Improvements relating to the Heating or Drying Cylinders of Paper-drying and like Machines.
Year: 1894

page_text: Date of Application, 2nd Oct., 1894-Accepted, 17th Nov.,, 1894
COMPLETE SPECIFICATION
Improvements relating to the Heating or Drying Cylinders of
Paper-drying and like Machines.
I, ANDREW G. PAUL, of 79 Milk, Street, Boston, County of Suffolk and State
of Massachusetts, United States of America, Engineer, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
The drying cylinders of drying machines consist of hollow cylinders revolving
upon journals of smaller diameter than the cylinders, so that the cavities of the
cylinders extend downward to a lower level than the journals, through which
journals a communication can be had with the cavity of the cylinder.
Heretofore in such drying machines the cylinders have been heated by means of
steam under a pressure above atmospheric pressure and varying from one to
sometimes as much as fifty pounds supplied to each cylinder by means of a pipe
connected with one of the journals thereof. The steam condensed in the cylinders
and as the condensed water bas necessarily to be discharged through the journals
of the cylinders, the water of condensation collected in the lower part of the same.
The presence of this water of condensation in the cylinder interfered with the
operation of the machine and decreased its efficiency, because the water of con-
densation reduced the steam heated or effective drying surface of the cylinder.
The machines have generally been constructed in such a way that the drying of
the paper has been accomplished mainly by the lower part of each of the revolving
cylinders, and as the water of condensation collected in the lower part, it tended to
decrease the effectiveness of their heating surfaces at the very point where they
should be most effective. If this water of condensation should not be removed it
would eventually fill half the cylinder, and so decrease the area of the internal
surface of the cylinder which would be exposed at any one time to the heating
action of the steam that it would be necessary to increase the pressure of the
supply steam so as to convey a larger amount of heat to this exposed surface.
Whenever the water rose in the cylinder to the level of the steam supply opening,
it flowed back into the common steam supply pipe and would have to be discharged
from it in some suitable way. But when this happened the common steam supply
pipe would become partially filled with water and the water would be apt to be
carried into the other cylinders, and the efficiency of the apparatus would be
reduced. Instead of increasing the pressure of the supply steam to counteract the
effect of the collection of the water of condensation, the number of cylinders was
sometimes increased, and this has been done from time to time until now some
machines are made with as many as fifty drying cylinders in order that they may
dry the paper as fast as is desirable.
In order to remove this water of condensation these old machines were in some
cases provided with siphon discharge pipes running from near the bottom of each
cylinder to a common drain pipe, the end of which common drain pipe was
sometimes sealed and sometimes open. The theory of their operation was that the
water would be forced out through the discharge pipes by reason of the fact that
there was a greater pressure in the cylinder on top of the water in it than there
was in the common drain pipe. It was necessary to this operation that the pressure
on top of the water in the cylinder should be greater than the pressure in the
common drain pipe. But the pressure in the drain pipe was often equal to or
greater than the pressure in some one or more of the cylinders, in which case the
water would not be discharged from those cylinders: This would sometimes result

page_text: from the fact that all the water would be driven out from one of the cylinders, and
the steam from that cylinder would thus gain access to the common drain pipe and
thus equalize the pressure on the inlet and outlet ends of the separate discharge
pipes. Then the water would accumulate in these cylinders, and could not be
forced into the discharge pipe. Sometimes when the pressure in the common
supply pipe was four or five pounds, the pressure in the cylinders would be below
atinosphere, because the steam would be condensed in the cylinders more rapidly
than it would be supplied from the steam supply pipes thereto. In such cases the
water could not be forced through the discharge pipes of the cylinders.
In some cases, by reason of the condensation of the steam in some one or more of
the cylinders more rapidly than it was supplied thereto, the water from the common
drain pipe would flow into the cylinder and fill the same to a greater or less extent,
thereby greatly reducing its efficiency.
Another cause of trouble in controlling and regulating the temperature of the
cylinders was the presence and accumulation of air therein. The presence of air in
the cylinders would decrease by so much the space for the steam to occupy, and
therefore the working capacity of the cylinders.
In these machines it is of great importance that the cylinders should remain at
the same or a uniform temperature for a considerable period of time, that is to say,
that the heat of the cylinders should not vary materially from time to time. It is
of great importance to have perfect control over the temperature of the cylinders at
all times. It has been practically impossible heretofore to secure these results,
because it has been practically impossible to discharge the hot water as fast as it
. accumulated therein..
It will be apparent from what we have said, that in order to work such drying
cylinders in the most economical and most satisfactory way, it is necessary to
control in some certain and positive manner the discharge of the water of con-
densation, and to remove the air. The present invention is designed to accomplish
these results.
My improved apparatus is fully represented in the accompanying drawings which
show a paper drying machine.
In the accompanying drawings
Figure 1 is a front elevation view of a well known type of a paper drying
machine, showing five drying cylinders. More than five cylinders are usually
employed in such machines but the number shown in Figure 1 is sufficient for the
purpose of enabling me to describe the present invention.
Figure 2 is a vertical section through the axis of one of the cylinders. The
cylinders are all constructed in the same manner.
Figure 3 shows a form of valve to regulate the amount of water discharged from
the discharge pipe.
Referring to the drawings, A represents one of the drying cylinders of an
ordinary paper drying machine. This cylinder is mounted in suitable bearings
at a a in which, it revolves. B is the steam supply pipe for admitting the steam
from any suitable source into the interior of the cylinder. This pipe is connected
with the journal at one end of the cylinder, as represented in Figure 2. C is a
discharge pipe through which the water of condensation is discharged from the
cylinder. This pipe passes through one of the journals of the cylinder and its
inner end extends preferably down nearly to the bottom of the cylinder, or far
enough to enable the quantity of water in the cylinder to be kept at such a point
as may be desired, or substantially all removed. The outer or discharge end. 'of
this discharge pipe is provided at its lower end with a trap, preferably a valve
device, to prevent ingress at that point. In the form of apparatus shown in the
drawings at Figures 1 and 2 this trap is forined by an ordinary check valve D. K is a
common drain pipe for the water of condensation, with which the separate discharge
pipes from the separate cylinders are all connected. E is an escape pipe. It is
connected at one end with the discharge pipe C, above the point to which the water
of condensation must rise in the discharge end of the discharge pipe to pass through

page_text: the 'trap. I find in practice that a point below the highest part of the discharge
pipe, say six inches or more, is the best place at which to connect the escape pipe
with the discharge pipe. At the other end of the escape pipe I provide some
suitable means for keeping up the discharge through this pipe, such for example as
an ejector for producing a positive discharge by means of a jet of fluid, as
represented at F. The escape pipe is provided with a restricted passage or
opening G. This may be forined by some suitable valve, or it may be a restricted
passage in the pipe itself. The object of this restricted passage is to limit the
quantity of vapor or air passing through the escape pipe.
'H is an air pipe which extends into the cylinder through one of its journals. It
is preferably provided with an exhauster at its outer end, as represented at I. The
purpose of this pipe and exhauster is to remove the air from the cylinder. It is
also provided preferably with a restricted opening or with a valve of any suitable
form. An automatic valve to work by expansion by heat may be used upon the
air pipe, but I prefer to reduce the size of the pipe itself as at J, so as to form a
restricted passage.
In cases where the system is run under a pressure above the atmosphere, I prefer
to use upon the discharge pipe in place of an ordinary check valve, which is
represented at D as forming the trap, a check valve provided with a regulating
device which may be set to prevent the valve from discharging more than a given
quantity of water in a given period of time. In Figure 3 is shown a check valve
having such a regulating device.
The regulating device consists of a threaded spindle M, passing through the
threaded cup of the valve, and adapted to be screwed in or out so as to regulate.
the distance between the inner end of the spindle and the valve disc m.
The inner
end of the spindle thus acts as a stop to prevent the valve disc m from opening
beyond the point at which the stop is set. o is an ordinary lock nut to lock the
spindle in any desired position. By thus regulating the extent to which the valve
disc m can be opened, the amount of water discharged through the valve can be
controlled.
Each cylinder of the machine is constructed in the manner already described.
The discharge pipes from the cylinders connected with the common drain pipe K
from which the water is conducted to any point desired.
The operation of my improved apparatus is as follows. When the machine is
first started the cylinders are full of air. It is necessary to remove this air, and to
accomplish this result the air pipe H is opened and when an exhauster is used, it is
started. The air contained within the cylinder will pass.ont through this air pipe.
At the same time the valve in the steam supply pipe is opened and the supply
steam is admitted to the cylinder. The steam ut once begins to condense and the
water of condensation drops or flows down to the bottom of the cylinder and
collects at that point. As soon as a sufficient quantity of water has collected to
reach up above or seal the inner end of the discharge pipe, the exhauster connected
with the escape pipe is put into operation. It will be understood of course that
the exhauster of the escape pipe may be started at the same time as the exhauster
of the air pipe, or as soon as the steam is let into the cylinder, in which case it will
serve at the outset to assist in removing the air. When the water in the cylinder
has sealed the inner end of the discharge pipe, if the exhauster on the escape pipo
is in operation, the air or other contents of the escape pipe will be drawn out slowly
through the exhauster, producing a partial vacuum, or pressure lower than that
within the cylinder between the exhauster and the restricted passage or opening of
the escape pipe.
As soon as this partial vacuum or decreased pressure is produced
in the escape pipe the air and some of the other contents in the discharge pipe will
slowly pass out through the restricted opening of the escape pipe. By reason of
the fact that this opening or passage is restricted, the air or other contents of the
discharge pipe will be prevented from flowing out from the discharge pipe quickly.
As the discharge pipe becomes partially exhausted, the hot water from the
drying cylinder will rise in the discharge pipe C to its highest point and will then

page_text: flow down in a current towards the discharge end thereof; and as the opening or
passage of the escape pipe G is out of the dirent path of the water as it flows down
the discharge pipe, the greater part or the whole of such water flows downward
past the escape pipe and collects gradually in the discharge end of the discharge
pipe until it rises high enough to pass through the trap at the discharge end of this
pipe, after which the water begins to discharge therefrom separated from the air
and vapor which pass out through the escape pipe.
The escaping current of hot water and vapor from the cylinder is thus divided
between two discharge orifices, the one at the discharge end of the discharge pipe
for the greater part or the whole of the hot water substantially unmixed with air
or vapor, and the other formed by the escape pipe for the vapor with or without
air and with or without a small portion of the condensed water; and, as will be
noticed from the description above, these two discharge orifices are at different
levels. As the escape passage from the discharge pipe C is restricted, the escape
of the vapor is slow as compared with what it would be if there should be a free
escape passage of the full capacity of the discharge pipe. Moreover, as the
escope passage from the discharge pipe C is at one side thereof, it is out of the
direct path of the hot water downward to the trap at the lower or discharge end of
Baid discharge pipe.
When the trap at the discharge end of the discharge pipe is formed by a check
valve, the hot water collects until the column of water is sufficient to open the
check valve and discharge itself.
In this way the water of condensation is discharged automatically and certainly
whenever it collects in the cylinder in sufficient quantities to rise above the inlet
end of the discharge pipe. The cylinder is kept substantially free of water and
substantially its entire surface is utilized for the purpose of heating, the steam
admitted into the cylinder having access to substantially every part of the surface
of the inside of the cylinder.
The restricted passage or opening in the escape pipe may be varied in size,
according to the condition under which the machine is operated.
Thus in the different machines which have been operated by me in accordance
with this invention, I have varied the size of the restricted opening of the escape
pipe from about 3nd to about th of an inch in diameter.
By trapping the discharge end of the discharge pipe C of each drying or heating
cylinder separately, the entrance of stenu or water through the discharge pipe is
prevented; for even if the water should all be discharged from one cylinder and
the supply steam admitted to the common drain pipe K, the traps upon the
discharge pipes of the other cylinders would prevent the pressure in the drain pipe
from extending into their discharge pipes. This trapping of each discharge pipe
separately is one feature of my invention.
The operation of the check valve and controlling device shown in Fig. 3 is to
enable the discharge of water from the discharge pipe of any particular cylinder
to be regulated according to the amount of hot water collecting in that cylinder,
and thus to prevent the lower end of the discharge pipe from being entirely emptied
of water, as it might be if no controlling device were used and the system were run
under pressure. The different drying cylinders of a series employed to dry paper
have a different rate of condensation, for the work performed by each cylinder is
governed by the location of the cylinder, that is to say, the cylinders next to the
wet end or where the pulp comes to the driers, have to do considerably more work
than the cylinder next to the calender end. By graduating or controlling the
quantity of water that flows from each discharge pipe, the steam is prevented from
passing from that discharge pipe into the common drain pipe. When this regulating
device is not used and there should happen to be an excess of steam pressure in the
drying cylinder, the steam would be blown right through the discharge trap or
valve.
The escape pipes E from the different drying cylinders may all be connected
with a single exhauster, as shown in Fig. 1, and the air pipes H may also be

page_text: -
& Stugie exnatister. In some cases it may be expedient to have a
single exhauster with which all the escape pipes and all the air pipes are connected.
If the steam is supplied to each drying or heating cylinder at a pressure above the
at nosphere always sufficient to force the air and water out of the cylinder against
the atmospheric pressure, the exhausters are not necessary to the practice of my
improved method.
My invention when used with the drying oylinders of a paper machine results in
great economy in the operation of that machine. It makes it possible to run the
achine efficiently with a supply steam at atmospheric pressure or a pressure
below the atmosphere. Hence the drying cylinders can be supplied with exhaust
steam from an engine or other source, and the work accomplished by means of
steam which would otherwise be wasted. The water of condensation and the air
are removed from the cylinders us effectively and thoroughly when the steam is.
under a pressure less than that of the atmosphere as when it is above the same.
Substantially the entire interior surface of each cylinder is in active and constant
operation in the work of heating or drying. Under these conditions a supply of
exhaust steam under a pressure less than that of the atmosphere will in many cases
furnish all the heat that is required and will accomplish better and more uniform
results than have been accomplished without my improvement by a supply of steam
directly from the boiler under a considerable degree of pressure. In this way my
improvement secures a large saving in fuel.
My improvement also secures a uniformity and certainty of operation not possible
with former drying or heating cylinders. The accumulation of air and water in
the cylinder is prevented. The space within the cylinder to which the steam has
access is practically constant. This being so, and it being comparatively easy to
regulate the quantity of steam supplied to the cylinder, the cylinder can be kept at
a uniform degree of temperature, or its temperature can be regulated as may be
desired. When such machines are used without the application of my invention,
the water and air accumulate in the cylinder, and are present in different quantities
at different times, aud thus cause a constant variation in the temperature of the
cylinder not in any way under the control of the operator. This is a serious defect
in the operation of such a machine. My invention remedies this defect.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. The combination of a drying or heating oylinder with a discharge pipe
connected with one of the journals thereof, and a trap consisting of a valve
device at the lower end of the said discharge pipe, substantially as before set
forth.
2. The combination of two or more drying or heating cylinders, separate
discharge pipes, one connected with each cylinder, a trap consisting of a valve
device at the outer end of each discharge pipe, and a common drain pipe into which
the discharge pipes empty, substantially as before set forth.
3. The combination of two or more drying or heating cylinders, separate
discharge pipes, one connected with each cylinder, a trap consisting of a valve
device at the outer end of each discharge pipe, a regulating device to regulate
the amount of water that can be discharged from each discharge pipe, and a
common drain pipe into which the discharge pipes empty, substantially as before
set forth.
4. The combination of a drying or heating oylinder, a discharge pipe connected
with one of the journals thereof, a trap at the outer end of the said discharge
pipe and an escape pipe connected with the said discharge pipe above the outer end
thereof, substantially as before set forth.
5. The combination of a drying or heating cylinder, a discharge pipe connected
with one of the journals thereof, a trap at the outer end of the said discharge
pipe, an escape pipe connected with the said discharge pipe above the outer end
"
9

page_text: thereof, and an exhausting device with which said escape pipe is connected,
substantially as before set forth.
6. The combination substantially as before set forth, of a drying or heating
cylinder, a discharge pipe.connected with one of the journals thereof, a trap at the
outer end of the said discharge pipe, an escape pipe connected with.. the said
discharge pipe above the outer end thereof, the said escape pipe being provided
with a restricted passage.
7. The combination substantially as before set forth, of a drying or heating
cylinder, a discharge pipe connected with one of the journals thereof, a trap at
the outer end of the said discharge pipe, an escape pipe connected with the
said discharge pipe above the outer end thereof, the said escape pipe.being provided
with a restricted passage, and an exhausting device with which said escape pipe is
connected.
8. The combination of a drying or heating cylinder, a discharge pipe connected
with one of the journals thereof, a trap consisting of a valve device at the outer
end of the said discharge pipe, an escape pipe connected with the said discharge
pipe above the outer end thereof, and an exhausting device with which said escape
pipe is connected, substantially as before set forth.
9. The combination substantially as before set forth of a drying or heating
cylinder, a discharge pipe connected with one of the journals thereof,, a trap
consisting of a valve device at the outer oud of the said discharge pipe, an escape
pipe connected with the said discharge pipe above the outer end thereof, the said
escape pipe being provided with a restricted passage, and an exhausting device
with which said escape pipe is connected.
10. The combination substantially as before set forth, of a drying or heating
cylinder, a discharge pipe connected with one of the journals thereof, a trap at
the outer end of the said discharge pipe, an escape pipe connected with the said
discharge pipe above the outer end thereof, and a regulating device to regulate the
amount of water discharged from the said discharge pipe.
11. The combination substantially as before set forth of a drying or heating
cylinder, a discharge pipe connected with one of the journals thereof, a trap at
the outer end of the said discharge pipe, an escape pipe connected with the said
discharge pipe above the outer end thereof, an exhausting device with which said
escape pipe is connected, and a regulating device to regulate the amount of water
discharged from the said discharge pipe.
12. The combination substantially as before set forth of a drying or heating.
cylinder, a discharge pipe connected with one of the journals thereof, a trap at
the outer end of the said discharge pipe, an escape pipe connected with the said
discharge pipe above the outer end thereof, the said cacape pipe being provided
with a restricted passage, and a regulating device to regulate the amount of water
discharged from the said discharge pipe.
13. The combination substantially as before set forth of a drying or heating
cylinder, a discharge pipe connected with oue of the journals thereof, a trap at
the outer end of the said discharge pipe, an escape pipe connected with the said
discharge pipe above the outer end thereof, the said escape pipe being provided
with a restricted passage, an exhausting device with which said escape pipe is
connected, and a regulating device to regulate the amount of water discharged from
Baid discharge pipe.
14. The combination of a heating or drying cylinder with a steam supply pipe,
an air discharge pipe, and a water discharge pipe, the said three pipes being
connected with the journals of the said cylinder, substantially as before set forth.
15. The combination of a beating or drying cylinder with a steam supply pipe,
an air pipe, an exhausting device with which the said air pipe is connected, and
a water discharge pipe, the said three pipes being connected with the journals. of
the said cylinder, substantially as before set forth.
16. The combination substantially as before, set forth, of a heating or drying
cylinder with a steam supply pipe, an air pipe, an exhausting device with which

page_text: the said air pipe is connected, a water discharge pipe, the said three pipes being
connected with the journals of the said cylinder and a trap at the outer end of the
water discharge pipe.
17. The combination substantially as before set forth, of a heating or drying
cylinder with a steam supply pipe, an air pipe, an exhausting device with which
the said air pipe is connected, a water discharge pipe, the said three pipes being
connected with the journals of the said cylinder, a trap at the outer end of the
water discharge pipe, and an escape pipe connected with the water discharge pipe
above the outer end thereof.
18. The combination substantially as before set forth, of a heating or drying
cylinder with a steam supply pipe, an air pipe, an exhausting device with which
the said air pipe is connected, a water discharge pipe, the said three pipes being
connected with the journals of the said cylinder, a trap at the outer end of the
water discharge pipe, an escape pipe connected with the water discharge pipe above
the outer end thereof, and an exhausting device with which the said escape pipe is
connected.
19. The combination of a heating or drying cylinder with a steam supply pipe,
an air pipe, a water discharge pipe, a trap at the outer end of said water
discharge pipe, an escape pipe connected with the water discharge pipe above the
discharge end thereof, and provided with a restricted passage, substantially as
before set forth.
20. The combination substantially as before set forth of a heating or drying
cylinder with a steam supply pipe, an air pipe, a water discharge pipe, a trap at
the outer end of said water discharge pipe, an escape pipe connected with the
water discharge pipe above the discharge end thereof, and provided with a
restricted passage, and an exhausting device with which the said escape pipe is
connected.
21. The combination of two or more drying or heating cylinders, separate
discharge pipes, one connected with each cylinder, a trap at the outer end of each
discharge pipe, separate escape pipes connected with the said discharge pipes above
the outer end thereof and severally provided with restricted passages, and a common
exhausting device with which all the said escape pipes are connected, substantially
as before set forth.
22. The combination of two or more drying or heating cylinders, separate
steam supply pipes therefor connected with the journals of the said cylinders,
separate air pipes also connected with the journals of the said cylinders and
severally provided with restricted passages, and a common exhausting device
with which all of the said air pipes are connected, substantially as before set
forth.
WONDER uay u
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.