Which component of a pump is allowed to leak in a facility's transfer area?

In the context of a facility's transfer area, packing glands are specifically designed to allow for controlled leakage. Packing glands are utilized to create a seal around the rotating shaft of a pump. They achieve this by using a series of packing materials that compress against the shaft as it rotates, which prevents fluid from escaping. However, a small amount of leakage is intentional and acceptable with packing glands; it helps lubricate the packing and prevents it from overheating. This allows for effective operation while also minimizing the risk of damaging the pump.

In contrast, valves, seals, and filters are not designed to leak. Seals are intended to maintain a watertight or airtight connection and prevent any fluid migration, while valves are used to control fluid flow without the intention of allowing leaks. Filters are meant to purify the fluid by trapping particulates, and any leakage would compromise their functionality. Thus, the appropriate answer recognizes that packing glands are the only component where controlled leakage is permissible in this scenario.