anyone have experience using hydraulics for speed reduction ?

[knighty]

it's a giant washing machine, spins 1 ton of tripe in 1000 litres of water

hydraulic motor ratings... the ebay one linked above says it's 35kw cont. max speed 650rpm

does that mean it's 35kw at 650rpm... so at 40rpm it'll be a lot lower ?


even if the pressure stays the same, the flow rate changes, so the pumped power must change ?
(I don't think 'pumped power' is right but I don't know the right terminology)

 

[dannyp]

if that's 155cc/rev

then I need a hydraulic pump delivering 6200cc/min (6.2litres/min) to drive it at 40 rpm yeah ?


I'm leaning towards chains, I thought they were really stretching... I know what I'm doing with chains, I can keep a full set of spares on the shelf and if something breaks I can fix it quick

yep 6.2 ltrs minute on a 3000 rpm motor thats only 2cc your way off on displacements and pressure's at that tho, buy the sounds off it you'll be upto inpractical pressures. less pressure and more flow means it lasts longer.

i don't exactly know what your application is but at a bind guess id start with somethign like this for the oil

https://www.ebay.co.uk/itm/HYDRAULI...984716?hash=item1c9e0187cc:g:NOEAAOSwA~VaHxTe

 

[dannyp]

it's a giant washing machine, spins 1 ton of tripe in 1000 litres of water

hydraulic motor ratings... the ebay one linked above says it's 35kw cont. max speed 650rpm

does that mean it's 35kw at 650rpm... so at 40rpm it'll be a lot lower ?


even if the pressure stays the same, the flow rate changes, so the pumped power must change ?
(I don't think 'pumped power' is right but I don't know the right terminology)

yep lots lower ( 35kw / 650 rpm ) * 40 will give an ish factor about 2.1 kw that wont be quite right but close enough to know it's not much use imo, generaly with hydralic motors more pressure = more torque, so while it may be capable of putting oy 35 kw at 650 rpm , it's not going to be abel to make much more torque at 40 rpm. im trying to gadgue how much torque your application needs, any idea how much power the current motor actualy draws

 

[knighty]

740rmp motor would mean 6.2litres/min is 8.3cc... but sky high pressure ?

I'll email a couple of hydraulic places for quotes, get the pump/motor from the same place, matched to start with

I might be able to get a discount, he's retired now but my uncle used to own a pirtek depo
(I'd have asked him about this but have been working crazy hours so don;t see him much)


whatever happens.. I'd need a motor with a really high flow rate, so the flow/pressure at the pump would be reasonable ?

my brother mentioned JCB motors for driving wheels/tracks, they might be a good place to look :-)

 

[dannyp]

yes, build quite a bit of appel kit at work and we notice the pump life drop off when pressures are getting high, we often test stuff useing a tractor, put pressure /flow meter in line and just turn the flow up/down on the tractor till the machene works right then we know how meany lpm are required and the pressure therefore the KW.

id go for a wheel motor off a self propeled crop sprayer or alike ( you chuld bolt a 1 ton drum to that and it wouldnt care ) if you desire varible speed is sugest a varible displacement squashplate pump, ( you then basicly have a hydrostaic transmition ) push leaver forwards it goes faster upto maximum pump displacement.

but say if you had a 60 ltr per minute pump , thats a 20cc displacement pump running at 3000 rpm ( its usual just to direct drive off a 2 pole motor ) if you were running @ 1500 psi thats roughly 14 HP being transmitted

now say you have a 20 hp or a 25 hp motor on it that just means the pressure can go higher, to get things moveing thats ideal but things arnt stressing when its running, and you can keep the relief valve pressures sensibly away from the working pressures, say spec it to run at 1500-1700 psi, relief valves blow off at say 2400 - 2500. it should run happily even an ali cased group 2 pump will do 2900 psi ( iron / steel will go higher ) but as said coninous run you want to be lower than that

 

[8ob]

it's a giant washing machine, spins 1 ton of tripe in 1000 litres of water

hydraulic motor ratings... the ebay one linked above says it's 35kw cont. max speed 650rpm

does that mean it's 35kw at 650rpm... so at 40rpm it'll be a lot lower ?


even if the pressure stays the same, the flow rate changes, so the pumped power must change ?
(I don't think 'pumped power' is right but I don't know the right terminology)

On piston motors torque is produced by pressure not flow, 2000psi @ 20 ltrs a minute acting on the top of a piston will produce the same torque as 2000psi @ 40ltrs a minute but will be half the shaft speed. Personally I would keep away from machine tracking motors, they have gear reduction sets in them which is just another load of potential maintenance/future grief which in this instance is unnecessary. Keep flow rates down to just the minimum requirement, less heat which in turn wont cane the fluid. Throttled down hydraulics are inefficient heat makers.

Bob

 

[Luke]

Edit - already answered. Should have read to the end of the thread.

 

[Rannsachair]

I have worked on quite a few trommel applications in the past ( I was applications engineering manager with Bosch Rexroth 15 years ago) which appear a similar application, we supplied radial piston motors: https://www.boschrexroth.com/en/xc/...mobile-hydraulics/motors/radial-piston-motors our main competitor supplied similar https://www.poclain-hydraulics.com/en/products/motors either could be used. Staffa kit is good though seem to recall was pricey.

 

[slim_boy_fat]

@knighty Thinking outside the box

Buy this under 'make an offer' to include the 'spares' [mobile phone number at the foot of the ad ] machine the Seller has, rob the [better] control block from one or the other along with a/the hydraulic drive motor, make one good from the two, stick them both back on the 'Bay at a silly low starting price [or "B-i-N"].

https://www.ebay.co.uk/itm/TORO-GRE...398484?hash=item23c904ec94:g:RfcAAOSwzAVdgzjK

 

[Brad93]

Is it a trommel you want to build?

Edit: Just seen it’s a tripe washer.

 

[8ob]

@knighty Thinking outside the box

Buy this under 'make an offer' to include the 'spares' [mobile phone number at the foot of the ad ] machine the Seller has, rob the [better] control block from one or the other along with a/the hydraulic drive motor, make one good from the two, stick them both back on the 'Bay at a silly low starting price [or "B-i-N"].

https://www.ebay.co.uk/itm/TORO-GRE...398484?hash=item23c904ec94:g:RfcAAOSwzAVdgzjK

There are two of those festering in the yard

 

[4String.]

it's a giant washing machine, spins 1 ton of tripe in 1000 litres of water

I can picture lots of non-working class southern readers wondering what tripe is .

 

[slim_boy_fat]

There are two of those festering in the yard

I spent many hours sitting on those, often in the rain . Did you know that it's possible to 'slide'' them on those 'slicks' on wet grass?

 

[8ob]

I can picture lots of non-working class southern readers wondering what tripe is .

The difference is Mr @4String. is the southerners only feed it to their dogs

 

[WorkshopChris]

A year-old post resurrected by someone posting a link to a company.

 

[octo0072000]

I wonder if this ever got finished always like to see a update on stuff like this as it was a year ago with no updates

 

[knighty]

nope... didn't even start it!

the machine washes bible tripes or manifolds (different names for the same thing depending where you're from)

aaaaand... the market changed so they're getting exported to china et. for people to eat, too expensive for dog food now, I've gone from doing 8 loads a day to 1 load a day

for 1 load a day I'll just stick with my old machine, not worth the cost of building another for that

 

[octo0072000]

nope... didn't even start it!

the machine washes bible tripes or manifolds (different names for the same thing depending where you're from)

aaaaand... the market changed so they're getting exported to china et. for people to eat, too expensive for dog food now, I've gone from doing 8 loads a day to 1 load a day

for 1 load a day I'll just stick with my old machine, not worth the cost of building another for that

thanks for the update