from Steam and other Engines.
Year: 1885

page_text: from Steam and other Engines.
I, GEORGE SELLERS of Batley in the County of York Consulting Engineer do
hereby declare the nature of this Invention to be as follows:-
The object of this Invention is to enable diagrams to be taken from compound
engines to more advantage and so to save subsequent reduction.
It is the present practice to take the diagrams from the several cylinders of a
compound engine (be they two or more) all to the same length and afterwards to
reduce the longitudinal scale of the diagram from the smaller cylinder or cylinders
so that the proportion of the length scales of the diagram and the proportion of
the areas of the cylinders may accord.
My invention affords facilities for taking the several diagrams in the first
instance with the proper proportional length and if desired all on the same paper
in their proper relative positions and so as to indicate at a glance when the
theoretical curve is drawn in, how far they differ from theoretical proportions and
clearly show piston and slide valve leakage.
I provide a graduated scale on the top of the revolving barrel and I use with
this a square with a T head made to the curvature of the barrel. With the aid of
these I divide the paper when on the barrel to accord with the proportions of the
cylinders, then when taking the diagrams I adjust the connection of the indicator
barrel with the reciprocating part so that the length of each diagram may be made
to accord accurately with the space previously set out on the paper to receive it.
For this purpose I use a contrivance for readily adjusting the length of the cord
which gives motion to the paper cylinder, this adjuster consists of a frame holding
a small drum round which the cord passes, and is so arranged that this drum can
be rotated by hand but is prevented from slipping by a ratchet and pawl or by &
wheel and endless screw.
I make indicators with barrels of larger size than at present, and with leverage
so arranged that the height of the diagram may be increased so that the diagrams
from the several cylinders may be taken in their proper positions on the same
paper to a scale admitting of their being represented with accuracy.

page_text: ว
from Steam aud other Engines.
I, GEORGE SELLERS of Batley in the County of York Consulting Engineer do
hereby declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
The object of this invention is to enable diagrams to be taken from compound
engines to more advantage and so to save subsequent reduction.
It is the present practice to take the diagrams from the several cylinders of a
compound engine (be they two or more) all to the same length and afterwards to
reduce the longitudinal scale of the diagram from the smaller cylinder or cylinders
so that the proportion of the length scales of the diagram and the proportion of the
areas of the cylinders may accord.
My invention affords facilities for taking the several diagrams in the first
instance with the proper proportional length and if desired all on the same paper
in their proper relative positions and so as to indicate at a glance when the
theoretical curve is drawn in how far they differ from theoretical proportions and
clearly show piston and slide valve leakage.
I provide a graduated scale on the top of the revolving barrel and I use with
this a square with a T head made to the curvature of the barrel. With the aid of
these I divide the paper when on the barrel to accord with the proportions of the
cylinders; then when taking the diagrams I adjust the connection of the indicator
barrel with the reciprocating part so that the length of each diagram may be made
to accord accurately with the space previously set out on the paper to receive it.
I make indicators with barrels of larger size than at present and with leverage
so arranged that the height of the diagram may be increased so that the diagrams
from the several cylinders may be taken in their proper positions on the same
paper to a scale admitting of their being represented with accuracy.
In order that my said invention may be most fully understood and readily
carried into effect I will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 represents a set of diagrams taken in accordance with my invention
from a quadruple engine in which each successive cylinder is of twice the capacity

page_text: paper is lapped around the barrel and retained in the usual way. The scale
marked X is engraved around the top of the indicator barrel.
In preparing to take a series of diagrams in position for immediate comparison
and investigation, the length from A to C, is taken to represent the capacity of the
largest cylinder, then a length from A to D is taken to represent on the same scale
the capacity of the smallest cylinder, and by the aid of the square shown by the
Figures 2 the line D, E, is drawn then the distance A. F is taken along the scale to
represent the capacity of the smaller of the two remaining cylinders and by the aid
of the square a line F, G, parallel to A B is drawn. Finally, another distance A H
is taken to represent the capacity of the remaining cylinder and by the aid of the
square the line HI is drawn. This being done I proceed to arrange the instrument
to take the diagram say first from the largest or low pressure cylinder. I connect
the drum of the indicator in the usual way with the moving part of the engine so
that the stroke of the indicator diagram shall be one complete rotation or say from
the zero to the hundredth degree of the scale. I also carefully adjust the length
of the cord so as to obtain a diagram commencing on the line A B.
In order to effect an accurate adjustment of the length of the diagram it is
convenient to use an adjustable lever such as is shown by Figures 3, in which K
is a pivot carried in a stationary bearing secured in any convenient position
and L L are arms on opposite sides of the pivot K; the arin L' is of double the
length of the arm L. The arm L is slotted and receives the slider M within it;
it is also graduated and the slider can be set in accordance with these graduations
and there clamped by a winged nut N. It is obvious that if the slider be set to
the 50th degree of the scale marked upon the drawing the motion of the stud upon
the slider will be one-half of that of the other end of the lever, the distance of this
point from the centre being twice that of the stud when so set. Similarly if the
slider be set to the degree 25 of the scale the motion of the stud will be a quarter
of that of the other end of the lever, and so, by a suitable adjustment, any desired
proportion can be arrived at.
When the instrument has been adjusted the diagram of the low pressure cylinder
represented by the area P in Figure 1 is drawn. This having been done the
apparatus is next set to draw another of the diagrams; it is not important which
but say the diagram of the next cylinder in order of size. By the aid of the lever
shown by Figure 3 the stroke of the indicator barrel is now adjusted so as to be
equal to the distance from the line A B to the line H I only, which, in this case, is
at the fiftieth degree of the scale. This having been done the diagram is taken
from the second cylinder; it is represented by the area Q of the diagram. Another
adjustment of the stroke of the indicator barrel is then made so that the stroke
shall extend from the line A B to the liue F G and the cord also having been
adjusted the diagram is taken from the next cylinder. It is represented on the
drawing by the area R. Finally the indicator is adjusted so that the stroke of the
barrel may be from the line A. B to the line D E in this case this distance corre-
sponds to twelve and a half degrees upon the scale. Then the diagram from
the high pressure cylinder is taken and this is represented by the area S in the
figure.
In some descriptions of engines it is necessary in the several diagrams to reverse
the direction of motion of the paper barrel relatively to the part of the engine from
which motion is imparted to it. This can be effected by the use of a reversing
pulley around which the cord leading to the barrel is caused to make a half turn.
When the compound diagram has been produced I proceed to draw on the paper
a theoretical expasion curve, starting from the summit of the compound diagram.
Within the area which this curve will enclose the areas P, Q, R, S, will all lie and
the parts of the main area uncovered by the parts P, Q, R, S, will indicate where
and to what extent the result falls short of the standard applied. It is not
indispensible that the scale D should be engraved upon the barrel of the indicator,
it may be engraved upon a band of sheet brass which may be lapped around the
indicator barrel at its upper end and held in place by india rubber or other springs,

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is :-
1. The apparatus for taking indicator diagrams from compound engines each
diagram in its proper position on the indicator paper so that the resulting com-
pound diagram may be directly compared with a theoretical diagram substantially
as described.
"
2. My improved apparatus for taking indicator diagrams from steam and other
engines substantially as herein described.