GB794195A - Improvements relating to methods and apparatus for forming underground concrete pipes in situ - Google Patents

Abstract

794,195. Casting pipes. curbs &c. in situ. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Dec. 28. 1955 [Dec. 30, 1954], No. 37715/54. Class 20(2) An underground concrete pipe is cast in a tunnel formed by a mole plough 10, of saturated concrete supplied through a passage 15 in the plough coulter 11 over a hollow cone 12 towed by the plough and having perforations 31 through which suction removes surplus liquid from the concrete. The outside of the pipe is moulded by a shroud 13 the bottom of which may be cut away so that the shroud tapers to an arcuate cover only over the rear of the cone, or the shroud may be dispensed with. Concrete may be supplied direct by a vibrated hopper or by a concrete pump to the passage 15. but as shown in Fig. 1 is supplied from a tank 17 under pressure from an air compressor 22. The tank 17 contains a rotary agitator 18. Suction to the core 12 and perforations 31 is applied through a passage 25 by a pump 28 connected to a tank 27 to which is also connected a pump 29 for slurry which is returned to the tank 17. An inclined plate 32 secured to the rear of the coulter closes the slot formed by the coulter. The cone 12 may be mounted in a socket in the plough in which is a vibrator to vibrate the cone longitudinally. Different arrangements of perforations 31 are described. The Provisional Specification refers to the construction of curbs, open conduits, roads, parapets and walls by a similar method. To form a curb wet concrete is laid by a moving mould in a furrow formed previously or by a plough on the mould and suction is applied to the concrete by means of a jacket at the rear end of the mould. Specification 793,942 is referred to.