1.1 该方法涵盖了使用FT4粉末流变仪量化压降和推导粉末床相对于固结应力或表观气体速度或两者的透气性的设备和程序。 1.2 该试验过程中产生的参数最常用于协助粉末加工和运输操作的设计和操作。它们还可以提供不同粉末或同一粉末的不同批次的流动行为的相对分类或比较，这些粉末在其加工设备内受到相似的应力和流动状态。 1.3 本标准中所述的50 mm仪器可用于测量最大粒径为6 mm的粉末和其他散装固体的性能。对颗粒比例较小（6-10 mm）的粉末进行测试是可行的，但建议其代表的颗粒不超过5 % 具有正态（高斯）尺寸分布的样本中的总质量的百分比。 1.4 所有观测值和计算值应符合实践中制定的有效数字和四舍五入指南 D6026 . 1.4.1 本标准中用于规定如何收集/记录或计算数据的程序被视为行业标准。 此外，它们代表了通常应保留的有效数字。所使用的程序不考虑材料变化、获取数据的目的、特殊目的研究或用户目标的任何考虑因素；并且通常的做法是增加或减少报告数据的有效位数以与这些考虑相称。考虑工程设计分析方法中使用的有效数字超出了本标准的范围。 1.5 单位-- 以国际单位制表示的数值应视为标准。 本标准中不包括其他计量单位。以SI以外的单位报告试验结果不应被视为不符合本标准。 1.6 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 测试方法可用于评估以下内容: 5.1.1 粉末的分类或比较-- 两个测量的PD q 并且计算出的透气性可用于对粉末彼此进行分类。 5.1.2 敏感性分析-- 该测试可用于评估一系列粉末特性或环境参数或两者的相对影响，如（但不限于）湿度、颗粒尺寸和尺寸分布、颗粒形状和形状分布、水分含量和温度。 5.1.3 质量控制 该测试可用于评估PD q 以及原料、中间体或产品的透气性。 5.1.4 工艺设计和操作-- 所确定的参数可用于量化粉末在多种加工环境中的行为。粉末通过管道或斜槽从储存容器中持续排放的能力主要取决于其流动特性、与结构材料的相互作用以及设备的几何形状 ( 1和 2. ) 3. 然而，设计方法假设在储存粉末的顶部和底部之间存在气体交换，从而允许通过出口的一致流动。 气体渗透率是放电速率的控制因素 ( 1和 2. ) 具有低透气性的粉末可能表现出减少的或间歇/脉动的流动，或两者兼有，这是仅考虑剪切和动态流动特性无法预测的。这可能会导致空腔/袋子/容器的填充或排放不良，从而导致重量均匀性差或排放缓慢。此外，由于填充阶段后夹带的气体增加，压缩过程中释放气体的能力降低，透气性低的粉末在压片操作中可能更容易受到压缩性能的影响。 注1: 该测试方法产生的结果的质量取决于执行该测试的人员的能力以及所用设备和设施的适用性。符合实践标准的机构 D3740 通常被认为能够胜任和客观的测试/取样/检查等。提醒该测试方法的用户遵守实践 D3740 其本身不能保证可靠的结果。可靠的结果取决于许多因素；实践 D3740 提供了评估其中一些因素的方法。关于粉末取样的附加指南见参考 ( 3. ) . 实践 D3740 是为从事土壤和岩石测试和/或检查的机构开发的。因此，它并不完全适用于执行该测试方法的机构。然而，这种测试方法的用户应该认识到，实践的框架 D3740 适用于评估执行此做法的机构的质量。目前还没有已知的合格国家机构来检查执行该测试方法的机构。

1.1 This method covers the apparatus and procedures for quantifying the pressure drop and deriving the gas permeability of a powder bed with respect to consolidation stress or superficial gas velocity, or both, using the FT4 Powder Rheometer. 1.2 The parameters generated during this test are most commonly used to assist with the design and operation of powder processing and transport operations. They can also provide relative classification or comparison of the flow behavior of different powders, or different batches of the same powder, that are subjected to similar stress and flow regimes within their processing equipment. 1.3 The 50 mm apparatus described in this standard can be used to measure the properties of powders and other bulk solids with a maximum particle size of 6 mm. It is practicable to test powders that have a small proportion of particles of 6-10 mm, but it is recommended they represent no more than 5 % of the total mass in samples with a normal (Gaussian) size distribution. 1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 . 1.4.1 The procedures used to specify how data are collected/recorded or calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user's objectives; and it is common practice to increase or decrease significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design. 1.5 Units— The values stated in SI units are to be regarded as standard. No other units of measure are included in this standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 The test method can be used to evaluate the following: 5.1.1 Classification or Comparison of Powders— Both the measured PD q and calculated gas permeability can be used to classify powders relative to each other. 5.1.2 Sensitivity Analysis— The test can be used to evaluate the relative effects of a range of powder properties or environmental parameters, or both, such as (but not limited to) humidity, particle size and size distribution, particle shape and shape distribution, moisture content and temperature. 5.1.3 Quality Control— The test can be used to assess the PD q and gas permeability of a feedstock, intermediate or product against pre-determined acceptance criteria. 5.1.4 Process Design and Operation— The determined parameters can be used to quantify powder behavior in numerous processing environments. The ability of a powder to discharge consistently from a storage vessel, through pipes or down chutes is primarily dependent on its flow properties, interaction with the material of construction and the geometry of the equipment ( 1 and 2 ) 3 . However, design methodologies assume that there is a gas interchange between the top and bottom of the stored powder that allows consistent flow through the outlet. Gas permeability is a controlling factor in discharge rates ( 1 and 2 ) . Powders with low gas permeability may exhibit reduced or intermittent/pulsatile flow, or both, that cannot be predicted from only considering shear and dynamic flow properties. This could lead to poor filling or discharge of cavities/bags/vessels and thus result in poor weight uniformity or slow discharge. Furthermore, a powder with low gas permeability may be more likely to have compromised compression properties in tableting operations due to increased entrained gas after the filling stage and a reduced ability to release this gas during compression. Note 1: The quality of the result produced by this test method is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this test method are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors. Additional guidance on sampling of powders is given in Reference ( 3 ) . Practice D3740 was developed for agencies engaged in the testing and/or inspection of soil and rock. As such it is not totally applicable to agencies performing this test method. However, users of this test method should recognize that the framework of Practice D3740 is appropriate for evaluating the quality of an agency performing this practice. Currently there is no known qualifying national authority that inspects agencies that perform this test method.