. The Street railway journal . ged in sizes up to 3 ins., of special composition,giving great strength and resistance to wear. They are made•one standard only, for all pressures. Under actual test, thebodies of these valves are said to stand a pressure of 4000 square inch without breaking, are tight, with a water pres-sure of more than 1000 lbs. per square inch, and are guaran-teed for 500 lbs. steam pressure. That the valve seat may behard and durable, the body is made of a specially hard andtough mixture. The discs are of a composition which doesnot contain any zinc. The spindles are
. The Street railway journal . ged in sizes up to 3 ins., of special composition,giving great strength and resistance to wear. They are made•one standard only, for all pressures. Under actual test, thebodies of these valves are said to stand a pressure of 4000 square inch without breaking, are tight, with a water pres-sure of more than 1000 lbs. per square inch, and are guaran-teed for 500 lbs. steam pressure. That the valve seat may behard and durable, the body is made of a specially hard andtough mixture. The discs are of a composition which doesnot contain any zinc. The spindles are all made of Tobinbronze, as the manufacturers experience has demonstrated thata Tobin bronze spindle working in a special composition bon-net will not cut under the highest steam pressures. These valves are made after the same general design as theHancock main steam valves, used on locomotives for a numberof years, and found to give perfect satisfaction with the highsteam pressures carried. From the sketch shown herewith of. SECTION OF GLOBE VALVE -a i-in. globe valve, it will be seen that the area of the mostcontracted part of the valve is ample and of full size. Allvalves sent out have tee handles. The metal is distributed to give uniform strength through-out, and no areas have been reduced or contracted to reduceweight. Two collars are placed upon the stem to guide the discnut, thereby compelling the disc to always seat squarely and ab-solutely preventing the disc from cocking. The valve seat is flat,as that form has many advantages over any other used invalves of this character. The valve disc has a projection on itwhich serves two purposes; it acts as a guide when the seat isground, and the lip or projection on the disc prevents the cut-ting of the seat by the wire drawing of the steam when thevalve is cracked or slightly open. When the valve is slightly raised from its seat, with the lipentering slightly, it allows the escaping steam to clean the seat,so that when the
Size: 1266px × 1975px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
