Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full — Part 5: Cone meters
通过插入圆形横截面管道的压差测量流体流量全部第5部分:锥度计
发布日期:
2016-03-07
ISO 5167-5:20 16规定了锥形流量计的几何形状和使用方法(安装和操作条件),当锥形流量计插入充满的管道中以确定在管道中流动的流体的流速时。
由于未校准的锥形流量计的不确定度对于特定应用可能太高,因此根据条款7校准流量计可能被认为是必要的。
ISO 5167-5:20 16还提供了计算流速的背景信息,并与ISO 5167?中给出的要求一起适用。1.
ISO 5167-5:20 16仅适用于在整个测量部分流动保持亚音速且流体可被视为单相的锥形流量计。未经校准的锥形流量计只能在管道尺寸、粗糙度、β和雷诺数的规定范围内使用。ISO 5167的这一部分不适用于脉动流的测量。它不包括在尺寸小于50毫米或大于500毫米的管道中,或管道雷诺数低于8 × 104或大于1.2 × 107的管道中使用未经校准的锥形流量计。
锥形流量计是一种主要装置,由同心地固定在管道中心的锥形限制器组成,锥形限制器的前端位于上游。ISO 5167这一部分中定义的锥形流量计的设计在壁中具有一个或多个上游压力分接头,以及位于锥形的背面中的下游压力分接头,与差压变送器的连接是穿过锥形到支撑杆的孔,然后向上穿过支撑杆。
锥形计的替代设计是可用的;然而,在撰写本文时,没有足够的数据来充分表征这些设备,因此,应根据条款7对这些仪表进行校准。
ISO 5167-5:2016 specifies the geometry and method of use (installation and operating conditions) of cone meters when they are inserted in a conduit running full to determine the flow rate of the fluid flowing in the conduit.
As the uncertainty of an uncalibrated cone meter might be too high for a particular application, it might be deemed essential to calibrate the flow meter in accordance with Clause 7.
ISO 5167-5:2016 also provides background information for calculating the flow rate and is applicable in conjunction with the requirements given in ISO 5167?1.
ISO 5167-5:2016 is applicable only to cone meters in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. Uncalibrated cone meters can only be used within specified limits of pipe size, roughness, β, and Reynolds number. This part of ISO 5167 is not applicable to the measurement of pulsating flow. It does not cover the use of uncalibrated cone meters in pipes sized less than 50 mm or more than 500 mm, or where the pipe Reynolds numbers are below 8 × 104 or greater than 1,2 × 107.
A cone meter is a primary device which consists of a cone-shaped restriction held concentrically in the centre of the pipe with the nose of the cone upstream. The design of cone meter defined in this part of ISO 5167 has one or more upstream pressure tappings in the wall, and a downstream pressure tapping positioned in the back face of the cone with the connection to a differential pressure transmitter being a hole through the cone to the support bar, and then up through the support bar.
Alternative designs of cone meters are available; however, at the time of writing, there is insufficient data to fully characterize these devices, and therefore, these meters shall be calibrated in accordance with Clause 7.