The Locomotive . ders. Thereducing valve should be set from 5 to 10 pounds less than the safetyvalve. General use rarely exceeds 50 pounds for paper mill type of paper-making machine takes care of the pressure hazardby having a packed steam joint in the roll journal so adjusted by a 68 THE LOCO M O TIV E July, spring that when the pressure reaches a certain point the joint willleak. Regardless of this safeguard a reducing valve must be used. One of the problems encountered in the design of rolls or calendersis to remove the water formed by the steams condensation. Usuallythis is
The Locomotive . ders. Thereducing valve should be set from 5 to 10 pounds less than the safetyvalve. General use rarely exceeds 50 pounds for paper mill type of paper-making machine takes care of the pressure hazardby having a packed steam joint in the roll journal so adjusted by a 68 THE LOCO M O TIV E July, spring that when the pressure reaches a certain point the joint willleak. Regardless of this safeguard a reducing valve must be used. One of the problems encountered in the design of rolls or calendersis to remove the water formed by the steams condensation. Usuallythis is accomplished by a siphon leading to a steam-tight trap. Thelatter accumulates water until full. Then the weight of the water causesthe trap to tip and discharge its contents into a drain. Steam pressurewithin the roll forces the water out through the siphon and into thetrap. This voiding of water is very important in order to prevent waterhammer. At the end of a davs run there will be some water left in the Figure 2 This often leads to cracking of the casting unless the attendant under-stands the proper method of warming up the machine in the steam is turned into a cold roll, the water in the lower part actsas a perfect insulator, allowing that part of the roll to remain coolwhile the upper part is being raised to steam temperature. One manu-facturer classes this as among the most frequent causes of the crack-ing of such rolls. To avoid this, the machine should be turning overslowly before steam is admitted. In rubber mills in particular some machines are piped up so as toallow a quick reduction of temperature by the admission of cold course, this sets up serious strains in the roll and is a cause ofbreakage. Even while this article is being written, there comes to our deskreports of a steam mangle explosion in a laundry at Kokomo, Indiana,in which four young women were killed and six others were seriouslyinjured. According to newspaper accounts, no
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Keywords: ., bookauthorhartfordsteamboilerin, bookcentury1800, bookdecade1860
