| 摘要 |
<p>1504051 After treatment of concrete coatings BREDERO PRICE BV 9 April 1975 [5 Dec 1974] 14484/75 Heading B2E [Also in Division B5] A groove is cut in an uncured concrete coating on an arcuate surface of an object, by a water jet directed tangentially to the surface as the surface and jet are relatively rotated. As shown, a preformed pipe 10 (Figure 2) is rotated and moved longitudinally while coated with concrete applied by a brush 32 and underlayed by asphaltic mastic, butyl rubber or polyethylene. The concrete includes iron ore aggregate and sprayed water, and embeds a plurality of reinforcing cages (see Figure 1, not reproduced) and chicken wire. An impervious plastics sheet; or chicken wire, can be wrapped about the concrete as it is layed, and then removed after partial curing (Specification 1504052) for cutting. Preferably immediately after coating, the pipe is supported on, and rotated by, rollers 42 (Figure 4) during cutting by a plurality of nozzles 44 adjusted so as to direct water jets 60, fed from a common manifold 48, tangentially to the preformed pipe.</p> |
