Liquid heaters and vaporizers – Wick
Reexamination Certificate
2000-12-18
2002-09-10
Wilson, Gregory (Department: 3749)
Liquid heaters and vaporizers
Wick
C261SDIG001, C392S392000, C392S395000, C043S129000
Reexamination Certificate
active
06446583
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a device for evaporating volatile substances, in particular insecticides and/or aromatics.
Insecticide and aromatic evaporation devices are generally known. For example, evaporation devices are known where a small plate introduced into an evaporation device and impregnated with an active ingredient is heated in order to evaporate the active ingredient. Furthermore a method is also known by which a container containing a volatile substance is introduced into a housing of an evaporation device. This container comprises a wick that conveys the substance to be evaporated by means of capillary action out of the container, whereby the wick end protruding from the container is located next to a heating element such as a ceramic block The substance is evaporated through the heat radiated by the ceramic block and can escape from the housing into the environment through aeration slits in the housing.
A disadvantage with the prior evaporation devices is that it is not possible to adapt the degree of evaporation to the prevailing room conditions or to the different sensitivities of persons present in the room. Thus, for example, in smaller rooms with insufficient air ventilation, it is desirable to lower the degree of evaporation, and this is not possible with prior evaporation devices. Furthermore adjustability of evaporation is especially desirable for insecticides, so that the degree of evaporation can be adjusted in accordance with the sensitivity of persons present in the room. This has also not been possible with the prior devices.
In order to be able to adjust the degree of evaporation to the appliwire requirements it is known to control the degree of evaporation by adjusting the heating output. Evaporation devices of that type are relatively expensive to manufacture, and are prone to malfunctions.
It is known in prior evaporation devices that the relative distance between the heating element and wick can be changed to adjust the degree of evaporation while the heating output is maintained constant (EP 0 943 344 A1). The evaporation device includes a resistance heating element with a connecting plug that is threaded into a housing element in which a container of the substances to be evaporated is located. Pin openings are provided on the housing element into which locking pins are inserted in such manner that they mesh with the threads of the plug. The distance between the resistance-heating element and a wick end protruding from the container can be changed by twisting the plug element. The plug element can be mounted eccentrically in the housing element, so that it too can be used to change the relative distance between the wick end and the resistance heating element to achieve the desired degree of evaporation. However, this method of adjusting the degree of evaporation is relatively complicated in construction and expensive to manufacture.
Another type of evaporation device in which the heating output remains constant and the relative distance between the wick and the heating element can be adjusted is known from WO 98/19526. The evaporation device comprises a housing into which a container with a wick can be screwed. The container is connected via a bushing to a swivel arm that moves in a guide slot, extending radially at an angle to the horizontal in the housing wall. Through the coupling of the swivel arm to the container the container is lifted relative to the housing in the axial direction when the swivel arm is turned radially. The wick end protruding form the container may be shifted relative to the fixed heating element. On the whole, this is a relatively expensive and complicated construction with a great number of additional components, so that the evaporating device is also expensive to manufacture.
It is therefore an object of the invention to provide an evaporation device for volatile substances, in particular insecticides and/or aromatics, which is simple in structure and can be produced economically yet the degree of evaporation can be easily adjusted to meet current requirements.
The above object is accomplished according to the present invention by providing a heating element carried on a movable heater assembly mounted in the housing. The heating element may be displaced longitudinally relative to the wick axis and can be fixed in different longitudinal positions relative to the wick end for the adjustment of the degree of evaporation. The heating element is advantageously designed as having simultaneously a double function by serving as a heating element and as a movable heater assembly so that the degree of evaporation can easily be adjusted by displacing the assembly in the longitudinal direction along the wick axis. In addition, this integration of functions makes it possible to achieve an overall space-saving and compact structure without significant expenditure for components and material. The already present components are used to adjust the degree of evaporation. An evaporation device of this type is especially well suited for small installation situations. The degree of evaporation can be adapted individually and easily to the appliwire requirements, and in addition the operation is simple and functioning is reliable.
In principle, several possibilities exist for mounting the heating element on the movable heater assembly capable of longitudinal displacement in the direction of the wick axis. In a preferred embodiment the heating element can be fixed on the housing by means of a clamp connection and/or a locking connection snapped. In another preferred embodiment, the movable heater assembly is fixed in a longitudinal position of the wick by means of a snap-in locking connection. The snap-in locking connection provides a secure holding within a given adjustment range. The greatest possible reliability of function is achieved in the sense that on the one hand the degree of evaporation can be adjusted continuously if necessary by simply pressing down the locking connection while on the other hand assurance is provided that the movable heater assembly is held securely in the desired position.
In a preferred embodiment the movable heater assembly is provided with at least one guide arm extending generally perpendicular to the wick axis. The arm is installed with one end of the guide arm in a slot opening in the housing wall for access from the outside of the housing. The guide arm can be made economically without significant expenditure on the movable heater assembly. In addition, the guide arm can serve as an indicator of the currently set distance between the heating element and the wick end by its position in the slot opening, possibly in combination with a scale on the housing area surrounding the slot opening. The guide arm is easily accessible on the other side through such a slot opening for easy maintenance.
At least one guide arm may be used advantageously, held in the slot opening between two end stop positions in the housing wall. To provide an advantageous targeted and controlled guiding of the movable heater assembly, the guiding device may be provided with two guide arms connectable to opposing housing sides. The reliability of function of the movable heater assembly is further enhanced.
The linear guide device preferably has a first guide element on each guide arm approximately parallel to the longitudinal direction of the wick axis. There is a second guide element on the housing corresponding to each first guide element. The first guide element may be in the form of a guide groove and the second guide element in the form of a guide ridge which slides in the guide groove, or vice-versa. To ensure especially simple and reliable positioning, and at the same time simple displacement, the guide ridge may be guided with a friction lock in the guide groove. Advantageously, snap-in openings may be made on the guide ridge, spaced to correspond to different longitudinal distance settings. A snap-in protrusion of the movable heater assembly may be snapped into the opening at a given distan
C.T.R. Consultoria Técnica e Representacöes Lda
Flint Cort
McNair Law Firm, P.A.
Wilson Gregory
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