Pulsation Dampeners with EPDM, Nitrile, Fluoro etc, Elastomer Bladder (gas bag)
PipeGuard Low Pressure - For best value flow stabilization, where pressure is below 40 Bar, 600 psi and elastomer synthetic rubber is compatible, and external environment is corrosive. PipeGuard High Pressure - Medium, High, Super , & Extreme Pressure "gas Bag" Stainless Pulse dampener , with internal web stabilization. PipeGuard Plastic - Only when compatibility makes it essential. Ferric Chloride, sodium hypo chlorite, dissolved chlorines & hydrochloric acid, etc. Consider metallic support outside plastic wetted part designs.
THE DAMPENERS NAME
PipeGuards, are so named because they are not generally used for anything more than preventing sudden volume change from causing pipe shake.
THE DAMPENERS PRINCIPLE of operation.
Pulsations Dampeners typically prevent an amount of pressure pulsation from occurring."Dampeners", so called, do this service of prevention, by reducing the system resistance to flow fluctuation. Flow fluctuation reduction by Dampeners, is most accurately described as "helping to reduce acceleration head" Therefore the prevention function, of "dampeners" is solely by ACCUMULATION and DISCHARGE of volume. Really, single connection (more later) "dampeners" are just hydropneumatic ACCUMULATORS. They do not dampen anything, they accumulate peak flow volume and let it flow back out into the system when the rate of flow decreases.
When a system resists an attempted change in flow, whether the change being resisted is by: the modulation of a flow control valve, the "chattering" of a check valve, the closing of a bouncing relief valve, the closing of a block valve or even the behavior of a pump, Then, there will be a pressure increase . If there is some elasticity in the system, for example: some thin walled tube that can swell, hose that can dilate, bellows joint that can deflect, or an ACCUMULATOR that can accept the mass change, the pressure increase will be lessened. As the flow rate decreases the pressure may decrease. When the pressure decreases, the liquid energy stored, or "accumulated", by the source of the elasticity will push the volume that it has stored back out into the system. Therefore a balloon in a can, where the can is piped to the system, will be an easy way of allowing the compressibility of air or nitrogen, to accumulate additional amounts of flow, and pushing them back out into the system, This accumulation of peak flows and delivering them back out into the valleys in the flow pattern, is simply addressing flow fluctuation. Flow is rarely at greater than 15 miles per hour. So there is plenty of time for the flow to go up and down a single connection, for FLOW FLUCTUATION ACCUMULATION.
Because flow fluctuation has to go up, stop, and come back down the single connection of an accumulator, the pressure change from the flow reversal will always be pressure pulsation.
PRESSURE PULSES ARE VERY DIFFERENT FROM FLOW FLUCTUATION.
Where as flow may be at 15mph, pressure travels,in a liquid filled pipe, at 3600 mph. For example if you have a pipe that is a kilometer long, and there is a pressure change at one end you will detect it at the other end one second later. When there is pressure pulsation left in a system by, for example the use of a single connection accumulator, it will simply reverberate up and down the pipe past the single connection to an accumulator .
THEREFORE ACCUMULATORS DO NOT DAMPEN PRESSURE PULSES.
ADDRESSING PRESSURE PULSES, and also reducing acceleration head.
As the velocity of pressure is faster than the speed of a bullet, it is essential to intercept pressure pulsation. Intercepting is only possible when the pulsation has to attempt to travel through the interceptor. Therefore an "pulsation suppression device" must have at least an inlet and a separate outlet, so that it can fit in the line without any "T" which can serve as a by-pass. By definition a dampner is a flow-through device.
Because the velocity of pressure is so high, it is difficult to turn a pressure wave, it is common for reflection to occur from any change of direction point.
1. A reduction in diameter will be seen by a pressure wave as a "brick wall", it will cause a reflection. However if the included angle of a reduction in diameter is gradual, say 7 Degrees or less, then the pressure wave may be simply accelerated down the taper.
2. If the change in direction is made with a radius bend of say 10 times the pipe diameter then the pressure wave may be turned in the direction required without reflection.
3. A wave can in part be bounced round a corner by a series of 45 degree direction changes, though there will be some partial reflections.
AND one other BASIC.
If you can cause a pressure wave to enter a chamber, that is many time the diameter of the hole through which the wave is force to enter, then you may destroy the pressure wave, - dampen it- remove its energy by dissipating it, as heat.
So a Pressure Pulse Damper has by definition:
Multiple ports, at least an in and an out, plus direction changes in and out that are gradual, be other than the equivalent of 90 degree elbows. and the pulsation entry will be relatively small compared with the dampening chamber.
A BALLOON IN A CAN - CAN PREVENT TOO MUCH ACCELERATION HEAD but leaves lower amplitude pressure pulsation in the system. It also does not address any fluctuations or pulsations above 30 - 60 Hz, see below. Not only does a single connection accumulator leave pulsation in a system, but also, the membrane, the "balloon" has to be strong to be serviceable.
The response characteristics of strong membranes - gas bag balloons, liquid bladders, diaphragms, flexible hose tubes, etc generally do not exceed a 15 to 30 Hz. response without the beginning of phase lag. Some PulseGuard manufactured by Liquid Dynamics can respond up to 100Hz.
Therefore if the system piping is shorter than 30 meters or less, the acoustic frequency will be in the order of 60Hz or more, hence a membrane type accumulator - even if it has a sensitive membrane in side it, and is a flow through design, is not going to help very much with pressure pulsation or higher frequencies at all. We must therefore add to the definition of a pressure pulse damper that it is a relatively large diameter.
Volumes: 1.0 in3 / 16 ml, through 3,600 in3 / 60 Liters
Pressures: 125 psi / 8.5 Bar (plastic), through 20,000 psi/ 1,380 Bar
Connections: 1/8" / 3mm through 8 "mm / 200 mm
PipeGuard Low Pressure - For best value flow stabilization, where pressure is below 40 Bar, 600 psi and elastomer synthetic rubber is compatible, and external environment is corrosive.
PipeGuard High Pressure - Medium, High, Super , & Extreme Pressure "gas Bag" Stainless Pulse dampner , with internal web stabilization.
PipeGuard Plastic - Only when compatibility makes it essential. Ferric Chloride, sodium hypo chlorite, dissolved chlorines & hydrochloric acid, etc. Consider metallic support outside plastic wetted part designs.
See also: Suction Stabilizers