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Products  |  Fluid Mechanics  |  Examples of Transient Flow  |  HM 156
HM 156 Water Hammers and Surge Chamber Show data sheet (pdf file) Print page
Technical Description

  In water-bearing structures such as hydroelectric power stations, or in systems for supplying water, changes in flow rate such as during startup and shutdown of hydraulic machines or by opening and closing shut-off elements result in pressure fluctuations. There is a distinction to be made between rapid pressure changes that propagate with the sound velocity (water hammers) and slow pressure changes caused by mass vibrations. Pipeline systems use air vessels or surge chambers to dampen water hammers and mass vibrations.
  HM 156 is used to generate and visualise water hammers in pipes and to demonstrate how a surge chamber works. The trainer contains a pipe section with a ball valve and a surge chamber and a second pipe section with a solenoid valve.
  In the first experiment a water hammer is produced by rapidly closing the ball valve. The sudden deceleration of the water mass releases kinetic energy, which is converted into potential energy in the surge chamber. The resulting pressure vibrations are measured by a pressure sensor behind the surge chamber and displayed in the software as a pressure curve. The vibration can also be seen as oscillation of the water level in the surge chamber.
  In the second experiment a rapid closing of the solenoid valve in the second pipe section produces a strong water hammer. The water's kinetic energy is converted into pressure energy. The water hammer and the subsequent vibrations are detected by two pressure sensors in the

pipe section and displayed in the software as a pressure curve.

  The water is supplied and the flow rate measured by the supply unit.
  The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.


Learning Objectives / Experiments

- demonstrating water hammers in pipes
- determining the sound velocity in water 
- understanding how a surge chamber works
- natural frequency in the surge chamber


* Visualisation of water hammers1
* Operation of a surge chamber1
* Determining the sound velocity in water1
* GUNT software for displaying the water

  hammers and vibrations

Alternative products
HM 143 -- Transient Drainage Processes in Storage Reservoirs
HM 150.15 -- Hydraulic Ram Pumping Using Water Hammers
HM 155 -- Water Hammers in Pipes

[1] functioning of a surge chamber
[2] pipe section with ball valve and surge chamber
[3] surge chamber designed as transparent PMMA tank
[4] pressure sensor behind the water chamber for measuring the pressure wave
[5] pipe section with solenoid valve and two pressure sensors for measuring the water hammers
[6] volumetric flow measurement via supply unit
[7] representation of the pressure curves with GUNT software
[8] GUNT software for data acquisition via USB under Windows Vista or Windows 7


Technical Data

Pipe section for pressure vibrations
- copper
- L: 5.875mm, di: 26mm
- ball valve
- surge chamber, PMMA
  height: 825mm
  di: 50mm
Pipe section for water hammers
- copper
- L: 5.875mm, di: 26mm
- distance between sensors: 3.000mm
- solenoid valve, closing time: 20...30ms
Tank: 50L

Supply unit
- power consumption: 550W
- max. flow rate: 230L/min
- max. head: 11m
Tank: 1x180L, 1x40L

Measuring ranges
- pressure (pipe section): 2x 0...16bar abs.
- pressure (surge chamber):  0...0,3bar


Dimensions and Weight
LxWxH: 6.800x800x2.050mm (total)
Weight: approx. 196kg
Required for Operation
230V, 50/60Hz, 1 phase or 120V, 60Hz/CSA, 1 phase
Scope of Delivery
1 trainer with supply unit
1 CD with GUNT software
1 set of instructional material
Order Details

070.15600  HM 156  Water Hammers and Surge


© 2005 G.U.N.T. Gerätebau GmbH