GB/T 22481-2008 in English

《GB/T 22481-2008谷物、油料和豆类 单向气流穿过散粮的单位压力损失测定》由TC270（全国粮油标准化技术委员会）归口，TC270SC1（全国粮油标准化技术委员会原粮及制品分会）执行，主管部门为国家粮食和物资储备局。
本标准规定了单向气流通过粮堆的单位压力损失的测定方法，它可以用来计算通风机组的总压损。即相当于以下几处压力损失之和：
a)在通风系统中（通风管道等）；
b)在粮食中（本标准的主要内容）；c)从管道进入粮堆的通道处。
本标准适用于气流速度在以下范围的通风系统中压力损失的测定。如果气流速度不超过以下限速，通风系统中的压力损失和气流从通风管道进入粮堆的通道中的压力损失，相对于粮堆中的压力损失而言，，可以忽略不计：
―――主通风管道中的速度8m/s~10m/s；
―――分通风管道中的速度4m/s~5m/s；
―――进入粮堆的速度0.25m/s。
本标准不适用于气流速度不大于以上限速的通风系统（如主管道中气流速度达到30m/s），该情况下要计算由于气流分配以及卸料系统所引起的压力损失。

Scope

This standard specifies the method for measuring the unit pressure loss of unidirectional airflow through the grain pile, which can be used to calculate the total pressure loss of the ventilation unit. That is to say, it is equivalent to the sum of the following pressure losses: a) in the ventilation system (ventilation pipes, etc.); b) in the grain (the main content of this standard); c) at the passageway from the pipe into the grain pile. This standard applies to the determination of pressure loss in ventilation systems with airflow velocities in the following ranges. The pressure loss in the ventilation system and the pressure loss in the passage of the air flow from the ventilation duct into the grain pile is negligible in relation to the pressure loss in the grain pile provided that the air velocity does not exceed the following limiting speed: - the main ventilation duct ——The speed in the ventilation duct is 4m/s~5m/s; ——The speed entering the grain pile is 0.25m/s. Ventilation system (such as: the air velocity in the main pipe reaches 30m/s), in this case, the pressure loss caused by air distribution and feeding system should be calculated.