Heat transfer roll and method

A means and method for attaining desired temperature conditions at not only the major extent of the heat transfer surface of a rotary heat transfer roll but also at the edges of the roll. Temperature conditioning fluid is introduced and distributed in part directly into a first end of an annular passage between an inner and an outer roll shell and in part into the annular passage adjacently downstream relative to the first end. Spent conditioning fluid is evacuated from the second end of the passage in part directly from the second end of the annular passage and in part through the inner shell adjacently upstream relative to the second end. While the roll is continuously rotating, the relative temperature conditioning effect of the conditioning fluid is adapted to be selectively controlled in respect to either or both ends of the temperature fluid circulating annular passage in the roll.

BACKGROUND OF THE INVENTION 
This invention relates to the art of effecting heat transfer between the 
perimeter of a rotary roll and a web travelling in contact with the 
perimeter, and is more particularly concerned with improvements attaining 
control of the heat transfer capability throughout the length of the heat 
transfer roll. 
Uniform transfer of heat from a rotating roll to a web is required in many 
applications, both within and outside of the paper industry. Sometime 
adjustable or differential heat transfer along the length of the roll may 
be required for special applications. Numerous attempts have heretofore 
been made to attain these ends, some employing very complex mechanical 
designs, and others more simple designs. Representative of the present 
state of the art are the following U.S. Pat. Nos.: 2,677,899; 2,697,284; 
2,919,904; 2,956,348; 3,838,734-all disclosing relatively simple heat 
transfer roll arrangements but without the fluid distribution control 
capability of the present invention. 
U.S. Pat. Nos.: 3,224,110; 3,309,786; 3,419,068; 3,581,812; 3,633,662; 
3,643,344; 4,120,349-all disclose more complex arrangements, but without 
the fluid distribution controlling capability of the present invention. 
More particularly, none of the listed patents provides for the control of 
roll edge temperature, that is the temperature at the opposite extremities 
of the outer or web contacting perimeter of the shell of the roll 
assembly, relative to or in combination with the heat transfer temperature 
of the greater intermediate portion of the heat transfer perimeter of the 
roll. 
SUMMARY OF THE INVENTION 
An important object of the present invention is overcome certain 
disadvantages, drawbacks, inefficiencies, shortcomings and problems 
inherent in prior heat transfer rolls. 
Another object of the invention is to provide a new and improved heat 
transfer roll and method for effecting heat transfer attaining efficient 
control of fluid distribution at the opposite extremities of the heat 
transfer surface of the roll as well as the intermediate area of the heat 
transfer surface. 
A further object of the invention is to provide a new and improved method 
of and means for controllirg the roll edge temperature of heat transfer 
rolls. 
Still another object of the invention is to provide a new and improved 
method of and means for effecting on-the-run control of edge temperature 
in a heat transfer roll 
The present invention provides in combination in a rotary heat transfer 
roll having concentric inner and outer differential diameter tubular 
shells defining an annular passage therebetween, roll heads closing 
opposite first and second ends of said passage, and means at said roll 
heads for mounting the roll rotatably for running on the perimeter of said 
outer shell of a travelling web to be temperature conditioned, means for 
introducing and distributing temperature conditioning fluid through said 
first end roll head, in part directly into said first end of said annular 
passage and in part through said inner shell into said annular passage 
adjacently downstream relative to said first end to join said directly 
introduced conditioning fluid and then to pass through said annular 
passage towards said second end, and means for evacuating spent 
conditioning fluid from said second end through said second end roll head, 
in part directly from said second end of said annular passage and in part 
through said inner shell adjacently upstream relative to said second end. 
Means are desirably provided, adapted to be operated while the roll is 
continuously rotating, for selectively controlling the relative 
temperature conditioning effect of both parts of the conditioning fluid in 
respect to either said first end or said second end or both ends of said 
passage. 
The invention also provides a new and improved method of controlling heat 
transfer in a rotary heat transfer roll having concentric inner and outer 
differential diameter tubular shells defining an annular passage 
therebetween, roll heads closing opposite first and second ends of said 
passage, and means at said roll heads for mounting the roll rotatably for 
running on the perimeter of said outer shell of a travelling web to be 
temperature conditioned, comprising introducing and distributing 
temperature conditioning fluid through said first end roll head, in part 
directly into said first end of said annular passage and in part through 
said inner shell into said annular passage adjacently downstream relative 
to said first end and thereby joining with said directly introduced 
conditioning fluid, circulating the joined conditioning fluid through said 
annular passage toward said second end, and evacuating spent conditioning 
fluid from said second end through said second end roll head, in part 
directly from said second end of said annular passage and in part through 
said inner shell adjacently upstream relative to said second end. While 
the roll rotates continuously, selective controlling of the relative 
temperature conditioning effect of both parts of the conditioning fluid 
may be effected with respect to either said first end or said second end 
or both ends of said passage.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
A rotary heat transfer roll 5 (FIG. 1) embodying the present invention has 
concentric inner and outer differential diameter tubular shells 7 and 8, 
respectively, defining an annular passage 9 therebetween. A first roll 
head 10 closes a first end of the shells 7 and 8 and the passage 9, and a 
second roll head 11 closes the opposite second end of the shells 7 and 8 
and the passage 9. Each of the roll heads 10 and 11 has means such as a 
journal 12 for mounting the roll 5 rotatably for running on the perimeter 
of the outer shell 8 of a travelling web 13 to be temperature conditioned. 
Although the roll shells 7 and 8 may be attached in endwise abutting 
relation to the inner faces of the roll heads 10 and 11 as shown in FIG. 
1, a preferred assembly comprises mounting of the first end of the inner 
shell 7 within a rabbet groove 14 provided therefor on an inwardly 
projecting hub 15 on the roll head 10. Attachment of the first end of the 
outer shell 8 to the roll head 10 is adapted to be effected by engaging 
such end in a complementary rabbet groove 17 in the inner face of a 
radially outer annular portion of the head 10. Similarly, the second end 
of the inner shell 7 is adapted to be engaged in a complementary rabbet 
groove 18 in an inwardly projecting hub 19 on the head 11. At its second 
end, the outer shell 8 is fixed to the head 11 in a complementary rabbet 
groove 20 in the inner face of a radially outer portion of the head 11. 
Means are provided for supplying temperature conditioning fluid through the 
first head 10 to circulate through the annular passage 9 and then to be 
evacuated through the second roll head 11. More particularly, the supplied 
and circulated temperature conditioning fluid is controlled to attain a 
desired heat transfer relationship of the roll edges, that is at the ends 
of the outer shell 8 with respect to the intermediate, major length of the 
outer shell. To this end, the temperature conditioning fluid may be 
supplied at a given desirable temperature from a suitable source through a 
supply line 21 to a pair of line branches 22 and 23 which connect through 
a siphon type rotary joint 24 with passageway means leading through the 
journal 12 of the head 10 to the inner end of the head. In a preferred 
arrangement, the branch 22 communicates through the joint 24 with a 
passageway 25 formed concentrically longitudinally through the journal 12 
and of a diameter to accommodate in clearance relation a smaller diameter 
concentric tube 27 providing a passageway 28 with which the branch 23 is 
connected. Control over the volume of conditioning fluid delivered into 
the first end of the roll 5 is by means of valves 29 and 30 in 
respectively the lines 22 and 23. 
Conditioning fluid from the passageway 25 is distributed through a 
plurality of equidistantly spaced radial passageway branches 31 (FIGS. 1, 
2 and 3) to the first end of the passage 9 in a manner to condition the 
temperature of the first end portion of the outer shell 8. By preference, 
the branches 31 discharge into an annular stilling chamber 32 defined in a 
space about the hub 15, the inwardly facing wall of the head 10 and the 
adjacent first end of the inner shell 7, at the first or upstream end of 
the passage 9. 
Conditioning fluid delivered to the passageway 28 discharges into a fluid 
reception chamber 33 defined between the inner end of the head hub 15 and 
a partition 34 spaced in a limited distance inwardly from the hub and 
secured as by means of welding 35 in sealing relation across the interior 
of the shell 7. At its inner end, the tube 27 is secured in place as by 
means of a flange 37 fixedly secured to the tube and attached to the inner 
end of the hub 15, as by means of screws 38. 
For effecting communication between the chamber 33 and the annular heat 
transfer passage 9, ports 39 extend through the wall of the inner shell 7. 
For maximum efficiency, annularly arranged equidistantly spaced sets of 
the ports 39 are provided. Discharge from the ports 39 is prevented from 
impinging directly from the ports onto the outer shell 8, and for this 
purpose an annular baffle 40 is mounted on the adjacent end portion of the 
inner shell 7 and extends inwardly over an annular distribution groove 41 
into which the ports 39 discharge. The baffle 40 directs the fluid from 
the ports 39 downstream and at relatively low velocity from an annular 
orifice defined between the end of the baffle and an annular lead-out 
surface 42 sloping in a downstream direction at the inner end of the 
groove 41. Thereby the fluid passes smoothly from the flaringly chamfered 
free end of the baffle into the passage 9 where the fluid joins, mixes 
with, and circulates downstream with the fluid which was directly 
introduced into the first end of the passage 9 in heat transfer relation 
to the first end of the outer shell 8 at the stilling chamber 32 and flows 
with substantially uniform velocity to join the treating fluid issuing 
from the annular orifice defined at the exit end of the baffle 40. Thence, 
the joined and mixed increments of the conditioning fluid circulate 
downstream through the passage 9 in heat transfer relation to the major 
intermediate extent of the outer shell 8 and toward the second end of the 
passage 9 at the roll head 11. 
Evacuation of spent conditioning fluid is effected through the roll head 
11, in part directly from the second end of the passage 9 and in part 
through and from a second reception chamber 43 similar to the first 
reception chamber 33 but with fluid flow in reverse direction. That is, 
the chamber 43 is defined between a partition 44 sealingly secured as by 
means of welding 45 across the interior of the inner shell 7 in suitably 
adjacently spaced relation to the inner end of the roll head 11 and more 
particularly the hub 19. Communication between the second or downstream 
end portion of the passage 9 and the chamber 43 is effected through second 
ports 47 (as distinguished from the first ports 39) and desirably in a 
similar arrangement as the ports 39 comprising two annular rows of the 
ports 47 extending radially through the wall of the inner shell 7. From 
the chamber 43 the spent fluid is drawn off through a passageway 48 in a 
tube 49 extending through the head 11, and which has its entry end in 
communication with the chamber 43 and is supported by an attachment flange 
50 secured to the inner end of the hub 19 as by means of screws 51. 
To provide a passageway 52 for communication through the roll head 11 with 
the downstream end of the chamber 9, a bore 53 of larger diameter than the 
tube 49 extends axially through the head 11 and is closed at its inner end 
by the flange 50. Communication between the passageway 52 and the second, 
downstream end of the passage 9 is effected by means of a plurality of 
circumferentially spaced radial branch passageways 54 through the hub 19. 
From the outer end of the journal 12 of the roll end 11, the passageways 48 
and 52 communicate with a siphon-type rotary joint 55. From the joint 55 
the passageway 48 communicated by way of a branch line 57 with an 
evacuation line 58, and the passageway 52 communicated by way of a branch 
line 59 with the evacuation line 58. Each of the branch lines 57 and 59 
desirably has a respective control valve 60. 
From the foregoing it will be apparent that means are provided for 
attaining substantially improved heat transfer control, especially at the 
roll edges, that is at the opposite ends of the outer, heat transfer roll 
shell 8. For this purpose, the upstream or supply control valves 29 and 30 
and the downstream or evacuation control valves 60 provide means for 
adjusting the divided conditioning flow increments at the first or 
upstream end of the roll and at the second or downstream end of the roll 
throughout a very wide range. While often as nearly as practicable 
uniformity of heat transfer throughout the length of the heat transfer 
passage 9 may be desired, operating conditions, and more particularly 
variations in requirements for the travelling web 13 may require 
adjustments in the heat transfer ratios between either or both of the roll 
edges and the intermediate span of the heat transfer surface provided by 
the outer shell 8. For example, if it is necessary to increase the heat 
transfer function at the first or upstream edge of the heat transfer 
surface relative to the remainder of the heat transfer surface, the valves 
29 and 30 may be adjusted to increase the volume of heat transfer fluid to 
the stilling chamber 32 as compared to the volume delivered to and 
distributed from the first chamber 33. If the reverse condition is 
desirable, the control valves are adapted to be adjusted to increase the 
volume of temperature conditioning fluid to the chamber 33 relative to the 
volume of conditioning fluid supplied to the stilling chamber 32. 
Similarly, at the downstream or second end of the heat transfer roll, 
effective control is attained by means of the control valves 60. If 
increased heat transfer is desired at the second or downstream roll edge, 
the volume of heat transfer fluid evacuated through the passageway 52 is 
increased relative to the volume increment of the fluid evacuated through 
the chamber 43. For a reverse condition, the incremental volumes of the 
heat transfer fluid evacuated through the respective passages 52 and 48 
may be reversed. It will be understood that the heat transfer fluid may 
either be a heated fluid for transferring heat through the outer shell 8, 
or it may be a heat reducing or chilling fluid for effecting a reverse 
heat transfer function, that is to chill the heat transfer surface of the 
outer shell 8. In either case efficient heat transfer control is 
attainable not only along the major extent of the heat transfer surface 
but also at each end of the heat transfer surface, that is at each edge of 
the heat transfer roll, by adjusting the flow rate ratio between the roll 
edge areas and the intermediate areas of the heat transfer surface. 
If operating conditions require a wider range of temperature control of the 
outer shell heat transfer surface than may be attainable by supplying the 
heat transfer fluid from a common source for each of the divided 
increments, separate differential temperature fluid sources may be 
employed as indicated in FIG. 4. Thus, a fluid source 61 may be provided 
communicating by way of a line 62 through a control device such as a valve 
or orifice 63 and by way of the rotary joint 24 with the passageway 
delivering to the upstream end of the heat transfer passage 9 by way of 
the stilling chamber 32. A separate heat transfer source 64 supply by way 
of a line 65 and a control device 67 through the joint 24 to the 
passageway 28 delivers to the receiving chamber 33 For heating heat 
transfer the temperatures of the heat transfer fluid from the respective 
sources 61 and 64 may vary to any extent desired. To the same effect where 
chilling function is desired, the chill factor of the fluid supplied from 
the respective sources 61 and 64 may be in whatever differential required 
At the second or downstream end of the heat transfer roll 5, a similar 
arrangement as in FIG. 1 may be employed unless the flow rate ratios 
required cannot be handled through a common evacuation line, or it is 
desired to return the evacuated fluid separately to the respective sources 
for recycling. 
While any of the control devices 29, 30 and 60 in FIG. 1, and 63 and 67 in 
FIG. 4 may be manually adjusted, it will be apparent that means for 
automatic adjustment may readily be provided under the control of 
temperature sensors, or the like. Advantageously, the adjustments can be 
effected on the run and without stopping the heat transfer roll 5. 
It will be understood that variations and modifications may be effected 
without departing from the spirit and scope of the novel concepts of this 
invention.