Synchronise Rams

Synchronise Rams
Over the years I have seen many methods used to synchronise hydraulic rams, some successful and some bordering on the bazaar.
Getting rams to move together can be tricky and applications like “ A frame” cranes can be potentially dangerous if the wrong method is used.
The simplest method is to join rams together using a mechanical strut / beam that is strong enough to take any out of balance forces. We often see rams used this way on Skip Lorries where the two rams are joined together with a cross beam and the input flow split using just equal lengths of pipe work.
More accurate control can be effective with flow divider valves, gear and piston motor types. These offer more better control with accuracy between 5-10% of stroke but as wear increases these figures will also increase.
The most accurate form of synchronisation will be achieved using a servo closed loop control with linear transducer feedback. One cylinder will be driven whilst the other slaved.
I have also used NC valves with stepper motor control. Using one digital input signal to two stepper motors that drive the NC valves. This has its own inbuilt mechanical feedback mechanism that can synchronise rams to just a few microns even with an off centre load.

Should you paint inside the tank

Should the inside of the tank/reservoir be painted or left bare?
This is a question I am often asked.
Leaving the tank bare risks the build up of rust and this can drop off and contaminate the oil.
Painting the tank with a good epoxy has benifits including.
1) It will seal in particles missed from cleaning (bits of weld splatter)
2) Prevents rust building up.
The issue I have with painting is if comes off (big problem!)
I have seen tanks where the lids and the sides have been painted only down to the oil line.

Holding a Load

A problem that raises its head every so often is holding a load on a ram.
I don’t mean for a few minutes or even an hour I am talking about many hours or even days.
Holding a load for a short time can easily be done using a pilot operated check valve. This is probably the best valve because being a seated poppet they are less likely to leak although a little contamination under the seat can cause a problem.
On occasions I have been asked to close the ram off with ball valve, which I refuse to do.
Any leak across the piston can cause pressure intensification due to the ratio of the piston and rod area.
As far as I know there is no way of holding a load on a ram for long periods of time and it should be no surprise to raise a load one day only to see it down the next unless a mechanical locking mechanism is used.
I would like your views, maybe someone out there has other interesting ideas they can share.
Cheers
Bob

I was kindly sent this by Sampathkumar Iyengar showing a filter screen in a hydraulic tank. I have never seen this done before. Looks a very good idea!
Many thanks Sampathkumar

Dear Bob,
These screens serve the purpose of filtration of oil from the dirty side to the clean side of the reservoir.
These screens can be periodically removed for cleaning and re inserted in the slots.
These screens have advantage of large area of wire mesh available to trap dirt and debris from the return line of systems
For the suppression of bubbles we weld a sheet with a 45 degree slope with perforations on the side leading to the clean chamber
I am enclosing an additional photos with remarks for clarity.

Trust the information assists


Best regards


Sampathkumar Iyengar

ITV Made In Britain

Are we now beginning to wake up from a long sleep?
I screamed with delight as I watched the ITV Panorama program.
For most of my life I have watched my highly skilled friends and some great manufacturing and Engineering companies relegated to the scrap heap. We are beginning to talk about the importance of Manufacturing as a means to reduce our huge deficit. Is this the end of the beginning?
The only negative: Digby Jones (a man I respect for supporting manufacturing) said that it did not matter who owned British Companies as long as they are here.
But that is the whole point, they don't always remain here! Cadbury and Kraft come to mind.
We need more British manufacturing created by our own talented people.
Laws should be made to prevent takeovers that are not in Britain's interest and where it has a negative impact on our communities. We must also acknowledge engineering talent the same way as we do for financial services. Engineering, Manufacturing and Technology must become COOL again!

She loves me she loves me not!

Sheffield Forge Masters were promised an £8Million loan to invest in their business.
This would have secured their position as a major UK manufacture in their specialised field and prevent even more manufacturing jobs leaving our shores.
This loan offer has now been withdrawn and no doubt will have put the companies future in question.
For Gods sake what on earth are we doing!
Are we trying to finish off the last remaining remnants of a once great industrial country or send that old familiar signal out to our manufacturers that we still love our relationship with the financial markets in preference to manufacturing.
Well i think this government needs to make its mind up what they want us to do because we cannot keep on going with these mixed messages.
We have given, yes given millions of pounds bailing out banks that have behaved like Bookmakers. Gambling our money with fatal consequence. We are all now paying the price for this addiction. We now need to look at the plain truth, that money and wealth must be worked for and there is no such thing as a free ride.
A Farmer buys seed sows his crop and harvests his hard work. He now has a crop that has more value than the seed that he sells to make a profit. All manufacturers do the same. Its harder than moving money from one place to another and making a fortune but it is honest, sound and safe. Ask the Germans and the Chinese they have been doing it for years and thriving.
This Government must wake up, smell the coffee and invest (not give) in Manufacturing before we loose everything.