Hydraulic Calculations?

Is this work, or homework?

What drives the hydraulic motor that drives the pump?

What makes you think the pump will be exposed to hydraulic fliud? Wouldn't it be driven by a shaft from the motor to the pump?

With no cylinders, the volume of working fluid will remain constant, except for thermal heating.

Fess up. What are you really trying to do?

Well it's kind of both. I decided to go make a let's say essay about a topic i don't know much about but will help me in the future on my job i do...... I know how to do schematics, but never done any calculations and that's what i'm trying to learn at moment. The problem is the books i have don't give me much info about it, so that's why i asked about some recomendations for books.

The system is very simple. The engine of a vehicle or separate fuel engine drives a hydraulic pump with constant speed. The pump spreads the hydraulic oil further in the system towards the hydraulic motor that drives the centrifugal fire pump. Between the pump and the motor there is a valve that's used for regulating the speed of the motor (the centrifugal fire pump requires change of speed due to more than one consumer which effect the flow of the firefighting system).

So i ran onto some trouble like i said in the previous post.

1. I tried to determine which filter should be used, the idea was a suction filter since the pump and the motor both require the same filtration.... but then i read that the suction filter should be above >100 micrometers, and that's much more than i need, so that's no option.

2. Can't find any formula for determining how big the oil tank should be. The only formula i found isn't useful for me.

For fundamental hydraulics I would recommend the Fluid Power Design Handbook, published by B&T Hydraulics & Pneumatics, ISBN 0-9653599-0-5. You can find it on line with a used book search. It doesn't cover the myriad of circuits and functions but it is a good guide to start with. There are plenty of other good publications but they will get quite in depth.

For now, do a search for formulas related to the power, speed, torque and flow of hydraulic pumps and motors. Things get a bit trickier when one has to consider often unknown efficiencies, but it doesn't sound like you'll be getting into that yet.

Generally, you will have a large (keep the back pressure to a minimum) return filter for coarse filtration, a suction strainer (rock catcher) to the pump and a 3 to 10 micron pressure filter. If the reservoir and system are properly flushed and cleaned prior to commissioning, you will have pretty much eliminated the chance of getting anything into the pump in the future.

Rough rule of thumb, the reservoir will be one gallon per HP.

Don't forget the cooler. The cooler has to be rated (at a minimum) to remove the heat of inefficiency; e.g., 10 HP system, 80% efficient = 2 HP cooling required.

At the bottom of this past post, I link a reference to some excellent books that will be of tremendious assistance to you.

JavaHead

A couple other sources for information:

Lightning Reference Handbook. It is usually published by individual hydraulic equipment suppliers. I see by my two versions:

- Eighth Edition: Berendsen Fluid Power, Inc., Tulsa, OK

- Sixth Edition: Paul-Munroe Hydraulics, Inc., Whittier, CA

Vickers Industrial Hydraulics Manual, ISBN 0-9634162-0-0

Hi again.

Sorry I didn't comment anything. Got my hands on some books in the meantime so have been studying those.....

Am still struggling with some things here though....

The pump i have to use on my system has a flow over 500 l/min. Since the system is a part of a vehicle, the info i keep digging out that the oil reservoir volume must be

2-4 * pump flow is just not possible. Am i missing something here!? A 1500 l tank!?