what does a hydraulic spool valve works?

[liam]

i went over the net and all the information i got did not help me to understand what is the function of it really. I cant seem to find what is it used for. Anybody out there knows anything about it and can u recommend some good sites?

[roofdoctor]

a spool valve is a sliding valve sometimes shaped like a longer cotton spool, set in a tube, it diverts the flow of liquid to various outlets , if u had one on an hydrolic ram or arm it could change or divert the oil to a different ram, another name for it is a diverter valve

[fabien]

Try http://www.howstuffworks.com/hydraulic-crane3.htm for a nice picci