How to Design Hydraulic Power Pack?

How to Design Hydraulic Power Pack?

The design process begins by having a specific performance requirement for every component we would wish to include in our system.
Remember, every hydraulic component listed in chapter 3 will directly affect the design process and the cost.
Moreover, the size of say a cylinder, type of valve or type of a motor will determine the unique performance characteristics of the hydraulic power packs.
This explains the reason why we have micro hydraulic power packs, mini hydraulic power packs, etc.
Let me review the hydraulic power pack design components you need to consider.

The standard design features and performance you need to consider include the following:

1.Motor Pumps

You need to specify the rating and capacity of the hydraulic pumps. They will push the hydraulic fluid in the circuit to do work.
Some of the key calculations for the hydraulic pumps include:
Horsepower required to drive the pump
In this case, you’ll use this simple formula: GPM×PSI×.0007
This is a “rule-of –thumb” calculation. For instance, if your pumps should drive 5gpm at 1,500 psi, then you need a drive motor whose horse power is 5.25kw.
Hydraulic pump displacement needed for GPM of Output Flow:
You’ll determine this using the formula: 231×GPM÷RPM
Thus, assuming displacement of 5 GPM at 1500 RPM, then using the equation above, you’ll get 0.77 cubic inches per revolution.
Pump Output Flow (in Gallons Per Minute):
You can obtain this using the formula: RPM×Pump displacement ÷231
Implying, in case you need to determine the amount of oil that your pump will produce with a displacement of 2.5 cubic inch pump operating at 1200 rpm?
Inserting these into the above equation you get: 12.99 GPM.
Basically, these are the four basic equations you need to know when designing choosing the best pump for your hydraulic power pack.

2. Hydraulic Cylinder Calculations

Below are important hydraulic cylinder equations you need to consider in your design process:
Cylinder Rod End Area (in square inches):
You get this using: Blind end area-Rod area
This implies, you need to determine the area of these sections. Of course, you have to determine geometrical figure then use the appropriate formula.
For instance, when you’re dealing with a square you will use: L×L. In the case of a circle, you’ll use: π×radius×radius.
Cylinder Blind End Area (in square inches):
You’ll use the formula: PI×(Cylinder radiu)2
Again here, the formula will depend on the geometrical shape in question.
Cylinder Blind End Output (GPM):
The formula is: Blind end area÷Rod End Ares×GPM In
Cylinder Output Force (in pounds):
Use the formula: Pressure (in PSI)×CylinderArea
Cylinder Speed (in inches per second):
The formula is: (231×GPM)÷(60×Net Cylinder Area)
GPM of Flow Needed for Cylinder Speed:
Use the following formula: Cylinder area×stroke length in inches ÷231×60÷time in seconds for one stroke
Fluid Pressure in PSI Required to Lift Load (in PSI):
You’ll use the formula: Pounds of force needed ÷cylinder area

3. Hydraulic Motor Calculations

Consider the following key equations:
GPM of Flow Needed for Fluid Motor Speed:
Adopt the following formula: Motor displacement ×Motor RPM÷231
Fluid Motor Speed from GPM Input:
Use this formula: 231×GPM÷Fluid motor displacement
Fluid Motor Torque from Pressure and Displacement:
You’ll use this formula: PSI×Motor Displacement ÷(2×π)
Fluid Motor Torque from GPM, PSI and RPM:
You will use the formula: GPM×PSI×36.77÷RPM
Fluid Motor Torque from Horsepower and RPM:
Use this formula: Horsepower×63025÷RPM

4. Fluid and Piping Calculations

To calculate: Velocity of Fluid through Piping
Use the following formula: 0.3208×GPM÷Internal area
NOTE: For a more practical application of these formulas, you can download Target Hydraulics’ Hydraulic Calculations PDF.
Of Course, you’ll have to consider various hydraulic pipe designs and size, alongside other components such as manifolds and valves. There is the recommended pressures for each pipe.
Again, this calculations may involve some unit conversions. They are all indicated in the hydraulic calculations pdf.
Apart from these, you can visit the e4 Training. They offer a wide range of hydraulic system design calculators, simulations and courses.
With all these in mind, you can go ahead to design your hydraulic power pack circuit. This should be based on accurate calculations and selection of the right hydraulic power pack component.