Selection and Sizing of Vacuum Pumping Systems

How To Size the Right Vacuum Pump/System: 

• • • Start from mass flow rate ‘m’ of process vapour/gas/air leakage load for a particular example.
    • Convert ‘m’ into throughput in mbar.cubic metre/hour, ‘Q’.
    • Divide ‘Q’ by the process operating pressure, to get the effective pumping speed of the chamber, Seff.
    • Calculate the conductance ‘C’ of interconnecting pipe using Hagen Poiseuille law
    • Calculate the pumping speed at the pump inlet taking ‘Seff’ and ‘C’ in cubic metre per hour unit.
    • Add 25 per cent (Saftey)to get the maximum pumping speed of the pumping module. In our case, the combination of a suitable roots blower and matching screw pump is the desired one.
    • Compute pressure drops across the pre condenser and filter, if any. Include these aspects to obtain a realistic Smax of pumping module.
    • Finalise process and control instrumentation to dynamically tune the pumping process with fluctuating process loads.
    • Design the variable drives to the pumps depending on duty cycling of pumps to save the electrical power requirement on a servo continuous basis using AI controllers connected to suitable sensors and fuzzy logic programmes
    • Monitor the process and status of various sub-units of vacuum pumping module using mimic diagrams and digital/graphical displays on a dedicated computer monitor integrated into the pumping module.
    • List possible downtimes due to unavoidable process variations in actual applications.
    • Schedule energy audit and maintenance activity at regular intervals.
    • List out important parameters like electrical power required, amount of chilled water required, steam requirement and space requirement.
    • Initiate precautionary measures to avoid situations arising due to high pressure, high temperature, high voltage and fire-related accidents without switching off the entire system.

Apart from the above-mentioned points, few aspects need to be taken care of during the initial discussion with the client. They are listed below as follows:

• • • Get inputs from customers for finalizing the accessories, vacuum pumping module and making cost at the best competitive price.
    • Win the confidence of customers with our design capabilities, installation expertise and efficient after-sales service and make them feel that we are their helping partner all the time.
    • Convince the customer that we can participate in their process optimization studies with full confidentiality.