Pulsation Dampeners and Surge Alleviators for Hot and Cold Liquids

Pulsation dampeners and surge alleviators for hot and cold liquids, and liquids which are not compatible with PTFE or an elastomer.

Thermal Expansion and Contraction Compensation

A liquid in a closed system begins to expand when its temperature rises, and causes an increase of pressure in the system. Depending upon the thermal expansion coefficient of the fluid, this expansion in volume can lead to dramatic positive pressure in the system. In consequence, leakages at flanges and connections, as well as pipe swelling occurs.

Generally, for the protection of systems in such cases, relief valves or bursting discs are isolated, despite all their disadvantages. Relief valves do not refill the system after releasing back to the correct setting, Leakages lead to system shut-down and both leakages and relief valves may require expensive return pipes to catch the overflow and return it to the supply tank. If the temperature decreases again the flange gaskets and seals will be sucked in by negative pressure.

On the other hand, the installation of a thermal expansion compensator is todays way of addressing these problems. For closed systems, because the system remains closed.

With temperature rise the thermal expansion compensator takes up the expansion volume of the liquid caused by temperature rise to itself - when the temperature falls again the compensator keeps the system re-filled.

The volume of a thermal expansion compensator is calculated by using the thermal expansion coefficient of the liquid, for the maximum temperature rise that is expected, and for the total volume of the enclosed liquid, and the maximum permitted pressure increase and decrease.

A thermal expansion compensator has an elastomer bladder, a ptfe diaphragm, or a metal membrane, depending upon chemical compatibility and suitability for temperature. The membrane is chosen by the cost considerations for the liquid compatibility and temperature in question, according to the volume of compressible gas that is needed.

The expansion and contraction of the pipe material itself, also tends to compensate for the need for volume to change without dramatic pressure variation. Generally, the practice is to ignore this benefit simply to have it as an additional safety factor.

These compensating devices, when the system is not locked in, also help to: absorb any water hammer, act as attenuators for pressure shocks, and address start-up surge from the pump.

Pressure Compensation for Volume Expansion or Contraction Due to Temperature Change

Where block valves shut a volume in a pipe that may be subject to temperature change and where a relief valve piped back to source is not safe or practical, FlexOrber or LiquiBello volume compensators are used. The LiquiBello Metal Bellows bellows capsule is replacable. FlexOrbers have PTFE Diaphragms from FlexFlon or virgin Teflon (El DuPont).

1. Reservoir, 2. Centrifugal Pump, 3. Motorized progressice Valve, 4. Vacuum Breaker, 5 Centrifugal Pump2. Centrifugal Pump2. Centrifugal Pumpvv 10. SurgeGuard 11. Emergency fast shut down valve

We can provide you with the pulse dampening or surge alleviating device required to meet your particular systems temperature expansion / contraction compensation and membrane permeability requirements. Jacketed pulsation dampeners may be provided with removable thermal jackets for better cleaning, or with non removable welded jacketing that remains part of the pulsation dampener shell. Membrane permeability, for use with carbon dioxide (CO2) in gas or liquid form, and liquid nitrogen, resloved through the use of a metal membrane.

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Pulsation Dampener / Pulsation Dampener Drawings / Pulsation Dampener Safety

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