Report of Jubges ox Pumps, cOc. 95 



sure Avas increased in proportitm to tlic number of the blowers tlirotigh 

 whieli the air was obliged to pass. 



It was a matter of regret to the committee, that tlicir time proved 

 too limited for a test of the relative power reipiired under the ditfer- 

 ent conditions of work. With the ability thus to augment the 

 intensity of the l)last, by tlie attachment of nuu-e blowers, the inven- 

 tor secures the desideratum of a slow speed of the fans, and conse- 

 quently diminished wear of tlie parts. We earnestly reconunend 

 the a^vard to- Mr. Clark, of a tirst premium, for a "nuiltiplc fan 

 blower." 



Xo. 804. JRolai'i/ BIowc/'.—H. S. Townsend, Kew York city. 



"We were tlioroughly impressed with the peculiar excellence of 

 these machines. We consider them superior beyond comparison to 

 any fan blower extant, and to excel in economy and efficiency all 

 others of their own class. From the nature of the case, a fan blower 

 can produce onl}' a comparatively weak and inetlicient blast, which 

 has a strong tendency to succomb Avlieu determined resistance is 

 made to its progress. Consequently at the very moment a positive 

 and vigorous blast is required it is found that the momentum of the 

 air grows weaker and M'eaker, while the fan continues its revolution 

 without any efiective result, but at tlie same time it does not fail to 

 nvdko heavy and expensive draughts u])on the motive power. This 

 iuetliciency is specially observable in metallurgical operati(Uis, for 

 when the charge of the furnace is low, the tuyeres are very apt to 

 become clogged, and the greatest elfort of the blast is required to 

 kee}) them free, so that the melting may continue until all the metal 

 has been drawn off. The rotary lihjwer not only overcomes this 

 difficulty, but also effects a great saving in po\ver, and wear and tear 

 of the parts. Its superiority over others of its own class lies in tlie 

 feet that the impellers work in no other lulu'icator than that of the 

 surrouiuling air. The surface friction is consequently a minimum. 

 The duplex arrangement of the gearing and driving belts prevents 

 all unequal strain, and the system adopted by tlie makers in the fitting 

 up of the parts, insures great dural)ility in the structure. V>y com- 

 paring the rotary Idowcr witli blowing cylindi;rs. it will l)e i^vijn that 

 the comparatively high speed of the former (loo to oOO revolutions), 

 renders an equalizing receiver unnecessary, besides effecting in other 

 respects considerable economy in the first cost of the machineiy. The 

 hand blower for smithy purposes is exceedingly compact and admira- 

 bly adapted for the purpose for which it is intended. For the fore- 



