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American Machinist August 30 1884, vol. 7 no. 35 pg. 2,3,4
4pg 3
4pg 3
American machinist august 30 1884 vol 7 no 35 pg 4.
How to build your own wood beam 10 ton foundry crane 1884
How to build your own wood beam 10 ton foundry crane 1884
AMERICAN MACHINIST [AUGUST 30, 1884
inspector at headquarters, resulted in an urgent request for a thorough
inspection being received by the firm from the insurance company. When
this was made, ' the inspector found the plates of the boiler pretty well
cleared of -scale, but a whitish deposit had settled in the cross water tubes,
or Galloway tubes, and, on these being struck with a hammer from the fire
side, a hole was easily knocked through every tube in the boiler. The
rnuriatic acid, for which "spirits of salt" is only another name, neutralized
only to the extent of the calcium salt formed by the oyster shells which had
been dissolved in it, appeared to have settled principally on the inclined
surfaces of the cross water tubes, and corroded them internally to such an
extent that every tube in the boiler required renewing. Any steam user who
is in want of an engine-man of an enterprising and
experimental turn of mind has now the chance of being suited, as we
believe the man, after his few months' attempt to get a place where he will
be better appreciated, will be disposed to hire out his, services at a
comparatively low figure. It is not long since an engine=man wrote us that
he had been trying the effect of oil of vitriol (sulphuric acid) in his boilers,
and if he neglect the warning we gave him, and goes on fooling with his
acids, etc., much longer, there will probably be another good man at liberty,
.f, indeed, nothing worse happen.-Meehanieal World.
inspector at headquarters, resulted in an urgent request for a thorough
inspection being received by the firm from the insurance company. When
this was made, ' the inspector found the plates of the boiler pretty well
cleared of -scale, but a whitish deposit had settled in the cross water tubes,
or Galloway tubes, and, on these being struck with a hammer from the fire
side, a hole was easily knocked through every tube in the boiler. The
rnuriatic acid, for which "spirits of salt" is only another name, neutralized
only to the extent of the calcium salt formed by the oyster shells which had
been dissolved in it, appeared to have settled principally on the inclined
surfaces of the cross water tubes, and corroded them internally to such an
extent that every tube in the boiler required renewing. Any steam user who
is in want of an engine-man of an enterprising and
experimental turn of mind has now the chance of being suited, as we
believe the man, after his few months' attempt to get a place where he will
be better appreciated, will be disposed to hire out his, services at a
comparatively low figure. It is not long since an engine=man wrote us that
he had been trying the effect of oil of vitriol (sulphuric acid) in his boilers,
and if he neglect the warning we gave him, and goes on fooling with his
acids, etc., much longer, there will probably be another good man at liberty,
.f, indeed, nothing worse happen.-Meehanieal World.
Insert Formula 3 for V, and Formula 4 for T in Formula 2, and we have:
F. M2irRnX 4n_ M8irRn2
60 60 602 5
The mass M= W or the weight of the body
divided by the acceleratrix of gravity, which
is g=32.17. Insert this value for M, in Formula 5 and we have:
__ W87rRn2 WRn$
F 32.17X60X60 4608 5 That is to say, the mean force (in time) of inertia of the reciprocating parts of a steam engine is, for
each half-stroke,
F. WRn2
4608 5
This mean force of inertia acts as resistance in the first half of the stroke, and as motive force on the crank-pin in the last half
of the stroke.
It is supposed in this demonstration that the connecting-rod is infinitely long compared with the length of the crank, which
supposition will not much affect the force of inertia when the connecting-rod is three times, or more the stroke.
Example 5.--The weight of the reciprocating parts of an engine is W=1,000 pounds, making n=265 revolutions per minute with
stroke 16 inches, or R=3 of a foot. ` Re-
e~---~
t-- \ 3i
The maximum force of inertia, which is at the beginning and end of the stroke, when 5=o and cos.=1, is:
WRn2
F — 2930 9
The mean force of inertia in each half stroke is one-half of the maximum force, or: WRna
F=5860 10
Example 9, required the maximum force of inertia of the reciprocating parts of an engine of the same dimensions and
revolutions as given in example 5:
W=1000. R=3, n=265
Force of inertia
=--1000 X 2X 2652
F 3X2930--15978.4 pounds.
As the force of inertia is proportionate to the cosine of the angle 0 of the crank, it is very easy to lay down a diagram for inertia
as represented by the accompanying illustration.
With the radius of the crank A C, and center C, draw the circle A D B E, which will be that described by the center of the crank
pin. Divide the quadrants A D and D B into any number of equal parts, say four, as shown on the illustration. Through
I
bly caused by the motion of the inertia mass, and is not the same as that of the cross-head on which the instrument is fixed,
and it can therefore not give a true diagram. The calculations and scale measurements necessary with this inertia instrument
are unreliable, and require more time and expense than that of calculating the inertia correctly by formula 9, which formula is
ready for use without operation of the engine. The inertia instrument may be considered useful by those who do not
understand dynamics of matter, and who have no faith in mathematical demonstrations.
The back-action horizontal propeller engines, constructed by Chief Engineer Isherwood, were much complained of in
technical journals, which stated that the enormous reciprocating masses of iron absorbed most of the power by being set in
motion and stopped at each stroke." The fact is that there was no power at all lost by that means, but the inertia of those heavy
reciprocating parts acted beneficially on the uniform motion of the engines, particularly when high expansion was used. The
forces of inertia of heavy reciprocating parts, however, act to shake the vessel, which i a great inconvenience in small
steamers, but engines can be constructed in which the forces of inertia neutralize one another.
Personal.
A. G. Brown, for some time past assistant superintendent at the Westinghouse Machine Company's Works at Pittsburgh, has,
at his request, been transferred to the New York office of that company. Mr. Brown's health has been somewhat impaired, as
he believes, by close confinement to the shop and drawing-room (he having sole charge of the latter at Pittsburgh), and he
believes that outside engineering work for a time will be beneficial. Mr. Brown has many friends in this section, who wish him
every success.
Cotton Picking Machine.
"Bill Arp" gives the following descriptio of a new cotton picking machine, the inve tion of Mr. Mason, of South Carolina. `` T
Inertia.
BY JOHN W. NYSTROM.
In an article on "Inertia Instrument," by E. F. Williams, of Philadelphia, which appeared in the AMaaaegx MACHINIST for the 9th
of August, it is stated about inertia that "like other great subjects, this one will require years for its investigation, and many.
years may yet be required for that refinement of knowledge which will subject the mighty inertia forces of the reciprocating
parts of an engine to the will of man." This statement encouraged me to venture upon an elucidation of the subject in
question, as I have frequently noticed that this subject is not so generally understood as it
Cotton Picking Machine.
meat of knowledge which will subject the mighty inertia forces of the reciprocating parts of an engine to the will of man." 'hits
statement encouraged inc to venture upon an elucidation of the subject in question, as I have frequently noticed that this
subject is not so generally understood as it ought to be.
The mighty inertia is immutable, and will always be independent of the will of man.
Inertia is the incapability of a body to change its own state of motion or rest.
Force of inertia is the resistance of a body free to move, against any external force applied to change that body's state of
motion or rest.
The applied force and the force of inertia are action and reaction, which forces are alike.
This subject is the first lesson in dynamics of matter, namely: The , force F, is to the mass M, as the velocity V, is to the time T.
That is, a force F, applied to a mass M, at rest, but free to move, will give that mass a velocity V, in the time of action T.
F=force of action in pounds.
M=mass of the body acted upon. W=weight of the body in pounds. V=velocity in feet per second which the
body has attained in T seconds.
T=time of action in seconds.
F:M=V:T. 1 Momentum of time FT = MV, momentum of motion.
Force of inertia F = TV 2
In the case of the working of a steam engine, the reciprocating parts, which constitute the mass M, have attained their
greatest velocity V, when the piston is at half-stroke, when its velocity is equal to that of the crank-pin, namely:
VelocityV= 2 ~n
3
R=radius of the crank in feet.
n=revolutions per minute of the engine.
The time T, in which the piston moves half-stroke, or the crank moves one-quarter of the circle, will be
T =4n 4quired the mean force of inertia of the re-
ciprocating parts.
1000 X 2 X 2652
F= 3X4608 =10160 pounds.
The actual force of inertia of the recipro-
cating parts at any position of the crank from the beginning of the stroke, is found as follows:
=angle of the crank from the beginning of the stroke. Then the velocity of the reciprocating parts at any position of the crank will
be :
V27rRn Sin. _ 60 6 The force of inertia of a moving body is
appreciated only when the motion is accelerated or retarded. When the reciprocating parts move with a uniform velocity, as is
the case when the crank passes 90 degrees, or is at right angles to the center line of the engine, there is no force of inertia.
The maximum inertia is at the beginning and end of the stroke, and it increases and diminishes as the cosine of the angle 4)
of the crank.
This problem cannot be properly solved without the aid of the calculus, which I do not desire to use in the AMERicAN
MACHINIST, for the reason that I know that its readers object to complicated mathematical demonstrations. There is a way of
solving the problem approximately by calculating the force of inertia for a very small angle of the crank, say for one degree.
F,=WRna (sin.—sin.oi) 7
51.15.
in which 0-01=1°.
The correct formula derived from the calculus is as follows:
WRn2cos.¢
F — 2930 8the division points draw the rectangular ordinates A e, bf, c g, d h and C D. With A as a center, draw the are C
e, which will cut A e at e, then A e represents the maximum inertia at the beginning of the stroke; the line A C B being the
direction of the center.
line of the engine.
When the crank is in the position C 1, the line b Cis the cosine for the angle b C i . With b as center draw the are C f, then b j
represents the force of inertia in that position of the crank. When the crank is in th( position cg or 0=45°, then c Cis the cosine,
and with c as the center draw the are C ly, then c g represents the force of inertia, anil in the same way d Ti represents the
inertle when the crank is in the position C 3. When the crank passes the position C Jl at right angles to A B, the motion of the
reciprocat. ing parts is uniform and exercises no Inertia. Now join the points e, f, g, Ti, and C, which will be a straight line, and
the shallot tri. angle A e C represents the diagram of inertia in the first half part of the stroke, which inertia is negative or acts
as resistance to the motion.
The diagram C k B for the other half of the stroke is constructed in the same way, but represents positive inertia which acts
with the motion as motive force.
It is supposed in the forgoing demonstration that the rotation of the crank is uniform or regulated by a fly wheel.
The ordinates A c and B k, represent the maximum inertia given by formula 9, and any other ordinate in the diagrams is given
by the formula 8.
The inertia instrument, invented by Mr. E. F. Williams, it appears, gives a curved line in the inertia diagram, which error is
proba-
"Bill Arp" gives the following description of a new cotton picking machine, the invention of Mr. Mason, of South Carolina. "The
inventor showed me the little revolving tubes that pick the cotton from the bolls. It is
seven inches long and about 14 inches in
diameter. 'lids little thing is the invention. All the rest of the contrivance is to put it in motion. Your dozen of them will be working
at once on it cotton stalk, and if there is any cotton open they will find it. There are two upright cylinders three feet high, that
straddle a cotton row like a sulky plow straddles it row of corn, and these little tubes revolve horizontally in the cylinders. They
turn round and round rapidly. The eylin(lers roXolvo on their axis, and these tubes revolve on theirs as they follow the cylinders
round and round. They are sure to touch
every boll, and if the cotton has opened and swells out a fraction of an inch the little delicate points of the pickers get it and roll
it all out in an instant, and by a reversed motion unload it on a platform, and from there it is carried up and put in a sack and
packed until it is full.
"Horse power pulls the machine along the row. The machine weighs 300 pounds. Some of them are made for three-feet
cotton, and some for four and some for five. I saw the little spindles set to work on cotton bolls half opened, and they left
nothing; and yet they will revolve in your hand and not hurt you or prick you. There are 300 sharp points in each spindle. They
are just under the surface, and will catch the lint, but not catch your flesh or the leaves or the stems. The imperfect machine of
last year picked 300 pounds an hour. The perfect machine which he has now is expected to pick 600 pounds an hour. Mr.
Mason has his own machinery, makes his own lathe and his dies and stamps and wheels and everything. He is backed by
capital unlimited, and has refused a million dollars that was offered him. He is making large machines for Texas and
Arkansas, and snutller ones for the Eastern States. IIis plan is to charge a royalty, and
American machinist august 30 1884 vol 7 no 35 pg 3.
How to build your own wood beam 10 ton foundry crane 1884
How to build your own wood beam 10 ton foundry crane 1884
American Machinist August 30 1884, vol. 7 no. 35. pg 2
American machinist august 30 1884 vol 7 no 35 pg 3.
How to build your own wood beam 10 ton foundry crane 1884
How to build your own wood beam 10 ton foundry crane 1884