How much leakage is acceptable from a packing gland?

In the context of a packing gland, which is used to create a seal around a rotating shaft to prevent fluid leakage, the acceptable amount of leakage is often measured in drops per second. One drop per second generally indicates that the packing is functioning adequately while still allowing for some slight leakage that can occur as part of normal operation.

This rate of leakage allows for the necessary lubrication of the packing material, ensuring that it does not overheat or wear down too quickly due to friction. Excessive leakage would indicate that the packing is either worn out or improperly installed, which could lead to more significant operational issues.

A drop per second is typically considered a manageable level that permits continued operation without major environmental concerns or loss of efficiency. In contrast, the other options represent rates of leakage that may be too low for effective operation in many applications. For example, one drop per day or hour would likely indicate a lack of sufficient lubrication and could lead to premature failure of the packing.