LINING OF PIPES

Abstract: Two spray heads (H1, H2) are present for use in lining a pipe (P1), the heads being arranged in line and arranged to apply composition in succession to the inner surface of the pipe.

Description: LINING OF PIPES The invention relates to the lining of pipes, more especially pipes which are to convey potable water, sewage, gas; or the like. The lining is typically a synthetic resin such as an epoxy resin. DT-A-2,448,932, GB-A-2,218,773A and GB-A-2,065,263A disclose pipe-lining apparatus in which an annular body of lining hquid is formed around the periphery of the lining apparatus and confined by the pipe interior. Hence hquid in contact with the interior is deposited thereon as the apparatus advances through the bore ofthe pipe. It is known to pull a lining machine through a pipe to be lined, the machine carrying a spray head and mixer for the lining composition to be sprayed on to the surface to be lined. A lining composition, typically mixed resin and hardener therefor, is pumped to the head which is rotated at such speed that the particles are atomised and apphed to the surface to be lined. In the machines currently available the head is normally in the form of a cylindrical drum which is rotated about its axis and discharges the lining composition through perforations in its cylindrical wall. Such apparatus works well in the case of small diameter pipes but is not sufficiently effective where the diameter is larger and/or it is essential that there are no gaps in the lining. GB-A-865,301 and DE-A-4,400,166 disclose pipe-lining apparatus comprising a carrier adapted to travel through a pipe to be lined, a supply line for feeding lining composition to be sprayed to a spray head located on the carrier, and means for rotating the spray head about the pipe's axis. The present invention provides pipe-lining apparatus as in the above summary, characterised in that the spray head has a generally annular surface whose axis is ahgned with the axis of rotation of the spray head, the surface having an outer peripheral edge portion which is arranged to eject the lining material. Preferably the supply line is arranged to feed a film of lining material in the axial direction over the surface towards the edge portion. Preferably the apparatus comprises two or more such spray heads axially spaced apart and arranged to apply respective superimposed layers of lining material as the carrier travels through the pipe to be lined. Other preferred features are defined in the dependent Claims. The present invention also provides a method in which the spray head has a generally annular surface whose axis is ahgned with the axis of rotation of the spray head, the surface having an outer peripheral edge portion which is arranged to eject the lining material. The invention also provides a spray head for pipe lining apparatus, the spray head being characterised by a generally disc-shaped floor having an upstanding generally cylindrical side wall which is shaped to direct atomised lining composition radially outwardly ofthe wall when rotated about its axis. A spraying assembly may comprise at least two spray heads, each comprising a generally disc shaped floor having an upstanding side wall, which is shaped to direct atomised lining composition outwardly of the wall. The side wall preferably has an outwardly flared upper portion. Additionally or alternatively, holes are present in the side wall. The head may for example range from say 50mm to about 350mm in diameter. In order that the invention may be well understood it will now be described by way of example only with reference to the accompanying diagrammatic drawings in which Figure 1 is a general view of one embodiment of apparatus ofthe invention; Figure 2A is an end elevation of an assembly of two heads for use in the apparatus of Figure 1 ; Figure 2B is a partial longitudinal section taken on lines IIB-IIB of Figure 2A; Figures 3 to 5 are longitudinal sections of other spray head assemblies useful in the apparatus and method ofthe invention; and Figure 6 is a diagrammatic plan view ofthe apparatus of Figure 1. The same reference numerals are used where possible in describing the different embodiments, with the addition of a suffix. The lining machine shown in Figure 1 comprises the usual air compressor and generator unit 1, pump unit 2 and reservoirs 3, 4 of unhardened resin and hardener therefor. Hose supply lines 3A, 4A from the reservoirs are coiled about a winch reel 5 and extend forward to a carrier 6 dimensioned to pass through the pipe P to be lined. The carrier 6 comprises a trolley 7 which may have wheels or skids by which it passes through the pipe P and carries an inline static mixer 8 into which the hose supply pipelines feed. A motor 9 is present to rotate a spray head assembly H made up of a number of spray heads HI, H2, shown in Figure 1. The heads may be made of aluminium or the like. As shown in Figure 2, each head is a disc 10, having an upstanding sidewall rim 11. A supply line 12 from the mixer 8 extends axially of the heads, and has side holes 13 adjacent the floor of each head. The inside of the upper portion 14 of the rim 11 is outwardly inclined as shown, and shoulders 15 are present to receive bolts 16 by which one head may be secured to the next (as shown in Figure 2B, the shoulders 15 are only present in the head HI). When the heads are rotated (at up to say 10,000 RPM), mixed resin composition emerging from the holes 13 is directed (as indicated by path 20) along the floor of the respective heads, and up the rim 11 to be atomised and thrown out as a spray 21 from the outer peripheral edge portion ofthe rim on to the surface of the pipe P to be lined. Because there are two heads in line, two layers of lining are apphed in succession, so guaranteeing that the lining is complete, which is particularly important when the material to be conveyed through the pipe is potable water. In the embodiment of Figure 2, the two heads HI and H2 have generally dished floors. As shown in Figure 3, the floor 10A of the head HI may be curved, to influence the passage of composition to be lined. As shown in Figure 4, three heads HI, H2, H3, may be present with shoulders 15 being present in heads HI and H2. As shown in Figure 5 the rim I IA may have holes 17 so that the atomised particles can emerge from the sides ofthe head instead of or additional to that passed out along the portion 14 ofthe rim. The dimensions of the heads and/or the rate of rotation and viscosity of the lining composition may be adjusted relative to each other to control the rate of apphcation of the lining, in known manner. The pipe to be lined is built up of lengths of conduit joined together and may be made of concrete, plastics, metal; or the like. Referring to Figure 6, the carrier 6 is shown connected via resin and hardener supply hoses 3A and 4A and an air hose 19 to a trailer unit 18 on which the generator/compressor unit 1, resin and hardener tanks 3 and 4, hose reel 5 and associated king pump 2 and other equipment are mounted. The air line 19 supphes compressed air to drive pneumatic motor 9 on the carrier and is connected to an air supply line 20. As shown, the resin, hardener and air supply hoses lead to the reel 5 and can be fed out under the control of a gearbox and motor 21 , clutch 22 and further gearbox 23 to the carrier 6 as the latter is drawn through the pipe by a ferret winch 24 (connected to a line, not shown, attached to the carrier). The apparatus is controlled from a control panel 27. The temperature (and hence the viscosity of the resin and hardener) can be controlled by a fan heater 25 and a fan cooler 26. The invention is not limited to the embodiments shown. There may be more than three heads: one may be offset from the other (or others); the resin need not be epoxy.

Claims: CLAIMS 1. Pipe lining apparatus comprising a carrier (6) adapted to travel through a pipe (P) to be lined, a lining composition supply line (3a,4a) for feeding composition to be sprayed to a spray head (HI ,H2,H3) located on the carrier, and means (9) for rotating the spray head about the pipe axis, characterised in that the spray head (H1,H2,H3) has a generaUy annular surface whose axis is ahgned with the axis of rotation ofthe spray head, said surface having an outer peripheral edge portion (14) which is arranged to eject the lining material. 2. Apparatus as claimed in Claim 1 , wherein the supply line (3a,4a) is arranged to feed a film of lining material in the axial direction over the surface towards the edge portion (14). 3. Apparatus as claimed in Claim 1 or Claim 2, wherein the edge portion (14) includes an edge arranged to eject atomised lining material. 4. Apparatus as claimed in any preceding Claim, comprising two or more such spray heads (H1,H2,H3) axiaUy offset and arranged to apply respective superimposed layers of lining material as the carrier travels (6) through the pipe (P) to be lined. 5. Apparatus as claimed in Claim 4, wherein one spray head (HI ) has ledge means (15) within its mouth on which another spray head (H2) is supported. 6. A method of lining a pipe, comprising moving a carrier (6) having a spray head (H1,H2) longitudinaUy through the pipe (P) whilst rotating the spray head about a longitudinal axis and feeding lining composition to the spray head, thereby spraying the lining composition onto the interior surface of the pipe, characterised in that the spray head (H1,H2) has a generaUy annular surface whose axis is ahgned with the axis of rotation of the spray head, the surface having an peripheral edge portion (14) which is arranged to eject the lining material. 7. A spray head (H1,H2,H3) for pipe lining apparatus, characterised by a generaUy disc-shaped floor (10) having an upstanding generaUy cylindrical side waU (11) which is shaped to direct atomised lining composition radiaUy outwardly ofthe waU when rotated about its axis. 8. A spray head (H1,H2,H3) as claimed in Claim 1, wherein shoulders (15) or a ledge are formed on the inside surface ofthe upstanding waU and are arranged to receive the floor of an adjacent spray head.

Inventors: TALBOT SAMUEL LESLIE, TALBOT, SAMUEL, LESLIE
Applicants: FOSROC INTERNATIONAL LTD, TALBOT SAMUEL LESLIE, FOSROC INTERNATIONAL LIMITED, TALBOT, SAMUEL, LESLIE
Application year: 1996
Main classification: F16L55
IPC codes: B05B13, F16L55