Assuming that the channel diameter in a valve body is different (usually the diameter at the valve seat is smaller than that at the flange connection), it is called path shortening.

通徑縮短能使零件尺度減小，開、閉所需力相應減小，一起可拓展零部件的運用規劃。

Reducing the drift diameter can reduce the size of parts and the force required for opening and closing. Together, it can expand the application planning of parts.

通徑縮短后。流體阻力丟掉增大。

After reducing the drift diameter. Fluid resistance increases.

在某些有些的某些工作條件下（如石油有些的輸油管線），不允許選用通徑縮短的閥門。這一方面是為了減小管線的阻力丟掉，另一方面是為了避免通徑縮短后給機械清掃管線構成阻礙。

Under certain working conditions (such as oil pipelines), it is not allowed to select valves with shortened diameter. On the one hand, it is to reduce the resistance of the pipeline, on the other hand, it is to avoid the obstruction to the mechanical cleaning of the pipeline after the diameter is shortened.

閘 閥是作為截止介質運用，在全開時悉數流轉直通，此時介質工作的壓力丟掉更小。閘閥通常適用于不需要常常啟閉，而且堅持閘板全開或全閉的工況。不適用于作為 調理或節約運用。關于高速活動的介質，閘板在有些翻開情況下可以致使閘門的振動，而振動又可以危害閘板和閥座的密封面，而節約會使閘板遭受介質的沖蝕。 從規劃方法上，首要的區別是所選用的密封元件的方法。根據密封元件的方法，常常把閘閥分紅幾種不一樣的類型，如：楔式閘閥、平行式閘閥、平行雙閘板閘閥、楔 式雙閘板閘等。更常用的方法是楔式閘閥和平行式閘閥。

The gate valve is used as the cut-off medium. When it is fully open, all flow through. At this time, the working pressure of the medium is the minimum. Gate valves are usually suitable for working conditions that do not need to be opened and closed frequently and insist on full opening or full closing of the gate. Not suitable for conditioning or economical use. With regard to the medium moving at high speed, the ram can cause the vibration of the gate in some cases, and the vibration can endanger the sealing surface of the ram and valve seat, and the RAM will be eroded by the medium. In terms of planning method, the primary difference is the method of sealing elements selected. According to the method of sealing elements, gate valves are often divided into several different types, such as wedge gate valve, parallel gate valve, parallel double gate valve, wedge double gate valve, etc. The most common methods are wedge gate valve and parallel gate valve.

這種類型的閥門的作用是只允許介質向一個方向活動，而且阻撓方向活動。通常這種閥門是自開工 作的，在一個方向活動的流體壓力作用下，閥瓣翻開；流體反方向活動時，由流體壓力和閥瓣的自重合閥瓣作用于閥座，然后堵截活動。其間止回閥就歸于這種類型 的閥門，它包括旋啟式止回閥和升降式止回閥。

The function of this type of valve is to allow the medium to move in only one direction and block the direction. Usually, the valve is self opening. Under the action of fluid pressure moving in one direction, the valve disc opens; When the fluid moves in the opposite direction, the fluid pressure and the self weight of the valve disc act on the valve seat, and then block the activity. Meanwhile, the check valve belongs to this type of valve, including swing check valve and lift check valve.

旋啟式止回閥有一 介鉸鏈安排，還有一個像門一樣的閥瓣安閑地靠在傾斜的閥座表面上。為了確保閥瓣每次都能抵達閥座面的適合方位，閥規劃在鉸鏈安排，以便閥瓣具有滿意有旋啟 空間，并使閥瓣真實的、悉數的與閥座觸摸。閥瓣可以悉數用金屬制成，也可以在金屬上鑲嵌皮革、橡膠、或許選用構成覆蓋面，這取決于運用功能的需要。旋啟式 止回閥在徹底翻開的情況下，流體壓力幾乎不受阻撓，因此通過閥門的壓力降相對較。

The swing check valve has a hinged arrangement and a valve disc like a door resting comfortably on the inclined seat surface. In order to ensure that the valve clack can reach the appropriate orientation of the valve seat surface every time, the valve is planned to be arranged on the hinge, so that the valve clack has a satisfactory swing space and makes the valve clack truly and fully touch the valve seat. The valve disc can be made of metal, or inlaid with leather and rubber on the metal, or selected to form the coverage, depending on the needs of the application function. When the swing check valve is completely opened, the fluid pressure is almost unimpeded, so the pressure drop through the valve is relatively low.

升降式止回閥的閥瓣位于位于閥體上閥座密封面上。此閥門除了閥瓣可以安閑 地升降以外，其余有些如同截止閥一樣，流體壓力使閥瓣從閥座密封面上抬起，介質回流致使閥瓣回落到閥座上，并堵截活動。根據運用條件，閥瓣可以是全金屬結 構，也可以是在閥瓣架上鑲嵌橡膠墊或橡膠的方法。像截止閥一樣，流體通過升降式止回閥的通道也是狹窄的，因此通過升降式止回閥的壓力降比旋啟式止回閥大 些，而且旋啟式止回閥的流量遭到的束縛很少。

The disc of the lift check valve is located on the sealing surface of the valve seat on the valve body. Except that the valve disc can rise and fall freely, others are like stop valves. The fluid pressure lifts the valve disc from the sealing surface of the valve seat, and the medium backflow causes the valve disc to fall back to the valve seat and block the activity. According to the application conditions, the valve disc can be an all metal structure or a method of inlaying rubber pad or rubber on the valve disc frame. Like the stop valve, the passage of fluid through the lift check valve is also narrow, so the pressure drop through the lift check valve is larger than that of the swing check valve, and the flow of the swing check valve is less constrained.