IMPROVEMENTS IN THE CON- STRUCTION OF VACUUM PANS, AND IN THE CONSTRUCTION OF AND MODE OF DRIVING VACUUM PUMPS TO BE EMPLOYED THEREWITH, PARTS OF WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO OTHER PUMPS."
Year: 1875

page_text: LETTERS PATENT to Alfred Fryer, of Wilmslow, in the County of
•
Chester, and James Bingham Alliott, of Radford, in the County
of Nottingham, for the Invention of "IMPROVEMENTS IN THE CON-
STRUCTION OF VACUUM PANS, AND IN THE CONSTRUCTION OF AND MODE OF
DRIVING VACUUM PUMPS TO BE EMPLOYED THEREWITH, PARTS OF WHICH
IMPROVEMENTS ARE ALSO APPLICABLE TO OTHER PUMPS."
PROVISIONAL SPECIFICATION left by the said Alfred Fryer and
James Bingham Alliott at the Office of the Commissioners of
Patents, with their Petition, on the 18th December 1875.
We, ALFRED FRYER, of Wilmslow, in the County of Chester, and
JAMES BINGHAM ALLIOTT, of Radford, in the County of Nottingham,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE CONSTRUCTION OF VACUUM PANS, AND IN THE. CONSTRUCTION OF AND MODE
OF DRIVING VACUUM PUMPS TO BE EMPLOYED THEREWITH, PARTS OF WHICH Iм-
PROVEMENTS ARE ALSO APPLICABLE TO OTHER PUMPS," to be as follows:-
Our improvements in vacuum pans consist in improved methods of
forming the lower part of the pan and inserting the heating tubes. At
1

page_text: present the interior heating surfaces are usually composed either of
spiral worms, through which steam circulates, or of straight tubes
arranged much as in a multitubular boiler, the liquid to be evaporated
occupying the inside of these tubes, which are surrounded and heated
by steam. In either case should a leak occur in any of the tubes
almost the whole of the pan must be pulled to pieces, and usually the
joints of all the air and steam pipes connected with it must be broken
in order to remove the damaged part for repair, and. thus any repair is
costly in money, and still more costly in time, trouble, and annoyance.
Our improved vacuum pan is made with a bottom formed by pre-
ference of cast metal, either brass or iron being usually employed. The
bottom may if desired be partially jacketed with steam, and in this case
the steam jacket may be cast on to the bottom on its sides at varying
heights, and on different sides of the pan we form a number of plane
surfaces of equal size, which we prefer to make vertical or nearly so.
In these plane surfaces we form openings, which are closed by covers
bolted on to them. Into each of these covers we insert a coil, serpentine,
or grid of heating tubes, which is attached at one end to a steam pipe,
while at its other end is an outlet for any water which may be con-
densed in it. As there are several of these grids or serpentines in each
pan, and as each grid or serpentine with the cover to which it is
attached may be like every other grid or serpentine with its cover
belonging to the same pan by providing a single spare serpentine and
cover it is easy at any time if a leak should occur in one of the
serpentines to stop the pan, remove the leaky serpentine without pulling
the pan itself to pieces, replace it by the sound, spare, serpentine, and
after a very short delay get the pan to work again, while the damaged
part can be repaired at leisure.
It will be obvious that if all the serpentines were put in on the same
side of the pan they could not be placed close above one another, but
by placing every alternate serpentine on another side of the pan (or at a
different angle) it will be obvious that they may be placed as close above
one another as is desired.
Vacuum pumps as at present usually made are unable even theore-
tically to produce a perfect vacuum, because the valves by means of
which the air or vapour to be exhausted enters the pump require some
power to open them, and thus air or vapour of very low tension could

page_text: never get into the pump at all. In order to remedy this evil we
construct a pump of which we prefer to make the working barrel
horizontal. This working barrel we make about double the length of
the stroke of the piston of the pump, while we prefer to make the piston
itself nearly but not quite the length of stroke of the pump. At or
about the centre of the working barrel and in its upper part we make a
transverse opening communicating without the intervention of any
valve with the pan, condenser, or other vessel from which vapour is to
be exhausted. We also arrange inlet and outlet valves at each end of
the working barrel, and by preference we make the chambers at each
end of the barrel of such a capacity that when the piston is withdrawn
to the end of its stroke the water or other lubricant in the pump barrel
may fill only the lower half of the working barrel at that end, while as
the piston advances on its instroke the water or other lubricant rises,
until eventually it forces out all vapour or air before it, and a small
quantity passes out at the outlet valve, and we take care to arrange all
surfaces in such a way that the air or vapour and the water or other
lubricant are guided to this outlet valve. This outlet valve we construct
with a hollow conical lower part projecting down below the valve
seating into the pump, so that from its conical form it aids to guide the
vapour and water to the outlet formed around it, when it rises at the
same time, that being hollow it has a certain tendency to float in
the water or other lubricant, and is thus more easily opened, and to that
extent the piston of the pump is relieved of pressure; we allow its edges
to bed upon a thick pad of soft india-rubber.
We keep up the supply of the water or other lubricant so that there
may always be a sufficient supply to allow a little to be forced out at
each outlet valve at each stroke by cutting grooves into the upper part
of the working barrel on each side of the central opening already.
described, and connecting these grooves by means of a pipe with water.
or other lubricant contained in a receptacle in the open air. This
receptacle may in some cases be placed at a considerable elevation above
the
pump, so that the water or other lubricant may force its way into.
the pump under greater pressure, or the supply of lubricant may be
obtained from the receptacle in which it is contained after being pumped
through the outlet valve.
It is obvious that when the piston is at either end of its stroke the

page_text: :
cation with the pan, condenser, or other vessel to be exhausted. Let us
suppose the piston to be at the front end of its stroke, and describe the
condition of the pump and what occurs as it passes from the front to
the back end of the barrel. The piston being at the back end of the
barrel the water in the chamber at this end will have filled the chamber
been forced up to and out through the outlet valve; the inlet valve
will be closed, and the groove for admitting water on the front side of
the central opening will be covered by the long piston, and any water
forced into the pump along this groove by the pressure of the atmosphere
on the water in the receptacle from which it is supplied will have to
work its way slowly around the piston to the back end of the barrel.
At the back end the water will only half fill the barrel, the outlet valve
will be closed, the inlet valve just closing, because the pump barrel is in
direct communication with the vessel to be exhausted by means of the
central opening, and the groove for admitting water at the back end of
the barrel will be running freely, since the water will be forced into it
by the pressure of the atmosphere. As the piston begins to move the
outlet valve at the front end of the pump will close next the inlet valve
at the front, and will usually open; then the long piston will gradually
close the central opening referred to, and as it advances will raise the
level of the water at the back end of the pump; the inlet valve will
close (if this be weighted or closed by a spring it will close almost before
the piston moves towards it); next the piston will pass across the groove
admitting water to the back end of the pump, and the water thus
admitted around the piston being under the normal pressure of the
atmosphere will form an efficient packing for the piston until the general
level of the water at this end has risen above the top of the working
barrel; then the air or vapour driven before the rising water will open
the outlet valve and escape, and be followed by a small quantity of
water. As the piston advances it will be evident that a more or less
perfect vacuum will be formed at the front end of the pump, and if the
tension of air or vapour in the vessel to be exhausted is sufficient to open
the inlet valve the barrel will gradually fill with this air or vapour,
which however will be more attenuated to the extent of the force neces-
sary to open the valve than that in the vessel itself. As however the
piston nears the end of its stroke the central opening becomes uncovered,
and then the front end of the barrel being put into direct communi-
cation with the vessel to be exhausted becomes filled with air or vapour
of the same tension as that it contains. This is again expelled on the
-

page_text: return stroke.
This arrangement, though chiefly useful for vacuum
pans, may also be employed for other purposes, as for instance for the
air pump of a condensing engine.
For the sake of economizing space we prefer to drive the vacuum
pump from the steam cylinder by means of what is known as a slot
frame motion. In this the crank shaft is half way between the steam
cylinder and the pump, the crank pin itself working in brasses free to
move up or down vertically in a slot at right angles to the course of the
piston rod.
In a vacuum pump much work at the end of the stroke must be done
by the fly wheel unless full steam be carried to the end of the stroke,
and thus a considerable strain would be thrown upon this slot frame;
and as this motion is ordinarily arranged this strain would be thrown
upon the frame not directly in the line of the thrust of the piston rod,
but at some distance above or below this, thus causing a cross strain
very likely to injure the rod. To avoid this evil we make use of two
cranks, crank shafts, and fly wheels, one on each side of the piston
rod.
We arrange the cranks of these two crank shafts directly opposite to
one another, and we arrange so that the crank pin of each with its
bearing passes only half way through the slotted frame, consequently the
two crank pins can pass one another in the slot frame. We arrange
that these two crank shafts with their fly wheels shall revolve in opposite
directions.
We fit each of the fly wheels with an apparatus which effectually
prevents it from revolving in any but its proper direction, the conse-
quence of this is that one of the crank pins is always exactly as much
above the centre of the piston rod as the other is below it, and as the
two fly wheels absorb or give out power simultaneously the pressure at
a point above the centre line of the piston thrust is always counter-
balanced by an equal pressure at a similar point below it, and so the
objectionable cross strain is avoided. This arrangement is applicable
to the driving of other pumps as well as vacuum pumps.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alfred Fryer and James Bingham Alliott in the
Great Seal Patent Office on the 16th June 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ALFRED
FRYER, of Wilmslow, in the County of Chester, and JAMES BINGHAM
ALLIOTT, of Radford, in the County of Nottingham, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of December, in the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto we, the said Alfred Fryer and James
Bingham Alliott, Her special license that we, the said Alfred Fryer and
James Bingham Alliott, our executors, administrators, and assigns, or
such others as we, the said Alfred Fryer and James Bingham Alliott, our
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF VACUUM PANS, AND IN THE CONSTRUCTION
OF AND MODE OF DRIVING VACUUM PUMPS TO BE EMPLOYED THEREWITH, PARTS OF
WHICH IMPROVEMENTS ARE ALSO APPLICABLE FOR OTHER PUMPS," upon the con-
dition (amongst others) that we, the said Alfred Fryer and James
Bingham Alliott, our executors or administrators, by an instrument in
writing under our, or one of our, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Alfred Fryer (on behalf of myself
and the said James Bingham Alliott) do hereby declare the nature of
the said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following
statement and accompanying Drawings:-
Our improvements in vacuum pans consist in improved methods of

page_text: forming the lower part of the pan and inserting the heating tubes. At
present the interior heating surfaces are usually composed either of
spiral worms through which steam circulates, or of straight tubes
arranged much as in a multitubular boiler, the liquid to be evaporated
occupying the inside of these tubes, which are surrounded and heated
by steam. In either case should a leak occur in any of the tubes almost
the whole of the pan must be pulled to pieces, and usually the joints of
all the air and steam pipes connected with it must be broken in order to
remove the damaged part for repair, and thus any repair is costly in
money, and still more costly in time, trouble, and annoyance.
Our improved vacuum pan is represented in side elevation at Fig. 1
in the annexed Drawing, in vertical section at Fig. 2, and in horizontal
section at Fig. 3. It is made with a bottom a, a, formed by preference
of cast metal, either brass or iron being usually employed. The
bottom a, a, may, if desired, be partially jacketed with steam, as at b, b,
and in this case the steam jacket may be cast on to the bottom. On the
sides of the pan at varying heights and on different sides thereof we
form a number of plane surfaces of equal size, which we prefer to makė
vertical, or nearly so. In these plane surfaces we form openings d, d,
which are closed by covers e, e, bolted on to them. Into each of these
covers we insert a coil, serpentine, or grid f, f, of heating tubes, which
is attached at one end to a steam pipe 9, 9, while at its other end is an
outlet pipe h, h, for any water which may be condensed in it. As there
are several of these grids or serpentines in each pan, and as each grid or
serpentine with the cover to which it is attached may be like every other
grid or serpentine, with its cover belonging to the same pan, by pro-
viding a single spare serpentine and cover it is easy at any time (if a leak
should occur in one of the serpentines) to stop the pan, remove the
leaky serpentine without pulling the pan itself to pieces, replace it by
the sound spare serpentine, and after a very short delay get the pan to
work again, while the damaged part can be repaired at leisure. Instead
of each of these grids being attached to its cover it may be connected
to a steam inlet and a condensed water outlet attached to the opposite
side of the pan, and yet be easily accessible and removable when the
cover is taken away..
If all the serpentines were put in on the same side of the pan they
could not be placed close above one another, but by placing every
alternate serpentine on another side or facet of the pan (see plan view,

page_text: -
Vacuum pumps as at present usually made are unable, even theo-
retically, to produce a perfect vacuum, because the valves by means of
which the air or vapor to be exhausted enters the pump require some
power to open them, and thus air or vapour in a very attenuated state
could never get into the pump at all. In order to remedy this defect we
construct a pump of which we prefer to make the working barrel
horizontal.
Fig. 4, Sheet 2, in the annexed Drawings is a transverse section, and
Fig. 5 a longitudinal section of our improved vacuum pump. The
working barrel A, A', we make about double the length of the stroke of
the piston B of the pump, while we prefer to make the piston B itself
nearly, but not quite, the length of the stroke of the pump. At or
about the centre of the working barrel A and in its upper part we make
a transverse opening C communicating by means of a passage D without
the intervention of any valve with the pan, condenser, or other vessel
from which vapour is to be exhausted. We also arrange auxiliary inlet
valves G and outlet valves H at each end of the working barrel A, A³,
and by preference we make the chambers A", A, at each end of the
barrel of such a capacity that when the piston B is withdrawn to the end
of its stroke the water or other lubricant in the pump barrel may fill
only the lower half of the working barrel at that end (see right side of
Fig. 5), while as the piston advances on its instroke the water or other
lubricant rises until eventually it forces out all vapour or air before it,
and a small quantity passes out at the outlet valve H, so that the
chamber is completely filled with water, as shown at the left hand in
Fig. 5, and we take care to arrange all surfaces in such a way that the
air or vapour and the water or other lubricant are guided to this outlet
valve. This outlet valve H we construct with a hollow conical lower
part projecting down below the valve seating into the pump, so that
from its conical form it aids to guide the vapour and water to the outlet
formed around it, when it rises at the same time; that being hollow, it
has a certain tendency to float in the water or other lubricant, and is
thus more easily opened, and to that extent the piston B of the pump is
relieved of pressure. We allow its edges to bed upon a thick pad of
'soft india-rubber h, h.

page_text: We keep up the supply of the water or other lubricant so that there
may always be a sufficient supply to allow a little to be forced out at
each outlet valve at each stroke by cutting grooves I, I, into the upper
part of the working barrel on each side of the central opening C, already
described, and connecting these grooves by means of a pipe J with water
or other lubricant contained in a receptacle in the open air. This recep-
tacle may in some cases be placed at a considerable elevation above the
pump, so that the water or other lubricant may force its way into the
pump under greater pressure; or the supply of lubricant may be obtained
from the receptacle in which it is contained after being pumped through
the outlet valve.
It is obvious that when the piston B is at either end of its stroke the
central opening C will by means of the passage D put the pump barrel
into direct communication with the pan, condenser, or other vessel to be
exhausted. Let us suppose the piston to be at the front end of its
stroke, and describe the condition of the pump and what occurs as it
passes from the front to the back end of the barrel. The piston B being
at the front end of the barrel A', the water in the chamber A¹¹¹ at this
end will have filled the chamber and been forced up to and out through
the outlet valve H; the inlet valve G₁ will be closed, and the groove I¹
for admitting water on the front side of the central opening C will be
covered by the long piston B, and any water forced into the pump along
the groove by the pressure of the atmosphere on the water in the rep-
tacle from which it is supplied will have to work its way slowly around
the piston B to the back end of the barrel A. At the back end the
water will only half fill the barrel, the outlet valve H will be closed, the
inlet valve G just closing, because the pump barrel A is in direct com-
munication with the vessel to be exhausted by means of the central
opening, and the groove I for admitting water at the back end of the
barrel will be running freely, since the water will be forced into it by
the pressure of the atmosphere. As the piston B begins to move, the
outlet valve H¹ at the front end of the pump will close first, next the
inlet valve G¹ at the front end will usually open, then the long piston B
will gradually close the central opening C referred to, and as it advances
will raise the level of the water at the back end of the pump, the inlet
valve G will close (if this be weighted or closed by a spring it will close
almost before the piston moves towards it), next the piston B will pass
across the groove I, admitting water to the back end of the pump, and

page_text: the water thus admitted around the piston B being under the normal
pressure of the atmosphere will form an efficient packing for the
piston B until the general level of the water at this end has risen above
the top of the working barrel A, then the air or vapour driven before
the rising water will open the outlet valve H and escape, and be followed
by a small quantity of water, the pump being now in the position shown
at Fig. 5. As the piston B advances it will be evident that a more or
less perfect vacuum will be formed at the front end A¹ of the pump, and
if the tension of air or vapour in the vessel to be exhausted is sufficient
to open the inlet valve G¹, the barrel will gradually fill with this air or
vapour, which however will be more attenuated to the extent of the
force necessary to open the valve G¹ than that in the vessel itself. As
however the piston B nears the end of the stroke the central opening C
becomes uncovered, and then the front end of the barrel A¹ being put
into direct communication with the vessel to be exhausted becomes
filled with air or vapour of the same tension as that contained in the
latter. This is again expelled on the return stroke. This arrangement,
though chiefly useful for vacuum pans, may also be employed for other
purposes, as, for instance, for the air pump of a condensing engine.
For the sake of economizing space we prefer to drive the vacuum
pump from the steam cylinder by means of what is known as a slot
frame motion. In the ordinary arrangement of this motion the crank
shaft is half way between the steam cylinder and the pump, the crank
pin itself working in brasses free to move up or down vertically in a slot
at right angles to the course of the piston rod.
In a vacuum pump much work at the end of the stroke must be done
by the fly wheel unless full steam be carried to the end of the stroke,
and thus a considerable strain would be thrown upon this slot frame, and
as this motion is ordinarily arranged, this strain would be thrown upon
the frame, not directly in the line of the thrust of the piston rod, but at
some distance above or below this, thus causing a cross strain very
likely to injure the rod. To avoid this evil we make use of two cranks,
crank shafts, and fly wheels, one on each side of the piston rod.
On Sheet 3 of the Drawings Fig. 6 is an elevation (with the front fly
wheel removed), and Fig. 7 a plan view of a pump driven according to
our improved system. O represents the framing or bed plate, to which
the pump P and steam engine cylinders Q are fixed; R is the slot
frame coupling the piston rods of the pump and engine.
";

page_text: We arrange the cranks K and L of these two crank shafts U and V
directly opposite to one another, so that the crank pin S or T of each
with its bearing passes only half way through the slotted frame R, con-
sequently the two crank pins can pass one another in the slot frame, as
shown in section at Fig. 7. We arrange that these two crank shafts
with their fly wheels W and X sball revolve in opposite directions, as
shown by the arrows.
We fit each of the fly wheels W, X, with an apparatus Y (shewn in
Figs. 6 & 7 applied to the fly wheel X only), which effectually prevents
it from revolving in any but its proper direction. The consequence of
this is that one of the crank pins is always exactly as much above the
centre of the piston rod as the other is below it (see Fig. 6), and as.
the two fly wheels W, X, absorb or give out power simultaneously tho
pressure at a point above the centre line of the piston thrust is always
counterbalanced by an equal pressure at a similar point below it, and so
the objectionable cross strain is avoided. This arrangement is appli-
cable to the driving of other pumps as well as vacuum pumps.
Having now described the nature and object of our said Invention,
together with the manner in which the same is to be or may be per-
formed or carried into practical effect, we wish it to be understood that
we claim as our Invention,-
First. The construction of a vacuum pan, substantially as described.
Secondly. The mode of heating a vacuum pan by means of several
similar and easily removable serpentines or grids of heating tubes, sub-
stantially as described. .
Thirdly. The arrangement of plane surfaces at different heights on and
(if desired) on different sides of the lower portion of the pan for receiving
easily removable serpentines or grids of heating tubes, substantially as
described.
Fourthly. The general construction of a vacuum pump, substantially
as described.
Fifthly. The provision of an opening or openings in the working
barrel of a vacuum pump at or near its centre for putting the front end
of the barrel into direct communication, without the intervention of any
valve, with the vessel to be exhausted when the piston is at the back

page_text: end of the stroke, and the back end of the barrel into direct communi-
cation with the said vessel when the piston is at the front end of its
stroke, all substantially as described.
Sixthly. The provision of a central opening, as above described (in
claim 5), combined with the use of a piston less than half the length 5
of the working barrel, that is, not quite half the stroke of the pump in
length.
Sevently. The arrangement of grooves, substantially as described,
connected with a supply of water or other lubricant forced into the
pump under atmospheric or other pressure for the purpose of packing 1
the piston and preventing leakage of air or vapour past it.
Eighthly. The use of auxiliary air inlet valves, substantially as
described, in connection with the central opening into the pump barrel
without the intervention of a valve.
Ninthely. Making the outlet valve of conical shape below and hollow,
substantially as and for the purposes described.
Tenthly. The use of two crank shafts (with their fly wheels) revolving
in opposite directions, but both having their crank pins working in the
same slotted frame, in connection with and interposed between the piston
rods of a driving or steam cylinder, and of a driven cylinder or pump,
for the purpose of equalizing the strains in such slotted frame, all sub-
stantially as described.
In witness whereof, I, the said Alfred Fryer (on behalf of myself
and the said James Bingham Alliott), have hereunto set my
hand and seal, this Thirteenth day of June, in the year of our
Lord One thousand eight hundred and seventy-six.
]