What¦s the best possible air valve to be installed on a basketball?

[Felipe28]

The basketballs are not for playing but for engineering purposes and they need to lose as little air as possible. My concern is that the usual valves used in these balls are not that good in preventing the air leaking. Can another valve, like tire valves, be installed in a ball when it is manufactured?

 

[Ron]

The valve used for inflating sports equipment has to be as unobtrusive as possible, to prevent an influence on the performance of the equipment. The "flap valve"currently used, works well and does not appreciably affect the performance of the ball. Putting a specific by-pass valve, like that found in a tire, would probably affect the performance or use of the ball.

 

[cloa]

The question for Felipe is how these balls will be used?- anything like a normal basketball is therefore not a good idea.

 

[EngineerTex]

Air likely escapes through the wall of the basketball as much as it escapes through the valve. I would imagine that deflation occurs quite a bit through penetration of the rubber.

However, if you fill it with pure argon (check a welding shop), the larger size of the atom could potentially cut down on that somewhat. Also, argon is inert and will not react with various hydrocarbons which are going to be impossible to remove from the material in of the ball itself. These reactions will produce products which may or may not be as dense as the air in the ball.

And if you're worried about the valve, then fill it as much as you can with rubber cement -- that may involve having to drill out the valve a small amount to get an appreciable amount of cement inside with an air surface for it to cure. Or apply the cement via a (relatively) large-gauge hypodermic needle.

Engineering is not the science behind building. It is the science behind not building.

 

[Felipe28]

Ron and Cloa: the balls will be put inside a pressure vessel aonnected to a pump system and then the water inside (surrounding thee balls) will of course get the pump pressure. When an event called water-hammer occurs the pressure wil go down violently and then go up after some seconds, and so forth. Therefore the balls will suffer an expansion and contractions of their volume, acting as a buffer against these pressure variations, protecting the pipe as a consequence. In this event, the balls lose part of their inflating pressure and that´s why I want to attack the valve first. So you know now that the purpose is not bouncing them, still have some ideas about the valves?

 

[Felipe28]

EngineerTex, so far haven´t thought about changing the gas, but will check upon it. Your procedure with rubber cment sounds original. The rubber cement is a good isolating material then, right? Don´t know if I can push the valve, probably could damage ut, bit could put a bit on it. I am testing with bicycle patches, which have reduced the loss but not totally. As you say, part of the air also escapes through the material and I am contacting INMAT because they seem to have very interesting nanocomposites for coating.

 

[IRstuff]

A simple Shrader valve with a metal stem cap?

TTFN

FAQ731-376

 

[Ron]

ET's idea of the rubber cement is good, provided it doesn't attack the bladder or the valve. I believe that basketball bladders are EPDM material. There are tire puncture additives that you can spray into the ball that will serve the same purpose, but are formulated for similar materials. Check their compatibility.

Another possibility, although more expensive, is to use inflatable pipe plugs. These come in various sizes and shapes. Here's a link to one...

http://thepipeplug.com/InflatablePressurePlugs.htm

 

[MadMango]

You might also want to consider switching over to professional grade soccer balls. Their construction is different from basketballs, and many are advertised with "air tight" butyl bladders and 4-ply outer wall construction. Same inflation valves I suspect.

"Art without engineering is dreaming; Engineering without art is calculating."

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[rb1957]

of course, if you fill the valve with glue, you won't be able to recharge the ball (to replace the gas leaking through the shell).

is this for a prototype or a production app ?

you want the balls to absorb the pressure pulse in the fluid, yes ? then size, shell elasticity, internal pressure might be variables you might want to investigate ... basket balls sounds like grabbing something near-to-hand rather than something designed for the job.

 

[TheTick]

Using a consumer product (a toy!) with no traceable QA in an industrial setting? You are bound to have more problems than just air valves.

 

[MiketheEngineer]

You might try the "Flat Fixer" sold in most automotive stores. Basically shoots some kind of sealant in with air or some other gas. Seems to work pretty well on my wheelbarrows, carts, etc. which used to run flat all the time.

ONCE you use it - be careful. There is usually a warning on the label about this. I think they may use a flammable gas??

 

[Felipe28]

rb1957 and TheTick: the balls are specially made for our application, they are not the basketball you buy on a store, which don´t withstand too much inflating pressure. These balls resist more than 100 psi of inflating pressure. As good as they might be, still there is a 5-15% air pressure loss with the time, and that´s why I am trying to improve this ball to prevent problems in the future, even though a checking could be made from tiem to time to recalibrate the balls.

Size is not relevant, we simulate the water-hammer and determine how much air volume do we need and then divide it per the balls volume and obtain the number of balls necessary.

Some helps about the valve is welcome

 

[Felipe28]

IRStuff: like a bicycle valve you mean? So, your opinion is that those valves are better for isolating the air? Any idea why?

Ron: I saw the page but couldn´t figure out exactly how it works. Cold you give me an idea?

 

[rb1957]

if they're purpose built balls, why not specify a leakage rate that the manufacturer has to meet ?

what sort of pressure are we talking about 10psi ? 1000psi ??

bicycle tyre valves, Presta valves, have a locking feature that should be superior to a typical "basketball" valve.

 

[IRstuff]

Schrader valves are used for a variety of applications, including tires, RO water reservoirs, aircraft hydraulic systems, and even moderately sealed semi-hermetic applications. To get full benefit, however, you do need to use a metal cap. This results in two compressed rubber interfaces in the leak path, and the inner seal is heald in place by the internal pressurization.

Most RO water reservoirs, with admittedly low psig values, last fot years without recharging.

TTFN

FAQ731-376

 

[Felipe28]

rb1957, because they are just ball manufacturers. We ask them for a special ball but they have no idea about water-hammer and don´t have the equipment to test them. As long as we can test them and then tell the fabric to innovate according to our results, that works.

IRstuff, I see your point. I suppose the Schrader company is the best option then? Only thing that remains to be seen is if it can be installed in basket-ball type of ball.

 

[rb1957]

ok, they make the balls .... surely they have different sorts of valves ? if they're used to making basketballs, then maybe they naturally think of flush valves; but you don't mind if the valve stem protudes ... do you ?

how much leakage are you experiencing ? what pressure do you inflate the balls to ? if the leakage is significant, then either you're trying to hold a very accurate pressure or you're trying to hold a very high pressure ??

 

[IRstuff]

Should actually be pretty easy to test anyway. You could cut one out of a bicycle tube and glue the small part of the bicycle tube to the inside of the ball.

TTFN

FAQ731-376

 

[KENAT]

Given the application, is a protruding valve a good idea?

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