IMPROVEMENTS IN; AND RELATING TO DUST COLLECTORS FOR MILLS WAREHOUSES AND INDUSTRIAL WORKS
Year: 1883

page_text: LETTERS PATENT to Pieter Van Gelder of Sowerby Bridge in the County
of York Milling Engineer for an Invention of "IMPROVEMENTS IN; AND
RELATING TO DUST COLLECTORS FOR MILLS WAREHOUSES AND INDUSTRIAL
WORKS
PROVISIONAL SPECIFICATION left by the said Pieter Van Gelder ät the
Office of the Commissioners of Patents on the 20th October 1883.
PIETER VAN GELDER of Sowerby Bridge in the County of York Milling
Engineer "IMPROVEMENTS IN AND RELATING TO DUST COLLECTORS FOR MILLS,
WAREHOUSES, AND INDUSTRIAL WORKS"
The specification of my patent N° 561 of 1882 differs from all previous ones
that I have seen, among other things in that it specifies bringing a contrary current
of clean air through the filter while it is being shook and when the regular
current has been cut off. Now I have found this invention very successful but
capable of being improved and it is to add these improvements that this my present
application is designed.
"
I find that it is very desirable for the filter to have a quiet moment between the
time when the regular current is cut off, and that when the reverse current enters,
as otherwise when the motion gets slack both currents will be on at once with the
result of more firmly fixing. the fibres of stive to the filter cloth. I propose
accordingly to place a second cam and levers to work the contrary. currents
independent of the cam and levers that work the ordinary-current, but working
synchronously with them,
I find too that while ordinary air acts very well in very dry and warm countries,
in Great Britain the return current should be dried or heated, I therefore use a hot
air stove to heat the reverse current and a fan to force it in and connect all the
valves of the filter for admitting the return current, with a valve between the hot
air stove and the fan for forcing it in. In consequence of this connection, it is
only when a valve is open into a filter for the passage of the return current that
the hot air pipes of the stove have communication with the fan, and thus no hot
air is blown to waste, and during the time that all the filters are filtering, the hot

page_text: air stove is not having heat extracted by the passage of air through its circulating
or zig zag heating pipes. It is well known that wool or silk are bad conductors of
magnetism or electricity but good retainers, especially when damp, and I believe
that some resinous electricity is produced by the friction of the air passing with
great speed through the meshes of the filter. It is also known that electricity will
attract small pieces of fibre, such as pieces of paper and pieces of bran etcetera. I
have found that it takes three or four months working before sufficient attractive
power is collected in the filter so as to make it retain those small fibres. When
advanced so far neither the shaking nor the backblast are able to remove those
particles from the filter.
I also have observed that when a powerful current passes through the filter, the
two opposite sides of the filter surface are drawn or pressed together. This happens
as well in my collector as in others. It is clear when this happens that the greater
part of the filter surface is useless. To remedy this, I put between the two sides a
brass or copper wire cage,-which allows the filter to be pressed against its sides
and yet gives room for the air to pass through it. The application of this cage
will enable me to make filters of any desired size. Besides it serves another
purpose.
If my observation about the collection of some attractive power in the filter be
correct, then the filter coming frequently in contact with the copper wire (which is
a good conductor and is joined to the iron rings and further with the other
mechanism of the machine) will prevent the collection of attractive power in the
filter.
Furthermore the preliminary box marked B in the specification and drawings of
my aforesaid patent, though formed of very porous materials is apt to have its
filtering sides clogged up with stive, I therefore propose to make its sides of flexible
cloth not stretched tight but somewhat baggy and arrange the mechanism so that
occasionally the current shall stop or in practice be reversed. This causes the
bulging of the sides to also be reversed, and as in flipping a towel or duster the
dust upon it is apt to be shook out, so with the flapping of the sides of the box the
dirt falls off onto the bottom, and is worked out by the screws.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Pieter van Gelder in the Patent Office on the 19th April 1884.
PIETER VAN GELDER, of Sowerby Bridge, in the County of York, Milling
Engineer "IMPROVEMENTS IN AND RELATING TO DUST-COLLECTORS FOR MILLS,
WAREHOUSES, AND INDUSTRIAL WORKS."
This invention being a series of improvements on my patent of 1882 (N° 561) I
will describe the complete apparatus with my improvements, and then afterward
specify the novel parts.
The dust which arises in mills and other places such as warehouses and industrial
works is not merely a serious nuisance but is sometimes a danger as it is apt to
form an explosive mixture with the air.
In coal mines it is found that air laden with dust will explode with a much
smaller percentage of gas than air not dust laden..

page_text: in your customary to bring wit vaunuol
machines to a special stive room.
will
Now my invention while particularly designed to supersede that stive room,
also be found of great value in warehouses and industrial works where dust laden
air is required to be purified.
The invention will be best understood by reference to the accompanying sheets
of drawings which illustrate the improvements as applied to a flour mill in place of
the above-mentioned stive-room.
Fig 1 is an elevation partly in section of the apparatus,
Fig 2 a plan of same.
Fig 3 an enlarged elevation partly in section of mechanism for actuating filters
and valves hereafter described.
Fig 4 plan of same.
Figs 5 and 6 sectional views of valves shewing their position when in use.
Fig 7 a plan of valve.
Fig 8 an enlarged part elevation and part section shewing construction of filter.
Fig 9 a part plan of means for supporting the filtering cloth material.
Fig 10 an enlarged part sectional elevation of filter on line aa Fig 9.
Fig 11 a part section enlarged of outlet valve.
Fig 12 an enlarged detail of filter.
The invention consists in an air filtering apparatus so arranged that the currents
of air to be purified shall bend sharply round, allowing the larger particles to
separate by their impetus and causing the dusty air to pass through corrugated or
other air filters A of any ordinary or desired construction enclosed within the
boxes K, armed with shaking or knocking mechanism, the drawings show a shaking
mechanism. The filter I have found by experiment to work the best is that shown
in the drawings, and is constructed as follows. To the metal rings a a¹ aª a³
Figs 8 and 9 are attached or fixed (either by screw aª as shewn at Fig 9, or by any
other convenient means) an equal number of spokes or bars a³ aº. The spokes or
tension bars as being by preference (though not necessarily so) made of wood and
of tapered form as shewn, while the upper spokes a³ are of round iron, these may
in some cases be of wood but I prefer for lightness of construction strength and
durability to make them of round iron bars. The filtering cloth B is cut into short
lengths, the end a' being nailed to the side of one of the spokes or bars a, and
then carried over the round bar a³ and down to a second bar a where it is nailed
fast at a³; this is repeated with succeeding pieces of cloth until both sides of each
spoke or bar a has a piece of cloth attached to it thus forming a corrugated filter
as shewn at Figs 1, 3 and 8. Between each corrugation is inserted an end-piece b
shewn enlarged at Fig 12, and in position at Figs 3 and 8. In order to prevent the
two opposite sides of the corrugated cloth coming together as shewn at a³ in dotted
lines Fig 8, I insert the brass or copper wire cage C secured to the spokes a®. It
will be readily understood that if a powerful current force the two sides of the filter
together, a large surface of the latter is rendered useless, but by inserting the cage C
the opposite surfaces of the filtering cloth B are prevented from pressing against
each other, but press against the cage instead; room is thus allowed for the air to
pass away through the bars of the cage from both sides. Several (an indefinite
number) of these filters are superimposed as shown, and are preferably connected to
the same entrance and exit passages D and E. Through these filters A the air
passes in an upward direction..
Below the filtering surface is a revolving curved scraper F, which, travelling
round on the floor under the filter, pushes the dust out through the side hole G
into the spout H leading to the box or accumulator I. This curved scraper Fis
formed of a blade of india-rubber so secured to the iron bar / that it can be readily
adjusted. Motion is imparted to it by bevel gearing J through shaft J. The side
hole G is provided with a hinged wedged shaped valve g (shewn in dotted lines at
Fig 10 and also in section at Fig 11) so arranged that it will easily open or close
according to the direction of the blast,⠀

page_text: In course of time the filters A, the sides of which are preferably made of silk
or flannel, become clogged and will no longer act efficiently, the mechanism shown
in Figs 3 and 4 is therefore used. This mechanism consists of a series of chain
wheels T made to revolve by chain gearing, each of these in turn actuates a
worm U on shaft Y', which, gearing into a worm wheel formed on cam-plate V,
causes the latter to revolve. As this cam-plate V revolves the small roller moves
the lever W, thereby conveying motion through rods e* and d, shewn broken off
to the inlet and outlet valves L and M, the rods d and being attached to the
valves at and m Figs 5 and 6; soon after this the lever w brings the clutches X
into connection and motion is communicated to the tappet wheels 6¹ and c, causing
them to revolve and alternately elevate and depress the pivoted levers d and e
These levers actuate two rods, that is, the lever & actuates the rod d¹, and the
lever e actuates the rods e¹ these rods being attached to a ring a10 in the bottom of
the filter A, as shewn at Figs 3 and 4. The suspension rod gll is employed for
holding the upper portion of the filter during the shaking operation, and when the
lower portion of the filter comes in contact with the pin g¹ it lifts the filter so as
to shake the portion b. Whilst the arrangement just described for shaking the
filter gives very good results in small filters, I have found by further.experiments
that it is better especially in larger filters to prolong the levers & and s to the
position shewn at Figs 9 and 10. In this arrangement the intermediate ring alo
can be dispensed with and the rods d' e¹ and g passed through brackets g and g³
fixed respectively to the rings a and a³ as shewn in the drawings. The rods d'
and e' support the brackets g by the nut and check nuts g' and a movable boss g³
is also provided on the rods (in place of pin gl Fig 3) for raising the upper portion
of the filter. The rods g¹¹ are attached to the brackets g³ also by check nuts gº.
By this means I am enabled to adjust the filter to any desired height. Rubber
washers may be inserted at g' and g³ to deaden the noise, and to cushion the shaking
movement. In very large filters several rings a' could be used at different heights,
each supported on a nut on rod g, and each having a stop g to shake them as d
or e rises. To effect the clearance of the filter the chain wheels T are set in motion
by a continuous chain S turning in and out among them, or preferably a wheel on
each axle is driven by a chain from the wheel on the axis immediately below, or by
the continuous chain S working in each of these wheels, and through the inter-
mediation of these wheels the rods d³ and e* are set in motion as above described.
As the rods and e³ are actuated, they bring the entrance and exit valves Land M
to the position shown in Figs 5 and 6 that is the valve L is closed to the entrance
of any more dusty air, and the valve M is brought against the seating m¹ the
opening m is then uncovered and allows the entrance of heated air from the
fans N.
I find that it is very desirable for the filter to have a quiet moment between the
time when the regular current is cut off, and that when the reverse current enters,
for allowing the dust to settle, as otherwise when the motion geta slack both
currents will be on at once with the result of more firmly fixing the fibres of stive
to the filter cloth, I therefore arrange the rods working the valves with more play
on the rod working the valve that admits hot air and gives out the purified air
than on the valve that admits the dusty air. The consequence is that the dusty
air admission valve is closed at the first movement of the rods, and not till it is
closed is the hot air valve opened, and the hot air valve is again closed in the
return motion before the dusty air valve is opened. I place a second cam w³ (on
the cam plate V) for conveying motion to the clutch ✗ through lever wand
runner windependently of the cam and lever that works the ordinary currents.
The two cams are so timed that there shall be a few seconds between being
respectively brought into operation. This time enables both valves to be practically
closed at the same time, the valve M is opened the first and allows a small portion
of hot air to pass through the nearly closed valve into the spout or pipe E thus
drying any moisture that may have collected in the spout or exhaust fan P. Only
when the outer valves are entirely closed and the pressure has equalised itself is

page_text: the shaking gear set in motion. The shaking gear is disconnected first and is
entirely at rest before the valves open, and again a small quantity of hot air
is allowed to pass through for the purposes hereinbefore described. .
I find that while ordinary air acts very well in very dry and hot countries in
places where a more moist atmosphere prevails the return current should be dried
or heated, I therefore use a hot air stove O composed of a chamber fitted with
zig-zag steam-pipes o to beat the return current and the fans N to force it in and
connect all the valves M of the filter for admitting the return current, by means of
a chain with a valve o¹ between the hot air stove O and the fan N for forcing it in.
In consequence of this connection it is only when a valve is open into a filter for
the passage of the return current that the hot air of the stove has connection with
the fan, and thus no hot air is blown to waste, and during the time that all the
filters are filtering the hot air stove O is not having heat extracted by the passage
of air through its circulating or zig-zag heating pipes o. It is well known that
wool or silk are bad conductors of magnetism but good retainers especially when
damp, and I believe that some resinous electricity is produced by the friction of the
air passing with great speed through the meshes of the filter.
It is also known that electricity will attract small pieces of fibres such as pieces
of paper and pieces of bran etcetera.
I have found that it takes three or four months working before sufficient:
attractive power is collected in the filter as to make it retain these small fibres.
When advanced so far neither the shaking nor the back blast are able to remove
those particles from the filter.
Now if my observation about the collection of some attractive power in the filter
be correct, then the filter cloth coming frequently in contact with the copper or
brass wire cage C which is a good conductor and is electrically joined or connected
in any convenient manner with the iron rings a, a' a² a³ and further with the
other mechanism of the machine, will prevent the collection of attractive power.in
the filter.
The clean air traversing through the filters in a direction opposite to that taken
by the dusty air clears the filters of the adhering matter. In this it is aided by
the rods del which raise and lower the bottom of the filter thus shaking and
cleaning the interstices of the filtering surface. This return current now laden.
with any particles it may have collected passes out of the filter into the spout H
through side hole G down into the box or accumulator L. This box I is constructed
with sides i formed of very porous flexible cloth (not stretched tight but somewhat
baggy,) attached to the framework i³, and so arranged that as each return current
passes into the box I the sides bulge out in the manner shewn by dotted lines i³.
When the valves are reversed then the sides are drawn inwards, and as in
flipping a towel or duster the dust upon its sides is shaken out, so with the
flapping of the sides of the box, the dirt falls onto the bottom and is worked out
by the archimedean screws . The lower portion of the tube or conducting
spout is by preference (though not necessarily so) made of flexible cloth and
weighted by the wooden flange so as to be capable of contracting and expanding
with the flexible sides i of the box. In some machines I have manufactured in
Great Britain I have made both the sides of the box and also those of the
conducting spout of rigid material, but I find by having them flexible they are not
so soon choked with stive.
In order to make the pressure of air uniform, the exhaust fan P and the fans (if
employed) causing the dusty air to enter the apparatus are so regulated that there
shall be almost exactly the same barometric pressure on both sides of the filter A
notwithstanding the friction of the dust laden air against the pipes or passages and
the filter. This is done by making the exhaust fan the more powerful whether the
entrance fans be special or simply part of the machine producing the dust.
The mode of action is as follows: The dusty air is brought to the apparatus by
means of passage or tube Q connected with spout or tube D, the coarsest and
heaviest particles fall to the bottom (being conducted away through the contracted

page_text: spout or tube g) whilst the lighter particles and dust laden air päss into the filter
through numerous inlet valves L then into the air passages R from whence they
descend into the filter A through a central tube or sleeve r, and by this means the
air is made to pass up through the corrugations of the filter cloth, the dust or other
matter in the air adheres to the outside of the filter cloth whilst the purified air
passes out of each filter through orifices in that portion of the passage R beyond
the partition, thence through exit valve M into spout or tube E being drawn
thereto and from by exhaust fan P. As the dust or other matter accumulates on
the outside of the filter it drops off into the bottom from whence it is removed by
scraper F into spout H and conveyed therefrom as herein before described.
When a filter requires cleaning it is effected by means of the chain wheels T and
their mechanism as herein described which are so arranged that only one filter can
be operated for cleaning at one time and when large numbers of filters are used the
mechanism is so regulated that the moment one filter is thrown into work the next
in course is thrown out for cleaning. By this means the filtering is made uniform,
whereas in all other machines for this purpose that I know of a larger portion of
the filtering surface is periodically thrown out for cleaning and consequently the
working of the machine is made inefficient and irregular. In the drawings at
Fig 1 I have shown filter marked A' as being cleaned as described whilst the
remaining filters are removing the dust from the air.
Having now described the apparatus with all its latest improvements I wish it
to be understood that I make no claim under this patent for those matters set forth
in my Specification N° 561 of 1882 but what I believe to be new and claim under
the present application are:-
Those improvements upon and additions to my said patent of 1882 which are
herein described and the nature of which are set forth in my provisional
Specification and in particular manner the following:―
1st. The arrangement of a quiet time between the moment when the regular
current is cut off and when the reverse current enters, and also the apparatus for
effecting same.
2nd. The application of a return current of heated air and the apparatus for
heating and applying same for the purposes described. 3rd. The application of
metallic skeleton cages inside the filter, substantially as and for the purposes
described.
In witness whereof I the said Pieter van Gelder have hereunto set my hand
and seal this sixteenth day of April in the year of our Lord 1884.
P VAN GELDER (L.s.)