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How Can I Amplify My Hydraulic Pressure?

01/24/2012 2:54 PM

I have a Hydraulic pump that is good for 1500PSI or just over 100bar, is there a simple way to amplify this to nearly 6000Psi or 413bar?

I did think about feeding it into a hydraulic cylinder with a large piston surface area, then pressure on the upper side of the cylinder is fed to another Cylinder at a Higher pressure to gain a greater thrust using a small pump. If you understand what i am trying to explain.

The theory seems to make sense to me , but probably doesn't work in practice.

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#1

Re: How Can I Amplify My Hydraulic Pressure?

01/24/2012 3:15 PM

Not enough information. 1500PSI is only half of the equation. What's the flow rate?

The cylinder thing might work, if you can get it small enough.

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#2

Re: How Can I Amplify My Hydraulic Pressure?

01/24/2012 3:35 PM

Before you go down that approach... you should check to see if the down stream equipment and hoses can handle the higher pressure.

It may be more cost effective and somewhat safer just to buy a high pressure equipment set or equipment rated to perform the tasks you want to achieve.

Higher pressures in your existing equipment will probably cause it to fail, between the obvious risk of the falling load, the pressure release at the point of failure has a high chance of causing injury due to the "Explosive" force of the rupture.

Be Safe,

Regards,
Sapper

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#19
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Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 8:30 AM

Safety is not a major concern like it would be in a pneumatic system. The oil is incompressible and does not store any energy. You want to design the system to store as little energy as possible so when something fails, it is not a dangerous event. We hydraulically test to 3000 psi routinely. When a part fails it simply spits out a small volume of fluid.

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#26
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Re: How Can I Amplify My Hydraulic Pressure?

01/26/2012 3:50 PM

Welderman,

While I agree that there is a vast difference between the failure of a pneumatic system or hydraulic system, that spurt at the pressures we are talk about are entirely capable of removing skin & muscle, a burst fitting can still crack a skull or break a bone.

The upside is that due the the incompressibility of a liquid, the time for damage to occour is much less as the liquid itself does not store the energy well, the lines however will have stretched slightly under pressure and will impart a small amount of stored energy.

Having said that, Safety is always a Major concern.

Regards,
Sapper

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#3

Re: How Can I Amplify My Hydraulic Pressure?

01/24/2012 4:18 PM

Are you thinking about a master cylinder, like in a car's braking system?

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#4

Re: How Can I Amplify My Hydraulic Pressure?

01/24/2012 4:46 PM

This is not actually a piece of equipment that is built. I have the pump and the flow is irrelevant at the moment. I was just thinking about how to amplify the pressure. I build hydraulic hose assemblies as a business and am thinking of experimenting with this.

So yes i am well aware of the implications of hose failure etc.

And finally yes, i guess you could say it is along the same prinicples of a Brake master cylinder in theory.

All i want to get is other people ideas to see what they think as i have yet to find a commercially available system that does just this. And by using parts off my shelf to see if it is possible.

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#13
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Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 1:43 AM

It depends upon the body of the pump, if modified whether it can sustain such pressure. To increase pressure, lower the dia of plunger and of course the cylinder with pushing reduced dia sleaves. Then you would have to change valves inside of pump. Increase the horse power running the pump. Mind you 6000 psi is pressure when leaked facing human being may cut the skin. Therefore; this experiment you do in a hole dug in the ground for this purpose with all that safety pre-cautions.

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#15
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Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 2:00 AM

Dig a hole???? Come on man... There are other ways to properly and safely test a system, if you need to rent a backhoe to test your theroy then mabie you shouldnt have built it to start with LOL

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#24
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Re: How Can I Amplify My Hydraulic Pressure?

01/26/2012 12:41 AM

If you dont want to hire back hoe, ok buy steel sheets, make a box with engress - egress provision. Which would be cheaper, select but cannot bypass safety precaution.

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#5

Re: How Can I Amplify My Hydraulic Pressure?

01/24/2012 5:39 PM

Seems to me you need a smaller volume pump or a higher powered motor....or possibly more revolutions per stroke...

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#6
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Re: How Can I Amplify My Hydraulic Pressure?

01/24/2012 5:52 PM

Pump is 0.9cc per rev, 12v motor is 1.5hp/ 1KW

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#8
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Re: How Can I Amplify My Hydraulic Pressure?

01/24/2012 7:00 PM

I would try gearing the motor down maybe 6 to 1 to the pump...if possible....

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#7

Re: How Can I Amplify My Hydraulic Pressure?

01/24/2012 6:19 PM

Google "pressure intensifier"

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#17
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Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 4:51 AM

GA too Dave. The wheel has been invented......

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#9

Re: How Can I Amplify My Hydraulic Pressure?

01/24/2012 7:44 PM

Sounds logical in thoery. Pressure is just force over surface area, so the mechanical force generated by one cylinder transferred to a second cylinder of lesser surface area will give increased pressures from the second cylinder.

The pressure increase will be the (inverse) ratio of the relative surface areas of the two cylinders.

GA to Sapper for safety. Make sure all the equipment, cylinders, hoses, connections, mechanical linkages, are designed for the increased forces and pressures involved.

But sounds like your aware of the risks involved, so go ahead and build it.

Good luck,

Anthony

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#10

Re: How Can I Amplify My Hydraulic Pressure?

01/24/2012 11:14 PM

As per lyn's reply, it is very important you state the intended flow rate as many options are available to reach your pressure. One option is your cylinder, there are many others as well.

Look at a typical Koomey BOP system for offshore applications for instance. Typically we use test equipment that are capible of much higher pressures (up to 30,000 psi)however systems become more complex with accumilators, low pressure pumps feeding high pressure pumps, etc. This is due to your desired flow rate and application

Can you share a general expected flow and application? Otherwise everything is just theroetical.

It is quite possible your existing pump may be modified, but FIRST be sure your existing equipment is capible of supporting such pressures. The pump itself, connections, etc.

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#11

Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 12:03 AM

Taurus66, your theory is correct and will work as you predict. We just completed a design and build using the same principle. We connected a 4in bore hyd cyl to a 2in bore in a closed circuit. The 2in bore cyl was then coupled to a high ratio acme screw actuator which provides accurate positioning. We were able to control a 20000 lb load within the required .001 accuracy better than a servo hydraulic system. Keep in mind that this setup does not increase pressure. The pressure remains the same in both cylinders it's just that the larger output cylinder will generate more force because of the larger surface area. It will also move slower. The pressure in the lines remains the same.

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#12

Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 12:14 AM

All you need is one cylinder, feed the low pressure to the piston side port and take the high pressure from the rod side port.The ratio of areas will determine the increase in oil pressure. You will need to relieve pressure on the piston side and apply the pressure to the rod side, through a one way check valve, to retract the piston. You can use a standard forward, reverse valve, to pressurize or depressurize the output. You need to ensure all equipment will withstand the higher pressure.

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#14

Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 1:45 AM

taurus 66

check out minibooster.com i think this is what your looking for.

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#16

Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 3:55 AM

What you describing is a pressure intensifier. It is a standard piece of kit in the hydraulics industry, especially water hydraulics used for water jet cutting. Building your own version is not a good idea as standard cylinders are not built to withstand these pressures. Buy from a recognised manufacturer who can guarantee that the whole thing is not going to explode.

If you do decide to build your own, Goodbye, RIP

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#18

Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 7:57 AM

This makes total sense, If you imagine the clutch pedal on a car you have a small cylinder feeding a larger cylinder which increases the pressure, I've seen a demonstration where the chap was using a hypodermic needle to how that by injecting into a large cylinder just a small amount of pressure could lift a large amount of weight, This only works on a closed system & depends on the amount of travel you need, As you are multiplying the pressure X 4 then the amount of travel of the small cylinder has to be sufficient to move the final piston by what ever length you require ie: say the diameter of the first piston is 20mm with a stroke of 100mm the final movement will be the volume of the small cylinder divided by four this is assuming the diameter of the larger cylinders area is X4. ( I cant find the symbol for pie on my keyboard ) Anyway hope this helps.

Bazzer

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#20

Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 8:40 AM

Gentlemen, Thankyou very much for all your input. This is entirely theory at this stage but with some of the advice given i can now look at building my project. The flow is not hugely important to me as speed of operation needs to be slow.

The project will be built with the highest possible pressure in mind. So all parts will be capable of 10000 psi plus working pressure.

Like i say this is a way off down the line.

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#21
In reply to #20

Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 9:23 AM

Yes there are commercial pressure amplifiers.-

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#22

Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 9:57 AM

If its a test, then feed the 1500 PSI into a piston which is loaded on the low side with oil and compress it.

You have to calculate the pressure on the piston to get the proper pressure from the shaft

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#23

Re: How Can I Amplify My Hydraulic Pressure?

01/25/2012 10:40 AM

Use a lever, pinned at one end with the driven piston at one unit of length and the driving piston at four units of length from the pin. The pin must be good for 3/4 of the force in the driven piston.

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#25

Re: How Can I Amplify My Hydraulic Pressure?

01/26/2012 12:02 PM

Very well known Pascal's Principle is applied in any hydraulic intencifier. In market these are easily available in diffrent capacities

Explanation - The figure displays two joined cylindrical chambers. They both have different diameters and including the connecting tube, are filled with liquid. Since the second piston is larger, it produces a larger force than the force applied to the smaller piston:

F2 = F1(A2/A1)

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AbdulWasay (2); ajwinemaker (1); Bazzer Englander (1); DaveR (1); ferquiza (1); Henk klep (1); jhhassociates (1); lyn (1); Mukesh0861 (1); passingtongreen (1); Sapper (2); SolarEagle (2); taurus66 (3); TerraMan (1); Tim in Mexico (2); Usbport (1); vargaalex (1); vtbgiraud (1); Wal (1); welderman (1)

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