截止閥是指關閉件(閥瓣)沿閥座中線移動的閥門。根據閥瓣的這種移動形式,閥座通口的變化是與閥瓣行程成正比例關系。由于該類閥門的閥桿開啟或關閉行程相對較短,而且具有非常可靠的切斷功能,又由于閥座通口的變化與閥瓣的行程成正比例關系,非常適合于對流量的調節。因此,這種類型的閥門非常適合作為切斷或調節以及節流使用。
Stop valve refers to the valve whose closing part (disc) moves along the centerline of the valve seat. According to this movement form of the valve disc, the change of the valve seat opening is in direct proportion to the stroke of the valve disc. Because the opening or closing stroke of the valve stem of this kind of valve is relatively short, and has a very reliable cutting function, and because the change of the valve seat opening is in direct proportion to the stroke of the valve disc, it is very suitable for the regulation of flow. Therefore, this type of valve is very suitable for cut-off or regulation and throttling.
截止閥的閥瓣一旦從關閉位置移開,它的閥座和閥瓣密封面之間就不再有接觸,因而它的密封面機械磨損很小,故其密封性能是很好的,缺點是密封面間可能會夾住流動介質中的顆粒。但是,如果把閥瓣做成鋼球或瓷球,這個問題也就迎韌而解了。由于大部分截止閥的閥座和閥瓣比較容易修理或更換,而且在修理或更換密封元件時無需把整個閥門從管線上拆卸下來,這在閥門和管線焊成一體的場合是非常適用的。
Once the valve disc of the stop valve is removed from the closed position, there will be no contact between its seat and the sealing surface of the valve disc. Therefore, the mechanical wear of its sealing surface is very small, so its sealing performance is very good. The disadvantage is that the particles in the flowing medium may be clamped between the sealing surfaces. However, if the valve disc is made into steel ball or porcelain ball, this problem will be solved. Because the valve seat and disc of most stop valves are relatively easy to repair or replace, and there is no need to disassemble the whole valve from the pipeline when repairing or replacing the sealing elements, it is very applicable when the valve and pipeline are welded into one.
由于介質通過此類閥門時的流動方向發生了變化,因此截止閥的流阻也較高于大多數其他類型的閥門。然而,根據閥體結構和閥桿相對于進、出口通道的布局,這種狀況是可以改變的。同時。由于截止閥瓣開與關之間行程小,密封面又能承受多次啟閉,因此它很適用于需要頻繁開關的場合。
As the flow direction of medium passing through such valves has changed, the flow resistance of stop valves is also higher than that of most other types of valves. However, this situation can be changed according to the structure of the valve body and the layout of the valve stem relative to the inlet and outlet channels. At the same time. Because the stroke between the opening and closing of the stop valve disc is small, and the sealing surface can withstand multiple opening and closing, it is very suitable for occasions requiring frequent opening and closing.
截止閥可用于大部分介質流程系統中。已研制出滿足石化、電力、冶金、城建、化工等部門各種用途的多種形式的截止閥。
Stop valves can be used in most media process systems. Various forms of stop valves have been developed to meet various uses in petrochemical, electric power, metallurgy, urban construction, chemical and other departments.
截止閥的使用普遍,但由于開啟和關閉力矩較大、結構長度較長,通常公稱通徑都限制在250mm 以下,也有到400mm 的,但選用時需特別注意進出口方向。一般15Omm 以下的截止閥介質大都從閥瓣的下方流入,而2O0mm 以上的截止閥介質大都從閥瓣的上方流入。這是考慮到閥門的關閉力矩所致。為了減小開啟或關閉力矩,一般2O0mm 以上的截止閥都設內旁通或外旁通閥門。
Globe valves are widely used. However, due to the large opening and closing torque and long structural length, the nominal diameter is usually limited to less than 250mm, and some to 400mm. However, special attention should be paid to the inlet and outlet direction when selecting. Generally, most of the stop valve media below 15mm flows from below the valve disc, while most of the stop valve media above 2o0mm flows from above the valve disc. This is due to the closing torque of the valve. In order to reduce the opening or closing torque, the stop valves above 2o0mm are generally equipped with internal bypass or external bypass valves.
截止閥明顯的優點是:
The obvious advantages of stop valve are:
在開啟和關閉過程中,由于閥瓣與閥體密封面間的摩擦力比閘閥小,因而耐磨。( 2 )開啟高度一般僅為閥座通道直徑的l / 4 ,因此比閘閥小得多。
In the process of opening and closing, the friction between the valve disc and the sealing surface of the valve body is smaller than that of the gate valve, so it is wear-resistant. (2) the opening height is generally only L / 4 of the diameter of the valve seat channel, so it is much smaller than the gate valve.
通常在閥體和閥瓣上只有一個密封面,因而制造工藝性比較好,便于維修。但是,截止閥的缺點也是不容忽視的。其缺點主要是流阻系數比較大,因此造成壓力損失,特別是在液壓裝置中,這種壓力損失尤為明顯。
Generally, there is only one sealing surface on the valve body and disc, so the manufacturing process is relatively good and easy to maintain. However, the shortcomings of stop valve can not be ignored. Its disadvantage is that the flow resistance coefficient is relatively large, resulting in pressure loss, especially in hydraulic devices.
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