Bellows

About: Bellows is a research topic. Over the lifetime, 15312 publications have been published within this topic receiving 73914 citations.

Decoupler for exhaust pipe of automobiles

Abstract: The invention discloses a decoupler for exhaust pipe of automobiles including a bellows ( 10 ) made of metal and formed in cylindrical and a repeatedly corrugated shapes for absorbing bending and expansion to maintain the exhaust gas to be airtight; an inner sleeve ( 20 ) in a cylindrical shape, disposed inward the bellows ( 10 ) for protecting the bellows ( 10 ) and passing through the exhaust gas at high temperature; a guide member ( 40 ) disposed at the one end of the bellows ( 10 ) for forming circular-arc surfaces ( 41, 42 ) at both ends of a cylindrical portion ( 43 ), with respect to the motion center of the bellows ( 10 ), wrapped outward the bellows ( 10 ); a cover member ( 50 ) disposed at the other end of the bellows ( 10 ), for having inclined sections ( 51 and 52 ) symmetrically formed at the opposing ends of the body portion ( 53 ) thereof at a predetermined angle, wrapped outward the bellows ( 10 ); first mesh ring ( 60 ) and second mesh ring ( 61 ) disposed between the guide member ( 40 ) and the cover member ( 50 ), forming a sliding surface in contact with body portion ( 53 ) of the cover member ( 50 ) and the circular-arc surfaces ( 41, 42 ) of the guide member ( 40 ); and first cushion mesh ring ( 70 ) and second cushion mesh ring ( 72 ), each disposed between inclined sections ( 51 and 52 ) of the cover member ( 50 ) and the first and second mesh rings ( 60, 61 ), made of compressive and expansive material, wherein compression and expansion of the first and second cushion mesh rings ( 70, 71 ) function to absorb the compression and tension displacement from the pitching vibration. The guide member ( 40 ) slides along the first and second mesh rings ( 60, 61 ) to absorb the bending displacement, thereby absorbing the displacements due to the pitching vibration and rolling motion. The present invention has an effect to improve the durability of the exhaust system and passengers' comfort and prolong the life of the exhaust system as well as reduction of the wear and friction noise.

Pressure balanced bellows seal

Abstract: A pressure balanced bellows seal for a valve or pump is disclosed. The bellows seal includes a seal bellows assembly which is operatively and sealingly attached to the valve stem, a counterbellows assembly which is substantially concentric with the seal bellows assembly, a midplate which operatively joins the seal bellows assembly and the counterbellows assembly in an end-to-end arrangement, and an inert fluid within the cavity formed by the seal bellows assembly and the counterbellows assembly and which is moveable therebetween to compensate for volumetric changes resulting from the axial movement of the valve stem. The inert fluid balances the pressure of the process fluid and distributes it substantially uniformly against the seal bellows assembly and the counterbellows assembly thus substantially eliminating any pressure stresses within the bellows assemblies.

A parylene bellows electrochemical actuator for intraocular drug delivery

Abstract: The first electrochemical actuator with a Parylene bellows for intraocular drug delivery is presented in which the bellows separates the electrolysis actuation chamber from the drug reservoir. The Parylene bellows was fabricated using a novel polyethylene glycol (PEG)-molding process and mechanically characterized. Optimization of the gas generation efficiency of the actuators was performed. We achieved an efficiency approaching 80% and over 1.5 mm deflection with our actuator. Wireless operation was also demonstrated.

Development of a fuel-powered shape memory alloy actuator system: II. Fabrication and testing

Abstract: The second part of this work discusses the fabrication and testing of a fuel-powered shape memory alloy actuator system (FPSMAAS) and its main components. Fuel (propane) is burned in a combustor and its heat is transferred to a working fluid medium, which in turn transfers the heat to the SMA element to drive its martensite-to-austenite phase transformation. For the austenite-to-martensite transformation, the heat is removed from the SMA element by a cooling fluid, from which the heat is then removed via a heat exchanger. The process of implementing the FPSMAAS consisted of three phases of increasing complexity, corresponding to three generations of the actuator system. For the final generation of the FPSMAAS, the SMA element was housed in a rectangular channel, featuring an innovative way of separating the cold from the hot fluid medium that alternately come in contact with the SMA element, in order to minimize the mixing between them. To meet our goal of miniaturization, a multi-channel combustor/heat exchanger and a micro-tube heat exchanger were developed and tested. The final actuator system was composed of pumps, solenoid valves, check valves, bellows, a micro-tube heat exchanger, a multi-channel combustor/heat exchanger and a control unit. The experimental tests of the final system resulted in 250 N force with 2.1 mm displacement and 1.0 Hz actuation frequency in closed-loop operation. The test results for the individual components as well as the final assembled actuator are compared with the results of the numerical analyses conducted in Part I and a good agreement has been demonstrated.

Vacuum die-casting machine with apparatus and method for controlling pressure behind piston

Abstract: A vacuum die-casting machine has a bellows forming a sealed enclosure between the rear of the fill chamber and the piston rod. A vacuum is applied to the enclosure during evacuation of the die cavity and charging of the fill chamber with molten metal. As the piston moves forward, an inert gas at about atmospheric pressure is introduced into the enclosure and extends into the feed tube.