What device applies an even pressure to the packing in a pump?

The packing gland is designed specifically to apply even pressure to the packing material within a pump. This device is crucial for ensuring that the pump operates effectively without leaking fluid. The packing itself is typically comprised of a series of rings made from materials that can withstand the pump's operational conditions, such as temperature and pressure.

The packing gland compresses these rings against the shaft and the pump casing, creating a tight seal. This prevents the process fluid from escaping while allowing the shaft to rotate freely. Proper adjustment of the packing gland is important; if the packing is too tight, it can cause excessive wear on the shaft, whereas if it is too loose, it will lead to leaks and reduced efficiency.

In contrast, the other devices listed do not serve the same purpose. The motor base is part of the pump's support structure and does not directly interact with the packing. The drive shaft transmits mechanical power but doesn't apply pressure to packing. A flow meter measures the flow rate of the liquid passing through the system, which holds no relation to the application of pressure in the packing. Thus, the packing gland is the essential component for ensuring the appropriate sealing mechanism within the pump system.