Abstract: A plurality of spray nozzles are utilized to introduce a fluid into a vessel. Control valves are associated with each one of the plurality of spray nozzles. The control valves are either fully closed or fully open. The actual value of a process variable is compared to the desired value of the process variable to generate a difference signal. Control signals are generated in response to the difference signal. Different combinations of the control valves are opened in response to the control signals so as to provide a fluid flow rate which will maintain the actual value of the process variable substantially equal to the desired value. The on-off nature of the control valves provides a substantially maximum pressure drop across the spray nozzles when fluid is flowing through the spray nozzles.

Abstract: A brake control apparatus for railway cars having sprung and unsprung portions is interposed between a brake pressure supply line and a brake cylinder line. A first chamber is connected to the brake pressure supply line and a second chamber is connected to the brake cylinder line. The chambers are abutted by surfaces having different cross-sectional areas of a diaphragm which is biased. A first valve responsive to positioning of the diaphragm, and a second valve responsive to positioning of a strut in a strut cylinder, effect first and second predetermined relationships between pressure drop in the brake pressure supply line and pressure drop in the brake cylinder line. The strut cylinder, mounted between the sprung and unsprung portions of the railway car, may be adapted to sense partially loaded as well as fully loaded or unloaded conditions.

Abstract: A brake control apparatus for railway cars having sprung and unsprung portions is interposed between a brake pressure supply line and a brake cylinder line. A first chamber is connected to the brake pressure supply line and a second chamber is connected to the brake cylinder line. The chambers are abutted by surfaces having different cross-sectional areas of a diaphragm which is biased. A first valve responsive to positioning of the diaphragm, and a second valve responsive to positioning of a strut in a strut cylinder, effect first and second predetermined relationships between pressure drop in the brake pressure supply line and pressure drop in the brake cylinder line. The strut cylinder, mounted between the sprung and unsprung portions of the railway car, may be adapted to sense partially loaded as well as fully loaded or unloaded conditions.

Abstract: A flow rate meter is provided for measuring the flow rate of particulate material being conveyed in a fluid stream along a tubular member. The apparatus includes a throat portion in the tubular member which has a length sufficient to accomplish a pressure drop adequate for accurate particulate material flow rate measurement in the conveying of particulate material in a fluid stream through the throat. The pressure drop is measured across the throat and the measured pressure drop is correlated with the particulate material flow rate. There can be provided converging and diverging tubular sections on opposite sides of the throat to form a venturi. One or more of the flow rate meters can be used in the control of a particulate material blending system. A fluid flow rate measuring means can be used in conjunction with the flow rate meter to provide a signal representative of the difference between the flow rate of particulate material and fluid and the flow rate of the fluid alone, i.e.

Abstract: In a system and apparatus for railway car brake control, a brake control apparatus for cars having sprung and unsprung portions is interposed between a train brake valve in a brake pressure supply line and a brake cylinder line of each railway car. A supply chamber is connected to the brake pressure supply line and a control chamber is connected to the brake cylinder line. The chambers are abutted by surfaces of a spring biased diaphragm having different cross-sectional areas. A first valve is responsive to positioning of the diaphragm, which is also selectively fluid biased by a strut cylinder mounted between the sprung and unsprung portions of the railway car, to effect predetermined relationships between pressure drop in the brake pressure supply line and pressure drop in the brake cylinder line. When the particular car is loaded, the brake cylinder line experiences a pressure drop substantially equal to that effected in the brake pressure supply line by the train brake valve.

Abstract: A brake control apparatus for railway cars having sprung and unsprung portions is interposed between a brake pressure supply line and a brake cylinder line. A first chamber is connected to the brake pressure supply line and a second chamber is connected to the brake cylinder line. The chambers are abutted by surfaces having different cross sectional areas of a diaphragm which is biased. A first valve responsive to positioning of the diaphragm, and a second valve responsive to positioning of a strut in a strut cylinder, effect first and second predetermined relationships between pressure drop in the brake pressure supply line and pressure drop in the brake cylinder line. The strut cylinder, mounted between the sprung and unsprung portions of the railway car, may be adapted to sense partially loaded as well as fully loaded or unloaded conditions.

Abstract: In a method and apparatus for railway car brake control, a brake control apparatus for cars having sprung and unsprung portions is interposed between a brake valve in a brake pressure supply line and a brake cylinder line. A first chamber is connected to the brake pressure supply line and a second chamber is connected to the brake cylinder line. The chambers are abutted by surfaces having different cross-sectional areas of a diaphragm which is biased. A first valve is responsive to positioning of the diaphragm, which is fluidly biased by a strut cylinder mounted between sprung and unsprung portions of the railway car, to effect predetermined relationships between pressure drop in the brake pressure supply line and pressure drop in the brake cylinder line. The strut cylinder can be adapted to sense partially loaded as well as fully loaded or empty car conditions.

Abstract: Iron containing aqueous, acidic solutions, such as acidic stripping solutions used to remove iron from organic extractants, are purified by subjecting the acidic solution to a hydrothermal treatment at elevated temperatures and pressures which cause the precipitation of the dissolved iron in easily separable form. The hydrothermal treatment is accomplished at temperatures in excess of about 100.degree. C. The process can be applied to acidic solutions containing the dissolved iron in the form of ferric sulfate, ferric nitrate or chloride and is particularly adaptable to acidic stripping solutions resulting from the purification of organic extractants employed to extract iron impurities from solutions obtained in the acid leaching of clays, ores and concentrates.

Abstract: Aluminum-manganese alloys containing up to about 10.0% by weight manganese are made by reacting molten aluminum with a manganese oxide, such as MnO or MnO.sub.2, under a blanket of fluoridic salts, for example cryolite. The alloy can also be prepared by electrolyzing the oxides of aluminum and manganese in a fluoridic bath using aluminum metal as cathode.