Plastic Pipelines Research Articles

Reef Climate Adaptation Research and Technology

The authors describe research into technological means for addressing two consequences of climate change for coral ocean acidity and increasing sea surface temperatures leading to coral bleaching. Technology for a multi- integrated response is proposed. Sea surface temperatures can be monitored via satellite and on-line telemetry. Technology for moderating sea surface temperature spikes is based on pumping deeper cool seawater over coral reefs. The technology proposed includes plastic collapsible pipelines that can be deployed like oil spill booms with flat disc pumps and renewable energy devices (tidal turbines) to power the pumps. The technology for counteracting increasing ocean acidity on coral reefs is based on the Accelerated Weathering of Limestone (AWL). It is proposed that an acceleration of the natural process that restores the carbon balance, can be realized using a modified electrolyzer powered by renewable energy. The AWL process sequesters CO₂ and produces H₂ while generating a buffer solution that increases reef pH and also provides alkalinity to feed reef and shellfish calcification. The AWL buffer solution will be distributed where required using the same renewable energy powered pumps and pipelines as used to mitigate sea surface temperature spikes. The AWL process will operate continuously but can be interrupted whenever the pumps and collapsible pipes are required to avoid potential coral thermal bleaching events. Dual use improves affordability.

Structural design and mechanical performance test of densely drilled glass fiber reinforced plastics pipelines

Densely drilled glass fiber reinforced plastic (GFRP) pipelines are thought to be of prosperous future in sand control in oilfield. However, due to the fact that the mechanical properties of the perforated GFRP pipelines are always lowered remarkably, some structural design work must be done. Several key factors, including the winding angle of the glass fibers, the mechanical properties of the matrix resin were considered carefully in advance. The tensile strength, compressive strength and the screw-crushing properties of the GFRP pipelines were measured subsequently. Most of the test results were coincided with what had been expected during structural design. The winding angle was proved to be an important factor in improving the mechanical performance of perforated GFRP pipelines. Mechanical property of the matrix resin was another important factor in determining the performance of the GFRP pipelines. The effect of the hole-size and distribution on the mechanical performance of the heavily perforated GFRP pipelines always depended on the winding angle and matrix resin. In the screw-crushing test, the GFRP pipelines showed to be easily destroyed by the slowly rotating drill head.

지하매설 플라스틱 배관의 누수지점 추정을 위한 창함수 비교 연구

ABSTRACT It is widely known that the leak locating of underground plastic pipelines is much more difficult than that of cast iron pipelines. The precision of the leak locating depends upon the speed of leak signal and the time delay estimation between the two sensors on the pipeline. In this paper, six different windowing filters are considered to improve the time delay estimation especially for the plastic pipelines. The time delay is usually estimated from the peak time of cross-correlation functions. The filtering windows including rectangle, Roth, Wiener, SCOT, PHAT and maximum likelihood are applied to derive the generalized cross-correlation function and compared each other. Experimental results for the actual plastic underground water supply pipeline show that the introduction of the filtering windows improved the precision of time delay estimation. Some window functions provide excellent leak locating capability for the plastic pipe of 98 m long, which is less than 1 % of the pipe lengths. Also a new probabilistic approach that the combinations of all results from each filtering window is suggested for the better leak locating.

Determining Operating Inlet Pressure Head Incorporating Uniformity Parameters for Multioutlet Plastic Pipelines

An important objective of a microirrigation system is to determine the proper operating inlet pressure head, ensuring the desired level of water application uniformity as well as the allowable pressure head variation along the multioutlet pipeline. This paper offers, simple, direct, but sufficiently accurate, relationships incorporating different microirrigation uniformity parameters, such as Christiansen uniformity coefficient, coefficient of variation of emitter discharge, and allowable pressure head variation, to determine the operating inlet pressure head (i.e., pressure head and outflow profiles) for multioutlet plastic pipelines. In this analysis some mathematical expressions were deduced to relate three uniformity parameters; then the operating inlet pressure head is simply reformulated by taking into account a multiplying factor α to the required average outlet pressure head, in terms of three uniformity parameters. Resulting, the influence of different uniform pipe slopes on the water application uniformity and the operating inlet pressure head for various emitter discharge exponents, was evaluated. In addition, to cover various design combinations an extensive comparison between the proposed equations and those of the previous studies was also presented. Examination of the results from this research indicated that, the performance of the proposed technique is sufficient in comparison to those of the recent analytical and numerical procedures.

Dense-Phase Pneumatic Conveying of Slush Ice Through Plastic Pipes

Ice is being used in certain deep mines to transport refrigeration to underground areas. Research has been carried out previously into the pipeline conveying characteristics of ice with air, but there remains a lack of knowledge about some aspects of this complex flow. Previous articles (Sheer, 1995; Sheer et al., 2001) have described experimental results on the pneumatic conveying of ice in particulate form (“hard” ice) through successive long horizontal and vertical sections of pipelines into mines. More recent research has been carried out to determine the conveying characteristics of “slush” ice that resembles wet snow, with an ice mass fraction range of 65–75%. Laboratory pneumatic conveying tests with slush ice were conducted through three horizontal plastic pipelines with inner diameters of 43, 54, and 69 mm, each pipeline being approximately 50 m long and including various bends. The tests yielded numerical and photographic data that were used to investigate the conveying characteristics of slush ice (including flow regime transition to plug flow and pressure gradients) and to compare them with the previous results for particulate ice. It was found that the conveying characteristics of the slush depend strongly on the water content. Correlations are proposed for multiphase friction factors.

Evaluating online data of water quality changes in a pilot drinking water distribution system with multivariate data exploration methods

The distribution of drinking water generates soft deposits and biofilms in the pipelines of distribution systems. Disturbances in water distribution can detach these deposits and biofilms and thus deteriorate the water quality. We studied the effects of simulated pressure shocks on the water quality with online analysers. The study was conducted with copper and composite plastic pipelines in a pilot distribution system. The online data gathered during the study was evaluated with Self-Organising Map (SOM) and Sammon's mapping, which are useful methods in exploring large amounts of multivariate data. The objective was to test the usefulness of these methods in pinpointing the abnormal water quality changes in the online data. The pressure shocks increased temporarily the number of particles, turbidity and electrical conductivity. SOM and Sammon's mapping were able to separate these situations from the normal data and thus make those visible. Therefore these methods make it possible to detect abrupt changes in water quality and thus to react rapidly to any disturbances in the system. These methods are useful in developing alert systems and predictive applications connected to online monitoring.

A probe for in situ, remote, detection of defects in buried plastic natural gas pipelines

Several techniques are available to determine the integrity of in situ metal pipeline but very little is available in the literature to determine the integrity of plastic pipelines. Since the decade of the 1970s much of the newly installed gas distribution and transmission lines in the United States are fabricated from polyethylene or other plastic. A probe has been developed to determine the in situ integrity of plastic natural gas pipelines that can be installed on a traversing mechanism (pig) to detect abnormalities in the walls of the plastic natural gas pipeline from the interior. This probe has its own internal power source and can be deployed into existing natural gas supply lines. Utilizing the capacitance parameter, the probe inspects the pipe for flaws and records the data internally which can be retrieved later for analysis.

Stress Analysis of the Aperture in Compound Pipeline by Fem

There is a cyclical aperture at a certain part of the fiberglass reinforced plastic compound pipeline with a stainless steel pipe as a liner, which becomes the weakness of the conduit. The field of stress and strain of the aperture was investigated using the nonliner finite element code Marc. The results of the finite element analysis showed that there were concentrations of stress and strain in the layer of stainless steel at the part of the pipeline where the aperture existed. The method to solve these problems was also discussed.

Estimates of microbial quality and concentration of copper in distributed drinking water are highly dependent on sampling strategy

The numbers of bacteria generally increase in distributed water. Often household pipelines or water fittings (e.g., taps) represent the most critical location for microbial growth in water distribution systems. According to the European Union drinking water directive, there should not be abnormal changes in the colony counts in water. We used a pilot distribution system to study the effects of water stagnation on drinking water microbial quality, concentration of copper and formation of biofilms with two commonly used pipeline materials in households; copper and plastic (polyethylene). Water stagnation for more than 4h significantly increased both the copper concentration and the number of bacteria in water. Heterotrophic plate counts were six times higher in PE pipes and ten times higher in copper pipes after 16h of stagnation than after only 40min stagnation. The increase in the heterotrophic plate counts was linear with time in both copper and plastic pipelines. In the distribution system, bacteria originated mainly from biofilms, because in laboratory tests with water, there was only minor growth of bacteria after 16h stagnation. Our study indicates that water stagnation in the distribution system clearly affects microbial numbers and the concentration of copper in water, and should be considered when planning the sampling strategy for drinking water quality control in distribution systems.

ADAP: A New Software for Automated Design and Structural Analysis of Plastic Pipelines

This publication contains a short description of a new software ADAP (Automated Design and Analysis of Pipelines)developed by the author for the structural analysis and design of buried as well as freely laid gravity and pressure piping systems. It includes an overview of the design criteria, design procedure and the scheme for stress, deformation, and stability analysis. The software is based on the dimensioning guidelines including prEN1295; it goes, however, further in the sense that it includes the length effects. The results of ADAP include short-term and long-term stresses, strains, deformations, buckling loads, axial forces, safety factors, and pipe dimensions. Additionally, the dimensions of the pipe corresponding to desired safety factors can be determined. The worked example deals with the short-term and long-term stress, deformation and stability analysis of a PE-HD pressure pipeline.

Electrostatic ignition hazards arising from fuel flow in plastic pipelines

The use of electrically insulating synthetic materials, such as plastics, for fuel pipelines and other fuel handling components is now becoming widespread. In the case of buried or underground pipelines in filling station forecourts the use of these materials offers superior corrosion resistance and increased longevity. This in turn reduces the risk of pollution due to fuel leakage. It is well reported that the flow of fuel under certain conditions in metal pipes can produce significant levels of electrostatic charge on the fuel. Little work, however, has been undertaken on plastic pipe where charge can accumulate at the fuel/pipe wall interface. This paper reports on tests performed on a full-scale, high-density, polyethylene pipework system. During the tests, an iso-octane/toluene fuel mix of controlled and known electrical conductivity was transferred through the system at varying flow rates. Both buried and free-standing pipeline configurations were simulated. A number of test runs were performed yielding considerable data relating to the resultant electrostatic activity including electrostatic potential, the nature and location of electrostatic discharges and the discharge energy. The influence of components such as in-line valves and couplings, which have a metallic component, are also evaluated. The extensive data resulting from this study are presented graphically. The paper concludes with an analytical section and draws important conclusions with regard to the parameters influencing the degree of ignition hazard present.

The structural performance of flexible pipe for landfill drainage

The structural performance of perforated plastic pipelines used for landfill drainage is difficult to predict. This paper aims to describe their structural action on the basis of field measurements, and thereby make recommendations for their design and installation. The key requirements for structural support of buried plastic pipes and development of stable arching are described for both embankment and trench conditions. The most important is the relative stiffness of the pipe surround, which is directly related to the degree of confinement. The ‘ground conditions’ in a landfill, however, are far removed from those of embankment fill, the variable nature of the waste resulting in a complex loading pattern and variable degrees of local confinement. Field measurements of pipes buried in different surround conditions in a landfill as the waste progressively increases in height are reported and compared with laboratory results. The deformed shape in the smaller gravel surrounds was found to differ from that in simulated laboratory tests, although classical theory was found to predict baseline pipe deformations reasonably well. Landfilling practice close to the gravel mounds was found to be critical to pipe performance.

堆積層上の粒子群の流動について

Contrary to the most investigators' opinions that the deposit regime is uneconomical, some papers have reported this regime to be not necessarily uneconomic since the power requirement may decrease for velocities below the limit deposit velocity. Also, it is said that in all applications of industrial significance the system should be designed to prevent occurrence of this unsafe region because there is imminent danger of pipe blockage. Nevertheless, for the slurry pipeline system transporting coarse solid particles and involving difficulties in controling operational variables rigorously such as hydraulic dredging or hydraulic conveying of run-of-mine coal, it is inevitable for some or all of solids to deposit temporarily on the bottom of the pipe.On these bases there is an immediate need for relationships to use in estimating both the bed thicknesses and the hydraulic gradients under the flow conditions in the deposit regime.This paper presents results of investigations of design methods in this regime. Experiments were conducted to support the theoretical modeling effort for the particle size range 1.71-3.10 mm using a 25.9mm (ID) transparent plastic pipeline, with total length of approximately 10 m, mounted on the frame horizontally.The correlation of experimental data has shown that the ratio hr of the bed thickness to the pipe diameter D and the hydraulic gradient im of slurry flow may be determined from following equations if the functions of f1 (Cv) and f2 (Cv) are given experimentally:_??_in which: Va=apparent mean velocity of slurry flow; g=gravitational constant; Cv=delivered volumetric concentration of solids; v=kinematic viscosity of water; R, R0=hydraulic radii of the free flow section above the bed and of the pipe; Vt=terminal settling velocity of single particle;δ=specific gravity of solids.

Spectral analysis of wall-pressure fluctuations in turbulent two-phase flow

A closed two-phase flow loop system was designed and constructed to measure the spectral characteristics of wall pressure such as rms values, power spectral density, and axial-lateral cross correlations. In this loop, the two-phase flow entered a straight run of smooth plastic pipeline (PVC) having an inside diameter of 20.32 cm (8 in.), achieving at the test section a maximum Reynolds number in the order of 2×106 on a liquid basis. Measurements of the wall-pressure fluctuations in a turbulent dispersed two-phase flow were conducted using miniature semiconductor pressure transducers mounted flush with the internal surface of the rigid thick-walled metal pipe working test section. Narrow-band spatial correlations were obtained over different center band frequencies ranging from 56.22–891.24 Hz and flow velocities at liquid Reynold’s number of 0.819×106 to 2.0878×106. Lower values of the mixture velocity and the intensity of the pressure fluctuations were observed for high void fraction flows. In general, two-phase flow wall-pressure fluctuations were characterized by low-amplitude frequency spectra. Axial and lateral two-phase flow correlations have shown dependence upon the flow quality (volumetric mixing ratio) and Strouhal number. Two-phase flow wall-pressure field convection showed an increase at higher two-phase flow mixing ratio. The lateral microscale of turbulence was found to be approximately five times that of the axial direction.

THE INFLUENCE OF WAVES ON THE HYDRAULICS OF SEA OUTFALLS

Most of the larger cities in Denmark are located near the sea. About 60% of the sewage is therefore discharged through sea outfalls. Most of these sea outfalls were built in the seventies. In most cases a plastic pipeline were used, and the pipeline was ballasted with armoured concrete blocks and burried in a trench 1 - 2 m underneath the seabottom. To give the necessary initial dilution a diffusor with one or several contracted, horizontal outlets ends the pipeline. The Danish coasts are in general shallow and exposed to waves. The littoral sanddrift is considerably and the sea outfalls need to cross one or more bars. The diffusors are often placed outside the bars, but nevertheless sediment transport can occur around the diffusor. Figure 1 gives some typical data for Danish sea outfalls.

Plastic pipeline fittings

Plastic pipeline fittings

Plastic pipeline valves

Plastic pipeline valves

Plastic Pipelines for Livestock Water in Northwest Nebraska

Plastic Pipelines for Livestock Water in Northwest Nebraska