Patent GB-860582-A (GB)
Title: Cleaning or degreasing apparatus and method
Inventor: KEARNEY THOMAS JAMES
IPC: B08B3/12
Filed: 1957-06-07
Abstract: 860,582. Degreasing metal objects. DETREX CHEMICAL INDUSTRIES Inc. June 7, 1957, No. 18292/57. Class 82(2) [Also in Group XL(b)] A method of cleaning or degreasing metal objects comprises transporting the objects in a carrier to a spraying zone where they are sprayed with liquid chlorinated hydrocarbon, removing the objects from this zone, and then immersing the objects in a bath of the solvent where they are subjected to ultrasonic radiation generated piezoelectrically within the bath, the means of generation being out of direct mechanical contact of the objects. As shown, an apparatus suitable for the process comprises a housing 30 which is completely closed except for opening 31 where objects to be cleaned are loaded or unloaded from carriers 148. Inside are contained three wells 33, 34, and 35 and two dams 36 and 37. Well 33 contains solvent which is continuously boiled by a heating coil 39, 40, the resulting vapour being condensed by cooling jacket 41, collected in fan 44 and carried by line 45 to a gravity water separator 46 whence solvent passes by line 49 to condensate receiver 50 (Fig. 5), and by pipe 51 to storage tank 52, flow through line 51 being controlled by valve 53, liquid from receiver 50 is pumped along pipes 54 and 59 to a series of spray nozzles 60 positioned to spray liquid over the objects as they emerge on carriers 148 from ultrasonic well 35. Well 35 may be emptied by means of suction pipe 61 and pump 67, which passes the liquid into lines 62, 63, and 66. The outlet of this pump leads to storage tank 52 through lines 71, 72, 74, and 76. Well 34 may be emptied through suction pipe 77 and line 78, which then joins line 63. The storage tank 52 is also connected near the bottom with lines 63 and 66 by means of lines 80, 81, and 83, and is controlled by valve 82. The wells may thereby be replenished with liquid through lines 84, 85, 87, 89, 90, 92, 93, and 95. Well 35 contains heating coil 96 which maintains the liquid at the correct temperature (110-140‹F. for trichlorethylene; 140-170‹F for perchlorethylene; 57-78‹F for methylene chloride). Excess liquid flows over dam 37 into the well 34, and overflow pipe 97 permits solvent to overflow from well 34 into well 33. Well 34 is provided with spray nozzles 98, mounted on headers 99, and fed with solvent from well 34 by way of pipes 77, 102 and 103, pump 104, pipe 107, strainer 109 or 114 which are worked alternately to permit cleaning of each in turn, and either lines 110 and 112 or lines 116 and 118. Carriers 148 are hung from an endless double chain conveyer and pass continuously or with intermittent stops in wells 34 and 35 over sprocket wheels 121-137 in turn, being driven by motor 146 (Fig. 4). The objects are thereby carried in turn into well 34 where they are sprayed with solvent from nozzles 98, and then into well 35 where they are immersed in solvent and subjected to ultrasonic radiation, suitably in the range 10 Kc/s-1 Mc/s produced by transducers 160 which are energized by' oscillator unit 200. The transducers are suitably mounted so that the radiation is directed downwards on to the objects which pass below the transducer mounting 171 in carrier 148 out of mechanical contact with the transducers. The transducers which are suitably fabricated of barium titanate are of the shape of an arcuate longitudinal section of a cylinder arranged concave side downwards (see Group XL (b)), the convex side being continuously sprayed with liquid through nozzles 201 to prevent accretions of deposits causing a short circuit. Nozzles 201 are supplied with liquid pumped from well 35 by pump 205 and filtered through filter 209 (Fig. 5). After leaving the ultrasonic well 35 the carrier passes upwards, and the objects are sprayed by nozzles 60, and then subjected to a final vapour rinse before passing above cooling jacket 41 and eventually to opening 31 where the cleaned objects are removed. Specifications 860,580, 860,581 and 860,583 are referred to.