Liquid Dynamics
Pulsation Analysis, Diagnostics, Prediction by Software
Pipeline and Pump user Problem -

Pulsation Analysis, Diagnostics, Prediction by Software

LIQUID DYNAMICS Ltd. offer Pulsation / Vibraton and Shock - Analysis & Diagnostics + Software Models
Please call toll free USA 1-888-326-7377 WE HAVE PEOPLE - Not voice mail. --44-161-480-9625 UK
Fluid Flow Control animations by Liquid Dynamics.

Main Menu

plots A, B, C

Input data for
shock modeling
models relations
7 ocillographic

input data

Equations &


LDi Catalog Printable PDF28

Input Data for Shock Modeling
Please collect the following information to use in the selection of pipeline shock, surge, & hammer prevention equipment.

Please first consider whether the addition of pressure vessels
to your piping system, can be avoided completely.

A. Can the need for pump startup surge prevention be made unnecessary?

Please Quote                               

1.) To start a pump without a surge, start the pump slowly. If you specify a pressure that must not be exceeded Liquid Dynamics will quote for working out how slowly you must start your pumps, for you.

Please Quote                               

2.) Start as normal, but allow the flow to by-pass back to suction against a gradually increasing resistance of a slow closing valve in the bypass line. If you state the space available, and the pressure that must not be exceeded, - Liquid Dynamics will quote the by-pass system for you.

Can the need for valve closure shock prevention be made unnecessary?

Please Quote                               

1.) To close a valve without a shock, close the valve more slowly, when you specify a pressure that must not be exceeded, Liquid Dynamics will quote for working out how slowly you must close your valve, for you.

Please Quote                               

2.) Stop the flow going through the fast closing valve in the normal way, but first open another valve in a smaller line from a "T" immediately ahead of the fast closing valve, this line will be piped back to a point nearer to point of volume supply. State the space available and the pressure that must not be exceeded.
Liquid Dynamics will quote for determining the back-pass system dimensions for you.

C. Can the need for pump shutdown back-flow hammer prevention be made unnecessary?
1.) To stop a pump, without a back-flow hammer, slow the pump down gradually; or de-clutch the pump from its driver & allow the pump to spin down, while the inertia of the mass flowing away from the pump pulls liquid through the pump.

Please Quote                               

2.) If you can not decouple the pump drive, then provide a "suck-by" circuit, allowing the void that is sucked out behind the liquid that continues to travel away from the pump, to be filled by sucking past the pump. Liquid Dynamics will quote for establishing the dimensions of the "suck-by" circuit, for you.

**Additionally, Include pressure wave speed (acoustic velocity) m/s when available.

When neither 1 nor 2 of A, B, C, above, "preventive methods" are possible, we can provide a list of companies who can provide vessels suitable for the duties established by a ShockView model of the data that you provide to Ldi, as below.

Both ASME vessel code and the EU Pressure Equipment Directive require your full disclosure of all use parameters.
LIQUID Examples.
Cust. Guestimates from past.
Pls. mark:-
U=From Process Log.
V=Physical tables
Liquid Density.
Specific Gravity
SG @ System Temp.
Grams per milliliter
Grams per Cubic cm.
Kg/Liter or g/cm3
30% NaOH Solution
Ammonia NH3
@ -30 C 0.68
SG g/cm3
Liquid Viscosity
@ System Temp.
Centipoise, cP
w/ absorbed CO2 30% NaOH Solution
Ammonia NH3



Compressibility, reduction
in volume per unit change in pressure, @ system pressure & Temp.
parts of a Liter
per Bar L/Bar
Liters/Kg cm2
w/ absorbed air Water @ 10 Deg. C
Pentene & Pentane+HFacid Ammonia NH3

@ + 40 C 19.6e-5



A Dynamic (dt) equation must be resolved, accurate Time figure is essential
It has an exponential effect.
Pump run up time or valve closure time or pump run down Sec.
("Instantaneous" shall mean 0.01 Sec. 10ms)
1450 motor 6"x4" Centrif.
6" Air actuated butterfly
Diesel driven 24" x 20" Centrif.
Meter stop valve (depending on size)
2.0 Sec.
1.0 Sec
5.0 Sec.
0.05 to 0.300 Sec.



Bulk Modulus, Elasticity of pipe material
Plastic PVC



Pipe Wall thickness mm
Millimeters (Dilation of pipe wall combined & liquid compressibility determines shock reduction & frequency) "effective softness"
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Pipe Internal Diameter      Millimeters mm
Force, Pressure at Pipe Inlet                Bar or Kg/cm2
Pipe Length        Meters (Feet x 0.305)
Pressure that Shock must not exceed.        Bar or Kg/cm2
Theoretical mass flow
Kilograms per second Kg/Sec.
US GPM x 3.8/60 x SG
Acceptable Materials of Construction
Metals                            Plastics
Synthetic Rubbers
Frequency of any current vibration Hertz, Hz.
Vapor pressure at suction temperature for item C2 above.

ShockView Verification
Phone USA 910.270.2737
PO Box 506 Hampstead, NC 28443 USA
UK (for EC) --44(0)161-480-9625
PO Box 47, Stockport, UK SK3-OLH


Liquid Dynamics International provides pipeline and pump user problem analysis, diagnostics, prediction by software, pulsation analysis,swiss replica watches piping system analysis, and piping system simulation. For water hammer and shock solutions pulsation dampening and shock alleviating devices can be replica watches uk obtained from our associate websites:

PulseGuard Inc., and Ltd. for further information about pulsation dampeners / pulsation dampers. - Pulsation Dampener - Pulsation Dampeners - Pulsation Dampers
PulseGuard für Deutschland - Pulsationsdämpfer and to find large gas bag vessels, jumbo bladders, float separator / big bellows type pipeline shock attenuators and expansion / contraction volume compensators, surge alleviators, and shock alleviators. - Surge Alleviators - Shock Alleviators and for information about energy saving in pumping systems, standby emergency power, safety shutdown systems, hydraulic accumulators, and hydropneumatic accumulators. - Hydraulic Accumulators - Hydropneumatic Accumulators to find protection against excess flow. Guard against toxic spills when pipes burst, guard against gushers and fluid loss when hoses split, Flow-Guard guards against excess flow floods with flow fuses and breather bags
Flow-Guard - Flow Fuses and Breather Bags

Liquid Dynamics