US3031365A

US3031365A - Process for providing asbestos-cement pipes with sockets

Info

Publication number: US3031365A
Application number: US843383A
Authority: US
Inventors: Marchioli Giorgio; Gremigni Giuseppe
Original assignee: ITALTUBI SOC PER AZ RI Soc
Current assignee: ITALTUBI SOC PER AZ RI Soc; Italtubi Soc Per Az Riunite G I M F A-Italtubi Soc
Priority date: 1959-04-03
Filing date: 1959-09-30
Publication date: 1962-04-24
Anticipated expiration: 1979-04-24

Description

April 24, 1962 G. MARCHIOLI ETAL PROCESS FOR PROVIDING ASBESTOSCEMENT PIPES WITH SOCKETS 4 Sheets-Sheet 1 Filed Sept. 50, 1959 p i 1962 G. MARCHIOLI ETAL 3,031,365 PROCESS FOR PROVIDING ASBESTOS-CEMENT PIPES WITH SOCKETS Filed Sept. 30, 1959 4 Sheets-Sheet 2 April 24, 1962 G. MARCHIOLI ETAL PROCESS FOR PROVIDING ASBESTOS-CEMENT PIPES WITH SOCKETS 4 Sheets-Sheet 3 Filed Sept. 30, 1959 A ril 24, 1962 G. MARCHIOLI ETAL 3,031,365

PROCESS FOR PROVIDING ASBESTOS-CEMENT PIPES WITH SOCKETS Filed Sept. 50, 1959 4 Sheets-Sheet 4 United States atent PROCESS FOR PROVIDING ASBESTOS-CEMENT PIPES WITH SOCKETS Giorgio Marchioli and Giuseppe Gremigni, Milan, Italy;

Various ways have been previously proposed for applying sockets to asbestos-cement pipes. For example, it is known to apply a preformed asbestos-cement socket in the fresh state to a pipe which is also in the fresh state, in order to obtain, after hardening of the cement, an adhesion between the socket and pipe.

With the above known method however it is necessary that deformation of either the fresh pipe or the fresh socket be confined within very narrow limits, because the material which is moist, but which contains a comparatively small proportion of water and is strongly rammed or compressed, can not stand considerable deformations Without being spoiled. Hence, it has been further proposed not to deform the external surface of the two parts to be joined, but to limit the deformation to mere variation of volume as caused by the compression of one element upon the other one.

As distinguished from the above, the process embodying the present invention initially modifies the material forming the socket and the pipe end in such a manner as to render it capable of standing even considerable deformations and, therefore, there is no need to observe the previously imposed limitations on deformation of the material, with the further advantage that the union of the material constituting the socket with that constituting the pipe is realized in a much more complete and perfect manner.

According to the present invention the end of the previously shaped green uncured asbestos-cement pipe is wetted to such extent as to soften it by absorption of water; the material forming wholly or partly the socket, is applied to the softened pipe end; and the two parts are joined together in a stable manner by application of radial compression against one another while excess water is simultaneously removed therefrom.

More particularly the above method is preferably carried out by wetting one end of the fresh pipe introducing thereinto part of a resilient, radially expansible inflatable core, applying to the remaining part of the core the material destined to form the socket, introducing the whole into a foraminous cover within a permeable mould and inflating the core to obtain radial compression and elimination of excess water.

The above, and other features and advantages of the invention, will be apparent in the following detailed description of an illustrative embodiment thereof which is to be read in connection with the accompanying drawings, wherein:

FIGS. 1 to 7 are diagrammatic views illustrating successive steps in the process embodying this invention;

FIG. 8 is a transverse sectional view of an apparatus suitable for use in practicing the process;

FIG. 9 is a longitudinal sectional view of the apparatus of FIG. 8; and

FIG. is a view illustrating an alternative procedure for providing the material of which the socket is formed at one end of a pipe.

Referring to the drawings in detail, and initially to FIG. 1, there is shown a fresh pipe 1, that is, a previously shaped and compressed green uncured pipe, from which all excess water has already been removed; and which is mounted on a rigid mandrel 2. The end portion of the pipe 1 is first chamfered by removal of material or by deformation as indicated at 3 in FIG. 2; then the pipe is displaced axially with respect to the mandrel in such a way as to make the chamfered end project beyond the mandrel and a water jet '4 is directed thereunto as indicated diagrammatically in FIG. 3. The chamfered end 3 then is flared, for instance by using a tool of round shape of the kind indicated at 5 in FIG. 4.

Referring now to FIG. 5, there is shown an inflatable core 6, carried by any suitable support 7, and comprising two coaxial cylindrical parts of different diameters. A ring 8 of material equal to that of which the pipe 1 is made, is applied or shaped on the part of core 6 of larger diameter, said ring having a border 9 which is chamfered externally. The ring 8 placed upon the core 6 is wetted by a water jet 10 in such a way that it too becomes soaked with water and softened.

Then the support 7 and the mandrel 2 are moved relatively toward each other so that the narrower part of the core 6 enters into the pipe 1 and the chamfered end or border 9 of the ring 8 penetrates into and comes into surface contact with the flared end 3 of the pipe 1, as shown in FIG. 6.

Around the assembly as above described, there are closed the parts constituting a permeable mould 11 which defines the shape that the outside of the finished pipe is to assume at the socket end.

The core 6 then is inflated to exert a radially outward pressure upon the inner wall surface of the end of the pipe 1 and of the ring 8 while ejecting the excess water contained therein through the permeable wall of the mould 11, whereby the two

parts

3 and 8 become joined together to form a single and homogeneous piece. The finished pipe is then extracted from the open mould, while pulling out the deflated core, as indicated in FIG. 7.

In a practical apparatus (FIGS. 8 and 9) for practicing the above process, the core 6 made for instance of rubber is mounted on a rigid piece 12 and is blocked, at its ends,

by two

terminal rings

13 and 14. The piece 12 is hollow axially, as at 15, and is provided with radial channels 16 so that, by introducing air or water under pressure through the connection 17 at one end, it is possible to inflate the core, which thereby can expand radially but not axially.

When the pipe 1 and ring 8 are joined in the apparatus of FIGS. 8 and 9, a thin metal wire gauze or a thin perforated metal sheet 21 or other water permeable sheet material is placed thereover prior to closing the parts 11 of the mould, and the latter are perforated with holes 18 for discharging of the excess water. The parts 11 of the mould are supported for radial displacement in a ring 19 by means of hydraulic jacks 20 or any other convenient means.

The process according to the invention is susceptible of variations from the specific embodiment hereinbefore described. For instance the ring 8 may be applied wholly externally with respect to the pipe 1 and, in that case, the flare at the end 3 of the pipe 1 is made less sharp or if desired may even be dispensed with.

The material for obtaining the socket may even not constitute a ring separate from the pipe 1. For instance thanks to the softened state of the wetted pipe 1, it is possible to make an axial cut at its end 3 so that, on introducing the core 6 into the end 3 of the pipe, the cut widens to form the recess 22 shown in FIG. 10. Then, in said recess there is applied a piece 23- of equal dimensions made of the same material and the whole is shaped in the mould in the same manner as above described. Of course, the end 3 of pipe 1 may be provided with more than one of the cuts and the corresponding pieces 23 to define the material for forming the socket end.

Although an illustrative embodiment of the invention and specific modifications thereof have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to that precise embodiment or the modifications thereof,

.and that various other changes and further modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention except as defined in the appended claim.

We claim:

A process for forming a bell-end socket on an asbestoscement pipe comprising wetting the end of a green uncured asbestos-cement pipe so as to soften the same, inserting a resilient, inflatable core member into said softened end of the pipe, placing additional socket forming asbestos-cement material on said core member, surrounding said end of the pipe and said additional socket forming material with a foraminous cover, inserting said end of the pipe and said additional socket forming material surrounded by the foraminous cover in a perforated mould, and inflating said core member so that the latter expands radially and exerts a uniform radial compression of said end of the pipe and said additional socket forming material against said mould While the excess moisture is simultaneously expressed through said foraminous cover and perforated mould.

References Cited in the file of this patent UNITED STATES PATENTS 693,571 Shaw Feb. 18, 1902 1,285,546 Young Nov. 19, 1918 2,383,582 Barbehenn Aug. 28, 1945 2,528,155 Magnani Oct. 31, 1950 2,962,408 Fourmanoit Nov. 29, 1960