CRITICAL
MONOGRAPH
REVIEWS
ON " F L O W M E T E R S "
BY P. P. K R E M L E V S K I I ,
MASHGIZ,
1963,
653
pp.
Translated from Izmeritel'naya Tekhnika, No. 3, pp. 56-57, March, 1964
Some of the most important branches of our national economy, including the chemical, oil, metallurgical and gas industries, use on a wide scale various methods and means for measuring the flow of liquids and gases. The precision and reliability of such measurements determine the accuracy in planning technological processes and the possibility of their automation. In view of this,the second edition of P. P. Kremlevskii's monograph, for measuring flow are described, is indeed timely.
in which all modem methods and devices
This edition of the monograph differs considerably from the first edition of 1955. It has been greatly expanded. The author examines in detail the theory of instruments and the essence of the physical processes taking place in them, and provides recommendations with respect to their computation and design. A review of instrument designs is made after a comparative analysis ot units and components. The chapter on flowmeters with a variable pressure difference has been supplemented by new types of instruments, including flowmeter tubes, segment diaphragms, devices with autocompensation for density variations in the medium, pressure devices, pressure amplifiers, et al. Measuring problems are examined, including those of two-phase media at supercritical pressure ratios at the input and output of a pipeline. Chapters IX and X on spring and compensated differential manometers, which have acquired wider application since the publication of the first edition, have been revised. Chapters XIII and XIV dealing with variable-level and streamlined flowmeters have been extended. The former discusses the set of criteria which determines unambiguously the discharge coefficient, and specifies more precisely the equation for computing profiles ,,f a weir. The latter describes flowmeters of the ball type, those with rotating blades or vanes, and those of the latest float-type. Chapters XI, XII, XV-XXII inclusive, and chapter X X I V have been rewritten. In the first of these chapters methods are examined for the automatic application of corrections for variations in the density of the medium, and in the second, problems related with the measurement of varying flows. The other chapters deal with flowmeters based on various principles of operation, most of which have been developed in the past ten years. Some of them, for instance, those of the tachometrie type, are fairly widely used; others are as yet in the experimental stage, but they all have future possibilities, since they provide solutions in the field of flow measurements. The latter include the measurement of the flow of pulps, abrasive and corrosive media, fused metals, et al., for which "classical ~ methods cannot be applied. The book contains much original material consisting of the creative research of its author. We should examine in this light the chapter on t h e measurement of variable flows and on the dynamic characteristics of flowmeters. The author has established a generalized criterion for the smooltaing out of pulsating flows, whose particular case consists of Hodgson's criterion. He provides design formulas for damping filters. The detailed analysis of processes occuring in constricting devices is of great interest. Much original material is contained in the chapters dealing with differ~ ential manometers. The author provides a new approach to certain theoretical problems relating to several new methods of measuring flows, such as the tachometric and calorimetric methods, the spark ionization method of the flow, et al. The classification of instruments provided in the book has been substantiated scientifically, and the terminology has been carefully worked out. The book is provided with a wide, carefully-selected bibliography arranged in chapters. This bibliography will be very useful for persons desiring to study in detail any particular problem.
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However, the monograph has certain shortcomings. Thus, not a l l the sections have been treated with the same completeness. The classical measuring methods have been described exhaustively, but this cannot be said about the new methods. There are other deficiencies, but they are all of a secondary nature and, therefore, it is not worth dwe!ling on them. The general conclusion is that the reviewed monograph reflects with adeqdate completeness the modern state of techniques for measuring flows, and the presentation is well-founded scientifically, systematic and clear. E. F. Dolinskii.
HORMUTH.
HARDNESS
TABLES,
LEIPZIG,
1963
Translated from I z m e r i t e l ' n a y a Tekhnika, No. 3, pp. 57-58, March, 1964
The book under review deals with the measurement of the hardness of metals. It is a valuable manual for persons engaged in p r a c t i c a l measurements o f hardness. The main part of the book consists of tables for finding Brinell, Rockwell and Vickers hardness numbers from the dimemions of deformations produced by an indentor. The Tables are compiled in such d e t a i l that they provide for m e most precise measurements hardness numbers without any additional computations. Brinell hardness (HB). computation Tables are provided for indentor balls of radii D = 10, 5, 2.5, 1.25 and 1 ram, loads of 30 D z, 10 D z, 5 D z, 2.5 D z, 1.25 D 2, and 0.5 D z for indentation diameters of 0.200 to %000 m m in steps of 0.001 m m . The most frequently encountered indentation diameters and their corresponding hardness numbers are given in heavy print. Vickers hardness (I-IV) computation Tables determined by the diagonal of the pyramid indentation are given for loads of 0.001 to 100 kg-wt for measuring hardness in the range of HV 1-9000. Hardness numbers are given for indentation diagonals of 0.001 to 1.36 mm, in steps of 0.0001 m m for loads of 0.001 to 1.000 kg-wt, and in steps of 0.001 m m for loads above 1.000 kg-wt. Thus, these Tables comprise all three ways of measuring hardness by indenting a diamond pyramid, n a m e l y : microhardnessP= 0.001 - 0.160 kg-wt, hardness at small loads P = 0.2 - 5.0 kg-wt, macrohardness P = 10 - 100 kg-wt. The Rockwell hardness Tables are provided for reference instruments with an optical reading of the depth. In o o m m e r c i a l instruments the reading is taken off a d i a l - t y p e indicator whose scale is calibrated in hardness numbers. Therefore, in this ease no Tables are required. The manual has two Tables, one of which is for an HRC scale (a diamond cone indentor) With a range of hardness numbers from 14 to 70, and the olher for an HRB scale (a steel b a l l indentor) with a range of hardness numbers from 35 to 110. All the Tables are printed in bold type. A notched index of Tables is provided for b a l l diameters (Brinell) and loads (Vickers), which makes the Tables very convenient to use. However, it is regrettable that there should be some (only a few) misprints in the headings of Tables. The Tables are preceded by a section containing useful information with reference to practical measurements of hardness and the maintenance of uniformity in this field o f measurements, The first three chapters of this section provide most important information on the three hardness measurement methods (Brinell, Rockwell, and Vickers). For each method the following data are provided: procedure for measuring
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