Differences between Globe Valves and Gate Valves

Author:     Published time:2017-07-21 16:19     Reading times:487    

From a structural point of view:

A gate valve is shorter than a globe valve in length, and higher in height. To install rising stem gate valves, special attention should be taken for height. A gate valve can achieve air-tight sealing with the pressure of the medium. The sealing of valve core and valve seat contact and rub frequently when it opens or closes, so the valve sealing face scuffs easily. When the valve is right to be closed, there will be great pressure difference between the front and back ends of the pipe, making the corrosion of the sealing face severer.

 

In principle:

In principle, the difference between the two is that gate valve is a rising stem, whose hand-wheel will rotate and ascend with rod. Gate valve rotates by hand-wheel, and rod ascends. For different flow rate, gate valve is required to open and close fully, but the globe valve isn’t. The gate valve has standard inlet and outlet direction, but the globe valve hasn’t.

 

From the point of view of flow:

The gate valve sees lower inflow level and higher outflow level, whose pipes are not on the same level obviously. But the flow of gate valve does. The stroke of gate valve is longer than globe valve.


From the point of the view of installation:

The effect is the same when the flow enters into two sides of a globe valve.

There are two ways to install a globe valve. One is that the medium can enter from the below of valve core. The advantage is that the packing is not affected by pressure and it will increase its service life. And the packing function can be replaced when thevalve pipe before the pipe under the pressure; the disadvantage is that the rotary torque is large, about one time than the flow from the upper. The bolt is easy to bend for strong axial force. So the way is only suitable for small-bore gate valve (below DN50). The way of flowing from above can be used if the gate valve is above DN200. The electronic gate valve is usually used in the way of flowing from above. But the drawback of medium entering from the above is just the opposite of the way entering from below.

 

From the point of view of sealing surface:

 The sealing surface of a gate valve is the side of a trapezoid angle in valve core (according to its shape in practice). Once the core comes off, it means the valve is closed. If the gas pressure is quite large, the valve can’t be closed tightly. But the non-return effect is not bad. The gate valve seals itself by the side of valve core, but the sealing effect is not better than the globe valve, and the valve core dropping off does not constitute valve close like a globe valve.


Related recommendation:


ANSI B16 Metal Sealed Types Of Gate Valves

DIN3302 F4 Metal Sealed Types Of Gate Valves



Skype
Email
TOP