[TheForge] Krause/Nazel type air hammer

[theforge@mailman.qth.net]

>>
>>I think spool valves come up in the context of people wanting an option 
>>to machining their own (i.e. something they can buy).
>>
>>Steve Smith
>>
_____________

steve,

spool valves came up in mark krauses booklet. after mark made "THE VALVE" he said...

"it was later that i thought of a linear solution to these valves that would require less machining"...and later he says.."how about a pair of linear valves?". he then has a drawing of a three way spool type valve and a couple of ideas on how to make these valves. 

i have posted a rudimentary drawing (mine) of my understanding (incomplete) of how this air circuit works. to the extent that i do understand it is because of bob smolems help. any mistakes are mine. also i encourage everyone to buy marks booklet. it's good place to start.

comments welcome.

bob (no expert)

drawing is at the photo access site (url below) in the powerhammer file. 

i re read this several times and tried to make it as clear as i could but well...you know.

    

1.turn on

2. pump cylinder goes up and pushes all the air in it out thru the open exhaust port in the top three way valve.

as the pump cylinder reaches the top of it's stroke the "bottom balance valve" opens and air is drawn into the pump cylinder. (balance valves are machined into both ends of the pc rod).

3.pump cylinder goes down pushing all the air in it thru the exhaust port of the bottom valve. this air continues thru the one way valve (check valve) to the bottom of the hammer cylinder which raises the hammer.

4. at idle this cycle continues. the hammer is pushed up by the downstroke of the pump cylinder. the hammer then falls due to gravity. puff fall puff fall etc.

5.to run...both valves are actuated (pulled down in this case) simultaneously. as the exhaust port in each valve starts to close the ports in each valve leading to the top and bottom of the hammer cylinder are opened a corresponding amount. as the valves are opened further the stroke (and force) of the hammer increases.

at the bottom of it's stroke the pump clyinder is opened thru the balance valve on top to draw in air for the next power stroke.

6. the check valve allows the air of the falling pc to raise the hammer cylinder but keeps the rising pump cylinder from sucking the hammer back down.