Theory and Design of An Incremental Loading Machine

46 Pages·01.565 MB·English

by  Levitt, Joseph

THEORY ÂHD DESIGH
OF AM
IMCEEMEHTAL LOADIMG MACHIME
THESIS
Submitted in Partial Fulfilment
of the requirements for the
degree of
MASTER OF MECHANICAL ENGINEERING
at the
POLYTECHNIC INSTITUTE OF BROOKLYN
JOSEPH LEVITT AND PAUL SOROS
May 1950
Approved:
sis Adviser
lead tmen-
ProQuest Number: 27591416
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VITA
JOSEPH LEVITT
* ie *
Date of Birth: November 17, 1921
Place of Birth: Binghamton, New York
Undergraduate Education: Cooper Union School of Engineering;
Bachelor of Mechanical Engineering, June, 1944»
Professional Experience;
September 194# - Present: Instructor in Physics and
Mechanical Engineering, Pratt Institute, Brooklyn, N.Y.
September 194*7 - June 194&: Instructor in Physics and
Mathematics, University of Illinois, Chicago, 111.
January 1947 - July 1947: Research Assistant (Diesel
Engines) at Engineering Experiment Station, Pennsylvania
State College, Pa.
August 1945 - December 194&: Mechanical Engineer,
Schwarz Laboratories Inc., N.Y.C. (Consulting Engineers
to the Food and Brewing Industries).
August 1944 - August 1945: Mechanical Engineer, N.Â.C.A.,
Langley Field, Va. (Aerodynamic Research).
Publications;
^Entropy - The Thermodynamic Dilemma,” Penn State
Engineer, April, 1947.
"Wind Tunnel Investigation of Effect of Canopies on
Directional-Stability." N.A.C.A. TH# 1052, May, 194&»
^
The work connected with the present, Thesis was carried
out in the Physics Laboratories of Pratt Institute, Brooklyn,
New York. Construction of the Incremental Loading Machine
was undertaken in February 1950 and completed in May 1950.
The Total amount of time consumed for the entire project was
a little more than 1000 man-hours.
VITA
PAUL SOROS
* *
Date of Birth; June 5, 1926
Place of Birth; Budapest, Hungary
Undergraduate Education; Budapesti Gepeszeti Ipari Kizepiskola
(High School of Metal Technology of Budapest). Grad­
uated in 1944•
Studied Mechanical Engineering at the Jozsef lador
Muegyetem (Jozsef Nador Polytechnic Institute) in
Budapest until 194&'
Publications:
”Uj Konnyusulyu Automotor,” (A New Light-Weight Internal
Combustion Engine), Elet Es Tudomany (Life & Science),
Budapest, March 194#»
”Uj Motorgyatasi Eljarasor,” (New Methods in Motor Car
Engine Manufacturing), Technikus, Budapest, April 194#*
* * # *
The work connected with the present Thesis was carried
out in the Physics Laboratories of Pratt Institute, Brooklyn,
New York. Construction of the Incremental Loading Machine
was undertaken in February 1950 and completed in May 1950.
The total amount of time consumed for the entire project was
a little more than 1000 man-hours.
ACKNOWLEDGEMENT
The authors are greatly indebted to Prof. M. J, Steinberg
of Brooklyn Polytechnic Institute and the Consolidated Edison
Company of New York, who graciously extended his valuable
time in giving assistance, advice, and encouragement, through­
out the entire investigation.
ABSTRACT
# # #
The aim of this investigation has been to design and
construct a machine which will automatically compute, from
the input-output data, the optimum division of load among
a group of power stations comprising any power generating
system.
Various methods of load distribution are described in­
cluding that of the Incremental method which is the most
important as its application results in the attainment of
maximum operating efficiency. The present method of cal­
culating Incremental load distribution is presented.
The mathematical proof of the principle on which the
machine operates is developed; also included, are descrip­
tions of its construction and operation.
Results of tests on the machine are presented and com­
pared with values obtained by straightforward calculation.
While this comparison proves to be quite favorable, the need
for improvement in the existing machine is noted and a revised
design is presented.
TABLE OF CONTENTS
TOPIC PAGE
Introduction.................... 1
Mathematical Proof of the Principle of
Equal Incremental Rates . . . . . . . . . 6
Calculation of Incremental R a t e s .................. 8
Discussion of a Mechanical Device for
Establishing Incremental Loading . . . . 10
Mathematical Proof of Theory of Incrementometer . . . 18
Experimental Verification of Theory.............. 21
Experimental Procedure and Results ................ 26
Conclusions...........................•.......... 33
Bibliography ...................................... 35
TABLE OF FIGURES AND GRAPHS
TITLE PAGE
Fig. 1 - Solution of Typical Load Division
Problem by the Incremental Method.............. 4
Fig. 2 - The Incrementometer.................... 12
Fig. 3 - Bottom Side of Disc Illustrating
Method of Tightening Steel B a n d ................ 14
Fig. 4 - Upper Side of Disc Showing Radial
Lever and Rider ................................ 14
Fig. 5.- Relative Rotation Between Discs ........ 17
Fig. 6 - Free Body Diagram of D i s c ................19
Fig. 7 - Performance Curves of FourP ower Plants . . 22
Table I - Incremental Load Division Among Four
Power Stations.................................. 24
Fig. 8 - Effect of Loading on System Input • • . • 25
Table II - Load Division Among Four Power
Stations as Furnished by Incrementometer........ 31
Fig. 9 - Working Drawing Showing Details of
Present Design of Incrementometer..................VInside of
Lpocket.
Fig. 10 - Working Drawing Showing Details of Cback cover
Proposed Design of Incrementometer ............ /
1 - Introduction
The general problem of power-station operating econ­
omies may broadly be considered to consist of three phases
which are:
1. The provision of sufficient capacity in operation
to insure continuity of service throughout the
system.
2. The selection of the necessary equipment to supply
the load from the standpoint of its effect on the
best over-all system economy.
3. The correct division of load on the equipment which
has been placed in operation.
This Thesis is concerned with the last of these phases.
Even without a detailed explanation it is apparent that
random loading of boilers or turbines in any power plant, or
random loading of individual power plants in a power generat­
ing system would not result in the attainment of the greatest
possible efficiency. This of course has long been recognized
and through the years, many methods of load division have
been developed. In a number of cases the different methods,
for a certain range of operation, result in identical loading.
A few of the methods in use are;
1. Base loading
2. Proportional loading
3. Equal-efficiency loading
4. Incremental loading
To arrive at the correct combination of equipment and
then the correct division of load for the combination placed
in operation, the performance characteristics of each piece
of equipment must be known. With proper equipment available
and station characteristics known, the appropriate solution
of any momentary load-division problem may be "reached.
The different methods of load division will now be dis­
cussed in the same order as stated above.
The method of base loading gives load to the best sta­
tion or machine up to its maximum capacity before any load
beyond its capacity is assigned to the next best station or
machine.
The method of proportional loading consists merely of
plotting the sum of the turbine loads at their full load
points, and connecting these points through zero with straight
lines; from these, unit loads can be scaled off for any given
station load.
In the equal-efficiency method, the ratio of output to
input of the various turbines or boilers must be equal. Where
this scheme is used, a schedule may be made up by maintain­
ing equal efficiencies on a variety of machines, progressively
as the load changes.
It is by means of incremental loading that the minimum
input for any output with any given combination of equipment
in operation is achieved. This method will not of itself
show what equipment should be placed in operation, but with