WO1999063262A1

WO1999063262A1 - Device for deposition in ditches for pipes, cables etc.

Info

Publication number: WO1999063262A1
Application number: PCT/NO1999/000152
Authority: WO
Inventors: Per Knut MÖLSTAD
Original assignee: Mjösplast As
Priority date: 1998-06-02
Filing date: 1999-05-11
Publication date: 1999-12-09
Also published as: NO982496L; NO307355B1; NO982496D0; EP1101060A1

Abstract

Element for depositing in ditches and cavities in the ground, for laying pipes, cables and similar parts, previous to filling with filling material, and/or for founding brick walls and other immersed structures. In use the element is laid close to the pipe or the like, during placement. The element includes a sleeve which is filled with a filling material with insulating characteristics. The sleeve is a closed, liquid-tight long bag (20) which is filled with a powdery, fibre-shaped or granular material (21), which in unfolded condition is shaped as a pillow or blanket.

Description

Device for deposition in ditches for pipes, cables etc.

The invention relates to an element for founding and protecting pipes and cables and the like, in ditches and other structures which are immersed in the ground, more precisely an element according to the preamble of patent claim 1.

Background

In various applications it is necessary to place objects, such as pipes, cables, plinths, foundation walls, etc, into the ground. It is, in this relation, usual to place sand and/or gravel in a pre-made ditch, or cavity, to provide a foundation for the pipe or the like, to be laid in the ditch or cavity. After the pipe, for example a plastic pipe is placed, more sand is used to cover the pipe to ensure it stays in place, and to prevent damage to the placed pipe. When the placement is ditches in soil, it is common to used 1 kbm sand for each metre of ditch. Corresponding use of sand arises in other types of founding in soil and loose foundations.

It is also known to use sandbags for building up structures. But known sandbags are not well suited for use in ditches along pipes and cables and other long structures.

In such cases, it is also desirable to increase the thermal insulation, for example for pipes carrying liquids that are sensitive to freezing. Various approaches have been suggested to aid in the placing of pipes in a foundation. From US-patent 4477206 (Papetti et a ), it is known to place a protective ballast-blanket over pipes at the bottom of the sea. The intention is to keep the pipe down and to protect it against damage. The ballast blanket contains rocks, sand, gravel and other different mineral filling materials. From US-patent 5099899 (Ratzlaff) it is known to encase a pipe in a protecting blanket of impact-absorbing material, such as filaments of thermoplastic and elastic material united in a blanket. This material must be placed completely around the pipe, and fastened in the overlap. This protective blanket is only impact-absorbing, and is not especially suited for providing a stable placement. From UK-patent 2231273 (Micropore Int.) it is known to place a blanket with thermal insulating particles in a sleeve around a pipe, in order to insulate it thermally. But this solution is not practical and economically suited for impact protection of plastic pipes which are to be laid in a ditch filled with gravels and rocks. From SE patent 463481 (Polarn Innovation) a thermal insulating blanket is known which can be bent around a pipe to thermally insulate ventiducts in buildings. This solution is very limited regarding use in foundations.

From German patent-publication 3530052 (Knebel) it is known to make blankets filled with peat for thermal insulation, but these, also, are not suited for use in foundation.

There is therefore no satisfactory element for protecting buried constructions, especially plastic pipes, which are to be placed in a ditch and covered with a material which contains rocks. There is not known any element which may replace sand filling in ditches or cavities in the ground.

Object

The main object of the present invention is to create a flexible element, to replace the use of sand in ditches and the like. The elements must have several functions, but particularly to provide protection against impacts and abrasion, and to provide thermal insulation. Further- more it must account for displacements caused by frost, so that the pipe or the foundation wall will not be damaged.

It is also an object to create an element which reduces the need for mass-filling which further allows shallower placement of the pipe, so that less ditch-digging is necessary.

It is further an object to provide an element which may be used several times. Finally it is an object to provide an element which is easy to transport to the place of use, and which may be laid down during the digging. The aim is that contractors, and other users, will spend less time carrying out the founding and cover-works on which the element is to be used.

The invention

The invention comprises mainly an element according to patent claim 1. Such an element may be made of raw materials for moderate costs. It may replace the whole or part of the sand filling. Thereby it is possible to, for example, place pipes during digging, without waiting for filling of sand foundation and without refilling sand. This means that ditches can be finished directly after the placement, without adding material from outside.

The elements according to the invention may be designed in different ways, and may be placed in a ditch as described in more detail below. Further features of the invention are given in patent claims 2-9. Example

The invention is shown in the figures, where:

Fig. 1 shows in cross section a ditch with a pipe placed on the element according to the invention, Fig. 2 shows in a perspective view an element according to the invention with two compartments filled with granular material, Fig. 3 shows in cross section an unfolded element with two compartments, Fig. 4 shows in cross section an element with three compartments, Fig. 5 shows how two elements according to Fig. 3 may be used to cover a pipe, and Fig. 6 shows how an element according to Fig. 4 may be used to protect a pipe.

Fig. 1 shows a flat bottom ditch 11. In this ditch is placed an element 12 according to the invention, as a foundation for a pipe 13. With the element 12 under the pipe 13, the risk for sharp rocks cutting into the pipe is removed. Above the pipe the ditch 11 may be filled with normal dug out material 14, preferably with an element 15 corresponding to the element 12, placed on top of the pipe 13.

Fig. 2 shows an example of an element according to the invention. The elements 12, 15 may be produced of a long bag of tight plastic foil, which is filled with granulated or powdery filling material, and sealed, so that a flat pillow or "hot dog" shape which does not let in moisture is formed, and which is not cut or punctured by the surroundings in the ditch. Details and variants of this are further described in the following. The filling material may have particle or mesh size preferably up to about 15 mm. It may, for example, be made of granulated plastic waste, especially grinded, recycled plastics, such as thermosetting plastic, for example polyester and polyurethane. Other filling materials may also be used, but not with the same economical and technical advantages.

The filling material may comprise dense particles. This will provide greater strength towards outer stress, than by use of porous particles. The thermal insulation will then be dependent on air between the particles. Therefore it is important that the cover material of the elements is completely waterproof, both on the surface, and in the joints. Fig. 3 and 4 show two examples of elements which are made as longitudinal "hot dogs" with two 16A, B and three compartments 17A B and C, respectively, which are joined with longitudinal tight or partly open seams, for example by welding the plastic. The sides and the ends are closed, so that the filling material will be kept in place and protected against penetration of moisture and pollution. Fig. 5 shows how two elements, each with two compartments, 16A and B, may be laid under and on top of a pipe 18. Such an assembly will provide both thermal insulation and mechanical protection.

Fig. 6 shows how one element 17 A-C may be used as a side-covering groundsheet, for a pipe 19. In this application the pipe 19 will be protected against physical stress, for example, from sharp rocks in the foundation.

An assortment of elements with one, two and three compartments may be used in different ways in order to create a groundsheet, side-packing or surface coat for pipes and other elements which are buried, for example as a foundation for poles. The elements may be transported to the building place on pallets, which may be placed close to the work-site. Thus, the laying will be simple and quick.

Examples of the present invention are outlined below, with figures.

Example 1 - Pillow with two compartments

The size of the pillow maybe for example, 1300 x 450 mm (flat) and the material may be 0,015 mm thick polyethylene. Two compartments which are 1300 x 225 mm will be made with a longitudinal welding seam. Finished pillows (with filling) will thus cover 1200 x 400 and it will be possible to pack them in two piles, with 10 pillows, side by side on a normal EUR pallet during stocking and transport. During installation in ditches, to protect water pipes, one pillow may be laid in the bottom of the ditch before the water pipe is placed in the middle of the welding seam on the pillow. On top of the pipe, a new pillow is placed in the same direction as the lowermost. The contents of one pallet will cover 12 metres of pipe. This corresponds to about 10-12 cubic metres of sand used for conventional pipelines placement. This means that the transportation need is dramatically reduced, and delays for the transporter will be eliminated. In addition to these advantages, the product is also to some extent insulating, so that the ditches do not need to be dug as deep as previously necessary. The progress of the digging will also be more effective because the mechanical digger may close the ditch continuously. The pillows may be filled with, for example, granulate of used thermoset plastic, which in this way is recycled for use in beneficial products. Example 2 - Pillow with three compartments

Similar construction to example 1 , but the pillows have three longitudinal compartments instead of two. The width of the pillow maybe, for example, 800 mm. They will then constitute three compartments with width 275 + 250 + 275 mm. In this example, the pipe or body which is to be protected, will be laid on the middle compartment and the other two will be folded up against the sides.

As covering for the pillows, a plastic foil or tight fabric, meaning a textile material with a plastic film, may be used. For example, it may be used a plastic foil with an embedded net of reinforcement, or reinforcement-threads, or pure polyethylene foil. The cover of the pillow may be any colour, but it is especially advantageous to use a signal- or warning colour, as a marker for later digging.

The element may be made with more than three compartments side by side, for example, in the shape of a blanket. The compartments may also be divided by transverse partition walls, for example in order to prevent transverse buckling, in those cases where the elements should be used against special structures, for example inserting pipes in foundation walls.

The element according to the invention may be used for founding in connection with earth based constructions or, as a replacement for sand and gravel, for example in connection with foundation walls. The element may be filled with different sand and gravel particle sizes and with granulated waste materials from different chemical processes or other dead return material. The filling material maybe, for example, a pulverized insulation material of polyurethane which is processed with freon. An alternative is to use a fibre material, for example, wood, paper or cellulose pulp. The ratio of filling material to overall volume in the element may be 90- 100 %.

Another alternative is to use finely cut rubber for emample from used vehicle tires.

Claims

Claims:

1. Element for depositing in ditches and cavities in a foundation, for laying pipes, cables and similar parts previous to filling with filling material, and/or for founding brick walls and other immersed structures, wherein, in use the element is layed against the structure tp be embedded during the depositing, wherein the element has a sleeve filled with a filling material with isulating properties, characterized in that the sleeve comprises a closed, liquid tight bag (20), having a substantially greater length than width, and a substantially greater width than thickness and which is filled with a powdery, fibre shaped or granulated material (21), in such a way that, in an unfolded condition, has the form of a pillow or blanket.

2. Element according to claim 1, characterized in that the sleeve is assembled of two (16 A, B) or more (17A, B, C) longitudinal compartments.

3. Element according to claim 2, characterized in that the longitudinal compartments are divided crosswise.

4. Element according to anyone of the claims 1-3, characterized in that the sleeve is made of polyethylene sheeting or another fibre- reinforced plastic foil, preferably in signal colours.

5. Element according to anyone of the claims 1-4, characterized in that the filling material has a mesh size up to 15 mm.

6. Element according to anyone of the claims 1-5, characterized in that the filling material includes fine-granulated plastic waste.

7. Element according to claim 6, characterized in that the filling material includes a fine-granulated insulation material such as polyurethane produced with freon.

8. Element according to anyone of the claims 1-7, characterized in that the filling material includes a fibrous material, for example wood, paper or chemical pulp.

9. Element according to one of the claims 1-8, characterized in that the ratio of filling material to overall volume of the element is 90-100 %.