GB749811A - Improvements in fumigating devices - Google Patents

Abstract

749,811. Fumigating devices; insecticidal compositions. MURPHY CHEMICAL CO., Ltd., and WALPOLE, J. L. Sept. 13, 1951 [Sept. 19, 1950], No. 23025/50. Class 81(1). A fumigating device comprises, in one modi. fication, a container of paper, fabric or other porous material, impregnated with pot. assium nitrate for ex. ample, to render it partially self-combustible, completely en. closing a mixture of a " partially self-combustible composition and a vaporisable heat-controlling substance, and a removable outer envelope of moisture resistant flexible material. Alternatively the outer envelope may be dispensed with if the " partially self-combustible " material forming the container is also a moisture resistant material. " Partially self-combustible " denotes that the material or composition concerned contains molecular or added oxygen in amount sufficient for it to burn slowly in ambient air but insufficient to burn in the absence of air. Figs. 1 and 2 respectively show the inner container and the outer moisture resistant envelope. The latter may be made of wax-or bitumen-impregnated paper or fabric, cellulose derivatives, synthetic resins, metal foil or a metal foil-paper composite sheet. The inner container may contain a length of ignition fuze 6 embedded therein, and the top may be folded and crimped at 9 and the flap 8 provided with a stapled ignition fuze 10. Alternatively a container and lid may be made of moisture resistant partially selfcombustible material such as a synthetic resin or cellulose derivative. The partially selfcombustible composition comprises a mixture of a combustible material for example, a cellulosic material such as saw dust or wood flour or a cellulose derivative such as the acetate and an oxygen yielding substance such as sodium, potassium or barium nitrates or potassium or barium chlorate. An absorbent material such as china clay or diatomaceous earth may be incorporated. The composition must be such that the heat generated on combustion will be sufficient to vaporize the pesticide but insufficient to decompose it.. Pesticides exemplified are insectidal polyphosphate or thiophosphate esters such as tetraethyl pyrophosphate, hexa- . ethyl tetraphosphate and diethyl p-nitrophenyl thiophosphate, or nicotine, pyrethrum, organo mercury compounds such as mercury phenyl acetate or mercury salicylate, or bis- (bis dimethylamino-phosphorous) anhydride. Two or more different pesticides may be employed together, or two different pesticides may be incorporated in separate porous containers enclosed in a common moisture-resistant envelope.