Thread: Hydraulic Pump

A hydraulic pump lifts 200 kg weighted body to 25 meter height with in 10 seconds.The cylinder has 0.15 m radius.What is the power,discharge and other specification needed for the pump ?

Originally Posted by rahulmohan

A hydraulic pump lifts 200 kg weighted body to 25 meter height with in 10 seconds.The cylinder has 0.15 m radius.What is the power,discharge and other specification needed for the pump ?

You have weight, distance and speed, so you can figure out power. (1 HP is 550 foot-pounds per second.)

You know radius and you know height so you know volume of liquid required per second.

You know weight and area so you know pressure required.

Is it possible to lift 200 kg in 10 seconds upto 25m using a hydraulic pump ?

If possible then which pump should be used.I mean its whole specification.Please help.

Originally Posted by rahulmohan

Is it possible to lift 200 kg in 10 seconds upto 25m using a hydraulic pump ?

If possible then which pump should be used.I mean its whole specification.Please help.

You don't mean a pump, you mean a hydraulic motor. A pump moves a fluid, using mechanical power input, whereas you want a flow - or fall - of liquid to generate a mechanical power output. The opposite.

If you lift 200kg through 25m in 10 secs, this is obviously equivalent to lifting 20kg through 25m every second, or 500kg through 1m every second.

1kg weighs ~10N, so moving it 1m against this force requires 10J of work. So if something lifts 500kg 1m each second, it does work at the rate of 5kJ/sec, i.e. has a power requirement of 5kW.

If you have a loss-less hydrostatic motor (improbable), then obviously an equivalent fall in water will lift this mass, i.e. water falling a rate of 500kg-m/sec will do it, i.e. half a tonne/sec falling through 1m or 50kg/sec falling through 10m, and so on.

If you have some other sort of motor, then you need to consult the manufacturer as to what flow rate and/or head of water you will need to get a power output from the motor of 5kW.

If this is homework, that's all I'm giving you. If it's a reciprocating motor, you can work out, from cylinder and crank dimensions and speed of operation, how big and/or fast this motor has to be to achieve the required power.

Thanks for your reply but i want to know is it possible do so.And which hydro motor i should consider.I heard that hydraulic power can be used to lift huge weights but its a time consuming process.so lifting it in 10 seconds sounds impossible.Well i don't know. Is it possible ?

Originally Posted by rahulmohan

Thanks for your reply but i want to know is it possible do so.And which hydro motor i should consider.I heard that hydraulic power can be used to lift huge weights but its a time consuming process.so lifting it in 10 seconds sounds impossible.Well i don't know. Is it possible ?

Well clearly you're not someone trying to cheat with his school homework - we get a few of those so I apologise for suspecting you!

What you ask is a bit beyond my experience but I don't see why not in principle. I suspect, though, that most commercial hydraulic motors will be designed to be powered by a supply of highly pressurised hydraulic fluid, rather than water, i.e. as part of a hydraulic power transmission circuit comprising an engine-driven pump, a series of high pressure lines and hoses and one or more hydraulic motors at the other end. I do know from my time in the lubricants industry that such setups are quite common.

From your question I can't tell whether this is what you are looking for, or whether you want a water-powered motor to do what you ask, using a head of water from a dam or commercial water supply. Whether you will easily find a motor designed to be driven by a large volume of comparatively low pressure water I do not know. You may have some luck with small scale hydroelectric impellers, which are designed to use a head of a few tens of metres of water. But perhaps there are more knowledgeable readers on this forum who can help here.

Originally Posted by rahulmohan

Thanks for your reply but i want to know is it possible do so.And which hydro motor i should consider.I heard that hydraulic power can be used to lift huge weights but its a time consuming process.so lifting it in 10 seconds sounds impossible.Well i don't know. Is it possible ?

200 kilograms is not very much compared to an automobile. When you take your car in for service, they will put it on a hydraulic jack and lift it up a couple of meters in a few seconds, so I'm pretty sure it wouldn't be very hard to do what you want.

Originally Posted by rahulmohan

Thanks for your reply but i want to know is it possible do so.And which hydro motor i should consider.I heard that hydraulic power can be used to lift huge weights but its a time consuming process.so lifting it in 10 seconds sounds impossible.Well i don't know. Is it possible ?

Do the math. A 1HP* pump can lift 550 pounds 1 foot in 1 second. Getting other speeds/weights is simple division.

(100% efficient, frictionless etc)

Thanks for your informations.Now i got some idea about this.