GB2304167A - Lining insides of pipes - Google Patents

Abstract

Two spray heads H1, H2 are present for use in lining a pipe P, the heads H1, H2 being arranged in line and arranged to apply composition, from the same supply line, in succession to the inner surface of the pipe P. The heads H1, H2 are supported by a carrier 6 which travels inside the pipe. Hose supply lines 3A, 4A feed into an inline static mixer 8 from reservoirs 3, 4 of unhardened resin and a hardener therefor. Use of two heads H1, H2 ensure application of two layers of lining in succession thereby guaranteeing that lining is complete. Each head comprises a floor 10 and with a side wall 11 shaped to direct atomised lining composition outwardly of wall 11. A plurality of heads may be connected in series.

Description

Agent's ref: P01286GB 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 plastic such as an epoxy.

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 applied to the surface to be lined. In the machines currently available the head is generally can or cylinder shaped.

Such apparatus works well in the case of small diameter pipes but is not sufficiently effective where the diameter is larger.

It is one object of this invention to provide apparatus to satisfy that need.

According to the invention in a first aspect there is provided apparatus for the purpose specified 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 characterised in that at least two spray heads are present. the heads being arranged in line and each being fed from the same supply line. and arranged in use to apply composition in succession to the surface.

For the purposes of this invention the heads should be generally disc shaped. and arranged generally coaxially.

In another aspect the invention provides a method of lining a pipe, the method comprising spraying at least two layers of lining composition on to the interior surface of the pipe by passing through the pipe to be lined apparatus carrying a corresponding number of spray heads, each spraying the lining composition.

Preferably in the method the spray heads are arranged in line. Preferably the heads are each supplied from a common supply line.

In yet another aspect the invention provides 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 and/or holes are present in the side wall. In yet another aspect the invention provides a sprayhead which is as defined and which has shoulders or a ledge on the inside surface of the upstanding wall to receive the floor of the adjacent head.

The head may range from say 50mm to about 350mum 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 of the invention; Figure 2 is a partial longitudinal section drawn to an enlarged scale of one spray head; Figures 3 to 5 are views as Figure 2 of other embodiments of spray head.

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 H1. H2, shown in Figure 1. The heads may be made of aluminium or the like.

As shown in Figure 2. each head is a dished type 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 upper portion 14'of the rim 11 is outwardly flared 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 2. the shoulders 15 are only present in the head H1). When the heads are rotated (at up to say 10.000 RPM), mixed resin composition emerging from the holes 13 is directed along the floor of the respective heads. and up the rim 11 to be atomised and thrown out on to the surface of the pipe P to be lined. Because there are two heads in line. two layers of lining are applied in succession, so guaranteeing that the lining is complete. Because the apparatus applies an even coverage of lining onto the inside surface of the pipe there is no risk that bare metal is left exposed so that corrosion cells can be set up.

In the embodiment of Figure 2, the two heads H 1 and H2 have generally dished floors. As shown in Figure 3, the floor 10A of the head H1 may be curved, to influence the passage of composition to be lined. As shown in Figure 4, three heads H1, H2, H3, may be present shoulders 15 being present in heads H1 and H2. As shown in Figure 5 the rim 11A may have holes 17 so that the atomised particles can emerge from the sides of the head instead of or additional to that passed out along the portion 14 of the rim.

The dimensions of the heads and/or the rate of rotation and viscosity of the lining composition may be adjusted relative and to take account of the diameter of the pipe being lined.

The pipe to be lined is built up of lengths of conduit joined together and may be made of a variety of materials including concrete, asbestos, plastics.

metal, e.g. iron; or the like.

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. In the embodiment shown the heads face outwardly in the same direction but they can face in opposite directions.

Claims (7)

1. Apparatus for use in lining a pipe. the 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 characterised in that at least two spray heads are present.

the heads being arranged in line and each being fed from the same supply line. and arranged in use to apply composition in succession to the surface.

2. Apparatus according to Claim 1 wherein the heads are generally disc shaped. and arranged generally coaxially.

3. A method of lining a pipe, the method comprising spraying at least two layers of lining composition on to the interior surface of the pipe by passing through the pipe to be lined apparatus carrying a corresponding number of spray heads. each spraying the lining compositions.

4. A method according to Claim 3, wherein the spray heads are arranged in line.

5. A method according to Claim 3 or 4, wherein the heads are each supplied from a common supply line.

6. A head for use with pipe lining apparatus. comprising 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.

7. A sprayhead according to Claim 6 having shoulders or a ledge on the inside surface of the upstanding wall to receive the floor of the adjacent head.