Hi,
I'm a farm owner. I recently built a 20-ton hydraulic press for pushing
bushings and bearings, and for straightening bent shafting. It works
fine -- two-hand operation, a motor spool control so I can "nudge" work, and
a two-stage pump to give good ram speed with a high end pressure.

But the NOISE! It darned near drives me out of the shop!

I've bunkered the pump/tank affair with concrete blocks and earth, and with
a 2" thick drywall cover. That vastly reduced the noise coming directly
from the pump.
But the high pressure line (about 8' long), and even the press frame itself,
just "rings" LOUD at the gearotor's frequency.

I guess I'm sensitive to that sound. But if I spend a couple of hours
re-bushing an entire machine, I'm worn out from the sound.

I don't like wearing earplugs or muffs... they prevent me from hearing other
important sounds in my work environment; so I'd like to eliminate the noise
source.

My background is electronics, not hydraulics. I envision something like a
"low pass filter" (r/c network) eliminating the "ripple".

Would I be correct in assuming that an air accumulator near the pump would
eliminate this racket? Maybe that, and an oriface or flow control valve
either upwind or downwind of the accumulator? I don't want to spend the
money if it won't help.

If that's not the solution, or if there's more to it than that, I'd sure
appreciate some help.

LLoyd

It could be your hydraulic pump is cavitating. Google. If your machine
was made by a US company you might call them up and ask them if a rebuild
kit is available.

I was afraid that had happened to me on my ironworker. But then I tore
it apart and cleaned the tank meticulously and refilled it with new fluid
and now it's much quieter.

Maybe that would help you.

GWE

Lloyd E. Sponenburgh wrote:
Hi,
I'm a farm owner. I recently built a 20-ton hydraulic press for pushing
bushings and bearings, and for straightening bent shafting. It works
fine -- two-hand operation, a motor spool control so I can "nudge" work, and
a two-stage pump to give good ram speed with a high end pressure.

But the NOISE! It darned near drives me out of the shop!

I've bunkered the pump/tank affair with concrete blocks and earth, and with
a 2" thick drywall cover. That vastly reduced the noise coming directly
from the pump.
But the high pressure line (about 8' long), and even the press frame itself,
just "rings" LOUD at the gearotor's frequency.

I guess I'm sensitive to that sound. But if I spend a couple of hours
re-bushing an entire machine, I'm worn out from the sound.

I don't like wearing earplugs or muffs... they prevent me from hearing other
important sounds in my work environment; so I'd like to eliminate the noise
source.

My background is electronics, not hydraulics. I envision something like a
"low pass filter" (r/c network) eliminating the "ripple".

Would I be correct in assuming that an air accumulator near the pump would
eliminate this racket? Maybe that, and an oriface or flow control valve
either upwind or downwind of the accumulator? I don't want to spend the
money if it won't help.

If that's not the solution, or if there's more to it than that, I'd sure
appreciate some help.

LLoyd

On Thu, 06 Jan 2005 07:12:05 -0800, Grant Erwin
wrote:
Lloyd E. Sponenburgh wrote:

Hi,
I'm a farm owner. I recently built a 20-ton hydraulic press for pushing
bushings and bearings, and for straightening bent shafting. It works
fine -- two-hand operation, a motor spool control so I can "nudge" work, and
a two-stage pump to give good ram speed with a high end pressure.

But the NOISE! It darned near drives me out of the shop!

It could be your hydraulic pump is cavitating. Google. If your machine
was made by a US company you might call them up and ask them if a rebuild
kit is available.

I was afraid that had happened to me on my ironworker. But then I tore
it apart and cleaned the tank meticulously and refilled it with new fluid
and now it's much quieter.

Educated Guess: Check that the hydraulic system output relief valve
is opening, and that it's set right. (Do you have a pressure gauge
on the pump output, or on the press cylinder ram?)

If the pump is churning away at it's max pressure whenever idle,
that would cause excess noise from cavitation - the relief valve would
allow some fluid to circulate back to the tank under control. I'd
turn the pressure down a notch and see what happens...

If that works, might even try a second relief valve set far lower
with a ball or solenoid valve in front of it, for the majority of the
time when you don't need the press' maximum output tonnage.

(If I build a powered press, it'll probably use an Enerpac style
air-over-hydraulic pump, they're stone quiet when not in use, and they
creep nicely when throttled back... I have one with an old 3M MS2
cable splicing head attached, all I need is a high-pressure hydraulic
coupler to allow it's use elsewhere.)

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

"Tom" wrote in message "Lloyd E. Sponenburgh" wrote:

Hi,
I'm a farm owner. I recently built a 20-ton hydraulic
press for pushing
bushings and bearings, and for straightening bent
shafting. It works
fine -- two-hand operation, a motor spool control so I
can "nudge" work, and
a two-stage pump to give good ram speed with a high end
pressure.

But the NOISE! It darned near drives me out of the
shop!

I've bunkered the pump/tank affair with concrete blocks
and earth, and with
a 2" thick drywall cover. That vastly reduced the noise
coming directly
from the pump.
But the high pressure line (about 8' long), and even the
press frame itself,
just "rings" LOUD at the gearotor's frequency.

I guess I'm sensitive to that sound. But if I spend a
couple of hours
re-bushing an entire machine, I'm worn out from the
sound.

I don't like wearing earplugs or muffs... they prevent
me from hearing other
important sounds in my work environment; so I'd like to
eliminate the noise
source.

My background is electronics, not hydraulics. I
envision something like a
"low pass filter" (r/c network) eliminating the
"ripple".

Would I be correct in assuming that an air accumulator
near the pump would
eliminate this racket? Maybe that, and an oriface or
flow control valve
either upwind or downwind of the accumulator? I don't
want to spend the
money if it won't help.

If that's not the solution, or if there's more to it
than that, I'd sure
appreciate some help.

LLoyd

If you have the noise problem with the valve in neutral,
you
have either a port plumbing issue or a spool problem, the
hp line vibrating like that, suggests a back pressure
problem.
Try running with the hp hose returning into the tank.

Tom

Do you know if you have/need an open center control valve?
Sounds to me like you have a closed center valve and the
pump is relieving itself at max pressure all the time.
Phil

"Phil Kangas" wrote in message
...
If you have the noise problem with the valve in neutral,
you
have either a port plumbing issue or a spool problem, the
hp line vibrating like that, suggests a back pressure
problem.
Try running with the hp hose returning into the tank.

Tom

Do you know if you have/need an open center control valve?
Sounds to me like you have a closed center valve and the
pump is relieving itself at max pressure all the time.
Phil

I have an open center bypass (safety) valve and an open center control
valve.
When the valves are centered, the pump circulates to the tank at essentially
zero pressure.

My pressure gauge is on the HP line, on the pump side of the control
valve -- so I can see the pressure the pump is delivering, rather than the
working pressure at the cylinder.

The system makes a "screech" when the relief valve opens under full
pressure. That I expect, and don't have a problem with the intermittent
noise. The noise I'm fussing over is continuous while the pump is running
at zero pressure -- just recirculating.

The pump doesn't appear to be cavitating. I've installed a much larger
return filter than necessary, and the intake screen to the pump is clean.
I'm running a low-vis oil comparable to the newer Ford tractor gearcase/lift
oils (about 5W-20 equivalent). Those oils run quieter than the older
straight-30 I used to use. Also, FWIW, the pump is NOT submerged in oil,
but a free-in-air design mounted on a motor-mount plate.

However, as in my original post... it's not the direct noise from the pump
and motor. I've suppressed that with earthworks and drywall. It's the
"ringing" of the HP line and press frame I'm trying to eliminate.

LLoyd

"Lloyd E. Sponenburgh" wrote:

Hi,
I'm a farm owner. I recently built a 20-ton hydraulic press for pushing
bushings and bearings, and for straightening bent shafting. It works
fine -- two-hand operation, a motor spool control so I can "nudge" work, and
a two-stage pump to give good ram speed with a high end pressure.

But the NOISE! It darned near drives me out of the shop!

I've bunkered the pump/tank affair with concrete blocks and earth, and with
a 2" thick drywall cover. That vastly reduced the noise coming directly
from the pump.
But the high pressure line (about 8' long), and even the press frame itself,
just "rings" LOUD at the gearotor's frequency.

I guess I'm sensitive to that sound. But if I spend a couple of hours
re-bushing an entire machine, I'm worn out from the sound.

I don't like wearing earplugs or muffs... they prevent me from hearing other
important sounds in my work environment; so I'd like to eliminate the noise
source.

My background is electronics, not hydraulics. I envision something like a
"low pass filter" (r/c network) eliminating the "ripple".

Would I be correct in assuming that an air accumulator near the pump would
eliminate this racket? Maybe that, and an oriface or flow control valve
either upwind or downwind of the accumulator? I don't want to spend the
money if it won't help.

If that's not the solution, or if there's more to it than that, I'd sure
appreciate some help.

LLoyd

If you have the noise problem with the valve in neutral, you
have either a port plumbing issue or a spool problem, the
hp line vibrating like that, suggests a back pressure problem.
Try running with the hp hose returning into the tank.

Tom

"Lloyd E. Sponenburgh" wrote in message
. net...

My pressure gauge is on the HP line, on the pump side of the control
valve -- so I can see the pressure the pump is delivering, rather than the
working pressure at the cylinder.

The system makes a "screech" when the relief valve opens under full
pressure. That I expect, and don't have a problem with the intermittent
noise. The noise I'm fussing over is continuous while the pump is running
at zero pressure -- just recirculating.

The pump doesn't appear to be cavitating. I've installed a much larger
return filter than necessary, and the intake screen to the pump is clean.
I'm running a low-vis oil comparable to the newer Ford tractor
gearcase/lift
oils (about 5W-20 equivalent). Those oils run quieter than the older
straight-30 I used to use. Also, FWIW, the pump is NOT submerged in oil,
but a free-in-air design mounted on a motor-mount plate.

However, as in my original post... it's not the direct noise from the pump
and motor. I've suppressed that with earthworks and drywall. It's the
"ringing" of the HP line and press frame I'm trying to eliminate.

LLoyd




Try put an acumulator(sp?) on the hp line. That should dampen out the
pressure pulses a bit.
Pat

On Fri, 07 Jan 2005 13:19:36 GMT, "Lloyd E. Sponenburgh"
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

From my (limited) experience, ........

most of my machinery makes so much noise anyway, a little hydraulic
whine is nothing! G

.......you have covered the most obvious reasons for cavitation with
good flow. If the pump is not submerged, you may be getting cavitation
because it's sucking a bit of air. IMLE, this may get _worse_ with low
pressure, higher flow in open centre. Is there any sign of bubbling in
the reserve tank? It may also be simply because the pump has to suck
to a height and is starved. Is there any sort of non-return valve on
the outlet of the tank, before the pump, that may be causing a
restriction?

I have an open center bypass (safety) valve and an open center control
valve.
When the valves are centered, the pump circulates to the tank at essentially
zero pressure.

My pressure gauge is on the HP line, on the pump side of the control
valve -- so I can see the pressure the pump is delivering, rather than the
working pressure at the cylinder.

The system makes a "screech" when the relief valve opens under full
pressure. That I expect, and don't have a problem with the intermittent
noise. The noise I'm fussing over is continuous while the pump is running
at zero pressure -- just recirculating.

The pump doesn't appear to be cavitating. I've installed a much larger
return filter than necessary, and the intake screen to the pump is clean.
I'm running a low-vis oil comparable to the newer Ford tractor gearcase/lift
oils (about 5W-20 equivalent). Those oils run quieter than the older
straight-30 I used to use. Also, FWIW, the pump is NOT submerged in oil,
but a free-in-air design mounted on a motor-mount plate.

However, as in my original post... it's not the direct noise from the pump
and motor. I've suppressed that with earthworks and drywall. It's the
"ringing" of the HP line and press frame I'm trying to eliminate.

LLoyd

On Fri, 07 Jan 2005 13:19:36 GMT, "Lloyd E. Sponenburgh"
wrote:

snip

However, as in my original post... it's not the direct noise from the pump
and motor. I've suppressed that with earthworks and drywall. It's the
"ringing" of the HP line and press frame I'm trying to eliminate.

LLoyd



Can you substitute flexible hydraulic hose for the (presumably) rigid metallic
pipe?


Mark Rand
RTFM

"Tom" wrote in message
...

Perhaps you could supply the make & type of pump and describe the
the the way in which it is plumbed to the tank? What height does
the pump have to draw the oil from the tank?

Also, how do you know that "the pump circulates to the tank at
essentially zero pressure."?

Tom

It's a cheap Prince 11gpm two-stage pump. Cheap. Hooked up to a 1725RPM
2HP pool pump motor. Lovejoy coupling.

The pump is _below_ the fluid level in the reservior. Actually, about 8"
below.

I have a pressure gauge on the HP line, just before the ONLY restrictions in
the bypass circuit -- namely, the OC bypass valve itself.

The return lines are larger than the HP line. The HP line is 1/2", 3-wire,
neoprene coated standard stuff from NAPA.

LLoyd

On Sat, 08 Jan 2005 16:48:52 -0800, Tom vaguely
proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

"Lloyd E. Sponenburgh" wrote:

"Tom" wrote in message
...

Perhaps you could supply the make & type of pump and describe the
the the way in which it is plumbed to the tank? What height does
the pump have to draw the oil from the tank?

Also, how do you know that "the pump circulates to the tank at
essentially zero pressure."?

It's a cheap Prince 11gpm two-stage pump. Cheap. Hooked up to a 1725RPM
2HP pool pump motor. Lovejoy coupling.

The pump is _below_ the fluid level in the reservior. Actually, about 8"
below.

I have a pressure gauge on the HP line, just before the ONLY restrictions in
the bypass circuit -- namely, the OC bypass valve itself.

The return lines are larger than the HP line. The HP line is 1/2", 3-wire,
neoprene coated standard stuff from NAPA.

LLoyd

For someone asking for help, one gets the impression that you're
not amenable to suggestion.

PMFJI. Ease up. He is attending to your questions.

Either start from basics or forget it.

"Lloyd E. Sponenburgh" wrote:

"Phil Kangas" wrote in message
...
If you have the noise problem with the valve in neutral,
you
have either a port plumbing issue or a spool problem, the
hp line vibrating like that, suggests a back pressure
problem.
Try running with the hp hose returning into the tank.

Tom

Do you know if you have/need an open center control valve?
Sounds to me like you have a closed center valve and the
pump is relieving itself at max pressure all the time.
Phil

I have an open center bypass (safety) valve and an open center control
valve.
When the valves are centered, the pump circulates to the tank at essentially
zero pressure.

My pressure gauge is on the HP line, on the pump side of the control
valve -- so I can see the pressure the pump is delivering, rather than the
working pressure at the cylinder.

The system makes a "screech" when the relief valve opens under full
pressure. That I expect, and don't have a problem with the intermittent
noise. The noise I'm fussing over is continuous while the pump is running
at zero pressure -- just recirculating.

The pump doesn't appear to be cavitating. I've installed a much larger
return filter than necessary, and the intake screen to the pump is clean.
I'm running a low-vis oil comparable to the newer Ford tractor gearcase/lift
oils (about 5W-20 equivalent). Those oils run quieter than the older
straight-30 I used to use. Also, FWIW, the pump is NOT submerged in oil,
but a free-in-air design mounted on a motor-mount plate.

However, as in my original post... it's not the direct noise from the pump
and motor. I've suppressed that with earthworks and drywall. It's the
"ringing" of the HP line and press frame I'm trying to eliminate.

LLoyd

Perhaps you could supply the make & type of pump and describe the
the the way in which it is plumbed to the tank? What height does
the pump have to draw the oil from the tank?

Also, how do you know that "the pump circulates to the tank at
essentially zero pressure."?

Tom

"Lloyd E. Sponenburgh" wrote:

"Tom" wrote in message
...

Perhaps you could supply the make & type of pump and describe the
the the way in which it is plumbed to the tank? What height does
the pump have to draw the oil from the tank?

Also, how do you know that "the pump circulates to the tank at
essentially zero pressure."?

Tom

It's a cheap Prince 11gpm two-stage pump. Cheap. Hooked up to a 1725RPM
2HP pool pump motor. Lovejoy coupling.

The pump is _below_ the fluid level in the reservior. Actually, about 8"
below.

I have a pressure gauge on the HP line, just before the ONLY restrictions in
the bypass circuit -- namely, the OC bypass valve itself.

The return lines are larger than the HP line. The HP line is 1/2", 3-wire,
neoprene coated standard stuff from NAPA.

LLoyd

For someone asking for help, one gets the impression that you're
not amenable to suggestion. Either start from basics or forget it.
If you have a noise problem, the only way is to eliminate potential
causes. That you appear to have an excessively noisy pump can only
be confirmed if you remove any valves and run it straight into the
tank. Noise can be caused by elbows too close to the intake side
of the pump and causing cavitation.
Your problem also can be the result of a poorly assembled hose.
Assume nothing.
I looked at a press a couple of years ago that exhibited just about
identical symtoms to yours. Found that the valve, purportedly, an
open center unit, was set up as a closed center and required the
removal of a blanking plug to act per description. The result was
a noise level about 1/10 of previous.

Tom

Old Nick wrote:

On Sat, 08 Jan 2005 16:48:52 -0800, Tom vaguely
proposed a theory
......and in reply I say!:

remove ns from my header address to reply via email

"Lloyd E. Sponenburgh" wrote:

"Tom" wrote in message
...

Perhaps you could supply the make & type of pump and describe the
the the way in which it is plumbed to the tank? What height does
the pump have to draw the oil from the tank?

Also, how do you know that "the pump circulates to the tank at
essentially zero pressure."?

It's a cheap Prince 11gpm two-stage pump. Cheap. Hooked up to a 1725RPM
2HP pool pump motor. Lovejoy coupling.

The pump is _below_ the fluid level in the reservior. Actually, about 8"
below.

I have a pressure gauge on the HP line, just before the ONLY restrictions in
the bypass circuit -- namely, the OC bypass valve itself.

The return lines are larger than the HP line. The HP line is 1/2", 3-wire,
neoprene coated standard stuff from NAPA.

LLoyd

For someone asking for help, one gets the impression that you're
not amenable to suggestion.

PMFJI. Ease up. He is attending to your questions.

Either start from basics or forget it.

WPYC?