Pulsation and water hammer are common occurrences in pumping systems. As common as they are however, many of our customers have questions, or don’t completely understand how these phenomenon occur, and what can be done to resolve them. We sat down with Brandon Dalrymple and Nathan Ackeret from Blacoh Fluid Control (manufacturer of pulsation dampeners, surge suppressors), and asked them to answer a few of our customers’ most common questions about water hammer and pulsation
- How can I keep my pipes from rattling? They are already tied down.
The pipe rattling can be caused by several sources, most typically from pulsation or water hammer. This type of vibration can be mitigated with a pulsation dampener or surge suppressor, depending on what is actually causing the movement.
The rattling noise can also come from mechanical movement, generated by the pump, valves, or physical movement of a device in the system. Solutions for reducing the rattling may include using isolators, vibration dampeners, and different types of valves or anchors for the equipment.
- What causes the noise associated with water hammer?
The noise is the acoustic wave created when the fluid changes velocity in one part of the system and collides with fluid travelling in a different direction at a different speed in the system.
- What’s the difference between pulsation and water hammer?
Pulsation and water hammer have similar effects on the system, but very different causes. In order to address the issues that arise with pulsation and water hammer, it’s important to understand the difference.
Pulsation: Pulsations in the system are created by the action of the pump. For example, an AODD pump or metering pump will push a volume of fluid into the system, stop, and then pump in fluid again. See the video for a great representation of this.
Water Hammer: Water hammer or hydraulic shock, is a momentary increase in pressure in a liquid handling system due to a sudden change in velocity and/or direction of the liquid flowing in the system. The name “water hammer” comes from the sound of acoustic pressure wave or transient. The sound is similar to a hammer banging on the pipe as the wave reverberates in the pipe. These pressure waves travel at the speed of sound, which in water can be as high as 4,700 feet/second, thus delivering the loud banging sound.
Surge: Surge is usually a less severe form of water hammer caused by internal pressure fluctuations in the system, a much slower oscillation of fluid.
Have even more questions about pulsation or water hammer? Ask us about it! We gladly provide technical assistance to companies in Wisconsin and Upper Michigan.