GB2597484A

GB2597484A - Aerosol canister

Info

Publication number: GB2597484A
Application number: GB2011368.4A
Authority: GB
Inventors: Pallister Arthur; Schlaudraff Elsa
Original assignee: Innovolo Ltd
Current assignee: Innovolo Ltd
Priority date: 2020-07-22
Filing date: 2020-07-22
Publication date: 2022-02-02
Also published as: GB202011368D0; WO2022018205A1

Abstract

An aerosol canister 100 comprises a body portion 102 with an internal volume, and a barrier member 108 located within the body portion, the barrier member dividing the internal volume into a first chamber 110 for housing a propellant and a second chamber 112 for housing a payload. The second chamber is in fluid communication with the exterior of the body portion, preferably via a pipe 118, and the barrier member is movable, preferably by sliding, within the internal volume to reduce the volume of the second chamber and simultaneously increase the volume of the first chamber. The barrier member may include a sealing ring 126 in contact with the pipe, and may comprise a convex surface 116 extending into the second chamber, which may have a concave surface 132 sized to accommodate the convex surface.

Description

AEROSOL CANISTER

Field of the Invention

The present invention relates to an aerosol canister. The invention also relates to a kit of parts comprising a dispensing cap and an aerosol canister.

Background to the Invention

In standard aerosol canisters, a high-pressure propellant is suspended with a fluid to propel the fluid from the canister as an aerosol. These propellants are often volatile, hazardous and harmful to the environment. Further, standard aerosol canisters only allow low resistance, low viscosity fluids to be dispensed. As such, the viscosity of thick fluids must be lowered such that they may traverse the narrow pathways within an aerosol canister. With this aim, thinners are frequently used to assist the payload fluid in traversing these narrow pathways.

When such low viscosity fluids are released as an aerosol, the fluids quickly return to their original viscosity as the thinners evaporate. The evaporated thinners may cause a hazardous atmosphere local to the aerosol canister, causing pollution of the wider environment as well as posing risks within the canister environment. Additionally, thinners and propellants are often volatile substances, so there is a risk of explosion or damage to the canister as these volatile substances are suspended or housed in the same chamber as the payload.

As such, there is a need for an aerosol canister wherein the propellant is not suspended within the payload and further, wherein the need for volatile thinners, to lower the viscosity of the payload fluid, is reduced or eliminated.

Objects and aspects of the present claimed invention seek to alleviate at least these

problems with the prior art.

Summary of the invention

According to a first aspect of the invention, there is provided an aerosol canister, the aerosol canister comprising: a body portion comprising an internal volume, and a barrier member located within the body portion, the barrier member dividing the internal volume into a first chamber for housing a propellant and a second chamber for housing a payload; the second chamber in fluid communication with the exterior of the body portion, wherein the barrier member is movable within the internal volume to reduce the volume of the second chamber and simultaneously increase the volume of the first chamber.

In this way, a canister wherein the payload and propellant are housed separately is provided. In this way, the propellant is not suspended in the payload. As such, the aerosol released from the canister is substantially pure payload, as no propellant is released in the dispensing process. Such a canister also allows more environmentally -friendly, less hazardous and less volatile propellant substances to be used. For example, non-volatile propellants, such as nitrogen gas, or other compressible non-hazardous gases may be used as the propellant.

Preferably, the barrier member is slidably movable within the internal volume. Preferably, the second chamber is in fluid communication with the exterior of the body portion via a pipe. Preferably, the pipe extends from a first end located in the second chamber through the barrier member and the first chamber to the exterior of the body portion.

Preferably, the barrier member comprises a first sealing ring in contact with the pipe.

Preferably, the pipe comprises an elongate portion. Preferably, at least a portion of the pipe is coaxial with the longitudinal axis of the aerosol canister. Preferably, the first end of the pipe terminates adjacent to an interior surface of the second chamber.

Preferably, the pipe comprises a portion with a width of 5 mm or greater. More preferably, the entirety of the pipe has a width of 5 mm or greater. In this way, high viscosity fluids may traverse the pipe for dispensing from the canister as an aerosol. As such, the need for volatile thinners is reduced or eliminated. Such a feature may increase the safety and reduce the environmental impact of the aerosol canister.

Preferably, the aerosol canister comprises a valve for controlling the egress of the payload from the second chamber. In this way, the user manually controls the payload being dispensed from the canister. Preferably, the body portion comprises a resealable port for introducing propellant into the first chamber.

Preferably, the barrier member comprises a convex surface extending into the second 10 chamber. Preferably, the second chamber comprises a concave surface, wherein the concave surface is sized to accommodate the convex surface of the barrier member.

Preferably, the barrier member is movable to reduce the volume of the second chamber to less than 5% of the internal volume. More preferably, the barrier member is movable to reduce the volume of the second chamber to substantially zero. In this way, the entire payload content may be emptied from the second chamber.

Preferably, the barrier member comprises a second sealing ring in contact with an interior surface of the internal volume.

Preferably, the aerosol canister further comprises an attachment member for attaching a dispensing cap on to the aerosol canister. Preferably, the attachment member comprises a snap-fit attachment. Preferably, the attachment member is configured to permanently attach the dispensing cap on to the aerosol canister. In this way, there is a reduce risk of accidental separation of the dispensing cap from the aerosol canister.

Preferably, the barrier member is substantially annular. Preferably, the aerosol canister is 65 mm in diameter.

Preferably, each of the components of the aerosol canister comprises a detectable material. In this way, if any part of the aerosol canister is lost, for example within a food processing line, it can be detected without invasive or expensive techniques. For example, detection may be via metal detection, electromagnetic detection or magnetic detection.

According to a second aspect of the invention, there is provided a kit of parts comprising 5 a dispensing cap and the aerosol canister as described above.

Detailed Description

Embodiments of the present invention will now be described by way of example only 10 and with reference to the accompanying drawings, in which: Figure 1 depicts a deconstructed view of an aerosol canister in accordance with the first aspect of the present invention; and Figure 2 depicts an exploded view of the aerosol canister of Figure 1.

With reference to Figures 1 and 2, there is illustrated an aerosol canister 100 comprising a body portion 102. In this embodiment, the body portion 102 comprises a lower body portion 104 and an upper body portion 106. The lower body portion 104 is hollow and substantially cylindrical with a 65mm cross sectional diameter. The lower body portion 104 is closed at a first end and open at a second end. The upper body portion 106 comprises a convex shell which is open at a first end, with a circular cross section of 65mm diameter, and tapers to a closed second end with a circular cross section.

In use, the lower body portion 104 and upper body portion 106 form an assembly, wherein the open end of the lower body portion 104 and the open end of the upper body portion 106 connect to form an airtight connection. In this way, the body portion 102 comprises an internal volume, with the interior surfaces of the body portion 102 forming the external perimeter of the internal volume. A portion of the upper body portion 106 is located against an interior surface 130 of the lower body portion 104, when assembled. It is envisaged that the entire body portion 102 assembly is permanently connected, such that, in use, the body portion 102 forms a single, solid part. The aerosol canister 100 is 65mm in diameter.

The aerosol canister 100 further comprises a barrier member 108 located within the body portion 102. The barrier member 108 divides the internal volume into a first chamber 110 for housing a propellant and a second chamber 112 for housing a payload. In use, propellant housed in the first chamber 110 is housed under a pressure greater than atmospheric pressure. It is envisaged that the propellant may be in either the gas or liquid state. In use, payload, the fluid to be dispensed as aerosol by the aerosol canister 100, is housed in a liquid state within the second chamber 112.

The aerosol canister 100 further comprises a pipe 118 located within the internal volume, the pipe 118 comprising a first end 120 and a second end 122. The pipe 118 is coaxial with the longitudinal axis A of the aerosol canister 100. The pipe 118 extends from a first end 120 located within the second chamber 112, through the barrier member 108 and the first chamber 110 to the exterior of the body portion 102. In this way, the second chamber 112 is in fluid communication with the exterior of the body portion 102.

The second end 122 of the pipe 118 tapers to an elongate portion 124 comprising a uniform tube extending to the first end 120. In this way, the aperture at the second end 122 of the pipe 118 is larger than the aperture at the first end 120. The width of the elongate portion 124 is 6mm, such that the width along the entire length of the pipe 118 is 6mm or greater. The aperture at the first end 120 is slightly wider than the width of the elongate portion 124 to assist in fluid flow from the second chamber 112 into the pipe 118. This wide fluid path allows high viscosity fluids to traverse the pipe 118 without the need for mixing with thinners.

The barrier member 108 is a substantially annular shell comprising a cylindrical surface 114 and a convex surface 116. The barrier member 108 is coaxial with the longitudinal axis A of the aerosol canister 100. The cylindrical surface 114 spans the widest width of the body portion 102, such that the cylindrical surface 114 has a circular cross section with a diameter slightly less than the 65mm diameter of the lower body portion 104. In this way, the barrier member 108 abuts the interior surface 130 of the lower body portion 104, such that the barrier member 108 is not fixed and is movable within the internal volume. The barrier member 108 is open at the end adjacent the cylindrical surface 114 and the convex surface 116 extends into the second chamber 112.

The second chamber 112 comprises a concave surface 132 on the interior surface 130 of the lower body portion 104. The concave surface 132 is sized to accommodate the convex surface 116 of the barrier member 108. The pipe 118 extends from the second end 122 at the exterior of the body portion 102, through an aperture in the convex surface 116 such that the first end 120 terminates adjacent the concave surface 132. In this way, the first end 120 of the pipe 118 terminates adjacent to an interior surface of the second chamber 112.

The pipe 118 extends through the barrier member 108 such that the barrier member 108 abuts the pipe 118, whilst being movable within the internal volume. The barrier member 108 comprises a first sealing ring 126 in contact with the pipe 118. The first sealing ring 126 extends about the circumference of the pipe 118 and provides an airtight seal between the barrier member 108 and the pipe 118. In this way, propellant housed in the first chamber 110 cannot enter the second chamber 112 via any gap between the pipe 118 and the barrier member 108. Additionally, the barrier member 108 remains moveable within the internal volume. Further, the first sealing ring 126 prevents payload housed in the second chamber 112 from entering the first chamber 110.

The barrier member 108 further comprises a second sealing ring 128 in contact with the interior surface 130 of the lower body portion 104. The second sealing ring 128 provides an airtight seal between the barrier member 108 and the interior surface 130. The second sealing ring 128 extends about the circumference of cylindrical surface 114 of the barrier member 108, proximate where the cylindrical surface 114 meets the convex surface 116. In this way, propellant from the first chamber 110 cannot enter the second chamber 112 via any gap between an internal surface of the body portion 102 and the barrier member 108. Additionally, the barrier member 108 remains moveable within the internal volume. Further, the second sealing ring 128 prevents payload housed in the second chamber 112 from entering the first chamber 110.

The barrier member 108 is movable within the internal volume to reduce the volume of the second chamber 112 and simultaneously increase the volume of the first chamber 110. The barrier member 108 is slidably moveable in both directions parallel to the longitudinal axis A of the aerosol canister 100.

The barrier member 108 is moveable between a first position (shown in Figure 1) and a second position. In the first position, the volume of the first chamber 110 is at a minimum volume and the volume of the second chamber 112 is at a maximum volume.

In the first position, the volume of the first chamber 110 is less than the volume of the second chamber 112. As shown in Figure 1, in the first position, the open end of the barrier member 108 is located proximate the connection point between the upper body portion 106 and the lower body portion 104.

The barrier member 108 is moveable in continuous increments (i.e. continuously) between the first position and the second position, such that while the volume of the first chamber 110 increases, the volume of the second chamber 112 simultaneously, or concomitantly, decreases. In the second position, the convex surface 116 of the barrier member 108 is in contact with the concave surface 132 of the second chamber 112. In the second position, the volume of the first chamber 110 is at a maximum volume and the volume of the second chamber 112 is at a minimum volume. As the concave surface 132 is sized to accommodate the convex surface 116 of the barrier member 108, the barrier member 108 is movable to reduce the volume of the second chamber 112 to substantially zero, when the barrier member 108 is in the second position. In this way, the first chamber 110 is substantially equal to the internal volume when the barrier member 108 is in the second position.

The aerosol canister 100 further comprises a valve 138 for controlling the egress of payload from the second chamber 112. The valve 138 is coaxial with the longitudinal axis A of the aerosol canister 100. The valve 138 extends from a first end located within the second end 122 of the pipe 118, through an aperture in the upper body portion 106 to a second end in the exterior of the body portion 102. The valve 138 comprises a stem 140, a resilient member 142, a first valve sealing ring 144 and a second valve sealing ring 148. It is envisaged, the valve 138 can comprise additional components to assist with mating to a dispensing cap.

The stem 140 comprises an elongate tube with a width of 6mm comprising a first, open end located in the exterior of the body portion 102. In this embodiment, the stem comprises an 8mm OD (outer diameter) elongate tube, such that the inside diameter of the tube provides a 6mm wide pathway for fluid to traverse. The open end extends beyond the exterior surface of the upper body portion 106. The stem 140 tapers towards a second, closed end located within the second end 122 of the pipe 118. The resilient member 142 is located about the closed end of the stem 140.

The width of the pipe 118 and the stem 140 is at least 6mm along a substantial portion of the pipe 118 and stem 140. In this way, a wide passage for the payload is provided, allowing high viscosity fluids to traverse the pipe 118 and stem 140 and exit into the exterior of the body portion 102. The large cross sectional area of the pipe 118 and stem 140 allows high resistance viscous fluids, such as thick grease, to be dispensed from the aerosol canister without thinning components.

The resilient member 142 is a spring with a first end abutting the interior wall of the pipe 118 and with a second end abutting the closed end of the stem 140. In this way, the resilient member 142 and stem 140 are coupled such that a downwards force on the stem 140 compresses the resilient member 142. It is envisaged that the resilient member 142 may be affixed to the pipe 118 at its first end and/or the stem 140 at its second end.

The first valve sealing ring 144 and second valve sealing ring 148 are both in contact with the upper body portion 106 and the stem 140, forming an airtight seal. In this way, payload in the pipe 118 cannot exit into the exterior of the body portion 102 through any gap between the body portion 102 and the stem 140. The first valve sealing ring 144 is located where the stem 140 enters the pipe 118. The second valve sealing ring 148 is located proximate the exterior of the body portion 102.

The valve 138 is movable between a closed position wherein the valve 138 is fully closed and an open position wherein the valve 138 is fully open. The closed position of the valve 138 is shown in Figure 1, wherein no actuation force is applied to the valve 138. The valve is biased to the closed position by a force provided by the resilient member 142.

The stem 140 further comprises a payload aperture 146 located proximate the closed end of the stem 140. The payload aperture 146 comprises four circular apertures located symmetrically about the longitudinal axis A of the aerosol canister 100. The payload aperture 146 is located adjacent the first valve sealing ring 144, such that the portion of the surface of the stem 140 within the pipe 118 in the closed position is solid. In this way, payload in the pipe 118 is prevented from entering the stem via the payload aperture 146 when the valve is in the closed position. In the closed position, the payload aperture 146 is located on a portion of the stem 140 which is in contact with the upper body portion 106.

To actuate the valve 138, the user pushes down on the valve 138, applying an activation force to the open end of the stem 140. The actuation force is transferred through the stem 140 such that the resilient member 142 is compressed and a portion of the stem 140 lowers into the pipe 118. The first valve sealing ring 144 loses contact with the upper body portion 106 such that an airtight seal is no longer sealed. Additionally, the payload aperture 146 is lowered such that the portion of the stem 140 in which the payload aperture 146 is located reduces contact with the upper body portion 106, until the payload aperture 146 loses contact with the upper body portion 106 in the open position. In this way, the payload in the pipe 118 can enter the stem via the payload aperture 146. When the actuation force is removed, the valve 138 returns to the closed positon and payload is prevented from entering the stem and exiting the aerosol canister 100.

The valve 138 can be positioned between the closed position and open position such that the egress of payload from the second chamber 112 is controlled. The flow rate of payload exiting the stem 140 is increased as the valve 138 is moved towards the open position, such that in the open position a maximum payload flow rate is achieved.

In use, the propellant in the first chamber 110 is housed under pressure, such that the propellant provides a propelling force against the barrier member 108. This force is opposed by a reaction force from the payload housed in the second chamber 112. As such, when payload egresses the second chamber 112, the propelling force provided by the propellant overcomes the reaction force and the barrier member 108 slidably moves towards the second position. In this way, the volume of the second chamber 112 reduces and the volume of the first chamber 110 simultaneously increases. A propelling force is provided by the propellant at least until the barrier member 108 is moved to the second position.

As such, when the valve 138 is actuated, payload is propelled by the propelling force such that payload enters the stem 140 and exits into the exterior of the body portion 102. Payload exits the second chamber 112 and traverses through the pipe 118 and the stem 140 until the valve 138 is in the closed position and the payload can no longer exit the aerosol canister 100 via the payload aperture 146.

The body portion 102 further comprises a resealable port 150 for introducing propellant into the first chamber 110. The resealable port 150 comprises a passage 152, a port member 154, a first port sealing ring 156 and a second port sealing ring 158. The resealable port 150 is moveable between a sealed position, as shown in Figure 1, and an open position. The resealable port 150 is biased to a sealed position by a spring and the resealable port 150 is arranged such that a portion of the resealable port 150 remains at the exterior of the body portion 102 for user actuation.

The passage 152 is located within the upper body portion 106 and connects the first chamber 110 to a propellant aperture 160 located in the stem 140. In this way, a pathway between the exterior of the body portion 102 and the first chamber 110 is provided.

The port member 154 extends from the first chamber 110, through the upper body portion 106 and to the exterior of the body portion 102. When the resealable port 150 is sealed, the port member 154 seals the entrance of the passage 152 in the first chamber 110, preventing propellant housed in the first chamber 110 from entering the passage 152.

The first port sealing ring 156 and second port sealing ring 158 are both in contact with the upper body portion 106 and the port member 140, forming an airtight seal. In this way, propellant in the first chamber 110 cannot exit into the exterior of the body portion 102 or the passage 152 through any gap between the body portion 102 and the port member 154. The first port sealing ring 156 is located inside the first chamber 110 where the port member enters the first chamber 110. The second port sealing ring 158 is located proximate the exterior of the body portion 102.

The first chamber 110 can be refilled with propellant via the resealable port 150. The user provides propellant, under force at the open end of the stem 140. To open the resealable port 150, a user applies a force to the port member 154, such that the port member 154 lowers into the first chamber 110. The first port sealing ring 156 loses contact with the upper body portion 106 such that an airtight seal is no longer formed. In this way, user provided propellant can be forced into the first chamber 110 via the stem 140, propellant aperture 160 and passage 152. The user provided propellant is inserted into the stem 140 under a greater pressure than the propellant housed in the first chamber 110, such that the force of propellant entering the first chamber 110 is greater than the force provided by the housed propellant trying to exit the first chamber 110. In this way, the user provided propellant begins refilling the first chamber 110 and no propellant is allowed to exit the aerosol canister 100.

The resealable port 150 extends the life of the aerosol canister 100 by allowing the user to refill the canister with propellant. Increasing the quantity of propellant in the first chamber 110 increases the pressure provided by the propellant on the barrier member 108. In this way, the force acting to propel payload from the canister is maintained and substantially the entire payload housed in the second chamber 112 can be propelled from the aerosol canister 100. This reduces waste such that a more environmentally friendly aerosol canister is provided.

In certain embodiments, the resealable port 150 also allows for the introduction of propellant from the first chamber 110 into the stem 140 of the valve 138. When the resealable port 150 is in an open position, propellant enters the passage 152 from the first chamber 110 and enters the stem 140. This allows the user to clear the stem 140 of payload. Propellant may only enter the stem 140 via the propellant aperture 160 when the valve 138 is in the closed position, as actuation of the valve 138 lowers the stem 140 such that the propellant aperture 160 is blocked by the body portion 102. In this way, propellant can only enter the stem 140 when the valve 138 is closed, the resealable port 150 is opened and there is no opposing force, such as that from user provided propellant at the open end of the stem 140.

To open the resealable port 150, a user applies a force to the port member 154, such that the port member 154 lowers into the first chamber 110. The first pod sealing ring 156 loses contact with the upper body portion 106 such that an airtight seal is no longer formed. In this way, propellant in the first chamber 110 can enter the stem 140 via the passage 152 and propellant aperture 160. The force of the propellant entering the stem 140 is such that any payload within the stem 140 is ejected into the exterior of the body portion 102 along with the propellant. In this way, the stem 140 can be substantially cleared of fluid through actuation of the resealable port 150. When the force is removed from the port member 154, the resealable port 150 returns to the sealed positon and propellant is prevented from exiting the first chamber 110.

The resealable port 150 allows for clearing of the valve 128 without the need to invert or move the aerosol canister 100. Additionally, the propellant ejected via the resealable port 150 can additionally clear and clean a dispensing cap attached to the aerosol canister 100. This improves ease of cleaning the aerosol canister and any attached cap.

The aerosol canister 100 further comprises an attachment member for attaching a dispensing cap on to the aerosol canister 100. In this embodiment, the attachment member comprises a raised lip 180 extending from the exterior surface of the upper body portion 106, complementary to the width of the lower body portion 104. The raised lip 180 extends about the circumference of the upper body portion 106. In this way, the raised lip 180 has a 65mm diameter and is symmetrical about the longitudinal axis A of the aerosol canister 100.

When the body portion 102 is assembled, the raised lip 180 is in contact with the lower body portion 104. To attach a dispensing cap, a portion of the dispensing cap is forced to resiliently deform over the raised lip 180, such that a strong connection between the portion of the dispensing cap and the lower body portion 104 and the raised lip is established. The convex shell shape of the upper body portion 106 and a curved surface 136 of the raised lip 180 assist in resiliently deforming the portion of the dispensing cap. In this way, a snap-fit attachment is provided.

The attachment member further comprises a mating member 170 extending from the exterior surface of the upper body portion 106. The mating member 170 is located about the stem 140 of the valve and extends about the circumference of the upper body portion, such that the mating member 170 has a 32.5mm diameter and is symmetrical about the longitudinal axis A of the aerosol canister 100. A portion of the dispensing cap can then snap fit over the mating member 170 to provide a second attachment point on the aerosol canister 100. The mating member 170 further improves mating of the aerosol canister 100 with a dispensing cap. Upon attachment, the stem 140 of the valve and the body portion 102 are in contact with the dispensing cap. In this way, the user may engage with the dispensing cap to, in turn, actuate the valve 138. It is envisaged that the stem 140 of the valve 138 engages with dispensing cap entry point without requiring a reducing adaptor. It is envisaged that the shape, diameter and location of the attachment member on the body portion 102 are selected for mating with the desired dispensing cap/s for the aerosol canister 100 application.

In many applications, it is beneficial for the dispensing cap to become permanently attached to the aerosol canister 100. As such, the attachment member is configured for permanent attachment of the dispensing cap to the aerosol canister 100. In this way, a substantial separating force is required to remove the dispensing cap from the aerosol canister. This reduces the risk of accidental separation of the cap from the canister.

It is further understood that the dispensing cap may be removably retained on the aerosol canister 100 such that the cap may be removed, for example, for maintenance and replacement. It is envisaged that the attachment member may be any suitable attachment member located on the aerosol canister 100, in particular located on the body portion 102, for attachment of one or more types of dispensing cap. In particular, the attachment member is suitable for attachment to a dispensing cap comprising a 6mm payload pathway, in particular a cap which has a 4mm or 8mm inlet port, accessed by removing the reducer in the cap which is provided to accommodate traditional 4mm spigot aerosol canisters.

Further embodiments within the scope of the present invention may be envisaged that have not been described above, for example, it is envisaged that the aerosol canister comprises a safety line attachment portion such that the user can attach a fall arrest safety line for anchoring the canister to a fixed point, such as on the user, equipment or the external environment, to reduce the risk of loss of the canister. Additionally, it is envisaged that the canister comprises additional parts for ease of mating to a dispensing cap, such as an 0 ring. It is envisaged that the aerosol canister can be fully factory-assembled such that it may be auto-filled with payload and propellant. It is envisaged that in many embodiments the aerosol canister is made from a biodegradable and/or recyclable materials, such as aluminium. Additionally, the aerosol canister is resistant to degrading or damage from the contents, is able to withstand propellant pressure safety margins, withstand drop testing and conforms to the required health and safety regulations and requirements required by its application. In a further embodiment, the aerosol canister comprises a cylindrical body, a main valve closure, a piston, a spigot product and gas valve, a spray cap clearance push valve and optional insertion of a piston spring to assist dispensing. The invention is not limited to the specific examples or structures illustrated; a greater number of components than are illustrated in the figures could be used, for example.

Claims

Claims 1 An aerosol canister, said aerosol canister comprising: a body portion comprising an internal volume, and a barrier member located within said body portion, said barrier member dividing said internal volume into a first chamber for housing a propellant and a second chamber for housing a payload; said second chamber in fluid communication with the exterior of said body portion, wherein said barrier member is movable within said internal volume to reduce the volume of said second chamber and simultaneously increase the volume of said first chamber.
2. The aerosol canister of claim 1, wherein said barrier member is slidably movable within said internal volume.
3. The aerosol canister of claim 1 or claim 2, wherein said second chamber is in fluid communication with said exterior of said body portion via a pipe.
4. The aerosol canister of claim 3, wherein said pipe extends from a first end located in said second chamber through said barrier member and said first chamber to said exterior of said body portion.
5. The aerosol canister of claim 4, wherein said barrier member comprises a first sealing ring in contact with said pipe.
6. The aerosol canister of claim 3, claim 4 or claim 5, wherein said pipe comprises an elongate portion.
7. The aerosol canister of any one of claims 3 to 6, wherein at least a portion of said pipe is coaxial with the longitudinal axis of said aerosol canister.
8. The aerosol canister of any one of claims 3 to 7, wherein said first end of said pipe terminates adjacent to an interior surface of said second chamber.
9. The aerosol canister of any one of claims 3 to 8, wherein said pipe comprises a portion with a width of 5 mm or greater.
10. The aerosol canister of any one of claims 3 to 9, wherein the entirety of said pipe has a width of 5 mm or greater.
11. The aerosol canister of any one preceding claim, wherein said aerosol canister comprises a valve for controlling the egress of said payload from said second chamber.
12. The aerosol canister of any one preceding claim, wherein said body portion comprises a resealable port for introducing propellant into said first chamber.
13 The aerosol canister of any one preceding claim, wherein said barrier member comprises a convex surface extending into said second chamber.
14. The aerosol canister of claim 13, wherein said second chamber comprises a concave surface, wherein said concave surface is sized to accommodate said convex surface of said barrier member.
15. The aerosol canister of any one preceding claim, wherein said barrier member is movable to reduce the volume of said second chamber to less than 5% of said internal volume.
16. The aerosol canister of any one preceding claim, wherein said barrier member is movable to reduce the volume of said second chamber to substantially zero.
17. The aerosol canister of any one preceding claim, wherein said barrier member comprises a second sealing ring in contact with an interior surface of said internal volume.
18 The aerosol canister of any one preceding claim, wherein said aerosol canister further comprises an attachment member for attaching a dispensing cap on to said aerosol canister.
19. The aerosol canister of claim 18, wherein said attachment member comprises a snap-fit attachment.
20. The aerosol canister of Claim 19, wherein said attachment member is configured to permanently attach said dispensing cap on to said aerosol canister.
21. The aerosol canister of any one preceding claim, wherein said barrier member is substantially annular.
22.The aerosol canister as claimed in any one preceding claim, wherein said aerosol canister is 65 mm in diameter.
23.A kit of parts comprising a dispensing cap and the aerosol canister of any one preceding claim.