Improvements in and relating to Coffee Making Machines.
Year: 1891

page_text: Date of Application, 10th Dec., 1891
Complete Specification Left, 10th Sept., 1992-Accepted, 15th Oct., 1892
PROVISIONAL SPECIFICATION.
Improvements in and relating to Coffee Making Machines.
We, JOHN LIST of 3 St. John's Park, Blackheath, in the County of Kent,
Member of the Institution of Civil Engineers, and WILLIAM BROWNHILL SMITH,
of 31 Queen Street, Glasgow, in the County of Lanark, Silversmith, do hereby
declare the nature of our said invention to be as follows:-
22
This invention has reference to and comprises certain improvements in the coffee
making machines of the "Napier class and particularly that of the Patent
granted to John List No. 10576 July 8 1890, and the filtering vessel and appliances
and fittings of such machines, which will enable them to produce an infusion of
perfectly clear coffee which does not hold sediment or fine " grounds" in
suspension.
The improvements have reference to and consist, first, in forming the portable
metal strainer attached to the lower end of the siphon drawing off pipe within the
infusion and filtering vessel of two separate flat or concave discs which are soldered
or otherwise attached at the periphery to upper and lower rings and at the centre
to upper and lower ferrules which rings and ferrules fit closely together and which
when so fitted together form a hollow strainer similar in external form to that
heretofore used in machines of the "Napier" type. The upper disc consists of
finely perforated sheet metal, preferably supported on and soldered or otherwise
attached to the rim and centre ferrule as well as to radial ribs which connect the
rim with the ferrule and which give rigidity to the disc. The lower disc consists
of a sheet of unperforated metal soldered or otherwise attached to the rim and
centre ferrule, as in the case of the upper disc, it has also a set of ribs across its
upper part, upon which is laid a layer or layers of flannel, muslin, filter paper, or
other suitable filtering material, or this filtering material may be laid on a disc
of openly pierced sheet metal or on a disc of wire gauze carried upon the ribs.
The filtering material. thus forms a diaphragm across the space between the upper
and lower discs when they are fitted together and it is nipped tightly at the centre
between the abutting faces of the ferrules, and at the periphery between the
abutting faces of the rings. Through the centre ferrules the lower end of the
siphon tube passes and it is formed with perforations as described in Patent
No. 10576 of 8 July 1890, the only difference being that these perforations are
entirely below the plane of the filter diaphragm formed of flaune! or other material
and there are corresponding perforations in the centre ferrule of the lower disc
only. The end of the siphon tube is closed by a close bottomed screw nut as
heretofore, this nut holding the upper and lower discs of the strainer firmly
together. If desired bayonet catches or screws or hinged bolts in recesses may
be fitted around the periphery to still more firmly hold the parts together and
nip the filtering material between the rims. In a compound strainer-filter of the
above described construction the infusion of coffee passés first through the strainer
of perforated sheet metal upon which is caught all the coarse sediment or "grounds"
and then through the filter of flannel or other material upon which the fine sediment
is caught, the infusion then passes into the siphon tube clear and free from any
particles of coffee held in suspension. By removing the nut from the end of the
siphon tube the strainer-filter can be detached from it and it can then be
readily taken apart for cleansing and for the renewal of the filtering medium.
A further improvement consists in a modification of the filtering and infusing
vessel and of the siphon tube and filter fitted to this vessel. In the machine
made under Patent No. 10576 July 8 1890 the filtering vessel is portable to

page_text: enable it to be removed for washing out. The siphon tube is also portable. In
this modification the vessel is fixed and stands upon legs or on a wood or metal
rim secured to a bed-plate, preferably the same bed-plate which carries the boiler.
This modified filtering vessel may have a considerably increased ratio of diameter
to height for any given capacity compared with the proportions of the vessels
heretofore in use, the object of this modification being to secure more rapid
filtration. To prevent radiation of heat this mixing vessel may have a portable
metal cover and it may also be lagged with felt, wood or other suitable non-
conducting material. The bottom of the vessel is made dished or concave in form
as heretofore and from the centre of the bottom is carried a radial draw-off pipe
which passes outside the bottom and which may be attached to it by a screwed
joint as in the case of the boiler or by a brazed or soldered joint, or bolted flange,
or other suitable means. This radial pipe is connected to a vertical bent pipe
which passes up outside the infusing vessel and is connected to the double action
cock on the top of the boiler. This fixed vertical pipe connected to the above
described radial draw off pipe. takes the place of the portable siphon pipe formerly
used. To admit of these fixed pipes and the infusing vessel being washed out, a
cock is fitted to the lowest part of the radial draw off pipe. Water can thus be
passed from the double action cock on the top of the boiler through the pipes and
into the vessel and the whole drained out into a bucket. The filter to be used
with the above described infusing vessel is a modified form of the compound
strainer-filter herein before described, it takes in this case however the form of a
circular sieve which can be readily inserted in and removed from the lower part of
the interior of the infusing vessel. This sieve strainer filter consists of an upper
and a lower part. The upper part is formed with an upstanding rim connected
at its lower edge by radial ribs to a small centre boss or circular plate. On these
ribs is laid a disc or it may be a number of radial segments of finely perforated
sheet metal which is soldered or otherwise suitably attached to the upper surface
of these ribs and to the upper surface of the centre boss or plate as well as to a
ledge projecting inwards from the lower part of the upstanding rim. This sieve
or tray is provided with a centre handle or two handles attached to the inside
of the rim, so that it can be readily lifted in or out of the vessel. To the under-
side of this sieve is attached a frame consisting of a shallow metal rim having
radial ribs connecting it with a centre plate similar to that on the sieve strainer.
Through this centre plate of the lower frame passes a screwed bolt which is tapped
into the underside of the centre plate of the sieve and which is formed with a
butterfly head, so that it can easily be screwed up with the fingers and thumb. The
outer rim of the lower frame fits into a grove on the underside of the sieve rim
and is firmly held against it by the pressure of the centre screw, and it may be
by also countersunk screws spaced around the periphery. Between the underside
of the sieve and the upper surface of the lower frame is inserted a disc or discs of
flannel, muslin, filter paper, or other suitable material which lies on the surface
of the ribs of the frame, or it may be on a circular plate of openly pierced
sheet metal, or on a circular sheet of metal gauze carried by the ribs. The
relative positions of the upper surface of the filter and the underside of the metal
strainer are so arranged that there is sufficient space left between them for the
accumulation of fine sediment. The circular sheet or sheets of flannel or other
filtering material is of such a diameter that it projects half an inch or thereby
beyond the joint of the rim of the frame, and rim of the sieve; and the
diameter of the rim of the sieve is so arranged that when the latter is pressed
down into the infusing vessel the projecting rim of flannel or filtering material
is turned up all round and forms practically a tight joint between the outside of
the sieve and the inside of the infusing vessel. The sieve is pushed down until
the frame which is attached to it underneath, rests in a ledge formed around the
periphery of the inside of the bottom of the infusing vessel. In this way a
portable compound strainer filter is fitted in the vessel leaving a shallow space
below it which is in communication with the fixed siphon radial tube to the

page_text: boiler. The infusing, straining, and filtering of the coffee is carried ou exactly
as in the case of a machine with the strainer-filter attached to the portable
siphon pipe. The coarse ". grounds" or sediment is caught upon the strainer and
the fine sediment on the filter. After the coffee is drawn over, the sieve is lifted
out of the vessel with the coarse grounds in it, and the lower frame can then
be readily detached and the whole cleaned and the filter material renewed when
necessary.
A further improvenient connected with this machine having the fixed form of
infusing vessel consists in an arrangement whereby the water used can be boiled
at any desired pressure above that of the atmosphere in the boiling and serving
vessel and from there passed direct to the infusing vessel, the increased tem-
perature due to higher pressure being utilized to heat up the metal of that
vessel together with the metal sieve-strainer filter it contains. For this purpose a
branch pipe and cock is fitted to the lower part of the boiler or it may be
branched off the serving pipe from the boiler bottom. The cock on this new pipe
is connected either to the vertical pipe which connects the double action cock with
the radial draw off pipe on the bottom of the infusing vessel or to this radial draw
off pipe, or it may be direct to the infusing vessel itself. The method of working
the machine with this new connection is as follows.-The boiler is filled by the
double action cock to the desired height with it may be cold water if there is no
.hot water available. This cock is then set to the position "all shut," and the air
cock on the top of the gauge glass is also shut. Steam is then turned on to the
jacket and the water boiled under the pressure to which the safety valve is loaded.
When the safety valve begins to blow off the cock connecting the bottom of the
boiler with the infusing vessel is opened and the high temperature boiling water
passed into the vessel. Before the boiler is emptied of water this cock is shut and
the double-action cock is set to the position marked "drawn off" that is the top
of the boiler is put in communication with the bottom of the infusing vessel. The
steam jacket is still kept in operation and the air is then driven out of the boiler
and of the connecting pipes up through the sieve strainer-filter, and through
the water in the infusing vessel. The dry ground coffee, which may be ground
exceedingly fine, is then thrown into the boiling water in the infusing vessel, and
stirred up and infused for a short time, care being taken not to keep the infusion
boiling in presence of the "grounds "for any length of time as if that is done, the
bitter property of the coffee is extracted and the infusion becomes less palatable.
The infusion is then drawn over into the boiler by atmospheric pressure and the
partial vacuum formed in the boiler in the usual way.
A further improvement consists in inserting a smaller complete portable infusing
vessel, or a smaller sieve-strainer-filter, inside the fixed infusing vessel, and
connecting it by a ground joint or a screwed socket to the inlet of the radial draw
off pipe. By means of this a smaller quantity of coffee can be more easily infused
in a large size machine.
Dated the 9th December 1891.
COMPLETE SPECIFICATION.
Improvements in and relating to Coffee Making Machines.
We, JOHN LIST, of 3 St. John's Park, Blackheath, in the County of Kent,
Member of the Institution of Civil Engineers, and WILLIAM BROWNHILL SMITH
of 31 Queen Street, Glasgow, in the County of Lanark, Silversmith, do hereby
declare the nature of our said invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following

page_text: statement in writing reference being had to the accompanying drawings, that is
to say:
This invention has reference to aud comprises certain improvements in the
coffee making machines of the Napier class and particularly that of the Patent
granted to John List No. 10576 July 8 1890, and the filtering vessel and appliances
and fittings of such machines, which will enable them to produce an infusion
of perfectly clear coffee which does not hold sediment or fine "grounds" in
suspension.
And in order that our said invention and the manner of performing or carrying
the same into effect or practice may be properly understood we have hereunto
appended three sheets of explanatory drawings in which the same reference letters
are used to indicate corresponding parts in all the figures where shown.
Figure 1 on Sheet 1 is a sectional elevation of a steam coffee machine, substan-
tially the same as that described in reference to Figures 1 and 2 of the said
former Patent and having the parts lettered to correspond; but fitted with a new
or improved construction of hollow strainer c attached to the siphon pipe c¹, c²,
within the infusing or filtering vessel C, in accordance with this invention.
Figures 2 and 3 are detached face views from the inside of the upper and lower
improved parts el e² of the filter c as separated at their centre joint e for gripping
the new filter cloth el, as shown in Figure 1.
Figure 4 on Sheet 2 shows an elevation of the boiler B, and its fittings,
corresponding to Figure 1, but showing a modified form of the infusing vessel
and its filter e to e and improved arrangement of tube fittings.
And
Figures 5 and 6 are detached internal views analogous to that shown in Figures 2
and 3 of the upper and lower parts e¹, e, of the filter shown in Figure 4.
Figure 7 on Sheet 3 shows a sectional elevation of a modified simple construction
of the steam coffee machine and the improved pipe fittings, from that shown in
Figure 4, but with the same construction of filter e io e' shown in Figures 4 to 6,
while
Figure 8 on Sheet 3, shows a detached sectional elevation of a modified simple
form of the filter e to e shown in Figures 1 to 3; and
Figure 9 shows sectional views through the two couplings e³e of the lower and
upper parts of the filter e¹, e, shown in Figure 1^.
In Figures 1, 4, and 7, the same reference letters are used as far as possible to
represent the corresponding parts in the Specification of the former Patent, and so
avoid a descriptive repetition of these parts.
Referring first to Figures 1 to 3 on Sheet 1, of these drawings,-The improve-
ments have reference to and consist, first, in forming the portable metal strainer c
described in the Specification of the said former Patent attached to the lower end
of the siphon drawing off pipe c, c², within the infusing and filtering vessel C, of
two separate flat or concave discs e¹, e², which are soldered or otherwise attached
at the periphery to upper and lower jointing checked rings e, e, fitting into each
other and at the centre to upper and lower ferrules, or hollow bosses e³, e, and
which rings and ferrules fit closely together at the centre and when so fitted
together form a hollow strainer similar in external form to that heretofore used in
machines of the Napier type. The upper disc e' consists of finely perforated sheet
metal, preferably supported on and soldered or otherwise attached to the rim at e
and centre ferrule e below the upper filter chamber c and rests on radial ribs ell
which connect the rim with the ferrule and which give rigidity to the outer rim
and disc e'. The lower disc e consists of a sheet of unperforated metal soldered
or otherwise attached to its rim e and centre ferrule e, as in the case of the upper
disc e; it has also a set of ribs e across its upper part, upon which is laid a layer
or layers of flannel, muslin, filter paper, or other suitable filtering material e or
this filtering material may be laid on a disc of openly pierced sheet metal or on a
disc of wire gauze carried upon the ribs e. The filtering material e thus forms a
filtering diaphragm across the space c between the upper and lower discs e¹, e²,

page_text: when they are fitted together, and it is gripped tightly at the centre between the
abutting faces of the ferrules e³, e, and at the periphery between the abutting
faces of the rings e. Through the centre ferrules, et, the lower end of the siphon
tube c¹ passes and it is formed with perforations cas described in Patent
No. 10576 July 8 1890, the only difference being that these perforations are
entirely below the plane of the filter diaphragm "formed of flannel or other
material entering the space c', and there are corresponding perforations in the
centre ferrule e' of the lower disc only. The end of the siphon tube c¹ is closed
by a close bottomed screw nut c" as heretofore, this nut pressing and holding the
upper and lower discs of the strainer firmly together. If desired bayonet catches
or screws or hinged bolts in recesses may be fitted around the periphery to still
more firmly hold the parts together and nip the filtering material between the rims.
In a compound strainer-filter of the above described improved construction the
infusion of coffee passes first through the strainer of the upper chamber c and
perforated sheet metal el upon which is caught all the coarse sediment or "grounds,"
and then through the filter of flannel or other filtering material e upon which the
fine sediment is caught, the infusion then passes into the division below it, and
then through the openings into the siphon tube c¹, clear and free from any
particles of coffee held in suspension and then through the three way cock D¹, D³,
into the boiler B from which it is drawn off by the lower tube and cock B³, all as
indicated by the darts in Figure 1, and as described in the Specification of the said
former Patent. By removing the nut from the end of the siphon tube c' the
strainer filter e, e¹, e, can be detached from it and it can then be readily taken apart
at the joint and filter e" for cleaning and for the renewal of the filtering medium.
Referring to Figures 4 to 6 on Sheet 2, a further improvement consists in a
modification of the filtering and infusing vessel C and of the siphon tube c¹ and
filter fitted to this vessel. In the machine made under Patent No. 10576
July 8 1890 the filtering vessel C is portable to enable it to be removed for
washing out. The siphon tube c' is also portable. In this modification the vessel C
is fixed and stands upon legs or on a wood or metal rim C2 secured to a bed plate A,
preferably the same bed plate which carries the boiler B. This modified filtering
vessel C may have a considerably increased ratio of diameter to height for any
given capacity compared with the proportions of the filtering vessels heretofore in
use, the object of this modification being to secure more rapid filtration.
prevent radiation or loss of heat, this mixing vessel C would preferably have a
portable metal cover C, and it may also be lagged with felt, wood, or other
suitable non-conducting material as shown at C. The bottom C¹ of the vessel C
is mude dished or concave in form as heretofore, and from the centre of the
bottom is carried a radial draw-off branch fand tube f' which passes outside the
bottom and which may be attached to it by a screwed joint as in the case of
the boiler B, or by a brazed or soldered joint, or bolted flange, or other suitable
means. This radial pipe is coupled and connected at f" to a lower part of the
vertical bent or siphon pipe c¹ which in this case passes up outside the infusing
vessel C, and is coupled at c to the double action cock and key D', D³, on the top
of the boiler B. This fixed vertical pipe c' connected to the above described
radial draw off pipe f¹ takes the place of the portable siphon pipe c c³ formerly
used. To admit of these fixed pipes and the infusing vessel being washed out, a
drain cock fis fitted to the lowest part of the radial draw off pipe c'.
can thus be passed from the double action cock D', D', on the top of the boiler B
through the pipes c', f, f, and into the vessel C and the whole drained out into a
bucket. The filter to be used with the above described infusing vessel C is a
modified form of the compound strainer-filter herein before described in reference
to Figures 1 to 3, it takes in this case however the form of a circular horizontal
sieve which can be readily inserted in and removed from the lower part of the
interior of the infusing vessel C. This sieve strainer filter consists of an upper
and a lower part, divided at the filter diaphragm.
In this case the upper
part e, e, of the filter is formed with an upstanding rim e* connected at its lower
To
Water

page_text: .
edge by the radial ribs el to a small centre solid boss or circular plate e³. On
these ribs is laid a disc.el or it may be a number of radial segments, of finely
perforated sheet metal which rests on the upper surface of these ribs e¹¹ and
soldered or attached to the upper surface of the centre boss or plate e³ as well as
to a ledge projecting inwards from the lower part of the upstanding rim e.
This
sieve or tray eel is provided with a centre handle or two handles e" attached to the
inside of the rim e*, so that it can be readily lifted in or out of the vessel C. To
the underside of this sieve e, e', is attached a frame consisting of a shallow metal
rim fitting into the upper one e, and having radial ribs & connecting it with a
centre boss or plate e similar to that e on the sieve strainer but without a lower
plate. Through this centre plate e of the lower frame passes the stem of a hand
screw, which is tapped into the underside of the upper centre plate e* of the
sieve and which is formed with a butterfly head, so that it can easily be screwed
up with the fingers and thumb. The outer rime of the lower frame e, e', e, fits
into a groove on the underside of the upper sieve rim e, e¹ and is firmly held
against it by the pressure of the centre screw e and it may be also by countersunk
screws spaced around the periphery of the rim e. Between the underside of the
sieve e¹ and the upper surface of the lower frame is inserted a disc or discs e¹¹ of
flannel, muslin, filter paper, or other suitable material which lies on the surface of
the ribs e of the lower frame, or it may be on a circular plate of openly pierced
sheet metal, or on a circular sheet of metal gauze carried by these ribs.
The
relative positions of the upper surface of the filter and the underside of the metal
strainer are so arranged that there is sufficient space c left between them for the
accumulation of fine sediment. The circular sheet or sheets of flannel or other
filtering material el is of such a diameter that it projects half an inch or thereby
beyond the joint e of the rims e, e, of the frame, and of the sieve; and the diameter of
the rim of the sieve is so arranged that when the latter is pressed down into the
infusing vessel C, the projecting rim of flaunel or filtering material is turned up
all round and forms practically a tight joint between the outside of the rim ex of
the sieve and the inside of the infusing vessel C. The sieve is pushed down until
the frame which is attached to it underneath, rests on a ledge formed around the
periphery of the inside of the bottom of the infusing vessel C at C*. In this way
a portable compound strainer-filter is fitted in the vessel C leaving a shallow
space below it which is in communication by the branch f, with the fixed
siphon radial tube c', to the boiler B. The infusing, straining, and filtering of the
coffee may be carried on exactly as in the case of a machine with the strainer-
filter attached to the portable siphon pipe c', c², up the centre of the vessel C. The
coarse "grounds" or sediment is caught upon the metal strainer el and the fine
sediment on the filter cloth ell within the space c. After the coffee is drawn over,
the sieve e to 7 is lifted out of the vessel C with the coarser "grounds" in it above
the metal sieve e', and the lower frame e, e, can then be readily detached and the
whole cleaned, and the filter material e renewed when necessary.
A further improvement connected with this arrangement of machine having the
fixed form of infusing vessel C, consists in an arrangement whereby the water used
can be boiled at any desired pressure above that of the atmosphere in the boiling.
and serving vessel B and from there passed direct to the infusing vessel C, the
increased temperature due to higher pressure being utilized to heat up the metal
of that vessel together with the metal sieve-strainer filter it contains. For this
purpose a branch pipe B and cock B is fitted to the lower part of the boiler B.
The cock B on this new pipe B is connected as shown at B6 to the vertical pipe c¹
which connects the double action cock D', D³, with the radial draw off pipe on the
bottom of the infusing vessel C, or the connection may be made to the radial draw
off pipe B². The method of working the machine with this new connection is as
follows: The boiler B is filled by the double action cock D1, D2, to the desired
height with, it may be, cold water, if there is no hot water available. This
cock D¹, D', is then set to the position "all shut," and the air cock at g" on the
top of the gauge glass is also shut. Steam is then turned on to the jacket B",
and

page_text: the water boiled in the boiler B under the pressure to which the safety valve vis
loaded. When the safety valve begins to blow off, the cock B connecting the
hottom of the boiler B with the infusing vessel C is opened and the high
temperature boiling water passed into the vessel C, by the pipe c' and branches ff.
Before the boiler B is emptied of water this cock B is shut, and the double-action
cock D', D, is set to the position marked "draw off," that is, the boiler B is put in
communication with the bottom of the infusing vessel C. The steam jacket B", is
still kept in operation and the air is then driven out of the boiler B, and out of
the connecting pipes cup through the sieve strainer-filter, e to e and through
the water in the infusing vessel C. The dry ground coffee, which may be ground
exceedingly fine, is then thrown into the boiling water in the infusing vessel C, and
stirred up and infused for a short time, care being taken not to keep the infusion
boiling in presence of the "grounds" for any length of time as if that is done the
bitter property of the coffee is extracted and the infusion becomes less palatable.
The infusion is then driven over into the boiler by atmospheric pressure due to the
partial vacuum formed in the boiler in the usual way and as described in the Spec:-
fication of the said former Patent.
Referring to Figure 7 on Sheet 3, this arrangement of steam coffee boiler is
analogous to that shown in Figure 4, except that the boiler B, is raised high
enough on its supports B for the lower discharge branch and cock B to fill the
boiling water from the vessel B direct over the top of and into the infusing
vessel C, instead of using the branch and cock B, B, shown in the former
modification. This vessel C, is constructed with its strainer e to e' in the bottom
substantially as described in reference to Figure 4 and lettered to correspond
except that the lower branch, leads to the lower part of the siphon pipe c¹,
and direct up to the knee and coupling c³, which is here shown as jointed to a
simple branch B' on the top of the boiler B, with the water branch and cock w, w',
directly attached to it, although the branch and coupling c², e, might be coupled to
the three way valve D' D as in the former arrangements Figures 1 and 4. In
this arrangement Figure 7, the water would be filled through the cock w¹ into the
boiler B where it would be boiled as described in reference to the former arrange-
ment Figure 4, and then led through the branch and cock B2 into the infusing
vessel C, always leaving sufficient water in the boiler B to raise steam to pass over
by the tubes 'f' and infuse coffee in the vessel C, and so that when the vacuum
is produced in the vessel B, the coffee will be filtered through the strainer c and
pass up the tubes f¹ c' into the boiler B, and be drawn off into the cups or service
vessels through the same pipe and cock B2 which previously admitted the water
into the infusing vessel C.
Referring to Figures 8 and 9 on Sheet 3, a further improvement consists in using
a smaller complete simple construction of portable sieve-strainer filter formed of
two domed up parts e', e, as shown in Figures 1 to 3, jointed by outer circum-
ferential checked rings e and hollow central eyes or bosses e³, e, in each to grip the
filtering cloth or medium el in the centre joint between them.
The upper
perforated disc part e¹ has its eye e³ fitted loosely on to the lower end of the siphon
pipe and the lower end of this pipe passes into the hollow eye e, so as to secure
the two parts together by bayonet joint grooves f formed in the lower end of the
pipe c', and taking on to pins on the inner side of the lower boss e as seen
more particularly in Figure 9, so as to secure the two parts e' e of the strainer
together by the turning of the tube c¹ and finger flanges f. This strainer would
be placed in the bottom of the fixed vessel C, with its tube c', and the coffee
would be strained through the perforated top disc e' into the upper chamber c and
through the filtering cloth e" into the lower chamber c, and from this would pass
through the holes up the tube c'.
This strainer Figures 8 and may also be fitted on the upper end of a short tube
projecting up from the branch through the bottom of the infusing vessel C, so as
to be suitable for the arrangements shown in Figures 4 and 7. And in this case
the bayonet joint would be formed on the upper end of the short pine projecting

page_text: up from the branch f, instead of on the lower end of the pipe c' as shown in
Figure 8.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is,―
First. In steam heated coffee making machines of the "Napier" class, the
construction and use within the infusing vessel of compound strainers consisting of
discs of perforated and unperforated metal, with annular rings and an intermediate
layer of cloth or other filtering medium interposed between them, substantially as
and for the purposes herein described in reference to and by way of application
shown in the accompanying drawings.
Second. In steam heated coffee making machines of the "Napier" class, the
arrangement and use of a stationary infusing vessel, with drawing-off radial
branch tubes connected to the siphon pipe, substantially as and for the purposes
herein described in reference to and shown in the accompanying drawings.
Third. In steam heated coffee making machines of the "Napier " class, the
arrangement and use of a branch pipe and cock at the lower part of the boiling
vessel for supplying the infusing vessel with heated water, substantially as herein
described in reference to and shown in the accompanying drawings.
Fourth. The general arrangement and combination of the parts of steam heated
coffee making machines of the "Napier" class as fitted with improved constructions
of infusing vessels and their strainers, and supplying and drawing off tubes and
fittings, substantially as and for the purposes herein described in reference to and
shown in the accompanying drawings.
Dated the 9th September 1892.
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.