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Pulsation Dampener - In Line Through Flow Pressure Wave Interceptor

WaveGuard No Moving Parts / Acoustic Pulsation Dampener
CAUTION: Generally called a "dimensional drawing" this is a PulseGuard viewsheet. The length to diameter ratio(s) are not to the same scale.

WAVEGUARDS
WaveGuards are pressure pulsation dampeners. WaveGuards are not flow fluctuation reducers. WaveGuards are not designed to address acceleration head, the pressure required to accelerate volume flow, except to the extent to which the compressibility of the volume of liquid within the WaveGuard is helpful.

PURPOSE
To provide a pressure pulsation interceptor which does not overload a pump by increasing the resistance to flow by the imposition of an orifice or series of orifices.

THE BASICS
As a pressure wave, typically traveling at a kilometer per second - plus - in a liquid, will have a decreased amplitude when it is explode through a small hole into a large chamber - AND - when a pressure wave will rebound from a sudden change in diameter, say like a "concentric reducer"

METHOD
Pressure waves are only confronted with a shallow angle "Snorkel", aka "Ram Jet" - code "RJ", which accelerates them toward their point of explosion, instead of bouncing them back to source and increasing the frequency.

APPLICATION
WaveGuard /RJ dampeners are generally reserved for frequencies between the level at which membranes will stop responding, say 30 Hz and 1000 Hz - the level at which WaveGuard /CER are used.
This covers most multiplex, vane, and gear pump frequencies. Wag/RJ are particularly prevalent in the pump discharge systems of reverse osmosis potable water production systems.

CONSTRUCTIONS
WaveGuard RJ dampeners are constructed from pipe with 2:1 SE head ends.

Pulsation dampener to dampen pressure pulsation where pressure is communicated Throughout the system at 1440 meters per second

Having no moving parts - aka bladderless - more accurately described as An "acoustic" wave dissipation type dampener. In principle - captures the pressure disturbances, and reduces their amplitude Without bouncing them back to source, causes minimal pressure drop between
Inlet and outlet. Typically applied to quintuplex water pumping in the reverse Osmosis business, at 50 hz and above.

Construction, having:

1. Internals
an inlet comprising a tube tapering at not more than 7 degrees included angle, smaller to the interior. Internal outlet of 1/2 the diameter of inlet, 1/4th the cross sectional area. And small end not less than 1/12th the diameter of space into which it opens.

2. Pressure bottles' housing / vessel for pulsation dampener - "snubber" - pulsation suppression device - acoustic damper
a. Comprising one part, a damper "body" cylinder with ends integral or otherwise permanently closing said cylinder
b. Said dampner cylinder wall thickness determined by the formula :-
design pressure x internal radius
thickness = ----------------------------------------------------------
allowable working stress x factor ( - 0.6 design pressure)

dampener design pressure being established by an addition, to max working pressure, of 10% - on the basis that a direct acting rv set pressure is 10% above max working pressure. Plus that said rv has a 15% accumulation pressure to fully open. *

in which the factor above is determined by the degree of surety of the cylinder wall being perfect, for example: a "snubber" seamless wall of hot rolled or drawn pipe, a punch forged cup, a forged billet machine bored to form a hollow, the factor is 1

a "suppression device" cylinder formed by any longitudinal welding or joining method the factor is 0,7 where there is a longitudinal joint that has been certified as free of all imperfections by X-ray, the factor may be 0,9

said "allowable working stress" for the dampner material being determined by the lesser of yield strength x 0,625 , or the ultimate tensile strength x 0,25. no allowable working stress shall be determinable unless the ductility of the material and any jointing is at least 20%
elongation at break. said dampener jointing procedure shall have been proven by root, side,
and cap bend tests. further assurance of a jointing method may also be indicated by X-ray, but failure to pass tight radius bend tests is the only acceptable criteria for application to dampner manufacture because they are by definition for a cyclic stress duty, hence ductility for the avoidance of work hardening is of paramount importance. *
nota bene : application of the European static pressure vessel weld procedures which allow only 14% ductility, and qualification by X-ray alone, is not safely useable in cyclic duty dampfner manufacture. *

both "yield strength" and "ultimate tensile strength" here in above, being taken from tables asme ii d, of issue not later than 1995 . note - allowable working stress levels established for vessels for static pressure duty, and published in codes that are not at least 20 year proven for cyclic duty, as applicable to "pulsation snubber - pulse dampers, dampners, dampeners - etc; said stress levels shall not be allowed. *

Generally
a. Dampeners as shown in the accompanying cross sectional / cut view
b. This pulsation suppression device bearing a stainless steel data plate, stamped with the vessel / shop / work order number, that enables the trace ability to file containing all materials and physical property certification.

Features
a. Sufficient volume of liquid, which when computed by its compressibility, is adequate to enable the discharge from a specific pump to deliver its liquid flow in a fluctuating manner without generating not more than a specified amount of acceleration head with the damper acting as an accumulator.
b. So arranged that - without additional cost - pressure pulsation is intercepted by the damper in order to isolate the forcing action of a pump, or valve, from the acoustic response of a system to the residual pressure change

* Customer may specify solely of their own choice and advisability the use of pressure rating called "P max"

Pressure Pulsation Filters / Dampeners With No Moving Parts
Pulsation Frequency Reduction Type
No Moving Parts Fluid Phase Change Type
Fluid System Pressure Pulse Dispersal Type
Pulse Intensification and Dissipation Type
Viewsheets:
No Moving Parts Acoustic Pulsation Filter
In Line Through Flow Pressure Wave Interceptor
Ram Jet and Helmholtz Orifice Type
System Suction Cavitation Preventor


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