Internal Surface Of Pipe Research Articles

Design of a New In-Pipe Inspection Robot

Basically robots are designed in such way that they remove human intervention from labour intensive and hazardous work environment, sometimes they are also used to explore inaccessible work places which are generally impossible to access by humans. The inspection of pipe comes in same category because they carry toxic chemicals, fluids and most of the time has small internal diameter or bends which become inaccessible to human. The complex internal geometry and hazard content constraints of pipes demand robots for inspection of such pipes in order to check corrosion level of pipe, recovery of usable parts from pipe interior, sampling of sludge and scale formation on pipe internal surface etc. Several designs of In-pipe inspection robots (IPIR) have been proposed in the literature to solve the problems related with inspection of these complicated internal geometries. Designing of an in-pipe inspection robot (IPIR) is a difficult task and hence the designer must take care of the design issues like Mobility, Steer ability, Turning radius, Size and shape adaptability, Online adaptability, Flexibility, Stability, Autonomous operation and obstacle avoidance, Efficiency at uneven surface, Safe operation, Material selection, Type of task to be performed inside the pipe, Number of actuators, Operation in active pipe line, Retrieval of robot, User friendly navigation and control system, Range of operation, Quantitative analysis of defects inside the pipe. Based on above, this research work presents investigations into design issues pertaining to development of In-pipe inspection robotics and proposes a new model of an In-pipe inspection robot to overcome some critical design issues. This proposed model is a screw drive type wall press adaptable wheeled In-pipe inspection robot. It is able to move through vertical, horizontal pipes and it can easily pass through elbow of a pipe line. This model comprises of three modules- rotor, stator and control unit. The Rotor module has three wheels mounted on the outer periphery with a helix angle of 15°. Wheels of rotor follow the helical path on the internal surface of pipe line and move in the longitudinal direction inside the pipe.A geared DC motor of 200RPM is connected to rotor by a flexible sleeve coupling. Due to its flexibility motor can transmit torque to rotor even in case of minor misalignments and can easily be stopped at any point of journey inside the vertical or horizontal pipeline, thereby eliminating the need of braking system to achieve stability. Stator module is the housing of motor and it contains three spring loaded wheels on the outer periphery. Control Module of robot consist battery and wireless control unit. Spring loaded wheels of rotor and stator provide it shape adaptability and enhance friction between wheels and pipe interior.

Эффективные методы прочистки трубопроводов

The article contains the analysis of the efficient methods of piping cleaning of water supply and sanitation systems. Special attention is paid to the ice cleaning method, in course of which biological foil and various mineral and organic deposits are removed due to the ice crust buildup on the inner surface of water supply and drainage pipes. These impurities are responsible for the deterioration of the organoleptic properties of the transported drinking water or narrowing cross-section of drainage pipes. The co-authors emphasize that the use of ice compared to other methods of pipe cleaning has a number of advantages due to the relative simplicity and cheapness of the process, economical efficiency and lack of environmental risk. The equipment for performing ice cleaning is presented, its technological options, terms of cleansing operations, as well as the volumes of disposed pollution per unit length of the water supply and drainage pipelines. It is noted that ice cleaning requires careful planning in the process of cooking ice and in the process of its supply in the pipe. There are specific requirements to its quality. In particular, when you clean drinking water system the ice applied should be hygienically clean and meet sanitary requirements.In pilot projects, in particular, quantitative and qualitative analysis of sediments adsorbed by ice is conducted, as well as temperature and the duration of the process. The degree of pollution of the pipeline was estimated by the volume of the remote sediment on 1 km of pipeline. Cleaning pipelines using ice can be considered one of the methods of trenchless technologies, being a significant alternative to traditional methods of cleaning the pipes. The method can be applied in urban pipeline systems of drinking water supply for the diameters of 100—600 mm, and also to diversion collectors. In the world today 450 km of pipelines are subject to ice cleaning method.Ice cleaning method is simple, quick, effective, economical and environmentally safe compared to other methods, allowing to remove the growths of biofilms and other pollution and maintain the hydraulic performance of pipeline operation at the expense of drawing on the internal surface of pipes of ice crust.

Assessment of multi-objective optimization for nondestructive evaluation of damage in structural components

A multi-objective optimization-based computational approach to nondestructive evaluation of damage in structural components, and more generally in solid continua, is discussed and numerically evaluated. The multi-objective approach provides a substantial improvement in the capabilities to traverse the optimization search space to minimize the measurement error and produce accurate damage estimates. Through simulated test problems based on the characterization of damage in structural steel components, including internal pipe surface geometry as well as material loss within a plate structure utilizing steady-state dynamic measurements of outer surface displacement, a multi-objective genetic algorithm optimization approach is shown to provide substantial computational improvement over single-objective strategies. The multi-objective approach consistently and efficiently produces more accurate characterization results in contrast to equivalent single-objective strategies. More importantly, the multi-objective approach is shown to exhibit consistently better tolerance to test measurement noise and measurement sparsity. Moreover, the multi-objective strategy was found to provide improved diversity in the solution estimates for ill-posed problems, which is an important step leading to insight into the necessary changes to the testing or parameterization to subsequently produce more accurate and unique solutions to such inverse characterization problems.

High Frequency Guided Wave for Detection and Depth Sizing of Concave Defects on Internal Surface of Pipes

It is time-consuming to inspect long pipes in power generation facilities using conventional ultrasonic testing techniques because scanning is necessary. Ultrasonic guided waves potentially provide an attractive solution to this problem because they can propagate several meters once they are excited at one location on the structure. This paper addresses the propagation of high frequency guided wave in a plate and in a pipe, and its interaction with localized wall-thinning on internal surface due to corrosion or erosion. Guided waves were generated in a stainless steel plate and a carbon steel pipe with thickness of 10mm, respectively. The pipe whose diameter is 318 mm contains artificial concave defects with different sizes in order to simulate localized wall-thinning on internal surface. A 2D finite element model was used to simulate wave propagation within the plate, and the characteristics of guided waves were also studied using a 2 MHz conventional transducer. The high frequency guided waves were explored for their capability of detecting and sizing defects.

Influence of friction on the surface quality of cold-deformed pipe

The influence of the basic parameters of cold Pilger rolling—including the lubricant viscosity, the extension, number of double passes in the cell, the mandrel taper, and mechanical properties of the rolled metal—on the thickness of the lubricant layer between the internal pipe surface and the mandrel is considered. Experimental data for the contact surface area are presented. The conditions corresponding to improved surface quality of the pipe are identified.

A simple approach to assessing copper pitting corrosion tendencies and developing control strategies

Localized corrosion of copper premise plumbing in drinking water distribution systems can lead to pinhole leaks, which are a growing problem for many homeowners. Despite the fact that water quality is an important factor associated with localized copper corrosion, good approaches for predicting the tendency of water to support localized corrosion and for assessing water treatment options to address problems are not available. The objective of this research was to determine the effectiveness of a simple pipe loop system, installed in a drinking water distribution system, in predicting localized copper corrosion and to assess treatment alternatives in drinking water. Visual examination of the internal surface of copper pipes positioned in the loop revealed signs of localized corrosion (isolated 3 mm diameter mounds of corrosion by-products) after only 72 days. Examination of pipe sections removed from the loops after 101 days clearly showed that localized corrosion was taking place. Cross-section analysis of the pipe showed pits as deep as 0.150 mm that were covered by a thin membrane and a mound of blue-green corrosion products. An ortho- and poly-phosphate blended chemical fed to a second pipe loop, prevented pitting attack, and produced different corrosion by-products. The study showed that simple, inexpensive copper pipe loops can be useful in predicting pitting tendencies of drinking water and in assessing the effectiveness of treatment alternatives.

Formation of plasma technological influence of vacuum arc on the internal surfaces of metal pipes and putting of the protecting coatings

In many cases of industrial applications it is economically profitable or technically necessary to combine bulk features of one material with surface features of another one in a single material. Vacuum-arc treatment of products from inexpensive materials to form new required features of surface layers is more perspective owing to its unlimited feasibility in process efficiency. Pipes are in great demand in oil-gas industries and power engineering. But there are no effective methods for pipe inner surface treatment and pipe coating deposition, which makes it impossible to use inexpensive steel pipes under conditions of aggressive liquids, high temperature, high pressure and other parameters leading to oxidation, erosion and pipe life. Therefore, development of plasma-arc technologies of pipe inner surface treatment and pipe coating deposition is very topical and actual. A specific effect of vacuum-arc discharge on material surface is due to high concentration of energy in a chaotically rapidly moving cathode spot, short-term local heating of surface and its rapid cooling. The technological effect of cathode plasma on surface is based on cathode spot movement. The effect of a plasma flow of cathode spots formed on the outer surface of a pipe cathode and controlled by a system of vacuum-arc cathode spot fixation with magnets placed inside an electrode has been considered. A great number of studies have been devoted to explaining and investigating “anomalous” movement of the cathode spots. It has been shown that the cathode spot moves in the direction of the greatest action of discharge’s own magnetic field and outer magnetic field. The magnets initiate an arc magnetic field that confines the cathode spots and makes it possible to scan (control) them on the electrode-cathode surface and act with a plasma flow and deposit coats on inner surface of a coaxially placed pipe-product. The high efficiency of the plasma vacuum-arc method for pipe inner surface treatment and coat deposition has been found.

Working surface of components made from high-alloy corrosion-resistant steel

The internal (working) surfaces of pipes and other components made from corrosion-resistant austenitic steel are investigated. The influence of the production parameters, the metal structure, and the operating conditions on the surface of critical components is established.

Study on the Effect of Surface Finish on Corrosion of Carbon Steel in CO2 Environment

Standard surface finish used in laboratory corrosion testing may not represent the 'as-delivered‟ internal pipe surface condition, which typically varies from 20 μm to 50 μm. Surface roughness is known to affect the hydrodynamic and mass-transfer boundary layer, thus influencing the corrosion mechanism and rate. The objective of this study is to investigate the effect of various grit surface finishes of 60, 240, 400, 600, 800 and 1200 used in laboratory corrosion testing in predicting field corrosion behaviour. The effect of the surface roughness on the corrosion rate is investigated by varying the specimen surface finishing using SiC abrasive paper of 60, 240, 400, 600, 800 and 1200 grit. The specimen used is carbon steel BS 970 (070M20), tested in stagnant and turbulent CO2 environment at pH 5.5 and 3 wt% NaCl. The corrosion rate is measured by the Linear Polarization Resistance (LPR) Long Term and Custom Sweep, Weight Loss and Electrochemical Impedance Spectroscopy (EIS) method. Surface profiles produced by 400, 600 and 800 grit samples fall within the range of 20 μm to 50 μm, which resemble the 'as-delivered‟ internal pipe surface roughness. Corrosion rates in turbulent flow are higher than static condition for all surface finish. For both static condition and turbulent flow, the average corrosion rates of 400, 600 and 800 grit finish samples obtained differ within 18% and 15%, respectively. In conclusion, based on surface profiles and corrosion rate measured, the practice of 400, 600 and 800 grit surface finish in laboratory testing is acceptable to represent the 'as-delivered‟ pipe condition.

Automating visual inspection of pipes used for natural gas production

Abstract Qatar is a worldwide leader in liquid natural gas (LNG) production and is poised to lead the world in gas-to-liquids (GTL) production with the commissioning of the Pearl GTL facility. Unfortunately, Qatar's gas fields contain non-negligible quantities of corrosive and toxic hydrogen sulfide (H2S), resulting in the ongoing need for expensive and labor intensive pipe inspection to detect and monitor areas of corrosion. Such inspection is critical to plant integrity, worker safety, and to ensure the economic productivity of the facility. Current industry practice relies on manual sensors operated by a worker located externally to the pipe. The complex pipe geometries and sheer number of pipes, result in a sparse inspection process that forces inspectors to extrapolate measurements to large areas of the pipe network that are unseen. To overcome these limitations, we are pursuing a radically different approach that uses an articulated robot to navigate inside the pipe, combined with a vision-based perception system that can build a detailed, registered, high resolution 3D appearance map of the inside pipe surface. By using an articulated robot, we can significantly increase the direct measurement coverage of the pipe network. By using a vision-based perception system, we can build models for visualization of the inside pipe surface that can be directly evaluated for corrosion damage. Moreover, our approach lays the foundation for automating corrosion detection by enabling changes in co-registered multi-sensor fusion (e.g. using magnetic flux leakage) to be evaluated over time. Our work to date has focused on developing monocular and stereo visual odometry systems, which are the core component to building high resolution 3D appearance maps of the pipe surface from a robot crawler located inside the pipe. We have developed algorithms that take imagery collected from a robot moving inside the pipe, and are able to estimate the motion of the vehicle and the resulting structure and appearance of the pipe surface. We have evaluated our algorithms on pipe segments and have generated accurate, high resolution stitched images of the internal pipe surface. We will describe the details of our algorithms, current results, and next steps in our work.

Generation of transfer film and its effects on wear mechanisms in alumina conveying pipeline of mild steel

Pipeline wear is a very complex problem and at present there is limited understanding of the wear mechanisms responsible for the reduction of wall thickness in severe wear regions of alumina conveying pipelines. The ability to determine the wear mechanisms in these areas holds the key in determining the service life of pneumatic conveying pipelines in these industries. In a previous paper it was revealed that delamination and subsequent cracking and spalling of a thin layer plays a major role in material removal in the severe wear regions in the pipeline. The thin surface layer is believed to be the transfer film of alumina generated in the internal pipe surface. In this paper, the transfer film developed in these areas of the pipeline have been analysed to determine its mechanical properties and to correlate the properties with the wear mechanisms observed earlier. In this work, the transfer film formed on mild steel pipes during pneumatic conveying is investigated by using a UMIS nanoindenter. The benefit of using the nanoindenter lies in the very small force that can be applied so that only the properties of the transfer film are measured. The mechanical properties of the film such as the hardness and Young's modulus at different loads are measured. Attempts are also made to measure the fracture behaviour of the film. The elemental analysis of the surface as well as the through depth was conducted using the SEM microanalytical technique EDS (energy dispersive X-ray spectroscopy) and XPS (X-ray photoelectron spectroscopy). The study found that the top layer of the surface is primarily aluminium with hardness value similar to that of sintered alumina.

Corrosion Control: Less Is More

This article discusses a treatment process used by the Tulsa Public Works Department that eliminates soda ash from corrosion control treatment, and uses only caustic soda to protect its pipes from corrosion. Bringing the water slightly above the point of calcium carbonate saturation creates a calcium carbonate film on internal pipe surfaces that protects the pipe material. The article discusses several options that Tulsa evaluated at its A.B. Jewell Water Treatment Plant, explains the chemistry of caustic soda, provides software model calculations, jar test results, full‐scale testing, and compares costs.

Isolation And Characterization Of Some Micro-organisms Contaminating The Air-Conditioning Systems of AL-Ramadi Maternity And Children Hospital

A total of 1200 sampls of various swaps in Maternity and Children Hospital in Ramadi were collected during summer season;1/5/2004 - 30/10/2004. Sources of isolation included the hospital environment ( the floor, patients, beds), the internal air, air of ventilation pipes belonging to the hospital conditioned system with it’s two floors. The samples of the four source groups mentioned above consisted of 400 samples taken from the internal surfaces of air conditioning pipes and 400 samples from the air of internal hospital halls and 400 samples from the hospital inanimate environment such as ground and beds. The study was carried out with ten attempts. Each attempt included ten departments of the hospital. After isolation and identification of the isolates , the followings were found : -The Majority of the microbial isolates were found to be of bacterial origin with a percent of (85.6%) in the whole microbial isolates. -Fungal isolates took the second class with a percent of (8.9%) . -Some of the isolates recorded mixed cultures (bacteria and fungi),but undiagnosed like gram positive rods and fungal threads.Thier percentage was (5.4%) . -Aspergillus sp isolates were found to be predominant among the diagnosed mycotic agents (61.1%) while Candida albicans came in the second range (38.9%). -Gram negative bacteria possessed a higher percentage among other bacterial types which had a percent of 67.5%, while the percentage of gram positive bacteria was 32.5% . -In gram negative bacteria, Klebsilla pneumonia was the highest among the others, its percentage was 16.5% ,while Providencia bacteria was the lowest type with 0.9% . -Coagulase negative Staphylococcus had the highest percent which reached 14.3% , while the α- hemolytic Streptococcus had the lowest percent among the G+ve bacteria which reached 2.7% . -According to the results obtained, the internal surfaces of the airconditioning pipes consisted the highest microbial growth (bacteria, fungai and mixed isolates) in comparison with the isolated smears of the inner air of rooms, grounds and patient's beds. Also, the ground deck in the hospital had the greatest level in microbial pollution in comparison with the first deck.

Polishing Processing to Internal Surface of Non-Magnetic Pipe by Magnetic Abrasive Finishing

It is very difficult matter that polishes the internal surface of the pipe, especially to the thin pipe with the traditional surface technology. Because a usual tool cannot into the inner surface of the thin pipe and automation do not achieved easily. This paper brings up a new method that utilize the characteristic of the magnetic force line may penetrate the non-magnetic material, may using the magnetic abrasive finishing (MAF) method complete to the inner surface of the thin pipe precise polishing. The magnetic abrasive finishing does not need special equipment to complete the complex shape internal surface polishing. Moreover, we already obtained the famous processing effect through the experiment. Meanwhile this paper analyses some factors of influences efficiency, and propose some solution method.

Wear mechanisms in dense phase pneumatic conveying of alumina

Pipeline wear is a very complex problem and at present there is limited understanding of the wear mechanisms responsible for the reduction of pipe wall thickness in severe wear regions. The ability to determine the wear mechanisms in these areas holds the key in determining the service life of pneumatic conveying pipelines in the industry. In this paper the wear mechanisms in an alumina-conveying pipeline have been studied. Observations reveal that the wear mechanisms in severe wear areas in straight sections are similar to those in the reacceleration zones after the bends. This phenomena lead to the assumption that a core flow bouncing from top to bottom section through the pipeline. The study also revealed that crack formation and delamination of surface layer as dominant wear mechanisms in the severe wear regions which are believed to be effects of work hardening and the formation of transfer film in the internal pipe surface. Visual observation, scanning electron microscopy and laser scanning confocal microscopy have been used as surface analysis tools and results are presented. Finally a generic model is presented which has the potential to predict the wear life of a pneumatic conveying pipeline.

Effect of Biofilm Formation on Roughness Coefficient and Solids Deposition in Small-Diameter PVC Sewer Pipes

The purpose of a sanitary sewer is to carry the peak discharge at the end of the design period, and to transport suspended materials under all flow conditions to prevent deposition of solids, and hence, sewer blockages. To accomplish the latter, the liquid must provide for sufficient shear stress to suspend and transport the particles along the sewer. Published design criteria for critical shear stress in sanitary sewers vary significantly. However, the effect of biological film development on the internal pipe surface has been neglected. Experiments conducted utilizing a pilot-scale sanitary sewer installed in the Hydraulics Laboratory at the University of New Orleans, La., provide evidence that the shear stress to move particles of a given size is independent of slope and pipe diameter, but does depend on the effect of biological film on increasing the roughness coefficient. This critical shear stress, to achieve self-cleansing in sanitary sewers, was found to be in the range of 1.1-1.4 N/m 2 , depending on the integrity of the biofilm. Based on this principle, a design procedure applicable to small-diameter PVC pipes with slopes between 0.1 and 0.5% was developed. DOI: 10.1061/ASCE0733-93722007133:4364 CE Database subject headings: Biofilm; Roughness; Sewer pipes; Solid wastes; Waste management.

Investigation of Fe2O3–Al and Cr2O3–Al reactions using a high speed video camera

Self propagating high temperature synthesis is a simple, fast and energy efficient process with a wide range of applications, one of which is the coating of the internal surfaces of steel pipes using a centrifugal thermit process. The process involves a highly exothermic reaction between powder reactants distributed around a steel tube rotating at high speed. Although the process has been widely studied, important features, particularly how the reaction propagates, have not been completely revealed due to extremely high reaction rates and temperatures. In the present work, Fe2O3–Al and, to a lesser degree, Cr2O3–Al reactions were studied under stationary (non-rotating) and rotating conditions using a high speed video camera by which the centrifugal thermit process was, for the first time, recorded optically. Video recordings clearly demonstrate that, in contradiction to current belief, the reaction does not always propagate in a well ordered (spiral) pattern, but involves multiple, randomly distributed ignition sites.

Biofilm in the Parisian suburbs drinking water distribution system

Internal pipe surfaces within drinking water distribution systems (DS) are colonised by bacteria forming a biofilm. Detachment of cells from the biofilm leads to a deterioration of the microbiological water quality. This justifies the requirement for biofilm investigation in DS. This paper presents data on biofilm gained over a long period in the different areas of the Parisian suburbs DS. Two different systems were tested to incubate cast-iron coupons in DS to measure biofilm after colonisation in order to study biofilm. It shows that a simple and inexpensive system can be efficiently used for this purpose. Fixed bacterial biomass was routinely estimated, in this study, on cast-iron coupons by potential exoproteolytic activity (PEPA) and sometimes by epifluorescence microscopic enumeration performed after bacteria detachment from the support by sonication. Bacterial biomass in the biofilm ranged from 0.009 to 0.56 μgC cm-2 in the studied distribution systems. Comparing bacterial numbers in the water phase, on one hand, and fixed to pipe walls, on the other hand, showed that fixed cells were much more abundant than the suspended cells in DS (25 times in a 100 mm diameter pipe). The large set of data gained on biofilm within the Parisian suburbs DS allows us to demonstrate, on full scale data, the major role of disinfectant (chlorine) residual and biodegradable dissolved organic carbon (BDOC) as controlling factors of the biofilm in DS.

Heat transfer in rectangular channels with transverse and V-shaped broken ribs

Repeated ribs are used on heat exchange surfaces to promote turbulence and enhance convective heat transfer. Applications include fuel rods of gas-cooled nuclear reactors, inside cavities of turbine blades, and internal surfaces of pipes used in heat exchangers. Despite the great number of literature papers, only few experimental data concern detailed distribution of the heat transfer coefficient in channels with rib turbulators. This issue was tackled by means of the steady-state liquid crystal thermography: a pre-packaged liquid crystal film was glued onto the heated surface, and the colour map was taken by a video camera at the steady state of a given experiment. After calibration tests to assess the colour–temperature relationship had been performed, local heat transfer coefficients were obtained by applying custom-made software to process the digitised colour images. Liquid crystal thermography was applied to the study of heat transfer from a rectangular channel (width-to-height ratio equal to five) having one surface heated at uniform heat flux and roughened by repeated ribs. The ribs, having rectangular or square sections, were deployed transverse to the main direction of flow or V-shaped with an angle of 45 or 60 deg relative to flow direction. The effect of continuous and broken ribs was also considered. Local heat transfer coefficients were obtained at various Reynolds numbers, within the turbulent flow regime. Area-averaged data were calculated in order to compare the overall performance of the tested ribbed surfaces and to evaluate the degree of heat transfer enhancement induced by the ribs with respect to the smooth channel.

Unique application of large-scale, cathodic-protection system on an MSF plant

This paper describes the main features and performance of a retrofitted cathodic protection (CP) system on six, 5.2 MGD multistage flash (MSF) units which has operated satisfactorily for an extremely long period. The installation of the CP system was precipitated by experience of severe corrosion on many carbon-steel components within months of commencing operation of the MSF units. An extensive impressed-current CP system was fitted to the internal surfaces of painted carbon-steel pipes, rubber-lined water☐es and other components. After one year of operation, it was found possible to drastically reduce the number of anodes and, almost two decades later, the CP system continues to successfully control corrosion on the components. The paper describes the CP system and presents evidence from internal inspections of its effectiveness. The important features contributing to the performance of the CP system, in terms of operating parameters and economics, are discussed. In this respect, evidence is presented of the crucial role, in the corrosion-control process of the concurrent deposition of calcareous scale during operation of the CP system.