GB2606992A

GB2606992A - A method and apparatus for deploying a stent into a conduit

Info

Publication number: GB2606992A
Application number: GB2104665.1A
Authority: GB
Inventors: Buckley Simon
Original assignee: AIR BAG STOPPER HOLDINGS Ltd
Current assignee: AIR BAG STOPPER HOLDINGS Ltd
Priority date: 2021-03-31
Filing date: 2021-03-31
Publication date: 2022-11-30
Anticipated expiration: 2041-03-31
Also published as: GB202104665D0; GB2606992B

Abstract

A stent 1 comprises at least one chamber 2 containing a packing medium and the stent being configurable between a first configuration in which the packing medium in the chamber has a first packing density; and a second configuration in which the packing medium in the chamber has a second packing density, the second packing density being greater than the first packing density. The method comprises the steps of: arranging the stent in the first configuration, when relative flexibility is required; and applying a negative pressure differential to one or more of the at least one chamber containing the packing medium to reconfigure the stent into the second configuration, when relative rigidity is required. The negative pressure may be applied by: a positive force and/or pressure (i.e. compression) or ambient pressure of the conduit; by a vacuum pump or suction or evacuation of fluid (but not the packing medium) from the stent and / or at least one chamber of the stent. Aspects include: the conduit being a pipe (gas, water, sewage) or a corporeal conduit or tubular element (e.g. a vein, artery, blood vessel, aorta, intestine etc); the stent comprising at least one lumen (fluid chamber 4).

Description

A method and apparatus for deploying a stent into a conduit

FIELD OF THE INVENTION

The invention relates to a method and apparatus for deploying a stent into a conduit. A new stent is also disclosed. Aspects of the invention can be used in the repair and maintenance of pipes such as water or gas supply pipes. Moreover, aspects of the invention may find use in medical applications, for example to allow continued fluid flow in a damaged lumen of the body, such as an artery or the oesophagus.

BACKGROUND

Inflatable devices such as inflatable bags/stents are commonly used in plumbing applications, for example for stopping fluid flow in pipes such as gas or water pipes to allow repair and maintenance procedures to be performed.

Stents are typically annular in shape and comprise a central passage to allow fluid to pass through, whilst simultaneously supporting or even isolating a section of pipe that may be damaged or weakened. The stent can bridge across a damaged length of a pipe; from an undamaged section, past the damaged location, to an undamaged section on the other side; to provide a safe passage for fluid flow.

Stents can allow the flow of a fluid within a pipe to be stemmed, restricted or even stopped entirely. Stents may also allow for the insertion of a bypass pipe, diverting or removing the flow of fluid from a specific area, allowing inspection or repair of said area. For example, two such stents can allow isolation of a short section of damaged pipe, by positioning a stent either side of an area to be inspected/repaired and inserting a bypass pipe to connect an upstream and a downstream region of the pipe. A working area may then be isolated or depressurised as necessary without the need to depressurise, isolate or even drain the entire pipe or a long section of pipe to allow safe access for repair or replacement.

Inflatable stents offer the advantage that their inherent compliance allows them to conform to the surface profiles of the working area, ensuring that a sufficient seal is produced and maintained when the stent is adequately inflated.

Operating conditions of stents may typically be severe, for example, high temperature, pressure and flow. Thus, the integrity of a stent is paramount for the insertion, maintained position and ultimate success of the stent.

It is an aim of the present invention to provide a method and apparatus for deploying a stent into a conduit, and a new stent, which helps to ameliorate some or all of the afore-mentioned problems and/or provides a useful alternative approach.

SUMMARY

High pressure environments can be experienced, for example, in gas and water pipes such that large forces may be exerted on a stent that can impact on the ability of the stent to remain fully operational in the working position within such pipes. There is therefore a risk that a stent may be damaged, moved, displaced or ejected from the working position due to such forces.

Furthermore, an inflated stent may only be retained in position by the outwardly acting pressure of the inflated portions of the stent, although a stent may also be tethered or mechanically anchored. Any disturbance to the stent, for example, deformation of the inflatable stent under high pressure flow may cause the stent to become displaced. Accordingly, an alternative or additional supporting arrangement would improve the structural integrity of the stent, thereby reducing its susceptibility to deformation, displacement and ejection from the working position of the pipe.

Due to material and joining properties of the stent, an inflation pressure, which is great enough to provide sufficient rigidity, may not be possible. Thus, the need for an additional or alternative stiffening arrangement is required.

According to a first aspect, there is provided a method of deploying a stent into a conduit, the stent comprising at least one chamber containing a packing medium when in use and the stent being configurable between a first configuration in which the packing medium in the chamber has a first packing density; and a second configuration in which the packing medium in the chamber has a second packing density, the second packing density being greater than the first packing density, the method comprising the steps of arranging the stent in the first configuration, when relative flexibility is required; and applying a negative pressure differential to one or more of the at least one chamber containing the packing medium to reconfigure the stent into the second configuration, when relative rigidity is required.

In some embodiments, the stent may be subject to a neutral differential pressure such that the stent is pliable and neither inflated nor packed. The neutral configuration may be employed when the stent is in the first configuration (e.g. with a relatively low packing density) such that the stent can be easily introduced and, in some cases, manoeuvred into position. In some embodiments, the packing medium chamber may be part-inflated in the first configuration to allow for manoeuvrability. The stent may be placed into the second configuration before, during or after the stent is in position for use.

It will be understood that providing the stent with a relatively low packing density (which may be zero if the packing medium is yet to be introduced) will allow the stent to be easily flexed and manipulated. This may be useful at least whilst the stent is being introduced into the conduit. Thereafter, the stent may remain with a relatively low packing density whilst it is manoeuvred into position or the packing density may be increased to provide at least some rigidity (and possibly also reduce the dimensions of the stent) whilst the stent is being manoeuvred into position. Such rigidity may help the stent to pass a hole or lesion in the conduit more easily when being deployed. Once in position, the packing density of the stent may be controlled to provide a desired rigidity and/or size required for a particular application.

The stent may comprise at least one lumen and the method may further comprise the step of inflating one or more of the at least one lumen with a fluid.

The stent may comprise a plurality of chambers containing the packing medium and the method may comprise inflating one or more of the plurality of chambers.

The method may comprise the step of inserting the packing medium into the at least one chamber of the stent.

The method may comprise providing the packing medium in the at least one chamber prior to introducing and/or manoeuvring the stent in the conduit.

The method may comprise the step of positioning the stent into a working position within the conduit.

The method may comprise the step of using a deployment arrangement to manoeuvre the stent in the conduit.

The method may comprise the step of removing the deployment arrangement from the conduit, leaving the stent in situ within the conduit.

The method may further comprise the step of removing the stent from the conduit.

The negative pressure differential may be applied to the at least one chamber by an ambient pressure of the conduit. Alternatively or additionally, the negative pressure differential may be applied to the at least one chamber by a vacuum pump.

The at least one chamber suitable for containing the packing medium and/or the chamber containing the packing medium when in use may each be defined as a packing medium chamber. The lumen suitable for inflation with a fluid may be defined as a fluid chamber.

In some embodiments, one or more of the packing medium chambers and the fluid chambers may be the same.

The conduit may be, comprise, or may form a pipe, channel, tube, elongated hollow element or the like.

The conduit may comprise piping, e.g. gas pipe, water pipe, sewage pipe, gas exhaust pipe or the like.

The conduit may comprise a corporeal conduit and/or tubular element, for example, a vein, artery, blood vessel, aorta, intestine, oesophagus, trachea or the like.

The conduit may comprise, contain, or be at least partially filled with a fluid. The fluid may have a flow or pressure. The conduit may be suitable for containment of a fluid, or be suitable for at least partially filling with a fluid.

The conduit may have a wall.

The conduit may comprise one or more working positions. The working position may define an area in which the stent is to be inserted when in use, for example, the working position may correspond to a damaged area or portion of pipe or vein or the like.

When the stent is in the working position within the conduit, the conduit may comprise an upstream side and a downstream side. The upstream side and the downstream side may be defined relative to the stent. The upstream side may be defined as an area upstream, i.e. upstream of the fluid flow, to the stent. The downstream side may be defined as an area downstream, i.e. downstream of the fluid flow, from the stent.

The at least one chamber of the stent may contain the packing medium prior to deploying the stent. The at least one chamber of the stent may be partially filled with the packing medium prior to deploying the stent. The packing medium may be inserted into the at least one chamber of the stent prior to deploying the stent. The packing medium may be inserted into the at least one chamber as part of the deployment step and/or following deploying the stent and/or once the stent has been inserted into the conduit and, optionally, manoeuvred there-within.

The packing medium may comprise one or more of powder, grains, pellets, granules or particles, for example, coffee grounds, coffee granules, grains of rice, sand, gravel or the like.

The packing medium may be provided in a fluid.

The packing medium may comprise a slurry.

The packing medium may comprise one or more geometric shapes/solids with or without optimised packing densities and which are either held in position or free to flow within the chamber.

The packing medium may comprise a compressible solid material (e.g. polystyrene balls).

At the first packing density, the stent may be flexible, i.e. non-rigid, pliable, malleable or the like. At the first packing density, the stent may conform and/or be able to conform to a profile of a surface, e.g. an inner wall of the conduit.

At the second packing density, the stent may be rigid, i.e. non-flexible, non-pliable, non-malleable or the like, at least to some degree. The rigidity and/or flexibility and/or pliability and/or malleability of the stent at the second packing density is advantageously greater than the rigidity of the stent at the first packing density.

It will be understood that the term rigid may be defined as being difficult or impossible to flex, bend or deform during normal use, without the use of power tools or the like. For example, the rigidity or stiffness of the stent may be increased or maximised, when required, for stability and so as to support the lumens such that the stent may bridge various pressure differentials. The flexibility of the stent, when required, may be such as to allow the stent to easily enter and be guided or manoeuvred into position within a conduit.

It will be understood that the term flexible may be defined as being relatively easily flexed, bent or deformed during normal use, without the use of power tools or the like, through the application of small forces, typically achievable during use.

The stent may be deployed with the use of a deployment arrangement.

The stent may be deployed to the working position within the conduit.

The stent may be inserted into the conduit by application of an external force, e.g. pushing from the upstream side of the stent, and/or pulling from the downstream side of the stent.

The stent may be passively deployed into the conduit by allowing the flow of a fluid within the conduit and/or pressure within the conduit to position the stent, e.g. by displacing the stent, unfurling the stent, unrolling the stent or the like.

The stent may be deployed with the use of a tether or umbilical with longitudinal compressive strength and flexibility to allow insertion into a pipe and to achieve an inserted distance.

The stent may be secured on the upstream side of the stent by an anchor arrangement.

The anchor arrangement may be separate to the stent. Alternatively, the stent may comprise an integrated anchor arrangement.

The anchor arrangement may be positioned within the conduit, and/or, at, or in the region of an inlet and/or opening of the conduit and/or at a surface level.

During deployment and/or insertion of the stent into the conduit, the chambers containing the packing medium may be at a neutral or ambient pressure, i.e. at a pressure equal to the surroundings, e.g. the conduit pressure. By such provision, the structure of the chambers containing the packing medium may be non-rigid, flexible, pliable or compliant or the like.

When it is desired for the rigidity of the stent to be increased, e.g. once at or close to the working position, the chamber containing the packing medium may be evacuated of fluid, leaving the packing medium compressed in situ, i.e. the pressure of the chamber may be reduced relative to the ambient pressure, i.e. the conduit pressure.

The stent may be reconfigured to the second configuration to provide a rigid structure before, during or after the deployment process, in which case, the chambers containing the packing medium may be evacuated of fluid, leaving the packing medium compressed in situ prior to, during or after deployment into the conduit.

The stent may be reconfigured from the first configuration to the second configuration by the application of a negative pressure to the stent and/or at least one chamber of the stent, or by returning to atmospheric or lower pressure, relative to the conduit pressure, if the stent is located within a pressurised conduit.

The application of negative pressure may comprise evacuation of fluid (but not the packing medium) from the stent and/or at least one chamber of the stent.

The negative pressure may be applied to the stent and/or at least one chamber by an increased pressure of the conduit above the relative pressure within the chamber. Alternatively or additionally, the negative pressure may be applied to the chamber by a vacuum pump, impeller, fan or the like.

The negative pressure may be applied by a positive force and/or pressure i.e. compression, exerted on the stent and/or at least one chamber from an exterior and/or interior and/or internal passage of the stent and/or chamber.

Alternatively or additionally, the negative pressure may be applied by a negative pressure, i.e. suction, applied onto the stent and/or at least one chamber.

The at least one chamber containing the packing medium may be held under vacuum. By such provision, the packing density of the packing medium may be increased, thus increasing the rigidity of the stent relative to the rigidity prior to evacuation of the at least one chamber.

Additionally or alternatively, one or more of the at least one chamber containing the packing medium may be inflated with a fluid, e.g. air or water.

The packing medium may be inserted into the at least one chamber with the use of an inflation medium. The inflation medium may comprise a fluid, e.g. air or water. The packing medium may be suspended in the inflation medium. The packing medium may be transported by the inflation medium.

After the packing medium has been inserted into the at least one chamber, the inflation medium may be removed from the chamber. By such provision, only the packing medium is left in the at least one chamber.

The at least one chamber may comprise a fluid flow path through which the inflation medium may be removed. The fluid flow path may comprise a tube having an inlet which may comprise one or more holes and/or may comprise a porous member, e.g. fabric, knit, or thread.

A size of the packing medium chamber may be reduced when the negative pressure is applied to the stent and/or at least one chamber of the stent.

The stent may have a diameter. The stent may have an outer diameter and an inner diameter. The diameter, i.e. inner and/or outer diameter may be reduced in the second configuration relative to the first configuration due to application of the negative pressure.

The fluid chambers may be over inflated in the second configuration compared to the first configuration in order to counteract and/or accommodate the reduction in diameter and/or size of the packing medium chamber.

According to a second aspect, there is provided an apparatus for inserting a stent into a conduit, the stent comprising at least one chamber containing a packing medium when in use and the stent being configurable between a first configuration in which the packing medium in the chamber has a first packing density; and a second configuration in which the packing medium in the chamber has a second packing density, the second packing density being greater than the first packing density, the apparatus comprising; a deployment arrangement, the deployment arrangement configured to deploy the stent into a working position in the conduit; and an evacuation arrangement for applying a negative pressure differential to one or more of the at least one chamber containing the packing medium.

The apparatus may be configured to deploy the stent from within the conduit. Alternatively or additionally, the apparatus may be configured to deploy the stent from outside the conduit.

The apparatus may be inserted into the conduit for the deployment of the stent.

The apparatus may be telescopic.

The apparatus may comprise a valve and/or be configured for controlling a valve located on the stent and/or at least one chamber of the stent to allow for controlled insertion of the packing medium and/or fluid.

The deployment arrangement may comprise a separate access conduit which may be configured for the insertion and/or removal of the stent to and/or from the conduit, for example, to and/or from the working position of the conduit.

The access conduit may be telescopic or of rigid or flexible construction. The access conduit may be configured as an arm or umbilical.

The access conduit may be configured to be extended to reach the working position of the conduit and may be configured to deploy the stent.

The access conduit may be controlled by means of mechanical and/or electrical and/or hydraulic and/or pneumatic actuation.

The deployment arrangement may comprise a launch tube which may be disposed on the access conduit. The stent may be inserted into the launch tube prior to deployment.

The deployment arrangement and/or access conduit and/or launch tube may comprise one or more of, an inflation arrangement configured for inflation of one or more of the at least one chambers; a packing medium insertion arrangement configured for the insertion of the packing medium into one or more of the at least one chambers; and the evacuation arrangement.

The deployment arrangement may comprise an anchor arrangement, suitable for securing and/or anchoring the stent in position within the conduit during the deployment process, such that the stent is not displaced, deformed or the like while the reconfiguration step takes place.

The stent may be connected to the anchor arrangement by a suitable high strength attachment means, e.g. cable, chain, cord, rope, rod or the like.

The attachment means may be disconnected from the stent, e.g. the stent may be removed from the anchor once the reconfiguration step has been completed.

The evacuation arrangement may comprise a vacuum pump. Alternatively, or additionally, the evacuation arrangement may comprise an impeller, fan, eductor or the like.

An evacuation pipe may connect and/or form a continuous fluid pathway between the evacuation arrangement and the stent and/or at least one chamber of the stent.

At least a portion of the evacuation arrangement, for example the evacuation pipe, may be disposed on the arm of the deployment arrangement. By such provision, at least a portion of the evacuation arrangement, e.g. the evacuation pipe, may be removed from the conduit after deployment of the stent is complete.

The packing medium insertion arrangement may comprise a fill tube and, optionally, a flow return conduit. In some embodiments, the flow return conduit will complete a flow circuit with the fill tube such that flow of air/fluid may circulate to assist in the efficient transport of the packing medium into the at least one chamber, wherein the packing medium may be captured and retained by a filter. The flow return conduit may be used together with the fill tube in a reverse flow scenario to transport the packing medium out of the at least one chamber of the stent when no longer needed.

In some embodiments, the fill tube and flow return conduit may be constituted by a single tubular.

Advantageously, the packing medium may be introduced using an inflation medium (e.g. air) and, subsequently, the inflation medium may be removed (e.g. evacuated) from the stent to allow for collapse of the stent, for example, for subsequent deployment or recovery of the stent. Thus, although close packing of the packing medium will increase rigidity of the stent it may also reduce an outer diameter of the stent, thereby permitting movement of the stent along a pipe.

The packing medium insertion arrangement may comprise a storage device and/or store which may be used to store the packing medium prior to (and, optionally, after) use. The storage device may be external, i.e. separate to the stent and/or at least one chamber of the stent. Alternatively, or additionally, the storage device may be integral with the stent and/or at least one chamber. The fill tube may transport the packing medium from the storage device and/or store, to one or more of the at least one chamber of the stent. Thus, the fill tube may be configured for transport of the packing medium to one or more of the at least one chamber of the stent.

The method of inserting a stent into a conduit using the deployment apparatus may comprise one or more of the following steps; Insert the stent into the launch tube; Attach the stent to the anchor arrangement on the deployment arrangement and/or umbilical/rod; Deploy the deployment arrangement into the conduit; Insert the stent into the conduit; Open the valve of the stent and/or at least one chamber of the stent; Equalise the pressure in the packing medium chambers containing the packing medium to the conduit pressure, by such provision, the stent is in the first configuration, i.e. the packing medium is not packed and is flexible; Position the stent to the working position in the conduit whilst the stent is in the first configuration; Apply a negative pressure and/or evacuate one or more of the chambers containing the packing medium, thereby reconfiguring the stent to the second configuration, i.e. the stent is rigid; Make fine adjustments to the position of the stent in the conduit if necessary; Inflate the fluid chambers of the stent, if any, with a fluid in order to create a seal against the wall of the conduit; Close the valve of the stent and/or at least one chamber of the stent; Optionally, detach the stent from the anchor arrangement on the deployment arrangement; Optionally, remove/recover the stent; Optionally, leave the stent and/or a sealant in situ; Perform remedial work on the conduit if necessary; Remove the deployment arrangement from the conduit if necessary.

However, it will be understood that not all of the above steps are compulsory and some of the above steps are optional. At least some of the steps may be performed in any order.

The method of removing the stent from the conduit using the deployment apparatus may comprise one or more of the steps of; Insert the deployment arrangement into the conduit if not present in the conduit; Dock the launch tube with the stent; Attach the anchor arrangement on the deployment arrangement to the stent; Open the valve of the stent and/or at least one chamber of the stent; Deflate the fluid chambers of the stent; Apply a positive pressure to the packing medium chambers, thereby reconfiguring the stent to the first configuration, i.e. the stent is flexible; Close the valve of the stent and/or at least one chamber of the stent; Remove the stent from the conduit by extracting the deployment arrangement from the conduit; Detach the stent from the anchor arrangement on the deployment arrangement; Remove the stent from the launch tube.

According to a third aspect, there is provided a stent comprising at least one chamber for containment of a packing medium; and wherein the stent is configurable between a first configuration in which the packing medium in the chamber has a first packing density and a second configuration in which the packing medium in the chamber has a second packing density; and wherein in the second packing density is greater than the first packing density.

The stent may comprise a lumen. The lumen may be suitable for inflation with a fluid. The chamber suitable for containing the packing medium and/or the chamber containing the packing medium may be defined as a packing medium chamber. The lumen suitable for inflation with a fluid may be defined as a fluid chamber. The packing medium chamber and the fluid chamber may be the same.

Advantageously, the at least one chamber containing a packing medium may provide a longitudinal rigidity and/or strength to the stent. Alternatively or additionally, the rigidity and/or strength of the stent may be controlled with variable pressure applied to the at least one chamber and/or stent and/or by applying a vacuum or partial vacuum to the at least one chamber and/or stent.

In use, i.e. when a negative pressure differential is applied, the packing medium filled chamber may form, provide or be a reinforcing member for the stent, e.g. a rib.

By such provision ease of inserting, positioning and/or repositioning the stent may be increased relative to a non-rigid stent, i.e. a stent without a reinforcing member.

A non-rigid, flexible stent may become misshaped and/or deformed due to forces and/or pressure exerted by a fluid flow. The fluid flow may introduce a pressure differential in different regions of the stent, e.g. on an upstream side and/or on a downstream side. Such pressure differentials may cause the stent to become displaced, deformed, or ejected from an operating or working position.

Increasing the rigidity of the stent may reduce, limit or prevent this displacement, deformation or ejection of the stent.

The stent may be used for stemming, restricting, stopping, reducing or limiting the flow of a fluid within the conduit. The stent may be used for controlling the flow of a fluid contained within the conduit.

The stent may be used for diverting the flow of fluid. The stent may be used to remove fluid from at least a portion of a conduit, e.g. a conduit wall. The stent may be used to remove contact between the fluid and a portion of a conduit, e.g. the conduit wall.

The stent may be annular, i.e. may comprise an annulus.

The stent may comprise a central shaft which may comprise one or more lumen and/or chambers, e.g. packing medium chambers and/or fluid chambers.

The central shaft may be defined or formed by a central orifice of the annulus.

The stent may comprise a stopper configured for selective blocking of a flow path (e.g. central orifice) through the stent when the stopper is packed with the packing medium. For example, the stent and stopper could be configured to form a solid two-part stopper to block flow through the stent orifice. This may be achieved, for example, by the stent annulus having an inner profile in a cone like shape and the stopper have a complementary cone shape when packed with packing medium (e.g. when provided with packing medium and a differential pressure is applied to increase packing density).

The stopper may therefore be configured to act like a wedge, such that insertion into the inner profile of the stent promotes further contact of the stent with the inner pipe wall thereby ensuring flow through the pipe is blocked.

The structure of the stent may be formed, at least in part, by the evacuation of one or more packing medium chambers, which may be oriented in a longitudinal direction along the length of the stent, to increase packing density and thereby cause rigidity. In a non-evacuated, or partially-evacuated condition, the stent may lack rigidity, i.e. be flexible, soft, pliant, malleable, bendable or the like.

The stent may be used within, or suitable for use within gas and/or water pipes and/or sewage pipes, for example, for controlling fluid escape, allowing remediation work, whilst continuing to allow the fluid to flow.

Alternatively the stent may be used in medical applications, for example as a corporeal stent for use in, e.g a vein, artery, blood vessel, aorta, intestine, oesophagus, trachea or the like.

In use, the stent may be positioned in a working area or working position. The working position may be an area or volume, e.g. of the conduit. The working area or working position may define the area in which the stent is inserted when in use, for example, a pipe, or a damaged area of pipe, vein, damaged portion of vein or the like.

The stent may have a length The stent may have a cross sectional profile. The cross sectional profile of the stent may be generally annular or circular. Alternatively, the cross sectional profile may be polygonal, e.g. triangular, square, pentagonal, hexagonal, heptagonal, octagonal or the like.

The stent may have an outer diameter. The stent may have an inner diameter. The distance between the outer diameter and the inner diameter may define a thickness of the at least one chamber.

Varying the dimensions of the stent, i.e. outer diameter and/or inner diameter and/or chamber thickness may allow for a bespoke fit to a specific conduit and/or may alter a flow rate and/or flow characteristics of a fluid flowing through the stent.

The stent may comprise a first end and may comprise a second end. The second end may be distal to the first end. The first end may be disposed on the upstream side when in use. The second end may be disposed on the downstream side when in use.

The stent may comprise at least one manifold which may be disposed on at least one of the first end of the stent and the second end of the stent.

The stent, central shaft and/or chamber may comprise a wheel or other suitable friction reducing device which may aid positioning or repositioning etc. of the stent within the conduit.

The stent may comprise a bypass pipe which may divert the flow of fluid away from a portion of the conduit, thereby stopping the flow of fluid within the bypassed region. The bypassed region of the conduit may then be drained, evacuated, emptied or the like. Remedial work or repair may be performed on the bypassed region.

The stent may comprise one or more packing medium chambers and none, one or more fluid chambers.

The stent may comprise, or be formed of a plurality of chambers which may be arranged in an annular shape around a circumference of the stent.

At least one of the one or more chambers may be disposed circumferentially around the stent, e.g. around the annular profile of the stent.

At least one of the one or more chambers may be disposed radially inwards of the annulus of the stent.

At least one of the one or more chambers may be disposed radially outwards of the annulus of the stent.

The plurality of chambers may be arranged in a matrix formation, i.e. the chambers may be arranged in a plurality of concentric rings of increasing radius. In an embodiment in which the chambers are arranged in a matrix formation, the packing medium chambers may be arranged in an alternating pattern such that a packing medium chamber is located circumferentially and radially adjacent to a fluid chamber.

By such provision, the packing medium chambers and fluid chambers may be arranged in a checkerboard arrangement.

At least one chamber may be oriented in a longitudinal direction, i.e. axially, along the length of the stent.

At least one chamber may be arranged helically around the stent, i.e. varying circumferentially around the annulus with varying longitudinal position.

In use, at least one chamber containing the packing medium may be oriented in a longitudinal direction along the length of the stent.

The chamber may have a length.

The chamber may have a cross sectional profile.

The cross sectional profile of the chamber may be generally circular. Alternatively, the cross section profile of the chamber may be polygonal, e.g. triangular, square, pentagonal, hexagonal, heptagonal, octagonal or the like.

The one or more chambers may be, form or take the shape of different shapes and/or sizes. Alternatively or additionally at least some of the one or more chambers may be, form or take the shape of the same shape and/or size.

The one or more chambers may form a lattice structure, e.g. a honeycomb structure.

At least one of the chambers may contain the packing medium when in use or prior to use. All of the chambers may contain the packing medium in use or prior to use. Alternate chambers, i.e. every other chamber, may contain the packing medium when in use or prior to use.

The at least one chamber of the stent may contain the packing medium prior to use, e.g. prior to deploying the stent. The at least one chamber of the stent may be at least partially filled with the packing medium prior to use, e.g. prior to deploying the stent. The packing medium may be inserted into the at least one chamber of the stent prior to use, e.g. prior to deploying the stent. The packing medium may be inserted into the at least one chamber as part of the deployment step and/or following deploying the stent and/or once the stent has been inserted into the conduit.

Each of the chambers may be discrete, i.e. separate from each other. Alternatively or additionally, one or more chamber may be connected together and/or may share a fluid flow path, i.e. be fluidly connected to each other.

The one or more chambers containing the packing medium, i.e. the packing medium chambers may occupy a length substantially equal to the length of the stent.

The one or more chambers containing the packing medium, e.g. the packing medium chambers may occupy a length less than the length of the stent.

The length of at least one chamber may be equal to, or substantially equal to the length of the stent. Alternatively or additionally, the length of the at least one chamber may be less than the length of the stent.

At least one of the at least one chambers may comprise a valve. The valve may be suitable and/or configured for the application of and/or applying a negative pressure. Application of a negative pressure and/or evacuation of the at least one chamber may reconfigure the stent from the first configuration to the second configuration.

The at least one chamber may comprise one or more valves suitable for the insertion and/or removal of the packing medium and/or a fluid.

The stent may comprise one or more continuous fluid pathways, which may connect at least one chamber to at least one of the first and second ends of the stent and/or at least one manifold of the stent.

Some or all of the chambers may be inflated. The chambers may be inflated in an alternate arrangement, i.e. every other chamber is inflated. This may provide a degree of structure and/or rigidity which may aid deployment, and which may be performed prior to final inflation or deflation once in the working position.

The one or more chambers may comprise one or more walls.

The one or more chambers may comprise one or more baffles The one or more baffles may separate one or more chambers from each other.

The one or more baffles may limit or prevent the spread and/or migration of packing medium within the one or more chambers, for example, to prevent all the packing medium from gathering at one end of the one or more chambers. The one or more baffles may ensure even distribution of the packing medium in the at least one chamber.

The one or more baffles may be oriented generally radially.

The one of more baffles may provide strength and/or rigidity to the stent and/or chamber, for example radial strength.

The one or more baffles and/or walls may separate at least one region of the stent and/or chamber from another region of the stent.

The stent and/or chambers of the stent and/or baffles and/or chamber walls may comprise an internal support structure, which may assist the stent and/or chambers to retain a shape. The internal support structure may comprise struts, ribs, cord or the like.

The one or more chambers may be configured to hold, withstand or support one or more of, pressure, vacuum, packing medium, inflation medium, fluid or the like.

One or more of the one or more chambers may be hollow. Alternatively, one or more of the one or more chambers may be solid.

The one or more chambers may comprise a quilt structure, which may support the packing medium. The quilt structure may comprise two or more discrete layers in a sandwich construction. For example, the layers may form pockets, in which, the packing medium may be supported. Adjacent pockets may be interconnected and may comprise a porous membrane, which may permit the transfer of fluid, e.g. air, pressure, negative pressure, vacuum or the like whilst preventing the transfer of the packing medium between adjacent pockets. The porous membrane of the pockets may be formed of felt or knit or the like. The porous membrane may comprise one or more pores or holes.

The chambers and/or pockets containing the packing medium may be at positive pressure, negative pressure, vacuum, neutral pressure, under pressure or the like, relative to the ambient pressure of the working area, e.g. conduit pressure.

The chambers may be configured so that a collapse plane is provided, i.e. a plane in which the chambers may collapse when not containing the packing medium may be one or more of horizontal, vertical, circumferential or radial to an axis of the stent. By such provision, a rigid member may be produced which has a desired strength and/or rigidity in a required and/or desired orientation and/or direction.

The stent may be provided in a form that is suitable for containing the packing medium. In some embodiments, the stent may comprise and/or contain and/or be at least partially filled with the packing medium when provided for use.

The stent or a chamber of the stent may contain a compressible gas.

The stent or a chamber of the stent may contain a packing medium, which may be an incompressible substance, e.g. a liquid and/or a solid.

The packing medium may comprise one or more of powder, grains, pellets, granules, particles or the like. The packing medium may comprise a plurality of powder, grains, pellets, granules, particles or the like. The packing medium may comprise a plurality of different types of powder, grains, pellets, granules, particles or the like.

The packing medium may comprise coffee grounds, coffee granules, grains of rice, sand, gravel or the like.

The packing medium may pack to form a rigid structure.

The packing medium, may be non-rigid or flexible when at a pressure which is ambient, i.e. equal to the pressure of its surroundings, or greater than ambient pressure.

The packing medium may be, form or take the shape of different shapes, for example, spheres, cubes, polyhedron, polytopes, permutohedrons or the like which may be of varying sizes. In some embodiments, at least some of the packing medium may be the same size and/or shape.

Varying the characteristics of packing medium, e.g. size, volume, shape, or the like may vary the packing density.

The individual particles, e.g. powder, grains, pellets, granules or particles or the like may be of a size, e.g. diameter, greater than the size, e.g. diameter of the pores of the porous membrane. By such provision, the particles will not pass through the porous membrane, while a fluid, e.g. the inflation medium, will pass through the porous membrane. By such provision, the packing medium can be retained in the packing medium chamber during and/or after the evacuation process.

The fluid chamber may be inflatable and/or configured to be inflatable with a fluid when in use. The fluid chamber may be inflated and/or at least partially filled with a compressible gas and/or an incompressible fluid. The fluid may be, or may comprise at least one of air, carbon dioxide, nitrogen, helium, neon, argon or the like, or any mixture thereof. The fluid may be, or may comprise at least one of water, oil or the like, or any mixture thereof.

The stent and/or at least one chamber of the stent may comprise a packing medium inlet. The stent and/or at least one chamber of the stent may comprise a fluid inlet. The packing medium inlet and the fluid inlet may be the same. The packing medium inlet and/or the fluid inlet may comprise a valve. The packing medium inlet may be configured for and/or be suitable for the insertion of the packing medium into the at least one chamber. The fluid inlet may be configured for and/or be suitable for the insertion of the fluid into the at least one chamber.

The stent and/or at least one chamber of the stent may comprise a packing medium outlet. The stent and/or at least one chamber of the stent may comprise a fluid outlet. The packing medium outlet and the fluid outlet may be the same. The packing medium outlet and/or the fluid outlet may comprise a valve. The packing medium outlet may be configured for the removal of at least a portion of the packing medium from the at least one chamber. The fluid outlet may be configured for the removal of at least a portion of the fluid from the at least one chamber. The packing medium outlet and/or the fluid outlet may be provided on an inner surface, an outer surface or an end surface of the stent. Thus, the packing medium and/or fluid may be removed from the inner, outer or end surface of the stent.

The outlet of the chamber may be connected to at least one of the manifold, the first end of the stent or the second end of the stent.

One or more chambers may contain a fluid, for example, air, compressed air, carbon dioxide, nitrogen, helium, or other suitable gas or the like. Alternatively or additionally, one or more chambers may contain a liquid, for example, water or oil.

The packing medium may be held in or supported by a lattice structure, which may be disposed within the chamber. The lattice structure may be, or take the form of a sponge, honeycomb structure or the like. The lattice structure may be compressible. By such provision, the packing medium may be evenly distributed throughout the chamber, and may not collect or gather in a single location, e.g. one end of the chamber.

At the first packing density, the stent may be flexible, i.e. non-rigid, pliable, malleable or the like. At the first packing density, the stent may conform and/or be able to conform to the profile of a surface, e.g. a conduit.

At the second packing density, the stent may be rigid, i.e. non-flexible, non-pliable, non-malleable or the like. The rigidity of the stent at the second packing density is greater than the rigidity of the stent at the first packing density.

The packing density of the packing medium may be increased by reducing the volume of the chamber containing the packing medium, i.e. the volume of the chamber in the first configuration may be greater than the volume of the chamber in the second configuration.

Reducing the volume of the chamber containing the packing medium may compress the packing medium contained in the chamber.

The volume of the chamber containing the packing medium may be reduced by applying a negative pressure on the chamber and/or the stent.

Applying a negative pressure on the chamber and/or the stent may allow the stent to be changed and/or reconfigured from the first configuration to the second configuration.

Compressing the packing medium contained within a chamber in this manner, e.g. by applying a negative pressure and/or vacuum to the chamber, may result in a rigid structure.

It should be understood that the features defined above or described below may be utilised, either alone or in combination with any other defined feature, in any other aspect or embodiment or to form a further aspect or embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 shows a perspective view of a stent comprising multiple chambers containing a packing medium according to a first embodiment; Figure 2 shows the stent of Figure 1 in (a) a first configuration; and (b) a second configuration; Figure 3 shows a sectional view of portion of the stent of Figure 1 showing the chambers in (a) the first configuration; and (b) the second configuration: Figure 4 shows sectional views of the profile of a portion of a stent according to different embodiments in (a) to (c); Figure 5 shows sectional views of a portion of a stent according further embodiments in (a) and (b); Figure 6(a) to (c) shows sectional views of different embodiments in which the chambers have different shapes; Figure 7 shows a stent according to an embodiment in (a) a first configuration; and (b) a second configuration; Figure 8 shows a stent according to an embodiment in use within a conduit; Figure 9 shows a stent in use within a conduit according to an embodiment in which a bypass pipe has been installed; Figure 10 shows a stent in use within a conduit according to a further embodiment in which a bypass pipe has been installed; Figure 11 shows a deployment arrangement deploying a stent according to a second aspect of the invention; Figure 12 illustrates a flow diagram for a method of deploying a stent into a conduit, in accordance with embodiments of the invention; Figures 13(a)-(c) show annular cross-sections of a stent according to an embodiment of the invention, in three different configurations; and Figure 14 illustrates a control arrangement for a stent configured in accordance with Figure 13(c) for movement within a conduit.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring first to Figures 1 and 2 of the accompanying drawings, there is shown a stent comprising multiple chambers containing a packing medium.

As shown in Figure 1, the stent, generally denoted 1, comprises a plurality of packing medium chambers 2 suitable for the containment of a packing medium, and a plurality of fluid chambers 4, suitable for inflation with a fluid. The packing medium is a powder. However, it will be understood that one or more of powder, grains, rice, pellets, granules or particles or the like can be similarly used.

The stent 1 has a length L. The packing medium chambers 2 run the full length of the stent 1, i.e. the chambers 2 occupy a length equal to length L. However, it will be understood that the packing medium chambers 2 may occupy a length less than the length of the stent L, for example, as shown at 2a. It will be understood that the stent 1 may comprise a number of packing medium chambers of different lengths 2, 2a.

In the embodiment shown, the stent 1 comprises eight packing medium chambers 2, each of which occupy a length equal to the length L of the stent 1. In other embodiments, any number of packing medium chambers 2 may be provided. The eight packing medium chambers 2 are evenly distributed around the circumference of the annulus of the stent 1 such that the cross sectional profile of each of the packing medium chambers 2 is the shape of an annulus sector.

In another embodiment, the packing medium chambers are truncated as shown at 2a, such that each truncated chamber 2a occupies a length which is less than the length of the stent 1. The stent 1 may comprise a plurality of truncated chambers 2a.

The truncated chambers 2a may be distributed radially and/or circumferentially and/or longitudinally along the stent 1. The truncated chambers 2a may all occupy the same truncated length. In some embodiments, the truncated chambers 2a may occupy different lengths. The size and/or shape and/or length of the chambers 2 and/or truncated chambers 2a may be varied in order to provide specific structural properties, for example, flexibility, rigidity, pliability, axial strength or the like. Alternatively or additionally, the size and/or shape and/or length of the chambers 2 and/or truncated chambers 2a may be varied to suit specific properties of the conduit and/or working area, for example, to fit around existing infrastructure of the conduit and/or working area, for example, the position of a valve, joint, bend or the like.

The stent 1 further has tubes 6, 8 connected, respectively, to chambers 2, 4. A single packing medium fill tube 6 is connected to two packing medium chambers 2 and transports the packing medium from an external source (not shown) to the two packing medium chambers 2. In other embodiments, a packing medium fill tube 6 may be connected to all packing medium chambers 2 or each packing medium chambers 2 may be connected to a separate packing medium fill tube 6. In an embodiment, the packing medium is inserted into the packing medium chambers 2 with the use of an inflation medium, wherein the inflation medium is a suitable fluid such as air. The packing medium is suspended in the inflation medium and transported by the inflation medium into the packing medium chambers 2. In this way, the packing medium is forced into the packing medium chambers 2 by the flow of the inflation medium fluid. Advantageously, the inflation medium will inflate the packing medium chambers 2 during the packing medium filling process, ensuring that the packing medium evenly fills each packing medium chamber 2. In order to allow the inflation medium to transport the packing medium into the packing medium chambers 2, the packing medium chambers 2 contain a suitable outlet which provides a continuous fluid flow path for the inflation medium to flow through the packing medium chambers 2, distributing the packing medium in the process. The outlet of the packing medium chambers 2 comprises a suitable means for permitting the flow of the inflation medium, whilst not permitting the passage of the packing medium, for example a porous membrane, in which the holes of the porous membrane are smaller than the size of the particles of the packing medium, thereby restraining the packing medium whilst permitting passage of the inflation medium. The porous membrane comprises a fine mesh for example, fabric, or metallic mesh. However, it will be understood that any suitable sieve or porous membrane could be used.

A single fluid fill tube 8 is shown connected to two fluid chambers 4 to inflate the fluid chambers 4 with a fluid. In other embodiments, a single fluid fill tube 8 may be connected to all fluid chambers 4 or each fluid chamber 4 may be connected to a separate fluid fill tube 8. When inflated, the fluid chambers 4 form the structure of the stent 1, while the packing medium chambers 2 provide structural supports. The fluid chambers 4 form the general shape of the stent 1. The fluid is typically air. However, it will be understood that other suitable gases may be used, for example, carbon dioxide, nitrogen, helium, argon, neon or the like. For clarity, the fill tubes 6, 8 are shown here to each only connect, respectively, to two chambers 2, 4, however, it will be understood that the fill tubes 6, 8 may be connected to all of the chambers to be filled with a powder/inflated. Advantageously, a manifold (not shown) may connect a single packing medium fill tube 6 to each of the packing medium chambers 2, and a separate manifold may connect a single fluid fill tube 8 to each of the fluid chambers 4. By such provision, the manifolds will evenly distribute the fluid / packing medium from a single inlet 6, 8, to a plurality of chambers 2, 4.

The chambers 2, 4 each have a cross-sectional profile of an annular sector. However, it will be understood that the cross-sectional profiles of the chambers 2, 4 may be any suitable shape, for example, circular, triangular, square, rectangular, pentagonal, hexagonal, heptagonal, octagonal or the like. In which case, the stent 1 may comprise an outer layer and an inner layer, forming a generally annular cylinder. The chambers 2, 4 may be disposed within inner and outer diameters of the annulus.

The chambers 2, 4 are shown in FIG. 1 to occupy the full length of the stent L. However, it will be understood that a plurality of chambers may be disposed along the length of the stent L. In which case, the chambers may be positioned adjacent and in series along the axial length, L. Adjacent chambers may be interconnected, or may be discrete. A continuous fluid flow path may connect adjacent chambers 2, 4.

The stent 1 has an outer diameter OD and an inner diameter ID. The outer diameter OD is the outermost diameter of the stent 1, i.e. the outer layer of the annular cylinder. The inner diameter ID is the innermost diameter of the stent 1, i.e. the inner layer of the annular cylinder. It will be understood that varying the diameter of the outer diameter OD, and/or inner diameter ID, and/or volume of the chambers 2, 4 will allow for varying conduit diameters and/or varying flow rates through the stent 1.

Referring also to Figure 2, the stent 1 is shown in a first (flexible) configuration (a); and a second (rigid) configuration (b). In the first configuration shown in Figure 2(a), the stent 1 is in an expanded state and the packing medium has a first (loose) packing density. In the second configuration shown in Figure 2(b), the stent 1 is in a compacted state and the packing medium has a second (tight) packing density. In the compacted state of the second configuration, a negative pressure differential has been applied to the packing medium chambers 2, causing the volume of the packing medium chambers 2 to reduce, thereby causing the packing medium to become compacted, increasing the packing density of the packing medium disposed within the chamber 2 such that the packing density in the second configuration is greater than the packing density in the first configuration.

Advantageously, in the first configuration, the packing medium chambers 2 are flexible, typically with a stiffness optimal to support positioning of the stent, and allowing the stent 1 to be deployed into the conduit and conform to the profile of the conduit and/or working position. In the second configuration, the inflation medium is extracted, causing the packing medium to become compacted, thereby increasing the rigidity of the packing medium chambers 2, typically with a stiffness to position the stent and provide a longitudinal rigidity and/or strength to the stent 1.

The negative pressure differential is applied by applying suction through the fill tube 6. It will be understood that the negative pressure may be applied with the use of a vacuum pump, or other suitable pump to remove the inflation medium or ambient air from the chambers 2, 4. Alternatively or additionally, an external pressure may be applied to the outer diameter OD walls and/or internal diameter ID walls of the stent 1 in order to expel the inflation medium from the chambers 2, 4. In an embodiment in which the ambient pressure of the conduit is higher than the internal pressure in the packing medium filled chamber 2, then this pressure differential may be used to apply a pressure onto the internal diameter ID walls of the stent 1 without the need to apply an additional pressure and/or vacuum. In this embodiment, an outlet valve of the packing medium chamber 2 is opened, and the pressure differential between the conduit pressure and the packing medium chamber 2 pressure will cause the inflation medium to be expelled from the packing medium chamber 2. It can be seen that the outer diameter OD of the stent 1 in the first configuration is larger than the outer diameter OD of the stent 1 in the second configuration. This need not always be the case. For example, the reduction in volume of the packing medium chambers 2 may be taken up by further inflation of the fluid chambers 4 such that the stent in a rigid configuration may have the same or a greater outer diameter as the stent in a flexible configuration.

Referring now to Figure 3, there is shown cross sectional profiles of a portion of the stent 1 showing two packing medium chambers 2 and two fluid chambers 4 in the first configuration (a) and the second configuration (b). In the second configuration, the packing density of the packing medium is increased relative to the first configuration. Consequently, the size of the packing medium chambers 2 is reduced in the second configuration relative to the first configuration. It will be understood that reconfiguring the stent 1 from the first configuration to the second configuration will cause the outer diameter OD to reduce, and inner diameter ID of the stent 1 to increase, i.e. the thickness reduces. It will be further understood that the fluid chambers 4 may be over inflated in the second configuration compared to the first configuration in order to counteract and/or accommodate the reduction in size of the packing medium chamber 2 and ensure / maintain contact between the outer surface of the stent 1 and the walls of the conduit.

Figure 4 shows embodiments of the stent 1 having different arrangements of the packing medium chambers 2. Figure 4(a) shows the stent 1 comprising the chambers 2, 4 according to the first aspect as described above and shown in Figures 1 to 3. Figure 4(b) shows another embodiment of a stent 11 in which packing medium chambers 12 are disposed on an external surface 16 of the stent 11. Advantageously, this arrangement permits the packing medium chambers 12 to be retrofitted to an existing inflatable stent and/or may reduce manufacturing effort since the packing medium chambers 12 may be adhered to the external surface of the stent 11.

Furthermore, the sizes of the packing medium chambers 12 may be varied such that a bespoke fit can be provided to suit a specific conduit, for example, if a conduit is oval in cross section, the size of the packing medium chambers 12 may be varied at different positions around the circumference of the stent 11 in order to ensure appropriate fit within the conduit.

Figure 4(c) shows a further embodiment of a stent 21 in which the packing medium chambers 22 are disposed on an internal surface 28 of the stent 21. Advantageously, this arrangement permits the packing medium chambers 22 to be retrofitted to an existing inflatable stent and/or may reduce manufacturing effort since the packing medium chambers 22 may be adhered to the internal surface 28 of the stent 21. Furthermore, the location of the packing medium chambers 22 on the interior of the stent in this manner may help to ensure a suitable seal between the outer walls of the stent and the conduit and/or may aid in controlling the flow of fluid within the conduit, for example, by reducing turbulence of the flow by providing fluid channels or pathways between adjacent packing medium chambers 22.

Referring now to Figure 5, there are shown portions of further possible embodiments of the stent. Figure 5(a) shows a portion of a stent 31, which comprises a plurality of packing medium chambers 32 and fluid chambers 34 which are arranged in a checkerboard arrangement comprising two rows of chambers 32, 34. The chambers 32, 34 are arranged in an alternating pattern such that a packing medium chamber 32 is located circumferentially and radially adjacent fluid chambers 34. Figure 5(b) shows a similar checkerboard arrangement as shown in Figure 5(a) in which like components are shown incremented by 10. The arrangement of Figure 5(b) comprises three rows of chambers 42, 44.

Advantageously, the arrangements in Figure 5 permit increased strength and or rigidity of the stent 1 by providing a greater number of packing medium chambers 2 in a given cross sectional area of the stent 1. The increased number of packing medium chambers may further provide increased torsional rigidity to the stent 1.

Referring now to Figure 6, there are shown some possible shapes of the packing medium chambers. Figure 6(a) shows the packing medium chamber 2 according to the first aspect as described above and shown in Figures 1 to 3. In this embodiment the cross-sectional profile P of the packing medium chamber 2 is generally the shape of an annular sector. Figure 6(b) shows a packing medium chamber 52 which comprises a cross-sectional profile P which is generally triangular in shape. Figure 6(c) shows a packing medium chamber 62 which comprises a cross-sectional profile P which is generally circular in shape. It will be understood that the cross-sectional profile P of the packing medium chambers may take the form of a variety of other shapes, for example, square, pentagonal, hexagonal, heptagonal, octagonal or the like. It will also be understood that in an embodiment comprising a plurality of packing medium chambers, the shapes of the cross-sectional profiles P of the packing medium chambers may vary. It will also be understood that the shape of the cross-sectional profile of the fluid chambers may vary similarly, for example, the fluid chambers may be circular, triangular, square pentagonal, hexagonal, heptagonal, octagonal or the like and the shapes of the cross-sectional profiles of the fluid chambers may vary.

Referring now to Figure 7, there is shown a further embodiment of a stent 71 comprising a plurality of packing medium chambers 72 and a plurality of fluid chambers 74, both of which comprise a cross-sectional profile P which is generally hexagonal in shape. By such provision the packing medium chambers 72 and the fluid chambers 74 form a honeycomb lattice structure. Advantageously, this form of structure may provide increased structural strength and/or rigidity of the stent 71 for a given size. Additionally, the hexagonal cross-sectional shape of the packing medium chambers 72 may be positioned in a closer packing arrangement with minimal or no dead-space between chambers 72, 74. By such provision, the number of packing medium chambers 72 may be maximised for a given cross-sectional area of the stent 71.

Referring now to Figure 8, there is shown an embodiment of the present invention according to an aspect in which a stent 101 has been inserted into a conduit C. In this embodiment, the conduit C is a plumbing type disposed below the surface of the ground G. A fluid F flows through the conduit C in a direction illustrated by the arrows. The fluid may comprise a gas or a liquid as used in, for example, conventional plumbing, sewage or gas transport.

Packing medium chambers 102 provide structural rigidity to the stent 101 while fluid chambers 104 are inflated sufficiently such that the outer diameter OD of the stent 101 is substantially equal to the internal diameter of the conduit C such that a close fit and fluid tight seal is provided between the stent 101 and the wall of the conduit C. It will be understood that the stent 101 may be of a solid construction so as to completely block the conduit and stop the flow of fluid F. In some embodiments, the stent 101 may comprise a through bore, i.e. be annular in cross--section, such that the flow of fluid F can be restricted, for example, to protect a damaged region of the conduit C from the fluid F. In other embodiments, a bypass pipe (shown in Figures 9 and 10) may be provided in order to divert the flow of fluid F past a section of the conduit C. The stent 101 may be of a similar construction to any of the stents described above.

An apparatus 100 disposed on a surface of the ground G permits the deployment and insertion of the stent 101 into the conduit C. The apparatus 100 may further permit communication between an operator located at the surface and the stent 101, for example, telemetry, signals or the like detected on the stent 101. The apparatus 100 comprises inflation tubes 106, 108 for the insertion of the inflation medium and packing medium into the packing medium chambers 102 and inflation of the fluid chambers 104.

The apparatus 100 comprises a deployment arm 124 in the form of a tether, umbilical or rod for the physical insertion of the stent 1 into the conduit C. The apparatus 100 comprises an anchor arrangement 126, which in an embodiment is disposed on the deployment arm 124. The anchor arrangement 126 comprises an eye bolt or other suitable attachment means which is fixedly attached to the deployment arm 126. The stent 101 connects to the anchor arrangement 126 via a suitable high strength connection 128 such as a cable, cord, rope or the like.

The stent 101 may further comprise a light source and/or optical communication means, for example, a camera, in order to allow the operator to conduct a visual inspection of the interior of the conduit C and/or to identify when the stent 101 is in the correct working position. Such signals e.g. electrical and video and/or audio signals may be transferred between the stent 101 and the apparatus 100 through a connection cable or umbilical, which may be unitary with at least one of the inflations tubes 106, 108. In some embodiments, a separate umbilical may be used for the transfer of signals.

The deployment arm 124, inflation tubes 106, 108 and optional umbilical connect the apparatus 100 to the stent 101 through an access port 122 in the conduit C. The access port may comprise a valve or may merely be a hole in the conduit C which may be cut or drilled prior to inserting the stent 101 into the conduit C. An access tunnel 110 may be provided between the surface of the ground G and the access port 122 of the conduit C. The access tunnel 110 may comprise a prebuilt access, e.g. an access tube comprising a manhole cover or inspection hatch or the like, or access may be dug through the ground G prior to inserting the stent 101 in the conduit C. Although the conduit C is shown in Figure 8 as being disposed below the ground G, it will be understood that the conduit could be above ground, underwater or the like.

Referring now to Figure 9 and 10, there is shown further embodiments of the invention, wherein two stents 201 have been deployed into the conduit C either side of a working area 230, and a bypass pipe 232 has been inserted into each stent 201, thereby causing the flow of fluid F to pass along the bypass pipe 232 and be diverted away from the conduit C, leaving the working area 230 which can be evacuated, depressurised, emptied or the like, e.g. for the repair of the working area 230. The bypass pipe 232 may be deployed temporarily to allow remedial works to take place on the working area 230. In some embodiments, the bypass pipe 232 may be installed as a permanent fixture.

The bypass pipe 232 is shown in Figure 9 to travel above the ground G in order to allow access to the flow of fluid F within the bypass pipe 232, for example, for extracting samples, conducting measurements or the like. It will also be understood that the bypass pipe 232 may be located below the ground G, for example, in a custom built trench. Alternatively, as shown in Figure 10, the bypass pipe 232 may not leave the conduit C and may be used to isolate the walls of the conduit in the working area 230 from the fluid flow F, for example, if corrosion or other damage has occurred in the working area 230.

It will be understood that such a bypass pipe 232 may be used to extract and/or divert the flow of fluid F from the conduit C and to a separate pipe, vessel, container or the like In such an embodiment, only a single stent 201 may be required.

The bypass pipe 232 may be transparent, or may comprise a window or inspection hatch 234 to allow for visual inspection of the flow of fluid F. The bypass pipe 232 may comprise a valve 236 to allow for extraction and/or insertion of samples into the fluid F flow.

As shown in Figure 9, on either side of the working area 230, each stent 201 is connected to a control apparatus 200 comprising inflation tubes 206, 208 for the insertion of the inflation medium and packing medium into the packing medium chambers and the fluid chambers, respectively.. The inflation tubes 206, 208 are routed through the ground G adjacent to and on either side of the bypass pipe 232. A similar arrangement would be employed for each stent 201 in Figure 10, although only one control apparatus 200 is shown.

Now referring to Figure 11, there is shown a deployment apparatus according to the second aspect of the present invention The deployment apparatus 300 is disposed on the surface of the ground G and comprises a deployment arm 324, which is suitable for extension through an access tunnel 310, through access port 322 and into the conduit C. In this embodiment, the deployment arm 324 is telescopic and is suitable for insertion and extension within the conduit C. Attached to the deployment arm 324, is an anchor arrangement 326. The anchor arrangement 326 comprises an eye bolt or other suitable attachment means which is fixedly attached to the deployment arm 326. The stent 301 is connected to the anchor arrangement 326 via a suitable high strength connection 328 such as a cable cord, rope or the like. Disposed on a distal end of the deployment arm 324 is a launch tube 340. In an embodiment, the launch tube fits within the central passageway of the stent 301. The launch tube may comprise a cam arrangement which may lock onto the stent 301 by means of friction fit, or push fit or the like. The cam arrangement may apply a radially outward force on the internal face of the stent 301, thereby ensuring a secure connection between the launch tube 340 and the stent 301. In such an arrangement, the launch tube 340 may position the stent 301 in the working position of the conduit C, and then activate or deactivate the cam arrangement such that the launch tube 340 releases its grip on the stent 301, thereby leaving the stent 301 in the working position when the launch tube 340 is removed.

The deployment arm 324 may comprise fill tubes 306, 308. For example, the deployment arm 324 may support and/or house the fill tubes 306, 308.

The deployment apparatus 300 comprises a packing medium fill arrangement, fluid fill arrangement and evacuation arrangement. The deployment apparatus 300 may comprise any other suitable data logging tools, data processing means, sensors, visual or audible display, user interaction means or the like in order to allow complete control and/or positioning of the deployment arm 324, launch tube 340, anchor arrangement 326, high strength connection 328 and stent 301. The deployment arrangement 300 may comprise mechanical, electrical, electro-mechanical, pneumatic or hydraulic actuation means suitable for controlling the deployment arm 324, launch tube 340, anchor arrangement 326, high strength connection 328 and/or stent 301.

The conduit C is shown in Figure 11 to be disposed below the surface of the ground G. However, it will be understood that the conduit could be above ground, underwater or the like. In such embodiments, the deployment apparatus 300, fill tubes 306, 308, deployment arm 324, launch tube 340, anchor arrangement 326, high strength connection means 328 and stent 301 may be similar or identical, and work in an identical or similar manner regardless of the geographical location or position of the stent 301, or conduit C. Advantageously, the deployment of the stent 301 into the conduit C using the deployment arm 324 in this manner permits the deployment of the stent 301 into the conduit C while the conduit C contains a flow of fluid F, i.e. when the conduit C is live.

Provided that a fluid seal is provided at the access to the conduit C via a suitable access port 322, the insertion of the stent 301 into the conduit C can be performed without the need to evacuate or empty the conduit C. Alternatively, if the conduit C is empty and does not contain a fluid F, there may be no requirement for a fluid seal at the access port 322.

Once the stent 301 has been deployed by the deployment arrangement into a working position in the conduit, the evacuation arrangement will apply a negative pressure to one or more of the packing medium chambers containing the packing medium. In some embodiments, the packing medium may be provided in the packing medium chambers prior to deployment of the stent in the conduit and in other embodiments, the packing medium may be provided in the packing medium chambers after deployment of the stent in the conduit and before evacuation to compact the packing medium and make the stent rigid.

In some embodiments, no access port may be used and instead the stent may be deployed through an end of the conduit.

Figure 12 shows general steps of a method 400 of deploying a stent into a conduit, in accordance with embodiments of the invention. The stent comprises at least one chamber containing a packing medium when in use and the stent is configurable between a first configuration in which the packing medium in the chamber has a first packing density; and a second configuration in which the packing medium in the chamber has a second packing density, the second packing density being greater than the first packing density. The method 400 comprises a first step 402 of arranging the stent in the first configuration, when relative flexibility is required; and a second step 404 of applying a negative pressure to one or more of the at least one chambers containing the packing medium to reconfigure the stent into the second configuration, when relative rigidity is required.

Figures 13(a)-(c) show annular cross-sections of a stent 500 according to an embodiment of the invention, in three different configurations. In Figure 13(a) the stent 500 is shown with a series of longitudinal chambers positioned around the annulus containing air 502. Thus, the stent 500 is fully inflated in Figure 13(a). In Figure 13(b) the stent 500 is shown with alternate longitudinal chambers being filled with packing medium 504 before being evacuated. Thus, the stent 500 is partially inflated with air 502 and partially evacuated in Figure 13(b). This configuration may increase the rigidity of the stent 500, whilst also reducing the diameter of the stent 500 when compared to Figure 13(a) as shown (although this may not always be the case). In Figure 13(c) the stent 500 is shown with all longitudinal chambers being filled with packing medium 504 before being evacuated. Thus, the stent 500 is fully evacuated in Figure 13(c) to provide a very rigid and compact stent 500.

Figure 14 illustrates a control arrangement 508 for the stent 500 configured in accordance with Figure 13(c) for movement within a conduit 506. The conduit 506 is shown as transparent for ease of illustration. A negative pressure is applied to the stent 500 to evacuate each longitudinal chamber, which in this case is filled with packing medium 504. Due to the high packing density of the packing medium 504, the stent 500 is relatively rigid and has a reduced outer diameter. Accordingly, it is possible to manoeuvre the stent 500 along the conduit 506 with relative ease.

More generally, the control arrangement 508 may be configured to control the amount of inflation/evacuation and/or packing medium in each longitudinal chamber for selective control of the packing density, which in turn facilitates control of the relative rigidity and flexibility of the stent 500 as required.

It will be understood that various modifications may be made to the method and/or apparatus and/or device without departing from the scope of the invention as defined in the claims.

Claims

CLAIMS: 1. A method of deploying a stent into a conduit, the stent comprising at least one chamber containing a packing medium when in use and the stent being configurable between a first configuration in which the packing medium in the chamber has a first packing density; and a second configuration in which the packing medium in the chamber has a second packing density, the second packing density being greater than the first packing density, the method comprising the steps of; arranging the stent in the first configuration, when relative flexibility is required; and applying a negative pressure differential to one or more of the at least one chamber containing the packing medium to reconfigure the stent into the second configuration, when relative rigidity is required.
The method of claim 1, wherein the stent comprises at least one lumen and the method further comprises the step of; inflating one or more of the at least one lumen with a fluid.
3. The method of any preceding claim, wherein the stent comprises a plurality of chambers containing the packing medium and the method comprises inflating one or more of the plurality of chambers.
4. The method of any preceding claim further comprising the step of inserting the packing medium into the at least one chamber.
5. The method of claim 4, comprising providing the packing medium in the at least one chamber prior to introducing and/or manoeuvring the stent in the conduit.
6. The method of any preceding claim further comprising the step of positioning the stent into a working position within the conduit.
7. The method of any preceding claim further comprising the step of using a deployment arrangement to manoeuvre the stent in the conduit. 8. 9. 10. 12. 13. 14. 15.The method of claim 7, further comprising the step of removing the deployment arrangement from the conduit, leaving the stent in situ within the conduit.The method of any of claims 1 to 7, further comprising the step of removing the stent from the conduit.The method of any preceding claim, wherein the negative pressure differential is applied to the at least one chamber by an ambient pressure of the conduit.The method of any one of claims 1 to 9, wherein the negative pressure differential is applied to the at least one chamber by a vacuum pump.An apparatus for inserting a stent into a conduit, the stent comprising at least one chamber containing a packing medium when in use and the stent being configurable between a first configuration in which the packing medium in the chamber has a first packing density; and a second configuration in which the packing medium in the chamber has a second packing density, the second packing density being greater than the first packing density, the apparatus comprising; a deployment arrangement, the deployment arrangement configured to deploy the stent into a working position in the conduit; and an evacuation arrangement for applying a negative pressure differential to one or more of the at least one chamber containing the packing medium.The apparatus of claim 12, further comprising a packing medium insertion arrangement for inserting the packing medium into one or more of the at least one chamber of the stent.The apparatus of claim 12 or 13, wherein the deployment arrangement comprises a telescopic arm or umbilical configured to be extended to reach the working position of the conduit to deploy the stent, and wherein the evacuation arrangement is disposed in or on the telescopic arm or umbilical.The apparatus of any one of claims 12 to 14, wherein the evacuation arrangement comprises a vacuum pump. 16. 17. 18. 19. 20. 21. 22. 23.The apparatus of claim 13, wherein the packing medium insertion arrangement comprises a fill tube configured for transport of the packing medium to at least one chamber of the stent.A stent comprising at least one chamber for containment of a packing medium; and wherein the stent is configurable between a first configuration in which the packing medium in the chamber has a first packing density and a second configuration in which the packing medium in the chamber has a second packing density; and wherein in the second packing density is greater than the first packing density.The stent of claim 17, wherein the at least one chamber comprises a valve, and wherein, the valve is suitable for the application of a negative pressure differential for the reconfiguration of the stent from the first configuration to the second configuration.The stent of any of claims 17 to 18, comprising one or more inlets suitable for insertion of the packing medium.The stent of any of claims 17 to 19, wherein in the first configuration, the stent is flexible, allowing the stent to conform to a profile of a conduit; and in the second configuration, the stent is rigid.The stent of any of claims 17 to 20, comprising the packing medium.The stent of any one of claims 17 to 21, wherein the packing medium comprises one or more of powder, grains, rice, pellets, granules or particles.The stent of any one of claims 17 to 22, comprising a plurality of chambers and wherein one or more of the plurality of chambers is inflatable with a fluid when in use 24. The stent of any of claims 17 to 23 wherein the stent has a length, and wherein the at least one chamber containing the packing medium occupies a length substantially equal to the length of the stent or the at least one chamber containing the packing medium occupies a length less than the length of the stent.25. The stent of any of claims 17 to 24, comprising one or more of: a) a first end, a second end, and one or more fluid pathways connecting the at least one chamber to the first and second ends of the stent; b) a manifold connected to the at least one chamber; c) a packing medium outlet configured for removal of at least a portion of the packing medium; d) a fluid outlet configured for removal of at least a portion of a fluid; e) a stopper configured for selective blocking of a flow path through the stent when the stopper is packed with the packing medium. 15