| Because gas drilling technology has incomparable advantages in Mining and hard rock openings of oil fields and natural gas compared with conventional drilling fluid,pneumatic DTH hammer drilling technology is one of the most effective rock breaking methods to deal with hard and medium hard formation.Pneumatic down the hole hammer drilling is regarded as one of the symbols of modern drilling technology and measuring drilling technology because it can greatly improve the drilling efficiency,ensure the engineering quality,reduce the construction cost and have significant technical and economic benefits.This is paid highly attention by the drilling industry form home and abroad.At present,from the development trend of drilling tool industry at home and abroad,efficient,energy-saving and environmental protection products are the main theme of future development.The research and development of the center rod valve distribution DTH hammer not only meets the development conditions of the theme,but also can adapt to various engineering construction fields in China,and is also one of the main research and development topics in the future.The center rod valve distribution DTH impactor has few parts and high drilling efficiency,the noise occurs at the bottom of the blasthole,the adaptability to various hard rock and complex rock conditions,and a wide range of drilling diameter.First of all,this paper analyzes the structure and principle of the central rod valve distribution DTH hammer,introduces the drilling characteristics,application fields,development background and trend of the DTH hammer.Structural design about the central rod valve distribution DTH hammer was carried out through three-dimensional modeling.Then,the kinetic model of the DTH hammer was established based on gas state equation and energy equation,gas energy balance differential equation,etc,taking the piston as the research object and considering the form of motion under its conditions,using solid kinematics,dynamics,gas dynamics and other related theories,based on the analysis of the gas distribution process and motion mechanism of the center rod valve distribution DTH hammer.At last,a dynamics simulation calculation system for DTH was developed based on the piston dynamics model.By using this software,According to the structure of the DTH hammer,input or change the corresponding parameters,with the help of computer software calculation,the performance parameter results of the DTH hammer under certain working parameters can be output: piston actual stroke,impact energy,impact frequency,gas consumption,impact power,etc.And the movement process of the DTH hammer can be simulated and calculated,and the pressure curve,velocity trajectory,displacement trajectory curve and acceleration trajectory curve of the front and rear air chambers are drawn,through which the internal dynamic process of the hammer can be seen.According to the calculation results,the influence rules of the main structural parameters of the air hammer on the performance are found,such as the weight of the DTH hammer piston,the air source pressure,the diameter of the front end face of the piston air chamber,the air distribution stroke,the diameter of the air distribution rod and the width of the air inlet passage of the rear air chamber.At the same time,the water carrying capacity and the minimum gas injection rate of the DTH hammer in the working process are also studied,which provides some guidance for the practical work in the field.This article completed the dynamics simulation calculation system by established kinetics of the center rod valve distribution DTH hammer,the hammer can be designed and optimized,which greatly improve the efficiency of the design and optimization of the DTH hammer,the software interface is concise,simple to operate,easy to use,and very friendly to front-line designers,laying a good technical foundation for the structural design and optimization of our country's DTH hammers. |
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