How does the volumetric tube work with the plunger on a hydraulic bench?

[Naumaan]

Hi guys,
hope all are fine. i m new here and don't know much about the rules.
well according to the question i have, i thought its the right place.
i ll never mind if it is moved.
anyways
today i studied the simple laboratory hydraulic bench...
i got struck in the part where plunger is used to stop the flow of water to the sump and the volumetric tube measures the volume
i can't understand the construction and working of volumetric tube with plunger in connection...i have wasted many hours on this but couldn't figure it out
pleasezz help me ....anyone

 

[Naumaan]

the figure of the bench i mtalking about is shown in the following link
http://www.sut.ac.th/cste/Oldweb/tools/itl/me/fm/bench.jpg
dont know how to attach a picture

 

[FredGarvin]

Since this picture is taking forever and a day to load, can you be a bit more specific on what you are doing on the bench? What is your experiment about?

 

[fsshaheen]

tell me about the hydarulic bench for fluid dynamics