Advantages of shut-off valves
a. Compared with the gate valve, the structure of the globe valve is simpler, usually with only one sealing surface on the valve body and valve flap, a small sealing area, saving valuable materials, and a low cost, thus the manufacturing process is better and easier to maintain.
b. The sealing surface wear and abrasion are light, and good sealing. No relative sliding between the valve flap and the valve body sealing surface when opening and closing (except for the conical sealing surface), so wear and abrasion are not serious, have good sealing performance, and have a long service life.
c. Small opening height, generally only 1/4 of the diameter of the valve seat channel, compact structure, saving installation controls.
Disadvantages of shut-off valves
a. Large structure length.
b. Opening and closing torque is large, and the opening and closing effort are. When closing, because the direction of movement of the valve flap is opposite to the direction of the medium pressure, the force of the medium must be overcome, so the opening and closing torque is large.
c. Large flow resistance. The Media channel inside the valve is more tortuous, with flow resistance and power consumption, especially in the hydraulic device; this pressure loss is particularly obvious. In all types of cut-off valves, the valve flow resistance Z is large.
d. The media flow direction is restricted. Media flow through the shut-off valve, at the valve seat channel, can only be from the bottom up or down, so the media can only flow in one direction, and can not change the direction of flow.
e. When the valve is closed, the sealing surface may be trapped between the fluid medium and solid particles.
f. Inconvenient installation.
