Under normal circumstances, the needle globe valve’s seat hole size is smaller than the pipe size. Moreover, the thread pitch of the stem thread of the needle-type globe valve is smaller than that of the stem thread of the general globe valve. It has a high precision needle-shaped probe matched with valve seat. The valve disc and stem are usually integrated. The needle type globe valve is used for precise flow control. This type of valve is widely used in urban construction systems, water and steam pipelines in urban heating system. The disadvantage is the slow open/close speed.
The advantages of plunger globe valve are reliable sealing, long life span and easy maintenance. The valve material combination is carbon steel for the body, Cr13 stainless steel for the plunger, and flexible graphite for the sealing ring, which can be used for water, steam, oil pipelines if the body and the plunger is made of stainless acid-resistant steel, with PTFE seal ring, it is suitable for acid and alkali corrosive medium. The two spring loaded seal rings are separated by a collar, and the load applied to the bonnet through the connecting bolts of the valve body and the bonnet presses the spring-loaded seal ring around the plunger firmly to ensure the tight sealing. This type of plunger valve is a radial seal, which is realized by two spring loaded sealing rings sleeved on the polished plunger. It is suitable for media which require vacuum circumstance such as steam, flammable, explosive, thermal oil, high purity, toxic and atc The bellows are welded to the stem to maintain stable operation performance, to avoid stem vibration caused by valve plug vibration. If the bellows fails, the stem packing will act as secondary seal. The other end of bellow is installed between the valve body and bonnet to form a static seal. The bellows globe valve uses a bellows structure, and the lower end of the stainless-steel bellows is welded to the valve stem to prevent the process fluid from corroding the valve stem. It is designed by automatic roll welding to form a metal barrier between the fluid medium and the atmosphere to ensure zero leakage of the valve stem. Therefore, this type of valve is most suitable for use in synthetic ammonia production systems and refrigeration systems in chemical fertilizer plants.īellow globe valve is also called bellow seal globe valve. The biggest advantage of the angle globe valve is that the valve can be installed at the right angle of the pipeline system, which saves 90° elbows and is easy to operate. It is very suitable for alumina production pipelines, and is also suitable for pipelines with slurry medium. The sealing surface of the valve seat and disc can be welded with hard alloy for erosion and corrosion resistance. It is the smallest flow resistance among globe valve. Y type globe valve will not change the direction of flow. The split body type Y globe valve uses two valve bodies to sandwich the valve seat between them, which is convenient for maintenance. The valve body can be made integral or split body. The valve stem and the flow path of the Y type globe valve form a certain angle, and the sealing surface of the valve seat and the inlet and outlet flow path also have a certain angle. It is the most commonly used valve in the industry. Compared to gate valve, the structure of the globe valve is straight forward, and it is easier to maintain. The degree of throttling height is minimum and the process performance is optimum. During the open/close process, the friction between the sealing surfaces is small, minimizing wear and tear. It relies on the valve stem to navigate the valve disc towards the sealing surface of the valve seat, fully shut off the flow. This design has low coefficient of flow and pressure drop. The medium inlet and outlet flow path of the T Pattern Globe valve are 180° in the same direction. Straight through flange globe valve ※ Straight Through/TEE Pattern/Z-Body Globe Valve Common problems and maintenance of globe valveġ. Performance and Application of Globe ValveĦ. Construction of a Globe valve and Working Principlesģ. The valve disc and the valve stem of the globe valve are designed flexible connection to facilitate the valve disc and the valve stem fitting.Ģ. In order to close the valve tightly, the matching surface of the valve disc and the valve seat should be grinding, and the corrosion-resistant and wear-resistant materials such as Stellite 6 and stainless steel can also be welded on the sealing surface. The valve disc and the valve seat is the sealing parts of the globe valve. The most commonly used is in chemical production. The Globe valve is used to cut off the flow of the medium and is suitable for occasions that need to be throttled frequently.
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