Jun 19, 2014 When a centrifugal pump stops delivering sufficient pressure, breaks down frequently, or vibrates at high levels, it’s easy to blame the pump. Frequently system problems are misdiagnosed as pump problems because the pump is the one making the noise or underperforming. But to solve performance issues at the ground level, maintenance.
Effect of a pressure surge on a float gaugeHydraulic shock (: water hammer; fluid hammer) is a surge or wave caused when a, usually a liquid but sometimes also a gas, in motion is forced to stop or change direction suddenly; a change. This phenomenon commonly occurs when a valve closes suddenly at an end of a system, and a pressure wave propagates in the pipe.This pressure wave can cause major problems, from noise and vibration to pipe collapse. It is possible to reduce the effects of the water hammer pulses with, and other features.Rough calculations can be made either using the (Joukowsky) equation or more accurate ones using the.
Expansion joints on a steam line that have been destroyed by steam hammerSteam distribution systems may also be vulnerable to a situation similar to water hammer, known as steam hammer. In a steam system, a water hammer most often occurs when some of the steam condenses into water in a horizontal section of the piping. Steam picks up the water, forming a ', and hurls this at high velocity into a pipe fitting, creating a loud hammering noise and greatly stressing the pipe. This condition is usually caused by a poor condensate drainage strategy.Where air filled traps are used, these eventually become depleted of their trapped air over a long period through absorption into the water. This can be cured by shutting off the supply, opening taps at the highest and lowest locations to drain the system (thereby restoring air to the traps), and then closing the taps and re-opening the supply.On, a fluid hammer can take place when the throttle is closed while the turbocharger is forcing air into the engine. A placed before the throttle prevents the air from surging against the throttle body by diverting it elsewhere, thus protecting the turbocharger from pressure damage. This valve can either recirculate the air into the turbocharger's intake (recirculation valve), or it can blow the air into the atmosphere and produce the distinctive hiss-flutter of an aftermarket turbocharger.Water hammer from a jet of water If a stream of high velocity water impinges on a surface, water hammer can quickly and destroy it.
In the, the lid to a 640 MW turbine was ejected upwards, hitting the ceiling above. During the accident, the rotor was seen flying through the air, still spinning, about 3 meters above the floor. Unrestrained, 256 cubic metres (67,600 US gal) per second of water began to spray all over the generator hall. The geyser caused the structural failure of steel ceiling joists, precipitating a roof collapse around the failed turbine.Water hammer during an explosion When an explosion happens in an enclosed space, water hammer can cause the walls of the container to deform. However, it can also impart momentum to the enclosure if it is free to move.
An underwater explosion in the vessel caused the water to accelerate upwards through 2.5 feet (0.76 m) of air before it struck the vessel head at 160 feet per second (49 m/s) with a pressure of 10,000 pounds per square inch (69,000 kPa). This pressure wave caused the 26,000 pounds (12,000 kg) steel vessel to jump 9 feet 1 inch (2.77 m) into the air before it dropped into its prior location. It is imperative to perform ongoing preventative maintenance to avoid water hammer as the results of these powerful explosions have resulted in fatalities. Mitigating measures Water hammer has caused accidents and fatalities, but usually damage is limited to breakage of pipes or appendages.
An engineer should always assess the risk of a pipeline burst. Pipelines transporting hazardous liquids or gases warrant special care in design, construction, and operation. Hydroelectric power plants especially must be carefully designed and maintained because the water hammer can cause water pipes to fail catastrophically.The following characteristics may reduce or eliminate water hammer:.
Reduce the pressure of the water supply to the building by fitting a regulator. Lower fluid velocities. To keep water hammer low, pipe-sizing charts for some applications recommend flow velocity at or below 1.5 m/s (4.9 ft/s).
Fit slowly closing valves. Toilet fill valves are available in a quiet fill type that closes quietly. High pipeline pressure rating (expensive). Good pipeline control (start-up and shut-down procedures). (used in many systems) help maintain steady flow rates and trap large pressure fluctuations. Air vessels work in much the same way as water towers, but are pressurized.
They typically have an air cushion above the fluid level in the vessel, which may be regulated or separated by a bladder. Sizes of air vessels may be up to hundreds of cubic meters on large pipelines. They come in many shapes, sizes and configurations. Such vessels often are called accumulators or expansion tanks.
A similar in principle to a called a 'Water Hammer Arrestor' can be installed between the water pipe and the machine, to absorb the shock and stop the banging. Air valves often remediate low pressures at high points in the pipeline. Though effective, sometimes large numbers of air valves need be installed. These valves also allow air into the system, which is often unwanted. Shorter branch pipe lengths. Shorter lengths of straight pipe, i.e. Add elbows, expansion loops.
Water hammer is related to the speed of sound in the fluid, and elbows reduce the influences of pressure waves. Arranging the larger piping in loops that supply shorter smaller run-out pipe branches. With looped piping, lower velocity flows from both sides of a loop can serve a branch.
on a pump. Pumping station bypass.The magnitude of the pulse.