GB/T 22481-2008Cereals, oilseeds and pulses -- Measurement of unit pressure loss in one-dimensional air flow through bulk grain (English PDF)

Foreword

This standard is equivalent to ISO 4174 Implementation.1998 "cereals, oilseeds and pulses unidirectional flow through bulk grain loss measuring unit pressure" (English Chinese Version).

This standard is equivalent translation ISO 4174:1998.

For ease of use, the standard ISO 4174:1998 made the following editorial changes.

a) "this International Standard" be replaced by "this standard";

b) use a decimal point instead of a decimal comma ",". ",";

c) Remove international standards preface, introduction;

d) with the GB/T 5518 "Inspection of grain and grain and oilseeds - Determination of relative density" instead of the original reference standard ISO 3507. 1976 "secret Meter. " Appendix A of this standard is an informative annex.

The standard proposed by the National Food Authority.

This standard by the National Standardization Technical Committee OILS.

This standard was drafted. National Food Authority Standard Quality Center, Henan University of Technology.

1 Scope

This standard specifies the method for determination of unidirectional airflow through the grain bulk of unit pressure loss, which can be used to calculate the total pressure loss in the ventilation unit.

Which is equivalent to the sum of the following several pressure loss.

a) in the ventilation system (ventilation pipes, etc.);

b) in the grain (the main content of this standard);

c) from the pipe into the channel at the grain heap.

This standard applies to the determination of the pressure loss of the gas flow rate in the following range of ventilation systems. If the flow rate does not exceed the following limits Speed, pressure loss in the ventilation system and airflow from the vent pipe into the grain heap passage pressure loss, the pressure loss with respect to grain heap Purposes, is negligible.

--- Main ventilation duct velocity 8m/s ~ 10m/s;

--- Sub ventilation duct velocity 4m/s ~ 5m/s;

--- Into the grain bulk velocity 0.25m/s.

This standard does not apply to the ventilation system airflow velocity greater than the speed limit above (eg. main pipe flow velocity reaches 30m/s), the case to calculate the pressure loss due to lower airflow distribution and discharge system caused.

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard.

GB/T 5518 Inspection of grain and grain and oilseeds relative density measurement Principle 3 Function with the speed airflow into the grain mass per unit length of time to express generated when a uniform airflow through the grain mass (m) of the pressure loss. by Test to determine the curve, and then come airflow through the grain bulk formula unit pressure loss.

4 Instrument