The most famous multi-function thing in the world is, without any
doubt, the Sauer Danfoss multi-function valve, used for series 90
closed loop pumps. I have already described the pumps, as well as the valves,
so I won't be touching their function in this article. What I would
like to address here is the one question I am asked every once in a
while - how to disassemble these valves?
The valve is composed of two parts - the pilot part (back) and the poppet part (front).
The pilot part of the valve can be easily
disassembled by unscrewing everything unscrewable, and taking the parts
out. Why do you want to disassemble this part? - For cleaning (the
closed volume can get quite dirty due to corrosion and contamination accumulation) and to replace the o-ring inside.
The poppet part is a bit harder to open, because the
valve's back part is pressed into the poppet sleeve, but it is still
possible if done with care, as you can see in the video.
Why do you want to open this part? - Well, you don't want to open this
part, unless you absolutely have to. The best way to deal with a
damaged multi-function valve is to replace it with a new one.
Note that in the video I am opening a muti-function
valve from a relatively small unit. Bigger ones might require a press
to press the poppet sleeve out. If you ever venture to disassemble one
of these, be very careful when putting the pieces back together - the
sleeve must enter the back part straight - otherwise it can be damaged.