GB1572462A – Piston or like sealing or packing
– Google Patents
GB1572462A – Piston or like sealing or packing
– Google Patents
Piston or like sealing or packing
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Publication number
GB1572462A
GB1572462A
GB1559976A
GB1559976A
GB1572462A
GB 1572462 A
GB1572462 A
GB 1572462A
GB 1559976 A
GB1559976 A
GB 1559976A
GB 1559976 A
GB1559976 A
GB 1559976A
GB 1572462 A
GB1572462 A
GB 1572462A
Authority
GB
United Kingdom
Prior art keywords
ring
sealing ring
sealing
circumferential
fluid
Prior art date
1977-04-14
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
Application number
GB1559976A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
George Angus and Co Ltd
Original Assignee
George Angus and Co Ltd
Priority date (The priority date 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 date listed.)
1977-04-14
Filing date
1977-04-14
Publication date
1980-07-30
1977-04-14
Application filed by George Angus and Co Ltd
filed
Critical
George Angus and Co Ltd
1977-04-14
Priority to GB1559976A
priority
Critical
patent/GB1572462A/en
1980-07-30
Publication of GB1572462A
publication
Critical
patent/GB1572462A/en
Status
Expired
legal-status
Critical
Current
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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
F16J15/166—Sealings between relatively-moving surfaces with means to prevent the extrusion of the packing
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
F16J15/46—Sealings with packing ring expanded or pressed into place by fluid pressure, e.g. inflatable packings
F16J15/48—Sealings with packing ring expanded or pressed into place by fluid pressure, e.g. inflatable packings influenced by the pressure within the member to be sealed
Description
(54) IMPROVEMENTS IN AND RELATING TO PISTON OR LIKE
SEALING OR PACKING
(71) We, GEORGE ANGUS & COM
PANY LIMITED, of 148-158 Westgate
Road, Newcastle Upon Tyne, NE99 ITG,
England, a British Company, 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:
This invention relates to sealing rings for use as fluid packings in circumferential grooves in one or other of coaxially-opposed cylindrical surfaces to be sealed, such as piston and cylinder or reciprocating rod packings, for pneumatic or hydraulic sealing purposes, and will be described in relation to a sealing ring in a piston groove.
The invention is a modification of a main invention described and claimed in the specification of our Patent No. 1 475 312.
Claim 1 of the patent claims a fluid packing comprising a sealing ring, moulded from elastomeric material, housed in a circumferential groove in one of two opposed, coaxially-cylindrical, surfaces to be sealed, the selaing ring having an apex portion, with a radially-directed circumferential sealing band in contact with the other, ungrooved, cylindrical surface, and a pair of circumferential flanges which diverge from the apex portion and respectively have a lateral, axiallydirected, sealing band to contact a respective opposed wall of the groove, in which the peripheral edges of the flanges do not seal against the base of the groove so that, when the sealing ring is under fluid pressure from one side, the flange facing the pressure can yield to admit fluid past its lateral sealing contact band and into the cavity between the flanges of the ring.
Claim 2 of the Patent claims a sealing ring according to claim 1 in which each flange has,
at its peripheral edge, passages for axial transfer of fluid beyond the respective lateral sealing band.
According to the present invention there is
provided a fluid packing comprising a sealing
ring as claimed in Claim 1 or Claim 2 of
Patent No. 1 475 312, wherein the sealing
ring is of arched U-shape in radial axial sec
tion of which section the over-all axial
dimension is more than twice the over-all
radial dimension and a pair of anti-extrusion rings is provided in the groove to bracket the
radially-directed circumferential sealing surface of the sealing ring.
Preferably the anti-extrusion rings are
each of substantially right-angled triangular section with a hypotenuse face, oblique to the axis of the ring, mating with a fitting face on the sealing ring. The face on the sealing ring may be a frusto-conical facet or substantially the whole of a frusto-conical end face of the sealing ring.
The sealing ring may have only one of the circumferential end flanges provided with means, preferably passages in the peripheral edge of the flange, for admission of fluid into the cavity between the flanges so as to provide a single-acting packing effective in only one axial direction.
Preferably also, the radially-directed circumferential sealing band has, in its undeformed condition, a slight circumferential concavity between well-defined circumferential edges so that, on initial assembly, good circumferential sealing contact is established and fluid under pressure will preferentially pass a respective flange into the cavity between the flanges. With fluid under pressure in the cavity, the radially-directed circumferential sealing band is thrust into full surface contact with the opposed cylindrical surface, the slight concavity being filled by deformation of the elastomeric material of the sealing ring.
It will be apparent that the invention is applicable to sealing rings each with an outwardly or an inwardly radially-directed circumferential sealing band, the ring being respectively housed in a piston groove or a cylinder groove for example.
Further features of the invention are included in the following description of piston packings illustrated, by way of example, on the accompanying drawings, in which:
Figure 1 is a fragmentary axial section, showing the radial axial section, through an elastomeric sealing ring, and a pair of antiextrusion rings shown spaced therefrom, in accordance with the invention,
Figure 2 is a corresponding fragmentary axial section showing the elastomeric sealing ring and anti-extrusion rings of Figure 1 fitted in a piston groove,
Figure 3 is a broken fragmentary axial section of a modified form of the elastomeric ring of Figures 1 and 2, and,
Figure 4 is a view, similar to Figure 1, showing an alternative form of sealing ruing.
As shown by Figure 1, an elastomeric sealing ring 1, of natural or synthetic rubber for example, is moulded to an arched U-shape in radial axial section so that it has obliquelyinclined circumferential end flanges 2 and 3 which are radially inwardly directed to fit between the end walls 5 and 6 of a groove 7 in the wall of a piston 8 in a cylinder 9 (Figure 2).
As shown by Figure 2, in use the ring 1 is axially compressed to fit resiliently, with its end flanges bowed inwardly, in the piston groove and the outer periphery 4 of the sealing ring forms an outwardly radiallydirected, circumferential sealing band against the cylinder wall.
The axial dimension of the radial axial section of the elastomeric ring 1 is substantially longer than its radial dimension, being more than twice as long, so that its outer periphery provides a relatively extensive seal against the bore surface of the cylinder 9.
To prevent extrusion of the material of the elastomeric ring 1 under fluid pressure, into the small gap between the piston 8 and cylinder 9, a pair of anti-extrusion rings 10 and 11 are provided.
The rings 10 and 11 are of a hard, flexible but not easily deformable material, for example a plastics material such as acetal, and are made of substantially right angled triangular section, rounded at the apex, with an inwardly-directed hypotenuse face 12, oblique to the axis of the ring, to mate with a fitting frusto-conical face 13 moulded as a facet on the respective end of the elastomeric ring 1.
The end flanges of the ring 1 of Figures 1 and 2 are each moulded with a circumferential edge 14 to ensure presentation of an axially directed lateral sealing band against the respective end wall of the piston groove.
The ring 1 thus seals in the piston groove as well as against the cylinder bore surface.
When the sealing ring 1 comes under fluid pressure from one axial direction or the other, it is desirable to balance the fluid pressure within the cavity 15 of the ring and this can be done by admitting pressure fluid past the respective pressure-side flange 2 or 3. To provide for this, each flange has an axial groove or grooves 16 in its inner periphery beyond the lateral sealing edge 14 so that the flange cannot seal against the base of the piston groove and fluid passing the edge 14 is admitted to the cavity 15. The fluid pressure in the cavity is thus balanced with the axial fluid pressure on the sealing ring and effective to supplement the elastomeric sealing pressure of the ring at its outer periphery and down-stream flange.
The sealing ring of Figures 1 and 2 is a double-acting ring, effective for either axial direction of applied fluid pressure, but for some purposes there is a requirement for a single-acting sealing ring to operate under fluid pressure in one axial direction only.
A single-acting ring is shown by Figure 3 in which only one flange 17 has a groove or grooves 18, or a hole 19, to face the fluid pressure side of the packing and ensure admittance of pressure fluid to the cavity 15.
The other elastomeric ring flange 20 is of full section with a circumferential edge 14 to ensure sealing in the piston groove.
In the alternative form of sealing ring shown by Figure 4, a definite bead 22 is moulded as the lateral sealing band on each end flange of the sealing ring, fluid-transfer passages 23 are moulded at angular intervals in the peripheral edge of each flange, within the compass of the beads 22, and the ends of sealing ring have single frusto-conical faces 24 to mate, by their outer portions only, with the hypotenuse faces 12 of the antiextrusion rings.
In Figures 1, 3 and 4, the outward, radially-directed sealing band of the sealing ring is shown, in the undeformed condition of the ring, with a slight circumferential concavity formed by a shallow channel with a cylindrical bed 25 and sides 26 sloping to meet well-defined circumferential edges 27. This formation ensures that, on initial assembly, the edges 27 establish good sealing contact with the cylinder wall and, when the packing comes under pressure, preferential passage of fluid past the respective end flange of the sealing ring into the cavity between the flanges. Under pressure of fluid in the cavity, the circumferential sealing band makes full contact with the cylinder wall, as indicated in
Figure 2, the slight concavity in the sealing band being filled by distention of the rubber of the sealing ring.
WHAT WE CLAIM IS:
1. A fluid packing comprising a sealing ring as claimed in Claim 1 or Claim 2 of
Patent No. 1 475 312, wherein the sealing ring is of arched U-shape in radial axial section of which section the over-all radial dimension is more than twice the over-all
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (6)
**WARNING** start of CLMS field may overlap end of DESC **. Further features of the invention are included in the following description of piston packings illustrated, by way of example, on the accompanying drawings, in which: Figure 1 is a fragmentary axial section, showing the radial axial section, through an elastomeric sealing ring, and a pair of antiextrusion rings shown spaced therefrom, in accordance with the invention, Figure 2 is a corresponding fragmentary axial section showing the elastomeric sealing ring and anti-extrusion rings of Figure 1 fitted in a piston groove, Figure 3 is a broken fragmentary axial section of a modified form of the elastomeric ring of Figures 1 and 2, and, Figure 4 is a view, similar to Figure 1, showing an alternative form of sealing ruing. As shown by Figure 1, an elastomeric sealing ring 1, of natural or synthetic rubber for example, is moulded to an arched U-shape in radial axial section so that it has obliquelyinclined circumferential end flanges 2 and 3 which are radially inwardly directed to fit between the end walls 5 and 6 of a groove 7 in the wall of a piston 8 in a cylinder 9 (Figure 2). As shown by Figure 2, in use the ring 1 is axially compressed to fit resiliently, with its end flanges bowed inwardly, in the piston groove and the outer periphery 4 of the sealing ring forms an outwardly radiallydirected, circumferential sealing band against the cylinder wall. The axial dimension of the radial axial section of the elastomeric ring 1 is substantially longer than its radial dimension, being more than twice as long, so that its outer periphery provides a relatively extensive seal against the bore surface of the cylinder 9. To prevent extrusion of the material of the elastomeric ring 1 under fluid pressure, into the small gap between the piston 8 and cylinder 9, a pair of anti-extrusion rings 10 and 11 are provided. The rings 10 and 11 are of a hard, flexible but not easily deformable material, for example a plastics material such as acetal, and are made of substantially right angled triangular section, rounded at the apex, with an inwardly-directed hypotenuse face 12, oblique to the axis of the ring, to mate with a fitting frusto-conical face 13 moulded as a facet on the respective end of the elastomeric ring 1. The end flanges of the ring 1 of Figures 1 and 2 are each moulded with a circumferential edge 14 to ensure presentation of an axially directed lateral sealing band against the respective end wall of the piston groove. The ring 1 thus seals in the piston groove as well as against the cylinder bore surface. When the sealing ring 1 comes under fluid pressure from one axial direction or the other, it is desirable to balance the fluid pressure within the cavity 15 of the ring and this can be done by admitting pressure fluid past the respective pressure-side flange 2 or 3. To provide for this, each flange has an axial groove or grooves 16 in its inner periphery beyond the lateral sealing edge 14 so that the flange cannot seal against the base of the piston groove and fluid passing the edge 14 is admitted to the cavity 15. The fluid pressure in the cavity is thus balanced with the axial fluid pressure on the sealing ring and effective to supplement the elastomeric sealing pressure of the ring at its outer periphery and down-stream flange. The sealing ring of Figures 1 and 2 is a double-acting ring, effective for either axial direction of applied fluid pressure, but for some purposes there is a requirement for a single-acting sealing ring to operate under fluid pressure in one axial direction only. A single-acting ring is shown by Figure 3 in which only one flange 17 has a groove or grooves 18, or a hole 19, to face the fluid pressure side of the packing and ensure admittance of pressure fluid to the cavity 15. The other elastomeric ring flange 20 is of full section with a circumferential edge 14 to ensure sealing in the piston groove. In the alternative form of sealing ring shown by Figure 4, a definite bead 22 is moulded as the lateral sealing band on each end flange of the sealing ring, fluid-transfer passages 23 are moulded at angular intervals in the peripheral edge of each flange, within the compass of the beads 22, and the ends of sealing ring have single frusto-conical faces 24 to mate, by their outer portions only, with the hypotenuse faces 12 of the antiextrusion rings. In Figures 1, 3 and 4, the outward, radially-directed sealing band of the sealing ring is shown, in the undeformed condition of the ring, with a slight circumferential concavity formed by a shallow channel with a cylindrical bed 25 and sides 26 sloping to meet well-defined circumferential edges 27. This formation ensures that, on initial assembly, the edges 27 establish good sealing contact with the cylinder wall and, when the packing comes under pressure, preferential passage of fluid past the respective end flange of the sealing ring into the cavity between the flanges. Under pressure of fluid in the cavity, the circumferential sealing band makes full contact with the cylinder wall, as indicated in Figure 2, the slight concavity in the sealing band being filled by distention of the rubber of the sealing ring. WHAT WE CLAIM IS:
1. A fluid packing comprising a sealing ring as claimed in Claim 1 or Claim 2 of
Patent No. 1 475 312, wherein the sealing ring is of arched U-shape in radial axial section of which section the over-all radial dimension is more than twice the over-all
radial dimension and a pair of anti-extrusion rings is provided in the groove to bracket the radially-directed circumferential sealing surface of the sealing ring.
2. A sealing ring according to claim 1 above, in which the anti-extrusion rings are of substantially right-angled triangular section with a hypotenuse face, oblique to the axis of the ring, mating with a fitting face on the sealing ring.
3. A sealing ring according to claim 1 or 2 above, in which only one of the circumferential end flanges of the sealing ring has means providing for admission of fluid into the cavity between the flanges so as to provide a single-acting packing effective in only one axial direction.
4. A sealing ring according to any of claims 1 to 3 above, in which the radiallydirected, circumferential sealing band has, in its undeformed condition, a slight circumferential concavity between well-defined circumferential edges so that, on initial assembly, the edges establish good circumferential sealing contact with the opposed cylindrical surface and consequently fluid under pressure will preferentially pass a respective flange into the cavity between the flanges.
5. A sealing ring according to claim 4 above, in which the concavity has the form of a circumferential shallow channel with a cylindrical bed and sides sloping to meet the circumferential edges.
6. A sealing ring substantially as described with reference to Figures 1 and 2,
Figure 3 or Figure 4 of the accompanying drawings.
GB1559976A
1977-04-14
1977-04-14
Piston or like sealing or packing
Expired
GB1572462A
(en)
Priority Applications (1)
Application Number
Priority Date
Filing Date
Title
GB1559976A
GB1572462A
(en)
1977-04-14
1977-04-14
Piston or like sealing or packing
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
GB1559976A
GB1572462A
(en)
1977-04-14
1977-04-14
Piston or like sealing or packing
Publications (1)
Publication Number
Publication Date
GB1572462A
true
GB1572462A
(en)
1980-07-30
Family
ID=10062028
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB1559976A
Expired
GB1572462A
(en)
1977-04-14
1977-04-14
Piston or like sealing or packing
Country Status (1)
Country
Link
GB
(1)
GB1572462A
(en)
1977
1977-04-14
GB
GB1559976A
patent/GB1572462A/en
not_active
Expired
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Legal Events
Date
Code
Title
Description
1980-10-15
PS
Patent sealed
1987-05-13
PCNP
Patent ceased through non-payment of renewal fee
