分類按作用和用途
Classification by function and purpose
（一）關斷閥這類閥門是起開閉作用的。常設于冷、熱源進、出口，設備進、出口，管路分支線（包括立管）上，也可用作放水閥和放氣閥。常見的關斷閥有閘閥、截止閥、球閥和蝶閥等。閘閥可分為明桿和暗桿、單閘板與雙閘板、楔形閘板與平行閘板等。閘閥關閉嚴密性不好，大直徑閘閥開啟困難；沿水流方向閥體尺寸小，流動阻力小，閘閥公稱直徑跨度大。截止閥按介質流向分直通式、直角式和直流式三種，有明桿和暗桿之分。截止閥的關閉嚴密性較閘閥好，閥體長，流動阻力大，公稱直徑為DN200。球閥的閥芯為開孔的圓球。板動閥桿使球體開孔正對管道軸線時為全開，轉90°為全閉。球閥有一定的調節性能，關閉較嚴密。蝶閥的閥芯為圓形閥板，它可沿垂直管道軸線的立軸轉動。當閥板平面與管子軸線一致時，為全開；閘板平面與管子軸線垂直時，為全閉。蝶閥閥體長度小，流動阻力小，比閘閥和截止閥價格高。
（1） Shut off valve this kind of valve is used for opening and closing. It is always used at the inlet and outlet of cold and heat sources, the inlet and outlet of equipment, and the branch line of pipeline (including riser). It can also be used as drain valve and vent valve. Common shut-off valves include gate valve, globe valve, ball valve and butterfly valve. Gate valves can be divided into rising stem and Non rising stem, single gate and double gate, wedge gate and parallel gate, etc. The closing tightness of the gate valve is not good, and it is difficult to open the large-diameter gate valve; Along the direction of water flow, the valve body has small size, small flow resistance and large nominal diameter span of gate valve. According to the medium flow direction, the stop valve is divided into straight through type, right angle type and direct flow type, which can be divided into exposed rod and concealed rod. The closing tightness of the stop valve is better than that of the gate valve. The valve body is long and the flow resistance is large. The nominal diameter is DN200. The valve core of the ball valve is a round ball with an opening. Move the valve rod to make the opening of the ball face the axis of the pipe, which is fully open, and turn 90 ° to fully close. The ball valve has certain regulation performance and is tightly closed. The valve core of the butterfly valve is a circular valve plate, which can rotate along the vertical axis perpendicular to the pipeline axis. When the plane of the valve plate is consistent with the axis of the pipe, it is fully open; When the plane of the ram is perpendicular to the pipe axis, it is fully closed. Butterfly valve body length is small, the flow resistance is small, and the price is higher than that of gate valve and stop valve.
（二）止回閥這類閥門用于防止介質倒流，利用流體自身的動能自行開啟，反向流動時自動關閉。常設于水泵的出口、疏水器出口以及其他不允許流體反向流動的地方。止回閥分旋啟式、升降式和對夾式三種。對于旋啟式止回閥，流體只能從左向右流動時，反向流動時自動關閉。對于升降式止回閥，流體從左向右流動時，閥芯抬起，形成通路，反向流動時閥芯被壓緊到閥座上而被關閉。對于對夾式止回閥，流體從左向右流動時，閥芯被開啟，形成通路，反向流動時閥芯被壓緊到閥座上而被關閉，對夾式止回閥可多位安裝、體積小、重量輕、結構緊湊。
（2） Check valve this kind of valve is used to prevent the medium from backflow, open it by using the kinetic energy of the fluid itself, and close it automatically in case of reverse flow. Standing at the outlet of the water pump, the outlet of the steam trap and other places where the reverse flow of fluid is not allowed. Check valves are divided into swing type, lifting type and wafer type. For swing check valves, the fluid can only flow from left to right, and automatically closes in reverse flow. For the lift check valve, when the fluid flows from left to right, the valve core is lifted to form a path. When the fluid flows in the opposite direction, the valve core is pressed onto the valve seat and closed. For the wafer check valve, when the fluid flows from left to right, the valve core is opened to form a path. When the fluid flows in the opposite direction, the valve core is pressed onto the valve seat and closed. The wafer check valve can be installed in multiple positions, with small volume, light weight and compact structure.
（三）調節閥閥門前后壓差一定，普通閥門的開度在較大范圍內變化時，其流量變化不大，而到某一開度時，流量急劇變化，即調節性能不佳。調節閥可以按照信號的方向和大小，改變閥芯行程來改變閥門的阻力數，從而達到調節流量目的的閥門。調節閥分手動調節閥和自動調節閥，而手動或自動調節閥又分許多種類，其調節性能也是不同的。自動調節閥有自力式流量調節閥和自力式壓差調節閥等。
（3） The pressure difference between the front and back of the regulating valve is certain. When the opening of the ordinary valve changes in a large range, the flow changes little, while when it reaches a certain opening, the flow changes sharply, that is, the regulation performance is poor. The regulating valve can change the resistance number of the valve by changing the spool stroke according to the direction and size of the signal, so as to achieve the purpose of regulating the flow. The regulating valve is divided into manual regulating valve and automatic regulating valve, and the manual or automatic regulating valve is divided into many kinds, and its regulating performance is also different. Automatic regulating valves include self operated flow regulating valve and self operated differential pressure regulating valve.
（四）真空類真空類包括真空球閥、真空擋板閥、真空充氣閥、氣動真空閥等。其作用是在真空系統中，用來改變氣流方向，調節氣流量大小，切斷或接通管路的真空系統元件稱為真空閥門。
（4） Vacuum class vacuum class includes vacuum ball valve, vacuum baffle valve, vacuum charging valve, pneumatic vacuum valve, etc. Its function is to change the air flow direction, adjust the air flow, and cut off or connect the pipeline in the vacuum system, which is called vacuum valve.
The above is the detailed introduction of Shanghai Lianggong valve. I hope it will be helpful to you If you have any questions, please contact us We will provide service for you with our attitude http://www.kasidc.com
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