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A new pneumatic concentric nebulizer for flame spectrochemical applications has been designed and evaluated. The construction and fundamental operational characteristics of two versions, fixed and adjustable uptake, are described. Analytical figures of merit including detection limits, characteristic concentrations, and precisions, obtained in conjunction with a conventional atomic absorption spectrophotometer, are presented. Improvements in sensitivity of approximately 40 to 50% are typical with no concurrent losses in precision. Performance characteristics of the adjustable uptake version with an organic solvent (methylisobutylketone) are also described.

This paper continues the investigation of journal lubrication reported to the Society under the same title in 1923 and 1924. Friction curves are here presented for central and offset partial bearings whose curvature radius exceeds that of the journal. The characteristics of fitted partial bearings are then studied, including their carrying capacities and friction.

The present paper continues the investigations of journal lubrication originally reported to the Society a year ago in a paper of the same title covering the case of a journal completely surrounded by its bearing. The case of a partial bearing is considered in the following paper. The method of analysis leads to the formation of charts for the study of partial-bearing design problems, and some typical examples are solved with the use of these charts.

The author brings together here for the first time important formulas and charts that have been offered by bearing analysts in this field during the past fifteen or twenty years. Some new material is added for completeness, and some references made to earlier fundamental work. Descriptive matter that accompanied the original publication of the charts and formulas has been eliminated as far as practicable. Improved charts derivable from earlier ones, and the rearrangement of others will, it is hoped, prove more useful to the designing engineer than the original publications. The net result is a concise summary of valuable information. In order that the reader at the beginning may have a fair idea of what is to be found and where in this paper, an explanation of the contents follows: The first section dealing with journal bearings begins with a concise illustrated description of their several kinds. The side-leakage chart is then explained because from its curves are obtained the correction factors that are necessary for the proper application of the subsequent material to the solving of journal-bearing problems. Optimum conditions for journal bearings of three classes are shown by charts, tables, and formulas. The titles, captions, and notes on these pages are intended to be sufficient explanation. General conditions for journal bearings of several classes are next shown by a series of charts which are accompanied by the necessary textual explanation. Thrust-bearing loading and friction data follow the charts for general conditions for journal bearings. They refer only to Kingsbury thrust bearings, which are made with freely pivoted shoes supporting a thrust collar having an unbroken flat surface. Data are given only for a single set of such surfaces having six pivoted shoes. The appendixes, of which there are five, contain descriptive matter, the reading of which will help the reader in understanding the first section of the paper. Appendix A contains the symbols and their explanation. Appendix B gives a number of examples together with their solutions, which explain applications of the charts. These are by no means exhaustive. Appendix C discusses viscous flow in general, the viscosity coefficient, the relation between viscosity and friction, and gives useful formulas for several kinds of viscous flow useful to those dealing with bearing problems. Conversion factors are given for several units of absolute viscosity. The symbols for these formulas differ in some respects from those in Appendix A. Appendix D contains an explanation of perfect lubrication as it occurs in bearings, and covers such headings as tapered oil film, side leakage, film thickness, viscosity change within film, the flat-wedge film, the curved-wedge film, optimum conditions, deviations from optimum. This is a valuable introduction to the charts in the body of this paper. Appendix E is a bibliography of the technical literature referred to in or forming parts of the paper.

This paper contains many design and operating data furnished by makers of hearings for the trade and for machinery of their own manufacture. The poll of such manufacturers is by no means comprehensive hut it includes several of the larger firms. The data are available for critical examination and study with relation to advanced theoretical analyses of bearing problems. Many of the data are tabulated and classified on charts, the most useful of which has as its coordinates the pressure and the velocity. Upon this chart are applied special scales showing some of Dr. Albert Kingsbury’s “Optimum Conditions for Journal Bearings.” Examples are given showing how these analytical laws can be useful in the solution of simple practical problems of bearing design. The selection of a lubricant of suitable viscosity is explained by means of a chart that may be entered with the calculated absolute-viscosity coefficient at operating temperature, and will yield the required commercial viscosity in Saybolt or Redwood seconds or Engler number, for a mineral oil of any base.

A new general program for experimental work and publications recently formulated by the Committee is outlined in this report, and is followed by a brief statement of results already accomplished. Particular attention has been given to the coordination of data obtained by various investigators on viscosity under high pressure, to the study of pressure distribution in the oil film as applied to both thrust bearings and journal bearings, and to the development of methods for measuring oiliness. From experiments on the flow of liquids through very fine glass and platinum capillaries, it appears that the ordinary laws of viscosity may safely be relied upon down to a film thickness at least as small as one-millionth of an inch. The report concludes with a brief review of recent European investigations.

This paper visualizes the characteristics of the oil film and the pressures within it for a journal completely surrounded by its bearing. The influences of clearance and viscosity upon the journal friction are quantitatively shown by means of a chart that can readily be used for designing bearings. Several interesting examples are solved by means of this chart. A few of the characteristics of the journal partially surrounded by the bearing are also shown by curves. The study of partial bearings is not yet completed.

This paper presents operating and experimental data which show the wide range of application of Kingsbury thrust bearings, and the author gives particulars of typical installations which have been in successful operation since 1911. Wide application of these bearings has been made to vertical and horizontal hydroelectric units, horizontal steam turbines, centrifugal pumps, and ship-propelling shafts. To determine some of the service conditions a series of slow-speed tests was recently made on a bearing carrying a load of 10,000 lb. The area of the supporting thrust-bearing segments was varied from 71.5 sq. in. to 10 sq. in. in order to test unit pressures ranging from 140 lb. to 1000 lb. per sq. in. The speed was varied from 0.1 r.p.m. to 16 r.p.m., long runs being made at the lowest speeds.

The classic theory of bearing lubrication propounded by Reynolds and extended by Sommerfeld has shown that when a journal runs in a full bearing with a complete film, the journal center will run opposite the center of the bearing when the journal load acts directly downward against the bearing. The classic theory has, the author believes, also shown that the journal will never rise higher than opposite the bearing center, if the bearing measures 180 deg. long and if the load line bisects that angle. Consequently the impression has gained ground that under no circumstances will the journal rise higher than the bearing center in any clearance bearing—if the classic theory is correct. The present investigation was therefore undertaken to find out whether that current impression was reasonable. A study of journal running positions was undertaken for clearance bearings whose resultant pressures do not bisect the bearing angle. The 120-deg. bearing was chosen for the present study because it approximates the bearings widely used in steam turbines. Other angular lengths will be studied later if the results of the present study indicate that an extension of the work is desirable, much of the preliminary work already having been done. The result of our analysis proves that the current impression is erroneous. The journal may run with its center higher than that of the bearing, if the load, speed, viscosity, clearance ratio, and α/β ratio are compatible therewith. This must be so if the classical theory is correct. The present analysis indicates that the load direction upon a partial bearing has an amazing influence upon the running position of the journal. It also indicates that no matter how high above the bearing center the journal may run at any finite speed, it will return to run concentric with the bearing at infinite speed. This study disclosed other interesting phenomena that are explained in the text. Side leakage was neglected. The viscosity was assumed constant. Influence of friction upon the direction of the resultant pressure was estimated. Consequently the present work is readily comparable with that of Reynolds, Sommerfeld, Harrison, and with previous work of the author.