BS EN ISO 6803:2015 pdf download – Rubber or plastics hoses and hose assemblies — Hydraulic- pressure impulse test without flexing
This International Standard describes hose impulse testing, without flexing, of rubber or plastics hydraulic hose assemblies at both high and low impulse pressures. The high-pressure testing is carried out at pressures greater than 3 MPa and the low-pressure testing at pressures from 1,5 MPa to 3 MPa. The test procedure is applicable to hydraulic hose assemblies that are subject to pulsating pressures in service which are included in the product requirements.
NOTE Impulse test procedures with flexing can be found in ISO 6802, Rubber and plastics hoses and hose assemblies with wire reinforcements — Hydraulic impulse test with flexing.
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.
ISO 3448, Industrial liquid lubricants — ISO viscosity classification
ISO 8330, Rubber and plastics hoses and hose assemblies — Vocabulary
ISO/TR 11340, Rubber and rubber products — Hydraulic hose assemblies — External leakage classification for hydraulic systems
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8330 apply.
4 Apparatus
4.1 Pressure-application apparatus, capable of applying an internal pulsating pressure to the test piece at a rate specified in Clause 8.2 using a hydraulic fluid circulating through the test hose, while the fluid is maintained at the required test temperature. Each pressure cycle shall be within the tolerances shown in Figure 2 (for high- pressure testing) or Figure 3 (for low-pressure testing). The nominal rate of pressure rise for high-pressure testing is given by Equation (1) in Figure 2. The rate of pressure rise for low-pressure testing shall be such that the pulse remains within the wave form envelope (see Figure 3). 4
.2 Graphical recorder, digital-storage facility or oscilloscope, capable of measuring the pressure cycle to ensure that the wave form is within the envelope shown in Figure 2 or Figure 3. The recorder shall have a natural frequency of more than 250 Hz and shall be critically damped to give a response which is flat to within 5 % at up to 0,6 times the natural frequency.
5 Test fluid Select a test fluid preferably with a kinematic viscosity from 32 mm 2 /s to 100 mm 2 /s at 40 °C (i.e. from grade ISO VG 32 to ISO VG 100 as specified in ISO 3448), and circulate it at a rate sufficient to maintain a uniform fluid temperature within the test pieces. Other fluids may be used as agreed upon between the customer and the manufacturer.
6 Test temperature
The test temperature is normally specified in the referring hose standard. When the test temperature is not defined in the hose standard, the following temperatures are the preferred temperatures:
85 °C, 100 °C, 120 °C, 125 °C, 135 °C, 150 °C
The test fluid shall be circulated through the test pieces at the specified or chosen temperature with a tolerance of ±3 °C. Cooling or heating of the test chamber shall not be permitted, except when referring standards require testing with synthetic-base fluids at a temperature higher than 150 °C. When such higher temperatures are required, the test fluid need not be circulated, provided both the fluid and the test pieces are externally heated in the test chamber at the specified temperature with a tolerance of ±5 °C.
7 Test pieces
7.1 Test pieces shall be complete hose assemblies with suitable end fittings attached. Unless otherwise specified, test four unaged hose assemblies with end fittings which have been attached for not more than 30 days. Where the referring standard requires, also test aged hose assemblies.
7.2 Calculate the necessary free length of the hose in the test piece as shown in Figure 1. For values of d less than 25,4 mm, use d = 25,4 mm for the +2d term in the expression for the hose free length, so that the hose between the fitting shell and the start of the bend radius is straight. The actual free hose length shall agree with the calculated free hose length to within 0 1 + % or 0 8 + mm , whichever is greater
r minimum bend radius
d hose outside diameter.BS EN ISO 6803 pdf download.