On the Influence of the Dimensions of Reaction Type Valve upon the Rock Drill Preformance

Abstract

In this paper, the term “dimensions of valve” means the valve weight and clearance between valve and valve seat. Two kinds of valve, which were same in size and made of duralmin (light) and steel (heavy), were used for this experiment under changing the valve clearance. In this study, following results were obtained.
In the case of the light valve, valve starts more quickly, shifting time is shorter, cushioning in the back room of the cylinder happens more quickly, and then, number of blows is more many and air consumption is fewer than the case of heavy valve. Consequently, on the whole, thermal efficiency is higher in the light valve.
The blow energy of piston and thermal efficiency become to lower when the clearance is too large. Then, it is considerd most suitable that the valve clearance would be selected so as to the air inlet area at the valve clearance is nearly equal to the area of air port opened to the cylinder.