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GB/T 18688-2023Agricultural irrigation equipment - Pressure losses in irrigation valves - Test method (English PDF)

农业灌溉设备灌溉阀的压力损失试验方法

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Issued by

State Administration for Market Regulation, China National Standardization Administration

Level / Type

National · Recommended

Issue date

November 27, 2023

Implementation date

June 1, 2024

Scope

GB/T 18688-2023 is the English-translated version of 农业灌溉设备灌溉阀的压力损失试验方法.

GB/T 18688-2023 is a test method for measuring the pressure loss produced when water flows through agricultural irrigation valves under steady conditions. By running the test, the relationship between flow rate and pressure loss can be obtained for a given valve, which helps irrigation system designers compare different valve types.

The document also gives the processing of test data and the content of the test report. It applies only to manual valves with equal inlet and outlet nominal sizes, and it does not address the purpose, design or application of the product.

Terms defined include nominal size, volume flow rate, pressure loss, piping pressure loss and bench pressure loss. Issued on 27 November 2023 and applicable from 1 June 2024, it replaces GB/T 18688-2012.

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Document preview — GB/T 18688-2023

National Standard of the People's Republic of China

ICS: 65.060.35
Classification: B 91
Replacing: GB/T 18688-2012

Issued by: State Administration for Market Regulation, China National Standardization Administration

Foreword
1 Scope
2 Normative reference documents
3 Terms and definitions

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents" Drafting.

This document replaces GB/T 18688-2012 "Test Method for Pressure Loss of Irrigation Valve of Agricultural Irrigation Equipment" and is consistent with Compared with GB/T 18688-2012, in addition to structural adjustments and editorial changes, the main technical changes are as follows:

a) Changed the scope (see Chapter 1, Chapter 1 of the 2012 edition);

b) Changed the definition of pressure loss of the test bench (see 3.5, 2.5 of the 2012 edition);

c) The requirements for flow measuring instruments have been changed (see 4.2.3, 4.2.3 of the 2012 edition);

d) Changed the requirements for pressure measuring holes (see 4.2.5, 2012 version of 4.2.5);

e) The requirements for the allowable fluctuation value of the measured quantity have been changed (see 5.2.1, 5.2.1 of the 2012 version);

f) The test method of valves has been changed (see 5.4, 2012 version of 5.4).

This document is equivalent to ISO 9644:2018 "Pressure loss test method for irrigation valves of agricultural irrigation equipment".

1 Scope

This document applies only to manual valves.

This document specifies a test method for the determination of the pressure loss produced when water flows through agricultural irrigation valves (hereinafter referred to as valves) under steady conditions.

The range and accuracy of valve performance parameters presented will assist agricultural irrigation system designers in comparing the pressure losses of various types of valves.

Through the pressure loss test, the functional relationship between the flow rate of the valve and the pressure loss can be obtained.

This document also specifies the processing method of test data and the content of the test report.

This document does not cover the purpose, design and application of the product.

The test method described in this document is suitable for valves with equal inlet and outlet nominal dimensions.

2 Normative reference documents

This document has no normative references.

3 Terms and definitions

The following terms and definitions apply to this document.

3.1 Nominal size

Numerical designation used to indicate valve size.

3.2 Volume flow rate

flowflowrate The volume of water flowing through the valve per unit time.

3.3 Pressure loss

delta p The pressure difference produced when water flows through two specified points in a system or a certain part of the system.

3.4 Piping pressure loss

delta pp The pressure loss in the test pipeline between the two pressure measuring holes upstream and downstream of the tested valve does not include the pressure loss of the tested valve. (See 5.4.4)

3.5 Benchpressureloss

delta pb The head loss between the pressure measuring holes upstream and downstream of the measurement area, excluding the pressure loss of the valve under test.

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 13 pages — is available in the English PDF.

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