WO1991015634A1

WO1991015634A1 - A method for renovating wells

Info

Publication number: WO1991015634A1
Application number: PCT/FI1991/000084
Authority: WO
Inventors: Christer STORGÅRD; Gunnar Blomqvist
Original assignee: Oy Kwh Pipe Ab
Priority date: 1990-03-30
Filing date: 1991-03-27
Publication date: 1991-10-17
Also published as: FI901619A; FI84384B; FI84384C; FI901619A0

Abstract

The present invention relates to a method for renovating wells, especially drain wells, and is characterized in that semi-circular ring elements (3, 3a) with a smaller diameter than the inner diameter of the original well are led into the old well through an opening (2), which ring elements (3, 3a) are stacked concentrically and by pairs on top of each other in the well to a desired height, after which the gap between the old well rings (1) and the new ring elements (3, 3a) is filled with concrete (6).

Description

A method for renovating wells

The present invention relates to a method for renovating wells, especially drain wells.

Old drain wells made of concrete rings tend to become untight in the course of time partly because the rings located above the frost limit lift out of position when the frost is beaking up, and partly as a result of corrosi¬ on. The concrete rings and pipes used in old drain pipe systems corrode at an ever-increasing rate for example as a result of the increasing use of strong detergents.

There is nowadays a large number of methods for renovating drain pipes, by means of which methods it is relatively simple to prevent leakages in the drain pipes themselves. Since the pipe drains have been tightened, the pressure in the wells incorporated into the drain pipes increases, which further increases the need for finding a simple method for renovating the wells themselves.

This has been achieved by means of the inventive method, which is based on the fact that semi-circular ring elements with a smaller diameter than the inner diameter of the original well are led into the old well through an opening and that the ring elements are stacked concentrically and by pairs on top of each other in the well to a desired height, after which the gap between the old well rings and the new ring elements is filled with concrete.

By means of this method, a completely tight well is ob- tained, which is not affected by corrosion or frost. Suita¬ ble materials for the ring elements include polyurethane, polyester, epoxy, polyethene, polypropylene, light concre- te, etc. The remaining characteristics of the invention are given in the appended claims.

The invention is next described in more detail with refe- rence to the drawing, in which

Fig. 1 shows schematically in section a sideview of a well renovated according to this invention, and

Fig. 2 shows an example of a ring element according to the invention, seen from above.

The object of the invention is to renovate old wells, especially wells made of concrete rings 1, which wells have become untight as a result of corrosion or mutual movement of the concrete rings 1. The renovation is performed so that semi-circular ring elements 3 with a smaller diameter than the inner diameter of the original well are led into the old well through an opening 2. The advantage of using semi-circular ring elements 3 is that they can be led simply into the well through the conventional opening 2 without having to remove any concrete covers. The first pair of ring elements 3 is placed concentrically on the bottom of the old well and joined together e.g. by rive- ting. The eventual gap between the bottom and the ring elements 3 is then tightened in a suitable manner. The next pair of ring elements 3 is placed above the first pair of ring elements 3 and joined together. The ring elements 3 placed on top of each other are kept in position by conven- tional, co-acting joint grooves 4 along the upper and lower edge of the ring elements 3. In order to obtain the best possible strength for the construction, the ring elements 3 located on top of each other are placed so that they overlap each other, whereby the vertical seams 5 between the respective pair of ring elements 3 are located on different planes. The joint grooves 4 then affect such that they keep each pair of ring elements 3 together. The best possible strength is obtained, if the ring elements 3 on two layers on top of each other are turned 90° in relation to each other. When the desired height is reached, the gap between the old well rings 1 and the ring elements 3 is filled with concrete 6, whereby a completely tight and corrosion resistant well is obtained, which is not affected by frost either.

As the ring elements 3 are stacked on each other, the necessary openings for side channels 7 are formed therein, whereby the pipe line eventually "relined" already pre¬ viously is extended through the new ring element wall and tightened e.g. with a so-called fastening, which is fixed to the inner wall of the ring element 3 around the extended pipe end.

The ring elements 3 are preferably made of polyurethane, polyester, epoxy, polyethene, polypropylene, light concrete or the like by casting in a closed form or by centrifugal casting. According to a preferred embodiment, the form is filled only partially with a plastic mass containing an expansion medium, which mixture after the expansion fills the entire form. A suitable foaming degree is obtained, when a ring element 3 of polyurethane has a density of ca. 0.2 - 0.6 cm³.

The main part of the ring elements 3 forms during the joining a cylinder, but the uppermost pair of ring elements 3a can preferably have a form, which results in a trunca- ted, eventually slanting cone, especially, if the old concrete well is built with a corresponding form.

The polyurethane ring elements 3 preferably have a height, which is slightly smaller than the height of the concrete rings 1.

Claims

1. A method for renovating wells, especially drain wells, c h a r a c t e r i z e d in that semi-circular ring elements (3, 3a) with a smaller diameter than the inner diameter of the original well are led into the old well through an opening (2) and that the ring elements (3, 3a) are stacked concentrically and by pairs on top of each other in the well to a desired height, after which the gap between the old well rings (1 ) and the new ring elements (3, 3a) is filled with concrete (6).

2. A method according to Claim 1, c h a r a c t e r i ¬ z e d in that the ring elements (3, 3a) are upwards and downwards provided with conventional co-acting joint groo¬ ves (4) .

3. A method according to Claim 2, c h a r a c t e r i ¬ z e d in that as a pair of ring elements (3, 3a) is placed in position, they are joined together e.g. by riveting.

4. A method according to Claim 3, c h a r a c t e r i ¬ z e d in that the ring elements (3, 3a) are stacked on top of each other so tha the vertical seams (5, 5a) between respective pairs of ring elements (3, 3a) are located on different planes.

5. A method according to Claim 4, c h a r a c t e r i ¬ z e d in that as the ring elements (3, 3a) are stacked upon each other, necessary openings for side channels (7) and the like are formed.

6. A method according to any of the preceding Claims, c h a r a c t e r i z e d in that the ring elements (3, 3a) are cast in a closed form.

7. A method according to Claim 6, c h a r a c t e r ! - z e d in that the ring element is made of polyurethane, polyester, epoxy, polyethene, polypropylene, light concrete or the like.

8. A method according to Claim 6, c h a r a c t e r i ¬ z e d in that the form is only partially filled with a plastic mass containing an expansion medium, which mixture is allowed to expand, until it fills the entire form.

9. A method according to Claim 8, c h a r a c t e r i ¬ z e d in that the ring element (3, 3a) is made of poly¬ urethane and foamed to a density of ca. 0.2 - 0.6 g/cm³.

10. A method according to any of the preceding Claims, c h a r a c t e r i z e d in that the ring elements (3) stacked by pairs form a cylinder or a truncated cone, which is eventually slanting.