chemical or process industries. Highly accurate because of its pre cision meter mechanism, it requires no pipes or mercury a n d totalizes directly. R a n g e of the 8 different line sizes is 20 to 2400 g.p.m. Prices available from manufacturer. Dept. I EC, B-I-F Industries, Provi dence 1, R. I. 1-6
You Get EXTRA S A V I N G S From This M e t h o d of Compressed Air After Cooling Cooling water savings and power sav ings quickly repay the cost of the Niagara Aero (air-cooled) After Cool er for compressed air or compressed gases. In addition its long life' and the labor-saving simplicity of its main tenance give you an extra profit in comparison with water-cooled surface contact methods. With the Niagara After Cooler the heat of compression is removed and dispersed into the atmosphere by the evaporation of a very small amount of water. The compressed air temper ature is always brought below that of
Proportional
the atmosphere surrounding your air lines, so that no further condensation can take place. Large users of compressed air for plant services or processes choose Niagara Aero After Coolers for their dependable durability. T h e y have been making good records of service for over 25 years. Write for Bulletin 130.
N I A G A R A BLOWER Dept.
EC-8,
Niagara
405
Controller
New T h e r m o Electric Propor tional Controller provides accurate, dependable, proportional off-on process control with almost imper ceptible cycling, a n d will not per mit process conditions to exceed preset limits. Used in conjunction with primary instruments, such as indicating recorders having trans mitting slidewires, this controller provides accurate control of practi cally any process. Temperature, pressure, p H chemical concentra-
COMPANY
Lexington Ave., New York 1 7 , Ν . Υ.
District Engineers in Principal Cities of U. S. and
Canada
Circle No. 40 οn Readers' Service Card
SAFE
AND
ECONOMICAL
KNOWLES
ELECTROLYTIC PLANT for the PRODUCTION OF HYDROGEN
99.5-0/0 PURE
Illustration shows plant recently installed In Spain and consists of 256 1 8 , 0 0 0 ampere cells producing 2 , 1 0 0 eu. meters per hour.
Knowles Electrolytic plant produces hydrogen of a constant high standard of purity, together with oxygen 99.8% pun?. The plant is uniquely simple and safe and requires no highly skilled labour. Plants of all sizes up to a single installation absorbing 25,000 k\V are in operation in all parts of the world. THE
INTERNATIONAL
SANDYCROFT U. S. A . Agents:
ELECTROLYTIC CHESTER
CO. LTD. ENGLAND
A I R PRODUCTS, INC., P. O . Box N o . 5 3 8 , Allentown, Pa. Circle No. 33 on Readers' Service Card
76 A
PLANT
INDUSTRIAL AND ENGINEERING CHEMISTRY
H O 43
tion, liquid level, etc., are included. O p e r a t i o n a n d adjustment are sim ple a n d easy. I n s t r u m e n t accuracy is V 4 % of controller span as re ferred to accuracy of primary instru ment. Proportional control can be established u p to 100% of full scale range. Adjustments are noncritical over a wide range of process variations. If inadvertently misset, oscillation of process conditions will not occur. Price available from manufacturer. Dept. IEC, Thermo Electric Co., Inc., Saddle Brook, N. J. 1-7
