How the leak in a rectangular type plastic container can be determined..Does there are any methods to calculate that, viz..concepts or formula?? which i need also drop value i.e. leak rate from the container.
Please suggest me regarding this topic.
Dear Karthik,
Assuming that the item that is leaking is liquid, the velocity of the leak will be
v= sqrt (2*g*h), if you know the area(A) of the opening thru which the fluid leaks, then
Q = v * A., If you want to consider the viscosity, use Darcys formula
Dear pramod,thanks for your reply. But we don't know actually where the leak lies and with what dimensions. So how can we use that formula.
You will have to refer to past data ( location and size ) if it pertains to the failure of batteries. I hope your company maintains field failure data
Hello Karthik
you can use a small air compressor, a flow meter, a needle valve, a pressure gauge and a soap bottle
Blow the air into the container and make sure that you maintain the pressure to less than one inch of water water column or less than 25mm of water column in the tank if this is not a pressure tank. once you have achieve a stable pressure you will have your flow rate with air from the flow meter.
Use the soap and water bottle an start spraying the box. where you see bubble coming out you will have your leaks.
You can do the same with water and fill out the box but make sure you control the internal pressure because square box are not very good at holding pressure without deforming.
Good luck.
Thanks Mr.Gilles brule. We can find whether there is leak or not as per your procedure.
But my concern is about leak rate. How much amount of gas or fluid is passing through that hole if any???
Dear Karthik,
In addition to what Gilles Brule has suggested ,you can seal the container after you fill it with known pressure of gas, from the leak therr will be drop in pressure, can;t the gas laws be used to find the leak rate.For liquid also you can do the same, seal the gas above the liquid surface, drop in gas pressure will give you the leak rate , alternatively you can collect the leaked fluid in a jar and measure it physically.
Hello
You get the leak rate (volume flow rate) by recording it from the air flow meter in litre per minutes. These are inexpensive and calibrate. Using this you do not have to do any calculation since you have the actual leakage. Once you have the stable/constant pressure in the box, the air going in = the air going out. Because you have the pressure and temperature you can check the change in density and get your mass flow rate.
You could also get a mass flow meter which is very accurate and very expensive if you need the accuracy of experimentation.
Dear Mr Gilles / Mr Karthik,
I feel that adjusting the flow rate to maintain constant pressure will consume a lot of time, it would be easy to start with a known pressure in a known enclosed volume and monitor the pressure drop over a period of time. The calculation for the leak volume can be done from the time, pressure and volume readings taken during the experiment.
Dear Pramod
You do not adjust the pressure, you let the pressure build up to a constant and stable within the physical limit of your box, then you take the measurement by reading the flow meter. At this point you know exactly rate of leakage. it should take you no more than 10 minutes unless your box has a volume of a few 100's meter cube. You can then calculate the flow rate with different pressure in the box or do a few more test and establish a curve and compare it to the calculated/theoretical value.
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