[TheForge] Press vs Power hammer

[Ralph Sproul]

Justin,

What you'd like to do accomplish with a press is to come and go rather
quickly at 1-2" per second, and when the real work needs done you shift down
to 1/4-1/2" per second.

This is accomplished by a two stage pump.  As an example with a 5" cylinder
you'd come and go at about 9-10 tons coming from the larger section of the
two stage pump(at the 1-2" speed), but when the hydraulic system meets with
some resistance/work/load - the smaller section of the pump provides the
2500 psi at a reduced rate of flow to yeild the 1/4-1/2 inch per second of
travel at the systems full pressure.  As soon as you head back out of the
material - the first stage of the pump comes on line again and your
traveling away at 1-2 inches per second again.

Two Stage Pumps are sold in sizes such as 16/4.   This is the pumps rated
volume in gallons per minute for a log splitter which is most likely run by
a gas engine that governs out at 3600 rpm like a faster speed electric motor
would do.   So with this 3600 rpm motor (gas or electric) you get the rated
gallons per minute.

Selecting a 1750 motor - you are cutting the volume in half, but pretty much
keeping the pressure the same as that is determined by the pressure relief
valve safety valve in the system.  This is sometimes found in the valve body
as an adjustable setting or it can be a seperate valve..........but there
must be one for oil to flow somewhere when limits are reached - or the
weakest component breaks.

So your question below is really 2" per second not minute.........and tonage
is about 10 on the large section and 25 with the small section.

You might not have been aware of the two different pressures........as this
is how a two stage pump works.

Ralph

----- Original Message -----
From: "Justin Fellenz" <sunironworks at yahoo.com>
To: "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Friday, January 21, 2005 8:59 AM
Subject: Re: [TheForge] Press vs Power hammer


> So here's a good question...when looking for a press, we know we need
> speed, both (I assume) unladen and under load. Someone said 2" per
> minute, I think. But how much pressure? 10-ton? 20, 50, 100? Is more
> better?
>
> Thanks,
>
> JRF
>
> we
> > used his 20,000 pound hydraulic press built (and sold) by Jeff
> > Carlisle.
> _______________________________________________
> Manage membership or unsubscribe at:
> http://mailman.qth.net/mailman/listinfo/theforge
> theforge mail list group photo site is
> http://www.photoaccess.com
> Login:  blacksmithblacksmith at hotmail.com
> password:  anvil
> ___________
>
>