OPTIMIZATION OF THE DESIGN OF SUBSOILING AND PRESSURIZED FLUID INJECTION EQUIPMENT

There are two different design objectives for subsoilers with pressurized fluid injection, for use as pan-breakers or injectors respectively. A large soil failure is desirable when it is used as a pan-breaker and little soil failure is advantageous when it is used as an injector. This paper determines optimum shapes of pan-breaker and injector, where the draught can be reduced by injecting pressurized air (about 1·2 MPa at the air tank) from a nozzle port at the tip of the chisel. The results show that the optimum pan-breaker with fluid injection should have a rake angle of 45 to 60°, a chisel thickness of 50 × 50 mm, and a heel position at 100 mm. The optimum injector with fluid injection should have a rake angle of 90°, a shank thickness of less than 15 mm, a chisel length of 250 mm, a chisel thickness of 30 × 30 mm, and a heel position at 100 mm. © 1994 Silsoe Research Institute.