What is the difference between an open system and a closed system? Which pumps are recommended for each system?
An open system consists of a circulator and an open external bath. As the circulator pumps liquid into the external bath, liquid must also be pumped out at an equal flow rate. This prevents the bath from overflowing (see Figure 1). A pressure/suction pump or a duplex pump can be used for an open system. Pressure/suction pumps require a level controller accessory to protect against bath overflow. This is necessary because the flow rate of pressure and the flow rate of suction are never exactly equal. A duplex pump has a built-in level controller. Figure 1 A closed system includes a circulator and jacketed reaction vessel or condenser (see Figure 2). The circulating liquid is pumped through a closed loop system. A simple pressure pump is sufficient for this type of application.
