GB1601674A - Sliding seal for pistons and piston rods - Google Patents
Sliding seal for pistons and piston rods Download PDFInfo
- Publication number
- GB1601674A GB1601674A GB7566/78A GB756678A GB1601674A GB 1601674 A GB1601674 A GB 1601674A GB 7566/78 A GB7566/78 A GB 7566/78A GB 756678 A GB756678 A GB 756678A GB 1601674 A GB1601674 A GB 1601674A
- Authority
- GB
- United Kingdom
- Prior art keywords
- ring
- pressure
- sealing
- seal
- combination
- 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
Links
- 238000007789 sealing Methods 0.000 claims description 67
- 239000000314 lubricant Substances 0.000 claims description 35
- 230000001050 lubricating effect Effects 0.000 claims description 27
- 239000000463 material Substances 0.000 claims description 26
- 239000004744 fabric Substances 0.000 claims description 17
- 239000007788 liquid Substances 0.000 claims description 6
- 230000015572 biosynthetic process Effects 0.000 claims description 5
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 5
- 239000011707 mineral Substances 0.000 claims description 5
- 239000012530 fluid Substances 0.000 claims description 4
- 238000003780 insertion Methods 0.000 claims description 4
- 230000037431 insertion Effects 0.000 claims description 4
- 239000011159 matrix material Substances 0.000 claims description 4
- 238000003860 storage Methods 0.000 claims description 4
- 238000003825 pressing Methods 0.000 claims description 3
- 230000002787 reinforcement Effects 0.000 claims description 3
- 230000006835 compression Effects 0.000 claims description 2
- 238000007906 compression Methods 0.000 claims description 2
- 239000013013 elastic material Substances 0.000 claims description 2
- 239000007787 solid Substances 0.000 description 8
- 239000010410 layer Substances 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- CWQXQMHSOZUFJS-UHFFFAOYSA-N molybdenum disulfide Chemical compound S=[Mo]=S CWQXQMHSOZUFJS-UHFFFAOYSA-N 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005461 lubrication Methods 0.000 description 2
- 229910052982 molybdenum disulfide Inorganic materials 0.000 description 2
- 229920003051 synthetic elastomer Polymers 0.000 description 2
- 239000005061 synthetic rubber Substances 0.000 description 2
- HLEBDBBUKYGLCB-UHFFFAOYSA-N 1,1,2,3,3,3-hexafluoroprop-1-ene;hydrofluoride Chemical class F.FC(F)=C(F)C(F)(F)F HLEBDBBUKYGLCB-UHFFFAOYSA-N 0.000 description 1
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- 229910000906 Bronze Inorganic materials 0.000 description 1
- 239000013543 active substance Substances 0.000 description 1
- 239000010974 bronze Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- YACLQRRMGMJLJV-UHFFFAOYSA-N chloroprene Chemical compound ClC(=C)C=C YACLQRRMGMJLJV-UHFFFAOYSA-N 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 1
- 125000002573 ethenylidene group Chemical group [*]=C=C([H])[H] 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 230000002045 lasting effect Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229920003052 natural elastomer Polymers 0.000 description 1
- 229920001194 natural rubber Polymers 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000003566 sealing material Substances 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
- F16J15/324—Arrangements for lubrication or cooling of the sealing itself
-
- 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
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/164—Sealings between relatively-moving surfaces the sealing action depending on movements; pressure difference, temperature or presence of leaking fluid
-
- 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
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/166—Sealings between relatively-moving surfaces with means to prevent the extrusion of the packing
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Sealing Devices (AREA)
- Sealing With Elastic Sealing Lips (AREA)
Description
(54) SLIDING SEAL FOR PISTONS AND PISTON RODS
(71) We, TAUNUS ARMATUREN
GmbH, a German company of Taunusstrasse 8, D-6277 Camberg/T, Federal
Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention concerns a sliding seal for pistons and piston rods of working cylinders and for floating pistons of pressure storage units consisting of a combination of sealing and lubricating rings, wherein a high local pressure may be produced to obtain substantially complete dry running of the seal combination and wherein the lubricating is of a plastically deformable material which is not self-lubricating but contains a high proportion of dry-mineral lubricants.
In seal combinations of this kind, the lubricating rings themselves are of a plastically deformable material, which in itself is not self-lubricating, but which serves as a loose supporting framework for a high proportion of a solid lubricant of molybdenum disulfide (MoS2) or similar substances. However, lubricating rings of this kind become fully effective only when sliding friction on practically dry sliding surfaces is obtained, and the lubricating ring itself or the detached, abraded solid lubricant particles are subjected to shear forces sufficiently high as to separate suitable startified lattice lamina of single crystal platelets.
In one known sealing combination of the type mentioned, the high stress required for the solid lubricant and the equally important dry operation are made possible by pressing a high strength, elastic sealing matenal (preferably cross-linked polyurethane having about twice the strength of conventional natural and synthetic rubber seals) very strongly against the sliding surface with the aid of a stepped groove or slot, thus obtaining optimum reductions of the friction coefficient, wear and frictional heat, by reason of the smooth and compact layer of the solid lubricant produced between the seal and the original sliding surface.
In keeping with the state of the art, however, permanent pressure on the highly elastic seals of a sufficient degree can be produced only with materials having a narrowly limited field of application and, these materials specifically cannot be used at elevated working temperatures, when the pressurizing agent contains traces of water, or when using synthetic, barely flammable or organic hydraulic liquids. Apart from this, the need for a stepped sealing groove or slot prevents, in the known art, the use of this seal combination with existing rectangular sealing slots.
In another known sealing combination, the elastic sealing ring is supported against the side of the groove facing away from the pressure with a so-called back-up ring (washer) with additional lips pointing in the direction of the sealing ring. The lips are intended to counteract the destruction and "nibbling" effect of the sealing ring. Backup rings of this type, because of their shape, cannot be cut from simple pieces of tubing and thus their production is relatively expensive. Beyond this, while such backup rings can be combined with sealing rings made of different materials, they themselves cannot be made of materials forming loose, plastic supporting matrices for supporting solid lubricants.Furthermore, such a sealing combination, even with additional lips on the backup rings, does not satisfy any of the conditions (absolute tightness, usually high compressive and shear forces) necessary for the formation of a homogeneous, smooth solid lubricant layer without detectable laminar boundaries on the surface to be sealed.
Another known sealing arrangement contains, between an inner ring and outer, hard backup rings, a relatively soft intermediate ring having good adaptability through plastic flow to the adjacent structural parts.
Because of the parallel shape given and the so-called "cold flow" of the intermediate ring, the extrusion gap caused by high operating pressures and also produced by manufacturing inaccuracies, is completely sealed, thus also protecting the inner ring itself against destruction by "nibbling".
Here again, however, practically absolute tightness cannot be obtained, especially at higher piston velocities and/or with rough sliding surfaces, nor can adequate shearing force be permanently applied on the solid lubricant which may be incorporated in the intermediate ring. The slight proportion of the solid lubricant potentially present, in addition, is solidly bonded to the base material of the intermediate ring. Even with respect to mass, the amount present would not be sufficient to form a compact intermediate layer between the original sliding surface and the gasket. Generally known sealing combinations with compact crosssections of the rings are not always satisfactory in practical applications.This is also true of the so-called sleeve packings, using sealing materials such as fabric-reinforced grades of synthetic rubber, including polymers or copolymers of butadiene, acrylonitrile, chloroprene or vinylidene and hexafluoropropene fluorides.
Beside the fact that these sealing combinations may be used only in highly machined tubular cylinders, fabric reinforcements are used primarily so that the fabric pattern of the sliding part will retain traces of the liquid pressurizing agent in order to provide a so-called "liquid emergency lubrication" under critical operating conditions and thus to prevent a sudden collapse of the seals.
It is of disadvantage in this instance that the amount of oil embedded in the fabric matrix is entirely inadequate for the establishment of a hydrodynamic lubricating film on the rings themselves, and on the guiding surfaces associated with it. In order to obtain a saturation of the fabric matrix with liquid pressurizing agents, the sealing action at the ring edges or at the ring must reduced to the extent that if a higher functional quality of such sealing combinations is required, in most cases several rings must be applied to one sealing location or the location must be greatly extended and designed with a plurality of sealing edges.
Sealing combinations of the type described are expensive and their troublefree use is generally possible only, if first an acceptable compromise between permiss bible leakage and durability is obtained through extensive experimentation under operating conditions that must be defined as closely as possible.
An object of the invention is to provide a seal combination which alleviates or overcomes the abovementioned disadvantages of the known seal combinations.
According to the invention there is provided a sliding seal combination for pistons and piston rods of working cylinders and for floating pistons of pressure storage units comprising a combination of sealing and lubricating rings, enabling a high local pressure to be produced between the seal and the running surface against which it bears thereby to obtain practically complete dryrunning of the seal combination, wherein the lubricating ring is of a plastically deformable material which is not selflubricating but contains a high proportion of dry mineral lubricants and wherein the sealing ring or at least one of a number of support rings directly contacting the sealing ring includes a fabric reinforced part which supports and generates additional pressure at the sealing surface or edge whenever the sealing ring bears on the running surface.
The lubricating ring may be arranged in use so as to be totally enclosed and subjected to additionally radially outwardly acting pressure, urging it against the running surface, as the other parts of the seal combination deform under the operating pressure.
The lubricating ring may be arranged so as to be totally enclosed and in use subjected to additional radially outwardly acting pressure, urging it against the running surface, by the action of a spring arrangement included in the seal combination whereby to eliminate voids.
The lubricating ring is, in one embodiment, in two parts which parts include different dry lubricants, the first lubricant having a high level of bonding power with the material of the surface to be sealed whilst the second dry lubricant is chemically inert with respect to the material of the surface to be sealed.
The dry lubricants of the plastically deformable ring may be of different materials at least one of which has a high level of bonding power with the material of the surface to be sealed whilst at least one other dry lubricant is chemically inert with respect to the material of the surface to be sealed.
Embodiments of the invention provide that a sealing ring made of a material selected without regard to the strength of its basic component (the material is thus chosen solely with regard to its elasticity and suitability for use in effective contact with the chosen pressure medium) bears with additional high radial pre-loading against the surface to be sealed owt presses a corresponding lubricating ring with such pressure against the sliding surface of the tubular cylinder or piston rod so that positive dryrunning is ensured in all the usual pressure ranges even at high stroking speeds and the named pressure is so great that the dry lubricant used can fix itself securely to the original sliding surfaces without any disturbing interference by deterging or dispersing quantities of the working medium and moreover singe-crystal dry lubricant strips detach under shear stress. In spite of the dry friction this causes, the friction is extremely small at all the parts moving in relation to one another because the dry lubricant released by the lubricating ring forms a track on the corresponding sliding surfaces with a surface roughness which is usually of the order of 0.4 to 1.0 um, even if the original roughness of the metal sliding surfaces was 12-20 um before the brief running-in period.This smoothness of the sliding surfaces, which cannot normally be produced by conventional metal-removing machining methods in tubular cylinders for example, in combination with the friction parameters for the coating of pure molybdenum disulphide for example that forms over the original sliding surface with roughly comparable low values for dynamic and static friction, also offers the following advantage: The wellknown tendency of seals to "stick fast" in cylinders which have to be kept motionless under high pressure for fairly long periods and work with pressure fluids with poor lubricating properties is totally eliminated and with it the violent "unsticking" of such cylinders (e.g. pit props) when actuated actively or passively.In addition, the most important requirement for satisfactory lubrication and practically unlimited lubricating ring life - firm and lasting anchorage of the dry lubricant by polarisation forces on the corresponding surface being sealed - is satisfied since the dry lubricant is rubbed over and into the surface being sealed and directionally orientated by the sliding movement.
One particularly important point here is that because of the prevention of the formation of a film of fluid between the surface being sealed and the lubricating ring, the dry lubricant can be anchored by polarisation forces undisturbed since the effects of corresponding active agents which otherwise severely impede this process can no longer play a part in the working medium. Moreover, thanks to the extremely simple design, the production and tooling costs necessarily incurred otherwise with such seal combinations are substantially reduced, and the plastic or bronze guide rings otherwise needed when the cylinder is subject to flexural forces can even be eliminated altogether as the extremely compressionresistant interlayer safely prevents scoring of the guiding parts.
The invention will be explained in more detail with reference to the accompanying drawings in which:
Figures 1 and 2 show axial sections of different versions of single acting seals;
Figures 3 and 4 show diagrammatic axial-section views of two piston seals, one single-acting, the other double-acting;
Figures 5 and 6 shows the same sectional views but of two piston-rod seals.
Figures 7 to 10 shows axial sectional views of various single and double acting seals embodying the invention.
Figs. 1 and 2 show axial cross sections of a single acting piston or piston rod seal 11 with a ring 12, containing a high proportion of a dry lubricant. A guideline line 13 indicates the location of the surface of a not otherwise shown piston rod or tubular cylinder to be sealed when completely assembled. For the sake of clarity, the seal is illustrated in the form it has prior to insertion of the piston rod or the insertion of the associated tube cylinder.Both seals 11 are designed as a single piece and consist of a fully elastic section 1 lea and a fabric reinforced section 1 lib. The section 1 lea extends to form a sealing edge 14 and the fabric reinforced section 1 lb is shaped as shown to suitably reinforce, support and stiffen the fully elastic section 1 lea of the seal 11 so that even though adequate elasticity is available in the operational state, the values of the pressure between the sealing edge 14 and the running surface 13 assume a constant magnitude at least twice as high as that in conventional seals, thereby ensuring the success desired with respect to dry running and the formation of a lubricant layer on the running surface.
In figures 3-6, after complete assembly, a piston 1 slides inside a cylinder barrel (not shown) or a piston rod (not shown) moves in an end closure 2 and the pressure medium concerned exerts a pressure in the direction of the arrows 3 or an alternating pressure in the direction of arrows 3a and 3b on the sliding seal combination 4.
The seal combination 4 is disposed in a conventional seal groove 5 and here, by way of example, consists of the actual sealing ring 4a, a fabric-reinforcement 4b on the low pressure side and a ring 4c which is located in a corresponding recess and is made of plastically deformable material which is not self-lubricating but contains a high proportion of dry mineral lubricant.
To obtain complete enclosure of the ring 4c at very high operating pressures, addi totally a supporting nng 6 made of a wearresistant material, and a supporting collar 7, may be arranged at the back of the seal if necessary.
The way in which the desired conversion is achieved within the seal combination is described, for the sake of simplicity, only with reference to Fig. 3, but is achieved in the same manner in the seals of Figs. 4, 5 and 6. The forces acting on the seal combination 4 in service are determined by the prevailing service pressure, the dimensions of the surface area on which the service pressure is acting a (D21 - D22), the prestressing at the sealing edge 4d and the magnitude of frictional forces at the seal during operation, whereas the seal is supported merely over a surface area of zF (D2,- d2X) and the surface area 4 (D23- D2i) of the seal is unsupported or possibly supported only by the return pressure of the low pressure side.The annular space 8 (which has an area 4 (D23 - DZ2) directed toward the high pressure side) cannot be pressurized by the prevailing operation pressure, or by the seal itself under the operating pressure, as any pressurized fluid in the annular space 8 can escape therefrom via the normally slotted supporting ring 6, or across the relatively rough end face of ring 4c on the low pressure side, and through the interstices of the matrix of the fabric reinforcement 4b.
This combination of forces acting in use on the seal combination presses the ring 4c more strongly than in conventional seal combinations against its corresponding metallic sliding surface (not shown) which produces an extremely smooth, pressureresistant lubricant layer on the metallic sliding surface.
Fig. 7 shows a seal combination 11 for the sealing of the running surface of a piston rod (not shown). Between the fabric reinforced sealing parts, namely the pressure ring 16, the sealing and support ring 13' and the sealing and support ring 14'; there is a sealing ring 15' of entirely elastic material. A ring 12 of a plastically deformable, non-selflubricating material and containing a high proportion of a dry lubricant, is located between the surface of the supporting ring 14', facing away from the pressure and the flank 17 of the sealing groove, again facing away from the pressure.
The entire seal combination 11 is arranged longitudinally such that, after assembly in the sealing groove strong pressure in the axial direction is ensured by the groove flanks 17 and 18 via the shoulder 19 of the pressure ring 16 (which may include pressure equalizing notches) which after the insertion of the piston rod (not shown) results firstly in complete enclosure of the individual sealing parts and, secondly pressing the sealing parts against the surface of the piston rod at such a high pressure not allowable with known sealing combinations.
The magnitude of this further additional pressure is determined in a simple manner by axial deformation of the various parts of the combination, forced by the action of shoulder 19 in the space between the flanks 17 and 18 of the sealing groove, so that the ring 12 immediately produces a smooth, pressure resistant lubricating layer on the running surface of the moving piston rod, while simultaneously the fully elastic gasket 15' assures dry running at all stroke velocities. A corresponding axial deformation may be produced by means other than the shoulder 19, e.g. by a compression or diaphragm spring acting axially, useful in eliminating voids.
In Figs. 8, 9 and 10, the same designations as in Figs. 1 and 2 are used. So-called "compact seals" are illustrated with the conventional low pressure at the sealing edge 14 and the sealing part 15. The high pressure required for the safe operating of the ring 12 on the running surface represented by the guideline 13 is produced by the ring 12, embedded in the rigid fabric section 1 lib, by the fact that the radial height of the ring 12 is greater than the corresponding height of the recess provided for the embedding in section 1 lib. For this reason, the ring 12 is pressured radially and directly between the corresponding running surface and the bottom of the embedding groove. The mag- nitude of this radial pressure can be determined specifically by the rigidity of the fabric section.
It will be appreciated that the described embodiments provide seal combinations which safely prevent the formation of a film of a liquid originating in the operating medium, both in the high pressure range and under very slight pressures of the working medium and at very different stroke velocities on the side of the sealing combination or the oil ring facing away from the pressure. This is accomplished without suffering appreciable piston and piston rod wear in operation and additionally, permitting the use of extraordinarily rough sliding surfaces in the tubular cylinders or piston rods.
WHAT WE CLAIM IS:
1. A sliding seal combination for pistons and piston rods of working cylinders and for floating pistons of pressure storage units, comprising a combination of sealing and lubricating rings, enabling a high local pressure to be produced between the seal and the running surface against which it bears thereby to obtain practically complete dryrunning of the seal combination, wherein the lubricating ring is of a plastically deformable material which is not selflubricating but contains a high proportion of dry mineral lubricants and wherein the sealing ring or at least one of a number of support rings directly contacting the sealing ring includes a fabric reinforced part which supports and generates additional pressure at the sealing surface or edge whenever the sealing ring bears on the running surface.
2. A seal combination according to claim 1, wherein the lubricating ring is arranged in use so as to be totally enclosed and is in use subject to further additional radially outwardly acting pressure, urging it against the running surface, as the other parts of the seal combination deform under the operating pressure.
3. A seal combination according to claim 1, wherein the lubricating ring is arranged so as to be totally enclosed and is
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (6)
1. A sliding seal combination for pistons and piston rods of working cylinders and for floating pistons of pressure storage units, comprising a combination of sealing and lubricating rings, enabling a high local pressure to be produced between the seal and the running surface against which it bears thereby to obtain practically complete dryrunning of the seal combination, wherein the lubricating ring is of a plastically deformable material which is not selflubricating but contains a high proportion of dry mineral lubricants and wherein the sealing ring or at least one of a number of support rings directly contacting the sealing ring includes a fabric reinforced part which supports and generates additional pressure at the sealing surface or edge whenever the sealing ring bears on the running surface.
2. A seal combination according to claim 1, wherein the lubricating ring is arranged in use so as to be totally enclosed and is in use subject to further additional radially outwardly acting pressure, urging it against the running surface, as the other parts of the seal combination deform under the operating pressure.
3. A seal combination according to claim 1, wherein the lubricating ring is arranged so as to be totally enclosed and is
in use subjected to further additional radially outwardly acting pressure, urging it against the running surface, by the action of a spring arrangement included in the seal combination whereby to eliminate voids.
4. A seal combination according to any one of claims 1 to 3, wherein the lubricating ring is in two parts which parts include different dry lubricants, the first lubricant having a high level of bonding power with the material of the surface to be sealed whilst the second dry lubricant is chemically inert with respect to the material of the surface to be sealed.
5. A seal combination according to any one of claims 1 to 3, wherein the dry lubricants of the plastically deformable ring are of ditterent materials at least one of which has a high level of bounding power with the material of the surface to be sealed whilst at least one other dry lubricant is chemically inert with respect to the material of the surface to be sealed.
6. A sliding seal combination for pistons and piston rods of working cylinders, substantially as herein described with reference to the accomDanvin drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2708456A DE2708456B2 (en) | 1977-02-26 | 1977-02-26 | Sliding seal for pistons and piston rods |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1601674A true GB1601674A (en) | 1981-11-04 |
Family
ID=6002275
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7566/78A Expired GB1601674A (en) | 1977-02-26 | 1978-02-24 | Sliding seal for pistons and piston rods |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS53112360A (en) |
| CA (1) | CA1136173A (en) |
| DE (1) | DE2708456B2 (en) |
| FR (1) | FR2381949A1 (en) |
| GB (1) | GB1601674A (en) |
| SE (1) | SE7802215L (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2573337A1 (en) * | 2011-09-23 | 2013-03-27 | Arno Hofmann | Assembly of a gate valve and a seal system for sealing the gate valve of a thermal engine |
| WO2019195698A1 (en) * | 2018-04-05 | 2019-10-10 | Caterpillar Global Mining Llc | Hydraulic cylinder service life improvement |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5863189U (en) * | 1981-10-24 | 1983-04-27 | 極東マツク・グレゴ−株式会社 | Watertight device for hatch lid |
| US4576386A (en) * | 1985-01-16 | 1986-03-18 | W. S. Shamban & Company | Anti-extrusion back-up ring assembly |
| JP2535098Y2 (en) * | 1991-08-26 | 1997-05-07 | 三菱電線工業株式会社 | Sealing device |
| DE4230123A1 (en) * | 1992-09-09 | 1994-03-17 | Fichtel & Sachs Ag | Cylinders for hydraulic and / or pneumatic systems |
| US7726339B2 (en) * | 2006-01-14 | 2010-06-01 | Dresser, Inc. | Seal cartridge control valve |
| US9073527B2 (en) * | 2011-03-31 | 2015-07-07 | Haldex Brake Corporation | Smooth bore dynamic center seal for spring brake actuator |
| FR2975148A1 (en) * | 2011-05-13 | 2012-11-16 | Peugeot Citroen Automobiles Sa | Device for protecting shaft of car, has sleeve including bore with inlet portion having camelback shaped longitudinal section, where vertices of section are dimensioned to compress seal during removal of shaft from sleeve to lubricate shaft |
| DE102014106488B4 (en) | 2014-05-08 | 2024-01-04 | Knorr-Bremse Systeme für Nutzfahrzeuge GmbH | Recirculating ball steering with sliding element |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2797971A (en) * | 1955-11-14 | 1957-07-02 | Cleveland Pneumatic Tool Co | Sectional fluid seal |
-
1977
- 1977-02-26 DE DE2708456A patent/DE2708456B2/en not_active Withdrawn
-
1978
- 1978-02-21 CA CA000297392A patent/CA1136173A/en not_active Expired
- 1978-02-24 FR FR7805332A patent/FR2381949A1/en active Pending
- 1978-02-24 GB GB7566/78A patent/GB1601674A/en not_active Expired
- 1978-02-27 SE SE7802215A patent/SE7802215L/en unknown
- 1978-02-27 JP JP2103278A patent/JPS53112360A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2573337A1 (en) * | 2011-09-23 | 2013-03-27 | Arno Hofmann | Assembly of a gate valve and a seal system for sealing the gate valve of a thermal engine |
| WO2013041233A1 (en) * | 2011-09-23 | 2013-03-28 | Arno Hofmann | Arrangement of a slide valve and a seal system for sealing the slide valve in a heat engine |
| WO2019195698A1 (en) * | 2018-04-05 | 2019-10-10 | Caterpillar Global Mining Llc | Hydraulic cylinder service life improvement |
| US11041511B2 (en) | 2018-04-05 | 2021-06-22 | Caterpillar Global Mining Llc | Hydraulic cylinder service life improvement |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS53112360A (en) | 1978-09-30 |
| DE2708456A1 (en) | 1978-08-31 |
| SE7802215L (en) | 1978-08-27 |
| CA1136173A (en) | 1982-11-23 |
| FR2381949A1 (en) | 1978-09-22 |
| DE2708456B2 (en) | 1980-10-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| 732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |