Blowing Concrete Into Place 



Dotted Square Is Position of Mixing 

 Box Above Concrete Mixer 



Air CyHndcr for 



Main HoistingMixing Sand and 



Water Box to Top of Smalt Gravel 



Tank Concrete Mixer Water Mixing 



Tank Box 



A Specially Constructed Steel Car Which Conveys Concrete at the Rate of Fifty Feet a Second 

 by Utilizing Compressed Air. The Car Propels Itself with the Aid of a Gasoline Equipment 



ANEW system for conveying con- 

 crete to the place where it is to be 

 used employs compressed air and 

 the concrete travels at the rate of fifty 

 feet a second. It is especially appli- 

 cable for lining tunnels with concrete. 

 The mixing may be done outside the 

 excavation and the concrete conveyed 

 by a pipe line to the point of use. Or, 

 to cite a recent instance on the line of 

 the Carolina, Clinchfield & Ohio Rail- 

 road, the mixing may be done on the 

 spot upon a movable car. 



It was desired to put the concrete 

 lining into Sandy Ridge tunnel near 

 Dante, Va., without shutting off the 

 railway traffir through it. The concrete 

 ret|uired amounted to some 50,000 or 

 60,000 cubic yards. A steel car was 

 specially constructed, and pro\ided with 

 a gasoline equipment by means of w-hich 

 it could be made to propel itself. Half 

 way between the ends is located the 

 mixing compartment — open on hotli 



sides of the car. At a higher level, 

 extending the whole length of the car, 

 are located the stone bin, the water 

 tank and the sand bin. The water is 

 immediately above the mixer compart- 

 ment. The tW'O end bins have inclined 

 bottoms sloping towards the mixing 

 chamber where they deliver the sand 

 and the stone by suitable chutes. The 

 gasoline engine is located at one end of 

 the car beneath the sloping bottom of 

 one of the bins. Beneath the sloping 

 bottom of the other bin is placed the 

 air receix'cr and the bags of cement. 

 When the supply of compressed air runs 

 low, a fresh supply ma\' be taken from 

 an air main running through the tunnel. 

 The mixing chamber contains two 

 principal pieces of apparatus. One is 

 the mixer itself, placed on one side of the 

 car. The other is the charging skip. 

 Its permanent place is on the other side 

 of the car between the two chutes. 

 When these chutes have delivered their 



411 



