This disclosure relates to a method of orthonasal evaluation, and to a device that permits such evaluation.

The ability to predict what fragrances and flavours consumers will like is critical to the success of a fragrance and flavour company. Traditionally, flavour preference information has been gathered through panel testing techniques during which panellists taste and evaluate actual food or beverage samples. However, this process is limited by logistical factors such as product preparation, distribution, storage and serving conditions, plus by physiological factors such as sensory fatigue and satiety. These factors combined serve to limit the number of products which can be evaluated at one time and make flavour preference determination a time-intensive and laborious job.

It lias long been established that there is a strong correlation between taste and smell and that flavours liked when evaluated by smell tend to be liked when evaluated by taste, and vice versa. Thus, one proposed alternative to traditional panel testing techniques as described above is so-called orthonasal evaluation, which involves presenting human test subjects with volatile materials to be inhaled through the nose, a technique more often associated with fragrance preference determination. Employment of orthonasal evaluation techniques circumvents many of the limitations inherent in traditional flavour testing. For instance, as panellists arc evaluating flavour samples by smell, application support for product development is eliminated. Similarly, as subjects are not ingesting samples, satiety, fatigue and carryover effects associated with product consumption are minimised.

Orthonasal evaluation can be carried out using a variety of tools and techniques, for example by using scent pens, or scent bottles and absorbent paper smelling strips. However, these techniques are wasteful, suffer from inaccurate dosing and are labour- and time- intensive. Additionally they leave open the possibility of contamination of surfaces with liquid samples. In addition, the metering of blends in particular proportions has been problematic.

These difficulties have been substantially overcome by specialised devices that provide multiple reservoirs and suitable valving and mixing arrangements that permit the blending of particular odours. A typical example is described in US patent 6067842. Although such devices have been used successfully, they have the disadvantage of being quite large and requiring substantial ancillary equipment. To date, effective miniaturisation has not proved possible.

It has now been found that many of these problems may be substantially or even completely overcome by means of a novel method. There is therefore provided a method of orthonasal evaluation of a fluid, comprising the metering of the fluid in a defined quantity to provide a desired orthonasal combination, metering being accomplished from a plurality of fluid reservoirs, each containing a different fluid, according to inputs from a control unit, the defined quantities being provided by means of a metering device comprising

(a) a plurality of channels, each corresponding with an individual reservoir, the channels being formed in a surface and adapted to receive a flow of fluid, and which channels are covered by an elasticaSly-deformable membrane;

(b) valve means associated with each channel, comprising an element mounted

orthogonally to each channel and capable of moving into fluid flow-blocking contact against the pressure of the membrane, the profile of the element matching that of the channel profile at the point of contact; and

(c) valve-closing means.

There is additionally provided an orthonasal testing device, comprising a plurality of reservoirs each containing a fluid, at least one sampling port, a control unit and a metering device, the metering device comprising:

(a) a plurality of channels formed in a surface and adapted to receive a flow of .fluid, which channels are covered by an elastically-deformable membrane;

(b) each channel has an. associated valve means, the valve means comprising an element mounted orthogonally to each channel and capable of moving into fluid flow-blocking contact against the pressure of the membrane, the profile of the element sufficiently matching that of the channel profile at the point of contact; and. (c) valve-closing means.

The fluid reservoirs may be any suitable fluid reservoirs. (It should be noted here thai, while a plurality of reservoirs is mentioned, it is possible to have such a device with a single reservoir, and this possibility is encompassed by the use of the plural). For example, the reservoir may be a vial of liquid, or it may be a cylinder of vapour phase material, either under pressure or at atmospheric pressure. In the case of a fluid under pressure, the pressure may be used to provide the driving force of the fluid to the sampling port. In the case of a fluid at atmospheric pressure, a means of conveying it to the sampling port wit! be needed. This is typically either a ventilation means using air or a stream of a suitable carrier gas.

In a particular embodiment, the reservoir may be a vapour-phase substance-containing cartridge, each cartridge comprising a reservoir and channels to provide ingress of carrier gas and egress of entrained vapour-phase substance, the channels being capillaries of such dimensions that there is little or no vapour escape in the absence of carrier gas flow. Such reservoirs are described in European Patent 1 523340 and are referred to hereinafter as ''credit card reservoirs". These have the advantages that they can be small and very slim (about credit card-sized, hence the name) and that they need no valve arrangements, merely a supply of carrier gas to entrain the substance from the cartridge and means of directing and regulating this. The carrier gas may be supplied from a carrier gas supply, which may be separate from the vapour-phase substance delivery device, or, if the quantities of vapour- phase substance are sufficiently small, integral with it.

The nature of the fluid reservoirs to be used will be determined to some extent by the relative location of the reservoirs and the metering device. It is possible to locate the reservoirs either upstream of or downstream from the metering device, with respect to the direction of flow of fluid. Thus, if the reservoirs are positioned downstream from the metering device (which has the advantage of reducing contamination), the reservoirs cannot be pressurised cylinders and must be of a form in which a carrier gas or a ventilation system can be used to convey fluid therefrom. In such a case, the "fluid" conveyed by the channels will be carrier gas. In the case of reservoirs mounted upstream, the fluid will be the olfactory fluid, plus carrier gas. Depending on which form of device is desired, the skilled person can easily select a suitable reservoir. In a particular embodiment, the fluid reservoirs are located downstream from the metering device and the reservoirs are credit card reservoirs.

The metering device comprises channels formed in a surface. The channels may be achieved by any convenient means, which means will depend to some extent on the nature of the surface. For example, they may be moulded into the surface as it is formed, or engraved or etched into an already- formed surface. The nature of the surface is not narrowly critical, but it must be stable with respect to operating conditions. For example, it must not react chemically with any fluid that passes through the channel. Typical examples of suitable materials are metals, such as stainless steel or suitable metal alloys, ceramics and suitable polymeric substances, a particular example being silicones. Alternatively, the channels may be formed in a relatively cheap and/or potentially chemically-reactive material and the channels then lined with a suitable thickness of a chemically impervious substance. For example, the channels could be formed in a block of polymethyl

methacrylate, and the surface of the channels, or even the entire channel -bearing surface of the block, and then coated with a suitable chemically-resistant material, such as a silicone. i a particular embodiment, the channels are moulded into a block of silicone polymer. Many kinds of silicone may be used, and the skilled person can easily select a suitable material. A typical material is polydimethy! siloxane. One example of such a material that is commercially available is SyIgard ^I 184 Silicone Elastomer (ex Dow Corning).

The dimensions of the channels may vary over a wide range of sizes, but they will be dictated by the desired size of the device and the number of channels desired. A large number of channels will naturally require smaller dimensions for a given device size. A typical channel may be, for example, 1 mm wide and 0.5mm deep, but it is emphasised that this is only given by way of example, and there are many other possibilities.

The cross-sectional profiles of the channels is not narrowly critical, and will usually be determined by the material in which they are formed and the methods by which they are formed. Thus, for a channel engraved or machined in metal, a rectangular or square cross- section is easily achieved. In the case of a moulded channel, it is generally better to have a cross-sectional form in which the top of the channel is wider than the bottom, for example, triangular, hemispherical and trapezoidal - this makes mould release easier, and has no effect on the functioning of the channel. The angle that the sides of the channel subtend with the perpendicular to the surface is not critical, but naturally the greater the deviation from the perpendicular the wider the top of the channel and therefore the fewer channels that can be accommodated on a given surface. The selection of a suitable channel cross- section and angle for any given material is entirely within the skill of the art.

The channels arc covered by an elastically-deformable membrane. This may be applied to individual channels, or it may be applied to the channel -bearing surface as a whole, being held in place by any suitable means such as adhesives. heat-sealing or welding and plasma bonding. The material may be any suitable elastically-deformable material that can withstand repeated elastic deformations and will return to its rest position when the cause of deformation is removed. It must naturally also be chemically resistant to any material that passes down the channel. Typical examples of suitable materials include silicones. The same types that can be used as the surface material may be used.

The thickness of the membrane is dependent to some extent on the material used, but it is typically from 0.1 -1.0mm thick. This is not to say that thicknesses outside this range cannot be used, but very thin membranes are more likely to encounter fragility problems, resulting in early failure, while thicker membranes are more robust, but may lack the necessary flexibility to be good valve members. A suitable membrane having the desired degrees of robustness and flexibility is of the order or 0.15-0.30mm.

With each channel there is associated valve means, comprising the following elements:

(i) an element mounted orthogonally to each channel and capable of moving into fluid flow-blocking contact against the pressure of the membrane (hereinafter the "closing element"); and

(ii) valve-closing means.

By "orthogonally" is meant that the movement of the closing element is essentially

perpendicular to the axis of the channel. The closing element may be in any suitable form, but is typically a rod that may be caused to move into valve-closing engagement with the channel. The fluid flow-blocking contact may be achieved by any convenient means. Basically, it means that the end of the closing element has a profile sufficiently similar to that of the profile of the channel at the point of contact, such that the elastically-deformable membrane is urged into flow-blocking contact with the channel, In the simplest embodiment, the profile of the closing element matches the cross-sectional profile of the channel.

In a particular embodiment, there is provided in the channel a valve section that permits easier and more efficient contact. In a typical embodiment, this valve section will take the form of a widening and/or deepening of the channel in the vicinity of the point of contact. One typical example is the formation of a circular depression into and out of which tire channel flows. In a further embodiment, there is provided in this widening and/or deepening a valve seat. This typically has the form of a wall mounted transversely to the axis of the channel across the entire width of the widening and extending vertically towards, but not contacting across its entire width, the membrane, thus defining a means of fluid passage. The wall has a crest in which is formed a concave profile, which essentially matches the closing element profile. In a typical example, the closing element profile will comprise a convex curve and the wall crest will have a matching concave curve.

Such a valve section may be part of an insert placed in a pre- formed channel, or it may be machined or moulded into the surface.

The valve-closing means that closes the closing element may he any suitable element known to the art. For example, it may be a solenoid acting in response to signals from a control unit. One particular example is a relay, in particular, a bistable relay. In a further particular embodiment, the valve-closing means is a piezoelectric motor. These motors rely for their operation on the change in shape of piezoelectric crystals when a signal is applied to them. They have the advantage of being able to be made very small, which contributes to the overall miniaturisation of the device, and of having very few operating parts, which improves reliability. The nature of the piezoelectric motor is not critical, and many types are commercially available, for example the Squiggle ¹ motors of New Scale

Technologies, Inc.

The control unit associated with the device comprises means for storing information relevant to the operation of the device, and to operate the device according to the desired olfactory sensation. Information includes information such as the natures of the contents of the reservoirs and the physical parameters needed to supply these contents in the right proportions, when required. Such parameters may include carrier gas flow rates, valve opening and closing times and sequences.

The control unit must also be able to adjust total flow to compensate for a change in total fluid ic resistance due to change in the number of opened channels. For example, when several channels need to be simultaneously in operation, the flow in the individual channels provided by a constant pressure source will tend to increase, analogously to electrical current in resistances in parallel when subjected, to a constant voltage. Thus the control unit must be programmed to compensate for this by reducing the flow. This may be achieved by a number of means, for example, by making the valves hereinabove described such that they can close to varying degrees, rather than be simple open and shut types, or by providing at least one switchablc prc-resi stance to regulate the overall flow.

All. of these details may be programmed into the control unit, which can then respond to commands for particular blends input into the device by any convenient means, such as a keypad or a touch screen, which may be integral with the device or separate, for example, a laptop or tablet computer programmed with appropriate software.

The software needed to perform the operations hereinabove described is either readily available commercially, or it may be a modification of such software that can easily be performed by a skilled software engineer. In operation, an operator will select a desired aroma, which is a combination of selected proportions of individual fluids held in the individual, reservoirs, and will enter these into the control unit. The control unit will then instruct the device to commence the transfer of the particular fluids by causing them to be conveyed to a mixing chamber via individual channels on the metering device hereinabove described. Flow sensors associated with each channel will measure the individual flows, and when the correct quantity of a particular material, has been metered, the control unit will activate the closing element associated with the channel through which that material is being transferred and stop it. When the testing of that particular aroma is complete, the channels may be purged, ready for further aroma dispensing. The device has proved particular adept at providing excellent results at low flow rates. It can. also be made in hitherto impractical small sizes, so that, it can be carried in a briefcase or even, a pocket, overcoming the size problems of previous devices,

The disclosure is further described with reference to the accompanying drawings, which depict particular embodiments, and which are not meant to be in any way limiting.

Figure 1 is a perspective view of a lluidic block, that forms the basis of a metering device, which is adapted to provide carrier gas to a plurality of fluid reservoirs located downstream .from, the block.

Figure 2 is a schematic perspective view of a channel of Figure 1 with associated valve arrangement.

Figure 3 is a schematic transverse cross-section across the channel of Figure 2 along the line A-A'

In Figure 1 , there is generally depicted a fluidie block lconsidting of a block 2 of silicone resin (Sylgard 184 Silicone Elastomer (ex Dow Corning)), The ancillary equipment is not shown, but its nature will be understood from the following description.

Cast into the surface of the block. 2 is a network of interconnected channels, commencing at an inlet 3 through which, conies a carrier gas. In the direction of flow, the channels comprise a pre-resistanee network 4. leading to a distribution channel 5. from which lead a plurality of individual channels 6, one per fluid, reservoir (not shown). Each, channel leads to an individual outlet, port 8 and has a valve member 7, In this case, each channel has a width at the top of 1mm, a depth, of 0.5mm and the angle of the channel walls is 30° from the perpendicular.

The valve member ? is shown in greater detail in Figure 2. It comprises a circular depression 8, of larger diameter than the width of the channel (in this case 3mm diameter), but of the same depth. Positioned diametrically across the circular depression and placed transversely to the longitudinal axis of the channel is a wall 9 of 0,2mm thickness. This rises vertically from, the floor of the depression, and has formed in its crown an arcuate concave depression 10, such that this portion does not. in a rest, position, contact an el.astom.erie membrane (see Figure 3). The lowest point of the arcuate depression is, in this particular embodiment, 0.3mm below the surface.

Figure 3 shows a. 0.25mm thick, elastomeric silicone membrane 1 1 , also of Sylgard ^{1 M} 184 Silicone Elastomer. The membrane is adhered to the surface by plasma bonding, and covers the entire surface such that the channel forms a conduit capable of conveying carrier gas to a reservoir. Above this is positioned a valve-closing means 12. This has the form of an elongate member whose downward-facing end 13 has essentially the same profile as the arcuate concave depression. 10, such that, when it is caused to move downwards against the elastomeric membrane, it pushes the membrane into contact with the arcuate depression, matching exactly its profile, and. thus sealing off the possibility of flow. Thus, in. operation, a. signal, from a control unit (not shown) will cause the valve-closing means 12 to move into contact with the arcuate depression. 10, sealing off flow-' in the associated channel. A further signal will cause it to open. Thus, a series of parallel channels may be operated, regulating the flow of carrier gas to desired fluid reservoirs located downstream from the fluid block. The flow is regulated by means of the pre~resi stance channel 4, which is also equipped with, valves of the type in the channels and closed and opened by the same type of valve-closing means. Instructions from the control, unit to these valve-closing means ensures that a constant carrier gas flow is maintained, regardless of how many channels are simultaneously in use. The various selected fluids are conveyed by the carrier gas to a. final mixing chamber and associated sample port (not shown).

The skilled, person will readily understand that there are many variants of the device hereinabove described, which can be realised using only the ordinary skill of the art, and which therefore fall within, the scope of this disclosure.