View Full Version : Multiple Expansion Valves

06-02-2017, 02:50 PM
Dear All,
I have a questions about Multiple expansion vales. I found this article but don't understand how they operate. From the P-H diagram you can tell that this valve operates as a flush tank but I cant find a valve that can do this at no manufacture portfolio.
Perhaps someone with more experience can help me with this.

Please find following on page 7 the information I refer to:

The other parts of my system are exactly the same including, 1 stage compressor and 2 different temperature evaporators.
Any feedback is highly appreciated.
If you have any questions please let me know.

Best regards

06-02-2017, 05:32 PM
Have you read any of the Sporlan documentation regarding expansion valves?


06-02-2017, 06:27 PM
Hi SnowKing,
As I understand it, the P-H diagram and the scheme do not match one to each other.
As point 4 is the result from flash expansion, point 5 will be equal to point 4 and not liquid at saturation as indicated in the P-H diagram.
The refrig cycle would be just like the one represented in Fig 13.2(a) &(b) - page 6.
To have a P-H diagram like the one in 13.3 you need additional equipment, for instance a separator and a pump, and the output of evaporator-II would go to that separator.
Hope that the explanation can be of some help.

10-02-2017, 05:47 PM
When you have expansion valve it means it is DX system
With 1 compressor and 2 different temp
You need kvp (evaporating pressure regulator ) in small system or PM 3 or pm 1 ( back pressure regulator ) in large system with other valves as you need
You could find more information on danfoss web.