NEW OR IMPROVED DYNAMO-METRICAL APPARATUS FOR ASCERTAINING AND REGULATING A communication from abroad by
Year: 1879

page_text: LETTERS PATENT to Walter Alfred Barlow, of 6, St. Paul's Churchyard,
London, Patent Agent and Engineer, for the Invention of "NEW OR
IMPROVED DYNAMO-METRICAL APPARATUS FOR ASCERTAINING AND REGULATING
A communication from abroad by Alphonse Mouchablon, of
PRESSURES."
Paris France
Sealed the 30th March 1880, and dated the 3rd October 1879.
PROVISIONAL SPECIFICATION left by the said Walter Alfred Barlow at
the Office of the Cominissioners of Patents on the 3rd October 1879.
WALTER ALFRED BARLOW, of 6, St. Paul's Churchyard, London, Patent Agent
and Engineer. "NEW OR IMPROVED DYNAMO-METRICAL APPARATUS FOR ASCER-
TAINING AND REGULATING PRESSURES." A communication from abroad by
Alphonse Mouchablon, of Paris, France.
It is well known that a weight placed at the extremity of a lever which is free
to turn around an axis exerts an increased effort upon the axis as in the change of
its position it approaches the horizontal.
Upon this principle are constructed several letter weighing devices, and this
axiom has been utilized in constructing the apparatus which forms the subject of
this Invention, wherein the weight by its change of position continually acts to
balance the steam pressure.
This problem can only be practically solved if the organ which directly receives
the pressure of the steam does not produce by friction an important loss of power,
and if on the other hand it absolutely closes the steam passage.
The pressure is received on a diaphragm of sheet steel, for example, or other
material of similar kind, preferably stamped up or domed; but as this diaphragm
is only capable of slight displacements, a combination of levers is employed, so that.
for the smallest displacement of the diaphragm, a relatively great displacement of
the weight destined to balance the pressure will result.
The apparatus is constructed as follows:-The parts work in a boxing, into
which is led a tube fitted with a union for the steam pipe leading the steam the

page_text: pressure of which is to be measured. A cap is fitted upon the end of the tube, and
the diaphragm is secured by screws between the two parts of the cap, and to the
diaphragm a piston or cylinder is bolted and connected to a crank by means of an
arm attached to a weight lever. This lever carries a set of teeth at its extremity
which gears with a pinion, which pinion actuates an arm to which is attached a
weight. The weight will thus at a given moment occupy a position so that it will
equalize the given pressure under the diaphragm, and the weight lever carries a
segment rack in gear with the spindle of an index needle.
By employing the apparatus in an inverso sense, it may be used as a vacuum
indicator, and by employing the pinion of the weight lever to actuate a throttle or 1
other valve, an efficient regulator will be obtained.
According to a modification the displacement of a weight is avoided by using a
spring barrel at the end of a lever gearing by external gear with a curved rack,
which arrangement would be particularly useful upon ships, and in other places
where displacement of a weight by sudden changes of position would be detrimental
to the proper working of the apparatus. The diaphragm piston in this case acts
upon a pivoted lever arm which carries a rack at its extremity gearing with a
pinion which operates the lever arm or spring barrel lever. When the pressure is
removed from the diaphragm, the unwinding of the barrel spring will cause the
barrel to return upon the curved rack, and bring the lever, and with it the indicator 2
needle, back to its zero position.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Walter Alfred Barlow in the Great Seal Patent Office on the 3rd
April 1880.
WALTER ALFRED BARLOW, of 6, St. Paul's Churchyard, London, Patent Agent
and Engineer. "NEW OR IMPROVED DYNAMO-METRICAL APPARATUS FOR ASCER-
TAINING AND REGULATING PRESSURES." A communication from abroad by
Alphonse Monchablon, of Paris, France.
It is well known that a weight placed at the extremity of a lever which is free
to turn around an axis exerts an increased effort upon this axis as in the change of
its position it approaches the horizontal.
Upon this principle are constructed several letter weighing devices, and this
axiom has been utilized in constructing the apparatus which forms the subject of
this Invention, wherein the weight by its change of position continually acts to
balance the steam pressure. This problem can only be practically solved if the
organ which directly receives the pressure of the steam does not produce by
friction an important loss of power, and if on the other hand it absolutely closes the
steam passage.
The pressure is received on a diaphragm of sheet steel, for example, or other
material of similar kind, preferably stamped up or domed; but as this diaphragm
is only capable of slight displacements a combination of levers is employed, so that
for the smallest displacement of the diaphragm, a relatively great displacement of
the weight destined to balance the pressure will result.
In Fig. 1 is represented in vertical section a construction of the apparatus, the
parts whereof work in a boxing, into which is led a tube A fitted with a union A¹
for the steam pipe leading the steam the pressure of which is to be measured.
A cap B is fitted upon the end of the tube A, and the diaphragm D is secured by
screws between the two parts of the cap, and to the diaphragm D a piston or
cylinder E is bolted and connected to a crank F by means of an arm F¹ for turning
around the stud O, and with it the weight lever H thereon. This lever carries a
set of teeth at its extremity which gears with a pinion fixed upon a stud T, which
said pinion in its rotation actuates the weight P and the lever M.
The weight will thus at any given moment occupy a position which will equalize
the given pressure under the diaphragm, and as the lever M carries a segment rack
in gear with the spindle of an index needle, the pressure may be readily indicated
upon a dial face in the ordinary way.
In this construction of apparatus, represented in said Fig. 1, the displacement of
the diaphragm is multiplied by 65 with a weight of about 14 oz. avoirdupois.
It is obvious that by adding another lever a further multiplication of the weight
will result, and thus constitute an excellent manometer for hydraulic presses.
By employing the apparatus in an inverse sense it may be used as a vacuum
indicator, and by employing the pinion T of the weight lever to actuate a throttle
valve turning in a tube, an efficient pressure regulator will be obtained. This
apparatus by such simple modifications becomes equally applicable as an ordinary
manometer or gauge, or a manometer for high pressures, or a vacuum gauge, or a
pressure regulator which may be employed either in distillation or to regulate the
pressure of lighting gas.
According to a modification shown in Fig. 2, the displacement of the weight P
when the position of the manometer is changed, such as aboard ship, for example, is
avoided.
This modification contains at the same time some simplifications of construction
applicable to the manometer shown in Fig. 1. In this arrangement the tube A
is suppressed, and the steam is introduced directly through L. A greater surface
is also given to the diaphragm D in order to increase the sensibility of the

page_text: apparatus. The piece E is worked by the pressure acting on the diaphragm, and it
forces the crank E to turn the stud O around by the lever H, which is terminated
by a rack h. This rack actuates the pinion t mounted on the stud T, which in its
rotation actuates the lever M carrying at its extremity the spring barrel P, on the
axis whereof is a pinion in gear with the fixed rack N, which said rack is fixed by
screws in the slots v', whereby its position may be accurately adjusted. The
stud O carries the index hand.
When the pressure is not exerted upon the diaphragm D, the pinion p will be
returned to the lower part of the rack N by action of the spring barrel P, but as
soon as pressure is exercised on the diaphragm D, the pinion is worked along
the rack N in direction of the arrow, whereby the spring is wound, and thus
opposes an increasing resistance, as the displacement is more considerable, and
consequently acts similarly and serves the same end as the weight P in Fig. 1.
Having now described the nature and particulars of the said Invention,
I claim,―
Firstly. The construction of the manometer based upon the displacement of a
weight to balance the pressure and to measure the same, as herein specified and
shown by the Drawings.
Secondly. The use of the fixed diaphragm operating the piece E, as and for the
purpose herein described and shown by the Drawings.
Thirdly. The construction and arrangement of manometer apparatus wherein the
weight is replaced by a spring, the tension whereof increases in proportions as the
rod M is thrown out of its vertical position, substantially as herein set forth and
shown in Fig. 2 of the Drawings.
In witness whereof, I, the said Walter Alfred Barlow, have hereunto set
my hand and seal, this Second day of April, in the year of our Lord One
thousand eight hundred and eighty.