Hydraulic accumulator-based controllable pressure injection device and method

Abstract

A hydraulic accumulator-based controllable pressure injection device includes a pressure storage system, a pressure maintaining system, a sealing system, and an injection system. The pressure storage system includes a pressure cylinder front half portion, an annular piston and a middle connecting body. The pressure maintaining system includes an accumulator, a pressure cylinder rear half portion and a rear end cover. The sealing system includes a hydraulic propulsion cylinder, a propulsion piston, a front end cover, a sealing tube, a thickened end portion, and an expansion rubber tube. The injection system includes a hydraulic valve body and an injection gun tube. The hydraulic accumulator-based controllable pressure injection device quickly applies pressure to the bottom of a borehole in a hydraulic manner, so that rock experiences tensile failure, and the hard rock excavation efficiency is improved.

What is claimed is: 
     
         1 . A hydraulic accumulator-based controllable pressure injection device, comprising a pressure storage system, a pressure maintaining system, a sealing system, and an injection system, wherein
 the pressure storage system comprises a pressure cylinder front half portion, an annular piston and a middle connecting body, which are mounted on a same axis, the annular piston is located between a pressure cylinder and a hydraulic adjusting tube and dynamically sealed, the pressure cylinder front half portion is fixedly connected to an end portion of the middle connecting body, and a high pressure fluid inlet flow passage having both ends respectively communicating with an outside and an inner chamber of the pressure cylinder front half portion is provided in the middle connecting body;   the pressure maintaining system comprises an accumulator, a pressure cylinder rear half portion and a rear end cover, the pressure cylinder rear half portion and a rear end of the hydraulic adjusting tube are detachably connected to the rear end cover, respectively, and sealed, an outer end of the rear end cover is provided with the accumulator, and the accumulator is communicated to an inner chamber of the pressure cylinder rear half portion;   the sealing system comprises a hydraulic propulsion cylinder, a propulsion piston, a front end cover, a sealing tube, a thickened end portion, and an expansion rubber tube, the sealing tube sequentially penetrates through a plurality of axes of the front end cover and the propulsion piston, a rear end of the sealing tube and the propulsion piston are fixedly connected into a whole, the expansion rubber tube and a front end of the sealing tube are butted and coaxially connected, the sealing tube and the front end cover are dynamically sealed, the propulsion piston and the hydraulic propulsion cylinder are dynamically sealed, a front end of the hydraulic propulsion cylinder is detachably connected to a rear end of the front end cover and sealed, a rear end of the hydraulic propulsion cylinder is fixedly connected to the middle connecting body, and an oil inlet and outlet port having both ends respectively communicating with the outside and an inner chamber of the hydraulic propulsion cylinder is also provided in the middle connecting body; and   the injection system comprises a hydraulic valve body and an injection gun tube, the hydraulic valve body is coaxially mounted inside the hydraulic adjusting tube in the pressure storage system and the hydraulic valve body and the hydraulic adjusting tube are dynamically sealed at front ends, the injection gun tube is coaxially sleeved inside the sealing tube and penetrates through the propulsion piston, the thickened end portion is coaxially and detachably connected to a front end of the injection gun tube, a rear end of the injection gun tube is fixedly connected to the middle connecting body, and a front end of the hydraulic valve body has a cone area fitting a groove at the rear end of the injection gun tube.   
     
     
         2 . The hydraulic accumulator-based controllable pressure injection device according to  claim 1 , wherein the annular piston is dynamically sealed with the pressure cylinder and the hydraulic adjusting tube through a guide strip and a Glyd ring, respectively, so that the annular piston is slidable between the hydraulic adjusting tube and the pressure cylinder. 
     
     
         3 . The hydraulic accumulator-based controllable pressure injection device according to  claim 1 , wherein the pressure cylinder front half portion and the end portion of the middle connecting body are welded together, the pressure cylinder rear half portion and the rear end cover are connected by a plurality of threads, and a plurality of O rings are provided therebetween respectively for sealing. 
     
     
         4 . The hydraulic accumulator-based controllable pressure injection device according to  claim 1 , wherein a raised circular ring is provided on an end face of the middle connecting body facing the pressure cylinder, the raised circular ring being located in an inner chamber of the pressure cylinder. 
     
     
         5 . The hydraulic accumulator-based controllable pressure injection device according to  claim 1 , wherein the hydraulic propulsion cylinder is connected to the rear end of the front end cover by a plurality of threads, an O ring is provided therebetween to ensure sealing of a hydraulic oil, and a guide strip and a step seal are provided between the front end cover and the sealing tube to ensure sealing of the hydraulic oil. 
     
     
         6 . The hydraulic accumulator-based controllable pressure injection device according to  claim 1 , wherein the thickened end portion is connected to the injection gun tube by a plurality of threads, and the hydraulic valve body and the hydraulic adjusting tube are dynamically sealed through a guide sleeve and a Glyd ring. 
     
     
         7 . The hydraulic accumulator-based controllable pressure injection device according to  claim 1 , wherein the groove at the rear end of the injection gun tube and the cone area at the front end of the hydraulic valve body are both chamfers of 45 degrees, and the groove is a 1×1 mm chamfer, and the cone area is an 8×8 mm chamfer. 
     
     
         8 . The hydraulic accumulator-based controllable pressure injection device according to  claim 1 , wherein the rear end of the hydraulic propulsion cylinder is welded to the middle connecting body, and the rear end of the injection gun tube is fixed to the middle connecting body by welding. 
     
     
         9 . A hydraulic accumulator-based controllable pressure injection method, comprising the following steps:
 a, inserting an injection gun tube into a rock borehole, and pushing, by a propulsion piston, a sealing tube to push an expansion rubber tube to a thickened end portion such that an outer diameter of the injection gun tube is enlarged to fit an inner wall of the rock borehole to form a sealed space at a bottom of the rock borehole;   b, starting a hydraulic valve body to fit a groove at a rear end of the injection gun tube, and feeding a high pressure fluid medium via a high pressure fluid inlet flow passage to form a high pressure area in a front section of a pressure cylinder;   c, monitoring pressure changes of the pressure cylinder and an accumulator; and   d, after a pressure reaches a predetermined value, reducing the pressure in a hydraulic adjusting tube to 0 gradually, when a pressure generated by the high pressure area against a cone area at a front end of the hydraulic valve body is greater than an oil path pressure in the hydraulic adjusting tube at a rear end, allowing the hydraulic valve body to slide backwards to be separated from the groove at the rear end of the injection gun tube, and allowing the high pressure fluid medium to instantaneously surge into the sealed space at the bottom of the rock borehole under own pressure and a thrust of an annular piston, wherein the pressure generated is sufficient to cause a rock to break from an inside.   
     
     
         10 . The hydraulic accumulator-based controllable pressure injection method according to  claim 9 , wherein the high pressure fluid medium is a high pressure foam or a high pressure water. 
     
     
         11 . The hydraulic accumulator-based controllable pressure injection device according to  claim 3 , wherein the annular piston is dynamically sealed with the pressure cylinder and the hydraulic adjusting tube through a guide strip and a Glyd ring, respectively, so that the annular piston is slidable between the hydraulic adjusting tube and the pressure cylinder. 
     
     
         12 . The hydraulic accumulator-based controllable pressure injection device according to  claim 4 , wherein the annular piston is dynamically sealed with the pressure cylinder and the hydraulic adjusting tube through a guide strip and a Glyd ring, respectively, so that the annular piston is slidable between the hydraulic adjusting tube and the pressure cylinder. 
     
     
         13 . The hydraulic accumulator-based controllable pressure injection device according to  claim 5 , wherein the annular piston is dynamically sealed with the pressure cylinder and the hydraulic adjusting tube through a guide strip and a Glyd ring, respectively, so that the annular piston is slidable between the hydraulic adjusting tube and the pressure cylinder. 
     
     
         14 . The hydraulic accumulator-based controllable pressure injection device according to  claim 6 , wherein the annular piston is dynamically sealed with the pressure cylinder and the hydraulic adjusting tube through a guide strip and a Glyd ring, respectively, so that the annular piston is slidable between the hydraulic adjusting tube and the pressure cylinder. 
     
     
         15 . The hydraulic accumulator-based controllable pressure injection device according to  claim 7 , wherein the annular piston is dynamically sealed with the pressure cylinder and the hydraulic adjusting tube through a guide strip and a Glyd ring, respectively, so that the annular piston is slidable between the hydraulic adjusting tube and the pressure cylinder. 
     
     
         16 . The hydraulic accumulator-based controllable pressure injection device according to  claim 8 , wherein the annular piston is dynamically sealed with the pressure cylinder and the hydraulic adjusting tube through a guide strip and a Glyd ring, respectively, so that the annular piston is slidable between the hydraulic adjusting tube and the pressure cylinder.