WO2010136916A1

WO2010136916A1 - A radiant heating device

Info

Publication number: WO2010136916A1
Application number: PCT/IB2010/051877
Authority: WO
Inventors: Stefano Nasi; Alessio Bonomini
Original assignee: Mo-El S.R.L.
Priority date: 2009-05-28
Filing date: 2010-04-29
Publication date: 2010-12-02
Also published as: CN101902844A; TW201103355A; ITMI20090948A1

Abstract

It is disclosed a radiant heating device comprising: a bearing structure (2), carrying at least one holding chamber (6); at least one lamp (8) having at least two terminals (11) for electric connection housed in the holding chamber (6), and a radiant portion (8a) extending externally of the holding chamber (6) along a geometric extension axis (X). At least one elastic support element (15) is in engagement with the bearing structure (2) and sealingly fitted around said lamp (8) for elastically coupling said lamp (8) to the bearing structure (2) and closing said holding chamber (6). The electric-connection terminals (11) are mutually spaced apart by an amount (D) smaller than the linear extension of the radiant portion (8a) of the lamp (8), to be detected along said geometric extension axis (X).

Description

A RADIANT HEATING DEVICE

D e s c r i p t i o n

The present inventions relates to a radiant heating device comprising the features set out in the preamble of claim 1.

In particular, in the present description, reference will be specifically made to radiant devices used for heating both indoor and outdoor surfaces and/or environments, without however intending to limit application of the present invention to lighting devices or radiant devices of other kind, adapted to emit energy on wavelengths that can be in the visible spectrum (by means of quartz-iodine lamps, for example) and in the infrared spectrum.

Heating devices by radiation are known which use an electrically powered lamp as the heat source.

Irrespective of the type of lamp used, in the devices of the known art it is provided that the lamp should be inserted in a holding frame comprising electric connections powering the lamp and securing it to the frame .

Due to the high operating temperature of the particular lamps used in the devices of this type, in order to prevent the electric connections from being damaged or at all events the efficiency of same being impaired, said connections are made of materials capable of resisting the high temperatures and having a low heat- transmission coefficient. _ p „

In devices of the known art, in order to inhibit infiltration of dust or water in outdoor applications, in the regions where the electric contacts are present (so that short-circuits might occur), a shield made of glass, or in any case of a material as much as possible transparent to the operating wavelengths, carries out sealing of the frame in which the lamp is contained.

In fact, the radiation emitted by the lamp must necessarily pass through the glass sealing the frame, being partly reflected, partly absorbed and therefore only partly transmitted. This unavoidably involves lowering of the transmission yield of the radiation of the heating device.

In addition, the materials necessarily used for manufacturing the electric connections of the lamp

(ceramics, mica, alumina) are brittle or at all events very stiff. Taking into account the fact that the electric connections also act as a support for the lamp, the integrity of the lamp can be seriously impaired even in case of little shocks or vibrations transmitted to the holding frame.

In addition, the radiation reflected by the glass to the inside of the frame causes a temperature increase within the frame and therefore the different thermal- expansion coefficients between lamp and electric connections give rise to mechanical stresses in the lamp that can cause breaking of same.

To obviate the above drawbacks, the Applicant has already proposed a radiant device without the presence of glass, disclosed in document WO 2005/036928, provided with a linear lamp supported at the opposite ends by two elastic support elements of heat-resistant elastomer material, elastically fitted on the lamp so as to conveniently protect it against shocks and vibrations and hermetically in engagement with the bearing structure. The electric terminals of the lamp are each housed within a sealingly closed holding chamber so that the electric parts are appropriately protected against possible penetration of dust, humidity and/or water splashes.

The Applicant has however found that also the radiant devices without glass of the known art can be further improved under different points of view, above all in terms of construction simplicity, compactness in size, reliability of use and production costs. In fact, due to the requirement of housing the electric terminals of the lamp in respective holding chambers hermetically interconnected with each other to avoid penetration of dust, humidity, water and other external agents, a significant structural complication of the device as a whole is encountered.

The different assembled components increase the number of points of potential penetration of the external agents towards electric parts, making the device less reliable or involving the necessity to pay particular attention and carrying out severe controls during the production and servicing steps .

The Applicant has also found that known devices have limits of reliability when they are installed in a vertical orientation. In fact, the heat produced by the lamp gives rise to a flow of hot air going up along the lamp and thus overheating the elastic support element and the other components associated with the upper end of the lamp.

The Applicant has also found it difficult to maintain the bulkiness and production costs of the radiant devices within acceptable limits, especially when particular requirements involving use of several lamps distributed around a central point are to be met.

The technical task underlying the present invention is to conceive a radiant heating device capable of obviating the above mentioned drawbacks .

In particular, it is an object of the present invention to provide a radiant heating device comprising: - a bearing structure, carrying at least one holding chamber;

- at least one lamp having at least two terminals for electric connection housed in said at least one holding chamber, and a radiant portion extending externally of the holding chamber in a geometric extension axis; at least one elastic support element in engagement with the bearing structure and sealingly fitted around said lamp for elastically coupling said lamp to the bearing structure and closing said holding chamber; characterised in that the electric-connection terminals are mutually spaced apart by an amount "D" smaller than the linear extension of the radiant portion of the lamp, to be detected along said geometric extension axis ,

The electric-connection terminals are therefore disposed at a mutually closer position, without damaging the linear extension of the lamp with which the radiation power is strictly correlated. Thus the overall structure of the device can be greatly simplified. In particular, it is possible to limit the number of components required for achieving insulation of the electric parts from the external environment, thus obtaining advantages in terms both of production costs and reliability.

Also obtained is a significant reduction in the bulkiness of the device without the efficiency in terms of heating being reduced.

If necessary, the device 1 can be disposed in a vertical orientation with the holding chamber disposed at the bottom without running the risk of overheating the components operatively disposed in the vicinity of the lamp terminals.

Furthermore, production of radiant heating devices provided with several lamps differently distributed around a central bearing structure becomes easy, in order to meet particular requirements in terms of radiation intensity and distribution.

Description of a preferred but not exclusive embodiment of a radiant heating device is now given hereinafter by way of non-limiting example and illustrated in the accompanying drawings, in which:

- Fig. 1 is a perspective view of a radiant heating device in accordance with the present invention;

- Fig. 2 shows the device of Fig. 1 sectioned along the geometric axis of one of the end portions of the lamp;

- Fig. 3 shows a detail seen in Fig. 2 to an enlarged scale;

- Fig. 4 is a section taken along line IV-IV in Fig. 3;

- Fig. 5 shows a construction design of the device referred to in the previous figures; - Fig. 6 shows a construction design of a first alternative embodiment of the device in question;

- Fig. 7 shows a construction design of a second alternative embodiment of the device in question.

With reference to the drawings, a radiant heating device in accordance with the present invention has been generally identified with reference numeral 1.

Device 1 comprises a bearing structure 2 having a box- shaped body 3 preferably consisting of a base portion 4 to which a closing cap is coupled, after interposition of a seal 5a, so as to define at least one holding chamber 6.

A bracket 7 can be engaged to the holding chamber 6 for fastening the radiant device 1 to a post (not shown) , a wall or other bearing structure, such as a base 7a resting on the ground, for example. If necessary, device 1 can be disposed in a vertical orientation with the holding chamber 6 disposed at the bottom, as shown in Fig. 5 by way of example.

Operatively in engagement with the bearing structure 2 is at least one lamp 8 preferably comprising a tubular housing 9 extending along a geometric extension axis X.

The tubular housing 9 is preferably made of fused quartz or other material transparent to the radiation emitted by the lamp 8, resisting to high temperatures and preferably also to strong and sudden changes of temperature caused by water jets or splashes, for example.

The tubular housing 9 lodges at least one incandescent filament 10, preferably a carbon or tungsten filament, extending parallel to the geometric extension axis X and electrically connected between the first and second electric-connection terminals 11.

Preferably, the incandescent filament 10 extends at a radiant portion of lamp 8, over a length shorter than the linear extension of the tubular housing 9. The electric-connection terminals 11 are connected to the incandescent filament 10 by respective connecting filaments 12 housed within at least one, preferably two, respective end portions 8b of lamp 8, disposed in the extension of the radiant portion 8a. The connecting filaments 12, each extending over a length at least as long as 25 mm, a length of 75 mm for example, and preferably not exceeding 100 mm to maintain a satisfactory size compactness, are each formed with a conductor having an electric resistance considerably lower than that of the incandescent filament 10. In this manner the end portions 8b of lamp 8 during operation can maintain a considerably lower temperature than the operating temperature reached by the radiant portion 8a of lamp 8, due to heating produced by the incandescent filament 10.

The electric-connection terminals 11 of lamp 8 are housed in the holding chamber 6 inside which a terminal board or other suitable devices (not shown) for wiring of lamp 8 with a power cord 13 are disposed, which power cord is engaged, through the closing cap 5 of the holding chamber 6, by a tightly sealed fairlead 13a. A switch 14 can be provided which is sealingly engaged through the closing cap 5 and electrically connected between the power cord 13 and the lamp 8 inside the holding chamber 8, to enable switching on and off of lamp 8. The switch 14 is preferably of the waterproof type and/or conveniently protected by sealing means to prevent penetration of dust and water.

The mechanical connection between lamp 8 and bearing structure 2 is obtained by at least one elastic, preferably monolithic, support element 15, made of a heat-resisting elastomeric material, silicone rubber for example. The elastic support element 15 is in engagement with the bearing structure 2 and sealingly fitted around lamp 8, to elastically couple the latter to the bearing structure 2 and close the holding chamber 6 preferably in a hermetic manner.

In greater detail, in the example shown, each end portion 8b of lamp 8 is sealingly fitted through a respective elastic support element 15, in turn sealingly in engagement close to a through opening 16 provided in the base portion 4 of the box-shaped body 3.

To this aim, each elastic support element 15 can advantageously comprise an inner tubular portion 17 and an outer tubular portion 18 disposed mutually concentric and joined to each other in the vicinity of an end edge 15a external to the holding chamber 6 where the elastic support element 15 has a tapering portion having a frustoconical configuration diverging towards the holding chamber 6. Αn annular seat is defined between the inner tubular portion 17 and outer tubular portion 18, said seat being susceptible of engagement by tight fit in the axial direction with a supporting collar 19 projecting externally of the holding chamber 6, around each of the through openings 16 that open into the holding chamber itself. — Q —

Each elastic support element 15, previously adapted by its inner tubular portion 17 around the respective end portion 8b of lamp 8, is suitable to be fitted on the supporting collar 19, so that the outer tubular portion 18 causes the hermetic seal of the respective through opening 16.

Advantageously, two or more axial ribs 20 can be circumferentially distributed on the outer surface of the inner tubular portion 17. In greater detail, in the example shown the inner tubular portion 17 of each elastic support element 15 is provided with two axial ribs 20, located at diametrically opposite positions in a plane orthogonal to a lying plane of the lamp 8 containing said geometric extension axis X.

Due to the presence of the axial ribs 20, the interference between the inner tubular portion 17 and the supporting collar 19 takes place on relatively reduced surfaces, so that the end portion 8b of lamp 8, fitted on the respective elastic support element 15, can be easily fitted through the through opening 16 defined in the supporting collar 19. When assembly has been completed, the axial ribs 20 compressed between the supporting collar 19 and the inner tubular portion 17 fitted on lamp 8, at all events ensure a steady anchoring of said lamp 8 relative to the bearing structure 2, without further engagement elements being required for the purpose.

A possible alternative embodiment (not shown) can contemplate, instead of the axial ribs 20, the presence of a stiff annular insert to be engaged by tight fit between the supporting collar 19 and the inner tubular portion 17, after the elastic support element 15 provided on the end portion 8b of lamp 8 has been fitted on the supporting collar itself.

When assembly is over, the radiant portion 8a of lamp 8 extends externally of the holding chamber 6, between the elastic support elements passed through by the end portions 8b taking the respective electric-connection terminals 11 inside the holding chamber 6.

Advantageously, the electric-connection terminals 11 are mutually spaced apart by a smaller amount than the linear extension of the radiant portion 8a of lamp 8, detectable along said geometric extension axis X. Lamp 8, or at least the radiant portion 8a of said lamp, therefore has a curvilinear or curved linear extension, following a U-shaped configuration for example, as shown in Figs. 1 to 4, or in the form of an arc of a circle as diagrammatically shown in Figs. 5 and 6.

It is therefore possible to give the lamp 8 a desired linear extension, adapted to the different requirements in relation to the power and distribution of the radiation produced thereby, while maintaining the electric-connection terminals 11 at a mutually closer position. In particular, the electric-connection terminals 11 can be disposed within the same holding chamber 6 or in respective chambers defined in the same box-shaped body 3.

Therefore an important structural simplification of the radiant device 1 is achieved, as well as a great reduction in the overall bulkiness of same. In particular, as compared with the known art, a reduction is obtained in the number of components required for enabling sealed insulation of the electric-connection terminals 11 and the parts designed for connection of said terminals to the power cord 13. In particular, it is possible to place all electric connections within the same holding chamber 6, which is advantageous as regards reliability in terms of tightness and construction simplicity.

Location of the electric-connection terminals 11 in the same box-shaped body 3 further enables a radiant heating device 1 having a vertical extension to be manufactured, said device being also adapted for resting on the floor, as shown in Fig. 5 by way of example, without involving risks of the elastic support elements 15 and/or the electric parts being overheated. In fact, the elastic support elements 15, placed on the box-shaped support 3 from which lamp 8 rises, are not grazed by the hot air flow going up along the lamp 8 itself and the shielding bulkhead 24.

Housed in the holding chamber or chambers of the same box-shaped body 3 can be the electric terminals of several lamps distributed around the box-shaped body itself, as shown by way of example in Figs. 5 and 6.

As better viewed from Figs. 1 and 2, the device 1 can further comprise at least one parabolic reflector 21 shaped like a half-shell, housing the radiant portion 8a of lamp 8 in a concavity thereof. The parabolic reflector 21, made of stamped plate for example, preferably has an attachment end 21a engaged by tight fit in a coupling groove 22 defined in the bearing structure 2. Preferably, a seal 23 of thermal- insulation material, housed within the coupling groove 22, retains the parabolic reflector 21 by friction, ensuring steadiness of same. Advantageously associated with the parabolic reflector 21 can be a shielding bulkhead 24 passed through by the radiant portion 8a of lamp 8, in the vicinity of the elastic support elements 15. The shielding bulkhead 24 oriented in an oblique direction to the geometric extension axis X of lamp 8, conveniently protects the elastic support elements 15 from the radiation emitted by lamp 8 during operation, thus avoiding overheating of same.

Further associated with the bearing structure 2 can be a protective casing 25 extending in the continuation of the box-shaped body 3 for housing the lamp and the parabolic reflector 21. The protective casing 25 has a protection grid 26 disposed in front of the lamp 8, on the opposite side from the parabolic reflector 21. Preferably, ventilation slits 28 are formed on a rear wall 27 of the protective casing, disposed behind the parabolic reflector 21 on the opposite side relative to the protection grid 28.

Claims

C L A I M S

1. A radiant heating device comprising: a bearing structure (2), carrying at least one holding chamber (6);

- at least one lamp (8) having at least two terminals (11) for electric connection housed in said at least one holding chamber (6) , and a radiant portion (8a) extending externally of the holding chamber (6) along a geometric extension axis (X) ; at least one elastic support element (15) in engagement with the bearing structure (2) and sealingly fitted on said lamp (8) for elastically coupling said lamp (8) to the bearing structure (2) and closing said holding chamber (6); characterised in that the electric-connection terminals (11) are mutually spaced apart by an amount (D) smaller than the linear extension of the radiant portion (8a) of the lamp (8), to be detected along said geometric extension axis (X) .

2. A device as claimed in claim 1, wherein the radiant portion (8a) of the lamp (8) extends between two end portions (8b) sealingly fitted through said at least one elastic support element (15) and each carrying one of said electric-connection terminals (11) .

3. A device as claimed in claim 2, wherein each of the end portions (8b) of the lamp (8) is. fitted through a respective elastic support element (15) .

4. A device as claimed in one or more of the preceding claims, wherein the bearing structure (2) comprises a box-shaped body (3) defining said holding chamber (6) and carrying said at least one elastic support element ( 15 ) .

5. A device as claimed in the preceding claim, wherein said at least one elastic support element (15) comprises an inner tubular portion (17) fitted around the lamp (8) and in engagement with the box-shaped body (3) at a through opening (16) .

6. A device as claimed in the preceding claim, wherein said box-shaped body (3) has at least one supporting collar (19) extending around said through opening (16) and in engagement by tight fit between said inner tubular portion (17) and an outer tubular portion (18) of the elastic support element (15) .

7. A device as claimed in claim 5 or 6, wherein said inner tubular portion (17) externally has at least two circumferentially-distributed axial ribs (20) .

8. A device as claimed in one or more of the preceding claims, further comprising at least one parabolic reflector (21) shaped like a half-shell, housing the radiant portion (8a) of the lamp (8) and having an attachment end (21a) engaged by tight fit in a coupling groove (22) defined in the bearing structure (2) .

9. A device as claimed in one or more of the preceding claims, further comprising at least one shielding bulkhead (24) passed through by the radiant portion (8a) of the lamp (8) in the vicinity of said at least one elastic support element (15) and oriented obliquely to said geometric extension axis (X) .

10. A device as claimed in one or more of the preceding claims, comprising a plurality of lamps (8) distributed around said bearing structure (2) and having respective electric-connection terminals (11) housed in said at least one holding chamber (6) .