| 摘要 |
FIELD: engines and pumps. ^ SUBSTANCE: invention relates to oil producing equipment, namely to hollow bucket rods. Hollow bucket rod can be jointed to coupling element and has thread on its end to engage with that of said coupling element. Note here that proposed rod features inner diametre D1 held over entire length of the rod, outer diametre D2 at the rod center and outer diametre D3 at rod end with length L1. Note here that D3 exceeds D2. Note here that rod both ends have outer tapered thread with length L2. Aforesaid coupling element represents a coupling with inner tapered thread and outer diametre d, d-to-D1 ratio varying from 2.0 to 3.0. ^ EFFECT: expanded operating performances, higher efficiency, possibility to use small-diametre tubing string. ^ 6 cl, 5 dwg, 2 tbl |
