Hi
would you please tell me how can I find a proper instrument for detection of reverse direction of flow in a large diameter steel pipe in side a cavern.

please be noted that in a hydro-power plant (dam) in de-watering and drainage system a final discharge steel pipe (diameter:1200mm) inside a cavern will discharge the collected water from drainage system to outside of the power house without any pump with gravity effect (all the diameter of pipe will not fill with water flow in normal case, in normal case only 20% of diameter is fill with water).

In a special case, special flood condition,the water flood with very high volume of water may attack to inside the power house in reverse direction of normal flow in above mentioned pipe.
finally, how can I find any sensor or switch which detects this reverse heavy and rapid volume of water in REVERSE direction of normal operation.(I want to find and purchase a proper and applicable reverse flow direction switch or sensor for this application).

Tanks in advance
Hamidreza Ahmadirad
[email protected]

 

I am not a fan of flow switches but here's an idea.

Use a paddle type flow switch Magnetrol or equal with a 1,200 mm paddle mounted in the top of pipe.

Or

I assume the pipe is horizontal. Suspend a piece of flat bar about 1,300 long into pipe with a pivot point at 1,100 adjacent to the pipe wall so that it swings one way for normal flow and the other way for reverse. Detect the position of the short section outside the pipe with a waterproof proximity switch.

You might need to add a target to the bottom of the bar so that the water has sufficient area to work against.

Oh, I see your e-mail and I will send a sketch.

Regards,
Roy

 

With a little engineering you should be able to use an insertion mag meter. I know of at least one meter that has forward & reverse indication along with digital alarms. The meter would have to be placed in a position such that it will see water all of the time but not where mud or other debris could build up. This would give a no moving parts solution that should be very durable unless there is too much debris in the water. Also the time response may be 1-2 seconds. Let me know if you would like further details.

John Catch
jbc at inflowinc. com

 

I would be looking at the class of meters called "surcharge" meters that work in both directions, whether the pipe is full or not. Any switch is a major failure point, since it won't operate unless it is needed, and of course, when it is needed, it won't operate.

The best of the surcharge meters are made by the Marsh-McBirney division of Danaher Hach McCrometer American Sigma Etcetera, whatever they are calling themselves today. It is called Flo-Dar. Next best is the old Badger transit time meter, that is now made by Eastech. The Flo-Dar is only best because it more easily works in very large pipes.

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