Liters/min flow on a water valve

Since you have the valve, can you tell us the Cv?

What formula do you have in mind ?

I'll check the valve Cv.

Thank you

I don't have the answer, but I am anxious to see the formula.

One thing that I think would influance this answer is the speed that the valve opens/closes. How is it actuated?

Quite difficult answer with such input.

The opening time (2,5 sec.) is too short. It's the total time from closed position to closed position? the time is fully open? Think that even a fast acting valve don't stroke instanstaneously, and the opening/closing time during which the flow section is variable has in this case a significant influence.

You need as already asked the valve Cv because diameter given is (I think) nominal and not the flow depends on the type of valve (globe, diaphragm, needle,....) and furthermore, the flowrate depends on the differential pressure, not just the absolute (3 bar).

Whith the short time and small size given, if you havn't all this data available, Just measure it! Just put a bucket downstream of valve, wait for a complete actuation and measure the volume (or weight) the water.

Kind regards

Suppose the liquid comes to full flow without delay than the answer is simple. But if you have to take time delay into account I suggest you simply do a qutitative test take a continer, say 55gal barrel will do, open the valve and measure.

1½" valve, at 45psi steady stream under 3bar pressure will give you 451gpm. It will give you approximately 19gpm that is 71L/sec.

Wangito.

Gracias for your comment Wangito,

What was the formula you used ?

With more time I'm going to do the bucket test.

I used engineering tables. (Flow through a nozzle) No formula mentioned. I guess you can do the reverse math if I send you the whole table. let me have your e-mail, I I'll scan it for you. (you can do that through a private massage if you don't want to disclose it here)

Wangito.

how do you get 451gpm and 19gpm?

thank you

451gpm divided by 60 gives you 7.5 gal/sec, the answer times 2.5=18.8

US Gallon=3.78Liter

Rounded up to 19gpm times 3,78=71,8L/Sec.

Is this OK?

Wangito.

Hi Sal,

The problem is the Cv of the valve, it is different for different valve types and different manufacturer. Usually valve manufacturer use to type test its valves to determine that flow coefficient (Cv). If you know the type and make, some manufacturers have their Cv available in their websites if you don't have any documentation of the specific valve.

Anyway, the formula to determine the flow rate is the following:

Kind regards

This (Cv) will give me the max flow rate, isn't it ?

it's a Schubert & Salzer 7010 angle seat valve. Doesn't say the Cv on the technical data, but i'll see if I can find serial number.

Yes, I've googling a bit and you have a website of manufacturer. I've been reading the data sheet of your valve but there's no indication of Cv.

Nevertheless, they have a free software for sizing valves (you must select your model).

Here's the link (you have to free register to download the software)

http://www.schubertsalzerinc.com/Sizing/Software/

Kind regards