Features Of Gate Valves
1. Flexible or solid wedge
2. Full-bore or reduced-port
3. Replaceable seat or integral seat
4. Bolted bonnet or self sealing bonnet
5. Rising Stem
Rising stems are fixed to the gate and they rise and lower together as the valve is operated, providing a visual indication of the valve position and making it possible to grease the stem. A nut rotates around the threaded stem and moves it. This type of valve has an inside screwed stem and the packing is subjected to wear because of the up and down movement and turning motion of the stem.