What device compresses tightly around a pump shaft by applying even pressure?

• A. Throttle valve
• B. Packing gland
• C. Pump casing
• D. Pressure gauge

Answer: (B)

The packing gland is a critical component in pump design, serving an essential function in preventing leakage along the pump shaft. It consists of a series of packing materials held in place by a compression mechanism, which applies uniform pressure around the shaft. This tight compression creates a seal that minimizes the escape of the fluid being pumped, thus enhancing efficiency and preventing the loss of product or contaminants entering the pump.

The design of the packing gland allows it to accommodate slight movements of the shaft while maintaining its sealing capabilities. This feature is particularly important in applications where pumps are subject to vibrations or shifts in alignment. The packing material can be made from various materials, such as rubber or graphite, providing flexibility in how the gland performs under different conditions.

In contrast, other devices listed do not serve the same sealing or support function. For instance, a throttle valve regulates flow rather than sealing it, the pump casing houses and protects the pump components, and a pressure gauge measures the pressure within the system but does not contribute to sealing or compression around the pump shaft.