SpudFiles

well a friend of mine gave me a couple of qev's , all the cannons that i have built have been with sprinkler valves, so i don't realy know to much about them and after spending the last couple of hours searching and reading the everything i could find about them i only have one question. is there a big difference in perfomance between the different qev manufacterers? the ones i was given are 3/4 humphrey qev's and look this.

I wouldn't know that but qev's as far as i know have better performance than sprinklers so i would just use them regardless of the manufacture.And i dent really think the manufacture would make too much of a difference.

well it depends what the flow is etc. also the pilot has a big effect on opening times. However unless the designs are radically different there probably won't be much of a difference between brands.

The manufacturer has no real impact on the QEV only whether or not it was a diaphragm or piston QEV, as 'phragm QEVs has metal restrictors build into the exhaust and fill in/output.

The only other thing that might make a difference in manufacturers is the piston weight in the QEV. Obviously, the lighter the piston, the better a QEV will function.

Brands might only differ like 20% on the opening time or flow, but no more.
Its a QEV, it rocks, and you should use it!

thanks for the responses guys, i guess i'll have to come with something to use one on and try it out. especialy since i have to put my other project on hold till after christmas.

One of the nice things about QEVs is that the manufacturer often lists their flow rate on their websites, so you could probably look up your specific valve and compare it against others.