Joining Large PE Pipes in No Time at All: Integration of large connecting lines made easy

Transcription

1 SAFE JOINING TECHNOLOGY ON A GRAND SCALE FRIALEN XL Offprint Joining Large PE Pipes in No Time at All: Integration of large connecting lines made easy by Dipl.-Ing. (FH) Robert Eckert Technical journal for piping system integrity and efficiency, Vulkan-Verlag GmbH, Essen

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3 Water & Gas Distribution Joining Large PE Pipes in No Time at All: Integration of large connecting lines made easy By Robert Eckert The first part of this technical report [4] on the jointing technology for large PE pipes presented the new conical ring coupler technology (Figure 1, 2): The mechanical compensation of extremely large gap ratios between coupler and pipe greatly simplifies the assembly of the coupler. This is specifically of great importance when integrating a fitting piece during which the coupler has to be slipped on the pipe section with its entire length. After the assembly, a zero gap situation is achieved. This not only reduces the fusion and cooling times dramatically, the adjustability of the fit also leads to an optimal and above all reproducible joining quality, independent of the varying pipe parameters. This second part is now to describe the usability of saddle component parts. The production of branches with large dimensions hitherto required the use of T pieces. With an increasing pipe diameter, the costs for the fittings typically produced in very low volumes escalate disproportionately. In addition, there is the expense of integration technology and above all the interruption of the piping operation. Novel saddle fittings provide comfortable and economic options. PRODUCTION OF BRANCHES The practice of integration to supply lines The separation of a line section for integrating into gas and water supply systems always requires a lot of time and major effort (Figure 3). Apart from the considerable time required to perform the task, it is above all the extent of the underground work, the restoration of the surface, the required shutting-off equipment as well as the number of fittings required for the necessary bypass, if any, to maintain the supply and for the actual integration which cause considerably costs. But it is not only financial aspects which are of significance: The objective of customer-orientated line operators must be to keep the interruption of the operation in the private as well as industrial field as low as possible. FIG. 1: Conical ring coupler, consisting of two fusion wedges and the coupler body. Bottom fusion conical ring before assembly, top bottom conical ring in final position FIG. 2: Functioning of the fusion conical ring: The flex grooves permit a diameter reduction such that the joint gap between the pipe and the fusion conical ring is bridged 3

4 Water & Gas Distribution FIG. 3: Expensive! Integration of a branch in a gas line d 500 Branches for house service connections, ventilations or gauging connections for pipings up to d 630 mm Saddle fittings can be installed and fused to large pipes from d 250 mm to d 630 mm using the top-loading method (Figure 4, 5). Thanks to the flexibility of the component part, the entire dimension range from d 250 to d 630 mm can be covered with one single fitting. The top-loading method is also uniquely suited for pipes with an outer diameter beyond the standard such as project specific dimensions e.g. for refurbishment using the relining or close-fit methods. The know-how is integrated in the clamping technology: A pneumatic spring element in the FRIATOP clamping unit transfers the clamping force to the saddle area. The spring force automatically controls the jointing pressure during fusion to achieve the optimal sealing and pressure distribution in the melt. This method facilitates the production of house service connections and branch lines under operating pressure and without interrupting the supply, e.g. with a tapping ball valve (Figure 6). Connecting high volume branches with vacuum clamping technology Think big : Problem solution for large dimensions FRIALEN XL spigot saddles SA-XL facilitate the connection of branch lines to large pipe diameters in the range of d 315 to d 1000 (Table 1). Although ranged dimensions are not possible, special component parts can be produced for specific pipe diameters. FIG. 4: Venting spigot at a drinking water line d 450 using a top loading spigot saddle SA-TL Design of the fusion zone The exposed heating coil in the saddle fusion zone facilitates an optimal heat transfer to the pipe during fusion. TABLE 1: Programme range for spigot saddle SA-XL FIG. 5: House service connection through a pressure tapping tee DAA to a drinking water line d 400 using the top loading method Main pipe d1 [mm] Branch d2 [mm] Design / Pressure stage [bar] d315 d225 d250 SDR11 MOP10 PN/PFA16 d355 d225 d250 SDR11 MOP10 PN/PFA16 d450 d225 d250 SDR11 MOP10 PN/PFA16 d560 d160 d225 SDR17 MOP5 PN/PFA10 d630 d160 d225 SDR17 MOP5 PN/PFA10 d710 d160 d225 SDR17 MOP5 PN/PFA10 d800 d160 d225 SDR17 MOP5 PN/PFA10 d900 d160 d225 SDR17 MOP5 PN/PFA10 d1000 d160 d225 SDR17 MOP5 PN/PFA10 Other dimensions / pressure stages an request 4

5 FIG. 6: Top-loading tapping ball valve: combination of saddle fitting and shut-off valve for pipes up to d 560 FIG. 7: Production of a branch on a gas line d 315 under operating pressure with the FRIALEN XL spigot saddle SA-XL FIG. 9: The vacuum clamping is made using the plunger and the VACUSET XL (consisting of a cased venturi nozzle, a manometer as well as connecting hoses) FIG. 8: Principle of spigot saddle SA-XL assembly with vacuum clamping technology The pipe surface is directly melted on and thus guarantees an enhanced material mixing of the two joining partners. The jointing area is thus enlarged and the mutual penetration of the molecule chains enhanced. An excellent fusion quality with high strength is achieved even under rough construction site conditions. Additional reliability is provided for by the size of the fusion area compared to the pressurised area. The extra-broad fusion zone results in low specific tensions both under operating pressure and under the external loads resulting from the installation and operating conditions. Vacuum clamping technology: New ways for an application-friendly and reliable assembly Simple assembly, comfortable handling and a short processing time are the objectives in the development of optimised fittings with regard to a construction site-appropriate clamping method of large saddle fittings: The traditional assembly for saddle fittings with underclamp or with the top loading belt requires access to the whole of the pipe all-around. Thanks to the clamping method specifically developed for SA-XL, only access to the covered saddle area is required. Specifically in the case of connections to existing pipelines, the bedding in the pipeline zone is only disturbed as absolutely necessary. The clamping force of the saddle required for fusion and build-up of the jointing pressure is applied by a vacuum (Figure 8). For this purpose, a circumferential sealing element is integrated in the saddle jacket. This sealing element is designed so that both the typical processing marks are bridged by scraping the pipe surface and the pipe s out-of-roundness is compensated for. The outlet 5

6 Water & Gas Distribution FIG. 10: SA-XL d 900 with flange outlet during assembly using the vacuum clamp-ing technology. The outlet here is closed with a blind flange instead of the usually used plunger FIG. 11: Tapping of a pipe d 900/SDR17 of a wall thickness of approx. 53 mm using the tapping kit FWAB XL spigot is closed by a plunger (Figure 10). The plunger is selected depending on the diameter of the outlet spigot. The vacuum required to clamp the SA-XL is generated by a venturi nozzle with the help of a compressor usually used at construction sites. The required equipment is combined for the user s comfort to form the VACUSET XL package (Figure 9) and is used together with the plunger. The vacuum results in a clamping force between 5-10kN depending on the dimension such that the saddle jacket has a close fit with the pipe. This facilitates very short fusion times and thus also short cooling times. The piping can therefore be very quickly reconnected (Figure 10). The saddle can be fixed at any position on the pipe. The vacuum clamping technology only requires a few accessories, but above all the space required in the pipe trench and the necessary access to the pipe are minimised. Out-of-roundnesses and shape deviations of the pipe usually seen at construction sites are bridged by the clamping method. Tapping Using the tapping kit FWAB XL, even thick-walled pipes can be tapped with little effort (Figure 11). For this purpose, a hole saw is used which is driven by a drilling machine. The tapping kit FWAB XL is matched to the system requirements with regard to a maximum, almost flush tapping diameter, the maximum pipe wall thickness (Figure 12) as well as the length of the tapping rod. The tapping diameter is almost identical with the pipe s diameter of the outlet spigot so that only minimal pressure losses result. For tapping under operating pressure, special accessories and a lock fitting are required. SPIGOT SADDLE AND T-PIECE: COMPARISON The integration of a branch line using a spigot saddle offers benefits from the economic and application-technical point of view and processing is also very quick. For the production of an outlet spigot according to Table 2, the following times are required in general. Preparation of the fusion area, removal of the oxide layer, cleaning: 10 min Clamping of the saddle, connection with the electrofusion unit, fusion: 10 min Cooling until tapping after end of fusion time: 10 min Pressurisation / pressure test after end of fusion time: 60 min FIG. 12: Full-port tapping of the pipe d 900 with flange outlet DN 150 CONCLUSION Excellent experiences have been gained in numerous areas of application with PE pipes in large dimensions. The advantages of the material and the jointing method, the 6

7 TABLE 2: Connection of a branch: Comparison of the methods Criterion / method Integration of T-piece Assembly of the spigot saddle Underground work Construction site safety, impairment of traffic Restoration of surface De-commissioning, draining of piping Time expense, duration of interruption of operation Required equipment, tools Large trench required, additional excavation for bypass might be necessary Corresponding to underground work Corresponding to underground work Required, possible safety cordoning High, because of draining the piping and integrating the T-pipe Standard Head access hole sufficient Corresponding to underground work Corresponding to underground work Commissioning under operating pressure possible Commissioning possible within one hour, possibly without interrupting the piping operation Little accessories required: Vaccum equipment, drilling equipment Literature [1] DVGW-W400 Technical Rules Water Distribution (TRWW), Part 2: Construction and testing of water distribution facilities, 09/2004 [2] DVGW-G472 made of PE80, Pe100 and PE-Xa Erection ( ) [3] DVGW leaflet GW 335 Plastics piping systems in the gas and water supply, requirements and testing - Parts A2, B2 [4] Eckert, Robert: Joining Large PE Pipes in No Time at All: A new generation of electrofusion, 3R international, issue 3/2011 [5] Eckert, Robert: Electrofusion as means to reduce costs in piping construction? Energie Wasser Praxis, June 2001 [6] Eckert, Robert: Use of electrofusion in PE pipes of large nominal diameters of up to d710, 3R international, issue 4-5/2004 [7] FRIALEN safety fittings, assembly instruction for laying large bore pipes, 2006 [8] Eckert, Robert: Integration, shut-off and repair technology for PE pipe systems, Plastics Pipes XII, Mailand, 2004 electrofusion welding, lead to technical and economic optimisation with regard to installation, operation and life. The conical ring coupler technology, which was presented in the first part of this technical report, revolutionises the joining technology in the field of large pipes. The assembly process of the fitting is fundamentally simplified when compared to traditional cylindrical couplers. New fittings and innovative installation methods as presented here taking the spigot saddle XL and the vacuum clamping technology as an example tap the full cost-saving potentials and thus in addition increase the attractiveness of PE piping systems also for large pipes! Author DIPL.-ING. ROBERT ECKERT FRIATEC AG, Mannheim Tel robert.eckert@friatec.de 7

8 SAFE JOINING TECHNOLOGY ON A GRAND SCALE FRIALEN XL Offprint FRIATEC Aktiengesellschaft Technical Plastics Division POB D Mannheim Tel Fax info-frialen@friatec.de FRIATEC AG TECHNICAL PLASTICS DIVISION / FRIALEN XL