Field of Invention

The present application is in the field of respirators. Specifically said respirators may be used in settings such as clinical settings such as hospitals, to protect the user from airborne hazards such as pathogens. This application in particular concerns the method of manufacturing a hood for a respirator, and for assembling the respirator from its component parts.

Background

Personal protective equipment is used in environments in which there are hazards to humans. The personal protective equipment allows a user to move through said environment whilst minimising the risks posed by said hazards. Examples of such environments include hospitals and clinical settings where there are likely to be airborne pathogens. For example, the air in wards containing covid-19 positive patients will likely contain particulates such as aerosols carrying the Covid-19 virus - and thus putting the staff in the ward at risk.

There have been many attempts to develop sufficient personal protective equipment to reduce the risk of the user effectively. However, these solutions either insufficiently alleviate the problem, or produce other problems. For example, many such devices are difficult to wear, heavy, bulky, or make the user's task more difficult. For example, face masks are often used by clinicians but these can be noisy if they are powered devices, or ineffective if they are not. Clinicians often have to speak with the patient and so the noise of the personal protective device can hinder this communication. Therefore, there is a need to provide an effective piece of personal protective equipment that does not induce other problems to the user. In particular, there is a need for a device to be worn on the user's head in order to reduce the risk on breathing in contaminated air containing pathogens or other hazards.

There is also a need to make it easy to remove the device, and to be able to do so without contamination. It may be beneficial for any non-disposable elements to be readily cleanable, and for the device to not be overly bulky.

There is a particular need for the method of manufacturing the hood, and assembling the respirator to be efficient in order to achieve the technical specification for the respirator, whilst lowering cost and time of delivery. In situations such as evolving pandemics quick delivery of stock may be highly advantageous. Summary of Invention

Aspects of the invention are set out in the independent claims. Optional features are set out in the dependent claims.

In accordance with a first aspect there is provided a method of manufacturing a hood for a respirator, the method comprising the steps of: selecting a first piece of material with a first thickness; selecting a second piece of material with a second thickness, wherein the second thickness is greater than the first thickness; cutting the first piece of material to a first predetermined shape, and cutting at least one valve opening in the first piece of material; cutting the second material to a second predetermined shape; welding the first material to the second material to form a flat template; positioning the valve within the valve opening; forming a central seam along the first piece of material such that the first piece of material forms a first hemisphere and a second hemisphere either side of said seam; folding the first material such that the hood is flat. This may be advantageous for several reasons. Firstly, the difference in thicknesses may reduce flex in the second material such that a visor portions may have less flex and thus create less visual distortions. Whilst a thinner fist material of the hood body may allow ore flex to aide with user movement. Moreover, folding the first material such that the resulting hood is flat means that the folds are contained within the second material and no join, fold or flex is created in the visor during packaging/transit - which in turn decreases visual distortions for the user - which is highly advantageous in clinical settings - such as during surgery.

Optionally, cutting the first material comprises cutting a stack of pieces of first material in parallel such that multiple pieces of first material in the first predetermined shape are formed. This may advantageously speed up the method, therefore reducing the cost of manufacture per unit.

Optionally, cutting the second material comprises cutting a stack of pieces of second material in parallel such that multiple pieces of second material in the second predetermined shape are formed. This may advantageously speed up the method, therefore reducing the cost of manufacture per unit.

Optionally, cutting the first piece of material additionally comprises stamping side holes in the base portion of the first piece of material. This may be particularly advantageous for increasing efficiency. This allows straps to be tied to the body of the hood, and allows this function without requiring an entirely new method step (such as welding an additional piece to the hood). Stamping can simply be part of the cutting - and therefore may go through multiple sheets at one time. This can help improve the efficiency of manufacture.

Optionally, wherein the valve is a two-part valve that comprises a first part and a second part, and that are connectable by a mechanical connection between the two parts. This may simplify the design of the hood.

Optionally, wherein the valve opening is smaller than the diameter of the valve so that force must be applied to fit the valve through the valve opening. This may be particularly advantageous as fitting an oversized valve through an undersized hole means that the fitting between the hole and valve is very tight. This may aid in alleviating any need for adhesive between the valve and the hood - making the process of manufacture more simple, efficient and less costly. The hole may for example be undersized by up to 1cm in diameter, but more preferably 0.2cm in diameter, or even 0.1mm in diameter.

Optionally, positioning the valve within the valve opening comprises positioning the first part through the valve opening and mechanically connecting the first part and second part of the valve together. This may offer a simple way of connecting the valve.

Optionally, wherein in connecting the first and second parts of the valve together the first piece of material is additionally joined to the valve by the mechanical connection. This may be particularly advantageous as it may help form a strong bond between the valve and the hood, and stop any air exiting from the hole without exiting via the valve. This bond therefore may be able to be made without adhesive, which is highly advantageous for increasing efficiency of manufacture.

Optionally, folding the first piece of material comprises not folding the second piece of material. This may advantageously keep the visor completely flat at all times to reduce any visual distortions for the user. Optionally, wherein welding the first piece of material and the second piece of material together comprises RF welding the first piece of material and the second piece of material together.

Optionally, after welding the first piece of material and the second piece of material are flush together. This may advantageously reduce any brow or ridge between the visor and the hood body, and so reduce any visual distortions in the visor.

Optionally, forming a central seam comprises clamping the material of the first piece of material together to form a ridge and fusing the ridge to form a central seam. This may advantageously create the shape of the hood. In some embodiments the proximal and distal sides of the flat template are clamped and fused in this way to create the central seam. The central seam offers structure to ensure the flex in the hood is in the hood body either side of the visor, and not in the visor itself to limit visual distortions.

Optionally, the clamping comprises bar clamping either side of the ridge. This may be an efficient method of producing the central seam.

Optionally, the first piece of material is formed from PVC. This may offer both cost benefits, ease of manufacture and aid with recyclability.

Optionally, the second piece of material is formed form PVC. This may offer both cost benefits, ease of manufacture and aid with recyclability. The recyclability is greatly increased when both the first and second materials are made from PVC.

Optionally, the first piece of material has a thickness of 150 microns. This may aid the flexibility of the hood body.

Optionally, the second piece of material has a thickness of 500 microns. This may help to limit flex in the visor, whilst not restricting user movement overly.

Optionally, the first piece of material forms a hood body.

Optionally, the second piece of material forms a visor.

Optionally, the method further comprising forming elongate straps that are connectable to the hood. In some embodiments these may be elongate strips, and in some embodiments may provide a slit in each strap such that the straps may be connected to on another. The straps may advantageously interact with the side holes. Optionally, cutting comprises removing an aperture for use as an air inlet. In some embodiments a thicker ring may be added to the periphery of this aperture to prevent fraying or other damage during use.

Optionally, the method further comprising adding a score line between the aperture and the base of the hood, wherein the score line comprises perforations linked with material there between to form a tearable seam. This may advantageously allow a user to remove the hood quickly and whilst minimising contact between the outside of the hood and the user, in order to minimise the risk of contamination.

In accordance with a second aspect there is provided a hood for use in a respirator manufactured using the method of the first aspect as set out above.

In accordance with a third aspect there is provided a method of assembling a respirator, the respirator comprising a hood, a collar comprising a top portion and a bottom portion, an impeller, and a cable for connecting the impeller to a power source, the method comprising: placing the impeller in a void contained in either the top portion or the bottom portion of the collar; placing a double adhesive sided gasket onto the portion of the collar containing the impeller; connecting the cable to the impeller through the portion of the collar; placing the second portion of the collar onto the other side of the double sided adhesive gasket; attaching the hood to the collar. This may advantageously allow a respirator to be assembled from the component parts quickly and easily and the double sided gasket may also improve the respirator as there may be less excess adhesive.

Optionally, attaching hood to collar comprises attaching three connector portions on the hood to three protuberances on the front of the collar. This may connect the hood and the collar together effectively, and reduce flex in the visor portion.

Optionally, the double sided adhesive gasket is formed from 3M tape.

Optionally, the gasket is coated in an adhesive on both sides.

Optionally, wherein the adhesive is acrylate. Optionally, the adhesive layer is 0.05mm to 0.1mm thick, preferably wherein the adhesive is 0.076mm thick. This thickness has been found to be beneficial as it may provide sufficient structural support, whilst minimising excess adhesive.

Optionally, connecting the cable through the portion of the collar comprises feeding the cable through a hole in the collar and around a U-bend shaped channel to the void in which the impeller is housed. This may prevent unwanted decoupling of the cable from the impeller and/or power source so that the device remains in use at all desired times.

Brief Description of Figures

Figure 1 is a flow chart showing an exemplary method for manufacturing the hood of the respirator - this flow chart includes some optional steps.

Figure 2 is a flow chart showing an exemplary method for assembling a respirator from its constituent parts.

Figure 3 shows a flat template for a hood, wherein the hood is in accordance with a first embodiment.

Figure 4 shows a template for a visor (the second piece of material) in accordance with a first embodiment.

Figure 5 shows a flat template for a hood, wherein the hood is in accordance with a second embodiment.

Figure 6 shows a template for a visor (the second piece of material) in accordance with a second embodiment.

Detailed Description of Figures

Figure l is a flow chart showing an exemplary method for manufacturing the hood of the respirator - this flow chart includes some optional steps.

The first step shown is material preparation. This may include the manufacture of the material from which the hood may be made. In this case this may be PVC, with the hood body made from PVC that is 150 microns thick and this visor portion made from PVC that is 500 microns thick. However, this step may be performed by a third party and this material may simply be purchased. This step is therefore not essential to the claimed method. The next step comprises cutting the material to the correct shape/size. Multiple sheets of the material may be placed on top of each other. The cuts may then be made. These cuts may be made in any suitable way. For example, a sharp metal stamp in the correct shape may be formed and quickly pressed through the material. This may form the shape of the hood body. A similar process may be used for the creation of the visor.

The cutting of the hood body may further comprise the removal of material to form apertures or holes. For example, a semicircle may be removed either side of the hood body. When these two sides are mated these semicircles may join to form a circular aperture for the air inlet. A stamp may also be used to stamp the skirt portion of the hood body (the portion below the visor) to create strap holes for accepting a strap through. The strap may then be used by the user to manage the movement of the skirt portion during use. A valve hole will also be stamped into the hood body.

It is noted that the cutting step may further comprise forming a score line. The score line may be positioned on either (or both) of the extreme right or left hand sides of the hood body. In particular, the score line may be situated below the semicircle to form the aperture for the air inlet, and may extend to the base of the skirt portion of the hood body (the base of the hood body itself). This score line may be used by the user to tear the score line in order for ease of removal of the hood after use.

The next steps comprise inspection and scrappage. These are optional steps. The cut material may be checked for anomalies. Any anomalies will then be scrapped (and ideally recycled).

The next step comprises window welding. This comprises welding the visor portion to the hood body. This may be along the four sides of the visor portion such that the visor portion sits within the hood body. The welding may be performed by RF welding, although any suitable attachment may be used. It is advantageous for the join between the hood body and the visor to be flush, as this may aid with minimising visual distortions as the hood is then more likely to be arranged vertically upright relative to the user's face in use. Once the visor is joined to the hood body a flat template for the hood is formed.

Following this the valve may be assembled. Any suitable valve may be used and may be attached to the hood at the valve hole by any suitable means. In a particularly advantageous embodiment the valve may comprise a two-piece valve. A first piece may be placed into the valve hole. It is noted that the hole may be undersized (by for example 1mm) so that the fit between the valve and the hole is flush. The second portion of the valve may then be attached to the first portion of the valve. Preferably a flange of hood material will be contained within the mechanical connection between the two valve portions. This may then bind the valve together with the hood without the use of any adhesive. This method is therefore both time and cost effective.

The next step is entirely optional. The visor may be trimmed to a predetermined shape/size as/if required.

The next step is labelled forming welding. This comprises taking the right and left most peripheral portions of the hood body and bringing them together. These extremities are then fused together to form a central seam. This then creates a three- dimensional hood that may encapsulate a user's head. The central seam may be formed by bringing the material together and clamping it with a bar element. The two clamped portions may then be fused together by welding or the like (for example a textile ligature may be used for this attachment). The clamping of the material however results in the central seam forming a ridge along its longitudinal extent. This ridge may be advantageous in that it may help maintain the hoods general shape during use, and minimise contact between the user's head the hood during use.

It is noted that forming the central seam also forms the aperture for the air inlet at the rear of the hood as the two semicircles are brought together by this process.

The next step is entirely optional and comprises trimming the seam to remove any anomalous portions (that for example are thicker and so not visually appealing).

A reinforced ring may then in some embodiments be welded to the aperture for the air inlet. This may be a ring that surrounds the circumference of the aperture. This reinforcement may comprise thicker material of the same material. For example, the reinforcement ring may be 500 micron thick PVC. This may prevent the aperture from being a point of weakness in the hood.

An IPQC check may then be performed to ensure the hood meets required standards. Any hoods not meeting this standard may be scrapped.

A tie or strap may be formed. This may be an elongate piece of PVC. This may be stamped to create an aperture, such as a zig zag aperture so that multiple ties can be attached together.

The next stage comprises folding the hood. The hoods are delivered flat so multiple hoods can be sent in a single box. However, any folding of the visor may be detrimental as it may cause permanent folds to appear in the visor and these folds may cause visual deformation to the user which may prohibit them from performing certain tasks such as surgery. Therefore, the folding of the product is performed on the hood body around the visor. The hood is folded to make a flat element suitable for shipping but only the hood body is folded and the visor portion is not folded in any way.

The next phase is optional and comprises putting the hood in a bag. The next stage is also optional and comprises heat sealing the bag. As the hood may be formed in a sterile environment this may ensure that the hood remains sterile prior to use. This may then be loaded into the box and the box sealed. A second check may be performed and any items not conforming to standards may be scrapped. The box then may be stored or shipped.

Figure 2 is a flow chart showing an exemplary method for assembling a respirator from its constituent parts. The constituent parts of the respirator comprise a top portion and a bottom portion of the collar body. An impeller that is configured to sit within a void within the collar body, and an air filter that is configured to be attached to the impeller - so as to feed filtered air to the impeller. Air output by the impeller flows into an air pathway within the collar body and within this air pathway is configured to sit an indicator to indicate if the flow level is at a sufficient level. A hood is configured to be attached to the collar body.

The first step in the flow diagram is placing the impeller in a void contained in either the top portion or the bottom portion of the collar. The position of the impeller within the collar body must be correct, and therefore the void may contain various alignment lips, or collars used to align the corresponding portions of the impeller (such as the first air inlet, the outer shell and the motor portion). Placing the impeller in the void may comprise aligning the impeller accurately using the alignment lips present within the collar body.

It is noted that the impeller may be placed in either the top or the bottom portion of the collar body. The assembly is ambivalent as to which portion of the collar body is used as the principal base in construction. This is advantageous as should an element of the respirator be developed further then this gives flexibility such that any development may lead to one portion of the collar body leading to ease of assembly.

The next step in the flow diagram comprises placing a double adhesive sided gasket onto the portion of the collar containing the impeller. In practice however the second and third stages may be swapped in order. The double sided gasket may be formed from a strong but flexible material. This material may for instance be 3M tape. This enables the gasket to be thin in depth, but still sufficiently strong for its application. Moreover, the gasket may be coated with adhesive on both sides. This enables the gasket to be adhered to both portions of the collar body to ensure connection between the portions. The adhesive may be any suitable adhesive, but it may be preferred for the adhesive to be acrylate. Gasket connection is preferred over the straight application of a layer of adhesive because the thickness of the adhesive coating on the gasket can be controlled and can be minimised. This means that when the two portions of the collar body are combined and pressed together the amount of excess adhesive is minimised. Excess adhesive can spread out of the join upon the application of pressure and can pick up detritus and make the collar harder to clean. Indeed, the preferred thickness of the adhesive layer is 0.05mm to 0.1mm in order to minimise the amount of excess adhesive whilst still forming a strong bond between the two portions of the collar body. In this particular embodiment the adhesive is 0.076mmm thick and this has been found to be particularly effective.

Both sides of the gasket may be covered with a protective covering to keep the adhesive fresh, and to prevent the gasket from sticking to surfaces until it is intended to do so. Therefore, placing the gasket onto the portion of the collar body containing the impeller may comprise removing one such covering from one side of the gasket and placing the uncovered side of the gasket onto the top of the portion of the collar body containing the impeller. The gasket and the portion of the collar body may then be bonded by the adhesive. Pressure may be applied to help form this bond between the collar body portion and the gasket. However, at this stage the other cover of the other side of the gasket may be retained so as to keep the adhesive on the other side fresh, and to ensure it does not interfere with other steps in the assembly process.

The next step in the assembly comprises connecting the cable to the impeller through the portion of the collar. The cable provides power to the impeller, and in particular to the motor within the impeller that drives the rotating component within the impeller. The cable is configured to pass through a hole through the portion of the collar body. Both portions may comprise said hole to enable assembly, or alternatively only one hole may be machines, in which case the portion with the hole may be the preferred portion to use as the base for assembly.

The cable is then inserted through the hole and into the void where the impeller is housed. The cable can then be connected to the impeller. After being inserted through the hole the cable may in some embodiments be inserted through a channel emanating from the hole, said channel being in a U-bend shape. The U-bend shape may prevent tension in the cable from being transferred to the connection point with the impeller, and thus may reduce the risk of the cable and the impeller decoupling during use. The fourth step comprises placing the second portion of the collar onto the other side of the double sided adhesive gasket. This may comprise removing the second cover for the second adhesive side of the gasket and then connection the other portion of the collar body to the adhesive of the gasket element. The collar body may then have pressure applied to ensure the connections are strong. If any excess adhesive is forced out of the side during such pressuring this excess adhesive may then be removed.

The final step then comprises attaching the hood to the collar. It is noted that this may be omitted from assembly, and may instead be performed by the user shortly before use. The hood may be attached to the collar by inserting the air filter through the aperture at the rear of the collar, and by attaching the connecting portions at the front of the hood to the connecting portions at the front of the collar. The connecting portions of the hood may fit around protuberances positioned on the front of the collar.

Figure 3 shows a flat template for a hood, wherein the hood is in accordance with a first embodiment. Figure 3 shows the that hood comprises two principal sections, the hood body and the visor portion.

This visor portion is approximately rectangular. The lower edge is curved so that in use (when the visor itself is curved) the lower edge forms a straight line. The connecting portions are shown on the left and right hand sides of the bottom of the visor portion.

The hood body comprises an aperture for the air inlet of the collar body (the two semicircles removed from the extreme right and left hand sides of the hood body). The hood is formed by coupling the extreme right and left hand sides together and forming a central seam along the join. This join then brings the semicircles together to form the aperture for the air inlet.

Also shown in this Figure is the hole for the valve. This is positioned on the top of the hood body, but is off centre so that the valve does not interfere with the central seam, as this may cause the hood to lose its shape during use.

Figure 4 shows a template for a visor (the second piece of material) in accordance with a first embodiment. This shows just the visor portion alone. The connectors are shown. These are the elongate holes near the bottom of the visor portion. Also shown are two strengthening rings that may be attached to these connectors to strengthen the connectors. Below the connectors are shown apron connectors. This comprises a tab with a spiral aperture. The apron straps (or other items of personal protective equipment) may be placed through the apertures to attach the respirator to the other elements of PPE for greater protection.

Figure 5 shows a template used in the manufacture of the hood. On the left hand side is a zoomed in view of the perforations showing that the perforations in the score line are 5.5mm long, and the gaps between the perforations are 3mm long. The perforations are therefore longer than the gap between the perforations. The perforations may be any length between 5mm and 6mm. The tear strength needed to tear these perforations varies between 15N and 30N dependent on the exact length of the perforations. It is noted that handles may be added to the hood body adjacent the score line and the perforations, such that the user may grip the handles in order to tear the score line in order to remove the device. This may make the removal of the hood easier for the user as the handles may be easier to grasp.

The template shows the visor portion and the hood portion. In this example the apron connectors are not shown. The central seam will be formed by connection the two sides of the hood body together to form an encapsulating hood. It is noted that the hood body and the visor portion may be made from the same material - e.g. PVC in order to make the hood more readily recyclable. In this example the visor portion is made of the same material - but is thicker (around 500 microns in thickness) in order to reduce the flex of the visor portion. The hood body on the other hand has a thickness of 150 microns - and so allows for greater user movement.

A valve hole is also shown either side of the template. The valve hole may be undersized such that it is smaller than the diameter of the valves - so that the seal formed from the valve entering the valve hole is tight. This may mean that no adhesive is required for the valve to be situated correctly. A two-part valve connecting together with the valve whole between the two portions of the valve may allow for such a tight connection.

The air inlet is shown as two hemispherical cut-outs at the periphery of either side of the template. The perforations may be formed adjacent the edge of either or both sides of the hood - below the hemispherical cut-out for the air inlet.

It is noted that this embodiment differs from the first embodiment in the shape of the template. The hood body comprises two portions with pronounced humps. These form a raised surface above the user's head that is curved (with approximately the same curve profile) during use. This may give the user may space within the hood, and minimise contact between the hood and the user's head during use.

Figure 6 shows a template for the visor portion. This shows the apron connectors and a curved top edge of the visor. This is so that when the visor is bent in use (as shown in Figure 1) the top edge becomes flat. Alternatively, the top edge may be flat or otherwise curved in the template and may be curved during use. This may however complicate the join between the visor and the hood body, which then maybe reinforced. The dimensions of the connectors in this embodiment are also shown - as are the approximate dimensions of the visor itself.