Mailing List Archive Mailing List Archive
Hi all, I'm going to wade into this thread after a little study of my own. This is going to be a bit technical but I'll try to keep it simple. Ok, here it goes. The different designs have different strengths in different areas. The primary forces involved in a 1st stage failure come from two things....shear force(like whacking it on an overhang/dropping it) and from shear stress (caused by an axial load, and acting 45 degrees to that load). The main plus of a yoke (standard around where I am) is that it has two good-sized chunks of metal holding the thing together (the ones that go around the valve). These are very good at resisting shear force. You can whack a yoke pretty good before it'll fail. Unfortuneately, these same two pieces are not as resistant to shear stress. The axial load from the pressure from the tank acting on the 1st stage develops a significant shear stress in the metal. This wants to fracture the metal pieces at a 45 degree angle...not too much work to do. DIN connections shine when it comes to shear stress because, with the 45 degree rotation from axila load to shear stress, it must break throught more metal. To get a picture of this, think of a paper towel tube as a DIN...the seam is what would need to be broken for this type failure to occur. But, as we all know, it is easier to fold that paper tube than a good piece of cardboard. The DINs are not as resistant to shear force because of their thin tube construction. In other words, if you want higher pressures/more air use the DIN, but if you need something to take a good deal of abuse, choose the yoke. I hope this came through clearly, if not, please e-mail me and I'll try and clarify things. Mike The University of Alberta Scuba Club Tekkie
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]