Patent Application
20090045620
The present invention relates to a damper, and more particularly to a damper root ring for a bellows type expansion joint.
Bellows type expansion joints are often utilized in piping and ducting systems adjacent to an unstable flow regime. Fluids which flow along internal convolutions of the bellows expansion joint may produce flow disturbances. One type of flow disturbance is flow induced vortex shedding. Flow induced vortex shedding is an unsteady flow that may occur at certain fluid flow velocities. The flow disturbances and structural response may result in feedback which may cause large displacements adjacent the bellows convolutions and high cycle fatigue. Over a period of time the fatigue may ultimately produce failure in the bellows type expansion joint.
Accordingly, it is desirable to provide a damper to minimize undesirable structural response in a bellows type expansion joint.
The damper according to the present invention provides damping to the motion of a bellows type expansion joint. The damper is located at the root region of the convolutions and is at least partially filled with a damping medium to provide damping therefor. The damping medium may include particles with or without an entrapped fluid to provide particle damping. The damper may be manufactured in segments which have an attachment structure therebetween to facilitate retrofitting of the damper to various conduits that are experiencing or are expected to experience flow induced vibration.
The present invention therefore provides a damper to minimize undesirable structural response in a bellows type expansion joint.
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently disclosed embodiment. The drawings that accompany the detailed description can be briefly described as follows:
Flow induced vortex shedding is an unsteady flow that may occur at certain fluid flow velocities. Flow induced vortex shedding may cause an alternating force adjacent a root region R of one or more convolutions C. Eventually, if the frequency of vortex shedding matches the resonant frequency of the structure, the structure may begin to resonate and the structure's movement can become self-sustaining which may ultimately result in failure.
Referring to
The damper 14 is at least partially filled with a damping medium 16. The damping medium may include particles 18 with or without an entrapped fluid 20 to provide particle damping. It should be understood that various damping mediums may be utilized to provide particle damping. Particle damping is defined herein as the general terminology utilized for a family of loss mechanisms that occur when particles are placed in a container that is in or on a vibrating structure. Friction and impact interactions between the particles 18 themselves and with the wall 22 of the damper 14 provide an appreciable increase in structural damping by absorption of a portion of the energy from the fluid flow F there through. Bellows expansion joints 10 may be operated adjacent an unstable flow regime such that the damper 14 provides added structural margin against high cycle fatigue.
Referring to
It should be understood that relative positional terms such as “forward,” “aft,” “upper,” “lower,” “above,” “below,” and the like are with reference to the normal operational attitude of the vehicle and should not be considered otherwise limiting.
It should be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit from the instant invention.
Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present invention.
The foregoing description is exemplary rather than defined by the limitations within. Many modifications and variations of the present invention are possible in light of the above teachings. The disclosed embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.
