GB2490509A

GB2490509A - Particle collector apparatus

Info

Publication number: GB2490509A
Application number: GB1107328.5A
Authority: GB
Inventors: Malcolm Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-05-04
Filing date: 2011-05-04
Publication date: 2012-11-07
Also published as: GB2504442B; GB201107328D0; WO2012150571A1; GB201320498D0; GB2504442A

Abstract

Particle collector apparatus 220 comprising collection vessel 210 having inlet 230, outlet 240, vacuum generating unit 10 connected to outlet 240. Vacuum unit 240 is powered by movement of a first fluid, producing an at least partial vacuum that induces flow of a second fluid in a first direction through vessel 210 from inlet 230 to outlet 240. Vacuum unit 10 may utilise the Coanda effect and the Bernoulli principle to produce vacuum. The first fluid may be compressed air. Collection vessel 210 may be an impactor or impinger. Apparatus 220 may comprise a second vacuum generating unit that induces a second flow of fluid through collection vessel 220 in the opposite direction to the first direction. A method of collecting particles entrained in a second fluid comprises providing the particle collector apparatus 220, providing a source of particles in fluid connection with inlet 230, providing a first fluid, and controlling the flow of the first fluid through vacuum unit 10 to suck particles from the source of particles into collection vessel 210.

Description

A particle collector apparatus The present invention relates generally to a particle collector apparatus and to a method of collecting particles entrained in a fluid, and finds particular, although not exclusive, utility in the assessment of medical devices such as inhalers.

In this regard, the term inhaler refers to medical devices used by, for example, asthma sufferers for the dispensation and inhalation of pharmaceutical compositions.

In the development of inhalers it is necessary to test their operation. One of the areas requiring testing is the quantification of the different sizes of particles dispensed during use. Typically this is effected by means of impingers or impactors. In one embodiment, these may comprise a particle collection vessel including a series of sieves or filters for collecting particles of differing sizes. In another embodiment the impactors or impingers include one or more conduits including array(s) of bends which operate to collect different sized particles as they drop-out of their entrainment by virtue of inertia.

Other collection vessels are used which collect particles of all sizes as they exit the inhalers in use. The particles may be then analysed as required. The collection vessels may be dose collection tubes and may include filters for trapping the particles.

To mimic the effect of use a suction force, or at least partial vacuum, must be produced at the outlet of the inhaler and the outlet must be fluidly connected to the particle collection vessel.

The suction force is typically produced using a vacuum generator of the pump-type including a reciprocating piston and possibly an air receiver. However, these pumps suffer from mechanical failure, and are noisy and bulky. Furthermore, it is difficult to control the vacuum force effected through the particle collection vessel in a consistent manner leading to disparities in results from several identical tests.

It would therefore he desirable to have an improved apparatus and method for testing such inhalers.

In a first aspect, the invention provides a particle collector apparatus, for use in testing medical devices such as inhalers, comprising a collection vessel having an inlet, for connection with the device to be tested, and an outlet, and a first vacuum generating unit connected to the outlet, wherein the first vacuum generating unit is powered by a

I

first fluid to produce a first at least partial vacuum thereby inducing a flow of a second fluid in a first direction through the collec don vessel from the inlet to the outlet.

In this manner, the vacuum is not generated by apparatus of the type including a reciprocating piston. Rather, the vacuum generating unit of the invention has no moving parts. The vacuum generating unit may be of the type similar to those which comprise a moving flow of a first fluid in a conduit, the conduit having a branch pipe.

An at least partial vacuum is created in the branch pipe as the first fluid moves past its junction with the conduit.

Alternatively or additionally, the first vacuum generating unit may rely upon the Coander effect and Bernoulli principle in operation to produce the first at least partial vacuum.

The second fluid may be drawn through the collection vessel from the inlet to the outlet by a suction force induced by the first at least partial vacuum, and the apparatus may be arranged such that this second fluid mixes with the first fluid in the first vacuum generating unit.

The first fluid may he compressed air. Accordingly, the source of energy for operating the vacuum generating unit may be provided in reusable gas bottles and/or an air receiver filled by a compressor.

The apparatus may comprise a controller for controlling the first vacuum generating unit. In this way the first suction force created by the first vacuum generating unit may be finely controlled in that the flow of first fluid (possibly from the source of compressed gas) may be throttled or otherwise regulated to produce a consistent volume flow rate and/or pressure. The controller may be a flow regulator.

The apparatus may comprise a flow meter for measuring the rate of flow of the first fluid. The apparatus may comprise a flow meter for measuring the rate of flow of the second fluid.

The apparatus may comprise comprising an exhaust fluid trap for trapping the fluid exiting the collection vessel. This fluid may be the first and second fluids mixed together. The trap may be a water trap although other types are contemplated.

The collection vessel may be an impactor, impinger, dose collection tube, or any other collection means for collecting and possibly separating the particles into fractions.

The fractions may be based upon any one of size, weight and density of the particles.

The apparatus may comprise a second vacuum generating unit arranged to produce a second at least partial vacuum and inducing a second flow of fluid in a second direction through the collection vessel, wherein the second direction is substantially opposite to the first direction.

The two vacuum generating units may be connected in series or parallel.

In a second aspect, the invention provides a method of collecting particles entrained in a second fluid comprising the steps of providing apparatus according to the first aspect, providing a source of particles in fluid connection with the inlet of the collection vessel, providing a first fluid, controlling the flow of first fluid through the first vacuum generating unit thereby inducing a flow of second fluid through the collection vessel thus sucking in particles from the source of particles.

The first fluid may be compressed air. The second fluid may be air. The method may involve the mixing of the first and second fluids together due to the operation of the vacuum generating unit.

The method may further comprise the steps of providing a second vacuum generating unit as described herein, connecting it to the collection vessel, and controlling the first and second vacuum generating units to provide a flow of fluid through the collection vessel which altemates in direction thereby to simulate breathing.

In this way the test may more closely simulate actual use of an inhaler in that a user may not always just suck through it but may also breathe in and out through it.

It will be understood by the skilled person that such equipment allows for far better testing of inhalers and other such inhalation equipment in that it is more controllable, consistent, quieter in use and also relatively less expensive.

The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

Figure 1 is a cross-section of a vacuum generating unit according to one embodiment of the invention Figure 2 is a schematic plan of one particle collection apparatus; and Figure 3 is a schematic plan of another particle collection apparatus.

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto hut only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention desctibed herein are capable of operation in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other otientations than described or illustrated herein.

It is to be noticed that the term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B. Similarly, it is to be noticed that the term "connected", used in the description, should not be interpreted as being restricted to direct connections only. Thus, the scope of the expression "a device A connected to a device B" should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may be a path including other devices or means. "Connected" may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may refer to different embodiments.

Furthermore, the particular features, structures or characteristics of any embodiment or aspect of the invention may he combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

Similarly it should he appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamhning the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as tie following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are set forth.

However, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of

this description.

S

In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

The invention will now be described by a detailed description of several embodiments of the invention. It is clear that other embodiments of the invention can be configured according to the knowledge of persons skilled in the art without departing from the true spirit or technical teaching of the invention, the invention being limited only by the terms of the appended claims.

In Figure 1 a cross-section of a vacuum generating unit 10 is depicted. It is of the type sold by Vaccon Company, Inc. as a material conveying pump.

The pump 10 comprises a cylindrical body 20 having a bore comprising a central section 80 which has a substantially constant diameter, an inlet 90 having a bore which increases in diameter from the constant diameter of the central section to the axial end of the cylindrical body 20, and an outlet 100 also having a bore which increases in diameter from the constant diameter of the central section to the opposite axial end of the body 20.

A second cylindrical body 30 is provided immediately radially outside of the body 20 in the form of a ring, at a point approximately one-third of the axial length of the body 20 from one axial end thereof.

This second cylindrical body has an orifice 40 which leads into an inner annulus 50 provided as a hollow chamber in the form of ring within the cylindrical body 20.

This annulus 50 is connected to the central section of the bore of the body 20 by an array of passages 60. These passages are arranged such that their axial lengths are at an angle of approximately 45 degrees to the longitudinal axis of the body 20. They open into the central bore 80.

In use, compressed fluid, such as air, is directed into the orifice 40 in tlie direction as shown. It is forced (by its relatively high pressure) into the annulus 50 and thus via the passages 60 into the central section of the body 20.

Due to the Coander effect as the air passes from the passages into the central bore 80 its speed increases. The air then passes out of the unit tO via the outlet 100 in the direction shown.

Due to the arrangement of the passages 60 the air forms into a corkscrew rotating as it progresses down the bore 20 to the outiet 100.

The Bernoulli effect of decreased pressure with increased speed ensures that a lower pressure is produced at the inlet 90 of the unit 10. This may be considered to be a vacuum, or a partial vacuum, or merely an area of reduced pressure. However, it produces a sucking effect at the inlet 90 which may he utilised as described below.

In Figure 2, a particle collection apparatus (or inhaler testing apparatus) 200 is shown. It includes a particle collection vessel 210 comprising an inlet 230 at the top and an outlet 240 at the base. The vessel includes collection means for collecting various sizes of particles such that after use the different size fractions may he quantified.

The outlet 240 is connected to the inlet of a vacuum generating unit 10 by a pipe 250. The outlet 100 of the vacuum generating unit 10 is connected to a fluid trap 270.

This trap is optional and may comprise water for trapping gases or particles which have not been caught within the particle collection vessel.

The vacuum generating unit tO is powered by compressed air fed from a source of compressed air 290. This source is connected via a regulator 295.

A flow meter 285 is shown monitoring the rate of flow flowing between the particle collection vessel 210 and the vacuum generating unit 10. Another flow meter 300 is shown monitoring the rate of flow of compressed air flowing into the vacuum generating unit 10 from the source of compressed air 290. Either or both of these flow meters 285, 300 are optional.

Other forms of monitoring may be provided such as pressure gauges.

A controller 280 is provided for controlhng the apparatus 200. It is connected to the flow meters 285, 300, the source of compressed gas 290 and the regulator regulating the flow of compressed gas from the source 290 to the vacuum generating unit 10. The controller 280 may include a Cpu and/or be connected to a computer. In this way, the apparatus 20 may be controlled such that a consistent suction force (or reduced pressure) is applied to the outlet of the particle collection vessel 210 such that, in use, an inhaler or other such subject for testing, may be connected to the inlet 230 and have air or other fluids pulled through it.

Figure 3 shows a variation of the apparatus in Figure 2. The apparatus 201 includes all the same equipment, viz, the particle collection vessel 210, a vacuum generating unit 10, a gas trap 270, a controller 280, a source of compressed air 290, a flow regulator 295 and flow meters 285, 300. Accordingly, one way of operation involves the flow of compressed air A' from the source of compressed air 290 to the vacuum generating unit 10 such that it pulls air or other fluid A through the particle collection vessel 210 (via its inlet 230 and outlet 240) and directs it out of its outlet mixed with the compressed air A'.

However, the apparatus 201 also includes a second vacuum generating unit lOb.

This unit lOb is arranged in reverse in that its outlet is connected to the outlet 240 of the particle collection vessel 210 rather than its inlet.

The pipe 250, or other form of connection, from the outlet 240 of the particle collection vessel 210 still leads to the inlet of the first vacuum generating unit 10 but it now includes a branch 252 to the outlet of the second vacuum generating unit 1 Oh.

Furthermore, two valves 253, 254 are located in the pipes 251, 252 leading from the branch to the inlet of the first vacuum generating unit 10 and the outlet of the second generating unit I Oh respectively.

The second vacuum generating unit lOb is powered by the source of compressed air 290 in the same way as the first vacuum generating unit 10. This flow of compressed air is controlled by a regulator 296 which is in turn operated by the controller 280.

To operate the apparatus 201 such that instead of air being pulled through the particle collection vessel 210 by the first vacuum generating unit 10, air is pushed through it from the second vacuum generating unit lob, the valve 253 leading to the first vacuum generating unit 10 is closed and the valve 254 leading to the second vacuum generating unit lOb is opened.

At the same time the flow A' of compressed air to the first vacuum generating unit 10 is stopped and the flow B' to the second vacuum generating unit lOb is started.

In this way the first vacuum generating unit 10 ceases to pull air A or other fluid through the particle collection vessel 201 and instead air B is sucked in through the inlet of the second vacuum generating unit lOb and pushed into the outlet 240 of the particle collection vessel 210, such that a mixture of compressed air B' and the air B sucked in moves through the particle collection vessel 210 from its outlet 240 to its inlet 230 in a reverse direction to that described with reference to Figure 2.

If this direction is then reversed again by supplying compressed air to the first vacuum generating unit 10 and stopping it to the second vacuum generating unit lOb (along with the opening and closing of the relevant valves 253, 254) then the initial direction may be reproduced again.

A continuous repetition of these two states or directions of flow may simulate breathing cycles to more closely mimic actual use by a person.

In Figure 3, the controller 280 is shown connected to the various items of equipment by dotted hnes 281, 282, 283, 284, 286, 287 288. These indicate control lines which may he electrical, mechanical, direct and/or indirect as will be understood by a person familiar with such technology.

In this regard, although a controller 280 is shown it is possible that the apparatus be controlled manually or semi-manually.

Figures 2 and 3 depict particle collection vessels of the type known as impactors.

It is contemplated that these may be replaced or added to with other types of collection means such as impingers or dose collection tubes. More than one type of particle collector may be connected to the apparatus at one time.

Although shown as separate items the collection vessel and vacuum generating unit(s) may be integral with one another.

Claims

Claims 1. A particle collector apparatus, for use in testing medical devices such as inhalers, comprising a collection vessel having an inlet, for connection with the device to be tested, and an outiet, and a first vacuum generating unit connected to the outlet, wherein the first vacuum generating unit is powered by movement of a first fluid to produce a first at least partial vacuum thereby inducing a flow of a second fluid in a first direction through the collection vessel from the inlet to the outlet.
2. The apparatus of claim 1, wherein the second fluid is drawn through the collection vessel from the inlet to the outlet by a suction force induced by the first at least partial vacuum, and the apparatus is arranged such that this second fluid mixes with the first fluid in the first vacuum generating unit.
3. The apparatus of either one of claims I and 2, wherein the first vacuum generating unit relies upon the Coander effect and Bernoulli principle in operation to produce the first at least partial vacuum.
4. The apparatus of any preceding claim, wherein the first fluid is compressed air.
3. The apparatus of any preceding claim, comprising a controller for controlling the first vacuum generating unit.
6. The apparatus of any preceding claim, comprising a flow meter for measuring the rate of flow of the first fluid.
7. The apparatus of any preceding claim, comprising a flow meter for measuring the rate of flow of the second fluid.
8. The apparatus of any preceding claim, comprising an exhaust fluid trap for trapping the fluid exiting the collection vessel.
9. The apparatus of any preceding claim, wherein the collection vessel is an impactor or impinger.
10. The apparatus of any preceding claim, comprising a second vacuum generating unit arranged to produce a second at least partial vacuum and inducing a second flow of fluid in a second direction through the collection vessel, wherein the second direction is substantially opposite to the first direction.
Il. A method of collecting particles entrained in a second fluid comprising the steps of providing apparatus according to any one of claims 1 to 9, providing a source of particles in fluid connection with the inlet of the collection vessel, providing a first fluid, controlling the flow of first fluid through the first vacuum generating unit thereby inducing a flow of second fluid through the collection vessel thus sucking in particles from the source of particles.
12. The method of claim 11, further comprising the steps of providing a second vacuum generating unit according to claim 10, connecting it to the collection vessel, and controlling the first and second vacuum generating units to provide a flow of fluid through the collection vessel \vhtch alternates in direction thereby to simulate breathing.
13. A particle collector apparatus, for use in testing medical devices such as inhalers, substantially as hereinhefore described with reference to the accompanying drawings.
14. A method of collecting particles entrained in a fluid substantially as hereinbefore described with reference to the accompanying drawings.