Seal Devices Research Articles

Research and application of nuclear fuel embedded intelligent security monitoring technology

Electricity is the foundation of the entire national economy, and nuclear power has become an important part of the power system with its unique advantages. The main process of nuclear power is the process of the nuclear fuel cycle, including the source and preparation of nuclear fuel, nuclear power plants and nuclear spent fuel processing. In the whole process, nuclear safety is the top priority and the key to the sustainable development of nuclear power. In this paper, aiming at the objective reality of high security risk and strict security requirements for nuclear fuel storage used in nuclear power, based on the analysis of nuclear fuel radiation characteristics and safety monitoring requirements, a nuclear fuel embedded system is designed from the aspects of system overall, software, hardware, data processing, etc. Security intelligent monitoring system. The system uses MCU as the control core, is equipped with motion detection and electronic seal devices, and realizes alarm functions such as identity authentication, unauthorized movement, and illegal unpacking real-time monitoring. Experiments and use show that the system can be easily integrated, installed and deployed on the nuclear fuel packaging container, and the operation is stable and reliable, which effectively promotes the steady improvement of the operating efficiency and operating quality of the nuclear energy system.

High-pressure hydrogen permeability model for crystalline polymers

Molded seal devices made of crystalline polymers are widely used in high-pressure hydrogen equipment. A method for evaluating high-pressure hydrogen permeability was recently reported; however, the evaluation cost is extremely high. To select suitable crystalline polymers for molded hydrogen seals or barrier devices, a high-pressure hydrogen permeability prediction method using the polymer structure and its conventional properties is required.In this study, we measured the pressure dependency of the hydrogen permeability of low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polyamide 11 (PA11). We constructed the permeation model for crystalline polymers in terms of the tortuosity induced by their higher-order structures and free volume change in the amorphous region evaluated using PVT method for measuring the relationship between pressure (p), specific volume (v) and temperature (T) in the molten-solid state of a polymer. The results of the pressure dependency of hydrogen permeability were reproduced by the developed permeation model.

On the comprehension of the gas split in loop seal devices

Gas distribution through the chambers of a loop seal in circulating fluidized bed (CFB) units is still difficult to predict and often misunderstood. Dedicated experiments were carried out in an isolated loop seal to assess how the gas fed into a loop seal is distributed under different aeration modes (through the recycle chamber, the supply chamber and both chambers), aeration flowrates and solids fluxes. Experimental results shed light on the non-ideality of the gas-solids flows occurring in these units and, in combination with theoretical considerations, it is demonstrated why semi-empirical models cannot effectively describe the performance of loop seals operating as non-mechanical valves. Recommendations are given for the optimization of the operation of a loop seal as a non-mechanical valve in a solids circulating loop. A method is proposed to characterize the performance of a loop seal in a CFB unit from measurements of that loop seal in isolation mode. • Gas splitting into the chambers of a loop seal is a key issue difficult to predict. • The gas distribution was experimentally assessed in an isolated loop seal. • Loop seal operation as non-mechanical valves leads to non-ideal gas-solids flows. • Non-ideal gas-solids flow pattern establishes the gas splitting into the chambers. • The study gives insights on how to control the solids circulation with a loop seal.

Implementation of exclusion devices to mitigate seal (Arctocephalus australis, Otaria flavescens) incidental mortalities during bottom-trawling in the Falkland Islands (Southwest Atlantic)

In the Falkland Islands, the South American fur seal and South American sea lion spatially overlap and interact with bottom-trawling fisheries. Until 2015, interactions of these species with the Patagonian bottom trawl squid fishery were uncommon. During the second fishing season 2017 a dramatic increase in seal interactions was observed, with a corresponding increase in incidental mortalities. Various mitigation measures were applied, seal exclusion devices (SEDs) fitted inside a net extension inserted between the trawl net and cod-end being the most efficient. The SEDs became mandatory in the fishery in September 2017. Since then, the number of seal mortalities remains negligible. SED efficiency is monitored by 100 % observer coverage. To the best of our knowledge, the Falkland Islands Patagonian squid fishery is currently the only trawl fishery in the Southwest Atlantic with full observer coverage and SED usage. It is hoped in the near future similar mitigation measures extend to other coastal countries whose fisheries also interact with these otariids.

PROSES MANUFAKTUR ALAT PELEPAS SEAL SUSPENSI DEPAN JENIS TELESCOPIC FORK SEPEDA MOTOR

One of the most common damages to motorcycles is damage to the seals on the motorcycle suspension, which results in a large amount of oil leakage. To repair the damage a seal removal tool is needed which functions as a Special Service Tool (SST) which is often used in motorcycle workshops. The variety of types and brands of motorcycles, causing motorcycle workshops must have complete equipment, according to the motorcycles brand that is repaired, this results in the expenditure of excess money, especially in the supply of seal removal devices according to the motorcycle brand. The purpose of this research is to create a flexible Telescopic Fork front suspension seal release device, which can be used for all types of motorcycle brands. The method used in this research is tool design, tool manufacturing process, and testing the application of seal removal tools. It is evidenced from the results of the usage test that the resulting seal removal tool can be used for all types of motorcycle brands, this tool can shorten the processing time, and also does not cause new damage to the repaired components. However, it is necessary to examine the application of occupational safety and health to prevent work accidents in the process of making this seal removal device.

Optimization of Seal Devices for Contra-rotating Propellers

Optimization of Seal Devices for Contra-rotating Propellers

Chest Seal Placement for Penetrating Chest Wounds by Prehospital Ground Forces in Afghanistan.

Thoracic trauma represents 5% of all battlefield injuries. Communicating pneumothoraces resulting in tension physiology remain an important etiology of prehospital mortality. In addressing penetrating chest trauma, current Tactical Combat Casualty Care (TCCC) guidelines advocate the immediate placement of a vented chest seal device. Although the Committee on TCCC (CoTCCC) has approved numerous chest seal devices for battlefield use, few data exist regarding their use in a combat zone setting. To evaluate adherence to TCCC guidelines for chest seal placement among personnel deployed to Afghanistan. We obtained data from the Prehospital Trauma Registry (PHTR). Joint Trauma System personnel linked patients to the Department of Defense Trauma Registry, when available, for outcome data upon reaching a fixed facility. In the PHTR, we identified 62 patients with documented gunshot wound (GSW) or puncture wound trauma to the chest. The majority (74.2%; n = 46) of these were due to GSW, with the remainder either explosive-based puncture wounds (22.6%; n = 14) or a combination of GSW and explosive (3.2%; n = 2). Of the 62 casualties with documented GSW or puncture wounds, 46 (74.2%) underwent chest seal placement. Higher proportions of patients with medical officers in their chain of care underwent chest seal placement than those that did not (63.0% versus 37.0%). The majority of chest seals placed were not vented. Of patients with a GSW or puncture wound to the chest, 74.2% underwent chest seal placement. Most of the chest seals placed were not vented in accordance with guidelines, despite the guideline update midway through the study period. These data suggest the need to improve predeployment training on TCCC guidelines and matching of the Army logistical supply chain to the devices recommended by the CoTCCC.

Effect of temperature on the dynamic performance of C/C composite finger seal

The designs of sealing device have prominent influence on the performance of aero-engine. The high temperature environment during the working process of aero-engine also has important influence on the performance of sealing device which is located in the aero-engine. Finger seal has a flexible characteristic and high price performance compared with the other seal devices, thus it gets more attention, and lots of researchers have studied about finger seal’s performance recently. But so far the dynamic performance of finger seal considering temperature effect is not yet analyzed and discussed. Based on this, an equivalent dynamic model based on distributed mass considering temperature effect is proposed in the paper. The effects of environment temperature and heat through friction on the equivalent structural stiffness of finger stick and contact pressure between finger stick and rotor are discussed. Moreover, the data exchange between the dynamic and thermal analysis is confirmed based on the movement relationship between the rotor excitation and finger stick response. Therefore, the dynamic performance analysis of finger seal including thermal-structure coupling is obtained based on an equivalent dynamic method. The effect of temperature on the dynamic performance of finger seal using this model is analyzed, and the effect of C/C composite structural parameters on the finger seal performance is investigated considering the temperature effect. The above results show that the temperature effect has important influence on the performance of finger seal, so it is necessary to consider the temperature effect when the performance of finger seal is analyzed. The current work further improves the theoretical system about finger seal equivalent dynamic research, and has higher academic significance and engineering value.

The Liquid Condensation Conditions in the Dry Gas Seal System

Dry gas seal is often used as the seal devices in centrifugal compressor and other high-speed rotating equipment, which requires seal gas clean and dry. If there is some liquid in the seal gas, the dry gas seal will rapidly fail. When the seal gas flows through the filters, valves, orifices, seal faces and so on, the gas temperature will decrease resulted from the Joule- Thomson effect. If the gas temperature is lower than the corresponding dew point, there will be liquid condensation in dry gas seal system. Wet air is taken as an example to show how to calculate the pressure and temperature relationship when it is adiabatic expansion. Dew point lines at different conditions are calculated by considering the vapor-liquid equilibrium. Liquid condensation conditions are acquired by comparing expansion lines and dew point lines, and the factors of influencing liquid condensation were analyzed. The results shows that decreasing gas humidity, increasing the gas temperature can effectively reduce the liquid condensation.

Seal exclusion devices in cod pots prevent seal bycatch and affect their catchability of cod

In order to maintain a viable inshore fishing industry, it is important to limit the incidence of seal-inflicted damage to static fishing gear and additional catch losses. Studies in the Baltic Sea have shown that this could be achieved by implementing alternative fishing methods, e.g. by using fish pots instead of lines or gillnets. However, as in net and line fisheries, a pot fishery could also result in bycatch of seals. In order to prevent these bycatches, pot entrances were equipped with seal exclusion devices (SEDs) of various sizes and shapes. A field study was conducted to investigate what effect different types of SEDs had on the bycatch of seals as well as on the pot's catchability. When pots where equipped with SEDs the bycatch of seals was reduced to zero without negatively affecting the pot's catchability. The shape and size of the entrance did have a significant effect on the pot's catchability and the size of the fish. Using symmetrical oval shaped entrances along with larger rectangular entrances divided into two smaller openings increased the pot's catchability.

Yield stress and flow behavior of concentrated ferrofluid-based magnetorheological fluids: the influence of composition

In this paper, the magnetorheological (MR) and magnetoviscous properties of ferrofluid-based iron particle suspensions were investigated. The 2.1-µm mean size Fe particles were dispersed in high-concentration transformer oil-based ferrofluid, the iron particle volume fraction in the resulting nano-micro composite magnetorheological fluid samples varying from Φ Fe = 5 to 40 %. The ferrofluid carrier has φ p = 23 % solid volume fraction of magnetic nanoparticles stabilized with chemisorbed oleic acid monolayer and without any excess surfactant. In the absence of the field, the ferrofluid has a quasi-Newtonian behavior with a weak shear thinning tendency. The static yield stress shows an increase of about 3 orders of magnitude for an iron particle content of approx. Φ Fe = 25 % (Φ tot = 42.25 %), while above this value, a saturation tendency is observed. The dynamic yield stress (Bingham model) also increases with the magnetic induction and the particle volume fraction; however, the saturation of the MR effect is less pronounced. The relative viscosity change has a maximum at Φ Fe = (10–15) % due to the accelerated increase of the effective viscosity of the composite for higher Fe content. Addition of micrometer-sized iron particles to a concentrated ferrofluid without any supplementary stabilizing agent proved to be a direct and simple way to control the magnetorheological and magnetoviscous behavior, as well as the saturation magnetization of the resulting nano-micro composite fluid to fulfill the requirements of their use in various MR control and rotating seal devices.

Dynamic analysis of C/C composite finger seal

A seal device as an important component of aeroengines has decisive influence on performance, reliability, and working life of aeroengines. With the development of aeroengines, demands on the performance characteristics of seal devices are made strictly. Finger seal as a novel kind of sealing device, recently attracts more and more attentions in academic circles and engineering fields at home and abroad. Research on finger seals has been extensively developed, especially on leakage and wear performances under dynamic conditions. However, it is a pity that the work on finger seals has been limited with a single approach that is improving the performance by structural optimization; in addition, the technology of dynamic analysis on finger seals is weak. Aiming at the problems mentioned above, a distributed mass equivalent dynamic model of finger seals considering the coupling effect of overlaid laminates is established in the present paper, the dynamic performance of 2.5 dimension C/C composite finger seal is analyzed with the model, and then the effects of fiber bundle density and fiber bundle preparation direction on finger seal’s dynamic performance are discussed, as well as compared with those of Co-based alloy finger seal. The current work is about dynamic analysis of finger seals and application of C/C composite in this paper may have much academic significance and many engineering values for improving research level of finger seal dynamics and exploring feasibility of C/C composite being used for finger seals.

Effect of blade outlet angle on radial thrust of single-blade centrifugal pump

Single-blade centrifugal pumps are widely used as sewage pumps. However, a large radial thrust acts on a single blade during pump operation because of the geometrical axial asymmetry of the impeller. This radial thrust causes vibrations of the pump shaft, reducing the service life of bearings and shaft seal devices. Therefore, to ensure pump reliability, it is necessary to quantitatively understand the radial thrust and clarify the behavior and generation mechanism. This study investigated the radial thrust acting on two kinds of single-blade centrifugal impellers having different blade outlet angles by experiments and computational fluid dynamics (CFD) analysis. Furthermore, the radial thrust was modeled by a combination of three components, inertia, momentum, and pressure, by applying an unsteady conservation of momentum to this impeller. As a result, the effects of the blade outlet angle on both the radial thrust and the modeled components were clarified. The total head of the impeller with a blade outlet angle of 16 degrees increases more than the impeller with a blade outlet angle of 8 degrees at a large flow rate. In this case, since the static pressure of the circumference of the impeller increases uniformly, the time-averaged value of the radial thrust of both impellers does not change at every flow rate. On the other hand, since the impeller blade loading becomes large, the fluctuation component of the radial thrust of the impeller with the blade outlet angle of 16 degrees increases. If the blade outlet angle increases, the fluctuation component of the inertia component will increase, but the time-averaged value of the inertia component is located near the origin despite changes in the flow rate. The fluctuation component of the momentum component becomes large at all flow rates. Furthermore, although the time-averaged value of the pressure component is almost constant, the fluctuation component of the pressure component becomes large at a large flow rate. In addition to the increase of the fluctuation component of this pressure component, because the fluctuation component of the inertia and momentum components becomes large (as mentioned above), the radial thrust increases at a large flow rate, as is the case for the impeller with a large blade outlet angle.

Two-Phase Flow Field Characteristics Analysis on Seal Cavity for Bellows Mechanical Seal under Variable Operating Conditions

This research based on the vapor-liquid two-phases flow theory and methods, by using the CFD mix-multiphase flow model, the seal cavity vapor-liquid two-phases flow field for the bellows cartridge mechanical seal under such the high-temperature, high-pressure, high-speed as complex working conditions was numerically simulated and analyzed, then the characteristics of the complex three-dimensional flow field of seal cavity caused by the rotation of the sealing ring were obtained by the different position of the injected coolant, and the different cooling effects were contrasted, then the best cooling position were found by analysis. The researching results provide a theoretical basis for the structural optimization design of the high parameters bellows cartridge mechanical seal devices.

On the axial drift of free pistons in acoustic systems.

Unlike the pistons in car engines, or other devices with crankshafts and other mechanical linkages, the pistons in acoustic devices such as pressure-wave generators, thermoacoustic coolers, or Stirling engines are part of a resonant system. The motion is induced by the overall dynamics of the system, but is not rigidly proscribed. It is therefore possible, and exceedingly common, for these pistons to experience axial “drift” from their nominal rest position while running. This most often occurs in devices that use radial “clearance seals” in which the working fluid flows in a very narrow annulus between the piston and the piston cylinder. There is no guarantee that the mass of fluid that “blows by” one way during one-half of the cycle equals the the mass that blows by during the second half; and in general these devices experience net mass transfer through the clearance seal, resulting in a buildup of dc pressure across the piston. This dc pressure tends to force the piston away from its natural center, shortening its useful stroke. Through our work with clearance seal devices, we have learned how to quantify the processes that cause this piston drift, and how to passively suppress it.

AGENCY MATTERS: SEAL-USERS IN PYLIAN ADMINISTRATION

Summary This study aims to provide insights into the patterns discernible in the Pylian sealing practices with regard to the identity of the seal-owners involved. The focus is on reassessing the problem of the function of glyptic imagery and on testing the working hypothesis that differences in the subject matter of the seal devices used to produce the seal impressions may have reflected the hierarchical status of the Pylian seal-owners. On the basis of context, typology and iconography it is suggested that the heirloom signet rings impressed upon the direct object sealings and the combination nodules from the Archives Complex as well as upon a set of hanging nodules from the Northeastern Building designated offices within the Pylian administrative system. In the case of the open irregular string nodules from the Northeastern Building, the Wine Magazine and the Southwestern Building, it is argued that they mainly reflect a system of receipts. Last but not least, the example of a gold ring impression reproducing key palatial iconography is used to demonstrate that the seal devices should be interpreted as visual symbols that acquired their meaning through convention. One of the mechanisms through which the rings and the seals would have been differentiated and associated with individual offices or other institutions was possibly the way specific symbols were embedded within the composition of image.

実験用小形スターリング機関の性能特性

It is an effective method to increase the mean pressure in a cylinder for the improvement of Stirling engine output. However, for low-pressure type Stirling engines that use air as the working gas, gas leakage and frictional resistances in the shaft seal devices become a serious problem. A newly developed one-way type shaft seal of the low frictional resistance based on the same principle as has been applied to the one-way type piston ring, was set in an experimental engine and operated.As a result, it is confirmed that the power of low pressure type Stirling engines can be remarkably increased by using the one-way type shaft seal because the increase of mean pressure in a cylinder can be easily obtained