Liquid Dynamics - Pulsation Analysis, Diagnostics, and Software Models

Pipeline and Pump user Problem -

LIQUID DYNAMICS Ltd. offer Pulsation / Vibraton and Shock - Analysis & Diagnostics + Software Models
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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 start up 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.

B. 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.

INFORMATION REQ.	UNITS		LIQUID Examples.	Cust. Guestimates from past.	Pls. mark:- U=From Process Log. V=Physical tables W=Guestimation
Liquid Density. Specific Gravity SG @ System Temp.	Grams per milliliter Grams per Cubic cm. Kg/Liter or g/cm3		Water 30% NaOH Solution Ammonia NH3	1.00 1.30 @ -30 C 0.68
					SG g/cm3
Liquid Viscosity @ System Temp.	Centipoises, cP		Water w/ absorbed CO2 30% NaOH Solution Ammonia NH3	1.00 30.0 0.35	Viscosity cP
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	50e-6 @ + 40 C 19.6e-5 11.389E-4	Compressibility L/Bar
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.	Time Sec.
Bulk Modulus, Elasticity of pipe material	Pacalles Pa		Steel Concrete Plastic PVC	2e+11 4.2e+10 2.89e+9	Elasticity Pa.
Pipe Wall thickness mm	Millimeters (Dilation of pipe wall combined & liquid compressibility determines shock reduction & frequency) "effective softness"
Pipe Internal Diameter Millimeters mm		mm	Force, Pressure at Pipe Inlet Bar or Kg/cm2
Pipe Length Meters (Feet x 0.305)		M	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	Kg/Sec	Acceptable Materials of Construction	Metals Plastics Synthetic Rubbers
Frequency of any current vibration Hertz, Hz.			Vapor pressure at suction temperature for item C2 above.

	Liquid Dynamics International provides pipeline and pump user problem analysis, diagnostics, prediction by software, pulsation analysis, piping system analysis, and piping system simulation. For water hammer and shock solutions pulsation dampening and shock alleviating devices can be obtained from our associate websites:
	PulseGuard Inc., and Ltd. for further information about pulsation dampeners / pulsation dampers. PulseGuard.com - Pulsation Dampeners Pulsation-Dampeners.com - Pulsation Dampener PulseGuard.co.uk - Pulsation Dampers PulseGuard für Deutschland - Pulsationsdämpfer
	Shock-Guard.com and ShockGuard.co.uk 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. Shock-Guard.com - Surge Alleviators ShockGuard.co.uk - Shock Alleviators
	Accumulators-Hyd.com and Accumulators.co.uk for information about energy saving in pumping systems, standby emergency power, safety shutdown systems, hydraulic accumulators, and hydropneumatic accumulators. Accumulators-hyd.com - Hydraulic Accumulators Accumulators.co.uk - Hydropneumatic Accumulators Hydraulic and Control Engineering since 1963; See also: Hydrotrole.co.uk Services for Hydraulic and Pneumatic Equipment Recertification and HydroTrole Limited Accumulator Types
	Flow-Guard.com 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