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A science question


BSJ

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OK, not strictly a motorcycle problem but anyone that has had a blocked gas tank breather will relate.

I have a 5 litre plastic milk container full of water. I punch a 1.2mm hole in the lid, put the lid back on and then invert the container so the water can escape through the 1.2mm hole.

The first half hour the water flows out at a reasonable rate. Then over the remainder of the day the flow reduces to a drip every few minutes. Today there is one drip ever hour and the vacuum in the container is sucking the container sides in.....but not allowing enough water out.

I know that I can put a pin hole in the base of the container but then the water will escape to quickly.

Q: Is there a solution? Preferably without another hole.

post-63954-0-30476300-1404215741_thumb.j post-63954-0-97626300-1404215770_thumb.j

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Put two holes in the lid, the second one has a bunch of drinking straws or a plastic tube all the way to the bottom. When you invert the container the end of the "tube" will now be at the top above the liquid and will let air into the top of the container. The water will pour out and it will be empty in an hour and a bit!

That is the science bit now you have a parts locating, supply problem!

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Vocalneal nailed it...but you don't even need the venting tube to the bottom. A "J" shaped tube would do the trick.

You can even use the same hole although I would imagine it's hard to bend something to fit inside the 1.2mm and not have it collapse...but you can use that to your advantage as a flow meter also.

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I'll experiment with that idea. Preferably, I would like to have the water escape slowly over 6 or 7 days. maybe a smaller exit hole will help!

If it is for an animal's water bowl...than not capping it but suspending it so that when a sufficient quantity has been removed the vacuum is broken and more flows out works also.

**edit**

Any reason you can't have a hose running out to wherever that just weeps the quantity you want out each day from a tap?

Edited by dave_boo
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I'll experiment with that idea. Preferably, I would like to have the water escape slowly over 6 or 7 days. maybe a smaller exit hole will help!

[/

quote]

To make the water escape slowly over a few days use the tubes or set, from a intravenous fluid bottals they have a valve on you can slow the rate right down to a drip,where it fit in to the bottal, see if you can get a good seal in to the cap with out it leaking,a rubber bung would be good.

Sie- nam-gluar in Thai ,from a local chemist.

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I dont know what your trying to achieve , but the vacuum in the container needs reducing to allow further water flow.Without adding another hole - to allow atmospheric pressure in - you could heat the vacuum to raise its pressure up to atmospheric.Slowly reducing the air / vacuum volume would also work , but this requires a "controlled" crush.

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You kind of need to tell us what you want to do for the best solution.

Knowing nothing of the goal; put a valve in the top and bottom and you control water and airflow.

Pressure check valves might work in other scenarios.

A solar timer on a water outlet works for my plants.

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Knowing nothing of the goal; put a valve in the top and bottom and you control water and airflow.

Get an aquarium valve like below which can be found easily for a few baht and use it as a bleeder valve at the top of the jug. Allows you to control the amount of air getting in. Could put a 2nd one in as ttakata mentioned at the bottom also.

aquarium_air_valve.jpg

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Go to Fascino and buy one of those sliders they put on serum tubes, so you can control the flow.

Lots of good responses, thanks folks.

Jesse Frank has a good idea. All I need is a pinhole in the top and it's all good!

Dave_boo's dripper hose idea is good....but I would only need a 2 metre length!

What I am doing is setting up a watering system for my tomato plants. I have several different Australian varieties I am trialling to see which one is able to grow well here in LOS. In the new year we will be full time in the village and I would like my wife to grow a cash crop that can provide her with an income. Weather conditions aren't all that different to parts of Oz.

As we will be 4 weeks in Pattaya and 2 weeks in the village for the rest of the year I need a simple system for watering.

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Another option would be to use a wick out of the open top of the water container. Your flow I suspect would be constant. You would need to experiment with differant materials to make your wick to get the desired flow rate but it would work.

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If it is for plant irrigation then use clear small aquarium hose and use a sewing needle at each plant to prick a small hole where you need water. Use the green valve to let the air in. But the rate of flow will decrease as the level in the bottle decreases as the pressure (head) will change. The problem with using the green valves to control the air in and thus water out is that the bottle will still collapse until the vacuum developed starts to be effected by the valve bleeding air in.

If using one bottle per plant use the little green valve in the cap and one pushed through a small hole in the side near the bottom. Use the one in the cap to control the flow. It never need to be reset once "dialed in" because when you refill as it comes off with the cap. The one in the side near the bottom lets air in but is closed when refilling and still allow the bottle to rest on its base. These green vales as has been said are cheap and available anywhere they sell goldfish or aquarium equipment.

OR go to Thai Watsadu as they have drip feed irrigation stuff including valves and hose and.....

Here is some of the stuff they have.http://www.superproducts.co.th/English/Dripper/Dripper.html

Edited by VocalNeal
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In Homeworks this afternoon and I discovered they have timers! I have been to the water bits section before and not seen them. I am leaning towards a timer with hose and drippers. The idea of using a sealed container just won't fly as the amount of water per day will exceed the containers total volume even if I modify it with the green fitting. Then there's the problem of keeping them in the right position so the thing doesn't wobble around in the wind. Hose and drippers maybe the answer!

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I use these and they work OK.

http://www.ebay.com/itm/T120-Greneds-Electronic-Water-Timer-Solar-Charge-RainStop-1Year-Warranty-/181280466530?pt=LH_DefaultDomain_0&var=&hash=item2a35286662

I have't had to hand water my plants in 8 months.

Only problem is I used cheap hose disconnects and they cracked so water was flowing out on the input side.

No fault with the timer itself but make sure you use sturdy fittings.

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I use these and they work OK.

http://www.ebay.com/itm/T120-Greneds-Electronic-Water-Timer-Solar-Charge-RainStop-1Year-Warranty-/181280466530?pt=LH_DefaultDomain_0&var=&hash=item2a35286662

I have't had to hand water my plants in 8 months.

Only problem is I used cheap hose disconnects and they cracked so water was flowing out on the input side.

No fault with the timer itself but make sure you use sturdy fittings.

Similar are sold in Homeworks....I found out yesterday.....900 baht. True Value have one with 2 outlets.....4650 baht!

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BSJ,

Super Products has everything you need. That may even be what you found in Homeworks, if not Thai Watsadu.

http://www.superproducts.co.th/English/Valve/nelson%20valve.html

tttakata. A timer like yours is also locally available from Thai Watsadu.

I didn't see those ones, in the link, when I was in Thai Watsadu the other day! Homeworks and Thai Watsadu are owned by the same people so I would imagine there is some overlap in their ranges.

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I use these and they work OK.

http://www.ebay.com/itm/T120-Greneds-Electronic-Water-Timer-Solar-Charge-RainStop-1Year-Warranty-/181280466530?pt=LH_DefaultDomain_0&var=&hash=item2a35286662

I have't had to hand water my plants in 8 months.

Only problem is I used cheap hose disconnects and they cracked so water was flowing out on the input side.

No fault with the timer itself but make sure you use sturdy fittings.

Similar are sold in Homeworks....I found out yesterday.....900 baht. True Value have one with 2 outlets.....4650 baht!

2x900 sounds better than 1x4650 and twice the capacity as well!

And they have the audacity to call it "true value" :-)

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I use these and they work OK.

http://www.ebay.com/itm/T120-Greneds-Electronic-Water-Timer-Solar-Charge-RainStop-1Year-Warranty-/181280466530?pt=LH_DefaultDomain_0&var=&hash=item2a35286662

I have't had to hand water my plants in 8 months.

Only problem is I used cheap hose disconnects and they cracked so water was flowing out on the input side.

No fault with the timer itself but make sure you use sturdy fittings.

Similar are sold in Homeworks....I found out yesterday.....900 baht. True Value have one with 2 outlets.....4650 baht!
900 bart .either I am Kee-neeoo,meane that sounds expensive,a 25 LT drum ,from my local market / re-cycling center no more than90 bart ,layed on its side your aquarium valve glued in to the lid, pin prick hole in the side as a vent of the drum job done.

Did think the syphon idea good.simple and cheap,use the tube/valve from a IVF set, water would last a week.

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I use these and they work OK.

http://www.ebay.com/itm/T120-Greneds-Electronic-Water-Timer-Solar-Charge-RainStop-1Year-Warranty-/181280466530?pt=LH_DefaultDomain_0&var=&hash=item2a35286662

I have't had to hand water my plants in 8 months.

Only problem is I used cheap hose disconnects and they cracked so water was flowing out on the input side.

No fault with the timer itself but make sure you use sturdy fittings.

Similar are sold in Homeworks....I found out yesterday.....900 baht. True Value have one with 2 outlets.....4650 baht!

2x900 sounds better than 1x4650 and twice the capacity as well!

And they have the audacity to call it "true value" :-)

"And they have the audacity to call it "true value" :-)" I know what your saying! Just about everything is OTT with pricing there.

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900 bart .either I am Kee-neeoo,meane that sounds expensive,a 25 LT drum ,from my local market / re-cycling center no more than90 bart ,layed on its side your aquarium valve glued in to the lid, pin prick hole in the side as a vent of the drum job done.

Did think the syphon idea good.simple and cheap,use the tube/valve from a IVF set, water would last a week.

We seem to have our wires crossed. The timers are 900 baht and the 25L plastic drums are, as you say, about 90 baht.

I don't really want to buy a timer cos after my tooing and frowing up to the village I will probably not need to use it again! If it turns out Western style tomatoes are the go I will put in a proper sprinker or dripper system.

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BSJ,

Super Products has everything you need. That may even be what you found in Homeworks, if not Thai Watsadu.

http://www.superproducts.co.th/English/Valve/nelson%20valve.html

tttakata. A timer like yours is also locally available from Thai Watsadu.

I didn't see those ones, in the link, when I was in Thai Watsadu the other day! Homeworks and Thai Watsadu are owned by the same people so I would imagine there is some overlap in their ranges.

Everything from Super products is available at Global house or can be bought onlie http://www.itec.co.th/.

If you have the right drippers, from which global house also has a large assortment, I don't think you would need a timer.

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