1. Once the valve disc of the globe valve is in the open state, its seat and the sealing surface of the disc are no longer in contact, so its sealing surface is less mechanical wear, but if the medium contains solid particles, it is easy to damage the sealing surface.2. On the sealing surface of the globe valve, the valve that must be closed by force can be sealed. Under the same caliber, working pressure and the same driving device, the driving torque of the globe valve is 2.5~3.5 times of the gate valve.This point should be paid attention to when adjusting the torque control mechanism of electric valve.
The sealing surface of the globe valve only contacts each other when it is completely closed. The relative slip between the forced closing valve core and the sealing surface is small, so the sealing surface wear is also small.The wear of the sealing face of the globe valve, most of it is caused by debris before the valve core and sealing face, or due to the close state of the loose, caused by the medium of high-speed erosion.
3. When the globe valve is installed, the medium can enter from the lower part of the spool and from the upper part.The advantages of media entering from the lower part of the spool are that when the valve is closed, the packing is not subjected to pressure, which can extend the service life of the packing, and can be used to replace the packing under the pressure of the pipeline in front of the valve.Medium from the bottom of the valve core into the disadvantage of the valve drive torque is large, about the top into the 1.05~1.08 times, the axial force of the stem by the big, easy to bend the stem.For this reason, the medium from the bottom into the way, generally only suitable for small diameter globe valve (DN50 below), DN200 above the globe valve are selected from the medium inflow from the top way.Electric globe valve is generally the use of media from above into the way.The disadvantage of the medium entering from above is just the opposite of the medium entering from below.The flow direction of the gate valve is the same from both sides.
Compared with gate valve, globe valve has the advantages of simple structure, good sealing performance and convenient manufacturing and maintenance.The disadvantage is the liquid resistance, opening and closing force.
Gate valve maintenance is not suitable for field piping, and most globe valve seats and discs can be replaced online without removing the entire valve from the pipeline, which is suitable for valve and pipeline welding into one.
4. Purpose of globe valve
Globe valves can be used in most media flow systems.Various types of globe valves have been developed for various USES in petrochemical, electric power, metallurgy, urban construction and chemical engineering sectors.
The use of globe valve is very common, but due to the opening and closing torque is large, the structure length is long, usually nominal diameter is limited to 250mm below, also to 400mm, but the choice of the need to pay special attention to the import and export direction.Generally, the globe valve medium below 15Omm mostly flows in from the lower part of the disc, while the globe valve medium above 2O0mm mostly flows in from the upper part of the disc.This is due to the consideration of valve closing torque.In order to reduce the opening or closing torque, generally 2O0mm more than the globe valve are equipped with an internal bypass or external bypass valve.
Main parts material
|Type||Main form and the connection size(mm)||Nominal pressure||Scope of pressure adjustment|
|Applicable medium||LNG ,LO2,LN2,Lar|
|Connection method||Thread/butt welding|
>>Connecting dimension and ste pressure may be according to user's request
Frequently asked questions
Q: what kind of express do you send?
A: The normal situation is DHL, if you have other needs, you can contact our salesman.
Q: how long is your delivery time?
A: Normally, the relief valve takes 7 days and the other valves take 45 days.
Q: is it possible to customize the valve?
A: Yes, please contact our salesman for specific size and specification.
Shanghai AFS Valve Manufacturing Co., Ltd.
Web site: http://afsvalve.en.made-in-china.com