The shut-off valve is also called the shut-off valve. When the valve is closed, pressure must be applied to the disc to force the sealing surface to not leak. The globe valve is a forced sealing valve. There are also many points that need to be paid attention to in the operation of the globe valve, which are shared with you below:
Most globe valves use a T-shaped body, which allows the valve to be installed on straight-through lines. The flow enters the center of the valve through the inlet (where the spool is located). Here the flow direction turns by 90° and then passes through the valve seat, followed by another 90° turn out of the valve.
The flow direction of a globe valve is determined by the manufacturer or operating conditions, but for most applications, the flow direction is almost always below the valve plug. Place the sender against the flow direction, he has constant resistance but enough to overcome. For down-spool flow, the valve is relatively easy to close and fluid pressure and flow changes are less frequent. In addition, the downflow of the spool is easy to open due to the fluid pushing the bottom of the spool.
Manual shut-off valves can be adjusted to percent, linear, or quick-opening flow characteristics. As explained in detail in Section 2.2, the flow characteristics determine the expected flow rate (expressed as the flow coefficient CV) at a certain position of the valve. Thus, for a certain flow characteristic, the user can determine the flow rate through the linear position of the manual handwheel. If the spool head is in the throttled position (between fully open and fully closed), the flow moves towards the flow opening of the valve seat due to the pressure drop. In the throttling position, the spool head protrudes slightly into the seat ring, providing flow at a particular location for a given flow characteristic. Larger flow rates can be achieved when retracted and away from the seat. If it is further extended to the valve seat, a smaller flow is formed. As the flow moves across the valve seat, the fluid pressure decreases and the velocity increases. After the fluid enters the lower part of the shut-off valve, the flow area increases again, the pressure recovers and the flow rate decreases.
An important design consideration when fluid enters the seat or plug area of the valve is the bench area of the valve body. In a rational state, the flow circulates freely along the valve plug and valve seat, enabling the flow to enter the valve seat from every direction. If the table area is too narrow in any one area (eg on the backside of the cock), the velocity may increase causing noise and abrasion, or turbulence downstream. There are unequal forces acting on the spool head, which can cause slight deflection of the spool head if it is not guided by the seat.
When the globe valve is closed, the axial force of the handwheel acts on the cock. The force of the valve plug surface exerts pressure on the slightly mismatched angle of the seat ring without allowing any flow through the closure element. In the fully open position, the entire valve seat area is open to flow for flow.
Process streams are retained within the valve body and bonnet by the static sealing of the end fitting gaskets. The dynamic seal of the bonnet stuffing box prevents leakage of flow through the cock sliding rod. Depending on the user’s closing requirements, the flow may or may not be leaked by regulating the closing element itself.
The above content is the operation of the globe valve shared with you today. It is described from several stages, and I hope it can help you. Collect it~