Laminating Film Pet Pe,Aluminum Metallized Film,Bopp Laminating Film Cangzhou Yunfeng Packaging Products Co., Ltd. , https://www.yunfengpackaging.com
6.1.2 The outlet pressure measurement point should be located downstream of the test valve, at a distance of no less than 10 times the pipe diameter (10d) from the valve.
6.2 A temperature measurement point should be placed downstream of the outlet pressure measurement point, with a minimum distance of 5d between them.
6.3 The flow measurement point should be positioned downstream of the temperature measurement point, ensuring a minimum separation of 5d between the two.
6.4 The tubing used must be straight and free of bends, with consistent hole diameters along its axial direction to ensure accurate measurements.
6.5 The size of the tubing and related fittings must match the inlet and outlet port dimensions of the valve. The installation should be as horizontal as possible to minimize turbulence and maintain measurement accuracy.
6.6 Pressure Testing Holes
6.6.1 The diameter of the pressure testing hole must be between 1mm and 6mm.
6.6.2 The length of the pressure-measuring hole should be at least twice the diameter of the hole itself.
6.6.3 The centerline of the pressure measuring hole must be perpendicular to the centerline of the tubing. The intersection between the tubing wall and the hole should be sharp, without any burrs or rough edges.
6.6.4 The connection between the pressure measuring point and the instrument piping should have a minimum diameter of 3mm to ensure proper fluid flow and prevent blockage.
6.6.5 When connecting the pressure measurement point to the measuring instrument, all air trapped in the connecting line must be purged to avoid inaccurate readings.
7 Test Methods
7.1 Test Run
Under nominal pressure and rated flow conditions, the valve should undergo 20 consecutive switching operations to ensure it meets the requirements outlined in section 4.1.
7.2 Pressure Loss Test
7.2.1 Full Flow Range Pressure Loss Test
Adjust the test system to cover a flow range from zero to rated flow. At least four measurement points should be taken across this range to plot a curve showing flow versus pressure loss.
7.2.2 Pressure Loss Test at Rated Flow Rate
Measure the pressure loss from the inlet to the outlet, as well as from the inlet to the working port and from the working port to the outlet, at the rated flow rate.
Note: During the pressure loss test, the outlet pressure must remain above 0.1MPa.
7.3 Internal Leak Test
Set up the test system so that the inlet pressure reaches the nominal pressure. Depending on the spool valve function and structure, measure internal leakage from the working port and return port at any operating position. The internal leakage must meet the requirements specified in section 4.3.
Note:
â‘ During the internal leak test, the pressure on the outflow side should be atmospheric.
â‘¡ The pressure must be increased from atmospheric to the nominal pressure within 15 seconds.
7.4 Pressure Test
Block the oil ports and apply pressure to the valve at the actuated position. If the nominal pressure is ≤16MPa, apply 1.5 times the nominal pressure; if it is >16MPa, apply 1.25 times the nominal pressure. Maintain the pressure for 3 minutes and check for oil leaks. The outlet pressure during the test should be atmospheric. The test results must meet the requirements of section 4.4.
7.5 Durability Test
Perform 100,000 continuous switching operations on the sliding valve under nominal pressure and rated flow conditions. Evaluate the pressure loss and leakage performance after the test.
8 Inspection Rules
8.1 Type Test
8.1.1 A type test is a comprehensive evaluation of the valve’s quality and performance.
8.1.2 Type tests must be conducted under the following conditions:
a) For newly manufactured directional valves (including product conversions).
b) When design, process, or material changes affect the valve’s performance.
c) When a pilot valve has been produced and previous type tests showed non-conformities.
d) Every three years for batch-produced valves.
Test items include: commissioning test, full flow range pressure loss test, internal leakage test, pressure test, and durability test.
8.1.3 The number of samples for type testing shall be three. One sample will undergo a full test, while the others are tested for specific performance parameters. If any item fails, the sample size will be doubled for retesting. If the retest still fails, the type test is consideredä¸åˆæ ¼ (unqualified).
8.2 Factory Test
Factory tests must be completed before the product leaves the factory. The test items include: commissioning test, pressure loss test at rated flow, internal leakage test, and pressure test.
8.3 Decision Criteria
8.3.1 The factory test items for the pilot valve must be divided into sub-tests and full tests, following the sampling method outlined in GB/T 2828.
8.3.2 The ordering party reserves the right to re-test the reversing valve according to the factory test items and requirements. The re-sampling method follows GB/T 2828.
8.3.3 Special orders require joint development of test conditions and rules by the design, manufacturing, and demand-side parties.
9 Marking, Packaging, Transportation, and Storage
9.1 Identification
Each reversing valve must have a nameplate indicating the following:
a) Product name, model, and symbol.
b) Main technical specifications.
c) Manufacturer’s name.
d) Manufacturing date.
9.2 Packaging
The valve should be packaged using moisture-proof materials. The packaging box must be sturdy, with clear and neat markings on the outer surface, including:
a) Product name, type, and quantity.
b) Total mass and net weight in kg.
c) Manufacturer’s name, address, and destination station.
d) Packing date.
9.3 Transportation
During transport, the reversing valve must be handled gently, with a maximum stacking height of 1m. It must be protected from moisture and rain.
9.4 Storage
The valve should be stored in a dry, well-ventilated area, away from chemicals.
9.5 Accessories
The package should include the following:
a) Product certification.
b) User manual.
c) Spare seals and dust covers.
d) Packing list.
Additional Note: This standard was proposed by the State Bureau of Machinery Industry. It is managed by the National Automotive Standardization Technical Committee. The standard was drafted by Qingdao Special Purpose Vehicle Factory.