4 replies to this topic

[rikakose]

A very occasionally used pipe, DN100, around 100m, transferring some highly reactive material from the storage tank to the plant.

When it is not in use, the material will be back to the storage tank completely or partially.  When the production starts, the material needs to be dosed to the plant with accurate amount. So we need to measure the flow accurately. But we don't want to keep the pipeline full of the material, because the material is toxic and reactive.  . 

 

The flow meter will be need the plant and pump is under the storage tank, the distance is around 100 meter. So when the pump starts, the first couple of seconds, there is only air/vapor or half air/vapor pass through the flow meter. 

 

I found a new type flow meter with depth and velocity sensors which can measure partially full pipe, anyone has experience with this type of situation or this type of flow meter. 

Edited by rikakose, 21 August 2018 - 08:51 AM.

[breizh]

hi ,

Probably good if you share with us the brand , type of flow meter you found !

my 2 cents

Breizh

[thorium90]

The Krohne Tidalflux or the ABB Aquaprobe are flowmeters that do partial pipe flow measurement. But do note there is still a minimum and maximum pipe fill percentage requirement for them to be able to read anything.

Based on your description of use, I would think these are not suitable.

I would suggest just have a normal electromagnetic flowmeter installed in a vertical pipe, when the pipe starts getting filled, it will pass the flowmeter electrodes altogether at the same time, and you will get a reasonable reading immediately after the fluid surface passes the flowmeter. The flow will be sufficiently good not long after the pump starts and you will not get partial vapour/liquid at all during the pump. It will therefore be all vapour or all liquid.

If the straight length is not enough because as you mentioned, the pump is under the tank, use a flow conditioner, which is just a plate of perforated holes to straighten the flow.

Or, the last option is to have the flowmeter in the pump suction. Presumably the pump will be primed before the pump starts, so the flowmeter will definitely be fully filled when the pump starts. You will therefore get flow readings from the instant the pump starts. The pump suction is presumably sized for about 1.7m/s so this velocity is still sufficiently accurate for the purpose.

Hope these suggestions are useful.

Edited by thorium90, 22 August 2018 - 08:25 AM.

[Bobby Strain]

I would be inclined to install a separator near the user. Send vapor and liquid separately. Then you can use an accurate meter for the liquid.

 

Bobby

[rikakose]

Thanks a lot. 

 

A product from Krohne is the flow meter I found. But exactly as thorium mentioned, it has certain measuring range. 

Similar to Bobby's suggestion, we will add a dosing vessel or circulating line.