Journal mounted rotary joint

A rotary joint for a rotating heat exchanging drum directly attached to the end of the drum journal utilizes a flange and adapter to mount a seal on the journal and the joint body is fixed with respect to the journal and supports a seal plate in which an annular seal is biased toward the journal mounted plate by springs. The body mounted seal includes differential pressure area surfaces to balance the fluid pressures imposed thereon, and the springs are isolated from the fluid within the body. The joint eliminates metal-to-metal engagement of moving parts, and the seals may be readily replaced when worn.

BACKGROUND OF THE INVENTION 
Rotary joints are commonly employed with drying and cooling drums widely 
used in the paper manufacturing art, and related manufacturing processes, 
wherein an elongated web succesively engages steam-heated or water-cooled 
drums for treating the web. Such rotary joints include relatively 
stationary components communicating with fluid supply or exhaust and drain 
systems, and rotating components associated with the drum. The joints use 
a variety of seal arrangements to establish a sealed relationship between 
the rotating and stationary components, and various mounting arrangements 
are used with rotary joints to compensate for eccentricity in drum 
rotation, ease of installation and maintenance, economy of manufacture, 
thermal expansion, seal wear, etc. The most common mounting for rotary 
joints used with heat exchanging drums include nonrigid joint body 
supports which permit a limited movement or adjustment of the joint body 
relative to the drum journal and wherein limited eccentricity and thermal 
expansion conditions may be accomplished. 
In certain types of applications and installations of rotary heat 
exchanging drums it is known to directly mount a rotary joint seal in a 
fixed relationship to the drum journal or shaft. While this type of 
installation does create some problems, it has the advantage of permitting 
the rotary joint to be more compact in size as compared with a 
conventionally supported joint, misalignment problems are minimized, and 
fewer wearing parts are required. In such an installation, 
journal-supported components are affixed to the end of the drum journal 
and include a seal which is fixed with respect to the journal and 
concentric to its axis of rotation. The joint body is fixed with respect 
to the journal bearing support structure and includes a seal engaging with 
the journal supported seal to establish a relatively rotating, but 
fluid-tight, relationship between the journal and the joint body. A supply 
or drain conduit communicates with the body for supplying or receiving the 
fluid passing through the joint and drum. Springs are usually employed in 
the joint body to bias the body-mounted seal into engagement with the 
journal seal. 
Known journal-mounted rotary joints of the aforedescribed type are 
commercially available, but problems exist with such known joints, and it 
is an object of the invention to provide a journal-mounted rotary joint 
for rotating heat exchanging drums wherein the joint includes unique 
components and the parts of the joint are economical to manufacture and 
readily replaceable for service and maintenance purposes. 
Another object of the invention is to provide a journal-mounted rotary 
joint for heat exchanger drums wherein the joint includes a seal having 
differential area pressure faces wherein the forces imposed upon the seal 
by the internal fluid pressure are substantially balanced which produces 
less pressure at the seal contact surfaces to increase the seal life and 
lower the operating torque of the joint. 
Yet another object of the invention is to provide a journal-mounted rotary 
joint for heat exchanger drums wherein the journal-mounted seal and the 
joint body mounted seal are located within adapters and seal plates, 
respectively, which may be readily removed from their associated structure 
to facilitate repair and replacement. 
An additional object of the invention is to provide a journal-mounted 
rotary joint for heat exchanger drums wherein springs are employed to bias 
the joint body mounted seal toward the journal-mounted seal, and the 
springs are isolated from contact with the fluid medium within the joint 
reducing deleterious effects on the springs. 
In the practice of the invention, an annular flange is mounted upon the end 
of the journal (shaft) of a rotating heat exchanger drum by a set of bolts 
received within threaded holes defined in the end of the journal. An 
annular adapter plate is removably bolted to the flange and includes an 
annular seal coaxial with the journal axis and bore and having a radial 
sealing face. 
The rotary joint body is adjustably mounted in a fixed position upon the 
journal support structure adjacent the journal wherein the body will be 
stationary and may be accurately aligned with the journal axis. The body 
includes an internal chamber which communicates with a body port or 
conduit which may be attached to a supply for steam or hot or cold water, 
or the fitting may communicate with a drain system if the joint is 
employed with the discharge side of the drum. 
A radially oriented seal plate is bolted to the joint body and includes an 
internal cylindrical bore concentric to the journal axis which receives 
the cylindrical portion of a carbon seal supported in the seal plate. An 
O-ring is located between the carbon seal and the seal plate bore, and the 
carbon seal is capable of axial movement within the seal plate bore. 
Radial pressure surfaces are defined at each axial end of the carbon seal 
and the area of the surface which imposes an axial force on the seal 
toward the journal mounted seal is slightly greater than the differential 
pressure area imposing a force on the carbon seal in the opposite 
direction. Thus, the fluid pressure within the joint aids in maintaining 
the two seals in engagement, but the force with which the seals engage is 
controlled to extend the seal life and lower the operating torque. 
A plurality of compression springs are mounted in blind holes defined in 
the seal plate about its bore, and these compression springs engage a 
radial flange defined upon the carbon seal imposing a force on the carbon 
seal to insure engagement of the seal surfaces prior to the presence of a 
pressurized medium within the joint body. As the compression springs are 
isolated from the body chamber, and the fluid passing through the joint, 
the springs are not subjected to corrosion and adverse effects arising 
from fluid contact. 
The joint of the invention is so constructed that metal-to-metal contact of 
relatively moving parts does not occur, and the adapter and seal plate may 
be readily removed from their supporting components for replacement and 
service.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In FIG. 1 the outer end of the shaft or journal of a heat exchanging dryer 
drum, not shown, is shown at 10, and the journal includes a radial end 
face 12 perpendicular to the axis of rotation of the journal intersected 
by the journal bore 14 which communicates with the interior of the drum. 
The journal 10 is supported upon bearings, not shown, which are mounted in 
conventional journal-bearing holders mounted upon the journal support 
structure represented at 16. 
The heat exchanger drum with which rotary joints of the invention are used 
will usually be of the steam-heated dryer type, but the drum may receive 
cold water if the purpose of the drum is to cool the material engaging the 
drum periphery. Drums using rotary joints of the type herein disclosed 
will usually have a joint located upon each journal of the drum and one of 
the joints is usually employed to introduce steam into the drum, while the 
other joint removes the condensate therefrom. 
An annular flange 18 is bolted to the face of the journal 10 by a plurality 
of bolts 20 evenly spaced about the flange bore 20 which is coaxial with 
the journal bore 14. The flange includes a countersunk recess 24 for 
closely receiving the journal end, and the flange bore is recessed at 26 
for receiving the adapter as later described. 
An annular adapter 28 is bolted to the flange 18 by a plurality of bolts 30 
evenly spaced about the adapter bore 32. The adapter includes a concentric 
boss 34 closely received within the flange recess 26 and the adapter bore 
is concentrically countersunk at 36 to receive the annular stainless steel 
or silicon carbide seal 38. The seal 38 includes a reduced diameter 
portion received within the countersink 36, and an annular groove formed 
in the adapter receives the resilient O-ring 40 establishing a sealed 
relationship between the adapter and the seal. The seal 38 includes a 
flange larger than bore 32 having an outer radial flat sealing face 42 
perpendicularly disposed to the axis of the seal and the axis of drum 
rotation, and the flange of the seal 38 is provided with a blind hole 
receiving a key pin 44 also received within an aligned blind hole defined 
in adapter 28. Several key pins 44 may be used and these pins prevent 
relative rotation between the seal 38 and the adapter 28. 
A bracket 46 is bolted to the journal support 16 by bolts 48, and the 
bracket 46 is fixed relative to the journal 10 and rotating components of 
the drum. While only the lower portion of the bracket 46 is shown in the 
drawing, the bracket extends upwardly about and adjacent the joint 
structure. 
The joint body 50 is of a cast metal construction and is mounted upon the 
bracket 46. The downwardly extending body tang 52 includes a hole 54 which 
receives the threaded rod 56 mounted on the bracket, and nuts 58 threaded 
upon rod 56 located upon opposite sides of the tang 52 will accurately 
axially position the body in the direction of the drum rotative axis and 
bolts such as at 60 interposed between the body 50 and bracket 46 will fix 
the body to the bracket once the desired positioning thereto has been 
achieved. 
The body 50 includes a cylindrical chamber 62 coaxial with the journal bore 
14, and the bores of the flange 18 and adapter 28, and the chamber 
intersects the body side 64 to which a conduit fitting 66 may be attached, 
such as by bolts 68. The fitting 66 illustrated is an elbow to which a 
steam supply source may be attached, or if the joint is being used to 
remove water from the heat exchanger drum the elbow will be attached to a 
drain system, as known. The particular type of fitting mounted to the body 
50 is dependent upon the type of the supply or drainage conduits used, not 
shown. 
The body 50 is countersunk at 70 and provided with a radial face located 
adjacent the annular seal plate 72 bolted to the body by six bolts 74, 
circumferentially disposed about the seal plate bore 76. The seal plate 
includes an annular boss 78 closely received within the body countersunk 
recess 70 to insure concentricity with body 50, and the seal plate 
includes a concentric countersunk recess 80 surrounding the bore 76. As 
will be appreciated in FIG. 1, the seal plate 72 includes a radial vent 
passage 81 communicating with the recess 80 and the seal plate periphery, 
and an annular ring extension 82 defined on the seal plate axially 
overlaps the adapter 28. 
An annular seal 84 is mounted within the bore 76 and recess 82 of seal 
plate 72. The seal 84 is preferably formed of carbon and includes an axial 
bore 86, a reduced diameter cylindrical portion 88, and a radially 
extending flange 90. The seal includes a radial pressure face 92 located 
within the bore 76, and an annular axially extending lip 94 terminates in 
a radial face which sealingly engages the face 42 of the seal 38. As 
appreciated from FIG. 1, the configuration of the seal 84 includes a 
recess which defines radial shoulder 96 constituting a pressure face 
exposed to the fluid pressure within the seal bore, and the surface area 
of the face 96 is slightly less than the surface area of the end face 92. 
The seal portion 88 is grooved for receiving an elastomer O-ring 98 to seal 
the portion 88 to the seal plate 72 and the fit between the seal portion 
88 and the bore 76 is such that relative axial displacement between the 
seal and seal plate is possible. A plurality of blind holes 100, six in 
the disclosed embodiment, are bored into the seal plate parallel to the 
axis of the bore 76 and intersect the recess 80. A compression spring 102 
is located within each of the holes 100, and the springs extend from their 
holes for engagement with the seal flange 90 biasing the seal 84 toward 
seal 38. 
Two sets of opposed blind holes 104 and 106 are formed in the seal flange 
90 and seal plate 72, respectively, to receive the axially extending key 
pins 108 to prevent relative rotation between the seal plate and the seal 
84. The seal 84 is retained within the seal plate by snap ring 110 located 
within a groove defined in the seal plate and the snap ring will engage 
the flange 90 when the seal lip 94 has been worn to its maximum extent. 
During use, the components will be arranged as shown in FIG. 1, initially, 
the flange 18 will be bolted to the end of the drum journal 10, and the 
adapter 28 bolted to the flange with the seal 38 in place. The seal plate 
72 will be bolted to the joint body 50 and seal 84 will be retained within 
the seal plate by the snap ring 110. 
The body 50 is mounted upon the bracket 46, and adjusted thereto by means 
of the rod 56 and nuts 58 and fixed by bolts 60, and others, not shown. 
Initially, the body 50 will be so positioned that engagement of the seal 
face 42 with the end of the seal lip 94 will produce an axial separation 
between the snap ring 110 and the flange 90 approximately equal to the 
axial dimension of the lip. The springs 102 will be engaging the seal 
flange 90 and bias the seal lip into engagement with the seal 38. 
Introduction of a pressurized fluid medium into the body chamber 62, either 
from fitting 66, or as received from the drum through journal 10, will 
expose the seal faces 92 and 96 to this fluid pressure. As the force 
imposed upon the face 92 by fluid pressure tends to displace the seal 84 
toward the right, FIG. 1, and the force imposed upon the seal face 96 by 
the fluid pressure is toward the left, these two forces will oppose and 
tend to balance each other, and in view of the differential area, the 
force on the seal face 92 is slightly greater to the right which insures 
an effective engagement between the seal lip 94 and the seal 38. Of 
course, the springs 102 also aid in maintaining engagement between the 
seals 38 and 84, but due to the differential area of the faces 92 and 96 
unduly high sealing forces at the sealing faces is prevented which extends 
the effective life of the seals, and minimizes the resistance to rotation 
of the rotary joint reducing the torque requirements. 
As the lip 94 wears, the seal 84 will slowly move within the seal plate 
bore 76 toward the seal 38 to accommodate the wear and this automatic 
compensation will continue until the flange 90 engages the snap ring 110. 
At such time the joint would be dismantled and the seal 94 replaced. 
The vent passage 81 permits any leakage past the seals to be vented to the 
atmosphere, and a feeler gage may be inserted in the passage 81 to measure 
the wear that has occured at lip 94. 
It is to be noted that the springs 102 are isolated from the fluid pressure 
within the body 50 or seal plate 72 as the springs are located radially 
outside of the seal 84, and O-ring 98 and lip 94 will prevent exposure of 
the springs to the pressurized medium. Thus, the springs are not subjected 
to adverse corrosive conditions, and exposed to the direct heat of the 
fluid medium, as is the case with many rotary joint constructions. 
The rotary joint illustrated eliminates the possible misalignment of the 
joint with the drum journal in view of the rigid mounting of the body 50 
on the bracket 46. A joint constructed in accord with the disclosure is of 
a concise configuration, and a minimum of moving parts are required. 
Properly installed, there is no metal-to-metal contact between relatively 
movable parts, and as the seals 38 and 84 may be readily replaced, a joint 
of the described type has a very long effective life. The mounting of the 
seal 38 in the adapter 28, and the seal 84 in the seal plate 72 permits 
these relatively economically producible parts to be quickly replaced, 
when necessary, and maintenance of a rotary joint in accord with the 
invention requires only average mechanical skills. 
It is appreciated that various modifications to the inventive concepts may 
be apparent to those skilled in the art without departing from the spirit 
and scope of the invention.