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 hood used to protect the user from the outside environment.

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 hood to be flexible and strong to enable the full range of user movement. There is also a need for the hood and collar together to not lead to misting, and for the shape of the hood to promote good air flow. It may be advantageous for the hood to be recyclable as it may be a single use item. It may also be advantageous for the hood to be easily removable. Summary of Invention

Aspects may be set out in the independent claims and optional features may be set out in the dependent claims.

In accordance with a first aspect there is provided a hood for a powered air purifying respirator, wherein the hood is configured to be attached to a collar element and in use inflated with to ensure fluids cannot enter the hood, the hood comprising: an aperture at the base of the hood through which a user's head fits; a hood body comprising a visor portion configured to provide the user a viewpoint, and first and second hemispheres, wherein the first and second hemispheres are joined by a seam situated along the centre of the device, and further wherein the seam is absent from the visor portion; a second aperture configured to house an air inlet; a valve outlet to outlet air from inside the hood to the external environment. This may be advantageous as the shape of the hood may allow for greater flex of the sides hemispheres, whilst minimising unnecessary flexing of the visor during use. This in turn may hen limit visual distortions created for the user. The central seam may also allow for a shape of hood to be created that is robust, and that minimises contact between the user and the hood in use, in order to improve the feel for the user, and lessen claustrophobic reactions to wearing the hood. The seam therefore helps make the hood be more ergonomic.

Optionally, the visor and the hood body are joined at the top of a visor by a join, and configured such that a brow is created. This may create space above the user's eye line that may increase the viewpoint for the user.

Optionally, the visor is angled such that it is at an acute angle with respect to the plane the collar is positioned within. This may improve the circulation of air within the hood.

Optionally, the hood further comprising a skirt portion below the visor portion and the hemispheric portions, wherein in use the skirt sits below the collar. The skirt may help stop air from entering the hood from below the collar, whilst it may also allow (in positive pressure use) for air to exit the hood via the collar and exiting below the skirt.

Optionally, the hood further comprising two or more straps, wherein the straps are configured to be tied around the skirt portion to limit the movement of the skirt portion. In accordance with a second aspect there may be provided a hood for a powered air purifying respirator, wherein the hood is configured to be attached to a collar element and in use inflated with positive pressure to ensure fluids cannot enter the hood, the hood comprising: an aperture at the base of the hood through which a user's head fits; a hood body comprising a visor portion configured to provide the user a viewpoint; a second aperture configured to house an air inlet; a first valve outlet to outlet air from inside the hood to the external environment; a skirt extending below the point that in use contacts the collar, such that in use the skirt extends below the collar; the skirt comprising a scored line configured to allow the scored line to be ripped by the user, to enable removal of the hood. This may advantageously allow a user to rip the scored line and then remove the hood whilst minimising contact between the user and the outside of the hood to therefore reduce the risk of contamination.

Optionally, the scored line positioned at the rear of the hood opposite the visor portion in line with the second aperture. This may provide a good place for the rip to begin - as it begins from an aperture already in place - and is therefore a point of weakness.

Optionally, the scored line extends from below the second aperture to the base of the skirt. This may allow for ease of removal.

Optionally, the force required to tear the seam is 15-30N. This may be a natural amount of force for a user to impart without being overly onerous, and whilst minimising unintentional tears.

Optionally, the in use the hood is inflated with positive pressure. This may reduce ingress of air from the environment into the hood.

Optionally, the second aperture is positioned at the rear of the hood, opposite the visor portion. This may reduce the noise experienced by a user from the device.

Optionally, the hood is made from a flexible material, optionally wherein said material is PVC. This may improve the recyclability of the device as it is made from one material, and as this material is widely recycled. Optionally, the first aperture is circular, such that the cross sectional base of the hood is circular.

In accordance with a third aspect there is provided an air purifying respirator comprising the hood of any preceding claim, and a collar, wherein the hood and the collar are configured to be attached.

Optionally, the respirator further comprises a filter positioned within the second aperture of the hood and attached to the collar.

Optionally, wherein the filter is attached to an impeller, wherein the impeller is attached to the collar, and wherein the impeller is configured to create air flow within the hood.

Optionally, an indicator is positioned within the collar and is configured to sense if airflow from the impeller drops below a predetermined level. This may improve safety by sensing if the device is not functioning as intended and acting as an indicator to indicate that the user should leave the hazardous area.

Brief Description of Figures

Figure 1 shows a collar from a front perspective.

Figure 2 shows a collar from above.

Figure 3 shows a front view of a model of air flow within the hood of the respirator when the hood is connected to the collar and is in use.

Figure 4 shows a side view of a model of air flow within the hood of the respirator when the hood is connected to the collar and is in use.

Figure 5 shows a perspective view of the collar from the rear.

Figure 6 shows a side view of the collar.

Figure 7 shows a plan view of the collar, with the collar rotated relative to Figure 2.

Figure 8 shows a cross sectional diagram of the collar.

Figure 9 shows an internal diagram of the inner features of the base section of the collar.

Figure 10 shows a rear perspective view of the hood and collar.

Figure 11 shows a front perspective view of the hood and collar. Figure 12 shows a line drawing of the hood.

Detailed Description of Figures

Figure 1 shows a collar from a front perspective. This shows a collar body that comprises a torus shape. Adjacent the front of the collar body (in this case on the right hand side) is an air outlet on the top surface of the collar body. This air outlet is offset from the centre of the collar body. Adjacent the air outlet is situated an indicator to indicate if the rate of air flow through the air outlet is above a predetermined level. At the rear of the collar body is an air inlet.

Although not shown, inside the air inlet is an air filter. The air filter then feeds the filtered air into an impeller also housed within the collar body. The impeller is housed within the bulge in the collar body at the rear of the collar body. The air output by the impeller then flows through an air pathway within the collar body, through the indicator and out of the air outlet.

Figure 1 also shows two protuberances on the right and left hand side of the collar, around the centre of the collar body and offset from the centre of the front of the collar. These are connectors. These connectors are configured to connect to a corresponding element on the hood in order to connect the hood and the collar together.

The torus of the collar body may have a diameter of 32 mm (that is the cross section of the torus may have this diameter). The diameter of the collar as a whole is approximately head width (or just larger than head width) so the collar can comfortably fit over a human head). This diameter is therefore between 20 and 30cm on average.

Figure 2 shows a collar from above. This additionally shows that this indicator may show green if the air flow is above the predetermined level, and red if the air flow is below the predetermined level. The filter is shown more fully in Figure 2. Any suitable air filter may be used. For example, in a clinical setting a suitable air filter to remove pathogens from the air may be used.

Figure 3 shows a front view of a model of air flow within the hood of the respirator when the hood is connected to the collar and is in use. This shows the high velocity of air (around 7m/s) exiting the air outlet. This air then decelerating and slowing to around 4m/s and flowing in an approximately linear path diagonally toward the top left corner of the hood. Here the air slows further to around 3m/s. The linear air flow path goes to the left of the user's nose in order to reduce discomfort in the user. The offset of the air outlet from the centre of the collar body aids with this direction of air flow and allows the faster air flow (which users can find more uncomfortable) form being directed at a user's nose or mouth. There is limited air flow in front of the user's face with the majority of the air flow restricted to other areas the hood (albeit at a lower speed).

The fluid outlet is offset by an angle of 30 degrees from the front of the collar body. This angle is measured by rotation around the torus (taking the front to be 0 degrees, and the rear of the collar body to be 180 degrees). In other embodiments the air outlet may be positioned at any point between 20 and 40 degrees along the circumference of the torus of the collar body. It has been found that this angular range (and 30 degrees in particular) is favoured for creating air flow that avoids the user's key facial features (in particular the nose, eyes, ears and mouth).

Alternatively, the air outlet may be offset by a distance of approximately 30mm from the front of the collar body to achieve this same effect.

Figure 4 shows a side view of a model of air flow within the hood of the respirator when the hood is connected to the collar and is in use. This shows that a circulating system air flow is formed around the periphery of the inside of the hood. The air flow leaves the air outlet at a speed of around 7m/s on average. The air flow then goes up towards the top of the hood. When reaching the top of the hood it is travelling at approximately 4m/s. The air flow then continues along the top of the hood at around 2 m/s. The air flow then continues around the periphery of the hood, descending at the back of the hood, and then flowing around the base of the hood back towards the point at which the air outlet is situated. This then may recirculate the air. It is noted that a valve is situated at the top of the hood in the centre of the hood. Therefore, some of the air flow in every rotation through the air flow path exits the hood via the valve. If the seal between the collar and the hood is a positive pressure seal (it may in some embodiments form an airtight seal) then air may also escape from below the skirt of the hood.

Figure 5 shows a perspective view of the collar from the rear. This shows the filter element in more detail, and that a filter adaptor may be used. A filter adaptor may allow a filter to be replaced with a different type to allow the collar to be used with replacement filters even if the original filter type is not available.

Also shown in more detail are the wings or flanges of the collar element. These flanges protect the air filter (and to an extent the impeller) from any knocks or forces as a user collides into other objects. The flanges are shaped to be triangular (although this is not essential), and the vertices and edge of the flanges may be atraumatic in some embodiments.

For example, the flanges may protect the air inlet, filter and impeller should the user hit the back of the device on an object (such as a wall) during use. If the filter is exposed and takes the brunt of such a collision it may stop functioning as intended - and so the user may then be at risk of inhaling hazardous material from the environment, such as pathogens in clinical settings.

The flanges may protrude a distance of 30mm beyond the fluid inlet (e.g. the final surface of the air filter). This may be advantageous for providing the necessary protection without adversely affecting the weight distribution of the collar, or causing more collisions due to an overly long extension. Alternatively, the flanges may be any length from flush with the end of the air filter or longer.

The flanges are shown as being approximately triangular in shape. This may allow the flanges to provide strength, whilst minimising the space they take up and the weight they add to the device. Other shapes may be used such as trapeziums, or the like.

The flanges shown have atraumatic edges and vertices. This may reduce risk of injury should a user collide with another user. If the other use is wearing a hood, it may also reduce risk of hood perforation. This may be a serious risk in a cramped or crowded room such as a surgical theatre if all the clinicians are wearing these devices.

In some instances, the flanges may ensure a complete seal between the collar body and the hood. For example, if the hood extends to the periphery of the collar body (as shown in Figure 4) then a tighter seal may be developed between the collar and the hood due to the presence of the flanges. This seal may be an airtight seal, or a positive pressure seal (so that air can only leave the hood, but cannot enter the hood from anywhere other than the air inlet.

Figure 6 shows a side view of the collar. This shows a side view of the flanges. This also shows that the collar body is thinner in the central portion and is thicker at both the front and rear of the collar. A weighting element may be situated at the front of the collar. The weighting may provide a more ergonomic weight distribution so that the collar body is front heavy. This means that when a user bends for instance the rear of the collar is not raising the front of the collar body into the user's chin - and so improves the user experience.

The rear of the collar may be thicker because it houses the impeller within the collar body. This is housed in the void in the bulge at the rear of the collar. Any suitable impeller may be used. For example, an impeller may be used that has an airflow of approximately 1701 per minute, or that reduces noise to allow a user to communicate with others whilst using the hood.

Also shown in this Figure is a join between the top portion of the collar body and the bottom portion of the collar body. The elements may be joined by adhesive, such as through the use of a suitable glue. Both the top portion and bottom portion of the collar body house a portion of the void that is configured to hold the impeller.

Figure 7 shows a plan view of the collar, with the collar rotated relative to Figure 2. This shows the air inlet into the air filter.

Figure 8 shows a cross sectional diagram of the collar. This shows the air filter 20, the impeller 16 and the air flow pathway 14. The air flow pathway 14 is housed in both the top portion of the collar body, and the bottom portion of the collar body. This is the case throughout the air pathway. At no point is the air pathway fully encapsulated in one of the two portions. This makes the weight distribution more equal, and therefore is ergonomic to use.

The air flow path then passes through the indicator 1, and then out of the air outlet 12.

It is noted that the flanges are not shown in this cross section - but may be present in many embodiments.

Figure 9 shows an internal diagram of the inner features of the base section of the collar. This shows the weighting element situated at the front of the collar body. This is shown as being situated in the of bottom half of the collar body. This may give the collar body a lower centre of mass which may make it more stable. However, the weighting element may also be positioned in the top half of the collar body in other alternative embodiments.

This also shows holes for corresponding pins in the top half of the collar body to fit within to aid the bond between the two portions of the collar body.

The void for the impeller is shown. This feeds air directly into the air pathway which is also shown.

Where the air pathway passes through a void configured to house the indicator a collar portion is used to help with alignment of the indicator within the air pathway, to ensure that the collar is correctly assembled so that the indicator functions as intended. Any suitable indicator may be used such as an electronic air flow gauge. In one particular embodiment a mechanical indicator may be used in which a spring inverts if the air flow (and therefore the associated force) drops below a predetermined level.

Figure 10 shows a rear perspective view of the hood and collar. The collar is shown as described above with reference to the other drawings.

The hood shown comprises a visor portion (mostly not visible in this image -see Figure 11 below) and the body portion. The body portion is approximately cylindrical, with a curved rear side tapering towards the top of the hood. The rear of the hood comprises an aperture that is used as an air inlet. The air filter and air inlet of the collar fit within the air inlet of the hood when in use.

Also shown is a central seam. The central seam separates the right and left hand hemispheres of the hood body (these may be referred to as the first and second hemispheres). In manufacture this seam brings together the extremities of the flat template for the hood body, and so fuses the hood body into its shape. The central seam helps the hood keep this shape, even though the hood may be made from thin flexible material (which allow the user freedom of movement within the hood). As the central seam provides such structure it minimises the number of times the user's head contacts the inner surface of the hood. Such contact may not only be uncomfortable, but may also cause more fogging of the hood. Therefore, the reduction in this contact is beneficial for many reasons.

A valve is also shown at the top of the hood. The valve allows air within the hood to leave. The valve may be a one-way valve, or may simply function as a one-way valve due to the hood being filled with positive pressure (i.e. greater pressure than the surrounding environment) during use.

The valve is positioned off centre in this embodiment. This is advantageous as if the valve was positioned in the centre it would interrupt the central seam, and so would reduce the strength (and therefore the strength of the shape) of the hood.

The top of the hood also shows a brow join which is positioned perpendicular to the central seam. This brow join creates a brow above the brow of the user's head. This may keep the front of the hood from contacting the front of the user's face, and so reduce fogging of the visor, and contact between the visor and the user's face. This may also improve the rigidity of the shape of the hood.

The hood may be formed from PVC or any other suitable material. Figure 11 shows a front perspective view of the hood and collar. This shows the visor in more detail. The visor forms a wide angle viewing element around the user's face. The visor is transparent, whereas in this embodiment the hood body is translucent/opaque. At the top of the visor is a brow before the brow seam, which is attached to the central seam.

The visor comprises two connectors which are configured to connect to the connectors located on the front of the collar body. Attached to the connectors are apron connectors. These are tabs that extend from the connectors, and may be welded to the connectors/visor portion. The apron connectors comprise a spiral aperture that allows an apron strap (or other PPE strap) to enter the spiral aperture and to be trapped within the aperture. This connects the respirator (the hood and collar) to the apron or other PPE.

It is also noted that the hood comprises a skirt portion that extends below the visor portion. The skirt portion in use sits below the collar. As the hood is filled with positive pressure air can escape from below the skirt, but cannot enter the hood from the outside through the skirt opening.

Figure 11 also shows straps attached to the rear of the hood body. These straps may for example be welded to the hood body. These straps may be used to tie the skirt portion such that the skirt portion does not flap around, or otherwise interfere with the user's task or actions.

It is noted that whilst the visor is shown in Figure 11 as extending approximately vertically upwards in use (and indeed this is also shown in Figure 4) in other embodiments the visor may be arranged differently. For example, in some embodiments the visor may be slanted towards the user. The brow element may then be used particularly to limit contact between the top of the visor and the user's forehead. This slanted visor may reduce the amount of material required to form the hood. The slanted visor may also provide more structural rigidity to the hood overall so that it does not become deformed as simply though user movement. However, some user's find that there is still contact between the user and the slanted hood, so in some embodiments this can be a drawback.

Figure 12 shows a line drawing of the hood. This Figure additionally shows a score line. The score line extends (in this embodiment) from the aperture configured to house the air inlet to the base of the skirt. The score lines may be used for tearing. For example, a user may wish to remove the hood at the end of use. The hood may be disposable. The user when removing the hood faces a technical problem. They may want to reduce any contact between the outside of the hood, which may be contaminated, and any other surface such as their clothing, skin etc. To do this the user may therefore tear the hood along the score line. The hood may then simply be lifted over the head without contacting anything other than a user's hands (which will normally be covered in surgical gloves or the like if in a hazardous environment). The score line is positioned adjacent to the central seam. The score line may be formed when the central seam is formed, or alternatively may be stamped as the material of the hood is being cut. The score line may be configured so that it requires a 15N-30N force to tear the score line for removal of the hood.

A blister weld may be used to form the connector portion of the hood. The remaining features of the hood, such as the off centre valve, the central seam, the brow element and brow seam, the visor portion, apron connector, straps, skirt and hood body are as described with reference to the other drawings.

It is noted that features of each of the embodiments described above, specifically the embodiment shown as well as those optional features described in the text above may be combined with the features of the other embodiments. For example, the hood described may be combined with any suitable collar, but it may be preferably combined with the collar also described herein. The hood and the collar may however be used separately, and potentially for other applications where desired. Each of these elements described are intended to be combined together to form a single respirator that is particularly advantageous as it is effective at preventing the ingress of hazards from the outside environment, and is designed to provide required air flow, and to reduce the amount of noise generated, whilst being comfortable to wear for the user. The respirator as a whole is therefore highly advantageous over those that have come before, and the components are even more beneficial when used together as a respirator as a whole than when used apart. For example, the hood shape and the air outlet of the collar are designed together to create optimal air flow within the hood that avoids facial features of the user. Either hood or collar used without the other may provide some benefits but may not be as beneficial as when used together in the respirator as described above.