in the project of oil drilling, we need to use several types of flexible hose. usually, it connect between two steel pipe. since these two parts are moved in working.
like rotary drilling hose connect drilling pipe and kelly. so someone call it kelly hose. as photo below
usually, it need API 7K certificated, according to the working pressure, According to the working pressure, can be divided into A to E grade. working as below
| ID(inches) | OD(inches) | MBR(inches) | Straight Ends (inches) | Grade | Working Pressure (PSI) | Test Pressure (PSI) | Weight (lbs/ft) | Coupling Weight (lbs) | |
| Armored | Unarmored | ||||||||
| 2 | 4.6 | 36 | 36 | C | 4,000 | 8,000 | 20 | 16 | 65 |
| 4.6 | 36 | 40 | D | 5,000 | 10,000 | 20 | 16 | 65 | |
| 4.8 | 36 | 42 | E | 7,500 | 15,000 | 22 | 19 | 75 | |
| 2-1/2 | 4.8 | 36 | 36 | C | 4,000 | 8,000 | 23 | 18 | 67 |
| 4.8 | 36 | 40 | D | 5,000 | 10,000 | 23 | 18 | 67 | |
| 4.9 | 36 | 42 | E | 7,500 | 15,000 | 24 | 19 | 77 | |
| 3 | 5.7 | 36 | 36 | C | 4,000 | 8,000 | 25 | 20 | 81 |
| 5.7 | 36 | 40 | D | 5,000 | 10,000 | 25 | 20 | 81 | |
| 6.4 | 36 | 42 | E | 7,500 | 15,000 | 36 | 31 | 136 | |
| 3-1/2 | 6.2 | 36 | 36 | C | 4,000 | 8,000 | 28 | 23 | 90 |
| 6.2 | 36 | 40 | D | 5,000 | 10,000 | 28 | 23 | 90 | |
| 6.9 | 36 | 42 | E | 7,500 | 15,000 | 41 | 35 | 105 | |
| 4 | 6.7 | 36 | 36 | C | 4,000 | 8,000 | 33 | 28 | 104 |
| 6.7 | 36 | 40 | D | 5,000 | 10,000 | 33 | 28 | 104 | |
| 7.4 | 36 | 42 | E | 7,500 | 15,000 | 49 | 42 | 117 | |
| 5 | 8.4 | 48 | 38 | C | 4,000 | 8,000 | 53 | 44 | 200 |
| 8.4 | 48 | 42 | D | 5,000 | 10,000 | 53 | 44 | 200 | |
| 8.9 | 48 | 44 | E | 7,500 | 15,000 | 71 | 62 | 240 | |
| 6 | 9.4 | 48 | 38 | C | 4,000 | 8,000 | 71 | 62 | 302 |
| 9.4 | 48 | 42 | D | 5,000 | 10,000 | 71 | 62 | 302 | |
| 9.9 | 48 | 44 | E | 7,500 | 15,000 | 92 | 83 | 324 |
i have ask our purchasing department, they told me that some of rotary drilling hose are from china. and quality is acceptable.