低温容器的低温减压压力附件第3部分:尺寸和容量的测定(ISO 21013-3:2016)

[中文适用范围]： ISO 21013 的这一部分提供了具体的计算方法，用于确定以下每种指定条件下所需的排放质量流量： ——具有未损坏绝缘系统（外夹套加绝缘材料）的真空绝热容器在正常真空下，外夹套在环境条件下温度，内容物在规定的释放压力下的温度； ——真空绝热容器，其绝热系统（外夹套加绝热材料）未损坏，处于正常真空状态，外夹套处于环境温度，内容器处于指定排气压力下的内容物温度，加压系统的压力调节器完全运行； ——真空绝热或非真空绝热容器，绝热系统完好，但真空绝热容器处于真空状态，外夹套处于环境温度，内部容器处于内容物温度和规定的排气压力下，或者真空绝热或非真空绝热容器真空绝热容器，其绝热系统完好或部分完好，但在真空损失的情况下，以及暴露在火下的真空绝热容器中，内容物温度在规定的排气压力下； ——含有在 1 bar 压力下饱和温度低于 75 K 的流体的真空绝热容器，绝热系统完好，但真空空间中因空气或氮气而失去真空； ——含有在 1 bar 压力下饱和温度低于 75 K 的流体的真空绝热容器，且绝热系统未损坏，但真空空间中的空气或氮气以及在火灾的影响下会失去真空； ——绝缘系统完全有缺陷且暴露在火中的容器。 当应用条件没有合适的计算方法时，必须使用基于丰富的理论物理知识的良好工程实践来确定要排放的质量流量。 附录 A 提供了低温恒温器泄压装置的建议。 [外文原描述]： ISO 21013-3:2016 provides separate calculation methods for determining the required mass flow to be relieved for each of the following specified conditions: - vacuum-insulated vessels with insulation system (outer jacket + insulating material) intact under normal vacuum, outer jacket at ambient temperature, inner vessel at temperature of the contents at the specified relieving pressure; - vacuum-insulated vessels with insulation system (outer jacket + insulating material) intact under normal vacuum, outer jacket at ambient temperature, inner vessel at temperature of the contents at the specified relieving pressure, pressure regulator of the pressure build-up system functioning at full potential; - vacuum or non-vacuum-insulated vessels with insulation system remaining in place, but with loss of vacuum in the case of vacuum-insulated vessels, outer jacket at ambient temperature, inner vessel at temperature of the contents at the specified relieving pressure or vacuum or non-vacuum-insulated vessels with insulation system remaining fully or partially in place, but with loss of vacuum in the case of vacuum-insulated vessels, fire engulfment, inner vessel at temperature of the contents at the specified relieving pressure; - vacuum-insulated vessels containing fluids with saturation temperature below 75 K at 1 bar with insulation system remaining in place, but with loss of vacuum with air or nitrogen in the vacuum space; - vacuum insulated vessels containing fluids with saturation temperature below 75 K at 1 bar with insulation system remaining in place, but with loss of vacuum with air or nitrogen in the vacuum space with fire engulfment; - vessels with insulation system totally lost and fire engulfment. Good engineering practice based on well-established theoretical physical science needs to be adopted to determine the required mass flow where an appropriate calculation method is not provided for an applicable condition. Recommendations for pressure relief devices for cryostats are given in Annex A.