Design of three-stage sealing structure and investigation of sealing performance for 7000 fracturing plunger pump

As a key component of the drilling mud pump, the plunger seal often has problems such as seal failure in reconstruction of low-permeability sandstone reservoirs and the development of unconventional reservoirs, which, in turn, leads to low efficiency of drilling mud pumps and even great potential safety hazard. Based on this, this paper designs a three-stage sealing device at the hydraulic head for the 7000 fracturing plunger pump, and analyzes the sealing performance of the system. The effects of different working loads of the hydraulic head and axial pre-tightening force on the contact force of the seal ring and the stress distribution in the seal ring are explored, and the sealing effect of the three-stage seal of the fracturing plunger pump is confirmed. The results show that the peak stress and the peak contact pressure of the three rubber rings increases with the increasing of the working load of the hydraulic head; the peak stress and the peak contact stress of the three rubber rings during the installation process increase with the increase of the installation pre-tightening force. But the equivalent stress peak and the contact stress peak are directly related the fluid load under the action of the working fluid load; the maximum contact force of the rubber during the sealing process of the system is greater than that of the system working medium under different working fluid pressures. With internal pressure, the three sealing rubber rings can play a sealing role to varying degrees in sequence, and increasing the total life of the sealing body.