Pressure Resistance Performance Research Articles

A Forward Sensitivity Analysis and Design of U-Shaped Bellows Considering the Radial Compensation Capability Under Internal Pressure

Abstract Bellows serve as integral component within a piping system, which withstand radial displacement loads and internal pressure loads. This study investigates the sensitivity analysis of structure design parameters, such as convolution height, convolution pitch, ply thickness, and convolution number, on radial compensation capability of U-shaped bellows under internal pressure. The influences of the geometric parameters on the strength performance of U-shaped bellows under internal pressure and radial displacement loads are also investigated. A forward design process considering the sensitivity of the structural parameters of the bellows to the bending stiffness and strength is provided. In order to improve the radial displacement compensation ability and to obtain better pressure resistance performance, a mathematical model is established to describe the performance of bellows, and multi-object optimization of bellows is conducted. The results show that the ply thickness has the greatest impact on bending stiffness and strength, and the optimized model has lower stiffness and higher strength compared to the initial model.

Research on the sealing performance of micro-nano composite magnetic powder to liquid media with different viscosities

This paper mainly focuses on the research on micro-nano composite magnetic powder (MNC-MP) sealing liquid medium. Micro-nano composite magnetic powder and temperature-resistant magnetic powder (TR-MP) were prepared, and their magnetization curves were measured. The influence of temperature on the saturation magnetization of the TR-MP was analyzed. The results show that after heat treatment at 100 °C for 10 min, the specific saturation magnetization remains unchanged at 102.55A·m2/kg. The pressure resistance performance of the MNC-MP sealing liquids of different viscosities and the pressure change of the TR-MP sealing silicone oil were studied in the static sealing test. The results show that the higher the viscosity of the MNC-MP sealing liquid, the better the sealing performance, and pressure remains stable at 120 kPa when sealing dimethyl silicone oil. The dynamic sealing test analyzed the relationship between the pressure and rotation speed of the MNC-MP sealing silicone oil. We concluded that when MNC-MP seals dimethyl silicone oil, the effective time of the seal decreases with the increase of rotational speed, and the leakage rate after failure increases as the rotational speed increases. The changes in temperature and torque of MNC-MP and TR-MP sealing silicone oil with time at different rotational speeds were compared. Compared with MNC-MP, the temperature of the TR-MP seal can be reduced by 23.74 %, and the friction torque can be reduced by 17.58 %.

Fenton induced microdefects enable fast water transfer of graphene oxide membrane for efficient water purification

Recent studies have highlighted the great potential of graphene oxide (GO) as the basis of advanced separation membranes for water-related environmental applications. However, pristine GO membranes usually suffer from low water permeability and inadequate stability that limit their further progress and application in practice. Here, a novel approach involving intra-defect construction, combined with cation cross-linking, was used to prepare highly permeable and stable GO membranes for water purification. The preparation was based on Fenton system to achieve enhanced regulation of the membrane structure. The in-situ generated Fe(III) and reaction products (hydroxyl radical and Fe-based nanoparticles) enabled the formation of tightly cross-linked GO nanosheets and favorable pinholes and void defects within the membrane, which stabilized the membrane structure and enhanced its permeability. The resultant membrane achieved an ultrahigh water flux (∼45 L m−2 h−1 bar−1), together with a favorable rejection of Coomassie brilliant blue dye (>91%), natural organic matter (humic acid and bovine serum albumin, >95%) and superior dye/salt selectivity. Moreover, the membrane exhibited a long-term operating stability and pressure-resistance performance. This study offers a facile and scalable method for the design of high performance GO and other two-dimensional (2D) membranes for water purification.

Experimental Study on Waterproofing of Pipe Jacking Shaft and Pipe Joint in Metro Station

Through the indoor waterproof test, the water pressure resistance performance of the waterproof system formed by setting embedded grouting pipe in the middle of double water swelling sealants was studied to ensure that the station pipe joint could meet the operation requirements. The results show that there must be enough distance between the outside sealant and the edge of the pouring concrete, otherwise the new and old concretes cannot be poured tightly; after swelling, the water pressure resistance of sealants is improved in the range of 0-0.55 MPa, with individual differences; the two kinds of slurries have obvious influence on the improvement of water pressure resistance, but the improvement effect of waterborne epoxy slurry is better than that of polyurethane slurry.

A microfluidic diagnostic device with air plug-in valves for the simultaneous genetic detection of various food allergens

The identification of accidental allergen contamination in processed foods is crucial for risk management strategies in the food processing industry to effectively prevent food allergy incidents. Here, we propose a newly designed passive stop valve with high pressure resistance performance termed an “air plug-in valve” to further improve microfluidic devices for the detection of target nucleic acids. By implementing the air plug-in valve as a permanent stop valve, a maximal allowable flow rate of 70 µL/min could be achieved for sequential liquid dispensing into an array of 10 microchambers, which is 14 times higher than that achieved with the previous valve arrangement using single-faced stop valves. Additionally, we demonstrate the simultaneous detection of multiple food allergens (wheat, buckwheat, and peanut) based on the colorimetric loop-mediated isothermal amplification assay using our diagnostic device with 10 microchambers compactly arranged in a 20-mm-diameter circle. After running the assays at 60 °C for 60 min, any combination of the three types of food allergens and tea plant, which were used as positive and negative control samples, respectively, yielded correct test results, without any cross-contamination among the microchambers. Thus, our diagnostic device will provide a rapid and easy sample-to-answer platform for ensuring food safety and security.

Design of a segment-type ring burst test device to evaluate the pressure resistance performance of composite pressure vessels

Composite pressure vessels used to store fuel gases or liquids should exhibit mechanical properties that allow them to withstand high pressures without being damaged. Therefore, an accurate measurement of their mechanical properties is essential prior to their commercial release. A segment-type ring burst test is a facile method to determine the burst pressure; however, the application of uniform pressure to the specimen remains a crucial issue to be addressed. Therefore, in this study, the conventional ring burst test device is modified to enhance the uniformity of pressure applied to the specimen. First, the equation of load transfer ratio from the applied load is derived. To verify the uniformity of pressure in the ring burst test device, the hoop strain distribution of the ring specimen is compared with that of the hydraulic pressure test obtained from the theoretical equation and finite element analysis. Based on the result, the number of segments is determined, and a polytetrafluoroethylene sheet is placed between the segments and the specimen to reduce the discrepancy of the hoop strain. Furthermore, to verify the reliability of the redesigned test device, the strain distribution and fracture behavior are assessed using the digital image correlation method and a high-speed camera.

Fundamental Study of Inflation Pressure Resistance in an Angiographical Tube

This study was designed to clarify the relation between the pressure resistance of an angiographical tube and the amount of contrast medium injected under a connected microcatheter used for interventional radiology (IVR). We investigated the injection pressure and the expansion rate at the center of the tube during contrast enhancement by setting the power injector to 1200 PSI pressure, with 2.0 ml/s injection speed, 10 ml injection volume, 5.0 s injection time, and 0 s rise time for tubes with different pressure resistance performance (low or high). Then we examined the amount of contrast medium material discharged from the microcatheter. The low-pressure resistant tube (less than 140 PSI) injection pressure exceeded the pressure performance. The expansion rate increased to 49%, presenting a risk of rupture. The injection pressure of the high-pressure resistant tube (less than 1200 PSI) was within the pressure-resistance performance. The expansion rate increased to 38%. However, when the contrast medium discharge amount contributing to the image was measured within the injection time under the condition of 10 ml injection for 5.0 s, the former was 2.3 ml and the latter was 4.2 ml. The entire amount was not discharged during the injection period. It became apparent that it is discharged in drips after some time. Results show that the tube expansion caused retention of the contrast medium inside, which decreases the actual amount of the injected contrast medium. From the results, we infer the possibility of preventing reduction of the injected contrast medium amount attributable to expansion.

Multifunctional testing system design for varicose vein therapy apparatus

Varicose veins of lower extremity can be treated effectively with varicose vein therapy apparatus. In order to ensure its therapy effect, it is necessary to test the air tightness of pneumatic circuit and other related performance parameters. The traditional manual testing method has some problems, such as large error, low efficiency and so on. This paper developed a multifunctional testing system based on LabVIEW software to overcome these shortcomings. The system is a combination of software and hardware, which can realise key components calibration, pneumatic circuit air tightness testing, gasbag pressure-resistance performance testing, pressure sensor performance testing and air pump performance testing. The multifunctional testing system realises the goal of automated human-computer interaction testing, which has a bright future in the aspects of application prospect.

Magnetic Circuit Design and Finite Element Analysis of Ferrofluid Seal of Engineering Machinery Hydraulic Cylinder

In order to solve the problem that the construction machinery hydraulic cylinder seal has a short life and cannot achieve zero leakage, This paper creatively applies ferrofluid sealing technology to engineering machinery hydraulic cylinders. In order to obtain the maximum magnetic energy product in the sealing gap of the ferrofluid sealing structure of the engineering machinery hydraulic cylinder, the pressure resistance performance and life expectancy of the ferrofluid seal of the engineering machinery hydraulic cylinder are improved. Based on the theory of magnetic circuit and the theory of ferrofluid seal, the magnetic circuit design of a ferrofluid seal structure with a uniform pole piece with eight magnetic sources is designed. The finite element analysis method was used to verify the pressure resistance of the ferrofluid seal of engineering machinery hydraulic cylinder, and the calculation results were analyzed and discussed. The results show:The design method of the magnetic circuit structure is reasonable and feasible, and has important reference significance for the design of the ferrofluid seal of the engineering machinery hydraulic cylinders.

Experimental study on the influence of chemical sensitizer on pressure resistance in deep water of emulsion explosives

The study on the pressure resistance performance of emulsion explosives in deep water can provide theoretical basis for underwater blasting, deep-hole blasting and emulsion explosives development. The sensitizer is an important component of emulsion explosives. By using reusable experimental devices to simulate the charge environment in deep water, the influence of the content of chemical sensitizer on the deep-water pressure resistance performance of emulsion explosives was studied. The experimental results show that with the increasing of the content of chemical sensitizer, the deep-water pressure resistance performance of emulsion explosives gradually improves, and when the pressure is fairly large, the effect is particularly pronounced; in a certain range, with the increase of the content of chemical sensitizer, that emulsion explosives’ explosion performance also gradually improve, but when the content reaches a certain value, the explosion properties declined instead; under the same emulsion matrix condition, when the content of NANO2 is 0.2%, that the emulsion explosives has good resistance to water pressure and good explosion properties. The correctness of the results above was testified in model blasting.

Flame retardant modification of waterborne polyurethane fabric coating agent with high hydrostatic pressure resistance

Abstract In this work, a series of flame retardant modification crosslinking waterborne polyurethanes (OWPUs) were synthesized. The structures, emulsion performance, film and application properties of prepared OWPUs were investigated. Conclusions drawn from the study were that the incorporation of flame retardant ExolitOP550 makes the particle size of the OWPU dispersions larger, and the result of Zeta potential can be deduced that all polyurethane dispersions are well stabilized. Thermogravimetric analysis (TGA) and thermogravimetric analysis-fourier transform infrared spectroscopy-mass spectrometry (TGA-FTIR-MS) revealed that the ExolitOP550 can catalyze the formation of a protective char layer and release new nonflammable gas. Hence, as the content of ExolitOP550 increases, the limiting oxygen index (LOI) of OWPU films and the flame resistance of OWPU fabric specimens become better and better. After coated, textiles showed excellent hydrostatic pressure resistance performance and the flame retardant property compared with the uncoated counterparts. However, the hydrostatic pressure decreased with the increase of ExolitOP550. In view of the comprehensive performance of OWPUs, especially the application properties, well performed OWPU may be synthesized with 12 wt% proportion of ExolitOP550.

Defects Diagnosis Technology of Water Supply Pipe's Network Using Pipe Endoscope Camera of High Resolution/High Pressure Resistance Performance

The size of pipe network accident caused by aging of water distribution system, rapid urbanization, abnormal climate or a disaster such as an earthquake is gradually becoming larger. Accordingly, it is required to improve the technology to maintain the water distribution system so that the related technologies can be scientifically and systematically applied. The paradigm of Korean water supply service is changing from supply era to maintenance era, and it is required to apply equipment and method to effectively check, diagnose and test the internal condition of the pipe without stopping water supply. If photographing and diagnosis of the burial environment around the water service pipeline and inside the pipe can be carried out without stopping water supply effectively utilizing the surrounding facilities such as straight piping and air valve to the maximum, decrepit pipe (defective pipe) improvement projects can be effectively carried out by making adequate decisions. Also, a systematic and more efficient water supply service maintenance system can be established by building a database of surrounding pipeline directly investigated and selecting priority of direct/indirect evaluation. This study has raised accuracy of a diagnosis by applying a camera capable of securing high resolution without generation of distortion in case of photographing the inside of a pipe, and suggested an application method of the pipe endoscope camera using an inspection hole inside a pipe.