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

SAFE JOINING TECHNOLOGY ON A GRAND SCALEFRIALEN® XL Offprint

www.frialen-xl.com

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

By Robert Eckert

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 ex-tent of the underground work, the restoration of the sur-

face, 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 cus-tomer-orientated line operators must be to keep the in-terruption of the operation in the private as well as indus-trial field as low as possible.

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.

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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

Water�&�Gas�Distribution

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 re-lining 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 con-trols the jointing pressure during fusion to achieve the optimal sealing and pressure distribution in the melt. This method facilitates the production of house service con-nections 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 connec-tion of branch lines to large pipe diameters in the range of d 315 to d 1000 (Table 1). Although ranged dimen-sions are not possible, special component parts can be produced for specific pipe diameters.

Design of the fusion zone The exposed heating coil in the saddle fusion zone facili-tates an optimal heat transfer to the pipe during fusion.

TABLE 1: Programme range for spigot saddle SA-XL

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Water�&�Gas�Distribution

Main piped1 [mm]

Branchd2 [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 requestFIG. 5: House service connection through a pressure tapping tee DAA to a drinking water line d 400 using the top loading method

FIG. 3: Expensive! Integration of a branch in a gas line d 500

FIG. 4: Venting spigot at a drinking water line d 450 using a top loading spigot saddle SA-TL

optimised fittings with regard to a construction site-ap-propriate 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 cov-ered saddle area is required. Specifically in the case of connections to existing pipelines, the bedding in the pipe-line 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 vac-uum (Figure 8). For this purpose, a circumferential seal-ing 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

The pipe surface is directly melted on and thus guaran-tees an enhanced material mixing of the two joining part-ners. The jointing area is thus enlarged and the mutual penetration of the molecule chains enhanced. An excel-lent fusion quality with high strength is achieved even un-der rough construction site conditions. Additional reliabil-ity is provided for by the size of the fusion area compared to the pressurised area. The extra-broad fusion zone re-sults in low specific tensions both under operating pres-sure and under the external loads resulting from the in-stallation 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

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FIG. 6: Top-load-ing 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. 8: Principle of spigot saddle SA-XL assembly with vacuum clamping technology

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)

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 com-bined 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 ac-cessories, but above all the space required in the pipe trench and the necessary access to the pipe are mini-mised. 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 pur-pose, a hole saw is used which is driven by a drilling ma-chine. 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 (Fig-ure 12) as well as the length of the tapping rod. The tap-ping 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 acces-sories and a lock fitting are required.

SPIGOT SADDLE AND T-PIECE: COMPARISON The integration of a branch line using a spigot saddle of-fers benefits from the economic and application-techni-cal 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 electro-fusion unit, fusion: 10 min

Cooling until tapping after end of fusion time: 10 min Pressurisation / pressure test after end of fusion time: 60 min

CONCLUSION Excellent experiences have been gained in numerous ar-eas of application with PE pipes in large dimensions. The advantages of the material and the jointing method, the

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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

FIG. 12: Full-port tapping of the pipe d 900 with flange outlet DN 150

electrofusion welding, lead to technical and economic op-timisation with regard to installation, operation and life.

The conical ring coupler technology, which was pre-sented in the first part of this technical report, revolution-ises the joining technology in the field of large pipes. The assembly process of the fitting is fundamentally simpli-fied when compared to traditional cylindrical couplers.

New fittings and innovative installation methods – as presented here taking the spigot saddle XL and the vac-uum 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!

Literature

[1] DVGW-W400„TechnicalRulesWaterDistribution(TRWW),Part2:Constructionandtestingofwaterdistributionfacilities,09/2004“

[2] DVGW-G472„madeofPE80,Pe100andPE-Xa–Erection“(2000-08)

[3] DVGWleafletGW335„Plasticspipingsystemsinthegasandwatersupply,requirementsandtesting-PartsA2,B2“

[4] Eckert,Robert:JoiningLargePEPipesinNoTimeatAll:Anewgenerationofelectrofusion,3Rinternation-al,issue3/2011

[5] Eckert,Robert:Electrofusionasmeanstoreducecostsinpipingconstruction?EnergieWasserPraxis,June2001

[6] Eckert,Robert:UseofelectrofusioninPEpipesoflargenominaldiametersofuptod710,3Rinternation-al,issue4-5/2004

[7] „FRIALEN®safetyfittings,assemblyinstructionforlayinglargeborepipes“,2006

[8] Eckert,Robert:Integration,shut-offandrepairtechnologyforPEpipesystems,PlasticsPipesXII,Mailand,2004

DIPL.-ING. ROBERT ECKERTFRIATECAG,MannheimTel.+49172-6425799E-Mail:robert.eckert@friatec.de

author

TABLE 2: Connection of a branch: Comparison of the methods

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Criterion / method Integration of T-piece Assembly of the spigot saddle

Underground work Large trench required, additional excavation for bypass might be necessary

Head access hole sufficient

Construction site safety, impairment of traffic

Corresponding to under-ground work

Corresponding to underground work

Restoration of surface Corresponding to under-ground work

Corresponding to underground work

De-commissioning, draining of piping

Required, possible safety cordoning

Commissioning under operating pressure possible

Time expense, duration of interruption of operation

High, because of draining the piping and integrating the T-pipe

Commissioning possible within one hour, possibly without interrupting the piping operation

Required equipment, tools

Standard Little accessories required: Vaccum equipment, drilling equipment

SAFE JOINING TECHNOLOGY ON A GRAND SCALEFRIALEN® XL Offprint

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