Variable frequency drives (VFDs) adjust the pressure or flow on pumps to meet the actual demand. VFDs control the frequency of electricity delivered to pumps and fans. VFDs can provide significant power savings by controlling the rotational speed and frequency of electrical power supplied to the pump motor. VFDs are also referred to as variable speed drives (VSDs), adjustable frequency drives, AFDs, AC drives and inverter drives.
VFDs are commonly used on many pumps, compressors, and machine tool drives to provide significant energy savings. Adjusting pressure or flow to match the actual system demand reduces power consumption and provides energy savings.
Ultrafiltration, Reverse Osmosis and VFD Solutions
Removing particles from water is a critical process in many water treatment applications to produce clean water for various uses. Ultrafiltration processes remove particles as small as 0.01 μm, a micron, such as various suspended solids and even bacteria. Grundfos offers pumping solutions with variable frequency drive technology to provide high performance and cost-saving efficiencies. VFDs are not new to membrane filtration pumps. The most common uses of VFDs on pressure pumps are for ultrafiltration and reverse osmosis.
Challenges with Ultrafiltration Processes
Some of the biggest challenges facing ultrafiltration processes include:
- The demand for clean water changing
- The conditions of raw water changing, such as an increase in turbidity
These challenges can be addressed in a smooth and reliable manner with modern pumps and process equipment. The process must provide an efficient manner of handling changes in flow rates without providing a detrimental effect on economics or the environment.
VFD Pump Solutions for Water Treatment UF And RO
Grundfos pumps provide pumping solutions for many water treatment ultrafiltration (UF) and reverse osmosis (RO) applications. Traditional pumping solutions for UF and RO applications often utilized fixed speed pumps with throttling valves that have been proven to require extra maintenance and be quite wasteful in terms of energy, proving to be less cost-efficient. Digital pump control technologies allow operators to closely monitor the operation and system and provide more control over required dosing and flow in an economical and cost-efficient method.
Pressure Stability with Flow Variability
Process pumps and equipment must account for the water supply variability required with an ultrafiltration system. A high degree of variability could occur despite designating fixed flow units. Water supply restrictions, process fluctuations, and even seasonality may cause variations. Implementing the right type of drives such as a VFD can provide controlled flow without wasting energy. A variable frequency drive can enable reliable pressure control despite changes in discharge pressure or water supply.
Pump and Process Equipment System Design
The design and choice of pumps and process equipment significantly impact energy usage and performance. A basic law of pumps and motors understood by all is that you decrease energy consumption to the third power by reducing motor speed. When users decrease flow on a fixed speed pump with the throttling valve, this typically wastes energy and is exacerbated by using oversized pumps. Throttling typically makes pumps less efficient and consumes more power. A VFD allows users to achieve exact pressure and flow requirements while saving energy for improved efficiency.
Illinois Process Equipment, IPE, offers Grundfos pump solutions and complete process equipment system design, installation, and testing.
IPE is the leading Midwest distributor for Grundfos pumps, offering quality pumps, process equipment, and complete system design. We stand apart from other pump suppliers with our technical expertise and comprehensive services to ensure the highest quality and most efficient pump process installation. Contact us to learn more about Grundfos pumps and the many benefits of variable frequency drives.
