What type of leakage is primarily controlled by the packing in a pump?

The type of leakage primarily controlled by the packing in a pump is water leakage. Packing in a pump is designed to prevent water from leaking out of the pump casing at the shaft where it enters and exits. This packing serves as a seal, which helps maintain the pressure within the pump system and ensures efficient operation. Properly installed and maintained packing minimizes the exit of water, preventing loss of pump efficiency and potential environmental issues.

While air leakage, pressure leakage, and vapor leakage are relevant concerns in pumping systems, they are generally controlled by different mechanisms or components. Air leakage might be addressed by ensuring seals on suction lines are intact, pressure leakage is managed through proper design and integrity of the entire system, and vapor leakage typically involves considerations around boiling or vaporization of fluids within the system, rather than being specifically controlled by pump packing. Therefore, the primary responsibility of the packing is to minimize water leakage, making it the correct choice.