GB2421436A

GB2421436A - Wick Assemblies

Info

Publication number: GB2421436A
Application number: GB0427969A
Authority: GB
Inventors: Richard Paul Hayes-Pankhurst; Peter William Ross
Original assignee: Carbonate Ltd
Current assignee: Carbonate Ltd
Priority date: 2004-12-21
Filing date: 2004-12-21
Publication date: 2006-06-28
Anticipated expiration: 2024-12-21
Also published as: GB2421436B; GB0427969D0

Abstract

A wick assembly for, for example, a fragrance dispenser such as an air freshener comprises a conventional wick (11) that wicks the liquid from a source (17). The liquid is evaporated from the wick (11) using a mat (13) of conductive fibres connected to a power source to heat the mat. In one embodiment, the liquid wicks along the wick (11) and into the mat (13) for evaporation and in an alternative embodiment the mat (13) is wrapped around the wick.

Description

WICK ASSEMBLIES

The invention relates to wick assemblies and, in particular, wick assemblies for use in vapour dispensers such as air fresheners and insecticide dispensers.

A known wick assembly for a vapour dispenser such as an air freshener comprises a wick for conveying a liquid from a source and a heated ceramic collar surrounding, but not in contact with, a portion of the wick remote from the liquid. The ceramic collar is connected to a source of power and heats the wick by convection to evaporate liquid from the wick.

It is a disadvantage of such an arrangement that the ceramic collar has significant thermal mass. In addition, the gap between the collar and the wick slows the transfer of heat from the collar to the wick. Accordingly, when power is supplied to the collar, there is a time delay before the liquid is evaporated. This can be disadvantageous since, for example, it is not apparent whether the device is working or not when it is first switched on. In addition, evaporation takes place only from that portion of the surface of the wick that is heated and this provides only a limited area for evaporation.

According to the invention, there is provided a wick assembly for evaporating a liquid comprising a wick for conveying a liquid from a source and a heater for heating and evaporating liquid from the wick, the heater being formed from a fibrous material including electrically conductive fibres.

The following is a more detailed description of some embodiments of the invention, by way of example, reference being made to the accompanying drawings in which:- Figure 1 is a side elevation, partly in section, of an air freshener showing a fragrance container with a wick mounted on a housing including a heated mat, Figure 2 is a section on the line B-B of Figure 1, Figure 3 is a view beneath of the container on the line A-A of Figure 1, Figure 4 is a schematic cross-section of part of the air freshener of Figures 1 to 3 showing schematically an electrical connection between a connection wire of the freshener and the mat of the air freshener, Figure 5 is a schematic cross sectional view with an alternative form of the air freshener of Figures I to 4 with two fragrance containers, certain parts shown in Figures 1 to 4 being omitted for clarity, Figure 6 is a side elevation of a second form of air freshener showing a wick surrounded by a conductive fibre mat and including conducting connectors, and Figure 7 is a plan view from above of the air freshener of Figure 6. A voltage is applied to one of the connectors and a return to the other connector 55 to complete a circuit through the mat.

Figure 8 is a side elevation, partly in section, of a third form of air freshener showing a fragrance container with a wick, and a housing including a heated mat and a latch, the latch being in an unlatched configuration, Figure 9 is a side elevation, partly in section, of the air freshener of Figure 8, the latch being in a latched configuration, and Figure 10 is a diagram of a drive circuit for any one of the forms of air freshener shown in Figures 1 to 9. The heated mat is represented by resistor RI, and is powered through capacitor Cl from mains electricity. A shunt circuit is formed by load resistor R2 and two diode networks. The first network is formed from diode DI and zener diode Zi, connected to limit voltage excursions on one polarity of the alternating waveform. The second network is formed from diode D2 and zener diode Z2 which limits voltage excursions on the other polarity of the alternating waveform.

Referring first to Figures 1 to 4, the air freshener includes a fragrance container 10 including a wick 11. The container 10 is mounted on a housing 12, in a manner to be described below, with the housing 12 including a heated mat 13.

The container 10 is formed from any suitable material such as glass or plastics and has a fragrancecontajnjng chamber leading to a neck 14 terminating in an outlet 15. The outlet 15 is surrounded by a flange 16. The wick 11, which may be formed from any suitable known wicking material, is held in the neck 14 and has a first end and a second end. The wick 11 depends downwardly so that the first end is in the fragrance 17, which may be of any known kind. The wick 11 may have a diameter of from 3mm to 13mm. The second end extends through the neck and terminates at the open end of the outlet 15. The second end of the wick 11 has a surface which is substantially flush with the outlet 15.

The housing 12, which may be formed from any suitable material, such as a plastics material, includes a generally rectangular open holder 18 formed by an outer part 19 and an inner part 20 which are a snap fit together. The outer part has a rectangular outer wall 21 from which extend, along two opposed portions of the outer wall 21, respective inwardly extending flanges 22 that end in respective lips 23. The inner part has an outer wall 24 that fits within the outer wall 21 of the outer part 19. The outer wall 24 of the inner part 20 leads to a base 25 provided with a central circular aperture 26 from which projects a plurality of inwardly directed radial fingers 27. The purpose of these fingers 27 will be described below.

The mat 13 sits on the base 25 and is formed of a woven material having warp and weft with conductive fibres in the warp andlor weft. The fibre is coated with metal or carbon or other conductive material, or has conductive materials incorporated into the fibre. The resistance of the carbon fibres is preferably such that the resistance of the mat 13 is between 0.4 to 4000 Ohms. The mat 13 is in the form of a planar sheet and is overlaid by a support grille 29.

Alternatively the rectilinear mat 13 is formed of electrically conductive carbon fibres interwoven with non-conductive fibres. The carbon fibres prefereably have a weight of between I 7g/m sq to 200g/m sq. The fibres can be PAN (polyacrylonitrile) based carbon fibres with a fibre length of between 6mm and 12mm and a fibre diameter of, for example, 6.8 microns. The carbon fibres can be bound together by 10% of PVA.

The mat 13 may be between 0.2 and 2.5 mm thick and can be a wet-form nonwoven mat of fibres made by a process similar to papermaking.

To one side of the outer part 19, the housing 12 is provided with three pins, two of which are shown at 31, for insertion into a conventional electrical socket. The live and neutral pins 31 are connected to respective resistance wires 32, 33.. The resistance wires are located adjacent respective opposing parallel edges of the rectilinear mat 13 and extend over the surface beneath respective flanges 22 on the outer part 19. These flanges 22 press the associated wires 32, 33 into physical and electrical contact with the carbon fibre mat 13.

The assembly of the wires is shown in more detail in Figure 4.

The container 10 is connected to the housing 12 by pushing the flange 16 on the neck 14 of the container 10 past the fingers 27. The fingers 27 then close behind the flange 16 to support the container 10 on the housing 12. The effect of this is to push an end surface of the second end of the wick 11 into contact with the mat 13.

In use, a container 10 of fragrance 17 is mounted on the housing 12 as described above. Prior to such mounting, the outlet 15 may be closed by a simple foil seal (not shown), which is attached by, for example, adhesive or welding means. Since there is no space between such foil seal and the wick, there is no possibility of fragrance accumulating in this area so that there is no spillage of fragrance 17 when the foil is removed, prior to insertion of the neck 14 into the housing 12.

The connector 30 is then plugged into a power socket (not shown) which is switched on. Power then passes through the wires 32, 33 which in turn supply power to the mat 13.

At the same time, fragrance 17 passes up the first wick 11 and then wicks into the mat 13 so that the mat 13 forms a second heated wick. The arrangement is such that the mat 13 heats to a temperature sufficient to evaporate the fragrance 17 supplied to the mat 13 by the wick 11. The gaps between the fingers 27 form an air path through the housing to allow an upward flow of air through the mat 13 and the grille 29 so conveying evaporated fragrance to the surrounding atmosphere. Since the fragrance 17 is wicked directly to and over the mat 13 and the evaporative area of the mat 13 is much greater than the evaporative area of the wick 11, the power required to produce satisfactory fragrance dispersion may be low since almost all the thermal energy is used to heat the liquid. In one example, 1W energy dissipation over a 150mm2 area of mat 13 may be sufficient. The carbon fibres heat up very quickly and cool down equally quickly so providing a very quick response. In addition, the wires 32, 33 may be formed from a material whose resistance increases with temperature. Accordingly, the mat 13 may initially heat up relatively quickly due to the low resistance of the wires 32, 33 but may then reach a point of equilibrium as the resistance of the wires 32, 33 increases. This self regulation minimises any risk of fire through overheating.

The container 10 has no protruding wick making it difficult for children to ingest the liquid and this is a safety feature. Also, it is easy to align the container 10 into the housing 12 without a protruding wick. There is no need for any special cap to cover the first wick 11 so reducing manufacturing costs and little or no loss of liquid when the foil is removed. When the fragrance 27 has all been evaporated it is a simple matter to remove the container 10 and replace it with a fresh container 10, after first 1 0 having removed the foil.

Referring next to Figure 5, in a modification, two containers 40, 41 are provided each with a respective wick 42, 43. The wicks 42, 43 contact a single conductive mat 44 of the kind described above with reference to Figures 1 to 4.

In this arrangement, the mat 44 is divided into two areas each overlying a respective wick, 42, and 43. The areas are separately heatable via a common resistance wire and two selectively positive resistance wires and control means (not shown) may be provided to control which area is heated. For example, the areas may be heated alternately. Alternatively or additionally, they may both be heated together to provide a fragrance caused by a combination of the fragrances in containers 40, 41. The mat 44 may incorporate a barrier 55 of, for example, wax separating the two areas and preventing the combining of the fragrances prior to heating.

Referring next to Figures 6 and 7, the second form of air freshener includes a container 50 including a wick 51. The container 50 has a chamber for containing fragrance connected to a neck 52. A wick 51, formed of any known suitable wicking material, extends from the chamber through the neck. Within the neck, a carbon fibre mat 54 is wrapped substantially but not continuously around the wick 51. The mat 54 may be formed as described above with reference to Figures 1 to 4. A pair of L- shaped conducting connectors extends between the ends of the mat 54 and the inner surface of the neck 52 and then extends over the annular end surface 56 of the neck 52.

In use, the end of the neck 52 is covered by protective foil (not shown). The foil is removed and the container 50 connected to a housing providing a supply of power to the conducting connectors 55. This power heats the mat 54 to evaporate fragrance from the wick 53.

As in the embodiment described above with reference to Figures 1 to 4, the mat 54 heats and cools very quickly so making the air dispenser very responsive. The amount of power needed is low since the thermal mass of the mat 54 is low. The container 50 being made typically of glass or plastic is a poor thermal conductor so most of the thermal energy is directed towards and absorbed by the wick 51. in addition, some fragrance will wick from the wick 53 into the mat 54 and be evaporated directly off the mat 54 so also increasing the efficiency of the transfer of heat to the fragrance.

Referring next to the embodiment of Figure 8, the parts common to Figure 1 and Figure 8 are given the same reference numerals and will not be described in detail. In the embodiment of Figures 8, one of the resistance wires 32, 33 is replaced by a V- shaped connector 60. The V-shaped connector 60 has first and second limbs 60a, 60b.

The first limb 60a provides a permanent electrical connection with the mat and the second limb 60b has a free end adjacent to, but spaced from, an inner end of one of the connector pins 31 (See Figure 9).

A switch is formed by a slider 59, which is carried by a mounting. The mounting is formed by a wall 61 depending from a front face 62 of the housing 12 from which project the connector pins 31. The waIl 61 is formed with a central aperture into which projects a flexible limb 63. The flexible limb 63 has a free end provided with a projection 64. The end of the wall 61 remote from the pins 31 is formed with a stop face 65 extending normal to the wall 61 and beneath the mat 13.

The slider 59 is an elongate member having a first end adjacent the free end of the limb 60b of the connector and an opposite end engaging a tension spring 67 acting between stop face 65 and the slider 59 and tending to urge the slider 59 towards the stop face 65. The slider 59 is located adjacent a rear face of the wall 61 and includes, adjacent a second end, an aperture 68 that receives the projection 64 of the flexible limb 63 to hold the slider 59 in the inoperative position shown in Figure 9.

In use, the flange 16 on the neck 14 of the fragrance container 10 is moved towards aperture 26 in the housing 31. At the same time a protrusion 56 on the container 10 engages the projection 64 located in the aperture 68 in the slider 59 from the opposite 1 5 side of the slider 59, thereby displacing the projection 64 from the aperture 68. The slider 59 is then moved towards the connector pins 31, against the tension spring 67 on continued insertion of the flange 16 into the aperture 26. This movement of the slider 59 moves the limb 60b into electrical contact with the connector pin 31, as shown in Figure 8. Thus power is supplied to the mat. The force required on the slider 59 to cause power to be supplied to the mat 13 and to maintain the supply of power is greater than the tension in the tension spring 67. The force is maintained by the fingers 27 on the flange 16.

In this form of air freshener, the grille of Figure 2 is replaced with an extended housing and a grille 61 mounted on the extended housing. In this form of air freshener, the user is thus prevented from touching the mat 13 when power is supplied to the mat 13. This advantageously allows higher voltages to be safely used across the mat 13. This form also prevents the user from causing power to be supplied to the mat 13 by merely depressing the projection 64 with, for example, the user's finger.

On removal of the container 10 from the aperture 26, the slider 59 moves downwardly and the resilience of the limb 60b thereby disconnects the mat 13 from the power supply. This downward movement continues assisted by the action of the tension spring 67 until the projection 64 on the limb 63 is in register with the aperture 68 in the slider. The projection 64 then enters the aperture 68 to hold the slider 59 in the retracted position. Thus, by including the tension spring 67, the slider will naturally reset itself when the container 10 is removed. Only when a container is in place will the slider be held against the wire limb 60b.

Figure 10 shows a drive circuit in the form of shunt circuit connected to an AC mains power supply. The circuit comprises a capacitor Cl connected on one side to the power supply and on the other side to a resistor Ri. The resistor RI represents mat 13 and is connected in parallel to an arrangement of a second resistor R2, first and second diodes Dl, D2 and first and second zener diodes ZI, Z2. The first and second diodes Dl, D2 are respectively connected in series to the first and second zener diodes Z 1, Z2, which respectively have first and second breakdown voltages. The resistor R2 is connected in series to the first diode Dl, which prevents current flow through the resistor R2 in a one direction corresponding to a positive voltage cycle and the first zener diode prevents current flow in the other direction corresponding to a negative voltage cycle unless the voltage across the first zener diode exceeds the first breakdown voltage The first diode Dl and first zener diode Zi are connected in parallel to the second diode D2 and the second zener diode Z2 and the second diode D2 prevents current flow in the other direction though the resistor R2 and the second zener diode Z2 prevents current flow in the one direction unless the voltage across the second zener diode Z2 exceeds the second breakdown voltage.

If the voltage across RI is higher than desired, the temperature of resistor Rl may become too high. Too much fragrance may therefore be evaporated and the fragrance may be chemically degraded. If the voltage across the voltage is too low, not enough fragrance will be evaporated.

Capacitor Cl serves to reduce in a conventional way the voltage across the resistor RI. Thus, the temperature of the resistor RI can be regulated by selecting a capacitor of a particular capacitance Voltage across resistor RI may still exceed the desired voltage due to fluctuations in the main voltage and fluctuations in the capacitance of capacitor Cl. The arrangement 1 0 of resistor R2, first and second diodes Dl, D2 and first and second zener diodes Z I, Z2 prevents this. If the voltage across resistor Ri, and therefore across the arrangement, during the positive or negative voltage cycles exceeds a predetermined minimum voltage such that the breakdown voltage of the respective zener diode Zl, Z2 is exceeded, then current flows through diode Dl and zener diode ZI and through diode D2 and zener diode Z2 respectively for negative and positive voltage cycles.

The combined resistance of the arrangement and of resistor Ri is therefore reduced.

This results in a reduction in voltage across resistor RI and therefore a reduction in temperature of the mat.

Capacitor Cl, resistor R2 and the zener diodes Zi, Z2 are chosen according to the desired temperature of operation of the mat 13, the likely voltage fluctuation across the resistor Ri and the desired rate of evaporation of the fragrance. They are also chosen to maintain the mat 13 at the desired operating temperature and so that the maximum desired operated temperature is not exceeded. The combination of resistor R2 and zener diodes Zl, Z2 are also chosen so that the neither of the zener diodes overheats. If the resistor R2 has a low resistance, more current will flow through the zener diodes when the predetermined minimum voltage is exceeded, leading to greater reduction in current flowing through resistor RI, but requiring higher power zener diodes or a heat sink or both. If the resistor R2 has a high resistance, lower power zener diodes are required, but when the predetermined minimum voltage across the zener diode is exceeded, the reduction in power across the resistor Ri will be less.

Accordingly, the combination of zener diodes ZI, Z2 and resistor R2 is chosen so that the resistance of resistor RI is effective in reducing the voltage across resistor RI, while the respective powers of zener diodes ZI, Z2 are chosen to be a minimum taking into consideration this resistance.

It will be appreciated that there are a number of variations that can be made to the embodiments described above with reference to the drawings. In the embodiment of Figures 1 to 4, the container 10 and the housing 12 need not be separable; they could be inseparable or formed with one piece so that they are disposed of together. In this case, the connector 30 may be separate from the housing and connected to the housing by cable. The mat 28 of Figures 1 to 4 need not be supplied with power through the wires 32, 33; the power could be supplied in any convenient way.

In addition, the power to the wires 32, 33 may be controlled by a control system that allows the user to vary the power and so vary the fragrance intensity. The control system may also allow the power to the mat 13 to be cycled so providing the fragrance with on/off periods. The control system could also allow a boost function that increases the power to the mat 13 for short periods of time to boost the evaporation of fragrance. Where the container 10 and the housing 12 are inseparable, the first wick 11 and the mat 13 may be formed in one piece.

The mat 13 need not be supported by the holder 18; the mat 13 could be self- supporting. The grille 29 is optional.

The mat 13 need not be formed as described above with reference to the drawings.

The mat 13 could be formed from woven fibres. It is not necessary for all the fibres to be carbon fibres - other conductive fibres can be used. Nonconductive fibres coated or plated with a conductive material, for example, silver or nickel may also be used.

The mat can also be formed from a woven or non-woven material that is made electrically conductive by silver or nickel coating or plating after being formed. A woven mat can be woven from a small number of fibres including a single fibre of one continuous length or a large number.

In the embodiment of Figures 6 and 7, the carbon fibre mat wrapped around the wick 51 can be continuous around the wick 51. In all embodiments, the length of the resistance wires can be used to control the power supplied to the mat. The wires have a resistance and the length of wire through which a current must pass for the mat to be heated can be controlled. This length of wire through which current passes can be controlled by controlling the length of wire in contact with the mat.

The live and neutral pins 31 connected to the power supply and connected to respective resistance wires 32, 33 may have an additional currentlimiting fuse connected in series.

Instead of the drive circuit being connected to a mains power supply, it can be connected to a disposable or rechargeable battery. A conventional transformer could be used to reduce the voltage across the mat 13, rather than a capacitor. Resistor R2 can be a variable resistor. This might in particular be useful if it is desired for the mat to be at different temperatures of operation corresponding to fragrances with different rates of evaporation. Instead of a zener diode, other type of voltage breakdown diode can be used.

Although the embodiments described above with reference to the drawings are fragrance dispensers, the same structures could be used for evaporating other liquids such as insecticides.

Claims

cLAIMS I. A wick assembly for evaporating a liquid comprising a wick for

conveying a liquid from a source and a heater for heating and evaporating liquid from the wick, the heater being formed from a fibrous material including conductive fibres.
2. An assembly according to claim 1 wherein the fibrous material is woven using one or more continuous lengths of fibre.
3. An assembly according to claim 2 wherein the resistance of the mat is between 0.4 and 4000 Ohms.
4. An assembly according to claim 3 wherein the conductive fibres are formed from non-conductive fibres coated or plated with a conductive material
5. An assembly according to claim 3 wherein the mat is formed from carbon fibres
6. An assembly according to claim 5 wherein the carbon fibres have a weight of from I 7g/m2 to 200g/m2
7. An assembly according to claim 6 wherein the carbon fibres have lengths of from 6mm to 12mm.
8. An assembly according to any one of claims 3 to 7 wherein the mat is formed from a laid web of fibres held together by a binder.
9. An assembly according to any one of claims I to 8 wherein the wick has a first end and a second end, the first end being for immersion in the liquid to wick the liquid from said first end to said second end, the second end contacting the mat to allow said fluid to wick into the mat.
10. An assembly according to claim 9 wherein the second end of the wick has an end surface and the mat is formed as a planar sheet, a surface of said planar sheet contacting the end surface of the second end of the wick.
11. An assembly according to claim 10 wherein said mat is held in a housing.
12. An assembly according to claim 11 wherein the housing includes means for supplying power to the mat.
13.An assembly according to claim 12 wherein said power supply means include conductive elements.
14. An assembly according to claim 13 wherein said conductive elements include a pair of spaced conductive wires, each conductive wire contacting the mat for supplying power to the mat.
1 5. An assembly according to claim 14 wherein the housing includes members pressing the wires into electrical contact with the mat.
16.An assembly according to claim 14 or 15 wherein the wires are formed from a conductive material having a resistance that increases with temperature.
1 7. An assembly according to any one of claims II to 16 wherein the housing defines an air flow path across and/or through the mat.
18.An assembly according to any one of claims 12 to 17 in combination with at least one container for a liquid, the wick being carried by the container and the container being connected to the housing.
19. The assembly according to claim 18 wherein the container for said liquid has an edge defining an opening, the second end of the wick being located at said opening with the end of the wick being flush with the edge.
20. An assembly according to one of claims 18 or 19 wherein the container and the wick are separable from the housing to aid replacement of the container and the wick.
21. The assembly according to claim 19 further comprising a replacement container which, before connection to said housing, is closed by a seal over said opening, the seal being flush with the end of the wick.
22. An assembly according to one of claims 20 or 21 wherein the housing includes a releasable connector for connecting the housing to the container.
23. An assembly according to claim 22 wherein the housing includes an aperture formed with radially inwardly directed fingers, the container having a neck insertable through the fingers to allow the fingers to engage behind a flange on the neck to connect the container to the housing.
24.An assembly according to any one of claims 18 to 23 wherein two containers are provided, each container having a respective wick contacting said mat.
25. An assembly according to claim 24 wherein the mat has two or more areas, each area being in contact with a respective wick and each area being separately selectively heatable.
26. An assembly according to claim 25 wherein each area is separated from each other area by a barrier.
27. An assembly according to claim 26 wherein the barrier is made of wax.

1 0
28. An assembly according to claim 2 wherein the wick has a first end and a second end, the first end being for immersion in the liquid to wick the liquid from said first end to said second end, the mat being wrapped substantially around the second end.
29.An assembly according to claim 28 in combination with a container for said liquid having a neck, the second end of the wick being located in said neck and the mat being located between the wick end and the neck.
30.An assembly according to claim 29 and including a pair of electrical conductors connecting electrically with the mat and having respective ends remote from the mat for connection to a source of electrical power.
3 1. An assembly according to any one of claims 18 to 30 and including a device to prevent the supply of power to the mat when the at least one container is not correctly inserted.
32. An assembly according to claim 31 wherein said device is a switch.
33. An assembly according to claim 32 wherein said switch is operated on connection of the at least one container to the housing.
34.An assembly according to one of claims 32 or 33 wherein said switch includes a connector having two limbs, one limb having a permanent electrical connection with the mat and the other limb having an end which in a first position is not in electrical connection with the power supply and which, on connection of the at least one container to the housing, is caused to move to a second position in electrical connection with the power supply.
35. An assembly according to any preceding claim including means to prevent the temperature of the heater exceeding a predetermined temperature.
36. An assembly according to claim 35 wherein the heater has a voltage iS thereacross and the means includes a capacitor connected in series to the heater to reduce the voltage across the heater.
37. An assembly according to one of claims 35 or 36 wherein the means includes an arrangement connected in parallel to the heater, the arrangement comprising a resistor, a first diode, a second diode, a first zener diode and a second zener diode, the first and second diode being respectively connected in series to the first and second zener diodes, the first and second zener diodes respectively having first and second breakdown voltages, the resistor being connected in series to the first diode, the first diode preventing current flow in one direction through the resistor and the first zener diode preventing current flow in the other direction unless a voltage across the zener diode exceeds the first breakdown voltage, and the first diode and first zener diode being connected in parallel to the second diode and the second zener diode, the second diode preventing current flow in the other direction though the resistor and the second zener diode preventing current flow in the one direction unless a voltage across the second zener diode exceeds the second breakdown voltage.
38. An assembly substantially as hereinbefore described with reference to Figures 1 to 4 or to Figure 5 or to Figures 6 and 7 or to Figures 8 and 9 or to Figure 10 of the accompanying drawings.
39. An air freshener incorporating a wick assembly according to any one of claims 1 to 37.
40. A vapour dispenser incorporating a wick assembly according to any one of claims I to 37.
41. An insecticide dispenser incorporating a wick assembly according to any one of claims Ito 37.