Split mechanical face seal

Abstract: A split mechanical face seal is disclosed comprising a pair of seal rings each comprising split ring segments secured about the circumference by securing means; the rings are non-ridgedly supported in an axial direction by resilient support means; at least one of the support means comprises biasing means axially biasing the sealing sur­ face of the rings together.

Description: The invention relates to mechanical seals for pumps and the like, particularly to split mechanical face seals. Mechanical seals are used on a wide variety of machines, e. g., pumps, having rotating shafts that pass through housings, for preventing leakage of pressurized fluids. In one type of mechanical seal, the rotary face seal, sealing is achieved by arranging at least two rigid, durable sealing rings having extremely flat radially extending sealing faces axially adjacent each other and concentrically 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. For example, there are known from US -A- 2 299 395 (A.E. KARLBERG) or EP -A- 0 120 158 (BORG-WARNER CORP.) mechanical face seals, preferably for use with compressors and slurry pumps, respectively, provided with sealing rings which are supported by resilient support means contacting and supporting each sealing ring in the seal and one of the support means also comprising biasing means axially biasing the sealing rings and sealing surfaces thereof together. However, repair or replacement of parts of such seals is difficult whenever inaccessibility of the outboard end of the shaft or the location of the respective machine makes it impossible to slip the seal off the end of the shaft. In such situations, the machines themselves must be disassembled. A known solution, e.g. US -A- 3 101 200 (H.E. TRACY), has been to split the sealing rings and other seal parts into two or more parts so that each ring may be removed from, and new rings may be reassembled within, the seal and about the shaft without disassembly of the entire machine. Such split rings are manufactured, typically, by cutting a whole ring into two segments. In operation of a mechanical face seal device, whether the sealing rings are split or not, the sealing surface of each ring must be exceptionally flat in order to adequately seal against the cooperating sealing surface of the other ring. Typically, the sealing surface of each ring is lapped to an extreme flatness of 0.12 µm (two helium light bands). These precisely lapped sealing ring surfaces must mate accurately, and again without distortion. With cut rings, cf. again US -A- 3 101 200 (H.E. TRACY), 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, similarly machined, so as to form a segmented ring of the same dimensions as a whole ring. Broken rings are also known in the art in which the irregular broken surfaces permit self matching of the ring halves without lapping. In any event, precise alignment of the seal ring faces in such seals is achieved by machining for very small tolerances, such as lapping, the backs as well as the faces of the rings, and then mounting the split rings in rigid holders. The holders, themselves, must be carefully lapped to receive the lapped backs of the split rings. Then, the ring/holder assemblies are precisely aligned and rigidly held with respect to each other by clamps, pins, screws, dowels or the like. Specifically, this rigid clamping rigidizes the split rings into unsplit-like rings. This requires lapping of the back face of the rings and of the mating face of the holder which clamps the rings into the seal so as to close any leakage path between these hard mating surfaces and also so as to avoid mechanical distortion of the clamped ring as may arise from a non-uniformity in the hard clamping of the ring; such mechanical distortion can cause leakage at the distorted sealing surface of the ring where it fails to perfectly mate with the sealing surface of the opposed seal ring. Further prior art seals which have split seal rings attempt to overcome the need, as of US -A- 3 101 200 (H.E. TRACY), for lapping both the back face of the seal ring and the adjoining face of the clamping structure by interposing a resilient member. BEZAK , Design And Application Of Split Mechanical End Face Seals, in Journal of the American Society of Lubrication Engineers, June 1978, p. 305 , shows a split mating ring stator mounted to a gland with a split mating ring gasket interposed. The split rotor primary ring is mounted to the shaft by a rotor holder assembly including a snap ring against a split back-up ring, supported by a disc, retainer, drive band and spring on a drive sleeve. A second split back-up ring is mounted between the primary ring and the shaft, adjacent to secondary split O-rings. The rotor ring and the stator ring each have a flat radially extending sealing surface. The spring biases the holder assembly to urge the sealing surfaces together. The BEZAK reference is unclear as to the type of mounting for the split ring stator, although it appears that it is a non-rigidly mounted split stator ring. In any event, the split rotor ring is rigidly secured in a complex rotor holder assembly. BURGMANN , Mechanical Seals Design Manual 10, Edition E 5000-05/77, ca. 1977, p. 82, shows two seals, M43S and HS-D , each having a holder which is used to clamp together the halves of a split ring so held. This clamping obtains an unsplit-like ring. After a split rotor ring is thus rigidly secured and clamped, the sealing surface thereof is mated with the sealing surface of a split stator ring, also so clamped, to obtain sealing. The outer circumference of the rotor and stator split rings includes a circumferential radial projection. An O-ring (one on each side of the radial projection) is trapped between the inner wall of the clamping device which holds the ring halves together and the clamped ring and its radial projection. This clamping rigidizes the split ring halves of each ring into an unsplit-like ring, while the clamped O-ring reduces the need for lapping the clamped surfaces. Specifically, the clamping device presses down upon the O-rings, driving the trapped O-Rings into the seal ring on both sides of the radial projection. Thus, the radial projection is clamped in between the two clamped O-rings, which prevents radial and axial movement of the halves of the ring. Therefore, this clamping design rigidizes the clamped ring into an unsplit-like ring while reducing the need for lapping the back surface of the clamped ring and the adjacent surface of the clamp by virtue of the interposed O-rings. In the M43S seal, furthermore, the back face of the rotor is contacted by the mating face of the thrust ring under load from the adjacent hydraulically loaded O-ring, which axially constrains the rotor. In the HS-D seal, the split rotor is rigidly constrained axially between the hard faces of two clamped split stators. It is further noted that the rotary holder of both seals is split radially, so that a capping section may be moved axially along the shaft away from central section to permit insertion of replacement split seal ring halves without disassembling the entire equipment. Over time, the surfaces of the holder can become pitted and worn in use, however, they cannot be replaced without disassembling the entire equipment. This is an expensive and time-consuming inconvenience. The technical problem of the invention regarding the prior art is to provide a split mechanical face seal which eliminates the need for expensive and time-consuming precision alignment and machining for very small tolerances , such as lapping , of split seal ring surfaces other than the sealing surfaces themselves , specifically to provide sealing functions in a split seal which are enhanced by fluid pressure. The solution to this problem is accomplished by a split mechanical face seal according to the characterizing part of claim 1 . Specifically, the invention features a pair of seal ring assemblies in a split mechanical face seal. Each ring assembly comprises a rigid seal ring of split ring segments and securing means extending about the circumference thereof holding the segments together. The rings each have a flat, radially extending sealing surface, the sealing surface of the rings in sealing contact with each other. Resilient support means non-rigidly support each ring axially on a side thereof opposite the sealing surface thereof, one such support means also biasing the rings and sealing surfaces thereof together. The benefit of this solution according to the invention is to permit small axial and radial floating movements of the split ring halves so that they can self-align into leak-free cooperation at their mating seal faces. In preferred embodiments, the seal further comprises a seal gland having gland halves fastened together defining a chamber therewithin. One of the seal ring assemblies comprises one seal ring and is supported by the gland in the chamber. The other seal ring assembly comprises a holder comprised of holder halves fastened together supporting the other of the seal rings, the holder adapted for connection to a shaft and for rotation therewith. The rings are exposed about a portion of their outer circumference to the chamber and fluid pressure therein which assists in holding the ring segments together. The rings comprise ring halves and have adjacent irregular mating split faces in mating contact with each other. An elastomeric member extending about the one seal comprises the securing and resilient support means for the one seal, supporting the one seal in spaced relation to the rigid walls of the seal gland, the member contacting opposed radially extending surfaces of the one wall and the gland. Similarly an elastomeric member extending about the other seal comprises the securing and resilient support means for the other seal, supporting the other seal in spaced relation to the rigid walls of the holder, the member contacting opposed radially extending surfaces of the one wall and the holder. The resilient support means for one of the seals also comprises compression springs, the springs biasing the sealing surfaces of the rings together. The holder halves are spaced apart to form gaps at their split faces. A groove on the interior surface of the holder has an elastomeric member therein for sealing the shaft. A groove in one of each pair of split holder faces has a gasket therein sealing the gap therebetween, the groove and gasket exposed to and the gasket contacting the elastomeric members in the interior groove of the holder and supporting the other seal ring therein. The gasket has a lower durometer than that of the elastomeric members which it contacts. An elastomeric gasket is also provided in a groove provided in one of each pair of split faces of the gland. The gland gasket extends between end walls of the gland and, at one end, is reversed in a U-shaped configuration to contact the elastomeric member supporting the one seal ring in the gland, the gasket having a lower durometer than that of the supporting elastomeric member. At the other end, the gasket extends radially inwardly and is exposed to and contacts a face gasket in an annular recess in an end wall. We first briefly describe the drawings. Drawings Fig. 1 is a plan view of a split seal, partially broken away; Fig. 2 is an isometric view of one seal gland half and the inner seal assemblies; Fig. 3 is an exploded isometric view of a split seal half and internal elastomeric seals; Fig. 4 is a side view, partially broken away, of the seal, taken along the line 4-4 of Fig. 1, mounted on a shaft and bolted to a mounting surface; Fig. 5 is a fragmentary view partially in section of the seal half illustrated in Fig. 1, taken along the line 5-5 of Fig. 1; Fig. 6 is an enlarged fragmentary view of the mating free ends of an elastomeric ring; Fig. 7 is a sectional view of an expandable arbor and a sealing ring; Fig. 8 is a sectional view taken along line 8-8 of Fig. 7; and Fig. 9 is a view similar to that of Fig. 5 of an alternate embodiment. Structure Referring to the drawings, particularly Fig. 1, mechanical seal 10 comprises a seal gland having two identical stainless steel gland halves 11, 12 each of which has two fastener recesses 13 to accomodate bolts 15, shown in Fig. 4, to mount seal 10 about shaft 17 to a mounting surface 60 of a pump or the like. Gland plate halves 11, 12 together define seal chamber 19 housing stationary split seal ring assembly 14, and rotary split seal ring assembly 16, as shown in Fig. 2. Seal 10 defines a central axially extending opening for receiving shaft 17 therethrough. Gland halves 11, 12 are identical. As illustrated in Figs. 1, 2 and 3, gland halves 11, 12 have, respectively, smooth split gland faces 20, 21 and grooved split gland faces 22, 23. Smooth faces 20, 21 have two axially spaced untapped holes 24 and grooved faces 22, 23 have two axially spaced partially tapped and partially untapped holes 26. Gland halves 11, 12 are assembled, as shown in Fig. 1, with the smooth faces 20, 21 opposing, respectively, the grooved faces 22, 23; and shoulder socket head cap screws 28 are inserted through untapped holes 24 and screwed into tapped holes 26 to secure the gland halves 11, 12 together, the shoulder portions of screws 28 engaging the untapped walls of holes 24, 26 to align the gland halves 11, 12. Best shown in Figs. 3 and 4, one end wall 30 of gland halves 11, 12 has a central opening defined by axial wall 31 slightly larger than the diameter of shaft 17 to provide clearance as the shaft projects therethrough. The other end wall 32, comprising a mounting wall, has a coaxial opening defined by wall 33 larger than the opening in the mounting surface 60 of the pump or the like to which it is to be attached, as shown in Figs. 4 and 5. Internal axially extending wall 34 has an enlarged diameter relative to the openings defined by walls 31 and 33 and defines the major internal diameter of seal chamber 19. Wall 33 tapers outwardly from the opening which it defines to wall 34. Best shown in Fig. 3 radial wall 35 extends outwardly from wall 31 to a step formed by axial wall 36 and radial wall 37, the latter joining wall 34. Mounting wall 32 is provided with a recess 38 about the opening defined by wall 33 to receive a split elastomeric face gasket 58 adhesively secured thereto, face gasket 58 having an axial dimension greater than the depth of recess 38, as shown in Figs. 2 and 3. The inner diameter of face gasket 58 is equal to that of the opening defined by wall 33. The grooved split gland faces 22, 23 of the gland halves are each provided with a groove 40 of generally square cross section. The major segment 42 of groove 40 extends axially between end walls 30, 32, spaced radially between seal chamber 19 and holes 26. Adjacent end wall 32 a segment 44 of the groove extends at right angles from segment 42 to wall 33, segment 44 being located below and exposed to recess 38. Adjacent end wall 30, groove 40 is reversed in a generally U-shaped configuration, a segment 45 of the groove extending at a right angle from segment 42, in line with radial wall 35, to axial wall 36; another groove segment 46 extending at a right angle from segment 45 to radial wall 37, segment 46 exposed to axial wall 36. An elastomeric gland gasket 50, preformed to the configuration of groove 42, is placed in the groove, best shown in Figs. 2 and 5. Gland gasket 50 comprises segments 52, 54, 55, 56 corresponding respectively to groove segments 42, 44, 45, 46. Gland gasket 50 in groove 42 projects thereabove for sealing contact with a mating ungrooved split face 20, 21 of another gland half. Segment 56 of gasket 50 projects above groove segment 46 beyond wall 36 and projects a short distance beyond the end of groove segment 46. At the other end, segment 54 of the gland gasket projects to or slightly above groove segment 44 for sealing contact with face gasket 58; the end of segment 54 is cut at a tapered angle, the direction of the taper being the same as the taper of wall 33. The split ends of face gasket 58 are arranged to meet at a position offset slightly, e.g. 3.2 mm (1/8 inch), from the split between the gland halves and segment 54. As illustrated in Figs. 2 and 3, rotary split seal ring assembly 16 is provided within the gland, formed by gland halves 11, 12, adjacent tapered wall 33. Assembly 16 comprises a holder having two identical holder halves 70, 71, each having, respectively, smooth split holder faces 72, 73, and grooved split holder faces 74, 75. Smooth faces 72, 73 have two untapped fastener holes 76; and grooved faces 74, 75 have two tapped fastener holes 77. Holder halves 70, 71 are assembled with the smooth faces 72, 73 opposing, respectively, the grooved faces 74, 75. Faces 72, 74 and 73, 75 when holder assembly 18 is assembled on a shaft 17, define, respectively, gaps 68 and 69 between the holder halves 70, 71. Socket head cap screws 78 are inserted through untapped fastener holes 76 and screwed into tapped fastener holes 77 to secure the holder halves 70, 71, together. Radial end wall 90 of holder halves 70, 71 has an outer diameter slightly smaller than the opening defined by gland walls 32, 33 thereadjacent. The inner diameter of holder halves 70, 71 adjacent wall 90 defined by inner axial walls 85, 86 is equal to the diameter of the shaft 17 to which the holder is to be attached, gaps 68, 69 functioning to permit tightening the holder halves 70, 71 to the shaft despite tolerance variations in shaft diameter. O-ring groove 94 is provided between the inner walls 85, 86. Split O-ring 112 is positioned in groove 94 for sealing against shaft 17 as shown in Figs. 4 and 5. The outer diameter of the holder halves 70, 71 expands from end wall 90 via tapered wall 92 to a diameter at outer axial wall 96 greater than the opening defined by gland walls 32, 33 but less than the inner diameter of wall 34 of the gland halves. Internally, beyond wall 85 toward end wall 98, the inner diameter of the holder halves 70, 71 is increased in steps. Radial wall 100 extends outwardly from wall 85 to axial wall 102. Radial wall 104 extends outwardly from wall 102 to axial wall 106 which in turn extends to end wall 98. Holes 108 drilled in radial wall 100, shown in Fig. 4, have compression springs 110 mounted therein, springs 110 in an uncompressed state extending to radial wall 104, best shown in Fig. 3. Grooved split holder faces 74, 75 each have a groove 114 of generally square cross section. Groove 114 comprises axially extending segments 116, 120 and an angled segment 118 connecting the end segments 116, 120. Groove segment 116 is positioned at and exposed to the base of O-ring groove 94 and extends completely across and beyond the O-ring groove 94. Groove segment 120 is positioned outwardly of and exposed to axial wall 106, extending thereacross. A straight elastomeric holder gasket 122 of generally square cross-section is deformed and placed in groove 114. Holder gasket 122 projects above groove 114 for sealing contact with a mating ungrooved split face of another holder half. At groove segments 116 and 120, gasket 122 projects, respectively, inwardly beyond the base of O-ring groove 94 for sealing contact with O-ring 112 and inwardly beyond axial wall 106 for sealing contact with O-ring 142. Rotary seal assembly 16 also comprises carbon split rotary seal ring segments, i.e., halves 124, 126, positioned within the holder halves. Rotary seal ring halves have mating irregular split faces 128, 130. The inner diameter of the rotary seal ring halves is greater than the shaft 17 diameter to permit axial motion therealong. A support portion 132 has an outer diameter slightly smaller than that of axial wall 102 of the holder halves 70, 71 and has an end wall 134 engaging the free ends of springs 110 which provide resilient support means axially biasing the rotary seal ring halves 124, 126. A seal portion 136 of the rotary seal ring halves, joined to the support portion 132 at radial wall 138, has an outer diameter within the holder halves slightly smaller than holder wall 106 and projects beyond the holder halves to radially extending flat rotary sealing surface 140. Split O-ring securing means 142 is disposed and fastened about seal ring halves 124, 126 and has sufficient resilience to cause the engagement of irregular split faces 128, 130 of rotary seal ring halves 124, 126 in sealing contact with each other. As shown in Fig. 4, when mechanical seal 10 is assembled, split O-ring 142 is in sealing contact with holder walls 104, 106, and with support portion 132 and wall 138 of seal ring halves 124, 126 providing axial as well as radial support therefor and with springs 110 resiliently supporting the ring halves in spaced relationship to the rigid walls of the holder halves. Of importance to the sealing function of O-rings 112 and 142, holder gasket 122 preferably has a lower hardness e.g., 40-50, than of O-rings 112 and 142, e.g., 60-70. This prevents distortion of the O-rings where they make sealing contact with the gasket. Stationary split seal ring assembly 14, best shown in Figs. 3, 4 and 5, comprises alumina ceramic or silicon carbide split stationary seal ring segments, i.e., halves 150, 151. Stationary seal ring halves have mating irregular split faces 154, 156. The inner diameter of the stationary seal ring halves at wall 157 is greater than the shaft 17 diameter. As shown in Figs. 3 and 4, a support portion 158 has an outer diameter smaller than that of axial wall 36 of the gland halves 11, 12. A seal portion 162 of the stationary seal ring halves, joined to the support portion 158 at radial wall 160, has an outer diameter somewhat smaller than that of gland wall 36 and projects axially therebeyond to radially extending flat stationary sealing surface 164 which sealingly engages flat rotary sealing surface 140. Elastomeric ring boot securing means 170, rectangular in section, is disposed and fastened about split stationary seal ring halves 150, 151 and has sufficient resilience to cause the engagement of irregular split faces 154, 156 in sealing contact with each other. Boot 170 is positioned in sealing contact between gland wall 36 and support portion 158 of stationary seal ring halves 150, 151 and between gland wall 35 and radial wall 160 of stationary seal ring halves 150, 151. The axial dimension of boot 170 is greater than that of support portion 158 of stationary seal ring halves 150, 151 between radial wall 160 and end wall 165 thereby spacing end wall 165 axially away from gland radial wall 35 and providing resilient support means for the stationary seal ring halves 150, 151. The hardness of boot 170 is greater, e.g., 60-70, than that of gland gasket 50, e.g., 40-50, to avoid distortion of boot 170 at the point of sealing contact with gasket 50. As generally illustrated in Fig. 3, identical ball and socket fastening mechanisms are provided on the free ends of split O-rings 112 and 142, and of ring boot 170. In greater detail with reference to O-ring 112, as shown in Fig. 6, at one end, O-ring 112 narrows to substantially hemispherical shoulder portion 222 and, adjacent thereto, annular neck portion 224. Immediately adjacent neck portion 224 is substantially spherical head portion 226. In fastening, head portion 224 is inserted into matching spherical socket portion 227 at the other end of O-ring 112 such that annular collar portion 228 surrounds and captures neck portion 224, and shoulder portion 222 is in intimate contact with annular jacket portion 230. Manufacture In manufacturing the gland halves 11, 12 and the holder halves 70, 71 a blank is cut in half. Alternatively, blanks for the gland halves and the holder halves may be cast. The halves are then joined and final internal diameters are then machined on conventional equipment. In the case of the holder halves, shims are used between the halves when they are joined to assure concentricity while controlling clearance gaps 68, 69 therebetween. Rotary seal ring halves 124, 126 and stationary seal ring halves 150, 151 are split from whole rings finished to final dimensions before splitting. Rotary sealing surface 140 and stationary sealing surface 164 are each lapped to a flatness of 0.12µm (two helium light bands). Thereafter the rings are split using the same technique. In greater detail with reference to the stationary ring and referring to Figs. 7 and 8, the finished whole ring is first filed to form two axially extending V-shaped notches, 240, 242, 180° apart, on the inside wall 157 thereof. The ring is then placed on two movable segments 246 of an expandable arbor 244 with notches 240, 242 oriented 90° away from segments 246. As the arbor 244 is operated normally, segments 246 move radially outwardly against the ring causing the ring to split into ring halves 150, 151 at notches 240, 242. The fracture creates mating irregular split faces 154, 156. Advantageously, when the mating irregular faces are placed together, precise matching occurs without distortion of the finished dimensions. Assembly and Operation The tightening of gland cap screws 28 clamps stationary split seal assembly 14 to the gland formed by gland halves 11, 12. Thus, when seal 10 is mounted to a pump or the like, the gland and the stationary split seal assembly are held stationary. The tightening of holder cap screws 78 clamps rotary split seal assembly 16 to shaft 17; and holder assembly 18 then drives rotary seal assembly 16 with shaft 17. As illustrated in Fig. 4 the holder 18 is mounted on shaft 17 in a position spaced from tapered gland wall 33, such that O-ring 142 is seated between holder walls 104, 106 and opposing walls 138, 132 of rotary seal ring halves 124, 126. Springs 110 and split O-ring 142 resiliently support the seal halves 124, 126 in spaced relationship to the walls of the holder halves 70, 71 and permit small radial and axial "floating" movements of rotary seal halves 124, 126 with respect to shaft 17 while still permitting rotary sealing surface 140 to follow stationary sealing surface 164. In operation, under fluid pressure, seal 142 may move away from wall 138 in which case axial resilient support is provided solely by springs 110. Because rotary seal halves 124, 126 "float", and are not held rigidly by holder assembly 18, neither end wall 134 nor any portion of the holder is lapped. Similarly, the resilient support of stationary seal ring halves 150, 151 by ring boot 170, resiliently supporting the seal halves 150, 151 in spaced relationship to the walls of the gland halves 11, 12, makes it unnecessary to lap back end wall 165. The spacing of stationary seal ring halves 150, 151 away from gland wall 35 permits the halves to float and move slightly in response to force transferred from rotary seal halves 124, 126. Thus, surfaces 140, 164 are self aligning as a result of the floating action. The rotary and stationary seal ring halves 124, 126 and 150, 151, respectively, are held together by O-ring 142 and boot 170 compressed against walls 106 and 36. Advantageously, hydraulic pressure of fluid within chamber 19, exerted against the exterior walls of the ring halves at seal portions 136, 162, provides an additional force, proportional to the fluid pressure, holding the ring halves together. O-ring 112 seals fluid flow along shaft 17 past rotary seal assembly 16. O-ring 142 and boot 170 seal fluid flow from chamber 19 past the rotary and stationary seal assemblies 16, 14, respectively, while flat seal surfaces 140, 164 seal between the relatively moving assemblies 14, 16. Holder gaskets 122 compressed between holder halves 70, 71 seal fluid flow from chamber 19 past the gaps 68, 69 between the holder halves 70, 71. In addition, sealing is enhanced by increasing fluid pressure exerted on gaskets 122 from chamber 19 through gaps 68, 69. Gaskets 122 overlying O-rings 112, 142 provide sealing contact against the O-rings, enhanced by fluid pressure, while the difference in hardnesses of the gaskets 122 and O-rings 112, 142 assures that the O-rings remain undistorted. Gaskets 122 have a length such that they extend beyond the holder halves 70, 71 to and overlie the seal portions 136 of rotary seal ring halves 124, 126 prior to assembly on a shaft; thus during assembly, after rotary seal assembly 16 is secured to shaft 17, there is no tendency for gasket 122 to be distorted out of position by O-ring 142 or wall 138 of the rotary seal ring halves 124, 126 as the gland is moved for fastening to mounting surface 60. Gland gaskets 50 are compressed between gland halves 11, 12 to seal fluid flow from chamber 19 past the gland halves. Any fluid pressure resulting from any leakage between the gland halves increases the sealing effect of the gland gasket elsewhere along its length and particularly of segment 56 against boot 170 and segment 54 against face gasket 58. Other Embodiments An alternative embodiment of the invention is illustrated in Fig. 9. Reference numerals having an apostrophe appended thereto, either in Fig. 9, the text, or the claims, indicate structural elements of the alternative embodiment which are analogous to the structural elements set forth and described above. Like the embodiment previously described, that of Fig. 9 comprises a seal gland 12' defining a seal chamber 19' housing stationary and rotary split seal ring assemblies 14', 16'. The most significant difference of the embodiment illustrated in Fig. 9 is that the spring biased seal ring assembly 14', biased by springs 110', is the stationary seal. The other seal ring assembly 16', secured by boot 170', is mounted in a holder 18', boot 170' spacing end wall 165' of seal assembly 16' away from the facing radially extending wall 100' of holder 18'.

Claims: Split mechanical face seal (10) comprising a seal gland comprised of gland halves (11, 12; 11', 12') fastened together and defining a chamber (19; 19') therewithin, a pair of seal ring assemblies (14, 16; 14', 16'), each said ring assembly comprising a rigid seal ring of split ring segments (124, 126, 150, 151; 124', 126', 150', 151') and each said seal ring having a flat radially extending sealing surface (140, 164; 164', 140'), the sealing surfaces of said rings being in sealing contact with each other, a respective securing means (142, 170; 142', 170') extending about the outer circumference of each said seal ring holding said ring segments thereof together, said seal rings are axially supported in said seal (10) by support means (110, 170; 110', 170'); the seal ring of one of said seal ring assemblies (14; 14') is supported in said gland in said chamber (19; 19') and the other of said seal ring assemblies (16; 16') comprises a holder (70, 71; 70', 71'), comprising holder components (70, 71; 70', 71') fastened together and adapted to be connected to, and supported within said chamber (19; 19'), on a shaft (17; 17') extending into said chamber (19; 19'), and supporting the seal ring of said other of said seal ring assemblies (16; 16') within said holder (70, 71; 70', 71') for rotation with said shaft (17; 17'); one of said securing means (142, 170') comprising an elastomeric split member sealingly engaging opposed surfaces of said seal ring (16, 16') and said holder (70, 71; 70', 71'); said support means (110, 170; 110', 170') comprising resilient members (110, 170; 110', 142') contacting and supporting each said seal ring axially on a side (134, 160; 134', 160') opposite the sealing surface (140, 164; 140', 164') thereof, respectively ; one said resilient member (170; 142') preferably comprising an elastomeric split member, and the other said resilient member (110, 110') comprising biasing means (110; 110'), preferably comprising compression springs , axially resiliently biasing one of said seal rings against the other of said seal rings for urging said sealing surfaces (140, 164; 164', 140') thereof together, said holder (70, 71; 70', 71') and said gland comprising rigid walls (35, 100; 35', 100'), for contact with respective ones of said support means (110, 170; 110', 142'), characterized in that said holder (70, 71; 70', 71') is split , and said holder components are holder halves , said support means (110, 170; 110', 142') is resilient and non rigidly supports said split ring segments (124, 126, 150, 151; 124', 126', 150', 151') resiliently , radially as well as axially, and in spaced relation from all adjacent walls of said gland and said holder (70, 71; 70', 71'), permitting floating motion in all directions of said split ring segments (124, 126, 150, 151; 124', 126', 150', 151') and self-alignment of same. Split seal of claim 1, characterized in that said support means (170; 142') sealingly engage opposed surfaces of said seal ring (14; 14') and said gland (11, 12; 11', 12'). Split seal of claim 1 or 2, characterized in that axially extending walls (136, 162; 136', 162') of said seal rings are at least partially exposed about their outer circumference to said chamber (19; 19') whereby said ring segments are adapted to be held together more firmly by fluid pressure in said chamber. Split seal of any of the preceding claims, characterized in that said compression springs (110; 110') extend between said holder (70, 71; 70', 71') and said seal ring (124, 126; 124', 126') supported in said holder. Split seal of any of the preceding claims, characterized in that said elastomeric member (142; 170') supporting said seal ring (124, 126; 170', 171') in said holder (70, 71; 70', 71') sealingly engages radial and axial walls (104, 106; 10 0 ' 106') of said holder and at least an axial wall (132; 158') of said seal ring in said holder against fluid flow therebetween, an elastomeric member (112; 112') is provided in a groove (94; 94') on the interior of said holder for fluid sealing engagement with a shaft (17; 17'), said holder halves (70, 71; 70', 71') comprise opposed split faces (72, 75, 73, 74; 72', 75', 73', 74'), and an elastomeric holder gasket (122; 122') extends between each pair of split faces of said holder halves, each said gasket (122; 122') exposed in sealing contact with and having a lower hardness than said elastomeric members (142, 112; 170', 112') supporting said seal ring in said holder and provided in said groove on the interior of said holder. Split seal of claim 5, characterized in that said holder halves (70, 71; 70', 71') are spaced apart forming gaps (68, 69; 68', 69') therebetween at said split faces, a groove (114; 114') is positioned in one holder split face (74, 75; 74', 75') of each pair of faces and one said holder gasket (122; 122') is positioned in each groove (114; 114') extending thereabove and across the said gap between said faces and in sealing contact with the holder face (72, 73; 72', 73') opposing said groove (114; 114') of said one holder face (74, 75; 74', 75'). Split seal of claim 6, characterized in that said grooves (114; 114') in said holder faces and said holder gaskets (122; 122') therein are positioned radially outwardly of and exposed to said groove (94; 94') on the interior of said holder and said elastomeric member (112; 112') therein and to said elastomeric member (142; 170') supporting said seal ring in said holder. Split seal of any of the preceding claims, characterized in that said elastomeric member (170; 142') supporting said seal ring (150, 151; 124', 126') in said seal gland (11, 12; 11', 12') sealingly engages at least one of the radial and axial walls (35, 36; 35', 36') of said gland and at least an axial wall (158; 132') of said seal ring in said gland against fluid flow therebetween, said gland halves (11, 12; 11', 12') comprise opposed split faces (20, 21, 22, 23; 20', 21', 22', 23'), and an elastomeric gland gasket (50; 50') extends between each pair (20, 22, 21, 23; 20', 21', 22', 23') of split faces of said gland halves, each said gland gasket (50; 50') exposed in sealing contact with and having a lower hardness than said elastomeric member (170; 142') supporting said seal ring in said gland. Split seal of claim 8, characterized in that a groove (40; 40') is positioned in one gland split face (22, 23; 22', 23') of each pair of faces and one said gland gasket (50; 50') is positioned in each groove in sealing contact with the gland face (20, 21; 20', 21') opposing said groove (40; 40') of said one gland face. Split seal of claim 9, characterized in that said grooves (40; 40') in said gland faces and said gland gaskets (50; 50') therein are positioned radially outwardly of and exposed to said elastomeric member (170; 142') supporting said seal ring in said gland. Split seal of claim 10, characterized in that said groove (40; 40') in each gland face (22, 23; 22', 23') and said gland gasket (50; 50') therein each comprise a major segment (42, 52; 42', 52') extending axially between end walls (30, 32; 30', 32') of said gland, said major segment reversed radially inwardly upon itself at one end in a U-shaped configuration defining a further segment (56; 56') exposed to said elastomeric member (170; 142') supporting said seal ring in said gland, said further segment (56; 56') of gland gasket In sealing contact therewith. Split seal of claim 1, characterized in that one said elastomeric member (142; 170') is seated between the holder halves (70, 71; 70', 71') and said ring segments (124, 126; 150', 151') associated therewith, said associated ring segments forming a rotor ring, and the other said elastomeric member (170; 142') is seated between the gland halves (11, 12; 11', 12') and said ring segments (150, 151; 124', 126') associated therewith, the latter of said associated ring segments forming a stator ring, said other said elastomeric member (170; 142') resiliently supporting said stator ring in spaced relationship to walls of said gland, such resilient support of said rings comprising means for permitting slight floating movement of one of said rings in response to force transferred from the other of said rings, said sealing surfaces of said rings being self-aligning with said floating movement. Split seal of claim 1, characterized in that the outer circumference of at least one of said rings is defined by a circumferential axial seal portion (162; 162') at an outer diameter of said ring, said sealing surface (164; 164') and said side (160; 160') opposite of said sealing surface (164; 164') of said ring both extend radially to and terminate at said circumferential axial seal portion. Split seal of claim 13, characterized in that said gland (11, 12; 11', 12') and holder (18; 18') comprise rigidly walled means for housing said seal rings, with compression springs (110; 110') interposed between said rigidly walled means and said side (134; 134') opposite the sealing surface (140; 140') of said resiliently biased ring (16; 14') for biasing said sealing surface of said ring segments (124, 126; 124', 126') thereof axially into said sealing surface of the segments (150, 151; 150', 151') of the other said ring.

Inventors: AZIBERT HENRI V, AZIBERT, HENRI V.
Applicants: CHESTERTON A W CO, A.W. CHESTERTON COMPANY
Application year: 1985
Main classification: F16J15
IPC codes: F04D29, F16J15