Relining is a trenchless method of rehabilitation and restoration of pipelines , when a new pipeline is laid inside an existing pipeline without opening (or with partial opening), as well as without dismantling the old pipeline.
One option is to lay new pipes in the old pipeline. In this case, the old pipeline opens in several places, through these places new pipes are delivered, which, one after the other, move inward, forming a new pipeline. Most often, the space between old and new pipes is filled with cement-sand mixture or other aggregates to distribute the load and restore stability.
The pipe-in-pipe method consists in pulling a smaller diameter continuous pipe inside an existing pipeline.
Another option that does not require opening the old water supply system and filling the space between the new pipe and the old one is sanitation by the “stocking” method (sanitation with a polymer sleeve), in which a flexible composite sleeve is introduced into the pipe to be reconstructed, which after opening and curing is a new heavy-duty pipe, fully absorbing all loads.
Content
The stocking method (sanitation with a polymer sleeve)
The “stocking” method (sanitation with a polymer sleeve) is one of the options for relining. It is characterized by the fact that a flexible composite sleeve is introduced into the pipe to be restored, which, after curing, is a new pipe that completely takes over all the functions (including the bearing function) of the old one. The main features that distinguish this method of pipeline reconstruction from other relining options are:
- high speed of work;
- the ability to carry out work regardless of the environment in which the pipe is to be reconstructed (concrete, soil, stone, etc.);
- the possibility of carrying out work regardless of the material from which the pipe to be restored is made;
- lack of need for destruction of collectors and expansion of sewer wells ;
- the ability to reconstruct long stretches continuously;
- a high degree of adaptation of the new pipe to the changing cross section of the old.
To date, the most promising is the “stocking” sanitation technology created in Germany at the end of the 90s and further improved in the future, based on the use of ultraviolet radiation to cure the polymer sleeve. This method found its widest application in sanitation, as well as culverts.
The use of ultraviolet radiation made it possible to abandon thermosetting polymer resins , which had previously impregnated composite hoses, and, as a result, significantly reduced the sensitivity of the technology to the influence of external factors. The result of the use of photoreactive polymer resins used in sanitation with the help of ultraviolet radiation was, first of all, an increase in the shelf life of polymer sleeves up to 6 months without restrictions on storage temperature, as well as resistance to changes in ambient temperature. In turn, the above advantages made it possible to impregnate composite hoses in a production environment, which significantly improved its quality and reduced the time for rehabilitation, while it was usually necessary to carry out the impregnation with thermosetting resins on their own directly at the construction site.
In order to increase the curing rate and the quality of the final sanitation product, in parallel with the introduction of UV radiation as a catalyst for the polymerization process, significant changes were made in the design of the composite sleeve itself. The needle-punched glass mats were replaced by fiberglass , which has higher strength characteristics, which significantly reduced the wall thickness of the sleeve and, as a result, reduced the loss of the working section of the pipe as a result of rehabilitation to almost zero. An important result of improving the design of a fiberglass sleeve is to reduce its weight by reducing the wall thickness, which significantly facilitated the rehabilitation process itself.
Remediation Process Description
There are five main stages of the process of pipeline reconstruction using the "stocking" method:
- 1. Pipeline preparation
Pipeline preparation includes: tele-inspection of the pipeline, isolation of the area to be sanitized and, if necessary, cleaning, usually carried out using hydrodynamic flushing.
- 2. A broach of a composite sleeve.
After laying on the bottom of the pipe to be reconstructed, a special protective polyethylene film, a polymer sleeve is drawn, which is tightly closed at both ends by special plugs (packers) equipped with nozzles for supplying air.
- 3. Controlled calibration (inflation) of the sleeve , usually performed using a compressor.
A flexible fiberglass sleeve is inflated with air, after which it takes the form of a restored pipeline, adjacent to its walls and forming a new pipe inside the old one. The process is controlled by the operator using special cameras that are equipped with UV emitters.
- 4. Curing of the fiberglass sleeve using ultraviolet radiation.
After calibration, the UV emitters, previously inserted in the sleeve, are pulled from one end to the other at a given speed controlled by the system.
- 5. Quality control by means of cameras mounted on UV emitters and dismantling of packers.
After curing the composite sleeve, the UV emitter returns to its original position. In the process of moving it, the operator performs quality control of the work performed.
So, in the shortest possible time, a new fiberglass pipe is created in the old pipe, which is characterized by ultra-high strength and reliability. The smooth and abrasion-resistant inner surface of the pipe largely functionally compensates for the small loss in diameter.
See also
- Pipeline laying
Literature
- Fomin K. Methods of rehabilitation of pipelines for water supply and sanitation // Plumbing, heating, air conditioning: a journal. - M .: LLC Publishing House "MEDIA TECHNOLOGY", 2011. - No. 10 (118) . - S. 20-24 . - ISSN 1682-3524 .
- Gornev Yu. V., Kudryavich B.S. Pipeline renovation : Danish stocking, Russian robot // Water supply and sanitary equipment: journal. - M .: LLC "Publishing House VST", 2003. - No. 5-1 . - S. 26-27 . - ISSN 0321-4044 .
- Agapchev V.I., Fattakhov M.M. et al. Modern trenchless technologies and new engineering solutions in the reconstruction and restoration of pipeline systems // Problems of the collection, preparation and transport of oil and oil products: journal. - Ufa: Institute for Energy Transport of the Republic of Bashkortostan, 2006. - No. 66 . - S. 242-253 . - ISSN 1998-8443 .
- Orlov V.A. Trenchless restoration of pipelines // Energy: Economics, Engineering, Ecology: Journal. - M .: Publishing House "Science" RAS, 2003. - No. 4 . - S. 33-35 . - ISSN 0233-3619 .
- Khramenkov S. V., Primin O. G., Orlov V. A. Trenchless methods of pipeline restoration: a training manual. - 2. - M .: Prima-Press-M, 2002 .-- 284 p. - ISBN 5-93310-041-2 .
Links
- Restoration (sanitation) of the pipeline by the method of "stocking" . AF Verbindung . AFVerbindung.ru . Date of treatment January 28, 2014.
- Installation of Berolina-Liner . BKP Berolina . www.bkp-berolina.de . Date of treatment January 29, 2014.
- Trenchless repair of utility pipelines . Argus group. Date of treatment March 3, 2014. *