Tuesday, September 30, 2008

Hydraulic Reservoir or Tank Size Calculation

Hydraulic Reservoir design and implementation is very important in hydraulic systems as the efficiency of a well-designed hydraulic circuit can be greatly reduced by poor tank design. In addition to fluid storage, a well-designed reservoir also dissipates heat, allows time for contamination to drop out of the fluid, and allows air bubbles to come to the surface and dissipate. It may give a positive pressure to the pump inlet and makes a convenient mounting place for the pump and its motor and valves.

The accepted rule for sizing a tank = (3 to 5) X Q
Where 'Q' is the pump discharge rate.
This will allow sufficient time for oil to cool down before recirculation into the circuit. Also, include one or two baffles inside the tank to increase the path of fluid for better cooling.
Also, you need to check the heat dissipation capacity of tank with above calculated sizes to make sure it is sufficient enough to cool down the oil.

Head Dissipation, HD = 0.001 x (T1 - T2) x A
Where
T1 = max. allowable fluid temperature (in degree F)
T2 = max. ambient air temperature (in degree F)
A = area of tank in contact with fluid (in sq. ft)

Heat dissipation is the main reason for having tank surfaces exposed to free air for better cooling.

I hope these two checks will be enough for a basic hydraulic tank design.

With best wishes,
Krish

Labels:

Monday, September 8, 2008

What is Synchronous Technology in CAD ?

Synchronous technology is a latest development in digital product design introduced by Siemen's PLM software. It provides the first history-free, feature-based modeling technology that accelerates design process.

Parametric feature-based modeling is very powerful in editing and modifying CAD models, but it does not help much in case of dump solids or imported models from other CAD software. In this case, the essential method was direct editing (also known as explicit modeling).

Synchronous technology combines the best of constraint driven techniques with direct modeling methods. The unparametric models imported from other software can be edited quickly. The CAD user can take an existing model (native or imported), make changes to it with no limitations from the history tree, and add new intelligence (constraints and driving dimensions) to the model. Model reuse and editing will be faster and simpler even for a less skilled CAD operator.

The word “synchronous” doesn’t refer to a modeling process, but refers to a computer algorithm which solves a group of mathematical equations known as “synchronous solver”.

Sequential solvers are the oldest and simplest type. They have the limitation of order dependency.

Simultaneous solvers are more advanced used in today’s parametric feature based modelers. They solve all equations representing the constraints (including relationships and dimensions) defining a feature simultaneously, as a group.

Siemen’s synchronous solver overcomes the order dependencies by solving for the explicit and inferred constraints at the same time. This solver doesn’t use a history tree, but rather holds user-defined constraints in groups associated with the surfaces o which they apply.

The synchronous solver does a lot more than a typical simultaneous solver.


Jythra Engineering Services
___________________________________________