A seal assembly for a creating a seal between a shaft and a valve housing of a bleed valve that impedes contaminants from reaching bearings includes first and second seal pieces. The first seal piece circumferentially surrounds the shaft and is disposed between the shaft and the valve housing. The second seal piece is in contact with and is disposed axially adjacent to the first seal piece relative to the shaft. The second seal piece is biased against the first seal piece.

A seal assembly for a creating a seal between a shaft and a valve housing of a bleed valve that impedes contaminants from reaching bearings includes first and second seal pieces. The first seal piece circumferentially surrounds the shaft and is disposed between the shaft and the valve housing. The second seal piece is in contact with and is disposed axially adjacent to the first seal piece relative to the shaft. The second seal piece is biased against the first seal piece.

An example apparatus is disclosed herein comprising a valve that includes a valve body defining a fluid passageway between an inlet and an outlet, a flow control member in the fluid passageway, a stem coupled to the flow control member, and a bonnet coupled to the valve body. The stem extends through a channel in the bonnet. A section of the channel forms a bore. The bore is threaded. The apparatus includes packing in the channel to form a seal between the bonnet and the stem. The apparatus includes a worm wheel nut threadably engaged with the bore. The stem extends through an opening in the worm wheel nut. The apparatus also includes a worm meshed with the worm wheel nut. The worm is to rotate the worm wheel nut to cause the worm wheel nut to move and adjust a load on the packing.