4 LEAKAGE SPECIFICAITONS AND CLASSES
4.1The maximum allowable seat leakage as specified for each class shall not exceed the set leakage in Table 1 using the test procedure as defined in Section 5. For Classes II through VI , each and every valve shall be tested .
在表1中给出不同的泄漏等级的最大泄漏量，并按第五部分所要求的测试程序去测试。 要达到等级2到等级6中的任一等级，每一个阀都必须测试。 4.2 Leakage Classes
泄漏等级
4.2.1 Class I . A modification of any Class II ,III or IV valve where design intent is the same as the basic class , but by agreement between user and supplier , no test is required .
一级密封 是根据等级二，三，四 来设计制造的，但是供方和用户已达成协议不需要测试。 4.2.2 Class II . This class establishes the maximum permissible leakage generally associated with commercial double port , double seat control valves or balanced single port control valves with a piston ring seal and metal to metal seats . Use test procedure Type A.
二级密封 主要是针对 工业双通双座控制阀或平衡型单通控制阀 那些带有活塞O型圈密封和金属对金属阀座密封。 使用A 类测试程序。 4.2.3 Class III This class establishes the maximum permissible leakage generally associated with Class II (4.2.2) , but a higher degree of seat and seal tightness . Use test procedure Type A.
三级密封 主要是针对那些阀座和密封硬度更高的二级密封所规定的相关的阀。规定了最大允许的最大泄漏量。使用A 类测试程序。
4.2.4 Class IV This class establishes the maximum permissible leakage generally associated with commercial unbalanced single-port , single-seat control valves and balan
ced single-port control valves with extra tight piston rings or other sealing means and metal to metal seats. Use test procedure Type A .
四级密封 主要是针对工业非平衡单孔单座控制阀和平衡型单孔控制阀带有紧固型活塞式密封圈或其他密封形式和金属密封，规定了最大允许泄漏量。使用A 类测试程序。
4.2.5 Class V This class is usually specified for critical applications where the control valve may be required to be closed , without a blocking valve , for long period of time with high differential pressure across the seating surfaces . It requires special manufacturing assembly and testing techniques . This class is generally associated with metal seat unbalanced single-port , single seat control valves or balanced single port designs with exceptional seat and seal tightness . Use test procedure Type B using water at the maximum operating differential pressure.
五级密封 主要是针对那些临界设备，不带截止阀，而控制阀要长期关闭，并有高速介质流过阀座表面。此类阀要求特殊的加工安装和测试技术。相关的控制阀有非平衡型单孔单座控制阀或平衡型单孔设计阀并且阀座和密封需要额外的硬化处理。使用测试程序B 。 测试
介质为水，并且在最大的操作压差测试。
4.2.6 Class VI This class establishes the maximum permissible seat leakage generally associated with resilient seating control valves either unbalanced or balanced single port with O rings or similar gapless seals . Use test procedure Type C .
六级密封 此等级规定了非平衡型或平衡型单孔带O 形圈或相似无缝软阀座密封的控制阀的最大允许阀座泄漏量。 使用C类测试程序
Table 1 表一
|
Leakage Class Maximum Seat Leakage Test Procedure 泄漏等级 最大阀座泄漏量 测试程序 |
Class I 一级 See Paragraph 4.2.1 None |
（See 4.2.1） 见 4.2.1 部份 没有 |
Class II 二级 0.5% of rated valve capacity Type A |
（See 4.2.2 ） 0.5%的额定流量 ( See 5.1) |
Class III 三级 0.1% of rated valve capacity Type A |
（See 4.2.3 ） 0.1%的额定流量 ( See 5.1) |
Class IV 四级 0.01% of rated valve capacity Type A |
（See 4.2.4） 0.01%的额定流量 ( See 5.1) |
Class V 五级 5*10-4 ml per minute of water per mm Type B |
（See 4.2.5 ） of orifice diameter per bar differential ( See 5.2) |
5*10-4 毫升/分钟/mm/bar |
泄漏率 |
Class VI 六级 Leakage per Paragraph 5.3.4 as expressed Type C |
（See 4.2.6） in ml per minute versus port diameter ( See 5.3) 参照表2中的数据 |
|
5. TEST PRPCEDURES 测试程序
5.1 Test Procedure Type A 测试程序 A
5.1.1 Test medium shall be clean air or water at 10-52C (50-125F)
测试介质为10-52度干净的的空气或水。
5.1.2 Pressure of test medium shall be 3-4 bar (45-60psig ) or the maximum operating differential pressure whichever is less .
测试压力为3-4bar 或最大操作压差 ，两者取其小者。
5.1.3 Leakage flow and pressure data shall be accurate to ±10 percent of reading .
泄漏量读数和压力读数的误差范围应为 ±10 %。
5.1.4 The test fluid shall be applied to the normal or specified valve body inlet . The valve body outlet may be open to atmosphere or connected to a low headless measuring device .
测试介质作用在阀的进口。阀出口与大气相通或与一些低压的设备相连。
5.1.5 The actuator shall be adjusted to meet the operating conditions specified . The full normal closing thrust as applied by air pressure , a spring or other means shall then be applied . No allowance or adjustment shall be made to compensate for any increase in seat load obtained when the test differential is less than the maximum valve operating differential pressure .
执行器应当调整到规定的操作条件。通过气压，弹簧或其他方法提供使阀正常全关的推力，当测试压差小于阀的最大操作压差时，不允许通过调整来补偿阀座负载。
5.1.5 On valve body assemblies made of stock ,tested without the actuator , a test fixture should be utilized which applies a net seat load not exceeding the manufacturer’s normal expected load under maximum service conditions .
作为库存阀体组件，没有执行器情况下进行测试，使用测试架为阀座加载，但不应超出正常的最大负载。
5.1.7 On water test , care shall be taken to eliminate air pockets in the valve body and piping .
在进行水压测试时，应当注意排除阀体内和管道内的气泡。
5.1.8 The leakage rate thus obtained can then be compared to the calculated values for Classes II, III and IV . Table 1.
测试的得到的泄漏率，和表一中等级II，III and IV 的数据相比较，是否达到相应的泄漏等级要求。
5.2 Test Procedure Type B
测试程序 B
5.2.1 Test fluid shall be clean water at 10-52C( 50-125F)
使用干净的10-52度的水进行测试。
5.2.2 The water test differential pressure shall be the maximum service pressure drop across the valve plug, not exceeding the maximum operating pressure at room temperature as determined by ANSI B16.1, B16.5, or B16.34 , or some lesser pressure by individual agreement (7 bar (100psi) pressure drop minimum ). Pressure measurement accuracy is to be in accordance with Paragraph 5.1.3
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