Topic
Bellows
About: Bellows is a research topic. Over the lifetime, 15312 publications have been published within this topic receiving 73914 citations.
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11 Jul 1973
TL;DR: In this article, a hollow mandrel or hollow tube having secured around its outer surface along the length thereof according to one embodiment, a flexible open-cell polyurethane foam sleeve and an outer skin formed of a flexible non-permeable plastic such as a vinyl plastic skin adhesively secured to the outer surface of the flexible opencell foam sleeve, and air passages for communication between the interior of the mandrel and the open-cells foam sleeve for communication, the resulting assembly being positioned in a mold for production of cored structural panels.
Abstract: Pneumatic means comprising a hollow mandrel or hollow tube having secured around its outer surface along the length thereof according to one embodiment, a flexible open-cell polyurethane foam sleeve and an outer skin formed of a flexible non-permeable plastic such as a vinyl plastic skin adhesively secured to the outer surface of the flexible open-cell foam sleeve, and air passages for communication between the interior of the mandrel and the open-cell foam sleeve, the resulting assembly being positioned in a mold for production of cored structural panels. In operation the tool assembly is placed under pressure and expanded to force the plastic skin of the assembly outwardly during pouring and setting of the construction material, e.g., a cement or cement-polymer composition in a mold, and after setting thereof the tool assembly is subjected to reduced pressure or a vacuum to withdraw the plastic skin from the set composition, e.g., in the form of a molded panel, to facilitate removal of the tool from the molded panel, thereby forming a cored construction material or panel. Also included as a feature, pneumatic means in the form of a bellows arrangement comprising an external flexible, e.g., rubber, corrugated member, and in the interior of such corrugated member a permeable open-cell, e.g., polyurethane, foam, and tensioning means, said bellows being inflatable for applying pressure to force a contact, e.g., honeycomb, member mounted on the bellows, against an outer surface of a casting composition in a mold, to form an outer surface for a structural molded panel, and which bellows can be deflated to facilitate removal of the pneumatic tool and associated members from the mold following setting of the panel construction. Also included, means providing a combination or arrangement of a plurality of both said mandrel and bellows assemblies for provision of a cored molded structural panel containing outer surfaces of a predetermined, e.g., smooth or textured, configuration.
24 citations
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TL;DR: In this paper, a metal bellows were found to produce a pure note when air was passed through them over a small range of velocity, and sound was produced also by a narrow stream between the bellows and an external pipe.
Abstract: Metal bellows were found to produce a pure note when air was passed through them over a small range of velocity. An axial rod, restricting the stream to a narrow annular cross-section, was usually essential for speech, and sound was produced also by a narrow stream between the bellows and an external pipe. More powerful notes were obtained when the bellows inside the pipe were replaced by helically finned tubes. The pressure distribution in this arrangement was examined. The phase velocity of the waves inside the pipe was much less than the velocity of sound, and this effect is explained by applying the theory of wave propagation in periodic structures. The ratio of the average frequency, at which an air particle passed the protuberances, to the frequency of the sound emitted was usually about 1.6.
24 citations
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15 Mar 1999
TL;DR: A downhole pumping system includes a downhole pump coupled to a motor protector that utilizes one or more retractable and extensible bellows, instead of an elastomeric bag.
Abstract: A downhole pumping system includes a downhole pump that is coupled to a downhole motor. The downhole motor includes a motor protector that utilizes one or more retractable and extensible bellows, instead of an elastomeric bag, to accommodate motor oil contraction and expansion.
24 citations
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19 Apr 2004
TL;DR: Particle damping is a generalization of impact damping technology (also known as acceleration dampers), but also provides additional damping mechanisms when compared with other kinetic energy based vibration dissipation devices as mentioned in this paper.
Abstract: Particle damping is a generalization of impact damping technology (also known as acceleration dampers), but also provide additional damping mechanisms when compared with other kinetic energy based vibration dissipation devices. Due to their inherent design simplicity, in recent years there has been considerable interest in this technology. Most of the reported results have been obtained empirically, however, recently there has been some activity in the construction of analytical/numerical models to simulate the energy dissipating performance of particle dampers. The work described in this paper documents experimental work and representative test results of various particle dampers used to suppress excessive vibration of cantilever type space structural subsystems of various sizes subjected to transient and steady-state vibratory disturbances. It is experimentally demonstrates that the performance of these devices are highly amplitude dependant. It is also experimentally shown that there are three distinct damping performance regions for transient type excitations. In addition to partially filled cavity particle dampers, other particle dampers are also investigated such as particles-in-ball and preloaded particle dampers. In its simplest form, a particle damper consists of a cavity box of various shapes and sizes that are partially filled with particles. Particles can be metallic, ceramic, polymeric, composite or a mixture of various materials. The particle size may vary from application to application and may vary from a few micro-inches to a tenth of an inch or more. The shape of the particles may be near spherical, cylindrical or irregular in shape. The shape, size and material of the particles will influence flow characteristics of the particles in the cavity. Other particle damper configurations are also experimentally studies. In one configuration a polymeric ball is partially filled with particles. The ball is then placed in a cavity that is secured to a vibrating structure. The vibration sets the ball in motion in the cavity. Since the ball is only partially filled with particles, any rolling action of the ball will set the particles in motion against one another and maintain a new surface level, similar to a fluid leveling itself to maintain equilibrium due to gravity. The ball will eventually collide with cavity walls thus functioning as an impact damper with additional frictional losses due to particle friction and other losses due to elastic/plastic deformation of particles and the polymeric material of the ball. In another application, the particles are placed in a confined elastic cavity such as a metallic bellows or a rubber tube and sealed at the ends. The elastic walls of the rubber tube will induce compressive forces on the particles as more and more particles are stuffed into the tube. The amount of particles in the elastic cavity will determine the amount of preload on the particles. Any bending action of the particle filled elastic tube will be accompanied with relative rubbing motion among the particles, thus dissipating energy by dry friction.
24 citations
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07 Jun 1989
TL;DR: In this article, the output of a motor driven compressor is passed through a non-return valve so that when the compressor is turned off supplied air cannot bleed back through the compressor, a pressure switch breaks the electrical circuit should pressure build up excessively at the output.
Abstract: A motor driven compressor is supplied with power from a battery and supplies compressed air at the outlet of an air hose. Compressed air via the hose is supplied to a lifting device, for example a bellows of an invalid seat assembly. In the apparatus the output of the compressor is passed through a non-return valve so that when the compressor is turned off supplied air cannot bleed back through the compressor. A pressure switch breaks the electrical circuit should pressure build up excessively at the output. Additionally, an air dump valve is provided to enable pressure in the output line to be vented to atmosphere. Operation of the compressor is controlled by a hand control.
24 citations