This standard specifies the requirements for the hydraulic impulse test without flexure for rubber and plastic hydraulic hoses and hose assemblies. This standard applies to the hydraulic impulse test without flexure for high pressure hydraulic hoses and hose assemblies that are subjected to pulse pressure during use. This standard does not apply to impulse tests with flexure. GB/T 5568-1994 Hydraulic impulse test without flexure for rubber and plastic hoses and hose assemblies GB/T5568-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Rubber or plastic hoses and hose assemblies-Hydraulie ienpulse test without flexing
Rubber or plastles hoses and hose assemblies-Hydraulie ienpulse test without flexing GB/T 5568-94
Generation GR5568--85
This standard adopts the international standard ISO/DIS6803-1991 "Rubber or plastic hose and hose assembly impulse test".
1 Subject content and scope of application
This standard specifies the requirements for the hydraulic impulse test without flexing of rubber and plastic hydraulic hoses and hose assemblies. - Hydraulic without flexing
This standard applies to the impulse test without flexing of high-pressure hydraulic hoses and hose assemblies that are subjected to impulse pressure during use. This standard does not apply to impulse tests with flexion. Reference standards
GB262 Determination of aniline point of petroleum products
GB265 Determination of kinematic viscosity of petroleum products Calculation method of dynamic viscosity GB 443L-AN Total Loss System Oil
Determination of the Condensation Point of Petroleum Products
GB786 Graphic Symbols for Hydraulic and Pneumatic Applications
GB/T1690 Test Method for Liquid Resistance of Alkaline Rubber GB3536 Determination of Flash Point and Ignition Point of Petroleum Products (Cleveland Open Cup Method) 3 Test Specimens
3.1 The test specimen shall be a hose assembly equipped with a suitable pipe joint. 3.2 The bending degree and free length of the hose specimen (i.e. excluding the pipe joint) shall be in accordance with the following provisions: Nominal inner diameter of the hose, mm
Bending degree
Note: R——
is the minimum bending radius specified for the hose
-is the outer diameter of the hose, with a tolerance of ten
3.3 Free length measurement of the hose assembly specimen is shown in Figure 1: Approved by the State Technical Supervision Bureau on January 2, 1994 Free length L, mm
0. 5 yuan R+2d
Yuan R+2d
1994-10-01 implementation
GB/T 5568-94
R+ 0. 5d +%
Bend 90°
L*Yuan R+2d
2R+d*%
b..Bend 180°
+PS*G+?
Figure 1 Pulse test hose connection and free length measurement 3.4 Four hose assembly specimens of the same specification should be tested. 4 Test equipment
Impulse test bench
4.1 The typical hydraulic circuit of the test bench (GB 786) shall be as shown in Figure 2: GB/T5568-94
Electric pressure converter
·Electric
Figure 2 Typical pressure transition loop of hose test apparatus
Intermediate temperature converter
No oil heater
4.2 The test bench shall be able to apply an internal pulse pressure to the specimen at a rate between 0.5 and 1.0 Hz by circulating a hydraulic fluid through the specimen;
4.3 The test fluid of the test bench shall be maintained at the required test temperature. 4.4 Each pressure cycle shall be within the tolerance range shown in Figure 3.6%
Test force
Test pressure before ± 5%
(lobar)
tobar)
One impulse
Figure 3 Pressure pulse cycle
4.5 The pressure rise rate in the first part of the pressure pulse cycle shall be between 350 and 550 MPa/s (3500～5500 baz/s): Determined as shown in Figure 4,
(1obar)
GB/T 5568—94
The pressure rise rate is determined at this point
Figure 4. Determination of pressure rise rate in impulse test
Test pressure
4.6 In order to be able to check the pressure cycle against Figure 3, a suitable curve recorder is required. The recorder shall have a natural frequency greater than 250 Hz and be accurately controlled to obtain a frequency characteristic curve with a range of 0.05 to 0.6 times the natural frequency. 5 Test temperature
The test temperature should be one of the following temperatures -
(55, 85, 93, 100, 125, 135 or 150) ± 3℃ The test liquid should circulate through the test sample within the specified temperature range. Measure the temperature at the inlet and outlet of the test tube respectively, and take the average value as the test temperature. Any temperature measurement value shall not deviate from the test temperature ± 3 degrees. 6 Pulse test pressure
The pulse test pressure is selected according to the standard requirements of the hose product. 7 Test liquid
Carry out the test at (55, 85.93) ± 3℃, use N46 machine oil (formerly known as No. 30 engine oil) to carry out the test at (100, 125, 135 or 150) ± 3℃, and use No. 1 standard oil. Its performance indicators are shown in Table 1.
Aniline point, ℃
Kinematic viscosity, mm\/a
Flash point (open cup method),
Pouring point, ℃
Note: 1) Determined at 40℃
2) Determined at 100℃.
8 Test steps
GB/T 5568-94
Table 1 Performance requirements of test liquid
Oil type and standard number
N46(GB 443)
103±10
41.4~50. 6
No.1' standard oil(GR/T 1690)
124±1
20±12
Test method standard number
GB'262
GB3536
8.1 Install the sample on the test device as required in Figure 1, adjust the hose to the specified bending degree, without twisting, and exhaust the gas contained in it.
8.2 After the test liquid temperature reaches the test temperature, apply periodic pulse pressure (square quilt) according to the requirements of Figure 3, and continue the test according to the specified number of cycles, or until the assembly is damaged. 8.3 If the pulse test is stopped for more than 24 hours due to unavoidable reasons before the specified requirements are reached, when the test is restarted, slight leakage of fluid may occur at the joint of the hose and the pipe joint. If this phenomenon disappears automatically within 30 minutes, it will not be regarded as a test failure. If the failure occurs within 25 mm from the pipe joint, it should be regarded as a failure of the pipe joint and recorded. 9 Result Expression
9.1 Record the number of cycles when it is damaged. If no damage occurs, record the number of completed cycles. 9.2 The damage judgment standard is as follows:
When testing the hose assembly, the damage caused by the joint falling off or bursting within 25mm from the joint can only be regarded as the combined damage of the assembly and should be recorded truthfully in the test report. When testing the hose sample, damage within 25mm from the pipe joint, or within a distance equal to the outer diameter of the hose (whichever is greater) shall not be considered as sample damage, and the test shall be repeated. 10
Test report
The test report shall include the following contents:wwW.bzxz.Net
National Standard No.:
Complete description of the sample pipe or hose assembly, test temperature;
Test pressure,
Rate of pressure rise,
Test liquid:
Pulse frequency,
Degree of bending of the sample:
Number of cycles to failure of each sample, or the number of cycles completed; GB/T5568-94
Minimum, location and method of damage of each sample, or the condition of each sample after the test is completed; k. Test date.
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard was drafted by the National Technical Committee on Rubber and Rubber Products Standardization, Hose Sub-Technical Committee. This standard was drafted by the Shenyang Rubber Industrial Products Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Wang Baozhu, Yan Songfeng and Wang Weixiang.
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