. Electric railway review . valve that admits water to the plunger,and a waste water line from this controlling valve to relievepressure on the ram. There are two general classes of regu-lators. One type causes the damper to be opened or closedcompletely when the pressure for which it is set is reached andto remain so until the other pressure is reached. Theother type is designed to open and close the damper gradually,the position of. the damper at all times corresponding withthe various pressures. Regulators of the latter class do notmaintain the steam at a definite pressure, but con
. Electric railway review . valve that admits water to the plunger,and a waste water line from this controlling valve to relievepressure on the ram. There are two general classes of regu-lators. One type causes the damper to be opened or closedcompletely when the pressure for which it is set is reached andto remain so until the other pressure is reached. Theother type is designed to open and close the damper gradually,the position of. the damper at all times corresponding withthe various pressures. Regulators of the latter class do notmaintain the steam at a definite pressure, but control the firepurely from a commercial standpoint. They obtain from thecoal the greatest possible number of heat units that are obtain-able by damper control. Figure 396 (V3-1) shows a regulatorof this type; the pressure from the steam line is connectedto the under side of the diaphragm and the pressure on dia-phragm is counterbalanced by a weight on a lever. Sometypes use a weight to load the lever, others use springs; that. Figure 396 (V3-1). shown is provided with both. Either one alone will not givethe desired adjustment for the regulator. It is generally found most economical to allow about fivepounds variation in pressure from the time the damper startsto move until it is full open or closed. When two springs areused the full range of pressure variation is adjustable as fol-lows: If the upper spring is loaded to 10 pounds in tensionand no load is put on the bottom spring, then the balancelever will move from one stop screw to the other with a veryslight added pressure. If top spring is loaded to 40 poundsand lower one to 30 |)Ounds, it will then require a very con-siderable pressure variation to carry the lever from one stopto the other. It will be noted that the pilot valve cylinder ismoved by the balance lever and the valve stem Is operated bythe tapered stem operating bar. which in turn is controlled bythe movement of the piston and the operating weight carriedon piston
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectstreetr, bookyear1906
