], No. 36041/55. Class 66. [Also in Groups XI, XXIII and XL(c)] Structurally defective frangible articles of a group of unsorted articles, e.g. electric lamp bulbs or other bulbous glassware, are destroyed by subjecting the unsorted group to sound waves at a frequency and intensity at which experience has shown that defective articles will be destroyed, while avoiding sound frequencies and intensities at which experience has shown that a substantial percentage of the faultless articles will be destroyed. In the examples lamp bulbs 12 are loaded neck downwardly within trays 11 each holding a batch of one hundred bulbs, and the trays are placed upon a conveyer, comprising a pair of parallel endless belts 13 located in a horizontal plane, and fed in succession into a sound-insulated chamber 16. Preferably groups of curtains 17 and 18 are arranged within the chamber near to the entrance and exit of the trays in order to confine within the chamber the sounds produced therein. A vertical cullet shoot 20 located well within the entrance of the chamber is provided at its top end with a hopper 24 the top end of which extends across a region beneath the path of travel of the bulb trays and receives the broken bulb parts. A vertical wall 21 common to both the shoot 20 and hopper 24 has an opening 22 in its upper end covered by the open end of the horn 23 of a high frequency siren placed against it, whereby the output of the siren is directed into the hopper 24 and the highest intensity of the sound produced is directed upwardly towards the bulbs passing through the chamber 16. The siren is of the kind that produces intense sound over a wide range of frequency. Air is supplied to the siren through a conduit 27, Fig. 4, provided with a pressure regulating valve 28 and a solenoid controlled valve 29 that is normally closed, the solenoid circuit having tray-operated contacts 31-33 and also the contacts of a relay R1 which is operable through a time delay relay T the latter being provided to delay the admission of air to the siren until the latter has had time to attain speed. The switches 31-33 are arranged along the path of travel of the trays through the chamber 16, so that one of the switches is actuated whenever a portion of a tray projects into or occupies the chamber. A relay R2 in parallel with the solenoid circuit of valve 29 closes the circuit of a pulsing relay FP which effects the periodic operation of a relay R3 which, in turn, activates periodically the high speed operating circuit for the siren while trays of articles are within the chamber. On closing a switch S1 connected to a current input terminal X current is fed to one branch of a line 36 and over a line 40 to the back contacts of a relay R2, and thence to the time delay switch T. Current also passes through part of line 36 to an auto-transformer 37, through a rheostat 38 in series with it, and over lines 35, 39 to the siren. The inclusion of the rheostat 38 causes the siren to operate initially at low speeds. After a time delay the relay T closes its contacts, thereby energizing the relay R1 which has inner locking-contacts to hold it closed and outer contacts which close one point in a line common to the operating circuit of relay R2 and the solenoid of valve 29. When relay R2 operates, it opens its back contacts to de-energize the timing relay and closes its front contacts to connect supply lines 40 and 36, to the pulsing relay FP, which operates at pre-set time intervals to energize and deenergize relay R3. Each time relay R3 operates it connects a shunt about rheostat 38 over conductors 35, 39, the contacts of relay R3 and switch S2, thereby causing the siren to operate alternately at low and high speeds in accordance with the adjustment of the rheostat 38 and auto-transformer 37.