I'm looking for a small device that I have in my imagination but I've no idea what it's called! Can anyone help?

 

I need it to seal a small (2.5 mm diameter) water pipe with pressure difference of up to 30 kPa. I need to be able to stick a needle (or small tube) in and suck out the water with a pump or syringe (not important what exactly) in order to get rid of any air bubbles in the system. It needs to stay sealed, before, during and after insertion of the needle! Similar I guess to a spors ball valve or a sports drink container. But it needs to be small (about 0.5-1 mm)!

 

I imagine a small circular stiff rubber seal split into "leaves" like a pie. When the needle goes in, these "leaves" get pushed inwards but stay sealed. It may have a medical application.

 

Does anyone know what I'm talking about? It's driving me crazy!

Rubber, just pick your thickness and use a small gauge needle.

Sounds like a septum seal (or a very small "iris port")

Rubber, just pick your thickness and use a small gauge needle.

OK, sounds promising.....but do you know a way of determining the required rubber thickness and needle gauge?

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Sounds like a septum seal (or a very small "iris port")

Ooooh, names of things that I can search for helps loads! But I still haven't really managed to find a decent explanation of exactly what septum seals or iris ports actually are and if they exist in such small sizes.....any tips?

Thanks!

OK, sounds promising.....but do you know a way of determining the required rubber thickness and needle gauge?

 

Trial and error, usually.

Would filling about a centimeter of the pipe mouth with silicone sealant work for you ?

I've heard of people using a silicone sealant solutions for something like that