Principles of naval engineering - Historic Naval Ships Association

'Chapter 14. -PIPING, FITTINGS, AND VALVESVAPORVOLATILE LIQUIDVOLATILE LIQUIDVALVEREPLACEABLEHERMETICALLYSEALED BELLOWS(a)TRAP COLD: VALVE OPEN(b) TRAP HOT; VALVE CLOSEDFigure 14-6.— Thermostatic steam trap.11.326XLOCK NUTCYLINDER STEMCONTROLORIFICETO HIGH PRESSURE_^ORAIN SYSTEMCONTROLORIFICESTRAINERFigure 14-7.— Impulse steam trap.38.126this principle is utilized, we will consider thearrangement of parts shown in figure 14-7 andsee what happens to the flow of condensate undervarious conditions.The only moving part in the steam trap isthe disk. This disk is rather unusual in design.Near the top of the disk there is a flange thatacts as a piston. As may be seen in figure 14-7,the working surface above the flange is largerthan the working surface below the flange; theimportance of having this larger effective areaabove the flange will presently become apparent.A control orifice runs through the disk fromtop to bottom, being considerably smaller at thetop than at the bottom. The bottom part of thedisk extends through and beyond the orifice inthe seat. The upper part of the disk (includingthe flange) is inside a cylinder. The cylinder369