252 COALFIELDS AND COLLIK1UKS OF AUSTRALIA. 



revolutions per minute, and high pressure steam of 1401b. is 

 used. Marble switch boards, Fig. 159, are used for each unit. 

 Geipel rapidity type of steam trap for automatically re- 

 moving condensed water in the steam pipes is used with this 

 plant. These traps are suitable for both the highest and 

 lowest pressures, and can be adjusted to act for a wide range 

 of pressure. The valve is arranged in such a way that it is 

 held on its seat by stearn pressure, consequently a valve of a 

 much larger area can be used than if the valve closed against 

 steam pressure. The valve is of the- rotating type, and is 

 separate from the valve spindle, so is not held fast by the fric- 

 tion of the stuffing box. Being provided with vanes, it is 

 caused to rotate while discharging, and consequently to grind 

 itself in at each discharge so that the seat is kept in good 

 order. There is no dribbling, but as soon as the trap commences 

 to discharge, the valve is forced well open. A sharp blow 

 through then occurs, until all water is discharged, when the trap 



Fig. 160. The Geipel Kapidity Steam Trap. 



is suddenly shut. The trap consists of two tubes fixed at one 

 end but free to move at the other, where the valve is situated. 

 The upper or inlet tube is brass, while the lower or discharge 

 tube is of iron. In Fig. 160 the valve E is held normally on 

 a light spring G. When the trap is cold or full of water, the 

 valve is depressed from its seat by the valve spindle C, which 

 abuts against the end of the lever N. "When steam enters the 

 brass tube the latter expands and moves the valve casing 

 downwards. The steam pressure and light spring then close 

 and hold the valve tight until water has again entered the 

 brass tube and cooled it, upon which the brass tube contracts 

 and moves the valve casing upwards until the valve spindle C 

 impinges on the lever and forces the valve open. As soon as 

 the valve is open the rush of water, so to speak, forces or 

 wedges the valve downwards, thus making the large opening 

 which gives the rapid discharge. So rapid indeed is the dis- 



