3 April 2013:
Variable Speed Pump Drives
As we have stated previously, we are going to be taking the ideas developed in this column over the last couple of years and developing them into design practices. This is how it works. We will provide the basic narrative here for one design practice each week. We will keep it open for comments for one month. After that, we will finish it in formal form and offer it for sale at a modest price. Here is where you come in. If you make a substantive contribution to a standard, the organization for which you work will be granted a pro bono license to use that standard with its current issue number for as long as you like. We have had good response so far! Contribute, please
Variable Speed Pump Drives (LGM 2013.013.01
Variable speed drives (VSD) pumps offer higher efficiencies, reduction of energy usage, elimination of control valves and bypass lines, improved process control and lower maintenance.
To use variable speed pump drives.
Motor-driven equipment accounts for approximately two-thirds of electricity consumption in the industrial sector, therefore
energy losses in the system can be reduced by improving motor efficiency for pumps.
Throttling the output with a valve that controls the (fixed speed) pump output is a common method rendering significant energy losses. Most existing pumping systems are oversized, many by more than 20%, thus providing substantial opportunity for systems optimization.
Variable speed drives (VSD) pumps offer higher efficiencies, reduction of energy usage, lower initial equipment cost, lower life cycle costs, easier control and less maintenance.
Potential use in the pulp and paper industry is to control the fan pump in the approach section. Fan pumps must also be able to vary the flow over the entire range of paper machine operation because of change in product requirements or operating conditions.
Pulp stock pumps should be chosen to run at the lowest speed possible to achieve stable operation which many not prove to be efficient. Good pump selection is primarily concerned with reliability, with efficiency and costs as secondary considerations.
As always, your comments will be appreciated.
Brian Brogdon, Ph.D.
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