The standard pump on all Lytron cooling systems
is a positive displacement pump. Centrifugal and turbine pumps are also offered to precisely match your application needs.
Positive Displacement Pumps
Positive Displacement pumps provide a constant flow rate regardless of pressure drop across the system. This makes them ideal if you have a high system pressure drop, require a constant flow rate regardless of changes in your system's pressure drop, or are likely to use the cooling system with a variety of test set-ups. Lytron's PD pumps are fitted with a pre-set 90 psi¹ pressure relief valve to ensure safety cut-out in the event of blockages in the system. It is recommended that PD pumps are replaced approximately every 7,000 hours of operation to ensure reliable performance.
Centrifugal and Turbine Pumps
The output of a centrifugal or turbine pump varies considerably with pressure drop across the system. If the pressure drop across the system changes, the flow rate from the cooling system will also change. A centrifugal pump is suitable for small pressure drops; a turbine pump operates at higher pressure drops. If you are considering using a centrifugal or turbine pump you should verify that the flow rate is sufficient with your system's pressure drop. It is recommended that centrifugal and turbine pumps are replaced approximately every 28,000 hours of operation to ensure reliable performance.
Calculating Flow Rate
To calculate the flow rate for a centrifugal or turbine pump, you need to know the pressure drop in your system. You then can use the appropriate pump graph to estimate flow rate.
You need a 60 Hz RC011 chiller with a flow rate of 1.5 gpm and you want to know if a centrifugal pump (the DA pump) will have sufficient flow rate. The pressure drop from the laser in your system is 30 psi at 2 gpm. Mark the graph at the intersection of these points. Draw a straight line from the origin to this point, and where it intersects the pump curve is your likely flow rate. Note that this is an approximation as flow rate is not strictly linear.
In this case, the likely flow rate with a DA centrifugal pump would be 1.9 gpm. This is higher than the 1.5 gpm required, so this pump would be a good choice. If a higher flow rate was required, a PD pump or the EB turbine pump could be considered.
The flow rate should be matched to your application to ensure that your overall system performs as expected. Pump graphs are located along side the performance graphs for each product.
¹Other settings available on request