CA1326050C - Cast gasket - Google Patents
Cast gasketInfo
- Publication number
- CA1326050C CA1326050C CA 549536 CA549536A CA1326050C CA 1326050 C CA1326050 C CA 1326050C CA 549536 CA549536 CA 549536 CA 549536 A CA549536 A CA 549536A CA 1326050 C CA1326050 C CA 1326050C
- Authority
- CA
- Canada
- Prior art keywords
- gasket
- main body
- body portion
- web
- pipe
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L5/00—Devices for use where pipes, cables or protective tubing pass through walls or partitions
- F16L5/02—Sealing
- F16L5/10—Sealing by using sealing rings or sleeves only
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Underground Structures, Protecting, Testing And Restoring Foundations (AREA)
- Sewage (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A novel cast, resiliently-deformable gasket is provided herein for supporting a sewer pipe in a manhole opening and sealing the space between the walls of the opening and the surface of the sewer pipe. The gasket includes a generally-pentagonally-shaped, relative large mass and substantial thickness main body portion. A cylindrical flange member is integral with the main body portion and is in the form of a staight leg portion terminating in an "L"-shaped foot. A web of substantial thickness but which is nevertheless of less thickness than that of the main body portion. extends radially-inwardly at an acute angle from the main body portion. The web terminates in a rim portion of torroidal form, which is integral with the web and having an inner diameter less than the outer diameter of the pipe. The cylindrical flange and at least half the mass of the main body portion are adapted to be secured in situ within the manhole at the manhole opening. This gasket is sufficiently resilient to compensate for stress in shear, is sufficiently flexible to accomodate extensive misalignment of the sewer pipe, and yet is capable of affording an absolute fluid-tight seal in the rim of the manhole opening. The torroidal rim provides a sealing tension where it contacts the sewer pipe. The gasket moreover is easy to install, comparatively inexpensive to make, and extremely reliable in use,
A novel cast, resiliently-deformable gasket is provided herein for supporting a sewer pipe in a manhole opening and sealing the space between the walls of the opening and the surface of the sewer pipe. The gasket includes a generally-pentagonally-shaped, relative large mass and substantial thickness main body portion. A cylindrical flange member is integral with the main body portion and is in the form of a staight leg portion terminating in an "L"-shaped foot. A web of substantial thickness but which is nevertheless of less thickness than that of the main body portion. extends radially-inwardly at an acute angle from the main body portion. The web terminates in a rim portion of torroidal form, which is integral with the web and having an inner diameter less than the outer diameter of the pipe. The cylindrical flange and at least half the mass of the main body portion are adapted to be secured in situ within the manhole at the manhole opening. This gasket is sufficiently resilient to compensate for stress in shear, is sufficiently flexible to accomodate extensive misalignment of the sewer pipe, and yet is capable of affording an absolute fluid-tight seal in the rim of the manhole opening. The torroidal rim provides a sealing tension where it contacts the sewer pipe. The gasket moreover is easy to install, comparatively inexpensive to make, and extremely reliable in use,
Description
- 1 1326~0 This invention relates to the provision of a new form of cast resiliently-deformable gasket particularly useful for resiliently supporting a sewer pipe in an openin~ through the wall of a manhole. It also provides a tight seal, closing the space between the wall of the openin& and the pipe.
Extruded gaskets are very well adapted for use with sewer pipe of substantial size. Prior known such gaskets generally had a hollow nose section integral with a base member, which latter was embedded in the concrete lining the opening, through which lo the pipe passes. Such gaskets were generally made by cutting a length of the lineal extrusion to a size corresponding to the circumference of the pipe, curving it into the form of a cylinder, uniting the ends, and then flattening the wall so as to produce a disk-like washer. That washer had to be held against considerable internal stress until the concrete had set. In producing gaskets of relatively small diameter, say 4" or 6", the strains involved in constraining the cylinder tubular gasket into a disk-like shape were so great as to limit the use of the small-diameter sizes.
; 20 It had previously been proposed to use molded gaskets of elastomeric material, which were shaped like an ordinary washer, that is, shaped as an apertured disk lying in a single plane.
Such molded washers were embedded in concrete about their outer margin, and lay normal to the axis of the pipe, They were subject to the disadvantage that the elastomer used had limited J
,; ~L
Extruded gaskets are very well adapted for use with sewer pipe of substantial size. Prior known such gaskets generally had a hollow nose section integral with a base member, which latter was embedded in the concrete lining the opening, through which lo the pipe passes. Such gaskets were generally made by cutting a length of the lineal extrusion to a size corresponding to the circumference of the pipe, curving it into the form of a cylinder, uniting the ends, and then flattening the wall so as to produce a disk-like washer. That washer had to be held against considerable internal stress until the concrete had set. In producing gaskets of relatively small diameter, say 4" or 6", the strains involved in constraining the cylinder tubular gasket into a disk-like shape were so great as to limit the use of the small-diameter sizes.
; 20 It had previously been proposed to use molded gaskets of elastomeric material, which were shaped like an ordinary washer, that is, shaped as an apertured disk lying in a single plane.
Such molded washers were embedded in concrete about their outer margin, and lay normal to the axis of the pipe, They were subject to the disadvantage that the elastomer used had limited J
,; ~L
- 2 - 1 3 2 6 ~ ~0 stretch in a radially-outward direction. That is, even though it could be made with an undersized hole, so that the pipe will stretch the material on being inserted, the amount of stretch was not sufficient, in the plane of the gasket, to provide enough freedom for distortion to preserve a tight seal.
The shear stress imposed on sewer pipe passing through a manhole opening may be very severe indeed, and sometimes, even though extremely rare, it was sufficient to break the pipe right off. That eventually was very serious indeed. If the load, lo including not only the weight of the pipe and its contents, but also that imposed by fill, traffic stress, and vibration, is great, the pipe will be driven down into the inner edge of the rubber in the lower part of the gasket - that is, directly under the pipe - and the amount of compression may be sufficient to cause the top of the pipe to pull away from the inner upper edge of the gasket, thus leaving a small but ruinous lunar opening between the gasket and pipe. If the elasticity of the elastomeric material was 6elected to be sufficient to ensure that its upper rim will follow the pipe even under the stress conditions stated, it would probably be so "tight" that insertion of the pipe would be practically impossible. This factor is important, for the choice of elastomeric material is limited. The ASTM specifications for rubber gasketed sewer pipe are quite strict. The elastomer usually conforms to ASTM 443, SBR 1200, or to ASTM 361, Polystyrene, TS 2400.
i _ 3 _ 1326~
If the embedded por~ions of the gasket are planar and extend in a normal direction away from the pipe, they may be pulled ri~ht out of the concrete in which they are embedded, under stress of axial movement of the pipe.
Among the prior patented gaskets to solve this problem are the following Canadian Patents:
1. No. 964,043, issued March 11, 1975, APPARATUS FOR
FABRICATING A PIPE JOINT SEALING DEVICE, Granted to Harry W. Skinner;
2. No. 971,997, issued July 29, 1975, GASKET SEAL BETWEEN
SEWER PIPE AND MANHOLE OPENING, Granted to John Ditcher;
The shear stress imposed on sewer pipe passing through a manhole opening may be very severe indeed, and sometimes, even though extremely rare, it was sufficient to break the pipe right off. That eventually was very serious indeed. If the load, lo including not only the weight of the pipe and its contents, but also that imposed by fill, traffic stress, and vibration, is great, the pipe will be driven down into the inner edge of the rubber in the lower part of the gasket - that is, directly under the pipe - and the amount of compression may be sufficient to cause the top of the pipe to pull away from the inner upper edge of the gasket, thus leaving a small but ruinous lunar opening between the gasket and pipe. If the elasticity of the elastomeric material was 6elected to be sufficient to ensure that its upper rim will follow the pipe even under the stress conditions stated, it would probably be so "tight" that insertion of the pipe would be practically impossible. This factor is important, for the choice of elastomeric material is limited. The ASTM specifications for rubber gasketed sewer pipe are quite strict. The elastomer usually conforms to ASTM 443, SBR 1200, or to ASTM 361, Polystyrene, TS 2400.
i _ 3 _ 1326~
If the embedded por~ions of the gasket are planar and extend in a normal direction away from the pipe, they may be pulled ri~ht out of the concrete in which they are embedded, under stress of axial movement of the pipe.
Among the prior patented gaskets to solve this problem are the following Canadian Patents:
1. No. 964,043, issued March 11, 1975, APPARATUS FOR
FABRICATING A PIPE JOINT SEALING DEVICE, Granted to Harry W. Skinner;
2. No. 971,997, issued July 29, 1975, GASKET SEAL BETWEEN
SEWER PIPE AND MANHOLE OPENING, Granted to John Ditcher;
3. No. 996.150, issued 76/08/31, GASKET SEAL BETWEEN SEWER
PIPE AND MANNOLE OPENING, Granted to John Ditcher;
PIPE AND MANNOLE OPENING, Granted to John Ditcher;
4. No. 1,018,331, issued 77/10/04, METHOD OF MANUFACTURE
OF MANHOLES WITH RESILIENT SeALS, Granted to Ronald E.
Yoakum;
OF MANHOLES WITH RESILIENT SeALS, Granted to Ronald E.
Yoakum;
5. No. 1,077,692, issued 80/05/20, GASKET SEAL BETWEEN
SEWER PIPE AND MANHOLE OPENING, Granted to A-Lok Products Corporation;
SEWER PIPE AND MANHOLE OPENING, Granted to A-Lok Products Corporation;
6. No. 1,079,993, issued 80/06/24, MANHOLE SEAL AND METHOD
OF INSTALLATION THEREFOR, Granted to Vibrapipe Concrete Products Ltd.-Les Produits de Breton Vibrapipe Limitee;
OF INSTALLATION THEREFOR, Granted to Vibrapipe Concrete Products Ltd.-Les Produits de Breton Vibrapipe Limitee;
7. No. 1,085,889, issued 80/09/16, GASKET SeAL BETWEeN
SEWER PIPE AND MANHOLE OPENING, Granted to A-Lok Products Corporation;
1326~0 8. No. 1,100,547, issued 81/05/05, MANHOLE SEAL AND METHOD
OF INSTALLATION THEREFOR, Granted to Vibrapipe, Division of Bestpipe limited;
SEWER PIPE AND MANHOLE OPENING, Granted to A-Lok Products Corporation;
1326~0 8. No. 1,100,547, issued 81/05/05, MANHOLE SEAL AND METHOD
OF INSTALLATION THEREFOR, Granted to Vibrapipe, Division of Bestpipe limited;
9. No, 1,112,468, issued 81/11/17, METHOD AND APPARATUS
FOR INSTALLING A GASKET IN THE PERIPHERAL WALL OF AN
OPENING IN A M~SONRY WALL, Gran~ed to Casauton Inc.
FOR INSTALLING A GASKET IN THE PERIPHERAL WALL OF AN
OPENING IN A M~SONRY WALL, Gran~ed to Casauton Inc.
10. No. 1,169,837, issued 84/06l26, PIPE SeAL, Granted to William D. Jones;
In particular, Canadian Patent 1,073,938 issued May 18, 1980 to A-Lok Products Corporation, and its corresponding U.S. Patent 4,103,901 patented August 1, 1978 provided a molded gasket for resiliently supporting a sewer pipe in a manhole opening, while sealing the opening against fluid flow. The patented gasket was a molded annulus of elastomeric material having a peripheral flange of substantial width and thickness connected by a radially extending web to an inner concentric rib of greaeer width than said web, The flange was adapted to be embedded in concrete to its radially inward face. The rib had an integral circular skirt extending ir,wardly therefrom in a non-radial direction, and was united at its rim with a second circular skirt oriented thereto at a reverse angle. The second skirt merging throughout its periphery into an O-rin8 of slightly smaller diameter than the diameter of the sewer pipe it is adapted to surround. Another embodiment of such molded elastomeric gasket was of circular shape having an inner toroidal portion adapted closely to embrace _ 5 _ 1326~50 a pipe, the portion being of substantially smaller inner diameter than the outer diameter of the pipe, The gasket had an outer peripheral flange9 T-shaped in section, adapted to be fixedly anchored in settable ma~erial lining an opening in a manhole wall, with the base of the T lyin~ radially inward of its head portion, The toroidal portion merged tangentially with an integral inner skirt portion, The outer flange merged, a~ the base of the T, with an outer skirt portion, the inner edge of the outer skirt being integrally ~oined to the outer edge of the inner skirt, the whole being characterized in that the combined width of the skirt portions is greater than the distance between the toroidal portion and the base of the T-shaped flange.
Other patented gaskets include the following U,S. Patents:
1, 4,084,827 patented April 18, 1978 by Franz-Joseph Wolf, which taught a ~oint for pipes made of mineral materials comprising a pipe, a sleeve to receive the pipe, and a gasket ring carried by the sleeve, The gasket ring comprised a guard ring and a flange ring, the ~uard ring being mounted in an annular tee-slot of the sleeve and the flange ring pro~ecting radially into the sleeve, The sleeve was provided with an inwardly-pro~ecting inversion ring and with an annular chamber following the tee-slot, respectively to pivot the guard ring and then to receive it, when a pipe was inserted.
2, 4,333,662 patented June 8, 1982 by William D. Jones, which taught a gasket which was particularly suited for sealing - 6 - 1 3 2 6 0~ 0 the annular space between a pipe and a port in an underground structure is disclosed. The gasket comprised a hollow annular ring which surrounded the pipe and was connected by a narrow neck to a base at least partially embedded in the underground structure. The base had means extending around its outer periphery to mount the seal securely in the manhole and to provide a block against water seepage across the periphery of the gasket.
and 3. 4,387,900 patented June 14, 1983 by A-Lok Products, Inc., which taught a resilient gasket having an outer annular flange positioned with a manhole opening and maintained thereagainst under compression by means of a compression band.
The gasket was provided with a central opening defined by an ; enlarged beaded periphery having an elasticity adapted to tightly encircle the outer periphery of the pipe. A folded intermediate section was arranged between and integrally ~oined to the outer flange and the beaded inner periphery. The intermediate section was comprised of first and second diagonally-aligned annular portions integrally ~oined along a fold to define a V-shape, which imparted a yieldability enabling the gasket to maintain a watertight seal between the manhole openin~ and the pipe, even in the presence of a significant misalignment section of the gasket ad~acent the inner beaded periphery to enhance the watertight ~ seal between the gasket and the pipe. The compression band could ; be provided with pairs of substantially V-shaped slots which - 7 _ 1 32 g ~ ~
enabled the band to assume a curvature in a direction transverse to the curved periphery in order to conform to the curvature of the manhole opening. The clamping band was formed of a material which was impervious to the surrounding environment and had a gap, and a segment hingedly connected to the main body thereof for placement in the gap and against the interior surface of the gasket to lock the compression band in position and maintain the gasket flange under compression, Many of the above-identified gaskets had certain disadvantages, among which were the following:
a) they allowed only very limited inclination of the sewer pipe with respect to its normal axis perpendicular to the plane of the manhole opening;
b) they did not seal completely round the pipe when the latter is sub~ected to an abnormally high shearing ~tress;
c) the pipe once inserted into the manhole opening often could not be withdrawn for inserting it~ outer end into the bell-shaped spigot connection of the ad~acent sewer pipe wlthout breakage of the gasket; and d) a poor seal often effected around the pipe due to surface irregularities of the pipe surface.
In an attempt to solve those and other problems, Gilbert, in Canadian Patent 1,207,815 issued July 15, 1986, proposed an annular elastomeric gasket for resiliently supporting a sewer pipe in a manhole opening and sealin8 the space between the --` i326~0 opening surface and the surface of the pipe. The gasket, when in unstressed state, had an outer cylindrical flange member extending axially on both sides of a midplane which was normal to the axis of the pipe. It included a web extending radially-inwardly from a midsection of the inner surface of the cylindrical flange member and integral therewith, the web and the flange being adapted for embedment in settable material lining the manhole opening. An enlargement extended radially-inwardly from the web to form a sealing ridge proximate to the web which lo laterally protruded from one side face of the web, The enlargement defined a generally-flat lateral surface merging with the sealing ridge and radially inwardly extending therefrom and tapering from the ridge towards the midplane, and a sealing lip depending from the radially inner end portion of the enlargement, extending at generally right angle to the midplane and laterally protrudlng from the lateral surface. The lip had a lateral surface of the enlargement. The lip alco had an inner diameter substantially less than the outer diameter of the pipe, The sealing ridge and the sealing lip were adapted to contact the 2~ external surface of the pipe at two axially spaced zones with the two lateral surfaces defining an annular void therebetween.
That patentee also proposed, as a new article of manufacture the combination of the gasket with its cylindrical flange member and web embedded in a channel formed at the opening surface with the opening surface defining two frusto-conical surface portions 9 1326~0 extending on opposite sides of the channel and web with a first frusto-conical surface portion disposed on the side of the lip and sealing ridge and having a minimum diameter which is less than the minimum diameter of the other frusto-conical surface portion.
Even the above discussed gaskets did not entirely solve the above-referred to problems. Consequently, an ob~ect of a broad aspect of this invention is to provide a molded elastomeric gasket which would provide a firm support for the pipe, which is lo sufficiently resilient to compensate for stress in shear, sufficiently flexible to accommodate extensive misalignment of the pipe, and yet capable of affording an absolute fluidtight seal in the rim of the opening, and still further which is easy to install, comparatively inexpensive to make, and extremely reliable in use.
It is an obJect of another aspect of the present invention to provide such a gasket which can effect a seal at two longitudinally spaced zones around the pipe to effect a double seal.
An ob~ect of still another aspect of the present invention is to provide such a gasket which would permit an inclination of the pipe within the manhole opening without destroying the sealing effect of the gasket.
An ob~ect of yet another aspect of the present invention resides in such a gasket which would allow the pipe to be shifted - 1326~
in both axial directions with respect to the gasket without damaging the latter.
An ob~ect of a still further aspect of the invention is to provide an assembly of a wall having an opening for receiving a pipe with the surface of the wall opening being non-symmetrical on each side of the gasket so as to form a step positively to limit lateral displacement of the pipe under ~bnormally high shearing force so as to provide a good seal around the pipe even under such a force.
By one broad aspect of this invention, a cast, resiliently-deformable gasket is provided for supporting a sewer pipe in a manhole opening and sealing the space between the walls of the opening and the surface of the sewer pipe, the gasket comprising:
(a) a generally-pentagonally-shaped, relatively-large mass and æubstantial thickness main body portion; (b) a cylindrical flange member in the form of a straight leg portion terminating in an "L"-shaped foot, the cylindrical flange member being integral with the main body portion; and (c), a web of substantial thickness, but which is nevertheless of less thickness than that of the main body portion, extending radially-inwardly at an acute angle from the main body portion, the web terminating in a rim portion of torroidal form, which rim portion is integral with the web and which has an inner diameter less than the outer diameter of the pipe; the cylindrical flange and at least half the mass of the main body portion being adapted to be secured in situ within the manhole at the manhole opening.
' ~' - 11 1326~`0 In such cast gasket, it is preferred that the acute angle at which the web extends radially-inwardly be 45. The torroidal rim preferably is of a diameter at least twice the thickness of such web, By another aspect of this invention, a new article of manufacture is provided, by the combination of (I) a manhole having an opening therein; and (II) a cast, resiliently-deformable gasket secured _ situ within the manhole opening, the gasket supporting a sewer pipe in the manhole opening and sealing lo the space between the walls of the opening and the surface of the sewer pipe, the gasket comprising: (a), a generally-pentagonally-shaped, relatively-large mass and substantial thickness main body portion; (b), a cylindrical flange member which is integral with the main body portion and which is in the form of a staight leg portion terminating in an "L"-shaped foot; and (c), a web of substantial thic~ness but which is nevertheless of less thickness than that of the main body portion, extending radially-inwardly at an acute angle from the main body portion, the web terminating in a rim portion of torroidal form, which is integral with the web and having an inner diameter less than the outer diameter of the pipe; the cylindrical flan~e and at least half the mass of the main body portion being secured _ situ within the manhole at the manhole opening.
In the accompanying drawings, Figure 1 is a perspective view of a manhole, with a sewer ' pipe extending thereinto;
.~, . .
;
In particular, Canadian Patent 1,073,938 issued May 18, 1980 to A-Lok Products Corporation, and its corresponding U.S. Patent 4,103,901 patented August 1, 1978 provided a molded gasket for resiliently supporting a sewer pipe in a manhole opening, while sealing the opening against fluid flow. The patented gasket was a molded annulus of elastomeric material having a peripheral flange of substantial width and thickness connected by a radially extending web to an inner concentric rib of greaeer width than said web, The flange was adapted to be embedded in concrete to its radially inward face. The rib had an integral circular skirt extending ir,wardly therefrom in a non-radial direction, and was united at its rim with a second circular skirt oriented thereto at a reverse angle. The second skirt merging throughout its periphery into an O-rin8 of slightly smaller diameter than the diameter of the sewer pipe it is adapted to surround. Another embodiment of such molded elastomeric gasket was of circular shape having an inner toroidal portion adapted closely to embrace _ 5 _ 1326~50 a pipe, the portion being of substantially smaller inner diameter than the outer diameter of the pipe, The gasket had an outer peripheral flange9 T-shaped in section, adapted to be fixedly anchored in settable ma~erial lining an opening in a manhole wall, with the base of the T lyin~ radially inward of its head portion, The toroidal portion merged tangentially with an integral inner skirt portion, The outer flange merged, a~ the base of the T, with an outer skirt portion, the inner edge of the outer skirt being integrally ~oined to the outer edge of the inner skirt, the whole being characterized in that the combined width of the skirt portions is greater than the distance between the toroidal portion and the base of the T-shaped flange.
Other patented gaskets include the following U,S. Patents:
1, 4,084,827 patented April 18, 1978 by Franz-Joseph Wolf, which taught a ~oint for pipes made of mineral materials comprising a pipe, a sleeve to receive the pipe, and a gasket ring carried by the sleeve, The gasket ring comprised a guard ring and a flange ring, the ~uard ring being mounted in an annular tee-slot of the sleeve and the flange ring pro~ecting radially into the sleeve, The sleeve was provided with an inwardly-pro~ecting inversion ring and with an annular chamber following the tee-slot, respectively to pivot the guard ring and then to receive it, when a pipe was inserted.
2, 4,333,662 patented June 8, 1982 by William D. Jones, which taught a gasket which was particularly suited for sealing - 6 - 1 3 2 6 0~ 0 the annular space between a pipe and a port in an underground structure is disclosed. The gasket comprised a hollow annular ring which surrounded the pipe and was connected by a narrow neck to a base at least partially embedded in the underground structure. The base had means extending around its outer periphery to mount the seal securely in the manhole and to provide a block against water seepage across the periphery of the gasket.
and 3. 4,387,900 patented June 14, 1983 by A-Lok Products, Inc., which taught a resilient gasket having an outer annular flange positioned with a manhole opening and maintained thereagainst under compression by means of a compression band.
The gasket was provided with a central opening defined by an ; enlarged beaded periphery having an elasticity adapted to tightly encircle the outer periphery of the pipe. A folded intermediate section was arranged between and integrally ~oined to the outer flange and the beaded inner periphery. The intermediate section was comprised of first and second diagonally-aligned annular portions integrally ~oined along a fold to define a V-shape, which imparted a yieldability enabling the gasket to maintain a watertight seal between the manhole openin~ and the pipe, even in the presence of a significant misalignment section of the gasket ad~acent the inner beaded periphery to enhance the watertight ~ seal between the gasket and the pipe. The compression band could ; be provided with pairs of substantially V-shaped slots which - 7 _ 1 32 g ~ ~
enabled the band to assume a curvature in a direction transverse to the curved periphery in order to conform to the curvature of the manhole opening. The clamping band was formed of a material which was impervious to the surrounding environment and had a gap, and a segment hingedly connected to the main body thereof for placement in the gap and against the interior surface of the gasket to lock the compression band in position and maintain the gasket flange under compression, Many of the above-identified gaskets had certain disadvantages, among which were the following:
a) they allowed only very limited inclination of the sewer pipe with respect to its normal axis perpendicular to the plane of the manhole opening;
b) they did not seal completely round the pipe when the latter is sub~ected to an abnormally high shearing ~tress;
c) the pipe once inserted into the manhole opening often could not be withdrawn for inserting it~ outer end into the bell-shaped spigot connection of the ad~acent sewer pipe wlthout breakage of the gasket; and d) a poor seal often effected around the pipe due to surface irregularities of the pipe surface.
In an attempt to solve those and other problems, Gilbert, in Canadian Patent 1,207,815 issued July 15, 1986, proposed an annular elastomeric gasket for resiliently supporting a sewer pipe in a manhole opening and sealin8 the space between the --` i326~0 opening surface and the surface of the pipe. The gasket, when in unstressed state, had an outer cylindrical flange member extending axially on both sides of a midplane which was normal to the axis of the pipe. It included a web extending radially-inwardly from a midsection of the inner surface of the cylindrical flange member and integral therewith, the web and the flange being adapted for embedment in settable material lining the manhole opening. An enlargement extended radially-inwardly from the web to form a sealing ridge proximate to the web which lo laterally protruded from one side face of the web, The enlargement defined a generally-flat lateral surface merging with the sealing ridge and radially inwardly extending therefrom and tapering from the ridge towards the midplane, and a sealing lip depending from the radially inner end portion of the enlargement, extending at generally right angle to the midplane and laterally protrudlng from the lateral surface. The lip had a lateral surface of the enlargement. The lip alco had an inner diameter substantially less than the outer diameter of the pipe, The sealing ridge and the sealing lip were adapted to contact the 2~ external surface of the pipe at two axially spaced zones with the two lateral surfaces defining an annular void therebetween.
That patentee also proposed, as a new article of manufacture the combination of the gasket with its cylindrical flange member and web embedded in a channel formed at the opening surface with the opening surface defining two frusto-conical surface portions 9 1326~0 extending on opposite sides of the channel and web with a first frusto-conical surface portion disposed on the side of the lip and sealing ridge and having a minimum diameter which is less than the minimum diameter of the other frusto-conical surface portion.
Even the above discussed gaskets did not entirely solve the above-referred to problems. Consequently, an ob~ect of a broad aspect of this invention is to provide a molded elastomeric gasket which would provide a firm support for the pipe, which is lo sufficiently resilient to compensate for stress in shear, sufficiently flexible to accommodate extensive misalignment of the pipe, and yet capable of affording an absolute fluidtight seal in the rim of the opening, and still further which is easy to install, comparatively inexpensive to make, and extremely reliable in use.
It is an obJect of another aspect of the present invention to provide such a gasket which can effect a seal at two longitudinally spaced zones around the pipe to effect a double seal.
An ob~ect of still another aspect of the present invention is to provide such a gasket which would permit an inclination of the pipe within the manhole opening without destroying the sealing effect of the gasket.
An ob~ect of yet another aspect of the present invention resides in such a gasket which would allow the pipe to be shifted - 1326~
in both axial directions with respect to the gasket without damaging the latter.
An ob~ect of a still further aspect of the invention is to provide an assembly of a wall having an opening for receiving a pipe with the surface of the wall opening being non-symmetrical on each side of the gasket so as to form a step positively to limit lateral displacement of the pipe under ~bnormally high shearing force so as to provide a good seal around the pipe even under such a force.
By one broad aspect of this invention, a cast, resiliently-deformable gasket is provided for supporting a sewer pipe in a manhole opening and sealing the space between the walls of the opening and the surface of the sewer pipe, the gasket comprising:
(a) a generally-pentagonally-shaped, relatively-large mass and æubstantial thickness main body portion; (b) a cylindrical flange member in the form of a straight leg portion terminating in an "L"-shaped foot, the cylindrical flange member being integral with the main body portion; and (c), a web of substantial thickness, but which is nevertheless of less thickness than that of the main body portion, extending radially-inwardly at an acute angle from the main body portion, the web terminating in a rim portion of torroidal form, which rim portion is integral with the web and which has an inner diameter less than the outer diameter of the pipe; the cylindrical flange and at least half the mass of the main body portion being adapted to be secured in situ within the manhole at the manhole opening.
' ~' - 11 1326~`0 In such cast gasket, it is preferred that the acute angle at which the web extends radially-inwardly be 45. The torroidal rim preferably is of a diameter at least twice the thickness of such web, By another aspect of this invention, a new article of manufacture is provided, by the combination of (I) a manhole having an opening therein; and (II) a cast, resiliently-deformable gasket secured _ situ within the manhole opening, the gasket supporting a sewer pipe in the manhole opening and sealing lo the space between the walls of the opening and the surface of the sewer pipe, the gasket comprising: (a), a generally-pentagonally-shaped, relatively-large mass and substantial thickness main body portion; (b), a cylindrical flange member which is integral with the main body portion and which is in the form of a staight leg portion terminating in an "L"-shaped foot; and (c), a web of substantial thic~ness but which is nevertheless of less thickness than that of the main body portion, extending radially-inwardly at an acute angle from the main body portion, the web terminating in a rim portion of torroidal form, which is integral with the web and having an inner diameter less than the outer diameter of the pipe; the cylindrical flan~e and at least half the mass of the main body portion being secured _ situ within the manhole at the manhole opening.
In the accompanying drawings, Figure 1 is a perspective view of a manhole, with a sewer ' pipe extending thereinto;
.~, . .
;
- 12 - 132~0~ -Figure 2 is a section along the line II-II of Figure 1, showing the cooperation between the gasket of an aspect of this invention and the sewer pipe;
Figure 3 is a perspective view of a portion of the gasket of an aspect of this invention; and Figure 4 i6 an enlarged cross-sectional view of the gasket of an aspect of this invention.
As seen in Figure 1, the manhole 10 is a precast cylindrical member 11 with a concrete sewer pipe 12 extending through an opening 13 therein. The opening 13 is provided with a cast- _-lo situ, cast gasket 14 to be described in greater detail hereinafter~
The unique cooperation of the manhole opening 13 and the gasket 14 in maintaining a seal when sewer pipe 12 i8 inserted therein is shown in Figure 2. Here is seen that the weight of the sewer pipe 12 forces the head 15 and the leg 25 of the gasket 14 into its fully compressed position. Nowever, excess compression is prevented by contact of the sewer pipe 12 at 60 with flattened annulus 61 of the opening 13 where the base of the sloping face 66 intersects the lower portion of the manhole opening 13 and by cooperation with components of the gasket 14 to be described later. It is preferred that face 61 slope at an angle of 2', that face 66 slope at an angle of 20- and that face 67 slope at an angle of 20-. Sealing contact is maintained because of the amount of contact between areas 63 of the sewer pipe 12 and 64 of gasket 14 which includes cooperating components - 13 _ 1 32 6 ~ ~0 of the gasket 14 to be described hereinafter. In addition, the web and the torroidal rim (to be described hereinafter) provide a sealing tension where they contact the sewer pipe 12.
This compression does not result in any transfer of forces to the leg 2~, since (as seen in Figure 4) the forces are absorbed by the compression of the web 24 into the arcuate depression provided by arcuate face 19. Moreover, the lower portion of the body portion 15 as well as the flange 20, i.e. the leg 21 and the foot 22, are encased by the concrete. Thus, the lower portion of the body 15 of the gasket 14 and the entire leg 21 and foot 22 are free from forces which might tend to loosen the gasket 14 from within the concrete of the manhole 11.
Figures 3 and 4 show the cast gasket 14 in greater detail.
The gasket 14 is a cast, elongated, resiliently-deformable, e.g.
elastomeric, for example, rubber, gasket cast as an endless circular form. It consists of a generally-pentagonally-shaped, relative large mass and substantial thickness main body portion 15 having a flat rear face 16 and a composite front face composed of flat face 17 and sloping face 18, sloping at an angle of 45-, to provide an arcuate face 19, Integral with the main body portion 15 is a cylindrical flange member 20 in the form of a straight leg portion 21, coextensive with rear face 16, terminating in an "L"-shaped foot 22. This provides a large volume area 23 to be filled with the concrete at the opening 13 of the manhole 11, r ~
Figure 3 is a perspective view of a portion of the gasket of an aspect of this invention; and Figure 4 i6 an enlarged cross-sectional view of the gasket of an aspect of this invention.
As seen in Figure 1, the manhole 10 is a precast cylindrical member 11 with a concrete sewer pipe 12 extending through an opening 13 therein. The opening 13 is provided with a cast- _-lo situ, cast gasket 14 to be described in greater detail hereinafter~
The unique cooperation of the manhole opening 13 and the gasket 14 in maintaining a seal when sewer pipe 12 i8 inserted therein is shown in Figure 2. Here is seen that the weight of the sewer pipe 12 forces the head 15 and the leg 25 of the gasket 14 into its fully compressed position. Nowever, excess compression is prevented by contact of the sewer pipe 12 at 60 with flattened annulus 61 of the opening 13 where the base of the sloping face 66 intersects the lower portion of the manhole opening 13 and by cooperation with components of the gasket 14 to be described later. It is preferred that face 61 slope at an angle of 2', that face 66 slope at an angle of 20- and that face 67 slope at an angle of 20-. Sealing contact is maintained because of the amount of contact between areas 63 of the sewer pipe 12 and 64 of gasket 14 which includes cooperating components - 13 _ 1 32 6 ~ ~0 of the gasket 14 to be described hereinafter. In addition, the web and the torroidal rim (to be described hereinafter) provide a sealing tension where they contact the sewer pipe 12.
This compression does not result in any transfer of forces to the leg 2~, since (as seen in Figure 4) the forces are absorbed by the compression of the web 24 into the arcuate depression provided by arcuate face 19. Moreover, the lower portion of the body portion 15 as well as the flange 20, i.e. the leg 21 and the foot 22, are encased by the concrete. Thus, the lower portion of the body 15 of the gasket 14 and the entire leg 21 and foot 22 are free from forces which might tend to loosen the gasket 14 from within the concrete of the manhole 11.
Figures 3 and 4 show the cast gasket 14 in greater detail.
The gasket 14 is a cast, elongated, resiliently-deformable, e.g.
elastomeric, for example, rubber, gasket cast as an endless circular form. It consists of a generally-pentagonally-shaped, relative large mass and substantial thickness main body portion 15 having a flat rear face 16 and a composite front face composed of flat face 17 and sloping face 18, sloping at an angle of 45-, to provide an arcuate face 19, Integral with the main body portion 15 is a cylindrical flange member 20 in the form of a straight leg portion 21, coextensive with rear face 16, terminating in an "L"-shaped foot 22. This provides a large volume area 23 to be filled with the concrete at the opening 13 of the manhole 11, r ~
- 14 - 1 3 2 6 ~ 0 Also integral with the main body portion 15 is a web 24 extending inwardly at an angle of 45~, the web 24 being of substantial thickness but which is nevertheless of less thickness than that of the main body portion 15, The web 24 terminates in a rim portion 25 of torroidal form, which torroidal rim 25 is integral with the web 24 and which has an inner diameter less than the outer diameter of the pipe 12.
The cylindrical flange 20 with its leg 21 and foot 22 and at least half the mass of the main body portion 15 is adapted to be secured _ situ within the manhole 11 at the manhole opening 13.
Because of this particular structure, the gasket is sufficiently resilient to compensate for stress in shear, is sufficiently flexible to accomodate extensive misalignment of the sewer pipe, and yet is capable of affording an absolute fluid-tight seal in the rim of the manhole opening. The torroidal rim provides a sealing tension where it contacts the sewer pipe. The gasket moreover is easy to install, comparatively inexpensive to make, and extremely reliable in use.
The cylindrical flange 20 with its leg 21 and foot 22 and at least half the mass of the main body portion 15 is adapted to be secured _ situ within the manhole 11 at the manhole opening 13.
Because of this particular structure, the gasket is sufficiently resilient to compensate for stress in shear, is sufficiently flexible to accomodate extensive misalignment of the sewer pipe, and yet is capable of affording an absolute fluid-tight seal in the rim of the manhole opening. The torroidal rim provides a sealing tension where it contacts the sewer pipe. The gasket moreover is easy to install, comparatively inexpensive to make, and extremely reliable in use.
Claims (4)
1. A cast, resiliently-deformable gasket for supporting a sewer pipe in a manhole opening and sealing the space between the walls of the opening and the surface of the sewer pipe, said gasket comprising:
(a), a generally-pentagonally-shaped, relatively-large mass and substantial thickness main body portion;
(b), a cylindrical flange member which is integral with said said main body portion and which is in the form of a staight leg portion terminating in an "L"-shaped foot;
and (c), a web of substantial thickness but which is nevertheless of less thickness than that of said main body portion, extending radially-inwardly at an acute angle from said main body portion, said web terminating in a rim portion of torroidal form, which is integral with said web and which has an inner diameter less than the outer diameter of said pipe;
said cylindrical flange and at least half the mass of said main body portion being adapted to be secured in situ within said manhole at said manhole opening.
(a), a generally-pentagonally-shaped, relatively-large mass and substantial thickness main body portion;
(b), a cylindrical flange member which is integral with said said main body portion and which is in the form of a staight leg portion terminating in an "L"-shaped foot;
and (c), a web of substantial thickness but which is nevertheless of less thickness than that of said main body portion, extending radially-inwardly at an acute angle from said main body portion, said web terminating in a rim portion of torroidal form, which is integral with said web and which has an inner diameter less than the outer diameter of said pipe;
said cylindrical flange and at least half the mass of said main body portion being adapted to be secured in situ within said manhole at said manhole opening.
2. The cast gasket of claim 1 wherein said acute angle at which said web extends radially-inwardly is 45°.
3. The cast gasket of claim 1 wherein said torroidal rim is of a diameter at least twice the thickness of such web.
4. As a new article of manufacture the combination of:
(I) a manhole having an opening therein; and (II) a cast, resiliently-deformable gasket secured in situ within said manhole opening, said gasket supporting a sewer pipe in said manhole opening and sealing the space between the walls of said opening and the surface of said sewer pipe, said gasket comprising:
(a), a generally-pentagonally-shaped, relatively-large mass and substantial thickness main body portion;
(b), a cylindrical flange member which is integral with said said main body portion and which is in the form of a staight leg portion terminating in an "L"-shaped foot; and (c), a web of substantial thickness but which is nevertheless of less thickness than that of said main body portion, extending radially-inwardly at an acute angle from said main body portion, said web terminating in a rim portion of torroidal form, which is integral with said web and having an inner diameter less than the outer diameter of said pipe;
said cylindrical flange and at least half the mass of said main body portion being secured in situ within said manhole at said manhole opening.
(I) a manhole having an opening therein; and (II) a cast, resiliently-deformable gasket secured in situ within said manhole opening, said gasket supporting a sewer pipe in said manhole opening and sealing the space between the walls of said opening and the surface of said sewer pipe, said gasket comprising:
(a), a generally-pentagonally-shaped, relatively-large mass and substantial thickness main body portion;
(b), a cylindrical flange member which is integral with said said main body portion and which is in the form of a staight leg portion terminating in an "L"-shaped foot; and (c), a web of substantial thickness but which is nevertheless of less thickness than that of said main body portion, extending radially-inwardly at an acute angle from said main body portion, said web terminating in a rim portion of torroidal form, which is integral with said web and having an inner diameter less than the outer diameter of said pipe;
said cylindrical flange and at least half the mass of said main body portion being secured in situ within said manhole at said manhole opening.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 549536 CA1326050C (en) | 1987-10-16 | 1987-10-16 | Cast gasket |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 549536 CA1326050C (en) | 1987-10-16 | 1987-10-16 | Cast gasket |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1326050C true CA1326050C (en) | 1994-01-11 |
Family
ID=4136667
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 549536 Expired - Fee Related CA1326050C (en) | 1987-10-16 | 1987-10-16 | Cast gasket |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1326050C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108730634A (en) * | 2018-04-19 | 2018-11-02 | 中国核电工程有限公司 | A kind of nuclear power heat-shrinkable T bush seal gas device |
-
1987
- 1987-10-16 CA CA 549536 patent/CA1326050C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108730634A (en) * | 2018-04-19 | 2018-11-02 | 中国核电工程有限公司 | A kind of nuclear power heat-shrinkable T bush seal gas device |
| CN108730634B (en) * | 2018-04-19 | 2022-08-19 | 中国核电工程有限公司 | Gas sealing device for nuclear power heat-shrinkable sleeve |
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