Suction Stabilizers
Surge Absorbers
Thermal Volume Expansion Compensators
Flowguard Models
Certifications:ISO 9001, ASME "U" and "UM"
Flowguard, Ltd. offers just about the broadest line of product of its type in the world today. A U.K. company, Flowguard, Ltd. is an ISO 9001 certified manufacturer. Their type accepted line of pressurized vessels are available in such a wide variety of designs and sizes as to be able to solve most any hydraulically induced pulsation, vibration, or rapid surge problem. Specialized, custom designed units are common place for Flowguard, but their standard product offering consists of: elastomeric bladders models featuring a simple top access design which allows the easiest possible field maintenance; floating piston designs for low pressure, high volume services, Teflon diaphragm and Teflon bellows models for aggressive liquid services; special flow-through designs for slurry services, and a proprietary metal bellows design for extremely high temperature services.
As a Pulsation DamperBack to Top
Pulsation dampers are normal applied immediately downstream of reciprocating, positive displacement (PD) pumps. Whether simplex metering pumps or large triplex machines, reciprocating PD pumps produce pulsating flows. And with each pulsation comes a resultant pressure peak. These pressure peaks may not be desirable in a given piping system, therefore the need for pulsation dampers. Generally, the application of pulsation dampers is based on one or more of the following criteria:
- to prevent potential pipe hammer / vibration
- to reduce the load on the pump itself
- to minimize or eliminate pulsations for the benefit of downstream instrumentation
- or to minimize or eliminate pulsations as a dictate of process
In these instances, the size of the pulsation dampers relative to the displaced volume per stroke of the pump, limits pressure peaks to a pre-determined level. A gas charge pressure of nominally 80% of mean system pressure is separated from the process fluid by some sort of membrane, e.g. elastomeric bladder, diaphragm, or bellows. If actuality, these devices work much like a filter in a power supply as it converts the ripple of a rectified sine wave into dc current.
As a Suction Stabilizer Back to Top
There are instances where pulsations on the suction side of a reciprocating pump can cause the same problems with vibration and hammer seen on the discharge side. More often, though, the problem is one of partial or complete cavitation. A little known phenomenum called acceleration head relates directly to the acceleration of fluid velocity on each stroke of the pump, a factor not seen in laminar flows with rotary PD pumps and centrifugal pumps. Suction Stabilizers can be sized to recover up to 95% of acceleration head losses and can easily make the difference where NPSHR is concerned. Regardless, it is a parameter which every specifying engineer is obliged to check when applying a reciprocating PD pump.
As a Surge Absorber Back to Top
Piping systems often present themselves with pressure problems, either because of rapid closing valves in the system or by pump start-up or shut-down when a corresponding change in velocity introduces a rapid pressure rise. Besides the nuisance of pipe hammer, these surges can cause considerable damage, not the least of which are line breaks and leaking flanges. Easy to solve for, surge absorbers take into account system pressures, volumes, acoustic velocities, and flow regimes.
As Thermal Expansion Compensators Back to Top
A volume of liquid trapped in an enclosed piping system has the potential to expand with a corresponding rise in ambient temperature. Some liquids more than others have high coefficients of expansion and are particularly sensitive even to small temperature changes. Liquid hydrocarbons and derivatives thereof are the best examples. Volumetric expansion in an enclosed system necessarily means that the pressure in that line must also rise, exponentially!
Considering the liability, both in terms of safety and operation, rigid piping systems have to be designed with rupture disks and/or relief valves to handle these over pressure conditions when they occur. When the frequency of occurrence exceeds reason, then maintenance cost become a nuisance. Answer. Thermal Volume Expansion Compensators. Simply stated, these devices can be sized to accumulate the pre-calculated expansion volume and limit the pressure rise to a predetermined set point somewhere below that of the rupture disk. It becomes a self regulated system with only the periodic maintenance of the compensator, itself - quite a savings in many instances.
Flowguard ModelsBack to Top
DS, DP, DA, FG & HG
Bladder type units specifically designed as Pulsation Dampers which feature maintenance friendly top access for bladder removal and replacement in situ.
Standard material is 316 stainless steel, polypropylene or Alloy 20 although dampers in other materials such as Titanium, Hastelloy, Monel, Duplex Stainless Steel, PVDF and PVC are regularly manufactured. Maximum pressure available is 2500 bar (36,000 psi).
The membrane can be supplied in NBR, EPDM, FPM(B), FPM(GF), CR, ECO, CSM and IIR rubbers.
Screwed or flanged, a choice of single, twin or multiple porting is available. Many thousands of these dampers worldwide testify to the effectiveness of this simple design concept in smoothing the flow from reciprocating pumps worldwide.
FD Series
Simple construction features a solid contoured Teflon (PTFE) diaphragm with a 316 stainless steel housing as standard and the choice of screwed or welded flange connection. Housings may also be material such as Polypropylene, PVC or special alloy and twin port configurations are also available as an option.
FB Series
These Teflon (PTFE) and alloy metal bellows models offer the highest quality available in process dampers. Teflon bellows are knife cut on precision CNC machinery. Metal bellows are formed and welded in a tightly controlled proprietary manufacturing process. These units are ideal for exceptionally aggressive liquids and very high temperatures. The FB/TD features a double membrane construction with a bellows process membrane (as 'FB') and provides a unique application solution for high pressure aggressive liquids services.
FG/TD (CIP) Series
Suitable for hygienic (CIP) applications this 'transfer' damper features a unique double membrane design and has been certified to exceed the basic requirements of the EHEDG CIP test procedure. This truly hygienic answer to pulsation problems in the food, beverage & pharmaceutical industries is supplied with a choice of elastomeric membranes and a 316 stainless steel housing with polished finish option. It is also ideal for use with difficult to handle suspended solids.
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