Valve packing is held in place between the stem, gland and bonnet by the packing nut.

Valve packing is held in place between the stem, gland and bonnet by the packing nut.

• A. False
• B. True
• C. It is held by the stem.
• D. It is held by the bonnet.

Answer: (B)

The key idea is how a valve seals around its stem. The packing sits in the stuffing box around the stem, between the stem, the gland, and the bonnet, and the packing nut provides the clamping. When you tighten the packing nut, it presses the gland toward the bonnet, compressing the packing rings around the stem. This compression holds the packing in place and creates a tight seal to prevent leakage along the stem. Neither the stem nor the bonnet alone secures the packing; the nut’s compression through the gland is what holds and seals it.

The key idea is how a valve seals around its stem. The packing sits in the stuffing box around the stem, between the stem, the gland, and the bonnet, and the packing nut provides the clamping. When you tighten the packing nut, it presses the gland toward the bonnet, compressing the packing rings around the stem. This compression holds the packing in place and creates a tight seal to prevent leakage along the stem. Neither the stem nor the bonnet alone secures the packing; the nut’s compression through the gland is what holds and seals it.