PUMPING MACHINERY OF THK WATER AND SEWERAGE HOARD. LIX. 



(indicating) No. 1 is the card of No. 1 Worthington engine 

 at Crown Street, this No. 2, is that of the semi-rotative 

 Hathorn-Davey pump at Marrickville; this No. 3, belongs 

 to the Hathorn-Davey rotative triple expansion pump at 

 Spottiswoode, of which the steam consumption is disputed; 

 and this No. 4, is the card of the compound rotative engine, 

 surface condensing, at Ryde Pumping Station. Now a 

 diagram is a most misleading thing unless it is verified by 

 actual investigation of all the points which it displays. 

 Notwithstanding that this Worthington engine carries its 

 steam for four-tenths of its stroke, it is 10°/° more economical 

 than this Watt engine, which cuts off at less than one- 

 tenth of its stroke. The duty of this Worthington engine 

 is 86 millions calculated on a proper daily work basis ; the 

 duty of this Watt engine is not more than 63 millions. This 

 is the engine Mr. Smail spoke of as a "Watt " engine. You 

 would naturally suppose that the Worthington using more 

 steam would be less economical than this ; this however is 

 not so. While the Watt engine carries 100 pounds pressure 

 in the boiler and 97 pounds initial pressure in the cylinder, 

 the Worthington engine carries 100 pounds pressure in the 

 boiler, 97 in the engine room and only 66 pounds initial 

 pressure on card. The difference in the volume of steam 

 at a pressure of 97 pounds and at a pressure of 66 pounds 

 would explain the difference in the cards between these 

 two engines, taking into consideration the different circum- 

 stances surrounding each. In the case of the Worthington 

 engine above referred to, the steam was wire drawn, and 

 yet notwithstanding this, it carried a good deal of the 

 temperature due to the higher pressure and would carry 

 more had it quicker means of reaching its work instead of 

 having to traverse several pipes in a roundabout way, losing 

 heat and increasing condensation in the process. 



(A slide showing the non-rotative engine at Marrickville 

 Pumping Station was now introduced.) 



