OH6泵型

6.1.38 Adequate clearance shall be provided at all bolting locations to permit the use of socket or box wrenches.

所有存在螺栓的地方应该由足够的空间，以便使用扳手或者套筒扳手

6.1.39 Unless otherwise specified or agreed, studs shall be supplied on all main casing joints, and all other joints and connections shall be supplied with external hexagon-head bolting.

除非另有说明或者约定，壳体主分面的连接应该使用螺柱，其他接头和连接应该使用外部六角头螺栓。

解释：对于本条有些厂家是不执行的，对于垂直剖分的OH2泵体，壳体的主分面多使用螺钉连接。而对于水平剖分的BB3泵，主分面多使用螺柱。

external hexagon-head bolting如下图

6.1.40 Fasteners (excluding washers and headless set-screws) shall have the material grade and manufacturer s identification symbols applied to one end of studs 3/8 in. (10 mm) in diameter and larger and to the heads of bolts 1/4 in. (6 mm) in diameter and larger. If the available area is inadequate, the grade symbol may be marked on one end and the manufacturer s identification symbol marked on the other end. Studs shall be marked on the exposed end.

对于一头≥3/8英寸（10mm）的螺柱，和螺栓头≥1/4英寸（6mm）的紧固件（不包括垫片和无头螺钉），应该有材料等级和制造商的标识符号。如果空间受限，那么等级符号可以标记在一头，制造商标识符号标记在另一头。应该标在螺柱漏出的一端处。

NOTE A set-screw is a headless screw with a hexagonal socket in one end.

注：A set-screw是那种无头的螺钉，一端有一个六边形的槽

解释：A set-screw附图如下：

6.1.1 Pressure casing fasteners shall be not less than 0.5 in. (12 mm) diameter.

承压壳体的紧固件应该不小于0.5英寸（12mm）直径。

6.2 Pump Types

泵种类

6.2.1 The pump types listed in Table 3 have special design features that prevent them from fully complying with this standard. These pumps shall be offered only if specified by the purchaser and if the manufacturer has proven experience for the specific application. Table 3 lists the features requiring special consideration for  these pump types and gives in parentheses the relevant subsection(s) of this standard.

表3列出的泵类型，其设计特点具体特殊性，使得他们不完全满足本标准。如果制造商有特定场合的可证明业绩，那么在买方的要求下，可以使用这些泵。表 3 列出了这些类型泵需要特别考虑的地方，并在括号中给出了本标准的相关分节。

Table 3 Special Design Features  of Particular Pump Types

表3 特殊类型泵的特殊设计特点

6.2.2  If the pump is deemed by the purchaser to be a special-purpose pump, refer to Annex O for guidance.

如果泵被买方指定为特殊用途泵，参考附录O的指导。

6.3 Pressure Casings

承压壳体

6.3.1  The maximum discharge pressure shall be the highest of the maximum discharge pressures as calculated for all of the operating cases. The calculations shall be based on the maximum differential pressure that the pump is able to develop when operating with the furnished impeller(s) at the continuous speed and when pumping the relative density (specific gravity) from respective operating cases, plus the maximum suction pressure for respective operating cases. The pump vendor shall  calculate the maximum discharge pressure  for the pump and shall record that value.

最大排出压力应该是所有操作工况下，计算得到的最大出口压力的最高值。计算应基于泵在所提供的叶轮以连续转速运行时，以及在泵送介质在各种运行工况下的相对密度（比重）时所能产生的最大压差，加上各自运行情况下的最大吸入压力。泵供应商应计算泵的最大排出压力，并记录该值。

解释：这么拗口，就是所有可能工况下，泵的出口压力能够达到的最大值。

6.3.2 If specified, the maximum discharge pressure shall be increased by the additional differential pressure developed during one or more of the following operating circumstances:

如果要求，存在如下操作情况时，最大排出压力应该加上额外的压力差：

a) operation with temporary liquid of relative density higher than those specified in the liquid characteristics section of the pump data sheet (e.g. post-construction pipe cleaning liquid);

存在短时间泵送相对密度高于数据表中指定流体的相对密度的情况。比如泵送施工后用于管道清洗液的工况。

 解释：对于数据表中泵送密度很低的泵，比如轻烃泵，那泵在水联运时的泵出口压力会远远高于泵送轻烃时的出口压力，因此要考虑这种情况。

b) installation of an impeller of the maximum diameter and/or number of stages that the pump can accommodate;

安装最大直径的叶轮，或者增加泵叶轮的级数

解释：增大叶轮直径和叶轮级数都会增加出口压力。

c)  operation to trip or maximum speed of the driver.

运行到驱动器的最大转速，或者跳闸转速

NOTE The purchaser will assess the likelihood of the occurrence of Items a), b), and/or c) before specifying any of them. Momentary differential pressure excursions are sometimes considered covered by the hydrostatic test margin (see 8.3.2.2).

注：买方应该指定a，b和c工况时，应该评估他们发生的概率。有时候短暂的压差上升可能会在水压试验测试测裕量范围内。

6.3.3 The pressure casing shall be designed to

承压泵壳应该设计成：

a) operate without leakage or internal contact between rotating and stationary components while subject simultaneously to the MAWP (and maximum operating temperature) and the worst-case combination of twice the allowable nozzle loads of Table 5 applied through each nozzle;

在MAWP（和最大操作温度）以及每个管口两倍表格5的管口受力的最差组合，两个条件同时存在的情况下，泵运行时不应有泄露或者存在动静部件的接触的情况。

b) withstand the hydrostatic test (see 8.3.2).

可以承受水压试验（见8.3.2）

解释：水压试验时MAWP的1.5倍，同时应该根据泵送介质温度进行修正。后面试验章节会详细说到。

NOTE The twice-nozzle-load requirement is a pressure casing design criterion. Allowable nozzle  loads  for  piping  designers are the values given in Table 5, which, in addition to pressure casing design, include other factors that affect allowable nozzle loads, such as casing support and baseplate stiffness.

注：两倍管口受力是承压壳体的设计标准。给管道设计人员的允许管口受力见表5，除承压壳体设计外，还包括影响管口允许受力的其他因素，如壳体支撑和底座刚度。

解释：有些高温泵，很多设计方要求管口受力为表5中的3或者4倍，因为高温泵可能承受更多的热膨胀受力。

6.3.4 For pressure casing components, the tensile stress used in the design shall not exceed 0.25 times the minimum ultimate tensile strength or 0.67 times the minimum yield strength for that material, whichever is  lower, with MAWP across the full range of specified operating temperatures. For castings, the minimum  ultimate tensile strength and minimum yield strength for that material shall be multiplied by the appropriate casting factor, as shown in Table 4.

对于承压壳体部件，在MAWP压力和全部的指定操作温度范围下，设计的拉应力不应超过材料的0.25倍最小极限拉伸强度，或者0.67倍最小屈服强度，两者之中的取小值。对于铸件，材料的最小极限拉伸强度和最小屈服强度还应该乘以一个合适的铸件系数，如表4所示。

解释：因为铸件存在缺陷的可能性比较高，因此要求更为保守

Table 4     Casting Factors

表4—铸件系数

6.3.5 The vendor’ proposal shall state the source of the material properties from those listed in Table H.2 (i.e. ASTM, ISO, UNS, EN, JIS), as well as the casting factors applied. National material standards other than those listed in Table H.2 may be used with specific purchaser approval.

卖方应该在报价文件中，提供材料（参数来自表H.2（比如ASTM，ISO，UNS，EN，JIS）），以及所用的铸件系数。除了列在表H.2中的，其他国家的材料标准在买方明确批准下可以被使用。

解释：中国的泵多采用GB的材料名称。铸件系数如上表。厂家的泵壳铸件很多是不做射线，超声，磁粉等检验的，只是在水压试验时验证泵壳的完整性。

NOTE1 In general, the criteria in 6.3.3 result in deflection  (strain) being the determining  consideration in the design of pump casings with respect to pressure retention and nozzle loads. Ultimate tensile or yield strength is seldom the limiting factor.

注1：一般来说，根据 6.3.3 准则导致的变形（应变）是泵壳设计中，有关压力保持和管口受力的决定性考虑因素。极限拉伸强度或者屈服强度很少作为限制因素。

解释：这句话的意思是，形变往往是决定因素，即使没有达到0.25倍的极限拉伸强度或者0.67倍的屈服强度，但是可能因为6.3.3中的因素导致了形变。

NOTE 2 For bolting, the allowable tensile stress is used to determine the total bolting area based on hydrostatic load or gasket preload. It is recognized that to provide the initial load required to obtain a reliable bolted joint under cyclic loading,    it is necessary that the bolting be tightened to produce a tensile stress higher than the design tensile stress. Usual values  are in the range of 0.7 to 0.9 times yield.

注2：基于水压试验或者垫片预紧力条件下，螺栓的允许拉应力用来确定总的螺栓面积。我们都知道，要在循环载荷下提供可靠的螺栓连接所需的初始载荷，就很有必要拧紧螺栓以产生高于设计拉伸应力的拉伸应力。通常，数值是在0.7~0.9倍的屈服应力。

解释：螺栓相比泵壳，可能要承受更大上限的应力。

6.3.6 Except as noted in 6.3.8, the MAWP shall be at least the maximum discharge pressure (see 6.3.1 and 6.3.2) plus 10 % of the maximum differential pressure and shall not be less than:

除了6.3.8说明的外，MAWP应该至少是最大排出压力（见6.3.1和6.3.2）加上10%的最大压差，并且应该不少于：

解释：这一条很重要。

a)  for pump types BB1, VS1, VS2, VS3, VS4, VS5, VS6, and VS7: a pressure rating equal to that of an ASME B16.5, Class 150 steel flange of material grade corresponding to that of the pressure casing;

对于BB1，VS1，VS2，VS3，VS4，VS5，VS6和VS7来说，压力等级应该等于ASME B16.5中的class 150钢制法兰的等级，法兰材料对应泵壳材料。

解释：也就是说，BB1，VS1，VS2，VS3，VS4，VS5，VS6和VS7泵WAWP至少为150磅法兰可承受的压力。比如，150磅的碳钢法兰在常温下可承受2MPa，则BB1，VS1，VS2，VS3，VS4，VS5，VS6和VS7碳钢泵在泵送常温液体时的泵壳MAWP至少是2MPa

NOTE  For the purpose of this provision, ISO 7005-1 PN20 and EN 1759-1, Class 150 are equivalent to ASME B16.5, Class 150.

注：就本规定而言，ISO 7005-1 PN20和EN 1759-1 Class150与ASME B 16.5 class150是等效的。

b) for all other pump types: a gauge pressure rating equal to at least 600 psi (4 MPa; 40 bar) at 100 °F (38 °C).

对于其他泵型，在100°F (38 °C)的温度下，压力等级（表压）应该至少等于600PSI（4MPa；40bar）

解释：其他泵型的MAWP，至少为常温下可承受4MPa。

如果某些厂家提供的OH2泵型，但是其设计压力或者法兰等级为PN20的，则就违背了此条要求。

6.3.7  The pump-seal chamber and seal gland shall have a pressure-temperature rating at least equal to the MAWP and temperature of the pump casing to which it is attached, in accordance with API 682, Fourth Edition, Section 3.1.52.

根据API682第4版3.1.52节，密封腔和密封格兰的压力温度等级应该至少等于所连接泵壳的MAWP和温度。

解释：密封腔和密封格兰前面有过附图。密封腔的承压和耐受温度应该和泵壳保持一致。

6.3.8 If specified, pump types VS6, VS7, OH6, BB3, BB4, and BB5 may be designed for dual pressure ratings. The purchaser should consider installation of relief valves on the suction side of such installations. If specified, suction regions shall be designed for the same MAWP as the discharge section.

如果指定，VS6，VS7，OH6，BB3，BB4和BB5泵型可能设计成双压力等级的形式。买方应该考虑泵入口安全阀的安装。如果指定，泵的吸入区应该和排出区有一样的MAWP。

解释：VS6，VS7，OH6，BB3，BB4和BB5要么是双泵壳，要么是高扬程泵。本条的意思是，这些类型的泵可以将入口和出口设计成不同等级的。但是如果设计成不同等级的，则入口必须有安全阀，因为存在出口高压液体回串的可能，可能入口区域的低压设计承受不了高压的液体回流。实际上，为了安全简单，现在泵都要求出入口等压设计。

6.3.9 Unless otherwise specified, MAWP of pressure casings for HPRTs shall be at least equal to the maximum inlet pressure or the minimum MAWP values specified by 6.3.6, whichever is greater. If a relief valve is provided on the downstream piping before the first block valve, the MAWP of the low-pressure region of the casing shall be at least equal to the specified relief valve set point.

除非另有指定，液力透平的泵壳的MAWP应该至少等于最大入口压力，或6.3.6中要求的最小MAWP值，两者之间取大值。如果下游管道的第一道截止阀前设置了安全阀，那么泵壳低压区的MAWP应该至少等于安全阀的设定值。

解释：液力透平泵的入口为高压侧。现在设计中，液力透平的出入口也都是等压设计。

6.3.10 The pressure casing shall be designed with a corrosion allowance to meet the requirements of 6.1.1. Unless otherwise specified, the minimum corrosion allowance shall be 0.12 in. (3 mm).

承压壳体的设计应该考虑腐蚀余量的要求，满足6.1.1的要求。除非另有规定，最小腐蚀余量应该是 0.12 in. (3 mm)

NOTE The vendor is encouraged to propose alternative corrosion allowances for consideration if materials  of  construction with superior corrosion resistance are employed without affecting safety and reliability.

注：考虑到如果使用的制造材料超级耐腐蚀且不会影响安全性和可靠性的前提下，鼓励卖方提出腐蚀余量的替代方案。

解释：不锈钢及以上材料的腐蚀余量可以为0。

6.3.11 The inner casing of double-casing pumps shall be designed to withstand the maximum differential pressure or 50 psi (350 kPa, 3.5 bar), whichever is greater.

双壳体泵的内层壳体，应该设计成能承受最大压差或者50 psi (350 kPa, 3.5 bar)，两者取大值。

解释：这主要是对VS6，VS7，BB5这种双壳体泵要求的。如下图的BB5形式的泵，白色的内壳体只承受蓝色外壳体与叶轮之间的压差，而蓝色外壳承受的是全压。

6.3.12  Unless otherwise specified, pumps with radially split casings are required in services for any of the following operating conditions:

除非另外说明，存在下述的任一操作工况时，应该使用径向剖分的泵。

解释：径向剖分泵比轴向剖分泵的承压能力更强，泵壳剖分面的密封效果更好。

a)  pumping temperature of 400 °F (200 °C) or higher;

泵送温度大于等于400 °F (200 °C)

b)  liquids with a relative density of less than 0.7 at the specified pumping temperature;

在指定的泵送温度下，泵送液体的相对密度小于0.7

c)  liquids at a rated discharge gauge pressure above 1450 psi (10 MPa, 100 bar);

额定排出口的液体压力（表压）大于1450 psi (10 MPa, 100 bar)；

d)  liquid temperature transients greater than 100 °F (55 °C);

泵送液体温度的瞬变超过100 °F (55 °C)

e) liquid temperature transients that cause casing metal temperature change rates greater than 5 °F (3 °C)  per minute.

泵送液体的温度瞬变引起泵壳金属温度变化超过 5 °F (3 °C) 

NOTE 1 Axially split casings have been used successfully beyond the limits given above, particularly for pipeline  applications at higher pressure and with lower relative density (specific gravity). The success of such applications depends on the margin between design pressure and rated pressure, the manufacturer s experience with similar applications, the design and manufacture of the split joint, and the user s ability to correctly remake the split joint in the field. The purchaser usually considers these factors before specifying an axially split casing for conditions beyond the above limits.

注1：轴向剖分的泵在上述情况下也有成功的运行，尤其是在更高压力和更低的相对密度的管线工况。这些工况的成功运行，依赖于设计压力和额定压力之间的裕量、依赖于相似工况下制造商的经验、依赖于结合面的设计和制造，和依赖于用户在现场对结合面正确的重塑。在指定轴向剖分泵壳用于超出上述限制的工况之前，买方通常会考虑这些因素。

解释：pipeline工况是指的管线工况，尤其指的是长输管线工况，下同。

NOTE  2  Items  d)  and  e)  are  for  operating  cases  where  a pump  can be “shocked”  if pumping liquids with different temperatures. These temperature transients tend to occur during start-up for a pump that is not warmed-up or cooled down ahead of the introduction of process liquid. Item d) is addressing step-changes in pumped liquid temperature, and Item e) addresses a slower rate of change in temperature but still exceeds the casing material temperature change rate.

注2：d)项和e）项用于泵送不同温度液体的运行情况，可能会引起泵的“冲击”。这些温度瞬变往往发生在泵启动过程中，因为泵在引入工艺液体之前没有预热或冷却。d) 项针对的是泵送液体温度的阶跃变化，而 e) 项针对的是温度变化率较慢但仍超过外壳材料温度变化率的情况。

解释：d和e条是第12版标准中新增的条款。

6.3.13 Radially split casings shall have metal-to-metal fits, with confined controlled-compression gaskets,  such as an O-ring or a spiral-wound type. Gaskets other than spiral-wound may be proposed and furnished if proven suitable for service and approved by the purchaser. Radially split pressure casing joints and bolting shall be designed to seat a spiral-wound gasket (see 9.3.2.3 for VS type pumps).

径向剖分的壳体应采用金属对金属的配合，并配有受限受控的压缩垫圈，如 O 形环或缠绕垫。如果证明适合使用并经买方批准，可提供并使用缠绕垫以外的垫圈。径向剖分的承压泵壳结合面和螺柱连接应设计为缠绕垫形式（参见 9.3.2.3，VS 型泵）。

解释：如下图，大多采用缠绕垫形式。

NOTE Table H.1 shows only spiral-wound gaskets for casing joints.  Spiral-wound  gaskets  are  generally  preferred because they are perceived by users to have had better availability, are more conducive to material identification, have a broader chemical compatibility and temperature range, contact a wider sealing surface (are less susceptible to leakage because of sealing surface irregularities), and are easier to handle and store than O-rings. API 682 specifically requires O- ring gaskets on low-temperature [ 350 °F (175 °C)] pressure-seal gland plates.

注：表H.1展示了结合面的缠绕垫。通常推荐缠绕垫，因为用户认为它们的可用性更好，更有利于材料识别，具有更广泛的化学兼容性和温度范围，接触更宽的密封面（不易因密封面不规则而发生泄漏），并且比 O 形圈更易于处理和储存。API 682 明确要求在低温[350 °F (175 °C)]承压密封格兰板上使用 O 形圈垫片.

6.3.14 Centerline-supported pump casings shall be used for all horizontal pumps except as allowed in 9.2.1.2.

中心支撑的泵应该用于所有的水平泵，在9.2.1.2中列出的除外。

解释：本条也就规定了，虽然OH1泵列在了本标准中，但是不推荐使用，因为OH1泵是底脚安装的，不符合本条的要求。

9.2.1.2说明的是，在温度小于150℃的BB1，BB2，BB3，BB4和BB5泵可以是底脚安装的。

6.3.15   O-ring sealing surfaces, including all grooves and bores, shall have a maximum surface roughness average value, Ra, of 63 μin. (1.6 μm) for static O-rings and 32 μin. (0.8 μm) for the surface against which dynamic O-rings slide. Bores shall have a minimum 0.12 in. (3 mm) radius or a minimum 0.06 in. (1.5 mm) chamfered lead-in for static O-rings and a minimum 0.08 in. (2 mm) chamfered lead-in for dynamic O-rings. Chamfers shall have a maximum angle of 30°.

包括沟槽和孔在内，所有的O型圈密封处的最大表面平均粗糙度，对于静态O型圈Ra= 63 μin. (1.6 μm)，对于动态O型圈Ra= 32 μin. (0.8 μm)。 对于静态 O 形圈，孔的半径不得小于 0.12 英寸 （3 毫米）或倒角引脚不得小于 0.06 英寸 （1.5 毫米）；对于动态 O 形圈，倒角引脚不得小于 0.08 英寸 （2 毫米）。倒角的最大角度为 30°。

解释：倒角引脚（chamfered lead-in）如下图所示的倒角的长直角边，30°就是下图中的倒角。

6.3.16  Spiral-wound gasket sealing surfaces shall have a maximum surface roughness average value, Ra, of 250 μin (6.4 μm) and minimum surface roughness average value of 125 μin (3.2 μm).

缠绕垫的密封表面的最大表面平均粗糙度Ra250 μin (6.4 μm)，最小表面平均粗糙度Ra125 μin (3.2 μm).

解释：缠绕垫安装面粗糙度的要求比O型圈的要求低。

6.3.17 Jackscrews shall be provided to facilitate disassembly of the casing. One of the contacting faces shall be relieved (counter-bored or recessed) to prevent a leaking joint or an improper fit caused by marring of the face.

为了方便泵壳的拆卸，应该提供顶丝。其中一个接触面应去除凹槽（反向钻孔或凹槽），以防止连接处渗漏或因表面损伤造成配合不当。

解释：就是泵壳需要带顶丝，泵壳接合面应该钻孔或提供槽。Counterbore hole的示意图如下。

6.3.18 The use of threaded holes in pressure parts shall be minimized. To prevent leakage in pressure sections of casings, metal, equal in thickness to at least half the nominal bolt or stud diameter, plus the allowance for corrosion, shall be left around and below the bottom of drilled and threaded holes.

承压壳体应该尽量减少使用螺纹孔。应尽量减少承压部件上螺纹孔的使用。为防止壳体的承压部分泄漏，应在钻孔和螺纹孔的周围和底部留出足够金属，其厚度至少等于螺栓或螺柱公称直径的一半，再加上腐蚀预留量。

解释：就是螺纹孔的周围要有足够的厚度，才能保证结构的承压。如下图的红色直线的厚度应该不小于螺柱的直径的一半+腐蚀余量

6.3.19 Internal bolting shall be of a material fully resistant to corrosive attack by the pumped liquid.

内部螺栓的材料应能完全抵御泵送液体的腐蚀。

6.3.20  If the manufacture of cast pressure casing parts requires the use of openings for core support, core removal, or waterway inspection and cleaning, these openings shall be designed so they can be closed by welding, using an appropriate, qualified weld procedure, during the completion of casting manufacture.

如果在制造铸造承压壳体部件时需要使用开口来支撑芯子、取出芯子或进行流道检查和清理，则这些开口必须设计成，可以在完成铸件制造过程中使用适当、合格的焊接程序进行焊接封闭的形式。

解释：这是铸造过程中的专业术语，core support是一种用于支撑铸型内部的芯子的开口或者装置。芯子是一种用于形成铸件内部空腔或者复杂形状的模具，通常由砂或者金属制成。core support可以帮助固定芯子的位置，防止其在铸造过程中移动或者变形。core support也可以方便在铸造完成后移除芯子，或者检查和清洗铸件内部的水路。

6.3.21  If specified, the main casing joint studs and nuts shall be designed for the use of hydraulic bolt tensioning. Procedures and extent of special tooling provided by the vendor shall be agreed.

如果指定，主结合面的螺柱和螺母应该设计成使用液压拧紧的形式。应与供应商商定提供特殊工具的程序和范围

NOTE  Hydraulic bolt tensioning of casing bolt studs and nuts is generally applicable to specific pump types such as BB3 and BB5.

注：壳体螺栓螺柱和螺母的液压张紧一般适用于特定类型的泵，如 BB3 和 BB5。

解释：因为他们大多是高压的，BB3，BB5泵的中分面螺栓，推荐液压拧紧。

6.4 Nozzles and Pressure Casing Connections

管口和承压壳体连接

6.4.1 Casing Opening Sizes

壳体开孔尺寸

6.4.1.1 Openings for nozzles and other pressure casing connections