PulseGuard Pulsation Dampeners

Fluid Flow Control Animations
PulseGuard Pulsation Dampeners
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Pulsation Dampeners Safety Installation Operation and Maintenance

Read this first - Beware of "Pressure Vessel Codes"

Contents
PulseGuard Pulsation Dampeners PDFPDF Printable Pages
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This Manual is NOT A CATALOG
For Occupational Health and SAFETY
With PRESSURE equipment LAWS
This manual MUST be in the hands of the: Installer, Operator, Service Tech.
Toll Free 1-888-DAMPERS (326-7377)

Dampener: Installation, Operation, Maintenance, Spare Parts (replacement membranes, diaphragms, bladders)

SAFETY WARNING

 

MSDSs, Material Safety Data Sheets, are not applicable to our products as they aere classed as "OBJECTS" and MSDSs are only relevant to substances;
BUT the disposal of all membranes that are being replaced, and that are made from elastomers and plastomers, must be in an appropriate manner for the territory and its legislation concerning waste or used, elastomeric and plastomeric components.
If in doubt, please return all used elastomeric and plastomeric components, to the factory for disposal, complete with the "shop order" or "work order" number from the data tag on the vessel from the membrane was removed.

1. Check the data on the dispatch note. (see picture below)
This is the only information provided with your contact documents. We were unable to check the suitability of the dampener for any unspecified application information or safety in use.
Where you are unsure of the suitability? Please ask your purchasing agent to contact the factory with the missing information.
accepts no liability for safe use of dampeners where information was not disclosed.


Check "PRESSURE RATING" - go to Checking Pressure Rating Safety.
Check the 5 items under "SAFETY GAS OVERLOAD PROTECTION" - go to Safety & Gas Overload Protection.
Check the page "SAFETY AND LIQUIDS" - go to Safety and Liquids.
Check the page "SAFETY AND PIPING" flow & frequency - go to Safety and Piping.
Check "REQUIRED PERFORMANCE" - go to Checking Required Performance.
--THEN--
As a poor dampener installed correctly, is far better than a superb dampener installed incorrectly, turn to the installation by pump type page.
Your stated performance requirement is only guaranteed by correct installation.
BEFORE you start pumping READ OPERATION page Nbrs.


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CHECKING PRESSURE RATING SAFETY

 

The design pressure is shown as part of the dampener part number code:
EXAMPLES:

DESIGN PRESSURE
Design pressure is as used in the stress calculations for the dampener capsule or "vessel" and is derived as follows:-
Where for example, it is disclosed to PulseGuard, that the system is "a 150# flanged system at 200°F and the ANSI B16.5 flange tables state that the Max Allowable Working Pressure for a 150# flange at 200°F is say 375 psi, then PulseGuard must assume that the system Relief Valve static set pressure can typically be up to 421 psi. And without special knowledge of the relief valve characteristics, it must be assumed that the "accumulation pressure" to fully open such a valve is typically an additional 15%, then the design pressure must become 474 psi.

The above procedure for establishing "design pressure", allowing a compound 27% overage is not mandatory, the end used may purchase on the basis of stating that MAWP and Design Pressure are the same figure, but such practice, though often the result of ASME VIII and other code practice, is at the end users own risk. PulseGuard advises that using MAWP=Dp is inadvisable without an investment in a full fatigue analysis.

ANSI B16.5, tables. Allowable pressure ratings for schedules of pipe, the DN-PN European flange norms, the results of Shock analysis like LDi "SHOCKVIEW" and "PULSEVIEW" are all useful guides, however there is no real substitute, to the 40 year track record, and PROOF testing every design change to destruction, of our predecessor licensees Liquid Dynamics International Inc. & Ltd.

NOTE:
Where the setting of Design Pressure and the choice of allowable working stress figures are from current European PRESSURE EQUIPMENT DIRECTIVE "good practice" codes, OR from ASME tables, PulseGuard accepts no responsibility for the resultant strength nor fatigue life. In general those practices are only applicable to equipment that is not subjected to pulsation - in some codes called "SNUBBING" or use as a "SNUBBER".

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SAFETY AND GAS OVERLOAD PROTECTION

 

Pulsation dampener , of the gas cushion type:
1. Always de-pressurize both gas cushion, and liquid, before service.
2. Use NITROGEN, (commercially) oxygen free nitrogen, also known as "O.F.N."
This is precaution against a "diesel" explosion.
If oxygen were in the dampener cushion chamber, and if it had been assembled with a hydrocarbon lubricant, and then a sudden pressure increase or shock occurred the rapid compression of the air or oxygen in the presence of hydrocarbon could cause a diesel explosion. The intense heat of the explosion can generate pressures in excess of the failure pressure of the dampener .
The end result could be flying components that endanger life as well as the system to which the dampener is installed.
3. Do not use CO2, instead of Nitrogen. Yes, CO2 is inert, but CO2 will permeate membranes and seals of nearly all known fexibee elastomer and plastomer separator types.
4. Always ensure that there is a direct acting relief valve, safety overload protection, or burst disk, in the system. That it is connected in a manner than can not be isolated by a block valve, from the dampener . This is because in the event of a fire, the gas in a dampener will try to expand. Being enclosed, and unable to expand, it will increase its pressure. At the same time the materials of construction will become weaker. In dampener design that are NOT designed to "fail safe", for example those built to ASME (dangerous) code, there may be a burst. The burst will have the stored energy of the pressurized gas behind it. This can spread the fire, endangering the life of emergency response persons.
Note: Even under the CE pressure equipment directive CE marking code, gas burst discs are not mandatory.
If you are in Europe or the USA, you may have a dampener that is not constructed in accordance with our safety design code. This manufacturer removes all warranties of safety in the USA where the equipment is made to ASME or CE rules, so be sure your system is protected by an over-pressure relief device. Also Note: Canada no longer accepts vessels to American code, being adequately safe.
5. Ensure that your mounting method does not prevent built in fail safe features from protecting you.
SEE BELOW:


Do NOT mount beneath anything that could stop gas end swell.

Do NOT mount between brackets that could stop bolt elongation.





Do NOT mount in clamps that could stop end "bell mouthing".

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SAFETY AND LIQUIDS

 

Compatibility with environment & pumped liquid
There are two primary dangers with incompatibility of pumped liquid or environment.
1. That liquids will escape: (see the PulseGuard safety difference below)
a). Seals and membranes can degrade before the first planned service date.
b). The velocity of the leak can cause physical injury or death.
c). The leakage could be of a toxic substance, or dangerous to the environment.
2. Vessel failure:
Corrosion can cause a violent burst, or over time corrosion stress cracking.

Commonly overlooked examples:
It can be safe to use 316/316L stainless steel for pipes carrying salt water and brine. This is because at flow velocities above 2 meters per second, the surface is "passivated".
-On the other hand -
Inside a filter or dampener , the velocity is lower, stainless can become like Swiss cheese, this is a danger with titanium modified stainless also. Cupro-nickel is a better choice. Where a , Liquid inside the bladder type of dampener is provided, the small end plug or "liquid contact part" could have been made from MONEL. There is a general believe that PTFE, DuPont TEFLON, & , resist everything. Exceptions:- Ex/EG Nitric acid, Bromine -ides -ics, Chloros & Flouros -ides ICS

So when installing a 316L or DuPont Teflon dampener , you still need to double check.
Where substances are toxic, carcinogens, or are pyroforic, check the dampener has a secondary containment sealing and double layer membrane with leak detection from between them.
ALTERNATE dampener TYPES ARE SHOWN ON THE INSTALLATION BY PUMP TYPE PAGE.


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SAFETY AND PIPING

 

SAFETY CONSIDERATION WITH PIPING BASE BLOCKS
Prevent Multiple Over Pressurizations.

1. Pressure testing your pipe system generally implies a sustained pressure of 1.3 to 1.5 times your design pressure.
With the introduction of higher allowable working stress figures in the USA, in line with those used in Europe, it is NOT normally allowable to subject pressure vessels to repeated pressure above design pressure.
To enable you to test the complete system pressure integrity, but still not over-pressure your dampener ,standard dampeners fit piping base blocks which become part of the pipe system, and saves you "T" pieces, 3 fittings and 3 NDE jobs. has flow through plates that bolt in place of the dampener - which is supplied with its own "Hydro-Test" verification.
Prevent pipe loadings from stressing the vessel.
2. Whilst saving installation cost and ensuring pipe integrity testing, piping base blocks, add safety by ensuring that nozzle loadings are not applied to the vessel shell. Differential expansion and contraction of the pipe, shaking in the XY&Z planes does not apply fatigue stress to the dampener vessel.
Service down time, and or fast change-out is facilitated by simply unbolting the dampener capsule from the "O" ring face seals of its base.
Ensure Decontamination Before Servicing.
3. Being normally multiported flow through, piping bases provide the safety of being in-place flushable before service, protecting the service technician.
Ensure Accurate Pressure measurement by your instruments.
4. If the flow through facility, which also enables the dampener to intercept pressure wave activity that causes fatigue, is not required in your application, you may still pipe a "T" to one connection and save money by using the other for protecting your system Instrument tap from transients, or your relief valve from bouncing.

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CHECK FLOW RATE FOR PIPE SIZE, AND PULSE FREQUENCY

 

Smaller pipe dissipate pulsation, a flow velocity not below 2ft/sec 0.6m/sec for suction and not less than 7ft/sec 2 meters/sec, on discharge is best. For pulse frequencies above 7 cycles/sec & Hz. flow through interception, as shown below is essential.

For more on Piping Base Layouts, please CLICK HERE.
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CHECKING REQUIRED PERFORMANCE

 

The characteristics of the dampener depend on the data for the pump system and what level of "smoothness" performance (see below) your require.

COARSE DAMPENING
MEDIUM DAMPENING
FINE DAMPENING

MECHANICAL DAMAGE PROTECTION

Pulsation Dampeners - Pipe Stress Fatigue FracturePipe Shake, Fatigue, Weld Cracking, & Over Stress Unions, Flanges, & Fittings.
The level of allowable pressure pulsation, depends on three factors: 1. Diameter of pipe. 2. Operating Pressure. 3. Pulse Frequency. A nomogram - or "3 axis Graph" - to help you specify allowable residual pressure fluctuation has been included (see below).

Residual Pressure Pulsation / Flow Fluctuation

AT A MINIMUM - CHECK BELOW, THAT SYSTEM PIPE A.H., + PIPE FRICTION, + LACK OF "OVERLAP" FROM SYSTEM LIQUID COMPRESSIBILITY; IS NOT PRODUCING GREATER SYSTEM PRESSURE PULSATION THAN ALLOWED, TO PREVENT PIPE SHAKE FATIGUE FRACTURE (Per API 674 etc. below)

WHEN YOUR SYSTEM PIPE AND FITTINGS PLUS LIQUID cP, SG AND COMPRESSIBILITY PULSATION, HAS BEEN CHECKED AGAINST THE ABOVE NOMOGRAM - PLEASE REVIEW THE PAGE CALLED "CHECKING REQUIRED PERFORMANCE" (directly above).

 

PulseGuard Pulsation Dampeners
Phone: 910-270-2737 • Toll Free: 1-888-DAMPERS (326-7377) • Fax: 910-270-2739
295 Sloop Point Loop Road, Hampstead NC, 28443 USA • Contact Us



Fluid Flow Control Pulsation Dampeners