Chapter 14. -PIPING, FITTINGS, AND VALVES 



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REGULAR STRAIGHT 



UNION C BRANCH 



UNION ELBOW 



UNION BULKHEAD 

 FITTING 



UNION RUN 



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Figure 14-1.— Unions. 



low points in the system or machinery to be 

 drained. Some types of steam traps that are 

 used in the Navy are described here. 



MECHANICAL STEAM TRAPS.-Mechanical 

 steam traps in common use include ball float 

 traps and bucket-type traps. 



A ball float steam trap is shown in figure 

 14-4. The valve of this trap is connected to the 

 float in such a way that the valve opens when 

 the float rises. When the trap is in operation, 

 the steam and any water that may be mixed 

 with it flows into the float chamber. As the 

 water level rises, it lifts the float and this 

 in turn lifts the valve plug and opens the valve. 

 The condensate drains out and the float moves 

 down to a lower position, closing the valve. 

 The condensate that passes out of the trap is 

 returned to the feed system. 



A bucket-type steam trap is shown in figure 

 14-5. As condensate enters the trap body, the 

 bucket floats. The valve is connected to the 

 bucket in such a way that the valve closes as the 



bucket rises. As condensate continues to flow into 

 the trap body, the valve remains closed until the 

 bucket is full. When the bucket is full, it sinks 

 and thus opens the valve. The valve remains 

 open until enough condensate has passed out to 

 allow the bucket to float, thus closing the valve. 



THERMOSTATIC STEAM TRAPS.- There 

 are several kinds of thermostatic steam traps 

 in use. In general, these traps are more com- 

 pact and have fewer moving parts than most 

 mechanical steam traps. 



A bellows-type thermostatic steam trap is 

 shown in figure 14-6. The operation of this 

 trap is controlled by the expansion of the vapor 

 of a volatile liquid which is enclosed in a bel- 

 lows-type element. Steam enters the trap body 

 and heats the volatile liquid in the sealed bel- 

 lows, thus causing expansion of the bellows. The 

 valve is attached to the bellows in such a way 

 that the valve closes when the bellows expands. 

 The valve remains closed, trapping steam in 

 the valve body. As the steam cools and condenses, 



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