GB297782A - Improved process of and apparatus for producing foam - Google Patents

Abstract

297,782. Schnabel, R., Jacobsen, J., and Excelsior Feuerloschgerate Akt.- Ges. May 24, 1927. Freely-flowing matter mixed in conduits.-In the method of generating foam by forcing a finelydivided gaseous 'pressure medium into a foam generating solution, both the gas and solution are subdivided and intermingled by passage under pressure, preferably together, through a mixing body or bodies such as a body or plate of ceramic material, stacked sieves or plates of asbestos, fibrous materials or textiles, sponge, or gravel or like filters. An alternative mixing body comprises a chamber into which the constituents are separately forced in whirling motion with their paths intersecting. The gaseous medium may be enriched by passage through a halogen or halogen compound before application to the foam generator, and may be put under pressure by means of a hand pump, air compressor &c. Anti-freezing or extinguishing compounds may be added to the foam generator. In the apparatus shown in Fig. 1, the porous septum is in the form of a hollow cylinder 32 within a casing 31 having a connection h for the foam pipe. Gas under pressure is supplied to the septum 32 by a pipe e from which a branch 30 leads to the container a to force the foam generator to the septum by way of a pipe 33. Dry foam generator might be housed in the cylinder 32, and the container a be charged with water. In a modification, Fig. 2, the mixing body 11 is arranged near the bottom of the container 6 for foam generator. Pressure gas is supplied to the body 11 by a pipe 16 controlled' by cock 18, and by a branch 17 to the space above the foam generator, so that the latter is forced through a sieve 9 and into the body 11 by way of an entrance 10 controllable in size by a screw plug 7. The foam formed passes by a tube 19 and a gravel filter 20 to the foam pipes 21. The mixing body 11, Fig. 4, comprises an annular chamber 23 which the solution enters by way of tangential nozzles 22, the stream of solution whirling round the chamber 23 and intersecing its path of entry before escaping through small outlets 24 to the pipe 19. The pressure gas pipe 16 also enters the chamber 23 tangentially in a direction to intersect the path of the solution. A test cock 14 is provided in the container 6. In a modification of this form of mixing body, the pressure gas enters the chamber 23 by way of a perforated annular pipe, and the whirling stream of solution is given a sudden change of direction in escaping from the chamber, the inner surface of which is of irregular outline.