A gate valve is also referred to as a sluice valve. It is a valve that opens a round or a rectangular gate out of the fluid path so that the flow can be in a specific direction. The unique feature o this valve is the presence of a planar sealing surface existent in between the gate and the seats. The gates can be parallel too. These conventional gate valves should never be used to regulate the flow of the fluid unless designed to do so. The other feature of the gate valve is that the flow rate of the fluid does not change in proportion to the stem travel.

Gate valve is mainly used for the purpose of being completely open or being completely closed. If they are partially opened then there is a tendency of a vibration from the flow of the fluid. There might be a comparatively high rate of the fluid flow with a greater rate of velocity of the fluid leading eventually to a leakage. This is the reason why this type of a valve is not used for the purpose of only regulation of the flow of the respective fluid. Again when the gate valve is completely opened there can be smooth fluid flow as this way the flow of the fluid does not have any obstruction and there will be very less loss due to the above mentioned.

Gate valves have either a stem which is rising or a stem which is non rising. The rising stems of these types of valves are indicators of the position of the relevant valve and the use of the nom rising stem gate valve simply occurs where there is limited space or underground space for operation of this type of a valve.

As far as bonnets are concerned these valves have:

Bolted Bonnets: which is mainly used for larger and high pressure applications or Screwed In Bonnets: This is simplest form of bonnet present in the gate valve and this is durable and also possesses seal which pertains to the pressure maintenance.

Union Bonnet: This is principally favorable to the uses requiring cleaning and checking.

Pressure Seal Bonnet: This is mainly for the valves for high pressure services. The peculiar feature in the pressure seal bonnet is that the seal improves when there is an increase in the internal pressure of the valve.

The composition of the gate valves is cast iron, cast carbon and steels in all its various forms.