Bellows Type Research Articles

다층형 벨로우즈의 성능에 미치는 스테인리스강 물성의 영향

Generally ferritic stainless steels are used for parts of exhaust system in commercial vehicle, because they have many advantages as low price and high corrosion resistant compared with austenitic stainless steels. Even though ferritic stainless steels have such various merits, austenitic stainless steels have been used to manufacture multi-layer bellows with complex geometry because of their high ductility. Recently, the mechanical properties of the ferritic stainless steels are getting improved and alternating austenitic stainless steel. In this paper, the possibility of mass production of multi-layer bellows made of ferritic stainless steel like MH1 and 443CT was studied. Tensile test, ridging test and corrosion test were carried out to observe material properties of STS304, MH1 and 443CT. Three types of prototype bellows were made using STS304, MH1 and 443CT stainless steels, and stiffness and fatigue tests were carried out to evaluate performance of the prototype bellows.

Analysis of Air Supply in Bellows-Type DMFC by Three-Dimensional Simulation

We previously proposed a new DMFC employing a bellows-type assembly. In the conventional structure called the stack type and Planar type, there is a problem of the fuel density varies widely and difficult to achieve connection in parallel. However, in the bellows type structure, the anode and cathode are completely separated. Because of this, it is possible to supply fuel by soaking the entire cell in fuel, and to increase the fuel supply and provide a uniform density. And with this structure, it is easy to connect in parallel. In this paper, The air supply method that was most serious problems in the bellows type structure was studied by three dimensional simulation.

High-Pressure Densities of 1-Alkyl-3-methylimidazolium Hexafluorophosphates and 1-Alkyl-3-methylimidazolium Tetrafluoroborates at Temperatures from (313 to 473) K and at Pressures up to 200 MPa

Pure component pressure−volume−temperature (pVT) data for five imidazolium-based ionic liquids, 1-ethyl-3-methylimidazolium hexafluorophosphate [emim][PF6], 1-hexyl-3-methylimidazolium hexafluorophosphate [hmim][PF6], 1-octyl-3-methylimidazolium hexafluorophosphate [omim][PF6], 1-ethyl-3-methylimidazolium tetrafluoroborate [emim][BF4], and 1-hexyl-3-methylimidazolium tetrafluoroborate [hmim][BF4], were measured with a bellows type apparatus. High-pressure densities of ionic liquids showed smooth trends with temperature and pressure variations except for [emim][PF6] which exhibited a solid phase transition at temperatures below 352.7 K and which solidified at 100 MPa at 352.7 K. Solid densities were measured and were about 6.3 % higher than those of the liquid. Isothermal compressibilities and thermal expansion coefficients were calculated from the Tait equation that was fit to the pVT data. Isothermal compressibilities increased with alkyl chain length which is probably related to the ionic liquid free volume.

Evaluation of effective parameters in metal bellows forming process

Metal bellows have wide applications in aerospace, micro-electromechanical and industrial systems. Forming process of the metal bellows is very sensitive to increasing the ratio of crown to root diameter. In this state, precise control of the parameters is very important in order to form high-quality metal bellows with good thickness distribution and desirable dimensions and resilience. In this paper, a new method has been proposed for manufacturing of the metal bellows and important parameters such as initial length of tube, internal pressure, axial feeding and velocity, mechanical properties and the type of materials were investigated by finite element (FE) analysis (LS-Dyna) and experimental tests. The explicit time integration method is used for modeling the tube-bulging and folding processes. Meanwhile, the implicit time integration method is used for the spring back stage. Finally, the results of finite element method (FEM) and experiments show a very good agreement. The results of the present work could be used as a basis of designing a new type of the metal bellows.

716 ベローズ形伸縮管継手の振動特性解析(機械力学・計測制御III)

716 ベローズ形伸縮管継手の振動特性解析(機械力学・計測制御III)

Development of Bellows Type Vertical Micro Contact Probe

In the semiconductor inspection, number of pads at unit area is increasing and pad array have become irregular 2-dimensional. So we develop a bellows type micro contact probe. Our micro contact probe is a vertical-type micro contact probe for area arrays and narrow pitch electrode pads. We choose bellows type micro contact probe to prevent stress concentration. Our design targets are 120 um pad pitch, 20-50 um OD(over drive) and over 5 mN reaction force. In this research, micro contact probe is made by electroplating(Ni-Co). structural analysis is accomplished by FEM. And characterization of micro contact probe is done by our own mechanical tester. So material property is measured for structural analysis and structural analysis result will be compared with experimental result.

235 ベローズ型伸縮管継手の有限要素法による疲労寿命予測と形状パラメータの影響(締結・接合部の力学・プロセスと信頼性評価3)

235 ベローズ型伸縮管継手の有限要素法による疲労寿命予測と形状パラメータの影響(締結・接合部の力学・プロセスと信頼性評価3)

A Flexible ER Microactuator Using Homogeneous Electro-Rheological Fluid

The paper proposed and developed a flexible ER microactuator called FERMA for in-pipe working micromachines, medical micro robots, and so on. An ER microvalve has a narrow flow channel with electrodes and controls flow of homogeneous electro-rheological (ER) fluid using the apparent viscosity change in an electric field. A conventional ER microactuator that consists of the ER microvalve and a fluid microactuator features simple structure, however, it is difficult to realize a flexible actuator due to the rigidity of the ER microvalve having sufficient channel length for pressure drop. To overcome the problem, we proposed an FERMA having a flexible ER valve called FERV inside a flexible tube. In the proposed FERV, an insulating thin flexible spacer with a slit was sandwiched by a pair of thin electrode sheets and they were wrapped by rubber. The slit in the spacer and two electrode sheets formed a flow channel for an ER valve. In this paper, we fabricated a two-port FERV with 4×3×9 mm3 in size and confirmed the low flexural rigidity and the static characteristics experimentally. Then, we fabricated a three-port FERV and clarified the static and dynamic characteristics experimentally. Finally, we fabricated an FERMA with the three-port FERV and a bellows type flexible tube with 8 mm outside diameter and 8 mm length and investigated experimentally the static and dynamic characteristics in linear and bending motions. The feasibility of the proposed FERMA was demonstrated.

VIBRATION OF DOUBLE BELLOWS TYPE EXPANSION JOINT IN LATERAL AND ROCKING MODES

In this paper, the exact frequency and mode shape expressions are derived for universal bellows type of expansion joint in lateral and rocking modes of vibration. The effect of equivalent support stiffness and mass on the natural frequencies and mode shapes are studied in detail and the results for a range of non-dimensional parameters are presented in graphical forms which should be useful for piping and bellow designers.

3449 ベローズ型伸縮継手の寿命評価に関する考察(G03-9 継手・溶接,G03 材料力学)

3449 ベローズ型伸縮継手の寿命評価に関する考察(G03-9 継手・溶接,G03 材料力学)

A Dilatometer to Measure the Influence of Cooling Rate and Melt Shearing on Specific Volume

Abstract We developed a dilatometer to investigate the specific volume of polymers as a function of pressure (to 100 MPa), temperature (to 260 oC), cooling rate (to 100 oC/s), and shear rate (to 80 1/s). The dilatometer is based on the principle of confined compression and comprises of a pressure cell used in combination with a tensile testing machine with rotation capability. The design of the pressure cell is a mixture of a traditional ‘pistondie type’ dilatometer and a Couette rheometer, i. e. piston and die make up an annular shaped sample spacing. Typical dimensions of annular samples are: inner radius ri = 10.5 mm, outer radius ro = 11.0 mm, height h = 2.5 mm, and a typical mass of about 60 to 70 mg. Silicon grease is used to reduce loss of hydrostatic pressure in the sample due to friction occurring between the solidifying sample and the dilatometer wall. Specific volume measurements at low cooling rate using an isotactic polypropylene (i-PP) are compared with measurements performed using a commercial bellows type dilatometer, showing relative differences in the range of 0.1 to 0.4%. Finally, results for an isotactic polypropylene are presented showing a profound influence of cooling rate and melt shearing on the evolution of specific volume.

Study on the forming parameters of the metal bellows

The manufacturing process of the metal bellows consists of the four main forming processes: deep drawing, ironing, tube-bulging and folding. The tube-bulging and folding processes are critically important because the quality of the metal bellows is greatly influenced by the forming conditions of these processes. Also, the final convolution shape of the bellows is determined just after the springback stage. There are many forming factors pertinent to the overall process of the metal bellows. The representatives are the wall thickness of the pre-form tube, the pressure applied during the tube-bulging and the die stroke for the folding stage. In this paper, a finite element analysis technique is applied to the tube-bulging and folding processes as well as the springback stage. The explicit time integration method is used for analyzing the tube-bulging and folding processes. Meanwhile, the implicit time integration method is used for the springback stage. Combination of these two different time integration methods is widely accepted for simulating the forming and springback stages consecutively. In addition to the FE simulation, effects of the representative forming factors mentioned above are examined by using the Taguchi method. From the factor study, the most important factor influencing the final shape of convolution of the metal bellows is found out. The results of the present study could be used as a basis of designing a new type of the metal bellows.

Evaluation Method for Mechanical Property of Bellows Type Air Spring Made of Woven Fabric Reinforced Rubber.

The stress state on the membrane of bellows type air springs made of woven fabric reinforced rubber is bi-axial when they are pressurized. The material properties for a numerical calculation are needed to use the value examined by bi-axial tensile test. It is very difficult to carry out the bi-axial tensile test because of the problem of making specimens or the way of restraining specimens. Therefore, we have proposed a simplified bi-axial testing method in order to obtain the mechanical properties under bi-axial stress state and presented a database of the material properties by this testing method. Moreover we have calculated the transverse spring constants of the bellows type air springs by nonlinear finite element analysis using this database. These results showed good agreements with the experimental results.

Evaluation of mechanical behavior of new type bellows with two-directional convolutions

Bellows are widely used as the element of expansion joint in various piping systems. Piping systems for industrial plants often suffer excessive deformations or displacements caused by heat expansion, vibration, nonuniform subsidence of ground, etc. Bellows have the function to absorb regular or irregular expansion and contraction in such piping systems. Conventional bellows, however, have difficulties such as the instability of deformations under cyclic loadings, and the inability to absorb torsional deformations. In order to solve these problems, a new type of bellows, so-called “double convolution bellows”, were proposed. This new type of bellows has convolutions in two directions: the first convolutions in the longitudinal direction are the same as the conventional bellows; and the second convolutions are added in the lateral direction. This paper presents a study on the mechanical behaviors of the new type bellows and conventional bellows to examine the deformation behaviors under repeated axial loading, internal pressurizing and torsional loadings, and the results show an improvement in thickness distribution, instability and torsional flexibility.

In vivo experiment leading to clinical application of an electrohydraulic ventricular assist device with magnetic coupling.

We developed an electrohydraulic ventricular assist device with magnetic coupling. The integrated system consists of a blood pump, a water conduit for pressure transmission, a bellows type pumping sac, an actuator for transforming the circular motion of a motor to the linear motion of a pusher plate attached to the pumping sac with magnetic coupling, and a controller. The purpose of the coupling was to prevent excessive sucking against the atrial wall. Number 21 Medtronic Hall (Irvine, CA) mechanical valves were used in the inflow and outflow ports of the blood pump. Maximum dynamic stroke volume was 48 ml, and against a mean afterload of 100 mm Hg, maximum pump output was 7 L/min. Chronic in vivo experiments were performed in three sheep, and during these evaluations the system showed no noticeable problems related to mechanical or electronic devices. When left atrial pressure decreased below 0 mm Hg, the magnetic coupling system decoupled the pumping sac and pusher plate with satisfactory reliability. The device was clinically applied in a postoperative patient with chronic dilating cardiomyopathy, and no significant device related problems ensued. These results prove that the electrohydraulic ventricular assist system with magnetic coupling is a suitable ventricular assist device.

A superconducting linear motor drive for a positive displacement bellows pump for use in the g-2 cryogenics system

Forced two-phase cooling of indirectly cooled superconducting magnets requires circulation of liquid helium through the magnet cooling channel. A bellows helium pump is one possible way of providing helium flow to a magnet cooling system. Since the bellows type of helium pump is immersed in liquid helium, a superconducting linear motor drive appears to be an attractive option. This report describes a linear motor drive that employs oriented permanent magnet materials such as samarium-cobalt as the stator magnet system and a superconducting loudspeaker voice coil type of drive as the armature of the linear motor. This report examines drive motor requirements for a helium pump.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Estimation of Triggering Work of Breathing: The Dependence on Lung Mechanics and Bias Flow During Pressure Support Ventilation

Work of breathing necessary to trigger a ventilator (WOBtr) was calculated during pressure support ventilation (PSV), and the effect of bias flow on WOBtr was evaluated. A spring-loaded bellows type lung model with two bellows placed in series was used to simulate spontaneous breathing. A Venturi mechanism of jet flow generated subatmospheric pressure inside the diaphragm bellows simulated inspiratory effort. The lung compliance (CL) was set at 0.3 L/cm H2O or 0.05 L/cm H2O. The airway resistance (Raw) was set at 5, 20, or 50 cm H2O/L/s. Pressure support levels were increased from 0 to 45 cm H2O. Sensitivity was set at 2 cm H2O. No bias flow was used at first. The WOBtr was calculated using a pressure-volume (P-V) loop derived from the diaphragm bellows movement during the triggering period. We determined WOBtr and its dependence on the various pressure support (PS) levels, CL and Raw. To evaluate the effects of bias flow on WOBtr and triggering delay, a ventilator was put in the PSV mode, with various bias flow rates (from 0 to 20 L/min) at a sensitivity of 2 cm H2O. We found that when no bias flow was used, WOBtr increased with an increase in both Raw and end-expiratory lung bellows pressure which was considered as auto-PEEP. With bias flow, both triggering delay and WOBtr increased. An increase in bias flow at a given PS level resulted in both decreased pressure support time and tidal volume (VT). It is concluded that the bias flow system is not desirable for use during PSV.

Pulsation Control in Pressure Metering Systems

Reliable pressure measurement in pulsating flow conditions is difficult. When an orifice meter is used, two significant errors can arise: the square root error, which is inherent to orifice plates, and the pressure distortion generated in the sensing lines and DP transmitter. This study is concerned with minimizing pulsation effects in the sensing-recording system. The method used involves predicting the system dynamic characteristic and modifying it so that pulsation excitation frequencies and the resonant frequencies of the system do not coincide. A differential pressure metering system is modelled as a acoustic-mechanical assembly that includes a DP transmitter equivalent piston, its cavities and sensing lines. The acoustic-mechanical interaction is shown for the pressure metering system incorporating a bellows type DP transmitter. The influence of the acoustic and mechanical parameters on the system dynamic characteristic is discussed.

Special features of welding thin‐walled structures of the bellows type

Special features of welding thin‐walled structures of the bellows type

External ear canal pressure regulating device and tinnitus suppression device

A tinnitus suppression device using an in-the-canal external ear canal pressure regulating device (125,136,144) to alter the pressure of the fluid of the external ear canal interior of the pressure regulating device. The device has (125,136,144) a body (126,133,146) which can be inserted into the external ear canal (14) and which seals the canal (14) from ambient pressure. An adjustably sized body (126,138,146) such as a collapsible bulbous portion (120) or a bellows type wall (128) provides a mechanism for altering the pressure in the canal (14). Either a valve (132,134) or a mechanical displacement device (152) maintains the pressure differential created.