Whenever a single centrifugal fan inside the system cannot deliver sufficient air flow and pressure or maybe the fan is simply too large to set up within the preferred space, then multi-stage fan systems are utilized as a substitute for single fan system. Several separate centrifugal fans could be operated in both series or perhaps in parallel plans for everyone specific needs of commercial applications. When an elevated volume or pressure is needed for any process applications, multiple fans systems may be used in both series or parallel operation instead of simply replacing the initial fan with bigger capacity. Using centrifugal fans in multiple fan plans offer greater versatility in unit sizing as well as lessen the system noise.
Centrifugal fans in series operation
In series operation, fans are set up in series near to one another as with push-pull arrangement, so the first fan in series supplies air pressure in to the inlet from the second fan. When the fans have a similar system resistance, then together they create a greater pressure difference.
In series operation, each fan may have different inlet pressures. Because the first fan pressurizes the gas before offering it towards the inlet from the second fan, there’s a rise in the particular weight from the gas in the inlet from the second fan. Accordingly, the 2nd fan in series are experiencing greater pressure differential over the system and draws greater shaft power compared to first fan.
The environment pressure does not simply double when two fans with similar capacity are operated in series arrangement. However, by organizing two fans in series, the static pressure capacity of the given air flow could be elevated. Because the individual performance of every fan isn’t the same, the fans will handle exactly the same mass air flow although not volumetric flow rate.
Series arrangement is appropriate to high resistance systems, which have lengthy ducts or large pressure drops across system components.
When fans are coupled in series, it’s not better to run one fan using the other off because the pressure drop across it’ll make another fan inefficient.
Centrifugal fans in parallel operation
Unlike series operation where typically two fans are participating, parallel operation use multiple fan systems arranged together alongside. In parallel arrangement of two fans, each fan is chosen for 1 / 2 of the look flow rate.
Parallel configurations are achievable for systems with large alterations in air gas moving needs. When fans have been in parallel, the combined performance of fans can lead to rise in the level of air flow.
The greater the machine resistance, the lesser would be the grow in air flow rate. Hence, parallel configurations commonly are not suggested for top-resistance systems. Parallel plans are appropriate for applications where fans can be employed in a minimal resistance almost inside a totally free condition.
To attain better efficiency, fans in parallel system should be correctly sized, should start concurrently and introduced up to date in the same rate. For manipulating the air flow requirement, fans in parallel can utilize additional equipment for example dampers, variable speed drives or variable inlet vanes.
