Terahertz inline wall thickness monitoring system for plastic pipe extrusion

2014 ◽  
Author(s):  
J. Hauck ◽  
D. Stich ◽  
P. Heidemeyer ◽  
M. Bastian ◽  
T. Hochrein
Keyword(s):  
Monitoring System ◽  
Wall Thickness ◽  
Plastic Pipe ◽  
Pipe Extrusion

Elimination of Sag in Plastic Pipe Extrusion

1992 ◽  
Vol 7 (2) ◽  
pp. 140-143 ◽  
Author(s):  
D. N. Githuku ◽  
A. J. Giacomin
Keyword(s):  
Plastic Pipe ◽  
Pipe Extrusion

Plastic pipe solidification in extrusion

2018 ◽  
Vol 38 (6) ◽  
pp. 591-603
Author(s):  
Pongthep Poungthong ◽  
Chanyut Kolitawong ◽  
Chaimongkol Saengow ◽  
Alan Jeffrey Giacomin
Keyword(s):  
Residual Stress ◽  
Cooling System ◽  
Outer Wall ◽  
Solidification Time ◽  
Solidification Temperature ◽  
Pipe Surface ◽  
Plastic Pipe ◽  
External Cooling ◽  
Wall Boundary Conditions ◽  
Pipe Extrusion

AbstractIn plastic pipe extrusion, hot molten extrudate emerges from an annular. This highly viscous liquid is then cooled and solidified, calledquenching, in a quench tank. In this paper, we focus on the external cooling system. We use an adiabatic inner wall and differing outer wall boundary conditions: isothermal and convection. The solid-liquid interface, at the solidification temperature, moves inward with deceleration. We adimensionalize the energy balance and solve for the interface speed in terms of the solidifcation coefficient,λ. We arrive at the exact solutions for the evolving solidified thickness. Finally, we use the residual stress model developed by Jansen [Int. Polym. Proc. 1994, 9, 82–89]. to predict the compressive residual stress at the outer pipe surface. Our new exact solution for the solidification time agrees well with the data from the plastic pipe industry. The goals of this paper are to help plastics engineers calculate the solidification time, to design the cooling chamber and to predict the residual quenching stress.

Remote Monitoring Digitizes Asset-Integrity Management

2021 ◽  
Vol 73 (01) ◽  
pp. 65-66
Author(s):  
Chris Carpenter
Keyword(s):  
Real Time ◽  
Monitoring System ◽  
Wall Thickness ◽  
Remote Monitoring ◽  
Ultrasonic Transducer ◽  
Abu Dhabi ◽  
Corrosion Monitoring ◽  
Electric Pulses ◽  
Ultrasonic Sound ◽  
Integrity Management

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 197168, “Digitalize Asset-Integrity Management by Remote Monitoring,” by Mohamed Sahid, ADNOC, prepared for the 2019 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 11-14 November. The paper has not been peer reviewed. Monitoring of corrosion in process pipelines has always been of paramount importance in ensuring plant-asset integrity. Similarly, steam traps play an important role in ensuring steam quality and, thus, the integrity of critical assets in the plant. The complete paper discusses these two aspects of monitoring asset integrity - real-time corrosion monitoring and real-time steam-trap monitoring - as implemented by the operator. The authors highlight the importance of digitization by means of implementing wireless technology and making data available in remote work stations in real time. Real-Time Corrosion-Monitoring System Corrosion coupons and electrical resistance probes are among the most-tried and -tested methods to monitor corrosion, but the authors detail shortcomings of these systems, focusing their efforts on the option of using nonintrusive ultrasonic sensors for corrosion monitoring. Fixed ultrasonic thickness (UT) monitoring systems measure a localized thickness of vessel wall or pipe through the use of sound waves. They are the fastest method to measure wall thickness and wall loss reliably. The wall thickness is calculated from the reflection of the ultrasonic signal at both external and internal surfaces. UT systems normally include a transducer and a pulser/receiver. The type of transducer used for this application is the ultrasonic transducer, which can be either piezoelectric or variable-capacitive. The pulser generates short electric pulses of energy at a constant rate, which are converted by the transducer into short, high-frequency ultrasonic sound pulses. These pulses are then directed into the material. Any discontinuation or impurity in the path of the ultrasonic sound wave will be reflected and received by the transducer, transformed into an electric signal, and amplified by the receiver to be projected onto the display (in the case of portable UT instruments). Depending on the intensity shown on the display, information about the impurity or discontinuity, such as size, orientation, and location, can be derived accurately. The shortcomings of using portable UT sensors have been overcome by the introduction of permanent UT sensors, which provide wall-thickness measurement continuously at one location in real time. Because these sensors remain fixed at one location for years, it is possible to analyze corrosion at a single point over time, thus detecting early corrosion onset. Real-Time UT Gauging. The operator installed the real-time corrosion-monitoring system in its offshore associated gas (OAG) unit. A UK-based vendor provided UT sensors along with data-management and -viewing software to support data interpretation. Twenty locations were identified in various plants of the OAG unit on the basis of criticality and previously recorded corrosion levels.

Research on Digital Radiographic Inspection of In-Service Fiber Reinforced Plastic Pipe

2020 ◽  
Author(s):  
Shu H. Liu ◽  
Ju Ding ◽  
Jian F. Zhang
Keyword(s):  
Wall Thickness ◽  
Ultrasonic Method ◽  
Hydraulic Pressure ◽  
Petrochemical Plant ◽  
Thickness Gauge ◽  
Fiber Reinforced ◽  
Material Technology ◽  
Fiber Reinforced Plastic ◽  
Plastic Pipe ◽  
Reinforced Plastic

Abstract With the development of material technology, non-metallic materials are applied to pressure pipes in petrochemical plant. Fiber reinforced plastic (FRP) is widely used because high mechanical strength and corrosion resistance. The non-metallic pipeline has been running for more than 20 years in petrochemical plant of China. Due to the fiber material anisotropy, it is difficult to measure thickness and detect defect by conventional ultrasonic method in FRP inspection. According to Chinese pressure pipeline inspection laws and regulations, the main inspection methods are macroscopic examination and hydraulic pressure test. The inspection of non-metallic pipelines has not been specified in detail. Compared with traditional radiographic detection, digital radiographic detection has better contrast and image processing technology, so digital radiographic detection has more advantages in thickness measurement and corrosion detection. Elbows are most prone to corrosion defects due to fluid erosion. In this paper, fiber reinforced plastic pipe is detected by digital radiographic technology. In digital radiographic detection, appropriate parameters and accurate measurement are proposed. The accurate wall thickness of the pipe is obtained and the internal defects are detected. By comparing the measurement results with the actual wall thickness, the measurement accuracy of digital radiographic detection could meet the requirement of ultrasonic thickness gauge in NB/T47013.3. Digital radiographic technology is strongly recommended for FRP pipeline periodic inspection.

Cooling and Wall Thickness Uniformity in Plastic Pipe Manufacture

1994 ◽  
Vol 9 (2) ◽  
pp. 130-140 ◽  
Author(s):  
J. F. T. Pittman ◽  
G. P. Whitham ◽  
S. Beech ◽  
D. Gwynn
Keyword(s):  
Wall Thickness ◽  
Thickness Uniformity ◽  
Plastic Pipe ◽  
Pipe Manufacture

scholarly journals Knuckle formation from melt elasticity in plastic pipe extrusion

2017 ◽  
Vol 242 ◽  
pp. 11-22 ◽  
Author(s):  
C. Saengow ◽  
A.J. Giacomin ◽  
C. Kolitawong
Keyword(s):  
Plastic Pipe ◽  
Melt Elasticity ◽  
Pipe Extrusion

Simulation of Slump in Plastic Pipe Extrusion

1992 ◽  
Vol 114 (1) ◽  
pp. 81-83 ◽  
Author(s):  
D. N. Githuku ◽  
A. J. Giacomin
Keyword(s):  
Numerical Scheme ◽  
Cold Water ◽  
Pipe Wall ◽  
Large Diameter ◽  
Three Dimensional ◽  
Pipe Wall Thickness ◽  
Plastic Pipe ◽  
Model Predictions ◽  
Long Time ◽  
Pipe Extrusion

Extruded plastic pipe leaving an annular die is solidified in a long cooling tank by spraying the outer surface with cold water. The inside surface can take a long time to solidify as the solidification progresses radially inward. This results in flow of molten polymer down the inside of the pipe. This gravity flow of molten extrudate is called slumping, and it can cause serious nonuniformity in pipe wall thickness particularly in large diameter, thick walled pipes. It can also lead to another phenomenon known as “knuckle” formation where melt accumulates at specific locations. A simple numerical scheme to model this flow has been developed. Three-dimensional graphical illustrations of the slumping phenomenon based on this simulation are presented in this paper. The model predictions have been compared with commerical pipe data and they are in qualitative agreement.

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