HYDRAULIC HOSES
Nowadays almost all road-building, municipal and other Russian and foreign vehicles have hydraulic transmission. Hydraulic transmission break down rarely, but from time to time it is necessary to change the old details, including hydraulic hoses. We would like to tell about the possibility to replace the foreign hoses to Russian ones. Nowadays Russian specialists use foreign hydraulic transmission, but the European standards are not so much known. It is more convenient to use Russian hoses.
There are 2 types of hydraulic hoses used in industry: skive hoses and spiral hoses. Skive hoses are used in hydraulic transmissions with high pressure – till 25 megapascals and with small radius of flexure. Spiral hoses are used in hydraulic transmissions with the pressure of 30-40 megapascals and with constant cycle charge. The European standards for skive hoses are DIN EN 853 and DIN EN 857, and they are almost similar to Russian GOST 6286. These standards are for the hoses which work with hydraulic mineral oils, engine propellant with temperatures from -40 to +100 C, and also for water and oil emulsion with temperatures from -40 to +70 C. These requirements are convenient to Russian hydraulic hoses.
There are 4 types of hoses DIN EN 853: 1SN and 2ST – skive hoses 1SN and 2SN – the same construction, but thinner external rubber layer. This permits to armour the hoses without preparatory cleaning of external rubber layer. The essential difference between foreign and Russian hoses is DN, which is fixed in inches. It is not always the same as Russian. For instance, the diameter of foreign hose with DN12 is 12,7 mm, which is larger than Russian one. At the same time DN10 and DN12 are 9,5 mm and 19 mm and they can allow 11% less liquid than Russian ones.
Leak resistance pressure The testing of Russian hoses on leak resistance and rupture (megapascals): DN Max pressure Leak resistance pressure Rupture pressure 1ST and 1SN 2ST and 2SN 2 ST and 2SN 5 250 415 500 830 1000 1650 8 225 400 450 800 900 1600 215 350 430 700 850 1400 10 180 330 360 660 720 1320 12 160 275 320 550 640 1100 16 130 260 520 19 105 210 420 25 88 165 175 325 650 31 63 125 150 38 50 90 100 200 51 40 80 32
The marking of the hoses DIN EN 853 is the following: Producer Type Caliber (in inches) Standard Nominal diameter The last 2 figures of the producing year The pressure is not marked, it is determined in the schedule. There are 2 types of DIN EN 857 hoses: 1SC and 2SC. Their characteristics are the same as DIN EN 853, but the bend radius is 40% less. There are 4 types of spiral hoses DIN EN 856: Type 4SP – 4-spiral skive hoses for middle-level pressure - Type 4SH – 4-spiral skive hoses for high pressure
Leak resistance pressure, bar Type R12 – 4-spiral hose for long work with high temperature and middle-level pressure Type R13 – 6-spiral hose for the most hard and long work with very high pressure. Its production is limited. ND Max pressure Leak resistance pressure, bar Rupture pressure, bar 4SP 4SH R12 R13 16 350 - 276 700 552 1400 1104 19 420 345 840 690 1680 1380 25 280 380 560 760 1120 1520 31 210 325 207 650 414 1300 828 38 185 290 172 370 580 344 740 1160 688 51 165 250 330 500 660 1000
DIN EN 856 have min temperature -40C ND, mm Min bend radius, mm 4SP 4SH R12 R13 6 150 - 10 180 130 12 230 16 250 200 19 300 280 240 25 340 31 460 420 38 560 500 51 660 700 630 830 DIN EN 856 have min temperature -40C
The characteristics of type 4SP: Nominal inside diameter Rupture pressure, bar Pressure according GOST The number of cycles with Rmin GOST EN 856 10 1400 1780 340 1000000 12 1360 1660 16 300 800000 19 1200 250 25 1000 1120 The hydraulic hoses satisfy the requirements of the customers and can be used both in Russian and foreign machines. The quality and technical control is made during all periods of production. Then the hoses are tested on the testing stand.