GB2338195A

GB2338195A - A fluid treatment device

Info

Publication number: GB2338195A
Application number: GB9911215A
Authority: GB
Inventors: Andrew James Lee
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 1998-06-09
Filing date: 1999-05-17
Publication date: 1999-12-15
Anticipated expiration: 2019-05-17
Also published as: GB2338195B; GB9911215D0

Abstract

A fluid treatment device comprises a housing (1, fig 1) and a fluid treatment element, eg a filter 2, located in the housing to treat fluid flowing through the housing. The housing has an inlet and an outlet port and is of elongate shape divided along its length into two parts, 10, 11, each part having a set of triangular tooth formations 16 extending along opposite sides that mate with one another. The fluid treatment element is pleated across its width in a zigzag fashion with the sides of the fluid treatment element following the profile of the teeth formations on the housing. Opposite edges of the fluid treatment element are supported and sealed between the teeth formation of the two parts of the housing such that fluid flowing between the two ports is confined to flow through the fluid treatment element. The housing may be moulded of two identical parts from a flexible plastics material, such as PVC, and may be corrugated on the outer surface to improve flexibility. One of the parts of the housing may include a carbon dioxide sampling port. The device may be used as a catheter mount for medical respiration systems with a patient end fitting (3, fig 1) and a machine end fitting (4, fig 1). Suitable filter elements may be of any conventional filter material, such as a HEPA bacterial/viral filter. In the case of delicate filter elements, a ladder shaped support frame made from a thermoplastics material, eg acetate, may be used (see fig 6). Alternatively the fluid treatment device may be used for humidifying air flowing to or from a patient, in which case the fluid treatment element may be an HME (heat and moisture exchange) element. The device may be used to treat liquids as well as gases.

Description

2338195 1 FLUID-TREATMENT DEVICES This invention relates to

fluid-treatment devices.

The invention is more particularly concerned wl'th medical devices for filtering, humidifying or otherwise treating fluid, such as air, flowing to or from a patient.

In one particular application of medical respiration systems, a filter or HME device is connected at the machine end of a tracheal tube and connection to the device is made by a socalled catheter mount, that is, a relatively large bore, corrugated, flexible tube. The catheter mount provides a flexible interconnection between the tracheal tube and ventilator tubing connected at the other end of the catheter mount. One problem, with filters in particular, is that high efficiency filters tend to have a high resistance to flow unless they have a large surface area, in which case they tend to be bulky and heavy. It is also a disadvantage to have several different components interconnected in a breathing circuit because it makes rapid assembly more difficult, it increases the deadspace within the circuit and it increases the risk of accidental detachment of components. Proposals have been made to overcome some of the problems of previous arrangements, as described in GB2321604 and GB2169522. Previously proposed arrangements, however, suffer from various problems, such as difficulties in making the filter element or of sealing it in a housing.

It is an object of the present invention to provide an improved fluidtreatment device.

2 According to one aspect of the present invention there is provided a fluid-treatment device comprising a housing and a fluid-treatment element located in the housing to treat fluid flowing through the housing, the housing having an inlet and outlet port and being of elongate shape divided along its length into two parts, each part having a set of triangular tooth formations extending along opposite sides that mate with one another, the fluidtreatment element being pleated across its width in a zigzag fashion with the sides of the fluid-treatment element following the profile of the teeth formations on the housing, and opposite edges of the fluid-treatment element being supported and sealed between the teeth formation of the two parts of the housing such that fluid flowing between the two ports is confined to flow through the fluid-treatment element.

The housing is preferably flexible and corrugated. The two parts of the housing may be substantially identical. The fluid-treatment element is preferably a gas-treatment element such as an HME element or a filter. One of the parts of the housing preferably has a patient end fitting for connection to a tracheal tube connector, the other of the parts having a machine end fitting for connection to a ventilation tube connector. The two parts of the housing may be sealed with the fluid-treatment element by means of an adhesive or solvent along opposite edges of the fluidtreatment element. The fluid-treatment element may be supported by a ladder-shape support frame. The support frame may be of a thermoplastic material and the two parts of the housing may be sealed with the fluidtreatment element by causing material of the support frame to flow into sealing contact with both the fluid-treatment element and the two parts of the housing.

3 According to another aspect of the present invention there is provided an assembly including a fluid-treatment device according to the above one aspect of the invention, a tracheal tube, a connector connected between the tracheal tube and one end of the fluidtreatment device, ventilation tubing, and a connector connected between the ventilation tubing and the other end of the fluid-treatment device.

A catheter mount incorporating a filter, according to the present invention, will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of the catheter mount; Figure 2 is a simplified cross section side elevation view illustrating gas flow through the device; Figure 3 is an exploded perspective view of a part of the device; Figure 4 is a perspective view of one part of the catheter mount housing; Figure 5 is a cross-sectional side elevation view of one end of the mount; and Figure 6 is a perspective view of a part of a modified form of filter element.

The catheter mount comprises a housing 1 containing a fluid-treatment element in the form of a filter 2 and having a patient end fitting 3 at one end and a machine end fitting 4 at I,- 4 the opposite end. In use, the patient end fitting 3 is connected to a standard connector in the machine end of a tracheal tube and the machine end fitting-4 is connected to a standard connector, such as a Y-picce connector at the end of ventilation tubing extending to ventilation equipment. Gas flows along the catheter mount alternately in opposite directions during the inspiration and exhalation phases respectively, and flows through the thickness of the filter element 2.

The housing 1 is moulded in two, identical parts 10 and 11 of a flexible plastics material, such as PVC, although these parts could be of different shapes, such as if one were to include a carbon dioxide sampling port. The two parts 10 and 11 form the upper and lower halves of the housing 1, which is essentially divided in half along its length with each part including a respective one of the end fittings 3 or 4. Each part 10 and 11 includes a rounded, convex upper or lower wall 12, which is formed with lateral corrugations 13 so as to make it more flexible in a plane normal to the wall. Each part 10 and 11 also includes a side wall 14 and 15 extending longitudinally on each side. Each side wall 14 and 15 is corrugated slightly on the outer surface of the housing to improve flexibility and is profiled along its edge with a series of triangular teeth 16. The teeth 16 on the two parts 10 and 11 are shaped to engage with one another. The end of the part 10 and 11 with the end fitting 3 or 4 is formed with a radially-extending flange 17, the opposite end 18 of the part being shaped to mate with the flange on the other part.

The filter element 2 may be of any conventional filter material, such as a HEPA bacterial/viral filter of the kind used in the HEPA filter sold by SIMS Portex Limited of Hythe, Kent, England. The filter element 2 comprises a rectangular strip of material folded- backwards and forwards in a zigzag fashion across its width into a number of inclined pleats 20 of V-shape, equal to the number of teeth 16 on the housing 1 and having a length equal to that of the sides of the teeth. The width of the filter element 2 is equal to that of the housing 1 so that the pleated element can be located with its opposite edges 21 supported on the teeth 16 along opposite sides of the housing. The edges 21 of the filter element 2 are sandwiched between the teeth 16 on the two parts 10 and 11 of the housing, with the lateral edges 22 of the pleats 20 at opposite ends (Figure 5) being sandwiched between the flange 17 of one part of the housing and the opposite end 18 of the other part. Both longitudinal edges 21 and lateral edges 22 are sealed in a gas-tight fashion between the two parts 10 and 11 of the housing 1. This may be done in various ways. For example, a bead of an adhesive or solvent may be applied along the two parts 10 and 11 of housing 1 where they contact the filter element 2. Alternatively, heat may be used to cause material of the housing 1 or of the filter element 2 to flow forming a seal with the contacting component.

If a delicate filter element is used, it may be necessary to protect it from damage caused by flexing of the element, either during use or during the pleating process. This may be done, in the manner shown in Figure 6, by bonding the filter element 2' to a ladder-shape support frame 30, such as of an acetate material. The support frame 30 comprises two, narrow longitudinal strips 331 extending along the longitudinal edges of the filter element 2' and a number of lateral strips or rungs 32, one at each fold of the filter element. Each of the lateral strips 32 has a fold crease 33 to define the line of bend of the element. The space between adjacent lateral strips and longitudinal strips 32 and 3 1, forms a window 34 occupying most of the area of each pleat of the filter element. The longitudinal strips 31 of the support frame 3 0 are bonded between the teeth 16 of the two parts 10 and 11 of the housing 1, with the- - - 6 endmost lateral strips J32 being bonded between the flange 17 of one part and the end 18 of the other part. The support frame 30 is preferably of a thermoplastic material so that it can be bonded by heat both to the filter element and to the housing Flow of gas through the catheter mount is illustrated most clearly in Figure 2. Gas entering the right-hand, machine port 4 flows along the lower part 11 of the housing 1, entering the upper part 10 only by flowing through the thickness of the filter element 2. Gas can flow in the same way through the catheter mount in the opposite direction. The catheter mount thereby serves a dual purpose of providing a flexible coupling between the tracheal tube and ventilation tubing, whilst also acting as a low resistance, high efficiency filter without any increase in the size of a conventional catheter mount. The invention also avoids the need for a separate component with the attendant disadvantages this brings, of increasing time and complexity of assembly, increasing deadspace, increased risk of accidental disconnection, increased risk of accidental omission of the filter and increased contaminated waste products for disposal after use.

The device of the present invention need not be a filter but could be. some other form of fluid-treatment device, such as a heat and moisture exchanger employing a conventional HME element in place of the filter element. The device need not be used to treat gases but could be used to treat liquids.

1 7

Claims

A fluid-treatment device comprising a housing and a fluid-treatment element located in the housing to treat fluid flowing through the housing, wherein the housing has an inlet and outlet port and is of elongate shape divided along its length into two parts, wherein each part has a set of triangular tooth formations extending along opposite sides that mate with one another, wherein the fluid-treatment element is pleated across its width in a zigzag fashion with the sides of the fluid- treatment element following the profile of the teeth formations on the housing, and wherein opposite edges of the fluid-treatment element are supported and sealed between the teeth formation of the two parts of the housing such that fluid flowing between the two ports is confined to flow through the fluid-treatment element.

A fluid-treatment device according to Claim 1, wherein the housing is flexible.

3. A fluid-treatment device according to Claim 1 or 2, wherein the housing is corrugated.

A fluid-treatment device according to any one of the preceding claims, wherein the two parts of the housing are substantially identical.

5. A fluid-treatment device according to any one of the preceding claims, wherein the fluid-treatment element is a gas-treatment element.

i 6. A fluid-treatment device according to Claim 5, wherein the fluidtreatment element is an HME element.

A fluid-treatment device according to any one of the preceding claims, wherein the fluid-treatment element is a filter.

8.

A fluid-treatment device according to any one of Claims 5 to 7, wherein one of said parts of the housing has a patient end fitting for connection to a tracheal tube connector.

9.

A fluid-treatment device according to Claim 8, wherein the other of said parts has a machine end fitting for connection to a ventilation tube connector.

c 10. A fluid-treatment device according to any one of the preceding claims, wherein the two parts of the housing are sealed with the fluid-treatment element by means of an adhesive or solvent along opposite edges of the fluid- treatment element.

A fluid-treatment device according to any one of the preceding claims, wherein the fluid-treatment element is supported by a ladder-shape support frame.

A fluid-treatment device according to Claim 11, wherein the support frame is of a thermoplastic material and the two parts of the housing are scaled with the fluidtreatment element by causing material of the support frame to flow into sealing contact with both the fluid-treatment element and the two parts of the housing.

9 13. A filter substantially as hereinbefore described with reference to F accompanying drawings.

gures 1 to 5 of the 14. A filter substantially as hereinbefore describedwith reference to Figures 1 to 5 as modified by Figure 6 of the accompanying drawings.

15. An assembly including a fluid-treatment device according to any one of Claims 5 to 7, a tracheal tube, a connector connected between the tracheal tube and one end of the fluid-treatment device, ventilation tubing, and a connector connected between the vHation tub"na and the other end of the fluid-treatment device.

enti 1 t> 16. Any novel and inventive feature or combination of features as hereinbefore described.