PulseGuard Pulsation Dampeners

Fluid Flow Control Animations
PulseGuard Pulsation Dampeners
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Dampener Calculations - Estimating Pulse Volume and Dampener Size

Estimating the Volume "V" of one movement of one displacer. "Displacer" means one vane, 1 gear tooth, 1 lobe, one cavity, one piston, plunger, or diaphragm. From this figure, & according to the pump type "F" number, a dampener volume may be estimated.

Note: These estimates ignore all of the dynamics, delta time / "dt" consideration, so are quasi static and do not take into consideration pipe system responses. The answers can be valid for residual acceleration head flow fluctuation purposes, but not for pressure pulsation system response, (for which flow through multi connection pressure pulsation dampeners are essential above 5 Hz.)
EXAMPLES: Volume Of One Movement Of One Displacer or "One Flow Fluctuation."
Centrifugal Pump
A centrifugal pump has 11 blades, at 725 RPM it Displacers 500 gpm,
500 gals x 231 in3 per Gallon / 11 blades x 725 rpm = 14.5 in3 displacement
@ 133 Hz.
& use F=7
centrifugal pump pulsation dampeners
Gear Pump
A gear pump has 17 teeth, @ 440 rpm it produces 2 Kg per second.
2 Kg per second x 60 secs per minute x 1000 gms per Kg / 17 teeth per rev x 440 rpm x SG 1.35 = 12 cm3 per tooth
@ 125 Hz.
& Use F=3
gear pump pulsation dampeners
Vane Pump
A vane pump with 23 vanes, driven at 2,900 rpm, pumps 380 barrels per day
40 Liters x 1000 cm3 per Liter / 23 vanes x 2900 rpm = 0.6 ml displacement
@ 111 Hz.
& Use F=5
vane pump pulsation dampeners
Lobe Pump
A tri-lobe pump at 173 rmp, discharges 3 tons per hour
100 lbs per minute x 25 in3 per pound / 3 lobes per rev x 173 rpm = 4.8 in3 per lobe
@ 8.7 Hz.
& Use F=1
tri-lobe pump pulsation dampeners
Multiplex Pump
A quintuplex plunger pump turned at 880 rpm, generates 60+ M3 per 8 Hr shift
2000 gls per hour x 3,800 ml per gallon/60 minutes per Hr. x 5 piston rev x 880 rpm = 28.8ml/stroke
@ 73.5 Hz.
& Use F=0.6
plunger pump pulsation dampeners
Diaphragm Metering Pump
F for duplex diaphragm heads also = 0.8
A simplex diaphragm head pump is pushed by a 100mm diam. piston with a 150mm stroke @ 205 spm

5 cm Piston Radius x 5 cm pist. rad,. x (Pi) 3.142 x 15 cm stroke = 1.18 Liters per stroke
@ 3.4 Hz.
& Use F=0.8
diaphragm pump pulsation dampeners
AODD Pump
The F figure assumes that the air supply to the A.O.D.D. is enough to ensure no return stroke delay.
An air operated double end diaphragm pump empties a 40gl drum in 4 mins., on a 2 second cycle.

10 gls per minute x 231 in3 per gallon/2 diaphragms per cycle x 30 cycles per min. = 38 in3 per end.
@ 1.0 Hz.
& Use F=1.8
aodd pump pulsation dampeners
Hose Pump
The F figure assumes that the size of the shoe or wheel is approx. one third of the volume between shoes or wheels.
A hose pump squelches out 150 liters or effluent sludge per minute, with 3 shoes revolving 15 times per minute.
150 liters/3 shoes x 15 revs = 3.33 Liters between shoes.
@ 0.75 Hz.
& Use F=0.4
hose pump pulsation dampeners
Additional "F" correction factors, for Progressive cavity, Screw, Packed Plunger, Dosing, and Intensifiers, please see Click Here

Using the estimated volume of one pulse to find approx. Dampener volume
= 100 x Volume of One Movement of One Displacer
No of displacers2 x F x The Percentage figure of allowable residual fluctuation
Abbreviation
100 . V
 N2 . F . % age fig. 

"F" is a correction Factor on the square of number of diplacers. Example, Centrifugals are intrinsically good - have a high F, Sandwich diaphragm metering pumps have a low F.

N: N Squared, N Exponent 2, means multiply the Number of displacers by that same number.
Example N2 : 1 Diaphragm head 1x1=1. 11 Blades 11x11=121, 2 Lobes 2x2=4, 3 Plungers 3X3=9
"%age figure" : 0.5% allowable residual fluctuation - use the figure 0.5 in the equation, for a residual fluctuation of say + & - 3%, 3 positive plus 3 negative = 6 - use 6 in the equation, +/- 5% total 10, use the figure 10.
EXAMPLE
  100 x 90 ml per stroke  
= 2,222 ml = 2.22 Litres = 0.59 US Gls.
Use a 135 in3 or greater Dampener
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[From a triplex] 9 x [plunger factor] 0.6 x 0.75 [for 3/4% residual]
IT REALLY IS JUST THAT EASY TO OVERSIZE A DAMPENER BY IGNORING HOW MUCH PULSATION YOU WOULD HAVE WITHOUT ONE.

 



Fluid Flow Control Pulsation Dampeners