WET News

16 WET NEWS MAY 2014 The pipe eating head approaching the end of the replacement run. Note the fracturing original pipe in the foreground Malvern, Worcs WR14 1JJ, UK Tel: +44 (0) 1684 891 371 info@pulsar-pm.com www.pulsar-pm.com FlowPulse Flow Monitor Designed to reliably monitor flowrates of liquids and slurries to 4m/s in pipes to 1m dia and 20mm wall thickness. Non invasive. Clamps onto outside of pipe. Patent pending DSP technology ensures reliability. l PC configuration l Remote set up and display option l Simple pipe strap fixing l ATEX Ex m pending l 4-20mA output/ Modbus and relay alarm FREE SITE TRIAL Contact us today for information A very large auger rig would probably have accomplished the drive but with weights in excess of 3,000kg and large excava- tions required, this option was also discounted. Struggled The team opted to utilise an innovative combined auger bor- ing rig and pipe burst rig assem- bly to complete a 'pipe eating' replacement technique. At one side of the run, where the exist- ing pipe ran at 3.5m deep, a Per- forator PBA150 auger boring sys- tem with 150t of thrust was used. At the reception end of the run there would be a Hammer- head 100t capacity HB100 pipe bursting rig, weighing just 1.3t, provided by U Mole. The maximum size of exca- vator that could access the site was a small 14t unit, which in the ground conditions some- times struggled to achieve its operational requirements. The process of bursting the old pipe and replacing it with the new larger pipe is 'Assisted Pipe Eating'. With both the auger boring unit and the burst- ing rig positioned, a series of upliˆ pulling rods were passed through the existing pipe to con- nect the machines. The pipe- eating head was attached to the lead pipe of the jacking rig which also had a cutting ring on the front edge to aid passage of this pipe into the ground. The jacked and pulled pipe was a 762mm diameter steel pipe, which was to act as a permanent sleeve. With the new pipe and burst- ing head positioned, the pulling rods from the burster rig were attached to the front-end of the pipe eating head mandrel. Working together to provide up to 250t of force at the pipe eating head, the Perforator unit jacked the assembly head forward whilst at the same time the burster rig pulled the assembly towards its operating pit. Not only did this provide suf- ficient thrust to the bursting head to fracture the old pipe but also enough pressure to ensure the new pipe passed into the ground effectively. Simultane- ously to the push / pull opera- tion, the displaced earth and fragments of the broken pipe were transferred back down the permanent steel sleeve by the auger spiral and removed to the surface by skips from the jack- ing pit, preventing excessive compacting of earth at the upsizing head. The pulling force from the HB100 also ensured that the pipe eating head remained on the same line and level as that of the old pipe. The steel carrier pipe was extended at the end of each push / pull stage by weld- ing on a new 3m long section at the jacking rig end. During the pipe eating works, both machines had to work hard with instances throughout the opera- tion where the HB100 burster rig operated at its maximum ton- nage capacity. Towards the end of the replacement run, as the pipe eating head approached the burster rig position, jacking was paused so that the thrust wall of the burster could be removed. The burster rig was discon- nected and the final few meters of the installation was com- pleted using the auger rig alone so that the pipe eating head and the lead edge of the sleeve pipe could be extended into the burster pit. Waste control The replacement works were successfully completed and the remaining spoil and old, now broken, pipe cleaned from the steel carrier pipe. A 600mm diameter twin wall PE sewer pipe was inserted through the sleeve pipe and connected at either end to the remainder of the sewer network at both new and existing manholes. One of the biggest timing dif- ficulties came from the lack of storage space at the pipe jacking pit which meant that each indi- vidual 3m steel pipe section had to be brought in from off-site to be available for installation in the jacking frame just as it was needed. The route through the woodland made this a difficult journey with each pipe section. The use of this innovative trenchless technique also meant that waste control was more easily managed with the only waste produced being that cre- ated to dig the operations pits and that removed from the sleeve pipe by the auger string. The trenchless option also meant that the carbon footprint of the works was also very much reduced as compared to poten- tial alternative installation methods. Peter Taylor, managing direc- tor of Pipeline Drillers, says: "This was not an easy project by any means. The logistics bor- dered on nightmarish with lim- its on equipment size, site stor- age, transportation and precise timing. However, our crew worked extremely well with George Leslie's workforce to safely and efficiently complete what was something of a unique project under challenging cir- cumstances in an excellent timeframe." Tel 01234 750924 email enquiries@stonbury.co.uk www.stonbury.com STONBURY 31 YEARS AS MARKET LEADERS IN THE REFURBISHMENT OF WATER RETAINING STRUCTURES & ASSOCIATED ASSETS RESERVOIR & WATER TOWER REFURB - SEWAGE TREATMENT WORKS, PIPE BRIDGE & AQUEDUCT REFURB - STEEL & CONCRETE TANKS & VESSELS REFURB/ REPLACEMENT - SPECIALIST COATINGS - WATERPROOFING - INSPECTION CORROSION PROTECTION - CLEAN & CHLORINATION - CIVIL ENGINEERING - SECURITY WORKS INC LPC4 ACCESS COVERS, LADDERS, HANDRAILS & WALKWAYS concrete steel clean water civil engineering waste water SHARE YOUR OPINION... yoursaywn@fav-house.com Eta keeps the world on the move Etanorm Etaline Our Eta pump family keeps the world on the move. And there are plenty of big reasons: the highly efficient top-class hydraulic system. Dozens of sizes, materials and drives in almost any combination. And service that puts rivals in the shade. After millions of great pumps, the new generation is here. 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