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Re: [Phys-l] size controversy

*H. *Wörner's website mentioned they make balloons suitable for both helium and hydrogen fills.
It mentioned leak rates - suggesting there is not much difference in leakage for either gas.

When I wrote to inquire about the difference in leak rates, H. Wörner replied in this way:

*******************************************************

*From:* Ballonbau Wörner GmbH [mailto:info@ballonbau.de]
*Sent:* Monday, December 07, 2009 1:28 AM
*To:* Brian Whatcott
*Subject:* AW: Leakage Rates for H and He

Dear Mr. Whatcott,

two types of standard fabric are used to build the gas balloons:

Type 1: 170 g/m², double side coated

inside: electrically conductive
outside: UV protective and light reflective
leak rate: approx. 800 – 1.200 cm³ per square meter per day at 1 bar differential pressure.

Type 2: 370 g/m², double side coated

inside: translucent coated
outside: UV protective and light reflective
leak rate: approx. 300 – 500 cm³ per square meter per day at 1 bar
differential pressure.

We hope we could help you!

Best regards
Ballonbau Wörner GmbH
M. Wörner

/**************************************************
/

/One might speculate that balloon fabrics of this kind have a fairly constant
specific leakage rate per unit area per unit pressure difference for a given lifting gas. (i.e leak rate X p.d. X area/mass)
which does not vary hugely between H2 and He
/

/Brian W
/

/ /

/ /

****************************************************************

Ballonbau Wörner GmbH

Zirbelstraße 57 c

D - 86154 Augsburg

Tel.: 0049 - 821 - 450 406 - 0; Fax: 0049 - 821 - 41 96 41

E-Mail: info@ballonbau.de <mailto:info@ballonbau.de>

Homepage: www.ballonbau.de <http://www.ballonbau.de/>



Bernard Cleyet wrote:
Yes (diffusion). The spectrum tubes have a rather short useful life compared to, say Ar or N. /snip/
On 2009, Dec 03, , at 09:26, curtis osterhoudt wrote:

Is the leakage you refer to an actual physical leakage (i.e. diffusion) of gas into or out of the tubes?
cut