WO2011058290A1

WO2011058290A1 - A two phase evaporator

Info

Publication number: WO2011058290A1
Application number: PCT/GB2009/002668
Authority: WO
Inventors: Adrian Blagg; Sue Wigley
Original assignee: Reckitt & Colman (Overseas) Limited
Priority date: 2009-11-16
Filing date: 2009-11-16
Publication date: 2011-05-19

Abstract

A two phase evaporator comprising a vessel containing two immiscible liquids, a first of which forms an upper layer and a second of which forms a lower layer, a stopper closing the top of the vessel, and two wicks extending through the stopper and into the liquids, wherein one of the wicks has a liquid impermeable cladding along the portion which, in use, comes into contact with the first liquid, and wherein a key is provided between the stopper and the vessel to ensure that the wicks are correctly orientated within the vessel.

Description

A TWO PHASE EVAPORATOR

The present invention relates to a two phase evaporator comprising a vessel containing two immiscible liquids, a first of which forms an upper layer and a second of which forms a lower layer, a stopper closing the top of the vessel, and two wicks extending through the stopper and into the liquids, wherein one of the wicks has a liquid

impermeable cladding along the portion which, in use, comes into contact with the first liquid. Such an evaporator will subsequently be referred to as "of the kind described" .

An evaporator of the kind described has recently been proposed in US 7055764. Here the wick with the impermeable cladding is only in direct contact with the lower layer of liquid and therefore only disperses this liquid. The other wick may be in contact with both layers, but cannot emit liquid from the lower layer as this is blocked by the upper layer which saturates the wick. The evaporator is therefore able to emit the liquids separately.

The evaporator may simply be designed to operate at ambient temperature. However, an important application of the evaporator is as a refill for a device which is provided with a heater positioned adjacent to the external wall of the evaporator. Under such circumstances, if the wicks are incorrectly aligned with respect to the heater, preferential heating of one of the two wicks occurs resulting in faster evaporation from the preferentially heated wick using up this liquid more quickly than intended. As a consequence, the evaporator will dispense only a single liquid in the later part of its life thereby inhibiting its performance. According to the present invention, in an evaporator of the kind described a key is provided between the stopper and the vessel to ensure that the wicks are correctly orientated within the vessel.

This ensures that the wicks are always in the correct alignment. Thus, when a heater is used, this will heat the wicks and hence disperse the liquids at the desired rate.

It may be desirable to dispense the liquid at a faster rate than the other, in which case the wicks may be

orientated such that one is closer to the vessel wall than the other. However, it is generally desirable to dispense the two liquids at the same rate such that the two wicks are preferably substantially equidistant from the wall of the vessel which, in use, will face a heater.

The key may be in the form of a lug projecting from the vessel which engages with the groove in the stopper.

However, preferably, the key is provided by a lug on the stopper which engages with a groove in the vessel.

There may be a single key or an asymmetric arrangement of multiple keys allowing insertion of the stopper in only a single orientation. However, there may be two keys having the same configuration and being diametrically opposed to one another allowing insertion of the stopper in two

different orientations either one of which provides the correct orientation within the vessel. The groove or grooves on the vessel may be provided inside of the neck of the vessel. However, they are

preferably provided on the outside of the neck of the vessel so as not to interfere with the sealing engagement between the stopper and the vessel.

The evaporator is preferably provided with a removable screw threaded lid which will prevent evaporation of the liquid during storage and transportation. In this case, if the stopper is provided with lugs which fit in grooves on the outside of the neck of the bottle, the lugs are

preferably provided with screw threaded portions in

alignment with a screw thread on the outside of the neck of the bottle which are complimentary to a female screw thread in the removable lid.

The liquids are preferably both fragrances which are chosen to complement one another. However, other liquids such as pesticides, malodour counteractants , or insect repellents may also be dispensed.

An example of an evaporator in accordance with the present invention will now be described with reference to the accompanying drawings, in which:

Fig. 1 is a schematic cross-section through the

evaporator;

Fig. 2 is a top view of the vessel without the stopper; Fig. 3 is a top view of the stopper;

Fig. 4 is a front view of the vessel without the stopper; and

Fig. 5 is a front view of the stopper and wicks. The evaporator is primarily intended as a refill for an electrical plug-in device having a heating element. Such a device is sold, for example, under the Airwick (RTM) brand.

The basic principle of a two wick evaporator is shown in Fig. 1. The vessel 1 which is preferably made of glass is closed by a plastic stopper 2. The stopper 2 is provided with a pair of openings through which first 3 and second 4 wicks protrude. The wicks extend to a position adjacent to the bottom of the vessel 1. Wick 4 is surrounded by liquid impermeable cladding along its length such that liquid can only enter the second wick 4 at its bottom end. In the vessel are two immiscible liquids forming an upper layer 6 and a lower layer 7. The upper layer 6 will generally have an organic base while the lower layer 7 will be water based. As can be seen from Fig. 1, the first wick 3 passes through both liquid layers. It cannot, however, wick the more dense second layer 7 as this is obstructed by the dense upper layer 6 which will be emitted by wick 3. On the other hand, the second wick 4 will only come into contact with the more dense second layer 7 and will emit only this liquid. It will be appreciated that this

relationship is preserved as the liquid level drops and, provided that the wicks extend close to the bottom of the vessel it will last, to all intents and purposes, for the lifetime of the evaporator. As shown in Fig. 2, when the evaporator is used in a device with a heater, heat is applied to the vessel 1 in the direction shown by arrow 8. In order to ensure that the wicks 3, 4 are correctly aligned with respect to the heat source, the stopper 2 is provided with a pair of lugs 9 which fit into complementary grooves 10 in the outer wall of the neck of the vessel. The stopper 2 has a downwardly depending skirt 11 radially inwardly of the lugs 9 as shown in Fig. 5 which fits within the neck of the vessel to provide a seal. As will be seen in Fig. 4, the vessel has a male screw thread 12 to receive a cap (not shown) with a complementary female screw thread to prevent evaporation of the liquid during transportation and storage. As the groove 10 extends across the screw thread 12, the lug 9 is also provided with a screw thread portion 13 which, with the stopper 2 in place is continuous with the screw thread 12. This also helps to retain the stopper firmly within the vessel when the cap is in place as the cap bears against the screw thread portion 13 to provide a closing force on the stopper. As can be seen from Figs. 2 and 3, it is possible to insert the stopper in one of two orientations off-set by 180° from one another. However, it will be appreciated that either of these orientations will ensure that the wicks 3, 4 remain equidistant from the heat source 8.

Claims

CLAIMS : -

1. A two phase evaporator comprising a vessel containing two immiscible liquids, a first of which forms an upper layer and a second of which forms a lower layer, a stopper closing the top of the vessel, and two wicks extending through the stopper and into the liquids, wherein one of the wicks has a liquid impermeable cladding along the portion which, in use, comes into contact with the first liquid, and wherein a key is provided between the stopper and the vessel to ensure that the wicks are correctly orientated within the vessel .

2. An evaporator according to claim 1, wherein the two wicks are substantially equidistant from the wall of the vessel which, in use, will face a heater.

3. An evaporator according to claim 1 or claim 2, wherein the key is provided by a lug on the stopper which engages with a groove in the vessel.

4: An evaporator according to claim 3, wherein the groove is on the outside of the neck of the vessel. 5. An evaporator according to claims 3 and 4, wherein the outside of the neck of the vessel has a male screw thread, and the lug has a male screw threaded portion in alignment with the male screw thread.