Talk:Four-way valve

Diagram wrong?

Does flipping the valve really reverse the flow in parts of the system? Diagram at top has the north port as out-flow and south port as in-flow but diagram below has them the other way around. I've usually used this type of valve to isolate part of a full system into its own closed loop (and the description that sounds like an off-line sampling region supports that). I would think the flow should instead be (pardon the ASCII-art!):

       ^ D                    ^ D
       |                      |
   +-------+              +-------+
   |   |   |              |   |   |
A  |   \   |           A  |   /   |
-->|--\ \--|<--        -->|--/ /--|<--
   |   \   |  C           |   /   |  C
   |   |   |              |   |   |
   +-------+              +-------+
       |                      |
     B v                    B v

Where B→C would be the sampling region in the A→D main flow that can be taken off-line into a private loop. DMacks (talk) 19:51, 5 March 2009 (UTC)[reply]

No. I created this article to describe and illustrate the type of steam distribution valve used by Trevithick. The diagram is correct for that application. If you want to extend it to include something else then I suggest you do that as a sub-section. In principal, the flow between connected ports will go from high pressure to low pressure, whichever way that is. Globbet (talk) 10:24, 13 June 2009 (UTC)[reply]

I agree with the question of DMacks: the picture is confusing; I'd expect the ascii configuration. I would suggest that the answer of Globbet is somehow included in the article, possibly by adding the high/low pressure info in the picture. Dvh369 (talk) 09:00, 21 September 2011 (UTC)[reply]