- A new Manufacturing Technology for Large Diameter Polyethylene Pipe Fittings
Author(s) : Aboutorabi, Bowman 1988 Bath
A rwte for the marufaoture of large diameter polyethylene pipe fittings, based on a unique combination of mtommld- ing and irradiation, is pmposed. The method requires a low investment in twling but can give rise to pressure rated, mulded fittings, capable of being fusion jointed to polyethylene pipe. This...
- A Novel Process for Lining Pipes with Polyolefins
Author(s) : Butters, Mistry 1988 Bath
Steel and other pipes can be successfully lined with polyolefins by means of a novel process involving the draw down and reversion of extruded polyolefin pipe. The process employs a combination of standard and simple technology and relies upon a tailor made polymer designed to provide uniform draw d m without...
- Characterisation of Blue MDPE Water Pipe
Author(s) : Mallison, Gwynn 1988 Bath
BP Chemicals International together with Stewarts and Lloyds Plastics have provided Rigidex PC 002-50 R968 pipes for the WRC project studying rapid fracture, fatigue and ageing characteristics of MDPE.The production and characterisation of the pipes and compound are discussed. In particular the residual stress,...
- Deformations in Buried Flexible Pipes
Author(s) : Alferink, Wolters 1988 Bath
Knowledge about the behaviour of buried flexible pipes has become more and more important in the Netherlands. It serves several objectives, for instance, to evaluate stress corrosion, installation techniques and new materials, as well as drawing up new design codes and test procedures for pipes and components. This...
- Degradation of Plastics Pipes in a Tropical Climate
Author(s) : Quershi, Hamid, Amin,Maadhah 1988 Bath
The degradation of plastic pipes in the domestic, industrial, and general purpose applications in Saudi Arabia are discussed. It is shown that the higher rate of failure of pipes exposed to natural weather results from elevated temperatures, and very high dose of total solar radiation received in the region. In...
- Electrofusion - A new System
Author(s) : Walton, van Houten 1988 Bath
Electrofusion fittings have now been widely accepted within the European Gas Industry for jointing polyethylene pipe. with a high potential demand for electrofusion couplers, Wavin applied its plastics process knowledge to develop an efficient and cost effective co-extrusion manufacturing technique. In this method a...
- Evaluation of Aged Plastics Pipes Used in Natural Gas Distribution Systems
Author(s) : Duvall, Nylander, Broutman 1988 Bath
Thermoplastic gas distribution piping has been utilized in the United States for over 25 years. However, there is little data available on how such materials age in a service environment and how such aging might affect future performance. In this program, polyethylene pipe samples that were removed from actual gas...
- Extrapolation of Stress Rupture Data De Putter
Author(s) : De Putter 1988 Bath
New calculation method for long term Hydrostatic Strength is explained and demonstrated by data on PVC, CPVC and PE. Basis is also given in ISO DTR 9080.2.Pipes and fittings of thermoplastic materials are used in all types of applications in the water, gas, sewer and other industrial applications where a long life is...
- Extrusion Technology for Large Diameter Polyolefin Pipes
Author(s) : Limper 1988 Bath
This Paper sums up the possibilities of cost reduction, especially for large diameter pipes, by automation of the extrusion line. Beneath the overall cost structure, steps such as gravimetric feed, constant meterweight control, mechanical or thermal centering and data acquisition are discussed. It is pointed out where...
- Factors Controlling the Lifetimes of Polyethylene Pipes in the Slit Mode Failure Regime
Author(s) : Wright, Bowman 1988 Bath
Studies are reported on the performance of pipes produced fmm selected blends of polyethylene materials. The pipes were tested at a single temperature of 80°C and at irternal pressures designed to induce slit-mode failure. It is shown that blending the wrong polyethylene resins can substantially reduce performance of...
- Flexible Pipe Design and Installation
Author(s) : Jones 1988 Bath
T h e paper provides a broad averviev in relation to the design and installation o f buried flexible plastic pipes from a current UK perspective. Issues relating to the interrelation between materials properties, structural design and installation aspects are discussed.
- Fracture of GRP Pipe bends under a Variety of Loads
Author(s) : Myler, Kitching 1988 Bath
Six right angled smooth pipe bends of G W consisting of E-glass reinforcement of chopped strand mat (CSM) vith polyester resin have been tested to destruction under various load conditions including internal pressure only, in-plane flexure only, and in-plane flexure combined with pressure. The pipe diameters were all...
- Gravimetric Compound Throughput Recording as the Key to Automatization of the Extrusion
Author(s) : Neumann 1988 Bath
After having overcome the initial difficulties of this new technology, gravimetric compound throughput recording with weight per metre control has become the basic and standard system for the automatization of extrusion lines. This system is especially suitable for subsequent in stallation, it can be connected to the...
- Mechanical Behaviour of Composite Thermoplastic Pipes
Author(s) : LeHunt 1988 Bath
The theory and experimental behaviour of solid skin/foam core PVC composite pipes is discussed.Experimental load testing for periods in excess of 10,000 hours has been conducted and the influence of the ratio of skin/core sections examined within the programme to evaluate long term design properties for external...
- Medium Density Pipe Materials for Elevated Temperatures
Author(s) : Thoresson 1988 Bath
The development of a new generation of polyethy lene pipe materials for elevated temperatures has been going on at Neste Polyeten for more than 10 years. A new MDPE grade can be used up to 47 °C at a design stress of 5,0 MPa and a life-time of 50 years. A further development Will increase the temperature to 55 60...
- Physical Ageing of Buried PVC Sewer Pipes as Affecting their Long Term Behaviour
Author(s) : Janson 1988 Bath
The investigation has indicated that deflected uPVC pipes are subjected to a physical aging process, which gives rise to a lower rate of decrease in the E-modulus than has previously been assumed. Based upon these findings the long term ring stiffness of PVC sewer pipes is determined. Concerning the bending strength...
- Plastics in Sewer Renovation
Author(s) : Rice 1988 Bath
The UK has the highest proportion of the population connected to a public sewer in comparison with any other country. Couple this with the population density on this island, the fact that some of these sewers are aver 180 years old, lie mainly beneath highways...
- Prediction of Stiffness of Foamed Pipe Systems
Author(s) : Moore, Stephenson 1988 Bath
A model is established for the calculation of flexural rigidity (EII of pipe sections that contain a solid skin - foamed core - solid skin structure. Stiffness of t h e pipe can be calculated from (EII. The model accommodates different and similar materials in the skin and the core, a range of section dimensions...
- Rapid Crack Propagation in Hydrostatically Pressurized 250 mm Polyethylene Pipe
Author(s) : Greig 1988 Bath
The catastrophic phenomenon of rapid crack propagation in 250 mm diameter polyethylene pipes has been investigated at a full scale test facility. Tests at +3°C were conducted with pipes, either completely fully of water or containing a small percentage of air. The safe, maximum pressures were measured. Rapid crack...
- Residual Stress in Large Diameter MDPE Water Pipe
Author(s) : Beech, Burley, Bunn 1988 Bath
Production of plastics pipes by conventional extrusion results in 'frozen i n r stress in the pipe wall, termed residual stress. Techniques have been established for assessina the levels of ~, this stress and relating to extrusion coaling conditions by mathematical modelling. However, the effects on long term...
- Ring Stiffness by Long-Term Creep and Relaxation Tests of Rib-Reinforced uPVC Sewer Pipes
Author(s) : Koski 1988 Bath
The ring stiffness of a new design ribreinforced uPVC sewer pipe is studied. Creep measurement for 1000 h gives a reasonable first approximate of long-term stiffness. Because of the specific creep behaviour of uPVC, the measurement for 10,000 h gives a higher estimated stiffness. Relaxation results on new pipes...
- The Abrasion Resistance of Polymers Used in Slurry Transport Systems
Author(s) : Lowe, Marshall 1988 Bath
A Rotating Pipe Drum Test has been developed to assess the abrasion performance of plastics pipes to an extpnt where most test variables are understood. The procedure involves the rotation of relatively short pipe lcngths containing slurry on a conventional bail mlll. In the rest, the pipe surface repeatedly passes...
- The Behaviour of a Multilayered GRP Pipe when Subject to Local Attachment and Fluid Loading
Author(s) : Tooth, Banks, Wilson 1988 Bath
An outline is given of the main processes employed for the manufacture of multilayered GRP pipes intended for the conveyancing of both water and contaminated fluids, where high strength and light weight lead to cost and/or transportation benefits. The analysis presented, which is based on Sanders’ thin shell theory...
- The Butt Fusion Jointing Process - Fundamental Aspects
Author(s) : Watson 1988 Bath
This paper reports a study of the burr fusion process as used for medium density polyethylene gas and water pipe. Investigations of the process mechanisms, the response of the material being welded and mechanical rest data are discussed. Polyethylene pipe is widely used for low pressure gas and water distribution...
- The Characterisation and Performance of UPVC Pressure Pipes
Author(s) : Moore, Stephenson, Tagger 1988 Bath
A number of UPVC pressure pipes .of different sizes and classes, have been characterised in materials. Long term testing was performed on specimens under a range of loading regimes, including hydrostatic burst testing, long term fracture toughness testing and dynamic fatigue. In all instances the behaviour...
- The Correlation of Fast Fracture Resistance of Polyethylene with Impact Toughness
Author(s) : Marshall, Birch-Kisbenyi, Youd 1988 Bath
A complete analysis of the Charpy impact system has been made to relate measurements of impact toughness to the geometry of samples. Using data obtained on pipe grade polyethylenes, Gc values at 20°C and 3°C have been found to correlate wel! with measurements of resistance to fast fracture in pressurised pipe...
- The Effect of CaCO3 Fillers on Processing and Mechanical Properties of UPVC Pipes
Author(s) : Gilbert, Higgs,Hancock 1988 Bath
The effect of the particle size of natural calcium carbonate fillers on fusion behav ,LI! during processing, and subsequent mechanical properties of UPVC pipes has been investigated. Fine fillers were shown to aid fusion, while coarser particles hindered the process. Adequate tensile and impact strengths depended o n...
- The Failure of Polyethylene Gas Pipe Materials by Slow Crack Growth
Author(s) : Brown, Lu 1988 Bath
Two of the pipe resins that are commonly used in the USA are compared with respect to their relative life times. The improvement in the performances of the currently used materials compared to the older material from the same producer have been measured. T h e 1ahoratoi-Y conditions for producing brittle failure in...
- The Fatigue Behaviour of Medium Density Polyethylene Pipe Systems
Author(s) : Bowman 1988 Bath
Elevated teqerature fatigue of MDPE pipe system showed socket and electrofusion fittings had similar fatigue lifetimes, while butt jointed pipes failed at repmducibly lower lifetimes. Extrapolatims to 2O'C preserved the raking in joint performance, although combined creep ad fatigre tests showed pure fatigue...
- The Long Term Behaviour of Buried uPVC Sewer Pipe
Author(s) : Walton, Elzink 1988 Bath
One of the main reasons that plastics have not found more extensive use in non pressure sewer schemes has been concern about the long term deformation characteristics of the pipeline. In order to investigate this phenomenon the flexural behaviour of u W C sewer pipes installed in Western European countries, including...
- The Long Term Performance of Plastics Pipes
Author(s) : Boon 1988 Bath
Since the early Eighties the UK Watec Industry has witnessed a significant growth in the use of MDPE pipe. To ensure confidence in the use of the material and to generate confidence in PVC-U pipes, a collaborative project between the Water Industry and the manufacturers, was undertaken. The aims of the...
- The Possibility of Assessing the Long Term Performance of PE Pipes Using a Quality Control Fatigue Test
Author(s) : Greig, Lawrence 1988 Bath
Hydrostatic s~ress rupture testing at 80°C of polyethylene gas pipe currently takes sver 1000 ho7.1rs to determine its good stress cracking performance. This is excessively long for quailty control purposes so a rapid rest is being developed using fatigue pressurlsac. :on, 2gajn on notched...
- The Production and Application of Bioriented PVC Pipe
Author(s) : Meijering 1988 Bath
A process has been developed to produce bioriented PVC pipes. Due to the biorientation process, the long term strength has been increased by a factor 2. This means that the design stress of bioriented PVC pipes can be twice of normal extruded PVC pipe. The long term stiffness Of the bioriented pipe has been increased...
- The Renovation of Trunk Mains and Distribution Pipes in NWWA by Cold Drawn Swage Lining with MDPE
Author(s) : Young, Thomas, Marshall 1988 Bath
Within the Water Industry in England and Wales, there is an estimated length of 295,000 km of water main, much of which was laid in unlined cast iron prior to 1940. Subsequently, asbestos cement, UPVC and cement lined cast/ductile iron has been uscd. It is kn-that a substantial number of...
- Thin-Walled Thermoplastics Pipes
Author(s) : Jaervenkylae 1988 Bath
Stressed skin and rib-reinforced shell structures optimize plastics pipe performance.Computation of engineered pipes 1S easy as they can be substituted for by orthotropic pipes having the Same rigidity characteristics.The flexible pipe theory lends itself very well to the concept of thin walled piastics pipes...
- Corrugated Pipe Production Latest Developments
Author(s) : Rahn 1988 Bath
- Developing an ISO Test-Method for rapid evaluation of ESCR in Polyethylene Pipes
Author(s) : Margalit 1988 Bath
- In Field Quality Control of Fusion Jointing Methods
Author(s) : Stafford, Maine 1988 Bath
- Material for Crosslinked Polyethylene Pipes
Author(s) : Lind 1988 Bath
- Recent Developments in the Design of Underground Plastics Pipes
Author(s) : Molin 1988 Bath