摘要:

In this paper consideration is given to the posssibility that the pre-treatment of coal with recovery of by-products may secure and economic advantage in the production of electricity in the United States of America.Reference is made to the trend of opinion in the minds of power station engineers and to the great interest which is maintained in the subject.The economic possibilities are reviewed and stress is laid on the necessity for securing a maximum revenue from the sale of such gas as is produced by the process of pre-treatment, and it is calimed that this result can be obtained only by co-operation with public service companies supplying gas to domestic and industrial concerns.The installation of the McEwen-Runger process at the Lakeside station of Milwaukee Electric Railway and Light Co. is described and an account is given of its development so far as it has been continued in America, the earlier experimental work which originated in England being omitted. Particulars are given of the progress which has been made, together with an indication of the direction which future development will follow.

DOI:10.1049/jiee-1.1930.0015

出版商:IEE    

年代:1930

数据来源: IET

摘要:

The paper deals with the economics of the production of power and valuable by-products from brown coal, which is very plentiful in Germany but has an extremely low calorific value.

DOI:10.1049/jiee-1.1930.0016

出版商:IEE    

年代:1930

数据来源: IET

摘要:

The paper opens with the statement that Great Britain is dependent almost entirely upon coal for the production of electricity, the amount of water-power available being comparatively small. This being so, the inauguration of the “grid” transmission system and the co-ordination of power production afford favourable conditions for combining the latter with the distillation of coal.The development of the Babcock process of low-temperature coal distillation is briefly described. So far as the authors are aware, this is the only process of its kind developed in Great Britain. It is suggested that the electric power plant of the future will take in coal as its raw material, but will deliver, in addition to electricity, motor spirit, fuel oil, creosote, pitch and other derivatives of coal tar. A discussion of the actual results obtained from the coal distillation plant at Dunston-on-Tyne follows.The plant was designed for the production of an ideal power-station fuel, low in volatiles and therefore smokeless, and for the recovery of the more valuable by-products consistent with the production of such a fuel. The broad result obtained is that 16 gallons of tar oils and ¾ton of semi-coke are produced from 1 ton of Northumberland small coal. The paper goes on to discuss the potentialities of low-temperature tar and it is explained that investigation of this aspect of coal distillation is by no means complete. The field of research is said to be one which presents wide possibilities.In conclusion it is claimed that a new situation exists in which a practical process of coal distillation has been evolved in conjunction with the generation of electricity, and that as a result a definite step forward in the better utilization of our most valuable national asset, namely coal, is now due.A full description of the coal distillation plant at Dunston-on-Tyne is given as an Appendix to the paper.

DOI:10.1049/jiee-1.1930.0017

出版商:IEE    

年代:1930

数据来源: IET

摘要:

The paper gives a short account of the development of wireless telegraph apparatus for naval purposes. The historical development is referred to, the wireless telegraph lines required for naval ships are outlined, and the essential requirements and chief features of some of the apparatus used under sea-going conditions are briefly described. The organization for giving effect to the policy of H.M. Board of Admiralty is also indicated.

DOI:10.1049/jiee-1.1930.0021

出版商:IEE    

年代:1930

数据来源: IET

摘要:

A quartz resonator connected between the grid of a valve and either of the other electrodes gives rise to oscillations in the plate circuit when the constants of that circuit satisfy certain conditions. The frequency of the oscillations depends mainly upon the natural frequency of the quartz, and is, therefore, fairly constant when the temperature is constant. In addition to temperature effects, which are not considered in the present paper, variations of frequency can be produced by (i) variations of the air-gaps of the resonator, i.e. the air-gaps between the quartz and the two electrodes of the resonator; (ii) variations of the constants of the plate circuit; and (iii) variations of the inter-electrode capacities and conductances. The object of the investigation is the study of these variations, both theoretically and experimentally.In the theoretical treatment, the quartz is replaced by a circuit made up of an inductance, a resistance and a capacity in series, the whole being in parallel with a second capacity. The validity of such a substitution has been studied experimentally by Dye.The combination of quartz resonator, valve and plate circuit is represented by a network of admittances, from which three circuit equations are obtained; to these is added the fundamental equation of the valve. These four equations yield a single linear differential equation of the fifth order, with constant coefficients. In the case under investigation, it is only required to find the frequency and the amplitude of oscillations after the latter have reached a constant amplitude. This consideration affords a means of reducing the differential equation to one of the same type, but of the second order. From the latter equation, of which the general solution is known, formulæ are developed for the changes of frequency resulting from variations in the resistance and capacity of the plate circuit, in the resistance of the grid leak, in the inter-electrode capacities, and in the air-gap. These formulæ provide useful information as to the influence of each variable on the frequency, and can with advantage be applied to the choice of the best circuits and the best valve for a quartz oscillator.As the oscillations build up after switching on, the average plate conductance of the valve alters gradually. When the amplitude of oscillation has reached its final value, the value of the average plate conductance is such as to annul the damping term, i.e. the coefficient ofdy/dtin the differential equation. From this condition the average plate conductance can be determined for any values of the circuit variables. The amplitude of oscillations in the plate circuit is a function of this average plate conductance.Formulæe are developed which give the conditions for the maintenance of oscillations, and an investigation is made of the variations of amplitude with variations in (a) capacity in the plate circuit, (b) resistance in the plate circuit, and (c) grid conductance.Points of importance in the choice of circuits and valves are deduced from the formulæe and the theoretical curves.Two types of quartz oscillator are investigated, namely, the cases in which the quartz resonator is connected between (i) the grid and the plate of the valve, and (ii) the grid and the filament of the valve.A fairly complete experimental investigation is described. The admittances of the valve and of the circuits were measured, and the equivalent electrical network of the quartz was determined. The behaviour of the quartz oscillator was then investigated by altering in turn each variable in the circuits. The theoretical and experimental results are compared and discussed.The paper does not deal with circuits especially devised for obtaining large outputs from quartz crystals. Its object is the study of the influence of the circuit variables on the frequency and on the power generated as regards the simple Pierce circuits.

DOI:10.1049/jiee-1.1930.0023

出版商:IEE    

年代:1930

数据来源: IET

摘要:

The paper deals with a method of high-frequency resistance measurement employing a variable mutual inductance. The sources and magnitude of the errors likely to occur are dealt with mathematically. The results of coil resistance measurements are given and compared with the calculated values of resistance and with the results obtained by the “resistance variation” method. The application to condenser resistance measurement is considered.

DOI:10.1049/jiee-1.1930.0024

出版商:IEE    

年代:1930

数据来源: IET

摘要:

The author outlines a simple method of testing current transformers. The method is an absolute one and does not call for expensive apparatus or rely on the existence of a number of “standard” transformers.

DOI:10.1049/jiee-1.1930.0025

出版商:IEE    

年代:1930

数据来源: IET