120 



Popular Science Monthly 



How a Photograph Can Show the 

 Efficiency of a Pumping Machine 



ONE of the fin- 

 est demon- 

 strations of correct 

 mechanical princi- 

 ples in a machine 

 is given in the ac- 

 companying illus- 

 tration. Although 

 the pump and mo- 

 tor are on a pre- 

 carious mounting 

 of eight glass tum- 

 blers, and although 

 the outfit is pump- 

 ing away at full 

 speed, a photo- 

 graph of eight min- 

 utes exposure fail- 

 ed to detect the 

 slightest vibration. 

 To the experienced 

 engineer, one look 

 at the picture 

 would convince 

 him of the pump's 

 high efficiency. 



And that is what 

 the manufacturers wanted 

 to show. The pump, which 

 is non-pulsating, has been 

 designed on a new me- 

 chanical basis. High speed 

 pumps that are seen now- 

 adays are crank driven. A 

 crank drives the pump pis- 

 tons fast at the middle of 

 the stroke, and then slows 

 them down at the end. The 

 result is a violently pulsat- 

 ing stream, the reaction of 

 which, especially if the water 

 is pumped to any height, is 

 enough seriously to jar the 

 pump. 



As shown at the right, 

 it has two pistons in the 

 same cylinder, so recip- 

 rocated by cams on the 

 pump frame work that a 

 solid, uniform flow is pro- 

 duced. One piston sucks 

 and lifts the water at con- 

 stant speed during the larg- 

 est part of its pumping 



stroke. Over the remainder of its stroke, 

 the same piston gradually trails the load 

 off while the other piston is assuming it. 

 The combined flow 

 is thus always uni- 

 form and equal to 

 the rated amount. 



The continual 

 stopping and start- 

 ing of the column 

 of water, which 

 causes a great 

 waste of power 

 and which is hard 

 on the machinery, 

 is thus replaced 

 by a uniform 

 stream which 

 doesn't as much 

 as knock over the 

 lead pencil at the 

 top of the ma- 

 chine. Compared 

 with other pumps, 

 the one described 

 here is said to ef- 

 fect a saving of 

 The almost entire lack of vibration or jar eighty per cent of 

 is a good indication that this non-pulsating power and fuel, 

 pump has a wonderfully high efficiency 



There Has Been a Short- 



Rollers 

 opgratinq 

 top piston 



Couple- 



Piston — ^ 



Couple - 



Pl5ton- 



Filler 



. /t^Cams 



^Rollers 

 operating 

 lower piston 



Discharge 



»^i_51idmq 

 r valve 



I 



Slidinq 

 valve 



Water 

 -entrance 



The principal parts of 

 the pump and their 

 relation to one another 



age of Coal in Italy 

 Ever Since 1913 



TALY is so pressed for 

 coal that gas engineers 

 are compelled to employ 

 substitutes. Since the war 

 with Turkey, in 1913, there 

 has been a serious shortage 

 of fuel in the country. To- 

 day, coal costs seven times 

 as much as it did a few years 

 ago. Yet, strange to say, 

 the price of coke has not 

 risen in proportion to coal. 

 At the m.iddle of 1916, coke 

 was costing but two and a 

 half times as much as before 

 the war. Private gas works, 

 which have made pre-war 

 contracts with the muni- 

 cipal authorities, are in a 

 precarious condition and are 

 running at enorn^ous losses, 

 due to the exorbitant prices 

 they are obliged to pay. 



