System and process requirements:Process requirements

Process requirements

In a pumping system, the operating costs can be correctly evaluated and the potential savings identified only by considering that all components of the system are interdependent.

Therefore, when examining or designing a pumping system, the process requirement must first be established under the form of a load profile or duration diagram see Figure 5.1.

Then the output control “strategy” must be selected (use of throttling valves, by-passes or VSDs) in order to match the characteristic curve of the pump to the specified system curve(s), reducing the use of energy and minimizing life cycle cost for the complete system.

In general it can be said that flow control of virtually any type of liquid can be achieved by driving the pump(s) at variable speed, instead of using throttling valves or complex by-pass devices.

However, it must be realised that the use of variable speed drives, although useful to improve the accuracy and the flexibility of process control, does not always achieve the minimum life cycle cost target.

Sections 4.2.2, 4.3.3 and 4.3.4, illustrate this subject and give guidance in selecting the most appropriate control method for pumps and motors when considering the characteristics of the system.

Related posts:

Benefits, drawbacks and operational issues:Operational issues
Selection process - new systems:Flow charts
Applied Pneumatics:Flow analysis for cylinders and valves
Applications on pneumatic:Compressed air in marine applications.
Optimizing and up-rating of existing systems:System not capable of duty
Coarse material:Procedure and Operating point.
Material property influences:Conveying capability correlations.
HYDRAULIC FLUIDS:Density and Compressibility
Sequencing Applications:logic elements
THE SECOND LA W OF THERMODYNAMICS:THE CARNOT HEAT ENGINE
ENTROPY:REVERSIBLE STEADY-FLOW WORK
POWER AND REFRIGER A TION CYCLES: THE IDEAL CYCLE FOR SPARK-IGNITION ENGINES
POWER AND REFRIGER A TION CYCLES:THE REVERSED CARNOT CYCLE
NATURAL CONVECTION:NATURAL CONVECTION INSIDE ENCLOSURES
INTRODUCTION TO FLUID MECHANICS:SURFACE TENSION AND CAPILLARY EFFECT

Leave a comment

Your email address will not be published. Required fields are marked *