CJ/T 25-2018 in English

Hand flow adjusting valves for heating

1 Scope

This standard specifies the classification and designation, working conditions and working pressure difference, valve body structure and size, materials, requirements, test methods, inspection rules, cleaning and treatment, marking, packaging, transportation and storage of hand flow adjusting valves for hot water system and air-conditioning water system.

This standard is applicable to the hand flow adjusting valves for heating with design pressure less than or equal to 2.5 Mpa, design hot water medium temperature less than or equal to 200°C and nominal diameter of 15 mm to 600 mm (hereinafter referred to as "adjusting valves").

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 1176 Casting copper and copper alloys
GB/T 1220 Stainless steel bars
GB/T 1348 Spheroidal graphite iron castings
GB/T 1414 General purpose metric screw threads - The plan for pipe systems
GB/T 5796.1 Trapezoidal screw threads - Part 1: Profiles
GB/T 5796.2 Trapezoidal screw threads - Part 2: General plan
GB/T 5796.3 Trapezoidal screw threads - Part 3: Basic dimensions
GB/T 5796.4 Trapezoidal screw threads - Part 4:Tolerances
GB/T 9113 Integral steel pipe flanges
GB/T 9439 Grey iron castings
GB/T 12229 General purpose industrial valve - Specification of spheroidal graphite iron castings
GB/T 13927 Industrial valves - Pressure testing
GB/T 17241.6 Integral cast iron flanges
JC/T 1019 Asbestos sealing packing

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply.

3.1
maximum stroke
displacement of the adjusting valve clack from the closed position to the fully open position

3.2
relative stroke
ratio of actual stroke to maximum stroke of adjusting valve stem

3.3
flow capacity
flow through the adjusting valves when the valve is in a fully open state, with a pressure difference of 100 kPa at both ends and a fluid density of 1,000 kg/cm3

3.4
valve authority
percentage of the pressure loss of the valve in the total pressure loss of the adjusting pipeline (including the valve itself) when the adjusting valve is fully open

3.5
ratio flow
ratio of the flow at a certain relative stroke of the adjusting valve to the flow when the adjusting valve is fully opened

3.6
regulating characteristics
functional relationship between ratio flow and relative stroke of adjusting valve When the valve authority is 100%, the regulating characteristics of the adjusting valve are called theoretical regulating characteristics; when the valve authority is less than 100%, it is called the actual regulating characteristic.

Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Classification and designation
5 Working conditions and working pressure difference
6 Structure and dimension of valve body
7 Materials
8 Requirements
9 Test method
10 Inspection rules
11 Cleaning and treatment
12 Marking, packaging, transportation and storage
Annex A (Normative) Test apparatus