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‘Joint initiative’ is brought to the SA market by DPI Plastics

DPI Plastics will be launching two exclusive, state-of-the-art pipe joint coupling products at the upcoming Electra Mining and IMESA shows respectively. 

(Sept 2010) A revolutionary breakthrough in pipe joint technology will be introduced to the South African market by DPI Plastics, a leading manufacturer of water reticulation, drainage and pipe-fitting systems.

The groundbreaking Durolok internal restraint joint for PVC piping, manufactured in the USA, differs from traditional spline-locked internal restraint systems, as it comes fitted with a steel support ring, as well as serrated grip-ring and a rubber seal integrally formed into the pipe socket – in order to maintain the economic effectiveness of socket and spigot-type joints.

The product, which is fitted to 110 mm, 160 mm and 200 mm PVC pressure pipes, conforms to internationally-recognised American Society for Testing and Materials (ASTM) F1674 specifications that incorporates a 1-million pressure-cycle test, and also carries the SABS approval when used in pipe systems carrying the SANS 966 and SANS 791 marks of approval.

DPI Plastics product manager Mike De Villiers notes that the Durolok internal restraint joint would be ideally-suited to the local horizontal directional and trenchless drilling market, where it can serve as a cost-effective replacement  for the industry-standard range of butt-welded High Density Polyethylene (HDPE) piping.

“PVC pipe fitted with the Durolok restraint joint has many advantages over HDPE pipe in trenchless applications. In terms of flow characteristics, the thinner walls of PVC pipe allow greater delivery of water for a similar size of HDPE pipe,” De Villiers explains. “Durolok’s state-of-the-art cartridge installation means that PVC pipes do not have to be strung out and pre-jointed into continuous strings for installation. Each length may be jointed in a short access pit, as required during the ‘pull’, with no need for specialised jointing tools. What’s more, no time will be lost waiting for the butt welds to cool down, as is the case for HDPE pipe.”

When compared to external restraint joints, De Villiers points out that Durolok technology keeps corrosion to a minimum, owing to the fact that the restraint components are fully resin-coated and fitted internally in the pipe socket and; therefore, do not come into contact with the fluids being transported in the pipe or the surrounding soil.

De Villiers also notes that Durolok’s easy installation process means that contractors save both time and labour, as no additional tools are required to fit and tighten the restraint device. “The internal restraint system eliminates the need for trained operators to fit the restraint device, and cuts out the inherent risk of human errors, which include over-tightening of clamps and tie bars,” he explains.

De Villiers admits that it will be a challenge changing the mindset of local contractors and engineers; however, he is confident that Durolok will make a successful entry into the South African market. “Durolok has enjoyed global success, and I am confident that with all the pipe rehabilitation work currently being undertaken in South Africa, it will be seen as a viable and cost-effective solution for the civil industry,” he concludes.

Another innovative product being introduced to the South African market by DPI Plastics is the patented Ultralok PVC-M coupling for the jointing of plain-ended pipes, developed in-house by DPI. The first-of-its-kind product, which is designed for applications of up to 16 bar pressure, is being aimed at both the civil and mining industries. 

“The Ultralok PVC-M coupling and components are fully-protected against corrosion. What’s more, the design mechanism of Ultralok is different to any other product on the market in terms of its robustness and gripping nature. The clamping mechanism is unique because it is manufactured from high-impact PVC, and comes with a unique pressure-enhancing rubber seal,” explains DPI product manager for mining and building, Allen Behrendt. “As the pressure increases, the design of the seal facilitates a distributed type of load on the seal; thereby, alleviating the load on the body of the coupling.”

Behrendt notes that DPI Plastics currently has a 105 mm prototype - specifically-designed for the mining industry. The product meets numerous high-pressure requirements, and has successfully met the following test criteria for SANS 1283 Specification:

-       one hour test at 54,50 bar

-       the ten-hour test at 50,60 bar

-       the one hundred hour test at 45,50 bar

-       the one thousand hour test at 16 bar x 600C water temp

-       the pipe/joint deflection test

“We are confident that Ultralok will have a bright future in South Africa. Once we have launched the prototype, we will look at expanding into the polyethylene market too,” explains Behrendt. “The design concept of this coupling will facilitate itself for additional markets that will include civil, industrial and agricultural applications.”

Once the prototype is launched, further Ultralok couplings will be introduced to include sizes 110 mm, 155 mm, 160 mm, 200 mm and 210 mm, for the civil and mining markets, Behrendt concludes.

Both the Durolok and Ultralok range of products will be on display at the 2010 Electra Mining Show, being held at the NASREC expo centre from 4-8 October, and at the 2010 IMESA Show in East London, from 27-29 October.

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