GB2267049A

GB2267049A - "Apparatus for and method of Insulating Pipes"

Info

Publication number: GB2267049A
Application number: GB9300391A
Authority: GB
Inventors: Clive Robin Tovey
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-02-01
Filing date: 1993-01-11
Publication date: 1993-11-24
Anticipated expiration: 2013-01-11
Also published as: GB2267049B; GB9300391D0

Abstract

A dispenser for liquid foam which rapidly expands and hardens on exposure to air has a shaped head (21, 27, 28) to fit laterally over a pipe (P, P<1>) and to be moved along it. The foam issues into this head and is guided by it into an insulating jacket around the pipe. There are means (216) for locating the head correctly with respect to the pipe and means (31) for allowing the head to negotiate pipe joints and supports. The head may be interchangeable with others to cater for different pipe sizes, and each head may swivel with respect to the rest of the dispenser for ease of application. The foam feed may be automated to suit the pipe size and speed of traverse. <IMAGE>

Description

'Apparatus for and Method of Insulating Pines" This invention relates to apparatus for and a method of insulating pipes. Although the Specification will refer, for convenience, solely to pipe insulation, which is seen as the main use of the invention, it should be understood that it could also be applied to coating other elongate elements such as cables, to give them extra insulation, and railings, to make them bulkier and softer and therefore safer.

The most common form of modern pipe insulation uses pre-formed tubes of soft foamed plastics material, each split down a seam which enables it to be spread and eased laterally over a pipe. With a straight run, the seam closes up again and the tube can be firmly fixed by taping or glueing. Such tubes are quite easily cut to required lengths.

However, this form of insulation does have several drawbacks.It can be difficult and time consuming to apply, but the real problems come at supports and corners. The seam does not then close up completely, and indeed can gape quite significantly. Also, over the course of time, some types of insulation tube shrink, and protection at the seams and joints is lost.

It is the aim of this invention to avoid such problems and to enable insulation to be applied quickly, directly and comprehensively whatever the size or configuration of the pipework.

According to one aspect of the present invention there is provided apparatus for insulating pipes comprising a dispenser of liquid but expandible and rapidly setting foam, the delivery end of which has a head for embracing a pipe and for guiding dispensed foam around the pipe, and means for locating the head with respect to the pipe while permitting movement of the head along the pipe.

In the most usual form, the head will be generally Cshaped, to be fitted over the pipe laterally. The dispensed foam will then emerge substantially centrally into the convexity of the C.

Conveniently, the head will be rotatable with respect to the rest of the dispenser about the mouth of the foam conduit. Pipes are often tucked away into corners, and this allows the operator to keep the head in place over the pipe while swivelling the rest of the dispenser clear of the adjacent wall, floor or ceiling.

Preferably, the head will be removable from the rest of the dispenser and will be one of a set of exchangeable heads adapted for different sized pipes.

The locating means may simply comprise an element shaped to engage a portion of the pipe just ahead of the foam as it is dispensed. The operator will merely have to keep this pressed against the pipe as he moves the dispenser along it. This element may be a fixed part of the head and slide along the pipe,- or it may be rotatable and roll along.

Preferably, however, the element is composite, having a fixed portion to slide along the pipe and a toothed rotatable portion which normally also slides along the pipe bt means of a pair of teeth. But, when an obstruction such as a pipe joint or supporting strap is reached, the leading tooth of the sliding pair engages that obstruction and acts as a trip to lift the fixed portion over the obstruction, the rotatable portion turning with respect to the fixed portion and the leading tooth becoming the trailing one of another sliding pair. Conveniently, the toothed rotatable portion is a pointed star-like wheel. It may be removable from the fixed portion, to enable easy cleaning.

In more elaborate versions, there may be means for sensing the relationship of the head to the pipe and for permitting foam dispensing only when the head is appropriately located with respect to the pipe. Also, there may be means for detecting progress of the head along the pipe and for governing the delivery of foam in accordance with such progress. In other words, it need not be left to the operator to judge how much foam to dispense. This may be augmented~-by means, settable by the operator, to govern the delivery of foam in accordance with the size of the pipe.

According to another aspect of the present invention, there is provided a method of insulating pipes wherein foam is dispensed using apparatus as defined above.

For a better understanding of the invention, some embodiments will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an axial section of a foam dispenser, figure 2 is a cross section on the line II-II of Figure Figure 3 is a section of an alternative head fittable to the dispenser of Figure 1, Figure 4 is a section of another head fittable to the dispenser of Figure 1, Figure 5 is a sectional detail of a modification to the heads, Figure 6 is a perspective view of that modification, and Figure 7 is a longitudinal section of an alternative handle for the dispenser In Figure 1, a canister 1 of liquid foam is screwed laterally into a barrel 2 of a dispenser. The liquid will expand and rapidly harden on exposure to air.A ball valve 3 at the mouth of the canister is automatically opened by this action, admitting the liquid via port 4 into a central passage 5 within the barrel 2. A valve member 6 has its stem 7 extending co-axially along this passage, its head 8 normally closing the flared mouth at the right hand end as seen in Figure 1. Towards the other, rear end, the stem 7 passes through an 0-ring seal 9 into an enlarged chamber containing a coil spring 10 and closed by a bush 11 which serves as a guide for an enlarged rear end portion 12 of the stem. A washer 13 normally rests against the inner end of the bush 11 and against a shoulder of the portion 12 under the influence of the spring 10.

Beyond the bush 11, the enlarged end portion 12 can be acted upon by a trigger 14 pivoted at 15 to an extension of the barrel 2 and limited in its clockwise motion by a stop 1a. A cam 17 captive to a stud 18 on the other side of the barrel acts as a stop to anti-clockwise pivoting of the trigger 14, and by rotating the cam 17 the extent of the trigger action can be adjusted.

It will be seen that when the dispenser is fitted to the canister 1, although foam fills the passage 5, initially it cannot escape. But pressing the lower end of the trigger 14 urges the valve member 6 to the right against the action of the spring 10. The head 8 therefore is lifted clear of the mouth of the passage 5 and foam can escape, being guided and spread by the underside contour of the head 8.

Around the delivery end of the passage 5, the barrel 2 has a reduced diameter portion 19, with an annular groove to receive a resilient ring 20. Different foam distributor heads can be fitted over this portion 19, with a snap-on engagement with the ring 20. Each head so fitted can swivel about the axis of the barrel.

The head 21 of Figures 1 and 2 has a cylindrical base 22 with an inner annular groove 23 for engagement by the ring 20. This base 22 develops into a generally C-shaped hood 24 one end of which has an inwardly projecting flange 25 whose free edge is generally U-shaped. But at the centre of the web of the U, there is a saddle 26 projecting further into the concavity. It has a concave curved surface designed to bear against a pipe P and thereby locate the head 21 in relation to that pipe. The centre of curvature of the saddle 26 is also the approximate centre of curvature of the Cshaped hood 24, although, as illustrated, that may not be truly part-cylindrical.

In use, the hood 24 is placed laterally over a pipe P as shown and the trigger 14 pressed. Simultaneously, the operator will move the dispenser along the pipe P, with the flange 25 leading. The saddle 26 is kept pressed against the pipe. The foam issuing past the head 8 centrally into the 'C' is directed around the inside of the hood 24 and thus embraces the pipe P. Because of its expansive qualities, it will join up at the back, and close in on the pipe. The thickness of the foam cladding will be determined by the speed with which the dispenser is moved along the pipe and the extent to which the trigger 14 is pressed in, which of course is set by the cam 17.

Should a larger pipe pl require insulation, the head 21 is removed and replaced by a similar but larger one 27, as shown in Figure 3.

Some pipes are tucked into corners where it would be difficult5)br even impossible to use a head such as those shown in Figures 1 and 3. In that case, an asymmetric head 28, lacking one limb of the C, may be used, as shown in Figure 4.

Instead of a fixed saddle 26, there could be one or more waisted rollers to follow the-pipe. The dimension of the saddle or other guide means lengthwise of the pipe will preferably be quite short, of the order of 1 cm, so that the device will accommodate to curves without becoming signifi catty offset.

Pipes have to be supported at intervals, and they also have joints. These form obstructions to the saddle 26. While the operator can simply shift the dispenser slightly away from the pipe to cope with this, there is apt to be a delay in which too much foam is dispensed. Therefore, the arrangement of Figures 5 and 6 may be adopted enabling the saddle automatically to step over such an obstruction.

In the leading face of the saddle 26 there is a recess 29 spanned by a shaft 30 carrying a rotatable four-pointed star wheel 31. The position of the shaft 30 and the size of the wheel 31 are such that, as the dispenser is run along a pipe, two fingers have their tips flush with the convex contour of the saddle 26, and so they slide along the pipe.

The tips of the leading one of those fingers and of another one, diametrically opposite the trailing sliding finger, are slightly forward of the flange 25. It will be seen from Figure 5 that, when an obstruction 32 is met, the leading sliding finger is arrested by the shoulder presented to it and this will cause the wheel 31 to turn. This will throw the saddle 26 away from the pipe, allowing it to clear-the shoulder. As the dispenser is moved on, the wheel 31 is turned through 900 so that there are still two sliding fingers, the previous leading one becoming the trailing one, and the "spare" forwardly projecting finger becoming the new leading sliding one.

The source of foam may be other than a portable canister 1. In that case, a handle 33 such as that shown in Figure 7 may be used. It can screw into the barrel 2 in the same manner, and it has an internal conduit 34 which is taken beyond the free end of the handle to a pipeline and the other source of foam.

The preferred foam will be polyurethane, which is strongly adhesive to most surfaces. To keep the dispenser serviceable, therefore, the parts with which the foam comes into contact will be made of a substance, or have a coating, to which the foam will not stick, or at least from which it can be relatively easily peeled after hardening. Although the star wheel (which may have other than four fingers) will normally be ahead of and untouched by the foam, this should preferably be made easily removable for cleaning.

Polyurethane foam also allows the pipe cladding itself to be cut, shaped or abraded, and to be painted if desired.

Sections can easily be removed for pipe repair, or for the fitting of a branch pipe for example.

In more advanced dispensers there may be a sensor associated with the saddle to signal when that is properly engaged wlth a pipe. This may be used to govern a valve in the foam supply: unless the head is correctly positioned, there will be no flow. In addition, there could also be a pipe follower, to indicate the speed of traverse, and this signal could be used to govern the foam dispensing. The rate would be automatically commensurate with the speed of traverse, and reliance would not have to be placed on the operator's skill to achieve a uniform coating.

Claims

1. Apparatus for insulating pipes comprising a dispenser of liquid but expandible and rapidly setting foam, ~the delivery end of which has a head for embracing a pipe and for guiding dispensed foam around the pipe, and means for locating the head with respect to the pipe while permitting movement of the head along the pipe.

2. Apparatus as claimed in Claim 1, wherein the head is generally C-shaped to be fitted over the pipe laterally.

3. Apparatus as claimed in Claim 2, wherein the dispensed foam emerges substantially centrally into the convexity of the C.

4. Apparatus as claimed in Claim 1, 2 or 3, wherein the head is rotatable with respect to the rest of the dispenser about the mouth of the foam conduit.

5. Apparatus as claimed in any preceding Claim, wherein the head is removable from the rest of the dispenser. < & Z,

6. Apparatus as claimed in Claim 5, wherein there is a set of exchangeable heads adapted for different sized pipes.

7. Apparatus as claimed in any preceding Claim, wherein the locating means comprise an element shaped to engage a portion of pipe just ahead of the foam as it is dispensed.

8. Apparatus as claimed in Claim 7, wherein the element is a fixed part of the head and slides along the pipe.

9. Apparatus as claimed in Claim 7, wherein the element is rotatable and rolls along the pipe.

10. Apparatus as claimed in Claim 7, wherein the ~element is composite, having a fixed portion to slide along the pipe and a toothed rotatable portion which also slides along the pipe by means of a pair of adjacent teeth the leading one of which, when an obstruction such as a pipe joint or supporting strip is reached, engages that obstruc tion and acts as a trip to lift the fixed portion over the obstruction; the rotatable portion turning with respect to the fixed portion and the leading tooth becoming the trailing one of another sliding pair.

11. Apparatus as claimed in Claim 10, wherein the toothed rotatable portion is a pointed star-like wheel.

12. Apparatus as claimed in Claim 10 or 11, wherein the toothed rotatable portion is removable from the fixed portion.

13. Apparatus as claimed in any preceding Claim, wherein there are means for sensing the relationship of the head to the pipe and for permitting foam dispensing only when the head is properly located with respect to the pipe.

14. Apparatus as claimed in any preceding Claim, wherein there are means for detecting progress of the head along the pipe and for governing the delivery of foam in accordance with such progress.

15. Apparatus as claimed in any preceding Claim, wherein there are means4 settable by the operator, to govern the delivery of foam in accordance with the size of the pipe.

va

16. Apparatus for insulating pipes substantially as hereinbefore described with reference to the accompanying drawing.

17. A method of insulating pipes wherein foam is dispensed using apparatus as claimed in any preceding Claim.