1) Suitable for opening-closing pipeline system
2) Full circulation-low pressure drop
3) Two-way
Disadvantage
1) Cannot be used for throttling; can only be used for fully open or fully closed
2) Metal-to-metal seat means that it is not suitable for frequent operation.Metal-to-metal construction is also not suitable for non-bubble valve seats
3) Difficult to control automatically
Wedge and valve seat structure
1) Solid wedges are the best choice for all building piping systems.Modern casting technology and machining process make solid wedge plate work well in many piping systems.
2) The structural form of solid metal wedge valve seat versus metal valve seat on the valve body is the most common application in building piping systems.Rubber-coated solid wedge plates (elastic wedge plates) are becoming more and more popular in fire fighting systems and municipal cold water piping systems.The elastic wedge structure has a bubble-free valve seat sealing function, but the maximum water temperature cannot exceed 71oC.
Stem structure
1) The rising rod-internal thread structure is the most common and preferred structure for bronze multi-turn valves.In the fully opened "rear seat" state, the valve stem thread can avoid contact with the fluid medium.When the valve is opened, the valve stem rises, so there must be enough space where the valve stem rises to prevent damage to the surface of the valve stem.The position of the valve stem indicates that the valve is open or closed.
*It is not recommended to add packing when the valve pressure increases.
2) Concealed rod-internal thread structure is used for bronze and cast iron gate valves.This structure is more compact than the rising stem, and the thread of the valve stem is always exposed to the fluid medium and is susceptible to erosion or corrosion.The valve of this structure cannot display the open/closed state.
3) Rising rod-external thread and bracket structure are the preferred structures for cast iron multi-turn valves.Because the thread is located outside the valve, it is beneficial to prevent corrosion by fluid media and facilitate the filling of lubricating oil.When the valve stem rises, pay attention to enough space above the valve stem to prevent the thread from being damaged.The height of the valve stem can indicate that the valve is open or closed.
Valve body-bonnet connection method
1) Pipe joint bonnet: For bronze multi-turn valves in building piping systems, pipe joint bonnet is a recommended structure, but not all types of valves require this structure.The pipe joint bonnet has a certain strength and is easy to install and disassemble.
2) Screw-in bonnet: usually used in light-duty piping systems and small-size bronze multi-turn valves.
3) Bolt body type bonnet: more cast ironRotary valveThe main structural form.This padded connection is sturdy and durable, and easy to install and remove.