Fluid seals

Details Fluid seals Fluid seals

2000-10-05

2003-04-15

Knight, Anthony (Department: 3626)

Seal for a joint or juncture

Seal between fixed parts or static contact against...

Contact seal for a pipe, conduit, or cable

C277S626000, C277S650000, C277S918000, C210S455000, C210S445000

Reexamination Certificate

active

06547255

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention concerns improvements in or relating to fluid seals. The invention has particular, but not exclusive application to fluid seals for sealing joints between two components connected together in a fluid line, for example between two pipes, or between a pipe and another fitting or between two fittings such as a hydraulic block to which one or more parts may be attached, for example a pump or valve application.
It is already well known in the water and automotive industries to provide sealing rings for sealing joints between two components in a fluid line. The sealing rings may be made of rubber or plastics compatible with the fluid to be transmitted in the fluid line, for example water, oil, petrol, solvents.
For many applications, it is desirable to remove any solid particles present in the fluid to prevent damage to equipment connected to the fluid line. For this purpose, it is common to fit a filter in the fluid line, for example a metal or plastics mesh screen having a mesh rating to remove solid particles above a given size.
For convenience, the mesh screen may be fitted at a joint between two components in the fluid line. This can complicate the provision of an adequate seal. In addition, fitting separate seal and filter elements adds to material costs and installation costs. Also, there is a risk of joints being assembled without the filter resulting in damage to equipment connected in the fluid line.
SUMMARY OF THE INVENTION
Accordingly, the present invention seeks to provide an arrangement whereby the seal and filter are combined in a single component for installation in a fluid line.
It is a preferred object of the present invention to provide an arrangement in which a peripheral edge region of the filter is embedded in the seal, and the seal is compressible on either side of the filter between opposed surfaces of relatively axially movable components to effect a fluid tight seal between the components.
It is another preferred object of the present invention to provide an arrangement in which compression of the seal is controlled so as to maintain integrity of the seal and filter.
It is a further preferred object of the present invention to provide an assembly including an adaptor so constructed that fitment and installation of the seal and filter in a fluid line can be effected in a simple and effective manner which preferably also allows access to the filter for cleaning, repair or replacement during routine maintenance and/or in an emergency.
It is yet another preferred object of the present invention to provide such assembly in which the seal and filter are located with the filter in a desired orientation, preferably transverse, to the fluid line in which the adaptor is installed.
According to a first aspect, the present invention provides a solution to the problems and disadvantages aforementioned by providing an integral seal and filter assembly capable of sealing a joint between two components in a fluid line and filtering fluid in the fluid line. In this way, by combining the seal and filter in a single unitary construction the supply and installation of separate seal and filter elements is avoided.
The combined seal and filter can be of any size and shape to suit a given application, for example circular, oval, rectangular, or other polygonal shape. As will be appreciated, by providing an integral seal and filter, the filter can be made to any shape and the seal configured to this shape by attaching to the filter. In this way, both simple and complex seal shapes can be produced and maintained for any desired application.
Preferably, the seal is bonded to the peripheral edge of the filter. For example, the filter may comprise a mesh screen with the peripheral edge embedded in the seal. In this way, the material of the seal penetrates the interstices of the mesh so as to become mechanically bonded through the mesh.
The mesh screen may be made of metal, for example stainless steel, aluminium or brass. Alternatively, the mesh screen may be made of plastics. The mesh can be of any size for the filter rating required for a particular application.
The seal may be made of elastomer, for example rubber such as nitrite rubber, hydrogenated nitrite rubber, ethylene propylene diene monomer, fluorocarbons, polyacrylic, neoprene, fluorosilicon, or other suitable compounds for the intended application. Alternatively, the seal may be made of plastics. The seal material is chosen to be compatible with the fluid in the fluid line.
Advantageously, the mesh is provided with a barrier spaced from the peripheral edge to restrict flow of the seal material from the peripheral edge region towards the centre region of the mesh. In this way, only the peripheral edge region is embedded in the seal material and the centre region is left free to provide the filtering function.
The mesh may be woven and the barrier formed by crushing a narrow region of the mesh inwardly of the peripheral edge prior to or during moulding of the seal to form a crease separating the edge region of the mesh from the centre region to prevent the seal material penetrating the centre region of the filter. This is found to be particularly suitable for woven meshes having a mesh size of up to 200 microns.
Alternatively, the mesh may be produced by photochemical machining an array of perforations in a pre-form and the barrier formed by masking the pre-form to produce a region free from perforations separating the edge region of the mesh from the centre region to prevent the seal material penetrating the centre region of the filter. This is found to be particularly suitable for photofabrication of meshes having a mesh size of more than 200 microns, especially 300 to 400 microns.
Preferably, the seal is formed with a plurality of outwardly projecting lobes spaced apart around the outer edge of the seal and substantially co-planar with the seal and filter. The lobes facilitate moulding the seal onto the filter by allowing the seal material to pass from one side to the other around the outer edge of the filter within the mould. The lobes also act as spacers to centre the seal and filter assembly for installation in a fluid line, for example in a counterbore of a component forming part of the fluid line.
Advantageously, the seal has a sealing portion of generally trapezoidal cross-section with a maximum axial dimension at the inner edge of the seal and sealing surfaces that extend from the inner edge and converge towards each other. In this way, the inner edge of the seal has a substantially planar sectional shape in the undeformed condition of the seal and a substantially concave sectional shape when compressed. As a result, compression of the seal can be accommodated without adversely affecting the integrity of the seal and filter.
The filter provides a degree of reinforcement for the seal which is generally sufficient for most applications of the seal and filter assembly involving low fluid pressures but, at high fluid pressures, for example up to 200 bar, the seal and filter assembly is preferably provided with additional reinforcement. Such reinforcement conveniently takes the form of an outer support member, for example a plate, to which the seal is bonded to form a unitary construction.
Advantageously, the plate has a hole with a counterbore providing a shoulder for locating the peripheral edge of the filter with the seal encapsulating the peripheral edge and bonded to the marginal edge of the hole.
Preferably, the seal projects outwardly from the plate on both sides for sealing engagement with the components of the joint to be sealed. The plate may act as a spacer to limit the compression of the seal. The plate may be made of metal, for example zinc plated steel or stainless steel. Alternatively, the plate may be made of plastics, for example polycarbonate.
According to a second aspect, the present invention provides a method of forming a seal and filter assembly comprising providing a filter and bonding a seal to the marginal edge of the filter.
Preferably, the seal is co

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