IMPROVEMENTS IN HYDROSTATIC PRESSES AND THEIR ATTACHMENTS
Year: 1876

page_text: LETTERS PATENT to John W. Hyatt and Thomas S. Crane, of the City of
Newark, in the State of New Jersey, one of the United States of America,
for the Invention of "IMPROVEMENTS IN HYDROSTATIC PRESSES AND THEIR
ATTACHMENTS."
COMPLETE SPECIFICATION filed by the said John W. Hyatt and Thomas
S. Crane at the Office of the Commissioners of Patents on the 17th June
1876.
JOHN W. HYATT and THOMAS S. CRANE, of the City of Newark, in the State of
New Jersey, one of the United States of America. "IMPROVEMENTS IN HYDRO-
STATIC PRESSES AND THEIR ATTACHMENTS."
Our Invention consists in combining the forces of two or more hydraulic presses
in a novel manner, and in modifications of the hydrostatic press, adapting it
especially to be used with low pressures and in the combined form mentioned. It
is also adapted to the use of steam or elastic fluids as well as water, and will be
fully understood by reference to the annexed Drawings, of which Fig. 1 is an
elevation of a press constructed entirely with diaphragms m, m, shown in section in
Fig. 3, and in plan in Fig. 2.
Fig. 4 is an elevation of a press constructed with oblong bags G, G, shown in
section in Fig. 9, and in plan in Fig. 5.
Fig. 6 is a plan of a bag made with a metallic frame and bolts around the
edge.
Fig. 7 is a plan of a bag with rivets around the edge, and adapted to fit a
press externally square in form.
Fig. 8 is a section of the perforated washer described as distributing the water
from the pipe x to any bag into which it is clamped.
Fig. 10 is a plan of said washer, and Fig. 11 a plan of the clamping
nuts.
To describe the construction and operation of our compound press we refer to
Figs. 1, 2, & 3, in which A is a plate of metal depressed for the greater part of its
area, a raised margin being left around the edge, to which to which is attached by a
suitable joint (as as a bar of metal held by screws) a sheet of semi-elastic material, as
[Price 6d.]

page_text: canvas or rubber packing. This plate A we call a diaphragm plate, and the flexible
material the diaphragm m. At intervals of a few inches above this plate, and
resting by contiguous connections or supports E upon the same floor as A, is a
series of other diaphragms plates A¹, A¹¹, &c.
At C are seen pipes for introducing fluid under the diaphragms. These are all
connected to a supply pipe J and to a tank T, which, if water be used, is filled with
that fluid.
It is obvious that if steam is used and the pressure be admitted to the tank
above the water, as by cock L, it will be forced under each diaphragm with &
pressure corresponding to that of the steam.
Above each diaphragm plate is placed a pressure plate P, which connects with
each adjoining plate P by some projection, which we make preferably of the form
shown at e, e¹, the projections marked e being narrow enough to draw out between
the plates A, A¹, and those marked e¹ long enough to transmit the pressure from
one plate P to another.
The platen D is furnished with projections similar to and connecting with those
on the plates P.
Through the corner of each diaphragm plate is arranged a rod g, which serves to
connect the plates A, sustaining the hydraulic pressure with the cap H which
resists the pressure.
The castings themselves can be so made as to support this strain without the aid
of any extraneous rods or ties.
When pressure is applied to the water in the tank T, it is plain that all the
diaphragms will be expanded simultaneously, and the pressure plates P will
transmit their combined forces to the platen D through the projections e, e¹, con-
necting them and the platen togather. And to release the platen from such
pressure it is only necessary to shut off the steam from the tank and liberate the
enclosed vapour, when the weight of the platen and plates P will force the water
from the diaphragms back into the tank.
The liberating valve M is placed at the point at which it is desirable to
maintain the water in the tank T, and any condensed water is then discharged
with the waste steam.
It will be noticed that while the strain upon each pressure plate is limited to the
force exerted by one diaphragm the pressure exerted upon the projections e, e¹,
increases from the bottom to the top of the press until the platen D is reached,
which receives the power of all the diaphragms below that point, the platen also
receiving the direct pressure of the top diaphragm in contact with it.
The pressure upon a diaphragm 20 inches square would be ten tons at a pressure
of 50 lbs. to the square inch; and ten such diaphragms, with their pressure plates P,
can be included in a space of 45 inches, constituting a hundred ton press.
With a pressure of 100 lbs. per square inch readily obtainable from a steam
boiler the same diaphragms would exert a force of 200 tons.
In Figs. 4 & 5 is shown another mode of utilizing low pressures by the
accumulating process described above by the use of flexible bags.
A bag G, Figs. 6 & 7, is made of two of pieces of flexible material suitable for
a diaphragm joined strongly at the edges, and provided with a hole to admit the
pressing liquid.
In Fig. 6 the edges of the bag are shown clamped between two metallic
frames by bolts or rivets, the substance of the bag being put loosely into the
frames that it may expand easily under pressure.
In Fig. 7 the bag is shown revited continuosly around the edge, the heads of
the rivets serving as a clamp.
In Figs. 4 & 5 the bags G, G, are shown made pieces of hose clamped across
the ends with straight or curved bars of metal rivitted fast to the bag.
As such bags are readily removed from the press, not being secured to their
supporting plates B, B, as the diaphragms are, there is no need of constructing the
pressure plates P1, P1, with projections like e, e¹, outside the margin B. Holes

page_text: a, a, are therefore made in the corners of the bag plates B, and the pressure plates
P1, P¹, are provided with studs i, i, i, i, projecting upward through the holes to the
pressure plates above.
With rectangular bags like those shown in Figs. 5 & 6, the studs are
arranged in a parallelogram, but with a round bag, as shown in Fig. 7, the plan
of the press is square, the tie rods g, g, holes a, a, and studs i, i, being placed in
the corners of the plates B & P¹.
To facilitate the removal of the bags from the press for renewal or repair we
have devised the form of pipe connection shewn in Figs. 8 to 11.
A perforated washer 8, shewn in plan at Fig. 10, and in section in Fig. 8, is
placed inside the part of the bag which projects from the press, and the sides of
the bag clamped against it the radial passages c serve to conduct into the bag
any fluid entering at the centre hole d. To clamp the bag thus two nuts p, p, are
shown in Figs. 8 & 11, which fit the exterior of the distributing pipe x, the
pipe being perforated where it passes through the washer.
Where a rapid motion of the press is required and a free passage for the water is
essential, we employ the arrangement of bag connections shown in Fig. 9, where
short pieces of pipe n, n, are employed between the bags G1, G¹, and a rod o
passing through all the bags and pipes is secured by a screw thread at both ends,
so that it can be readily removed to take one or more bags from the press. An
inlet admits water inside the pipes n, whence it passes to the bags through the
perforated washers 8, 8.
We commonly make the plates B & P¹, Fig. 7, of curved section, as shown in
Fig. 12. This form affords greater strength with less outlay of material.
From the above description it will be seen that our Invention may be termed a
compound hydraulic press, and it furnishes a means of exposing an iminense area to
a low pressure, such as is easily obtained from a steam boiler or from city water-
works, &c., and that it presents a cheap and effective mode of transmitting the
combined pressures without extraneous parts or the occupation of a large space.
It will be seen that the action of the diaphragm and bag described above are
precisely similar, and might be termed the action of a flexible piston rising and
falling alternately in the space in which it is confined. This mode of construction
also dispences with either a hand or power pressure pump which often costs nearly
as much as the press to which it is attached, and which, as well as an accumulator,
often used as a reservoir of liquid under pressure, is far more likely to get out of
order than the simple apparatus described above, which is peculiar in its freedom
from moving parts susceptible to wear and derangement. We have devised a mode of
exerting some force upon the material exposed to the action of hydraulic presses
before the hydraulic power is applied, the same being illustrated in Fig. 4,
where the head of the press K is shown with a nut or screw thread, through
a screw S passes, terminating at the top in a hand wheel I and at the bottom in an
expansion capable of resisting the force of the press, or if necessary in a connection
to an inverted platen, which may rise and fall with the screw without turning
around as the screw revolves.
Handles N are shown insorted in the rim of the wheel I, but the same may be
furnished with holes, or the head of the screw with sockets for the insertion of
a lever, or several screws may be operated by any means desired. With this
construction work of various thicknesses may be done in the same press without
the aid of blocking, as the movement of the screw compensates for variations.
Soft substances, as leather, printed goods and fabrics, may be subjected to a
moderate pressure by the screw before the hydraulic pressure is applied, thus saving,
in cases where the pressure is produced by a pump, great delay in securing the
requisite pressure upon the work.
In the compound presses described above, in which the movement is limited to a
few inches, this appliance is especially desirable, as the material to be pressed can
be clamped firmly by the screw to save all the movement possible of the hydraulic
platen; or the hydraulic platen itself may be forced against the work prior to

page_text: using the full power of the press by a low pressure cylinder, as shown in Fig. 14,
where D is the tine platen of the press, and D¹ a false platen supported by cylinder
A and piston B, the cylinder being connected by pipe W to a low pressure reservoir,
from which the water would be delivered more rapidly than from a pressure pump.
When the cock y is closed the water in the cylinder A would easily sustain the
full load of the press, and the outlet z would discharge the water rapidly when the
pressing was completed that the work might be removed from the press. We have
also devised an arrangement for pressing plastic substances that require treatment
in a soft condition in such cases as require the application of heat to maintain that
condition in the press.
If such material is heated on a steam table detached from
the press it is liable to become chilled before it is fully pressed, and if arranged
upon a hot table in the hydraulic press, difficulty has been experienced in removing
and cooling such objects with dispatch and without liability to change of form.
To press such substances as hard rubber or vulcanite, celluloid, and other
plastic compositions to the best advantage they should be operated upon while hot,
and cooled when under pressure. This has sometimes been accomplished by
circulating hot water or steam over the dies during the continuance of the formative
pressure, and cold water over them at the close of the operation; but when the hot
water or steam penetrates the dies of concave form or containing depressions, fluid
sufficient to fill small cavities lodges in the same, causing defects in the article when
subjected to pressure.
In Fig. 13 will be seen the arrangement we have devised for drying such dies
in vacuo before submitting them to the formative pressure.
A vacuum box p is provided in the opening of the press and furnished with
a stuffing box q fitting a piston on the cap H¹ to keep the box tight when in
motion.
An air-tight door f is made to fit one side of the box that the piece to be
pressed as a billiard ball may be introduced with its die h.
The parts named are drawn in section to show the arrangement clearly.
When the die is introduced and the door closed, steam is admitted by the
pipe u to the vacuum box p, and the die hand ball warmed to the requisit
degree.
To dry out the die h, which is now at a temperature to vaporize water readily
in vacuo, the piper communicating with a vacuum chamber t is opened and the
box exposed to the vacuum a short time.
All the moisture having thus been discharged from the die the piper is closed and
the hydraulic pressure applied to the die while still warmed by the heated metal
surrounding it.
While thus under pressure cold water is admitted to the box p by the cock k and
the die cooled to the needful degree, the water flowing out of a waste pipe as it
becomes warmed.
The vacuum may be maintained in the chamber t by a jet of water through the
pipe V mingling with the steam flowing from the box p; or an air pump can be
employed for the purpose.
In practice we find the jet entirely adequate. This arrangement, with its
facilities for heating and cooling, we have found to greatly increas the working
capacity of any press to which it is applied, and claim its application to all
machines used for pressing substances requiring the application of heat and cold in
the manner described.
We also claim as new the use of the screw adjustment described above for
clamping materials in any form of hydrostatic press for the purpose described, and
the application of steam pressure directly upon the water to force the same into
hydraulic presses of any description, having used the same in cylinders 34 inches
in diameter at 50 lbs. pressure to produce a force of 22 tons.
Having thus described our Invention, what we claim and desire to secure by
Letters Patent is as follows:-

page_text: First. A hydraulic press constructed with one or more diaphragms or bags as
described above and operated by steam from a boiler in connection with an inter-
mediate tank or its equivalent, substantially as shown and described.
Second. The arrangement of a steam boiler, a hydrostatic press of any form of
construction, and an intermediate tank in which the steam pressure is converted
into water pressure, substantially in the manner described.
Third. The compound hydraulic press constructed by arranging two or more
diaphragms or bags, substantially in the manner described in a hydrostatic press,
so that their forces may be concentrated on the platen of the press or its
equivalent.
Fourth. In a compound hydraulic press the pressure plates P, P, constructed
with projections e, e¹, and operating in combination with the pressure chambers
contained in the diaphragms m, m, or bags G, G¹, upon the platen D, substantially
in the manner shown and described.
Fifth. In a compound hydraulic press, the pressure plates P1, P1, furnished with
studs i, i, for transmitting and adding the pressure of one to the other through
or past the intervening supporting plate B, substantially in the manner described.
Sixth. The hydraulic press, consisting of a bag constructed substantially as
described, operating in combination with the plate B, pressure plate P¹, or platen
D, cap H or K, and connections g, g, or their equivalent from plate A to cap H
or K.
Seventh. In combination with a compound hydraulic press, the pipe connections
to bag G formed by compressing the sides of the bag or a connection thereto
against a perforated washer 8, substantially in the manner described.
Eighth. Curving the supporting plates B and pressure plates P¹ in a compound
hydraulic press, substantially in the manner shown and described.
Ninth. The combination of a screw or screws with the head of a hydraulic press
to lessen the movement of the platen and hydraulic appliances, substantially in the
manner shown and described.
Tenth. The combination and arrangement of the auxilliary cylinder A and piston
B with the platen D of a hydraulic press for advancing the same to its work at each
stroke before applying the hydraulic pressure.
Eleventh. In combination with a hydraulic press or equivalent pressing
mechanism, the box vacuum p constructed and operated substantially in the
manner described.
In witness whereof, we, the said John W. Hyatt and Thomas S. Crane, have
hereunto set our hand and seals, this Third day of June, in the year of our
Lord One thousand eight hundred and seventy aiv
JOHN WESLEY HYATT.
(L.S.)
THOMAS SEXTON CRANE.
(L.S.)