What is the primary function of the lantern ring in a centrifugal pump?

The primary function of the lantern ring in a centrifugal pump is to cool and lubricate the packings. The lantern ring is typically located in the packing chamber and serves as a conduit for the seal water or lubricant that is directed into the packing area. This flow helps to prevent overheating of the packing material due to friction during operation and reduces the occurrence of leaks by ensuring that there is a continuous supply of coolant or lubricant. Proper lubrication is crucial for maintaining the integrity of the packing, thereby extending its service life and ensuring effective sealing around the pump shaft.

In contrast, while preventing shaft wear is a function of proper packing and sealing, it's not the primary role of the lantern ring itself. The lantern ring does not increase water pressure; that is achieved by the design of the pump impeller and its operation. Lastly, the lantern ring does not connect the motor to the pump; that connection is made through other mechanical components, such as the pump shaft and couplings. The focus on cooling and lubricating the packing highlights the lantern ring's importance in maintaining effective pump operation and reliability.