jayjay

Thanks for the answers! I understand that a valve will not adjust the pressure, yet if the opening where the water exits is located at the bottom of the container (it is not possible in this project to use height to add constant pressure as in an intravenous, not is it possible to change the location of the spout), and the container is full of water, say with 500g, then the pressure into the exit when pouring will be greater than when there is only 50g of water left in the container... right? or am I still misunderstanding? Since in a container like this one, http://www.pernellgerver.com/hawshandywateringcan.htm ,the more liquid is in the container, the higher the depth of water. Right? (assuming only atmospheric pressure is present). In my container, the spout is at the bottom, and the base has a diameter of about 20cm, and then tapers increasingly to about 10cm diameter at the top.

This is for a hobby project. Normally in this application, one uses a scale to measure the liquid poured in a certain time frame. But I'd like to eliminate the scale and instead use only time and a precise flow restrictor which can be adjusted to pour a certain amount of liquid in a given time. I'm thinking something like this: http://apps.boschrexroth.com/products/compact-hydraulics/Sleeve-Catalog/pdf/RDF.pdf But this project will only work if the flow rate remains constant regardless of volume inside the container. So if I begin with 500g of liquid, or 250g of liquid, the flow rate will remain (relatively) constant. Obviously there will be some decrease in flow depending on the weight pressure, but will it be appreciable? Thanks again! You're great! J

Thanks for the answer, Captainpanic! Think of a watering can for plants- long and thin spout coming out from the bottom of the container, with an opening at the top for filling (ie no suction). I want to install a flow restrictor onto the end of the spout to adjust flow rate incrementally in order to pour a certain amount of water per minute. Say for example, 125g/minute. I would like it to be quite accurate, and therefore I'd like to know how much the initial volume inside the can would affect the flow rate with said flow restrictor installed. I've tried to test how much I can pour in 10 seconds with a full can vs a half full can, but it's altogether too inaccurate, thus my post here with the science folks. I really appreciate your help! J

Hello, Obviously I'm not a science person, but I have a question that one of you geniuses can probably help me with- say you had a container with a thin gooseneck spout (about .5cm diameter) that restricted the pouring flow rate of water out of the container, would the initial amount of water in the container affect the flow rate? if so, what if you were dealing with only 250g or 700g of water in the container, for example- would the flow rate change significantly between these two initial amounts? how much would the flow rate decrease as the volume inside the container decreased? I'd like to know if the time it takes per gram of water to be poured will be affected very much by the volume inside the container. obviously the pressure would be higher with more water, but would it be a significant difference with such small initial volumes? ie 200-700g Thanks so much in advance!