. American engineer and railroad journal . ative to the wear of seats andvalves per unit of distance indicated that a wear of from jo inch toIs inch per 100,000 miles might be expected with balancedvalves,with from two to three times as much for unbalanced valves, whilethe wear on the link motion varied in about the same proportion. The expressions in regard to piston valves were all favorablewith one exception, this being with a road with five compound lo-comotives with piston valves. ThediflFereut styles of balanced slide valves may be broughtdown, generally, to two types, viz: Those whose b
. American engineer and railroad journal . ative to the wear of seats andvalves per unit of distance indicated that a wear of from jo inch toIs inch per 100,000 miles might be expected with balancedvalves,with from two to three times as much for unbalanced valves, whilethe wear on the link motion varied in about the same proportion. The expressions in regard to piston valves were all favorablewith one exception, this being with a road with five compound lo-comotives with piston valves. ThediflFereut styles of balanced slide valves may be broughtdown, generally, to two types, viz: Those whose balanced area isenclosed by straight strips, and those who balanced area is enclosedby circles. It was decided that the Richardson and the American valvescould well be taken to represent the two types. One single-balanceand one double-balance American valve were tested at Purdue Uni-versity, and one Richardson valve—the strips were afterv\ard re-moved from this, the hole in crown plugged, and it was th( u usedas a plain unbalanced Plate 1--Section Through Dynamometer. To get comparative results, the valve seat on the cylinder wasfilled and scraped to a true surface before the commencement of thetest, and the different valves were put in the engine and worn downto a bearing. All tests were made on the right .*idR of the locomo-tive, and in the forward motion only. The valves used were allnew. In order to measure and record the force ncc-^ssary to move thevalves a dynamometer (see Plate 1) was connected by a hinged pipewith an ordinary indicator, the motion of the drum b^ing takenfrom the valve stem. While this dynamometer was rather a crudeaflfair and not one that the Committee would recommend for accu-rate work, on account of the viriable ifriction of the leathers and themethod of taking up the water used by the indicator, yet it was thebest that the Committee could obtain, and every effort was madeto secure results that could at least be comparable. The dyna-mometer a
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
