Pulsation dampeners are used for high and low pressures including: pre-charge gas elastomer bladder, system liquid in the bladder, flow through flexible tubes for semi-solids high viscosity and slurry, flexflon ptfe diaphragm dampeners, acoustic pressure pulsation filters with no moving parts and dampeners for the hygienic / sanitary liquid foods drugs and beverages industries.A pulsation dampener provides high attenuation in a narrow quiet band or frequency. The pulsation dampener is tuned to provide a reflected wave 180° out of phase in the narrow band to cancel the undesired pulsation. A silicone polymer contained by a diaphragm is used as the dampening fluid. The pulsation dampener operation is virtually unaffected by changes in working fluid pressure or density. The latter aspect makes the pulsation dampener particularly well suited for use in well drilling operations where pressure pulses in the drilling fluid are used to transmit information to the surface. The pulsation dampeners are tuned to provide high attenuation at a narrow frequency range. By creating a narrow frequency quiet band, pressure pulses in the working fluid can be used to reliably transmit information. The pulsation dampener is particularly adapted for use in well drilling operations where subsurface information can be transmitted to the surface through the circulating drilling fluid on a continuous basis without interrupting well drilling operations. In other nongas charged dampeners the working fluid is also used as the dampening fluid. While such nongas dampeners are insensitive to pressure changes, a change in the density of the working fluid also changes the high attenuation frequency band. In well drilling operations, the density of the drilling fluid is frequently changed which changes the quiet band of high attenuations and which is a serious drawback to that type of equipment. By using the working fluid density insensitive pulsation dampener of the present invention, an operator will be assured of a constant quiet zone or band where pressure pulses from the drilling fluid positive displacement circulation pumps will be highly attenuated. This will enable downhole drilling instruments to reliably signal information to the surface using fluid pressure pulses in the circulating drilling fluid within the predetermined quiet band or zone.
A pulsation dampener is presented which includes a bladder assembly having a bladder which retains its surface area and therefore its capability to dampen pulsations during pulsation dampening. The bladder is axially and longitudinally symmetrical. The bladder assembly comprises a bladder double sealed at both longitudinal ends by the combination of a bladder anchor bolt and a pressed metal end plate to prevent leakage. Pulsation causes the bladder to assume a clover leaf cross sectional configuration, thereby maintaining the bladder surface area constant regardless of pulsation. One end of the housing is machined so that that end may be pressed to gradually reduce its diameter toward the end while causing the wall thickness of those portions of diminishing diameter to remain essentially identical to the thickness of the unmachined unpressed wall portions of the housing.
