. Tentative revised boiler safety orders. re boilers are connected to a commonsteam main, two stop valves, with an ample free-blow drain betweenthem, shall be placed in the steam connection between each boilerand the steam main. The discharge of this drain valve must bevisible to the operator while manipulating the valve. The stopvalves shall consist preferably of one automatic non-return valve 82- REPORT OF BOILER CODE COMMITTEE, (set next the boiler) and a second valve of the outside-screw andyoke type; or, two valves of the outside screw and yoke type maybe used. 304 When a stop
. Tentative revised boiler safety orders. re boilers are connected to a commonsteam main, two stop valves, with an ample free-blow drain betweenthem, shall be placed in the steam connection between each boilerand the steam main. The discharge of this drain valve must bevisible to the operator while manipulating the valve. The stopvalves shall consist preferably of one automatic non-return valve 82- REPORT OF BOILER CODE COMMITTEE, (set next the boiler) and a second valve of the outside-screw andyoke type; or, two valves of the outside screw and yoke type maybe used. 304 When a stop valve is so located that water can accumulate,ample drains shall be provided. 305 Steam Mains. Provisions shall be made for the expansionand contraction of steam mains connected to boilers, by providingsubstantial anchorage at suitable points, so that there shall be noundue strain transmitted to the boiler. Steam reservoirs shall beused on steam mains when heavy pulsations of the steam currentscause vibration of the boiler shell Fig. 22 Typical Boiler Bushings and Flange . 306 Each superheater shall be fitted with a drain. 307 Blow-off Piping. A surface blow-off shall not exceed 1^in. pipe size and the internal and external pipes, when used, shallform a continuous passage, but with clearance between their endsand arranged so that the removal of either will not disturb theother. A properly designed brass or steel bushing as shown inFig. 22, or a flanged connection, shall be used. 308 Each boiler shall have a bottom blow-off pipe, fitted witha valve or cock, in direct connection with the lowest water spacepracticable; the minimum size of pipe and fittings shall be 1 in. andthe maximum size shall be 2i/2 in. Globe valves shall not be usedon such connections. NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 83 309 A bottom blow-off cock shall have the plug held in place bya guard or gland. The end of the plug shall be distinctly markedin line with the passage. 310 The
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectsteambo, bookyear1919
