Split face mechanical sealing rings and their use

Sectioned mechanical sealing rings divided into at least two sealing ring segments aligned by special aligning clips are described. Each ring segment has an arcuate inner wall portion having an arcuate recess therein traversing and extending laterally on both sides of the interface between adjacent segments. An aligning clip is positioned in the recess of one segment adjacent the interface and fastened so that it projects into the recess on the other side of the interface. The clips are U-shaped and the projecting U-shaped portions have essentially the same outer width as the width of the recess. When not inserted into the recess the legs of the clips diverge so that when installed in the recess, the legs lie flat and are tensioned against the walls defining the recess. By ensuring proper alignment of the segments, the clips minimize the possibility of damage to the sealing ring during installation, facilitate the overall assembly operation, and reduce the possibility of fluid leakage through the mechanical seal due to improper alignment. Moreover, the clips avoid the need for altering one or more of the co-engaging interfacial surfaces of the ring segments such as by boring, machining or otherwise creating holes or complex interlocking configurations in such surfaces.

TECHNICAL FIELD 
This invention relates to improved sectioned mechanical sealing rings for 
use in mechanical seals. 
BACKGROUND 
Mechanical seals are designed for use on a wide variety of machines having 
rotating shafts that pass through housings, such as pumps, agitators, 
blenders, separators, refiners, dryers and mixers. The function of the 
mechanical seal is to prevent leakage of pressurized fluids. In the 
mechanical seals to which this invention relates--sometimes referred to as 
a rotary face seal--sealing is achieved by arranging at least two durable 
sealing rings having extremely flat radially extending sealing faces 
axially adjacent to each other and concentrically disposed about the shaft 
so that the faces are in sealing contact. One ring is held stationary in 
the seal housing or gland while the other rotates with the shaft as part 
of a unit sometimes termed a rotary. 
Repair or replacement of parts of such seals is difficult whenever 
inaccessibility of the outboard end of the shaft or the location of the 
machine make it impossible to slip the seal off the end of the shaft. In 
such situations, the machines themselves must be disassembled. To 
facilitate such repair or replacement of parts, use has been made of 
radially split sealing rings and other seal parts so that each ring may be 
removed from, and new rings reassembled within, the seal and about the 
shaft. 
Typically, split rings are manufactured by cutting a whole ring into two 
segments. With cut rings, the cut faces of one ring segment thereby 
created are precisely lapped while discarding the other ring segment and 
mating the one segment with a segment from another whole ring of the same 
dimensions as a whole ring. Broken rings are also known and used. One type 
of broken ring, typically made of carbon, has irregular broken surfaces 
which permit self matching of the ring halves without lapping. On the 
other hand, broken rings formed by scoring and breaking rings made from 
silicon carbide or certain ceramic materials, tend to break quite cleanly 
and smoothly to provide substantially planar matching surfaces with only 
slight surface irregularities. 
Mechanical seals of various designs utilizing split sealing rings are 
disclosed, for example, in U.S. Pat. Nos. 2,996,319; 3,101,200; 4,576,384; 
and G. B. 917,693. In addition, mechanical seals employing such split ring 
technology are available as articles of commerce from a number of 
manufacturers. 
During installation of the split seal segments in the gland, precise 
alignment of the segments is essential. In the first place, proper 
alignment of the segments at the outset of installation minimizes the 
possibility of damage to the sealing ring through misalignment or 
incorrect contact between the co-engaging or abutting surfaces at the 
interfaces between the segments. This is especially important in the case 
of split sealing rings fabricated from carbon, silicon carbide or other 
similar ceramic or non-metallic materials, as segments made from such 
materials can become chipped or otherwise damaged if misaligned during 
assembly operations. Secondly, since the radially disposed sealing faces 
of the respective sealing rings must provide an extremely flat interface 
between these interacting faces, improper alignment, even if barely 
perceptible visually, can result in fluid leakage through the mechanical 
seal. This problem tends to be particularly troublesome in the case of 
silicon carbide or ceramic seals formed by scoring and breaking the ring 
to form substantially planar matching faces on the ring segments. And, in 
addition, if the ring segments can be placed in precise aligmnent easily 
and quickly, the overall assembly operation is greatly facilitated. While 
various alignment means for split rings have been designed or proposed 
heretofore, these have often required altering one or more of the 
co-engaging surfaces such as by boring, machining or otherwise creating 
holes or complex interlocking configurations in the seals at the 
co-engaging surfaces. 
SUMMARY OF THE INVENTION 
This invention avoids the problems noted above by providing highly 
effective and economical ways of suitably aligning the segments of split 
sealing rings without use of holes or complex interlocking configurations 
in or at the co-engaging surfaces of the sealing ring segments. 
In one of its embodiments this invention provides an improved sectioned 
mechanical sealing ring divided into at least two sealing ring segments. 
Each segment has (a) an arcuate outer wall portion; (b) a radially 
extended sealing face; (c) two sealing end surfaces, each sealing end 
surface being co-engageable with a sealing end surface of another such 
segment to form an interface between that pair of sealing end surfaces, 
and (d) an arcuate inner wall portion having an arcuate recess therein 
that extends laterally (and most preferably in a right angular direction 
away from) the interface so that when the segments are aligned with their 
sealing end surfaces in co-engagement, the arcuate recess traverses and 
extends laterally on both sides of each respective interface. The recess 
is defined in width by a pair of spaced-apart parallel radially extended 
interior wall faces of a pair of spaced-apart arcuate walls in each such 
segment. Rings of this configuration have been on sale and use in the 
United States for more than one year. However, the novel improvement in 
such sealing rings pursuant to this invention provides the solution to the 
above-noted problems. In accordance with this improvement, one of each 
pair of the co-engageable sealing end surfaces has projecting therefrom an 
aligning clip disposed between and engaging the interior wall faces of the 
recess on one side of the interface between the co-engageable sealing end 
surfaces of the sealing ring segments. Additionally, the clip is 
extendable into the recess on the other side of the interface to thereby 
maintain the sealing end surfaces in detachable co-engagement and 
alignment with each other. Thus when the sealing end surfaces are 
co-engaged and aligned with each other by means of the aligning clip, the 
sealing faces form a flat radially-disposed annular sealing end surface; 
the arcuate inner wall portions define an annular interior wall portion, 
and the arcuate outer wall portions define an annular exterior wall 
portion. 
The clip is a U-shaped clip mounted in the recess such that the legs are 
tensioned against the interior wall faces defining the recess on one side 
of the interface, and with the U-shaped portion projecting beyond the 
proximate sealing end of the segment. The projecting U-shaped portion has 
essentially the same outer width as the width of the recess. When not 
inserted into the recess, the legs of the clips diverge. When installed in 
the recess, the legs lie flat and are tensioned against the walls defining 
the recess. Thus when an adjacent mating segment of the sealing ring is 
installed, the U-shaped portion of the clip fits into the recess of the 
adjacent segment and aligns both segments. The fit between the projecting 
U-shaped portion of the clip and the interior wall faces of the recess of 
the adjacent segment is a slidable fit with no perceptible clearance and 
no perceptible interference between the clip and wall faces of the recess 
or groove into which the U-shaped portion extends. When properly aligned, 
the clip thus provides axial and radial alignment of the sealing ring 
segments. 
While the sealing ring can have more than two such segments, the preferred 
sealing rings of this invention are divided substantially diametrically 
into a pair of such sealing ring segments. Since one clip is employed at 
each interface between adjacent segments, two aligning clips are thus used 
with these preferred sealing rings composed of a pair a mating ring 
segments that define the complete ring. 
In another embodiment, the pair of spaced-apart arcuate walls that define 
the recess and the recess itself extend around substantially the entire 
interior of the assembled sealing ring. Thus in this embodiment all or 
almost all of the inner circumference of the assembled and properly 
aligned sealing ring is recessed or grooved. Most preferably, the arcuate 
wall remote from the radially extended sealing face of each segment has at 
least two spaced-apart transverse notches leading substantially at right 
angles from the recess. Each notch is thus disposed to receive a retainer 
to secure said segment to the gland of a mechanical seal against the 
tension of tension means disposed between the gland and the segment and to 
secure the segment against rotation in the gland. Use pursuant to this 
invention of the alignment clip in a sealing ring of this configuration 
results in the recess serving several functions. Firstly, the recess and 
walls deeming the recess serve as the retainer for the aligning clip. 
Secondly, the recess and walls defining the recess work in conjunction 
with the aligning clip to properly align the segments of the sealing ring 
during installation of the mechanical seal. And thirdly, the notches in 
the wall remote from the radial sealing face retain their ability to 
cooperate with the recess to provide an efficient way of receiving a 
retainer such as a retainer pin to secure the segment to the gland of the 
mechanical seal against the tension of tension means, such as coiled 
springs, disposed between the gland and the segment, and to secure the 
segment against rotation in the gland. 
In one embodiment, the aligning clip is adhesively bonded to the interior 
wall faces of the arcuate walls. In another form, the clip has a lateral 
extension that is shaped, sized and configured to fit over and onto one of 
the walls defining the recess with a portion of that extension bent so 
that it is tensioned against the outer face of that wall. Thus in this 
embodiment the clip need not be adhesively bonded onto the sealing ring 
segment. 
These and other embodiments and features of the invention will become still 
further apparent from the ensuing description, accompanying drawings and 
appended claims.

In the Figures, like numerals represent like parts among the different 
Figures. In some cases letters are associated with the same numeral to 
facilitate description by differentiating between more than one identical 
part. 
In order to ensure compliance with the best mode requirement of the patent 
law of the United States as it may be interpreted from time to time by the 
courts, the drawings as submitted with this application as filed include 
dimensional information pertaining to the then present best modes 
contemplated. It is to be understood and appreciated, however, that this 
invention is not intended to be restricted or in any way limited to such 
dimensional information except as may otherwise be expressly set forth in 
the claims hereof. 
FURTHER DETAILED DESCRIPTION 
In the form depicted in FIGS. 1 and 2 the aligning clip is a unitary body 
composed of U-shaped end 10 and a pair of spaced-apart leg portions 12,12, 
which are preferably of equal length. By virtue of the angular spread of 
the bend, the legs normally diverge from each other. However, as indicated 
for example in FIG. 11, when compressed and aligned in parallel by 
installation in a ring segment 14 between a pair of parallel wall faces 
16,16 with end 10 projecting beyond sealing end face 18, the legs are 
tensioned against and lie flat against the adjacent wall faces 16,16. For 
best results leg portions 12,12 are secured in place against the walls by 
means of a suitable adhesive such as an acrylic adhesive. As seen from 
FIG. 13, the projecting U-shaped end 10 fits into the recess defined by 
spaced apart wall faces 16A,16A of the mating ring segment 14A. As 
depicted in FIGS. 10-13, the pair of alignment clips used with a ring 
split into two segments are typically installed in the two ends of the 
same ring segment 14, but if desired, one clip can be installed in ring 
segment 14 to project and fit into an unoccupied mating recess of ring 
segment 14A, and the other clip can be installed in the recess at the 
other end of segment 14A to project and fit into the unoccupied mating 
recess at the other end of segment 14. A feature of the clips of this 
invention is that it is not necessary to hold a critical tolerance along 
the wall faces as the legs 12,12 readily adapt to minor surface 
imperfections that may possibly exist. However, the recesses themselves 
should be in suitable precise alignment on opposite sides of the interface 
so that when the clips are in place in the assembled sealing ring, the 
resultant annular radial sealing face is smooth and flat. 
FIGS. 3 and 4 depict the blanks from which the clips of FIGS. 1 and 2 are 
formed. Preferably the blanks are composed of thin strips of 304 stainless 
steel, but can be formed from other suitable materials which provide 
appropriate spring tension when bent into a symmetrical U-shape as 
depicted in FIG. 1 and compressed as depicted in FIG. 11. Among other 
suitable materials are blue tempered steel, carbon-steel and various 
stainless steel alloys. While the size of the strips is dependent upon the 
size of the ring segments, strips having a thickness falling in the range 
of about 0.008 to about 0.02 inch, more preferably about 0.01 inch, are 
typically employed. It is also preferred to provide chamfered edges and 
beveled or rounded corners to avoid the presence of any sharp edges. The 
materials from which segments 14 and 14A are fabricated can likewise vary. 
Preferably they are composed of silicon carbide, but may be formed from 
carbon or suitable ceramic, intermetallic or composited materials. 
The aligning clip in the form depicted in FIGS. 5-7 is a unitary body which 
is also composed of U-shaped end 10 and a pair of spaced-apart leg 
portions 12,12, which are preferably of equal length and normally 
diverging from each other as depicted in FIG. 5. And as indicated for 
example in FIG. 15, when compressed and aligned in parallel by 
installation in a ring segment 14 between a pair of parallel wall faces 
16,16 with end 10 projecting beyond sealing end face 18, the legs are 
tensioned against and lie flat against the adjacent wall faces 16,16. 
However, the aligning clip of FIGS. 5-7 is configured for installation on 
the ring segment without requiring use of any adhesive. This is 
accomplished by forming the clip from an L-shaped blank such as depicted 
in FIGS. 8 and 9 whereby portion 40 of the "L" of the blank is bent to 
form the U-shaped end portion 10 of the clip and creating a laterally 
extended clip on portion 20 which in the form depicted is shaped and sized 
to fit snugly onto rear wall 30 of segment 14. Thus in this case portion 
42 of the "L" of the blank is bent at right angles at two places to form 
lateral segment 22 which fits on top of wall 30 and pendant segment 24 
which fits snugly against rear face 32 of wall 30 to hold the clip in 
place. As seen from FIG. 17, the projecting U-shaped end 10 of this clip 
fits into the recess defined by spaced apart wall faces 16A,16A of the 
mating ring segment 14A. As depicted in FIGS. 14-17, one of the pair of 
these alignment clips is typically installed in one end of one ring 
segment 14 to project and fit into an unoccupied mating recess of ring 
segment 14A, and the other such clip is typically installed in the recess 
at the other end of segment 14A to project and fit into the unoccupied 
mating recess at the other end of segment 14. In this way both clips can 
have the same configuration--i.e., it is unnecessary to distinguish 
between a clip having a right-handed lateral extension and a clip having a 
left-handed lateral extension as would be required if the clips were 
configured for installation in the recess at both ends of only segment 14 
or of only segment 14A for insertion into the unoccupied end portions of 
the other segment. However, the provision and use of sets of clips, one 
having a right-handed lateral extension and the other a lefthanded lateral 
extension is within the purview and scope of this invention. 
The laterally extended clips of the clip-on configuration of FIGS. 5-7 have 
all of the advantages of the clips of FIGS. 1 and 2, and, as noted, do not 
require use of an adhesive to affix them on the rear wall of the seal 
segments. However, an adhesive can be used with the clip-on type clips if 
desired. It will be appreciated that the clip-on type of alignment clips 
are for attachment over and against the rear wall 30 of the sealing ring 
segments. The radial extended annular sealing face 50 of the sealing ring 
is to remain entirely flat and unencumbered by any extraneous object. 
As noted above, and as depicted in FIGS. 10-17, it is preferred to provide 
transverse notches 34 in the rear wall 30, i.e., the wall remote from wall 
38. Notches 34,34 are disposed to receive a retainer such as a pin to hold 
the aligned segments in place against a suitably disposed wall of gland 60 
against the tension of tension means such as a plurality of radially 
disposed springs 62. In this way the segment, and thus the assembled 
sealing ring is secured against rotation in the gland. 
Another feature of the improved sealing rings of this invention is their 
adaptability for use with any of a wide variety of mechanical seal 
assemblies. Thus this invention further provides a mechanical seal 
assembly comprising (i) a stationary gland having secured therein a 
non-rotatable split mechanical seal having an axially disposed sealing 
face, (ii) a rotary affixed to a rotatable shaft and including a 
mechanical seal disposed to rotate with the shaft and having an axially 
disposed sealing face adapted to sealably and rotatably engage the sealing 
face of the split mechanical seal, and (iii) means for maintaining the 
sealing faces in sealable engagement with each other, in which the split 
mechanical seal is a sectioned mechanical sealing ring in accordance with 
this invention. FIG. 18 illustrates one such assembly in which the sealing 
rings of this invention are preferably employed. 
Referring to FIG. 18 the assembly is a split mechanical seal composed in 
essence of gland 60 and its associated components, and rotary 80 and its 
associated components. The depicted components associated with gland 60 
include one of the radially disposed springs 62, centering spacer 64, ring 
segment 14 of a sectioned stationary ring secured against rotation in 
gland 60 by one of the retainer pins 70 and its holding clip 72, U shaped 
end 10 of an aligning clip of this invention, O-ring 74, O-ring 76, and 
gland gasket 78. The depicted components associated with rotary 80 include 
collar 82, rotary seal 84, collar gasket 86, set screw 88, O-ring 90, 
O-ring 92, and one of two cap screws 94 which secure the two collar halves 
82 together. As seen from FIG. 19, the two axially divided halves of the 
mechanical seal are secured together by means of cap screws 96 which are 
fitted with washers 98. As can be seen from FIG. 18, the space between 
housing 100 and the rotatable shaft of the apparatus with which the 
assembly is used is effectively sealed against pressurized fluid leakage 
from the interior of the housing. 
Typical non-limiting examples of some alignment clips of this invention are 
set forth below. 
EXAMPLE 1 
An alignment clip of the type depicted in FIGS. 1 and 2 is formed on a 
mandrel from strips of 304 stainless steel, each strip being about 0.88 
inch long, about 0.12 inch wide and about 0.01 inch thick. The clip has a 
U-shaped end with a radius of about 0.125 inch, and a pair of spaced-apart 
diverging linear leg portions of equal length which are about 0.42 inch 
apart at their free ends. These clips are especially adapted for use with 
a sectioned mechanical sealing ring in which the recess or channel is 
about 0.265 inch wide. Such seals are typically sized for use on rotatable 
shafts with diameters in the range of about 1.500 to about 2.625 inches. 
EXAMPLE 2 
An alignment clip of the type depicted in FIGS. 1 and 2 is formed on a 
mandrel from strips of 304 stainless steel, each strip being about 1.00 
inch long, about 0.16 inch wide and about 0.01 inch thick. The radius of 
the U-shaped end is about 0.140 inch. The pair of spaced-apart diverging 
linear leg portions of equal length are about 0.48 inch apart at their 
free ends. These clips are especially adapted for use with a sectioned 
mechanical sealing ring in which the recess or channel is about 0.296 inch 
wide. Such seals are typically sized for use on rotatable shafts with 
diameters in the range of about 2.750 to about 4.875 inches. 
EXAMPLE 3 
An alignment clip of the type depicted in FIGS. 1 and 2 is formed on a 
mandrel from strips of 304 stainless steel, of the same dimensions as 
those of Example 2. The U-shaped end of the clip has a radius of about 
0.156 inch. The pair of spaced-apart diverging linear leg portions of 
equal length are about 0.48 inch apart at their free ends. These clips are 
especially adapted for use with a sectioned mechanical sealing ring in 
which the recess or channel is about 0.312 inch wide. Such seals are 
typically sized for use on rotatable shafts with diameters in the range of 
about 5.000 to about 7.000 inches. 
It will be noted that an aligning clip of the type described in the above 
examples comprises a generally rectangular strip of flexible metal bent at 
its median portion into a generally U-shaped member in which the legs 
diverge, the member consisting of a central rounded portion and two 
diverging linear leg portions of essentially equal length. Generally 
speaking, the radius of the central U-shaped portion is in the range of 
about 0.1 to about 0.2 inches and the angle of divergence between the leg 
portions is in the range of about 30.degree. to about 40.degree.. 
The entire disclosure of each and every U.S. patent and of each and other 
publication of any kind, referred to in any portion of this specification 
is incorporated herein by reference. 
This invention is susceptible to considerable variation in its practice. 
Therefore the foregoing description is not intended to limit, and should 
not be construed as limiting, the invention to the particular forms of the 
invention described with reference to the Drawings or Examples. Rather, 
what is intended to be covered is as set forth in the ensuing claims and 
the equivalents thereof permitted as a matter of law.