Claims:
1. An electrically heated vaporizer comprising
2. a base having means for connection to an electrical power supply, the base including
3. an annular container and having an upper end and a lower end removably mounted on the base, the container having an inner and an outer wall defining therebetween a closed interior annular chamber extending substantially the length of the container,
4. The vaporizer of claim 1, wherein the connection means comprises a plug-in connection capable of being connected to the electrical power
5. The vaporizer of claim 1, further comprising a control circuit connecting the heating means to the connection means for controlling the temperature of the heat generated by the heating means, the control
6. The vaporizer of claim 3, wherein the heating means comprises two electrical resistance heating elements connected in parallel to each other
7. The vaporizer of claim 4, wherein the heating elements are capable of consuming a maximum power of 10 watts in dependence on the setting of the
8. The vaporizer of claim 3, wherein the rheostat is arranged in the lower portion of the base and further comprising a rotary pin affixed to the rheostat and extending therefrom through the upper portion of the base to the rotary member, the rotary pin being coupled to the rotary member for
9. The vaporizer of claim 6, further comprising a highly heat-conducting duct mounted in the enclosed housing of the base, the duct comprising an umbrella-shaped portion covering the heating means and a tubular portion extending from the umbrella-shaped portion into the upper portion of the
10. The vaporizer of claim 3, wherein the rheostat is arranged in the lower portion of the base and comprises an ON/OFF switch, and further comprising a rotary pin affixed to the rheostat for adjusting the rheostat between positions of increased and reduced resistance, the rotary pin extending from the rheostat through the upper portion of the base to the rotary member, the rotary pin being coupled to the rotary member for rotation therewith and corresponding adjustment of the rheostat between said positions, and the switch being arranged to assume its OFF position when the rheostat has been adjusted to the position of greatest resistance and its ON position when the rheostat is rotated in the direction of reduced
11. The vaporizer of claim 8, wherein the lower portion of the base is transparent and further comprising a glow discharge lamp and a barrier resistance arranged in the transparent lower base portion, the glow discharge lamp and barrier resistance being connected in series to the
12. The vaporizer of claim 8, wherein the lower portion of the base is transparent and further comprising a glow discharge lamp and a barrier resistance arranged in the transparent lower base portion, the glow discharge lamp and barrier resistance being connected in series to the electrical power supply and to a connecting line between the rheostat and
13. The vaporizer of claim 1, wherein the lower portion of the base is transparent and further comprising a light source arranged in the transparent lower base portion and connected to the electrical power
14. The vaporizer of claim 11, wherein the light source is a glow discharge lamp and further comprising a barrier resistance connected in series with
15. The vaporizer of claim 11, further comprising a heat-insulating wall
16. The vaporizer of claim 1, further comprising a control circuit connecting the heating means to the connection means for controlling the temperature of the heat generated by the heating means, the control circuit comprising a rheostat, and a copper alloy duct mounted in the enclosed housing of the base, the duct comprising an umbrella-shaped portion covering the heating means and a tubular portion extending from
17. The vaporizer of claim 1, further comprising an outer ring surrounding the lower portion of the base and defining a gap with the lower base portion, the gap being arranged to receive the lower end of the annular
18. The vaporizer of claim 15, further comprising a skirt projecting from
19. The vaporizer of claim 1, wherein the inner wall of the container contacts the upper portion of the base for good heat transfer
20. The vaporizer of claim 1, wherein the annular carrier means consists of a pluralaty of rings of a porous synthetic resin material soaked in the
21. The vaporizer of claim 1, wherein the annular carrier means consists of a plurality of rings of a cellulosic material soaked in the substance to
22. The vaporizer of claim 1, wherein the annular carrier means consists of a plurality of rings of a porous mineral material soaked in the substance
23. The vaporizer of claim 1, wherein the annular carrier means consists of
24. The vaporizer of claim 21, wherein the substance is a vaporizable
25. The vaporizer of claim 21, wherein the substance is a vaporizable
26. The vaporizer of claim 21, wherein the substance is a vaporizable
27. The vaporizer of claim 21, wherein the substance is a vaporizable
28. The vaporizer of claim 21, wherein the rings are of asbestos and the
29. The vaporizer of claim 21, wherein the rings are of a material of light color assuming a darker color upon being soaked in the substance and
30. The vaporizer of claim 1, further comprising a gripping ring on the
31. The vaporizer of claim 1, further comprising an indicator on the rotary member and marks on the outer wall of the container, the indicator cooperating with the marks to indicate the relative positions of the port
32. The vaporizer of claim 1, further comprising a gripping ring at the lower edge of the rotary member and cooperating detent means on the
33. The vaporizer of claim 1, further comprising indicating means on top of the rotary member for designating the substance to be vaporized.
Description:
The present invention relates to a device for vaporizing substances by means of electrical heating, particularly for disinfection of and medical treatment in rooms.
It is desirable for many purposes to add certain substances to the air in a highly dispersed form, by way of example substances such as scents or disinfectant substances. With highly volatile substances this may be effected by arranging porous bodies soaked in the substances involved in a given room so that the evaporation occurring at normal room temperature ensures the distribution of such substances in the atmosphere. Naturally, such an evaporation process highly dependent on room temperature and other factors is very indeterminate in respect of the quantity of substances so vaporized so that the method of spraying such substances into the atmosphere has largely been adopted, commonly using spray containers under internal gas pressure. However, this requires that the substances involved are present in the spray container is liquid or dissolved form in a highly gas-generating liquid, which is on the one hand inadmissible for many substances and, on the other, results in corresponding quantities of the gas-propelling liquid entering the atmosphere.
The present invention has for its object to eliminate the said disadvantages and relates to a device for vaporizing substances by means of electrical heating, particularly for disinfection of and medical treatment in rooms, characterized by a base designed for connection to an electrical power supply and provided with an electrical resistance heating element located in a fully enclosed housing comprising a broad lower portion and a narrower upper portion, by an annular container removably mounted on the base. The container is completely closed save for at least one opening in its exterior wall but possesses an interior encased chamber extending almost over the entire length of the container, into which the upper portion of the base fits, the container having its interior provided with annular carrier members for the substances to be vaporized while being equipped with a rotary member enclosing its upper end and the upper portion of its exterior wall with the opening in the manner of a bell, the rotary member having its jacket provided with at least one corresponding opening which can be brought to register more or less with the opening in the exterior wall of the container by rotation so as to increasingly open, starting from a zero position in which the opening in the exterior wall of the container is fully closed by the rotary member, the opening through which the vaporized substances can emerge to the outside from the interior space of the container.
A number of embodiments of the present invention will now be discussed in greater detail with reference to FIGS. 1 through 14 in the drawing in which
FIG. 1 is a diagrammatic perspective view of the two-piece device according to the invention;
FIG. 2 is an elevation, shown in section on the right, of the embodiment of the complete device according to this invention as shown in FIG. 1;
FIG. 3 is a diagrammatic perspective view of the connection of the device according to FIG. 2 to a power socket;
FIG. 4 is an electrical circuit diagram of a further embodiment of the base of the device according to FIG. 2;
FIG. 5 is a plan view of the cylindrical container of FIG. 6;
FIG. 6 is an elevation, shown in section on the right, of an interchangeable container of the device according to FIG. 2;
FIG. 7 is an elevation, shown in section on the right, of another embodiment of the complete device according to this invention;
FIG. 8 is a view corresponding to FIG. 7 of a further embodiment of the base of the device;
FIG. 9 is a plan view of the cylindrical container of FIG. 10;
FIG. 10 is an elevation, shown in section on the right, of an interchangeable container of the device according to FIG. 7;
FIGS. 11 through 13 are diagrammatic views of symbols for various substances contained in the container according to FIGS. 6 and 10;
FIG. 14 is an elevation, shown in section on the right, of another embodiment of the device.
A characteristic of the present devices for vaporizing substances by means of electric heating is the fact that they are formed of two principal portions diagrammatically indicated in FIG. 1. One portion is a base 10 and the other an annular container 11 which may be attached to the base. This design of the present device offers the advantage that the same base 10 may be used for various removably attachable containers 11 holding different substances to be vaporized.
FIG. 2 is an elevation of a two-piece device in assembled condition, the base 10 being located below and the container 11 above the dot-dash line in the outside view on the left of the vertical centre line. The base is designed for connection to the electrical power supply and is provided, in the embodiment of FIG. 2, with circular plugs 12 designed for insertion in a socket 13 of an electric current system which is diagrammatically shown in FIG. 3. If desired, the two plugs 12 may also be complemented by a third plug designed for grounding if the socket 13 is equipped with a third bush designed for grounding as indicated in FIG. 3. While being arranged in parallel with the centre axis in FIG. 2, the plugs 12 may, if formed of a sufficiently elastic material, be somewhat inclined towards the centre axis 14 in order to provide mechanical prestressing which ensures reliable attachment of the device to the socket 13. It is obvious that, for use of the present device in countries with differently standardized sockets for the current system, plugs of appropriately different design may be provided on the base 10, by way of example flat plugs 15 (FIG. 8). However, if the device is by way of example intended for use in vehicles, the base is provided with an appropriate plug-in connection for the current supply so that, by way of example in automobiles, the base 10 can be equipped with a plug-in connection for insertion in place of the cigar lighter.
The base 10 is provided with a fully enclosed housing that comprises a broad lower portion 16 and a narrower upper portion 17. Arranged in the broad lower portion 16 are the electrical resistance heating elements 18 which are connected to one of the two connecting pins 12. Further arranged in the lower portion 16 is a rheostat 181 connected, in series with the resistance heating elements 18, to other pin 12. The upper portion 17 is formed of a heat-resistant non-inflammable material, by way of example a suitable nylon material such as Makrolon. The resistance heating element 18 is so designed that an elevated temperature is generated in the upper portion 17 of the base when the device is operated by the electrical power supply, the temperature being dependent on the setting of the rheostat 181. The power input from the current supply is preferably in the range between 1 and 10 Watts. By way of example, two resistance heating elements 18 of 14,000 Ohms each and a rheostat 181 with a range of adjustment from 0 to 4,000 Ohms for a power supply system of 220 Volts have proved suitable. The selection of the resistance heating elements 18 and the rheostat 181 also depends on the temperature that is desired to be obtained in the upper portion 17, the substance to be vaporized in the container 11 and its volatilization temperature being the decisive factors. At all events the heating elements 18 and the rheostat 181 may, by selection of the electrical resistance values, readily be adjusted to all requirements for the volatilization of the substances contemplated.
The lower portion 16 advantageously consists of a transparent material and has its interior provided with a light source 23 connected to the plugs 12. In the embodiment according to FIG. 2 this electrical light source 23 consists of a glow-discharge lamp which is in the usual fashion connected, via a resistance 24, to the plugs 12. In the operation of the device according to FIG. 2 in connection with an electric current system this glow-discharge lamp 23 will light up after connection to the socket, which may be clearly observed through the wall of the lower portion 16 and the outer ring 21 which are both formed of a transparent material. On the one hand, the light serves as a signal and indicates that the device is in operation to vaporize substances. On the other hand, this light enables the base 10 to be used as a night light or auxiliary light source alone, i.e., without connected container 11. If desired, the rheostat 181 may also be combined, as shown in the circuit diagram according to FIG. 4, with an ON/OFF switch which consists, by way of example, of the OFF contact 182 and the ON contact 183 of the slide 184. In the position on the OFF contact 182 the circuit for the heating elements 18 and the light source 23 is then completely interrupted. Only in the position on the ON contact 183 of the slide 184 will the light source 23 begin to glow and the minimum power be supplied to the heating elements. However, it is also possible to connect the circuit for the light source 23 not to the ON contact 183 as shown in FIG. 4 but to the connecting line between the rheostat 181 and the two resistance heating elements 18 arranged in parallel; the brightness of the light source 23 will then be increased as the heating elements 18 are supplied with a higher voltage, i.e., more intensely heated. Instead of the design of the rheostat 181 with the ON/OFF contacts 183 and 182 shown in FIG. 4, any other design with an ON/OFF switch of the rheostat may be employed.
The rheostat 181 arranged in the lower portion 16 is provided with an upwardly extending rotary pin 185 which passes through the narrow upper portion 17 of the base 10, projects from the upper portion 17 and extends to the rotary member 36 of the container 11. The rotary pin 185 engages a socket 186 in the rotary member 36 so that the rotary member 36 and the rotary pin 185 along with the slide 184 in the rheostat 181 will always assume a very definite position relative to one another also if the container 11 and the rotary member 36 are removed from the base 10 as described in greater detail below, and replaced by another appropriate container 11 with a similar rotary member 36.
Provided in the base 10 of the device according to FIG. 2 for the improvement of heat conduction from the resistance heating elements 18 to the upper portion 17 is a duct formed of a material which is highly heat-conducting, such as a copper alloy commercially sold under the name of LATAN. The duct consists of an umbrella 187 covering the resistance heating elements 18 and continues in the shape of a tube 188 which extends into the narrow upper portion 17 on the interior surface of which it rests.
In order to shield the light source 23 against the heat of the adjacent resistance heating elements 18, the embodiment of the device according to FIG. 2 is provided with a wall 190 which is advantageously reflecting. Again, a reflecting shield 189 is provided between the rheostat 181 and the resistance heating elements 18, the shield being so designed that the heat enamating from the rheostat 181 may pass into the duct 188.
The base 10 to be connected to the power supply system must be designed, in respect of material and construction, so as to comply with the official regulations in force. The underside 25 of the base 10 may be used to bear appropriate data relating to the safety factor and other instructions.
As appears from the longitudinal section on the right in FIG. 2, the upper portion 17 forms a unitary body with the broad lower portion 16, this body being locked in a suitable groove in the outer ring 21 by means of a bolt 20. Located between the lower portion 16 and the outer ring 21 is a gap which is open in the upward direction and serves for insertion of the lower edge 22 of the container 11.
As mentioned above in connection with FIG. 1, the two-piece device for vaporizing substances consists, apart from the base 10 described in great detail above, of a container 11 shown alone in FIg. 6 and together with the base 10 in FIg. 2. This container 11 is of annular configuration and fully closed save for a slot 35 in the exterior wall 30. Inner wall 32 of container 11 defines interior recess 31 which extends over almost the entire length of the container and interior chamber of the container is annular in cross-section. The recess 31 is so designed that the upper portion 17 of the base fits into it. In order to obtain the best possible heat transfer from the upper portion 17 of the base 10 to the inner wall 32 of the container 11, the inner surface of the wall 32 of the container should contact the outside surface of the upper portion 17 of the base without forming an air gap (the air gap indicated in FIG. 2 is shown only for better identification of the upper portion 17 and the inner wall 32 but should not be present in reality). The exterior wall 30 of the container 11 projects somewhat from its bottom 34 and forms a skirt 22 which serves, as previously stated with reference to FIG. 2, for insertion of the container in the gap between the lower portion 16 and the outer ring 21 of the base 10. Since the lower portion of the container 11 may be somewhat compressed owing to the extended inner recess 31, proper dimensioning of the outer ring 21 at the base 10 may ensure that the container 11 is securely gripped by this outer ring 21 after insertion. If desired, the skirt 22 of the container and the outer ring 21 may be provided, at a suitable location, with a projection and a groove so that the container 11 can be inserted in the base 10 only in a certain position relative to the base.
Provided at a certain point in the outer wall 30 of the container 11 is a slot 35 with a width of between 2 and 8 mm, and a length not less than 20 mm, indicated by broken lines in FIG. 6. This slot serves for communication of the interior chamber 33 of the container 11 with the outside, but is normally closed by the rotary member 36 which covers the upper side 37 of the container 11 and the upper part of its outside wall 30 as a bell would do. The rotary member 36 is also equipped with an opening 41 so that, if the rotary member 36 is rotated, its opening 41 can be caused more or less to register with the slot 35 in the outside wall 30 of the container in order that, starting from a zero position in which the slot 35 in the outside wall 30 of the container is fully closed, first a fraction, then an increasing portion and finally the entire slot in the outside wall 30 of the container will be opened for the emergence of the substances to be vaporized from the interior space 33 of the container 11.
Provided on the upper edge of the rotary member 36 are a gripping ring 38 and detent recesses which co-operate with corresponding detents on the outer wall 30 of the container 11 so as to define both the zero position and the maximum position in which the opening 41 of the rotary member 36 completely closes and, respectively, completely opens the slot 35 in the exterior wall 30 of the container 11. The rotary member 36 may advantageously be provided with an indicator 39 which moves, together with the rotary member 36 when he latter is rotated, past suitable marks on the outside wall 30 of the container 11 and shows both the zero position and the maximum position of the rotary member 36. If desired, marks other than the zero position may be provided with numerals such as for the quantity of vaporized substance supplied to the atmosphere per hour in any one position.
As shown in FIGS. 5 and 9, the upper side of the rotary member 36 is provided with an indicator 40 in the form of a circular mark index which shows what kind of substance to be vaporized the container 11 holds. This indicator may, by way of example, consist of a symbol, such as an insect as shown in FIG. 5, which is designed to indicate that the container holds an insecticide to be vaporized. The borders of the symbol may be in a color that corresponds to the color of the gripping ring 38. Another suitable symbol is shown in FIG. 11 which, by way of example, identifies a container with a flower scent. The symbol according to FIG. 12 is designed to characterize a forest scent while the symbol in FIG. 13 would indicate herb, peppermint and similar scents.
Located in the interior chamber 33 of the container 11 are annular carrier members 42 for the substances to be vaporized which consist, by way of example, of a porous plastic material or a cellulosic material and are soaked in the substance involved. While generally all porous carrier materials which do not themselves vaporize are suitable for scents, vaporizable medical substances and insecticidal or disinfectant substances frequently impose special demands on the carrier material. By way of example, mineral porous materials such as asbestos have proven suitable for this purpose. Carrier rings 42 formed of asbestos have also proved their suitability for soaking in dimethyl 2.2 dichlorovinyl phosphate which represents an insecticidal substance to be vaporized. It is also of advantage for the outside wall 30 of the container 11 to be formed of a transparent material at least in its lower portion which projects from the rotary member 36 since carrier rings 42 may then be used of which the colour gives an indication of the quantity of the substance to be vaporized which is still available. If carrier rings formed of light asbestos are employed, they will commonly assume a darker coloration after being soaked in the substance to be vaporized, and resume their originally lighter colour only when the substance involved has been largely consumed.
The base 10 of the embodiment according to FIG. 7 is provided with a fully enclosed housing that comprises a broad lower portion 16 and a narrower upper portion 17. The narrow upper portion 17 encloses the electrical resistance heating element 18 which is connected, via the lead 19, to the right-hand one of the two connecting pins 12. This upper portion 17 consists of a heat-resistant non-inflammable material, by way of example a suitable nylon material such as Makrolon. The resistance heating element 18 is so designed that a temperature higher than about 120°C is generated in the upper portion 17 of the base when the device is operated by the electrical power supply. The power input from the current supply system is preferably in the range between 1 and 5 Watts. By way of example, a heating element 18 with a resistance of 33,000 Ohms has proved appropriate for a power supply system of 220 Volts. In connection with a power supply system with a voltage of 110 Volts a heating element with about 15,000 Ohms may be employed while a heating element with a resistance of 56,000 Ohms is appropriate for power supply systems with a voltage of 440 Volts. The selection of the resistance heating element 18 also depends on the temperature that is desired to be obtained in the upper portion 17, the substance to be vaporized in the container 11 and its volatization temperature being the decisive factors. At all events the heating element 18 may, be selection of its electrical resistance, readily be adjusted to all requirements for the volatilization of the substances contemplated.
As appears from the longitudinal section on the right in FIG. 7, the upper portion 17 here forms a unitary body with the broad lower portion 16, this body being locked in a suitable groove in the outer ring 21 by means of a bolt 20. Located between the lower portion 16 and the outer ring 21 is a gap which is open in the upward direction and serves for insertion of the lower edge 22 of the container 11. The lower portion 16 advantageously consists of a transparent material and has its interior provided with a light source 23 connected to the plugs 12. In the embodiment according to FIG. 7 this electrical light source 23 consists of a glow-discharge lamp which is in the usual fashion connected, via a resistance 24, to the plugs 12. In the operation of the device according to FIG. 7 in connection with a current system this glow-discharge lamp 23 will light up after connection to the socket, which may be clearly observed through the wall of the lower portion 16 and the outer ring 21 which are both formed of a transparent material. On the one hand, the light serves as a signal and indicates that the device is in operation to vaporize substances. On the other hand, this light enables the base 10 to be used as a night light or auxiliary light source alone, i.e., without connected container 11.
Provided in the outer wall 30 of the container 11 at a predetermined regular distance from one another are four holes 35 with a diameter of between 3 and 6 mm, indicated by broken lines in FIG. 10. These holes serve for connection of the interior chamber 33 of the container 11 with the outside, but are normally closed by the rotary member 36 which covers the upper side 37 of the container 11 and the upper part of its outside wall 30 as a bell would do. The rotary member 36 is also equipped with four passage holes (not visible in FIG. 10) so that, if the rotary member 36 is rotated, its holes can be consecutively brought into register with the holes 35 in the outside wall 30 of the container in order that, starting from a zero position in which all holes of the outside wall 30 of the container are closed, first one hole, then two holes, then three holes and finally four holes in the outside wall 30 of the container can be opened for the emergence of the substances to be vaporized from the interior chamber 33 of the container 11.
Provided on the lower edge of the rotary member 36 are a gripping ring 38 and detent recesses which co-operate with corresponding detents on the outer wall 30 of the container 11 so as to define both the zero portion of the rotary member 36 and those positions in which one or several holes of the rotary member 36 are in register with the holes 35 in the exterior wall 30 of the container 11. The gripping ring 38 may advantageously be provided with an indicator which moves, together with the rotary member 36 when the latter is rotated, past the marks 39 on the outside wall 30 of the container 11 and shows both the zero position of the rotary member 36 and the number of the holes 35 in the container 11 which have been opened. If desired, the zero position and the marks 39 may be designated by numerals 0, 1, 2, 3, 4 or in some other suitable manner.
The two-piece devices for the vaporization of substances as disclosed above may be used not only for vaporizing scents or insecticides but suitable carrier materials may also be soaked in medicinal substances which, when vaporized, enable prophylactic treatment of the respiratory system or treatment for disorders in the respiratory system to be effected. Vaporizable germicidal and disinfecting substances may also be employed with the present invention. Since container 11 can be removed from the base 10 when and as desired, it is also possible to remove a container not yet exhausted, to close it by rotating the rotary member 36 into its zero position, to store it and to use the base 10 with some other container 11 of different content.
In the shown embodiments of the device for vaporizing substances it is a particular advantage that the intensity of vaporization can be adjusted by the rheostat 181 actuated by the rotary member 36, the opening 41 for the emergence of the vaporized substances from the slot 35 in the container being increased at the same time. This measure has proved to be of advantage particularly in the disinfection of rooms and in preparing the air in closed rooms for medical treatments, such as in the presence of disorders in the respiratory system.
The base 10 of the embodiment according to FIG. 14 is provided with a fully enclosed housing that comprises a broad lower portion 16 and a narrower upper portion 17. The narrow upper portion 17 encloses an electrical incandescent lamp 18 which is connected, via the leads 19, to the two connecting pins 12. This upper portion 17 consists of a heat-resistant, non-inflammable material, by way of example a suitable nylon material such as Makrolon. The incandescent lamp 18 is so designed that a temperature about 5°-10°C higher than the room temperature is generated in the upper portion 17 of the base when the device is operated by the electrical power supply. The power input from the current supply system is preferably in the range between 1 and 5 Watts. If desired, the incandescent lamp 18 can be connected to the connecting pins 12 via a series resistance. The selection of the lamp 18 also depends on the temperature that is desired to be obtained in the upper portion 17, the substance to be vaporized in the container and its volatilization temperature being the decisive factors. At all events the lamp 18 may, by adequate selection of its electrical resistance, readily be adjusted to all requirements for the volatilzation of the substances contemplated.
As appears from the longitudinal section on the right in FIG. 14, the upper portion 17 forms a unitary body with the broad lower portion 16, this body being locked in a suitable groove in the outer ring 21 by means of a bolt 20. Located between the lower portion 16 and the outer ring 21 is a gap which is open in the upward direction and serves for insertion of the container 11. The upper portion 17 advantageously consists of a transparent material. In the operation of the device in connection with a current system this incandescent lamp 23 will light up after connection to the socket, which light may be clearly observed through the wall of the lower portion 16 and the outer ring 21 when both are formed of a transparent material. On the one hand, the light serves as a signal and indicates that the device is in operation to vaporize substances. On the other hand, this light enables the base 10 to be used as a night light or auxiliary light source alone, i.e., without connected container 11.
In the latter embodiment the lamp 18 is attached to the inner wall of the upper portion by means of a bridge piece. It is also possible to provide the lower ring portion 21 of the base 10 with a lamp holder (socket), into which the incandescent lamp is screwed or inserted, after which the upper portion 17 is placed over the lamp 18 and is attached to outer ring 21 by means of the edge 20. It is advantageous to use on oblong lamp 18 which fills substantially the full inner room of the thin neck of the upper portion. It is also possible to use an oblong lamp 18 which is mounted in a lamp holder in the lower portion, to completely omit the thin neck of the upper portion 17 in case the lamp bulb projects sufficiently far out of the broad part of the upper portion 17. The last mentioned embodiment is particularly advantageous for devices which operate on a power supply system of low voltage or on a battery.