Small-bore Tubing Research Articles

Engineering Poster E12: A holistic approach to reducing small-bore fitting and tubing failures in oil and gas facilities

Poster E12 Small-bore piping and instrument tubing vibration failures are not just a hidden risk to production, reliability, and safety, but also a frequent source of emissions through leaks and plant flaring when issues arise. Vibration-induced failure risks are often overlooked and detected too late, despite making up a significant portion of leaks and lost production incidents. Conventional approaches to managing these hidden risks have resulted in recurring failures and unplanned downtime at process plants. Large inventories of Small-Bore Fittings (SBFs) and tubing generally require management as most are integral parts of the plant and can be classed as safety and/or production critical. Small-bore tubing assemblies are at risk of fatigue failure due to a general lack of awareness of the best-practice design for reducing vibration response and how to manage this risk. A holistic approach to manage and pro-actively reduce small-bore piping and tubing vibration anomalies in the field is presented in this paper. This involves a risk-based assessment approach combined with the use of digital tools to register, manage, and visualise the status of the risk to the plant and the improvement in risk with the implementation of remedial actions. Best-practice and a short case study is discussed to demonstrate how the approach can be implemented to effectively reduce and manage vibration-induced small-bore piping and tubing failure incidents. To access the poster click the link on the right. To read the full paper click here

A holistic approach to reducing small-bore fitting and tubing failures in oil and gas facilities

Small-bore piping and instrument tubing vibration failures are not just a hidden risk to production, reliability, and safety, but also a frequent source of emissions through leaks and plant flaring when issues arise. Vibration-induced failure risks are often overlooked and detected too late, despite making up a significant portion of leaks and lost production incidents. Conventional approaches to managing these hidden risks have resulted in recurring failures and unplanned downtime at process plants. Large inventories of Small-Bore Fittings (SBFs) and tubing generally require management as most are integral parts of the plant and can be classed as safety and/or production critical. Small-bore tubing assemblies are at risk of fatigue failure due to a general lack of awareness of the best-practice design for reducing vibration response and how to manage this risk. A holistic approach to manage and pro-actively reduce small-bore piping and tubing vibration anomalies in the field is presented in this paper. This involves a risk-based assessment approach combined with the use of digital tools to register, manage, and visualise the status of the risk to the plant and the improvement in risk with the implementation of remedial actions. Best-practice and a short case study is discussed to demonstrate how the approach can be implemented to effectively reduce and manage vibration-induced small-bore piping and tubing failure incidents.

Characterization Of Biocides Resistant Isolates From Dental Unit Water Line Biofilms By Culture Dependent Approach

The importance of biocides resistant bacterial strains in medicine, industry and the environment has gained significant attention. Microbial contamination of dental unit waterlines is thought to be the result of biofilm formation within the small-bore tubing used for these conduits. Our objectives were to characterize biocides resistant isolates from dental unit water line biofilm (DUWL) using the standard laboratory approaches. Growth curves of isolates established in biocides free and supplemented medium demonstrated less growth in the presence of biocides. O10 | P a g e ptimum pH was 7 whereas; optimum temperature was 37°C. Isolates showed resistance against multiple of heavy metals while fewer antibiotics. Genetic studies were accomplished by performing conjugation and transformation experiments. In two isolates (AWT 21 and PTNPF) transconjugants were observed, while no transformant was recorded in any case. Overall, the findings of this study can be used to profile the metabolic effects of new biocides or biocide combinations upon biocidesresistant biofilm isolates from clinical environment.

Can Vacuum Assisted Venous Drainage be Achieved using a Roller Pump in an Emergency? A Pilot Study using Neonatal Circuitry

There has been much advancement in perfusion technology over its 50 years of progression. One of these techniques is vacuum-assisted venous drainage (VAVD). Many perfusionists augment venous drainage using VAVD, typically from a wall vacuum source. This study explores alternates to providing VAVD if the wall vacuum fails. In two porcine laboratories, ∼36 in. of 3/16-in. tubing was connected to a sucker return port and placed into the roller head next to the arterial pump. The vacuum was monitored with a DLP pressure monitoring system (Medtronic). This system was connected to small-bore tubing and attached to a stopcock on top of the reservoir. The vacuum was regulated using another stopcock connected to a non-filtered luer lock port on top of the reservoir or by a segment of 3 × 0.25-in.-diameter tubing attached to the vent port with a c-clamp. Vacuum drainage was achieved, ranging from −18 mmHg to −71 mmHg by manipulating the stopcock or c-clamp. Changes in venous drainage were seen by volume fluctuations in the venous reservoir. The vacuum was adjusted to account for dramatic changes. Augmented venous drainage using a roller pump can be achieved successfully during cardiopulmonary bypass (CPB). This method of active drainage can be used in lieu of wall suction or during times of emergency if wall suction fails.

Continuous chemical monitoring with osmotically pumped water samplers: OsmoSampler design and applications

Long‐term osmotically pumped fluid samplers, or OsmoSamplers, were developed to reliably and autonomously collect continuous small‐volume water samples for monitoring aqueous environments in remote locations for up to several years. OsmoSamplers provide sequential milliliter‐size samples that, when analyzed, yield high‐resolution time‐series for a wide range of dissolved components. These instruments fill an important niche that has not been addressed by automated samplers or in situ analyzers. OsmoSamplers can be customized for flow rate and duration for addressing numerous scientific questions. The samplers consist of an osmotic pump that continuously pulls fluid sample into a long small‐bore tube. They are thus extremely simple, reliable, and require neither electrical power nor moving parts. Upon recovery, fluid samples are extracted from subsections of the sample tubing, where each subsection integrates a discrete time interval. The time‐stamped subsamples are then analyzed for chemical species of interest. Sample smearing due to static and dynamic diffusion and mixing is kept to a minimum by the use of small‐bore tubing (0.5 to 1.2 mm inside diameter) and low flow rates (0.1 to 12 mL d−1). Theory and laboratory experiments show that sample smearing is not significantly greater than that calculated from static diffusion alone. OsmoSamplers have been tested in the laboratory and deployed at sea. Results from laboratory tests and field deployments illustrate initial results and potential applications.

Inhibition of nitric oxide synthesis augments pulmonary oedema in isolated perfused rabbit lung

The role of nitric oxide (NO) in precipitating pulmonary oedema in acute lung injury remains unclear. We have investigated the mechanism of involvement of NO in the maintenance of liquid balance in the isolated rabbit lung. Thirty pairs of lungs were perfused with colloid for up to 6 h, during which pulmonary vascular resistance (PVR) and capillary pressure (PCP) were measured frequently, and time to gain 5 g in weight (t5) was recorded. Four protocols with different perfusate additives were studied: (i) none (control, n = 11); (ii) 10 mmol NG-nitro-L-arginine methyl ester (L-NAME) (n = 6); (iii) 10 mmol L-NAME with 100 mumol lodoxamide, an inhibitor of mast cell degranulation (n = 7); (iv) 10 mmol L-NAME with 10 mumol 8-bromo-3',5'-cyclic guanosine monophosphate (8Br-cGMP), an analogue of cGMP that may reduce vascular permeability by relaxing contractile elements in endothelial cells (n = 6). Neither PVR nor PCP differed between protocols. L-NAME markedly reduced t5 from 248 (27) min (mean (SEM)) in protocol (i) to 144 (5) min in protocol (ii) (P < 0.05). Both lodoxamide (t5 = 178 (7) min) and 8Br-cGMP (t5 = 204 (10) min) substantially corrected the effect of L-NAME (P < 0.005). Results suggest that maintenance of a low permeability by NO may involve mast cell stabilization and endothelial cell relaxation.

Measurement and control of thin film uniformity in hollow glass waveguides

Hollow glass waveguides provide an attractive means for the delivery of IR laser power and for broadband temperature and chemical fiber sensor applications. These waveguides are made using liquid- phase chemistry techniques to deposit a thin dielectric film of Agl over metallic Ag on the inside of small-bore silica tubing. By controlling the thickness of the Agl film, we can tailor the optical response of the guides to give low loss at selected IR laser wavelengths or to produce a broadband response. In either case, the losses depend on the thickness uniformity of the Agl film. Initially, the Agl film thickness varies as much as 14% from end to end of a 6-m long guide. A faster Agl deposition rate reduces this variation to only 1.3% over a 5-m long waveguide. This leads to a reduction in the total loss for the hollow guides in the 2 to 12 ?m region.

Organization of Chemically Activated Food Search Behavior in Procambarus clarkii Girard and Orconectes rusticus Girard Crayfishes

The feeding responses of decapod crustaceans to chemical stimuli have most often been evaluated in terms of one defining act, ignoring the organization of the behavior. To gain greater insight into foraging behavior, we considered the organization of food-search behavior in evaluating the responses of two species of crayfishes to a feeding stimulant. We also examined the effects of food deprivation on the behavioral organization and whether a behavioral dichotomy exists between food search and feeding behavior in these species. Individual crayfish of the species Procambarus clarkii and Orconectes rusticus were presented with infusions of a feeding stimulant consisting of a supernatant leachate of 100 ml water and 1 g of fish flakes. The stimulant was injected with a syringe and small-bore plastic infusion tubing into the center of a behavioral arena 25 cm square and 15 cm deep. Total injection time was 20 s. Experimental groups were presented with either the full-strength leachate (100%) or one of five dilutions: 75%, 50%, 25%, 10%, or 0% (controls) of full-strength. The feeding stimulant was presented either the day after the crayfish were fed or after one week of food deprivation. We analyzed three components of food-search behavior--detection, probing (near-field search), and locomotion (far-field, or distant, search)--recording the order of occurrence and the latency time to initiation for each behavior. When presented with the stimulus following regular feeding, both species responded to concentrations {ge}50% full-strength with probing behavior (near-field search) prior to locomotion, and to concentrations <50% full-strength with locomotion prior to, or even in the absence of, probing. Detection always occurred first. These results indicate that chemical stimuli preferentially activate distant food search in both species and that a behavioral dichotomy exists between food search and feeding behavior. One week of food deprivation had no effect on the organization of food-search behavior in P. clarkii; however, groups of unfed O. rusticus presented with 25% and 10% full-strength concentrations probed prior to locomotion, indicating a change in behavioral organization.

Multiparametric analysis of waterline contamination in dental units.

Microbial contamination of dental unit waterlines is thought to be the result of biofilm formation within the small-bore tubing used for these conduits. Systematic sampling of 121 dental units located at the dental school of Université de Montréal showed that none of the waterlines was spared from bacterial contamination. Multilevel statistical analyses showed significant differences between samples taken at the beginning of the day and samples taken after a 2-min purge. Differences were also found between water from the turbine and the air/water syringe. Random variation occurred mainly between measurements (80%) and to a lesser extent between dental units (20%). In other analyses, it was observed to take less than 5 days before initial bacterial counts reached a plateau of 2 x 10(5) CFU/ml in newly installed waterlines. Sphyngomonas paucimobilis, Acinetobacter calcoaceticus, Methylobacterium mesophilicum, and Pseudomonas aeruginosa were the predominant isolates. P. aeruginosa showed a nonrandom distribution in dental unit waterlines, since 89.5% of the all the isolates were located in only three of the nine clinics tested. Dental units contaminated by P. aeruginosa showed significantly higher total bacterial counts than the others. By comparison, P. aeruginosa was never isolated in tap water remote from or near the contaminated dental unit waterlines. In conclusion, dental unit waterlines should be considered an aquatic ecosystem in which opportunistic pathogens successfully colonize synthetic surfaces, increasing the concentration of the pathogens in water to potentially dangerous levels. The clinical significance of these findings in relation to routine dental procedures is discussed.

Capnography During Transtracheal Needle Cricothyrotomy

Capnography During Transtracheal Needle Cricothyrotomy

A small-bore flow detector for liquids

A thermal flow-detector assembly based on the Peltier effect and associated electronic circuit is described. The system may be used to detect gross changes in the flow of liquid in small-bore plastic tubing.

A high-resolution system for gradient analysis

A high-performance semiautomatic apparatus for the analysis and fractionation of density gradient preparations is described. The critical parameters of length and diameter of the conducting system, smoothness of stream line, and nonpulsatile flow have been examined and brought close to a practical optimum. In this system, the centrifuge tube for analysis attaches to a tube cap mounted directly under the cuvet housing of the spectrophotometer. A syringe pump filled with a dense solution displaces the gradient solution upward through a conical tube cap, through a vertically oriented, straight-flow-path cuvet, then downward through a short length of small-bore tubing to a fraction collector below the cuvet compartment. The apparatus was made by adding easily fabricated or commercially available accessories to a standard recording spectrophotometer. The resolving power of the system is more than sufficient for analyzing the banding pattern of 5 ml gradient preparations of subcellular particles. Different tube sizes are readily accommodated, the apparatus is inherently free of bubble trapping, and it has been found reliable and convenient to use. Excellent results are obtained with cesium as well as sucrose gradients.

General-purpose machine tool for winding round and flat fins onto small-bore tubing for brazing

General-purpose machine tool for winding round and flat fins onto small-bore tubing for brazing

Gas Pumping in Continuously Operated Ion Lasers

Gas ion lasers <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> operate at discharge currents of several amperes in small-bore tubing. Under these conditions the cischarge acts to pump gas from the cathode to the anode <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and pressure differences in excess of 10:1 can be established in less than one minute of dhscharge operation. Since the optimum pressure range for laser operation in narrowly defined relative to the range of pressures existing in the discharge tube (see Fig. 1). laser action usually deteriorates or goes out shorty after turn-on.

A detector for use with capillary tube columns in gas chromatography.

A RECENT development in gas Chromatography is the use of columns made from metal capillary tubing, the inner surface of which is coated with a thin layer of stationary phase1. These columns promise greatly enhanced performance and resolution in the separation of volatile substances compared with the conventional packed-powder columns; for optimum performance, however, capillary tube columns require small-bore tubing, a thin layer of stationary phase and a slow rate of gas flow, approximately 1 ml./min. The small dimensions of these columns necessitate small loads in the region of 1 µgm. of the mixture to be separated, otherwise the stationary phase would bear excessive concentrations of the various components and the resolution of the column would suffer. The slow rate of gas flow combined with the outstanding resolving power of the columns causes the emergence of the more volatile components in a gas volume of only a few µl. These two properties of the capillary tube columns impose severe restrictions on the type of detector suitable for observing the emergence of vapour from the column. The smallness of the load demands high sensitivity, and the smallness of the retention volume demands a detector with a sensing volume at least as small. A detector was reported in which the concentration of vapour molecules emerging from the column was measured in terms of their ionization following collisions with metastable rare-gas atoms2. This detector is more than sufficiently sensitive for use with the capillary columns; it is, however, much too large (1–10 ml.) and cannot simply be scaled down in size to accommodate the requirements of the capillary columns. This communication describes a modified version of the detector with a sensing volume in the region of 1 µl.