Pulsation Dampeners with No Moving Parts / Acoustic - Frequency Reduction Type
Frequency reduction type no moving parts / acoustic pulsation dampeners of which the "Foam-Filled" type is best known Dampeners that attenuate pressure pulsation by use of an open cell foam. Although the foam does move, the ability of the device is not based on the movement of the foam. These may be supplied when the contract term says "Bladderless", however, the open cell foam may as easily degrade as can a bladder material, and the open cells of the foam can clog in other than quite clean service. The principle of operation is, that the velocity of pressure wave transfer, whilst being 700+ mph in air, 3500+ in liquids, is even lower than in air through a foam. For example the acoustic velocity for a hydrocarbon crude may be 1400 meters per second, but if the line becomes frothed (or foam filled) the acoustic velocity may drop to 120 meters per second. Basically when pressure has to repeatedly transfer its self from a liquid to a gas to a liquid to a gas, or through the membrane of a bubble wall to the fluid in the bubble, then through the other wall, into another fluid cell, and on and on, the progress is so impeded, it slows right down.
DANGER
This reduction in acoustic velocity can be quite dangerous. Reciprocating pumps are "low frequency devices". The length of a pipe and the speed of pressure wave transfer (the acoustic velocity) determine the frequency of system pulsation.
TYPICALLY
Example: A triplex pump driven by a 1450 rpm 50 hz. motor with a 4:1 reduction box transferring glycol at 1200 psi, produces a primary acceleration head forcing frequency of 29 Hz. The the pipe system first leg to the first "hard 90" is only 13ft 4 5/8ins long, which could normally produces a 342 Hz system response frequency. BUT when a foam type dampener is installed, the now much lowered pipe frequency can coincide with the forcing frequency, the system then amplifies and fractures the pipe. Because of these dangers with extreme lowering devices for frequencies, and the degradation of foams, PulseGuard no longer offer these devices.
Dimensional Drawings, Cross Sectional Views, Cut Sheets:
"Close Coupling" thru-flow installation options CAD File
PulseGuard Pulsation Dampeners with No Moving Parts
PRESSURE PULSATION DAMPENERS THAT DO NOT ACCUMULATE FLOW. Otherwise known as "no moving parts" dampeners, "bladderless" dampeners, "membrane free" dampeners, "fit and forget" dampeners, and (the "iffy" one) the "foam-filled" type.
WaveGuard CER - Pulse Dispersal Type Pulsation DampenersWaveGuard RJ - Pulse Intensification Type Dampeners
CavGuard - Phase Change Type Pulsation Dampeners
Foam Filled - Frequency Reduction Type Dampeners
