Faq

The gate valve has a double-sided forced seal:

Meaning that whether in the medium of the inlet or outlet end, the gate and seat sealing surface is sealed, sealing by the stem axial force to ensure that mandatory, when there is no medium, the positive pressure between the sealing surface shall not be less than the medium static pressure and sealing force and the sum of.

The gate valve has a one-sided forced seal:

Means in the media inlet side of the gate and the valve seat sealing surface is not sealed, here or no pressure or only than the sealing pressure for the small pressure. In the media outlet side of the sealing surface between the gate and the valve seat sealing surface is by the stem axial force and media pressure to ensure that mandatory, when there is no media, the sealing surface of the specific pressure must not be less than the sealing pressure.

（1）按闸板的构造分成两类

1. 平行式闸阀是指密封面与垂直中心线平行，即两个密封面互相平行的闸阀。平行式闸阀中又有双闸板和单闸板之分。又分为有导流孔和无导流孔。
2. 楔式闸阀是指密封面与垂直中心线成某种角度，即两个密封面成楔形的闸阀。楔式闸阀中又有双闸阀、单闸板及弹性闸板之分。

（2）按阀杆的构造分为两类

1. 明杆闸阀是指阀杆螺母在阀盖或支架上，开闭闸板时，用旋转阀杆螺母来实现阀杆的升降的闸阀。
2. 暗杆闸阀是指阀杆螺母在阀体内与介质直接接触，开闭闸板时用旋转阀杆来实现的闸阀。

阀杆最小直径指的是阀杆与填料接触部分的直径。最小阀杆直径是指阀杆螺纹退刀槽的直径。

The handle and handwheel are painted to represent the paint color of the sealing surface material, as detailed in the table below.

Valve handle and handwheel painted color:

通用阀门的启、闭方向规定为：顺时针方向为关闭，逆时针方向为开启。

The mandatory and optional symbols for general purpose valves are shown in the table below.

Valve markings:

Note: Nominal pressure casting on the valve body is equal to 10 times the number of megapascals (MPa), set in the nominal pressure value of the value below, the front is not crowned with the code “PN”.

Marking Methods:

(1) Nominal size greater than or equal to DN50 valve marking:

1. Items 1 to 4 in the table are mandatory symbols and should be marked on the valve body.
2. Items 5 and 6 of the table are mandatory markings only if provided for in the standard for a particular type of valve, and they should be marked on the valve body and flange, respectively.
3. If there are no special provisions in the standards for various types of valves, items 7 to 19 in the table are markings to be used as required. When required, they can be marked on the valve body or on the label.

(2) Marking of valves with nominal size less than DN50:

1. Items 1 to 4 in the table are the markings that must be used. Whether the marking is on the valve body or on the label is specified by the product designer.
2. The marking of the symbols 5 to 19 in the table is in accordance with the markings 2. and 3. for nominal sizes greater than or equal to DN50.

(3) Additional signs:

1. Any of the markings in the table may be attached at different locations. For example, any of the symbols located on the valve body may also be repeated on the label.
2. Any other symbols may be attached as long as the additional symbols are not confused with the symbols in the table. For example, product model number, etc.

For pressure reducing valves, in addition to the marking on the valve body in accordance with the general valve regulations of the 19 provisions, there should also be: the date of shipment, the applicable medium, the outlet pressure.

For the marking of steam traps in accordance with the provisions of GB/T 12250-2005, the marking can be located on the valve body, can also be marked on the label.

The marking of safety valves is in accordance with GB/T 12241-2005.

Ball valves, parallel gate valves, and plug valves are marked in accordance with API 6D-2014.

由阀体直接加工的密封面材料代号用“W”表示，其余材料代号见下方表格。

阀座密封面或衬里材料代号：

注：当密封副的密封面材料不同时，以硬度低的材料代号表示。

For gate, globe, and check valves, as well as ball and butterfly valves, the sealing specific pressure qMF must be less than the sealing specific pressure q, and the sealing specific pressure is less than the sealing allowable specific pressure [q] (i.e., qMF < q < [q]).

通用阀门的壳体试验压力为材料在38℃时的额定工作压力的1.5倍。高压密封试验为材料在38℃时额定工作压力的1.1倍。低压密封试验各标准要求不同。

其中：

GB/T 13927-1992 、ISO 5208:2008、EN 12266.2-2012 为0.6MPa±0.01MPa；

GB/T 26481-2011、API 598-2009 为0.4MPa~0.7Mpa；

MSS SP61-2013 为0.56MPa；

API 6D-2014 为Ⅰ型：0.034MPa~0.1MPa、Ⅱ型：0.55MPa±0.69MPa；

ISO 14313:2007 为Ⅰ型：0.05MPa~0.1MPa、Ⅱ型：0.55MPa±0.07MPa；

API 6A（idt ISO  10423:2003） 为PSL3G：第一次：额定压力、第二次：2.0MPa±0.2MPa；PSL4：第一次：额定压力、第二次：2.0MPa±0.2MPa。

壳体试验、高压密封试验和高压上密封试验的具体试验压力见表1-1和表1-2。

Classification of valves by purpose or main structural features.

General classification method, that is, according to the principle, role and structure, is currently the most commonly used domestic and international classification method. Generally divided into: gate valves, globe valves, plug valves, ball valves, butterfly valves, diaphragm valves, check valves, throttle valves, safety valves, pressure reducing valves, steam traps, regulating valves.

阀门型号由阀门类型、驱动方式、连接形式、结构形式、密封面材料或衬里材料类型、压力代号或工作温度下的工作压力、阀体材料等代号组合而成。

阀门型号由7部分组成其含义如图所示。

NPS：

用于管道系统元件的字母和数字组合的尺寸标识，它由字母 NPS 和后跟的无量纲的整数数字组成。这个数字与端部连接件的孔径或外径等特征尺寸直接相关。无量纲数字可作为没有前缀 “NPS” 的阀门尺寸标识。无量纲的尺寸数字不代表测量值，也不能用于计算。

Class：

与阀门材料的力学性能和尺寸特性相关、用于有关阀门的压力/温度能力的字母和数字组合的标识。它由字母 Class 和后跟的无量纲整数组成。字母 Class 之后的数字不代表测量值，也不应用于计算。除非在有关标准中另有规定，管道元件许用压力取决于 Class 数值、材料以及允许工作温度。许用压力在相应标准的压力-温度额定值表中给出。

DN：

用于管道系统元件的字母和数字组合的尺寸标识。它由字母 DN 和后跟无因次的整数数字组成。这个数字与端部连接件的孔径或外径（用 mm 表示）等特征尺寸直接相关。

Notes:

1. 除在相关标准中另有规定，字母 DN 后面的数字不代表测量值，也不能用于计算目的。
2. 采用 DN 标识系统的那些标准，应给出 DN 与管道元件的尺寸的关系，例如 DN/OD 或 DN/ID。

PN:

A combination of letters and numbers used for reference purposes in connection with the mechanical and dimensional properties of piping system components. It consists of the letter PN followed by a non-factorized number.

Notes:

1. The numbers following the letter PN do not represent measured values and should not be used for calculation purposes, unless otherwise specified in the relevant standard.
2. The term PN has no meaning except in connection with the relevant pipe component standard.
3. The permissible pressure of piping elements depends on the PN value, material and design of the element as well as the permissible working temperature, etc. The permissible pressures are given in the pressure-temperature rating tables of the respective standards.
4. All piping components with the same PN and DN values and their mating flanges should have the same mating dimensions.

各工业企业中管道上普遍采用的阀门。

用来控制管道内介质流动的、具有可动机构的机械产品的总称。