CENTRAL SCIENTIFIC CO., CHICAGO, U. 8. A. 



91 



No. 1406 (3-A & 4- A). 



No. 1408. 



1406. BLOWER and VACUUM PUMPS, Crowell Type A. Adapted for all purposes requiring air under 

 pressure of from 1 to 10 Ibs. to the square inch and any degree of vacuum not exceeding 24 in. 

 The pressure is not dependent upon high speed or centrifugal force. There are no springs, 

 gears, valves or unbalanced parts. Satisfactory for furnishing vacuum or pressure throughout 

 the laboratory. Air receivers are usually not required, but are of advantage where a close 

 regulation of the pressure is desirable. (See No. 1410.) 



No. 



1-A 



20 



Cu. in. free air per revolution , 



Cu. ft. free air per min. at maximum 



speed 6.9 



R. p. m. at maximum speed , 600 



Approx. h. p. at 3 Ibs. pressure % 



Pulleys, in 4x1 



Net weight, Ibs 24 



Pipe size, inlet and outlet, in y 2 



Floor space, in 10x6^4 



Each, without air receiver $26.00 



2-A 



45 



13 



500 



% 



4x1% 

 34 



34.00 



3-A 



125 



25.3 

 350 



% 



6x2% 

 90 

 1 



22x14 

 53.00 



4-A 

 280 



5-A 

 460 



1408. 



BLOWER and VACUUM PUMPS. Crowell Type D. For pressures up to 25 Ibs. per square inch 

 and vacua from 29 to 30 in. of mercury. The system of lubrication is positive and auto- 

 matically controlled by the air pressure. The heads are provided with water jackets for cool- 

 ing. Construction throughout is heavier than Type A, adapting this type for heavier duty. 

 (For Air Receivers see No. 1410.) 



No. 



1-D 

 15 



Cu. in. free air per revolution 



Cu. ft. free air per minute at maximum 



speed 4.3 



R. p. m. at maximum speed 500 



Approx. h. p. at 15 Ib. pressure or 29 in. 



vacuum % 



Pulleys, in 6x2 



Approx. net weight, Ibs 70 



Pipe size, inlet and outlet, in % 



Floor space, in 13x18 



Each, without air receiver 75.00 



2-D 

 40 



9.2 

 400 



1 



8x2 

 115 



% 



14x22 

 88.00 



3-D 

 100 



17 

 300 



12x4 



250 



1 



19x34 

 118.00 



4-D 



280 



40.5 

 250 



4 



14x4 



425 



1% 



23x38 



198.00 



5-D 



400 



46 

 200 



5 



18x6 



580 



2 



26x44 

 225.00 



