[0001] The present invention relates to a patio heater comprising a base portion adapted
to accommodate a heat source, a heat generator above the base portion, and a metal
reflector dome above the heat generator for reflecting the heat downwards.
[0002] Propane-fuelled heaters are widely used for heating outdoor spaces. These so-called
patio heaters are used to provide heat in outdoor areas in restaurants, taverns or
domestic outdoors facilities or similar hospitality environments for instance in chilly
evenings. Residential use of patio heaters have grown over the years and are also
used for semi-outdoor hospitality occasions e.g. for providing heat in an open tent
or a pavilion, whereby the comfort of the heat provided by the patio heater is combined
with a shelter in case of rain.
[0003] However, the metal reflector dome of the patio heater becomes hot due to the contact
with the hot gasses generated by the combustion of the gas. The hot gasses tend to
rise and thereby heat the dome. If the heater is positioned close to a tent, the tent
fabric in the near vicinity of the patio heater might be damaged or even be set alight.
Such tents are typically made of a polymeric material which will melt or wrinkle if
subjected to a heat above a certain temperature which can easily be reached by the
gas-fuelled burner of the heater. Moreover there is typically no use for the generated
heat rising above the dome of the patio heater.
[0004] One way of attempting to reflect the heat downwards and prevent surplus heat above
the dome of the patio heater is known from
WO 2009/146421 where a double dome is provided with an air gap between the two domes. However, this
solution does not fully prevent heat build-up above the double dome and that the metal
dome gradually becomes hot during use whereby the risk of damaging tent fabric or
other materials close to the top of the heater is increased.
[0005] It is therefore an object of the present invention to provide a safe guard towards
excessive heat generation above the upper surface of the reflector dome of the patio
heater.
[0006] This object is achieved by a patio heater comprising a base portion adapted to accommodate
a heat source, a heat generator above the base portion, and a metal reflector dome
above the heat generator for reflecting the heat downwards, wherein a layer of mineral
wool insulation is arranged above the reflector dome.
[0007] Hereby, a thermal insulation is provided which effectively shields the surroundings
from the heat from the upper surface of the reflector dome. It is found that the temperature
above the layer of mineral wool insulation can be kept at a "hand warm" temperature
level. This effectively prevents wrinkling or melting of a polymeric tent fabric arranged
above the patio heater, and it also avoids discomfort in case someone accidentally
get too close the reflector dome. By the invention it is moreover realised that the
use of a layer of mineral wool insulation does not incur any fire risk as the mineral
wool fibre insulation slabs are fire-resistant.
[0008] In a first embodiment of the invention the layer of mineral wool insulation is generally
shaped as the reflector dome and is supported by an upper surface of the reflector
dome. Moreover, an upper support layer may be arranged on top of the layer of mineral
wool insulation. This support layer may preferably be made of a metal sheet material,
in particular steel or aluminium. By providing the mineral wool fibre slabs on a support
layer, a low density insulation product may be used.
[0009] The reflector dome may be made in a sandwich construction with a lower and upper
support layer with a slab of the mineral wool insulation therebetween. This may be
advantageous as the mineral wool insulation board then is protected by the support
layers and thereby is prevented from deteriorating. The at least one support layer
and the mineral wool insulation layer may be bonded together by glue, which preferably
is heat resistant and inflammable. As an alternative, the at least one metal layer
and the mineral wool insulation layer are mechanically fixed to each other, such as
by a threated mounting assembly.
[0010] In an embodiment of the invention, the upper support layer of the dome is made of
a wire mesh. Hereby, a reflector with a low amount of metal may be provided which
results in less material which is heat conductive.
[0011] An outer rim of the reflector dome and an outer rim of the upper support layer may
preferably be interconnected. Alternatively or in addition, the reflector dome and
the layer of mineral wool insulation may be mechanically fixed to each other, such
as by a threated mounting assembly. Hereby, there is achieved an insulated reflector
dome which is held together as one unit.
[0012] In another embodiment, the layer of mineral wool insulation is supported by a lower
support layer arranged above the reflector dome. The lower support layer may be made
of a metal wire mesh. Moreover, an upper support layer may be arranged on top of the
layer of mineral wool insulation, wherein the upper support layer may be made of a
metal wire mesh. Hereby, suitable reflector domes having a thermal insulation provided
thereon may be achieved.
[0013] By the invention it is found sufficient in order to achieve the necessary heat insulation
that the layer of mineral wool insulation has a thickness of between 10 and 100 mm,
preferably between 15 and 60 mm, more preferably between 20 and 50 mm.
[0014] A second aspect of the invention concerns a use of a mineral wool insulation board
as a heat shield for a patio heater, wherein the mineral wool insulation board is
arranged above an upper surface of a reflector dome of the patio heater. According
to this aspect of the invention, existing patio heaters may be improved by having
a mineral wool insulation board arranged above the reflector dome.
[0015] In the following, the invention is described in more detail with reference to the
drawings, in which:
figure 1 is a schematic side view of a conventional patio heater;
figure 2 is a detailed cross-sectional side view of a first embodiment of the invention;
figure 3 is a detailed cross-sectional side view of a second embodiment of the invention;
figure 4 is a schematic side view of a third embodiment of the invention;
figure 5 is a top view of the embodiment shown in fig. 4 or 5,
figure 6 is a perspective view of the embodiment shown in fig. 4 or 5 and
figure 7 is a schematic side view of a fourth embodiment of the invention.
[0016] With reference to figure 1, a conventional patio heater is shown. The patio heater
comprises a base portion with a housing 1 wherein a heat source, such as a propane
gas vessel, may be accommodated. A pole 2 extends above the base portion and on the
distal top end of the pole 2 a heat generator 3 is provided. The heat generator may
be a gas burner which is fuelled from the heat source in the housing 1 via a supply
hose (not shown) inside the pole 2. Above the heat generator 3 the patio heater is
provided with a cap in the form of a metal reflector dome 4 which reflects the heat
radiation from the heater downwards. The reflector dome 4 is attached to the heat
generator 3 and the pole 2 by suitable fastening means 8. The reflector dome 4 has
an upper surface 11 and since the reflector dome conventionally is made of a metal
sheet the upper surface 11 becomes hot during use. The heat emitted from the upper
surface 11 of the reflector dome 4 is normally wasted.
[0017] According to a first embodiment of the invention and as shown in fig. 2, the reflector
dome 4 is provided with a layer of mineral wool insulation 5 which in this embodiment
is sandwiched between an outer, upper support plate 6 and the upper surface 11 of
the reflector dome 4. The layer of mineral wool insulation 5 is preferably provided
as a mineral wool insulation board comprising mineral fibres bonded together in conventional
manner. The upper support plate 6 and the layer of mineral wool insulation 5 are mechanically
fixed to the reflector dome 4 by a threated mounting assembly 8. Alternatively, the
upper support plate 6 may be fixed to the mineral wool insulation layer 5 by an adhesive
bonding, e.g. by a heat-resistant glue. Thereby the heat bridge from the reflector
dome 4 to the upper support plate 6 can be eliminated.
[0018] The outer rim of the reflector dome 4 and of the upper support plate 6 may be interconnected
6 (not shown), so that the layer of mineral wool insulation 5 is completely enveloped.
This reduces or even eliminates any tendency of the mineral wool insulation to disintegrate
as a result of wear and tear. The upper plate 6 is provided with a shape corresponding
to the shape of the reflector 4. The mineral wool insulation 5 may also be preshaped
in the desired form but may also be provided in a conventionally flat shape with a
relative low density whereby the mineral insulation 5 may be easily shaped by the
upper support plate 6.
[0019] In another embodiment, as shown in fig. 3, the layer of mineral wool insulation 5
is provided as a mineral wool insulation board with a relative high density and preformed
and therefore self-contained. The mineral wool insulation board is glued to the upper
surface 11 of the reflector dome 4. The edges of the mineral wool insulation board
are preferably provided with a surface treatment to reduce disintegration of the edge
regions. Such surface treatment may include coating or painting with a heat resistant
material.
[0020] Other alternatives are shown in figures 4 to 7, where the layer of mineral wool insulation
5 is arranged in a generally flat shape above the reflector dome 4. As shown in figure
4 to 6, an upper and lower wire mesh 9, 10 are provided on each side of the mineral
wool insulation 5. The upper and lower wire mesh 9, 10 and the mineral wool insulation
layer 5 are sandwiched together and assembled by a treaded fastening assembly 8, preferably
a bolt and a nut with suitably shaped washers. The threated fastening assembly also
connect the assembly (wire mesh 9, 10 and mineral wool insulation 5) to the reflector
dome 4 of the patio heater.
[0021] The embodiment shown in fig. 7 differs from the embodiment shown in figures 4 to
6 only in that the upper wire mesh 9 is replaced by an upper support plate 6.
[0022] In figures 4 to 7, the layer of mineral wool insulation 5 and the supporting wire
mesh 9, 10 and upper support plate 6 are shown in flat configuration. However, it
is realised that the wire mesh 9, 10 and the mineral wool insulation 5 may be formed
to any shape that is desired for the reflector dome 4. Similarly, the outer shape
is shown as square in fig. 6 and 7, but it is realised that it may be cut into any
suitable shape.
[0023] The present invention is described above with reference to some preferred embodiments.
However, it is realised that other variants and equivalent solutions may be provided
without departing from the scope of the invention as defined in the accompanying claims.
1. A patio heater comprising
a base portion adapted to accommodate a heat source,
a heat generator above the base portion, and
a metal reflector dome above the heat generator for reflecting the heat downwards,
characterized in that
a layer of mineral wool insulation is arranged above the reflector dome.
2. A patio heater according to claim 1, wherein the layer of mineral wool insulation
is generally shaped as the reflector dome and is supported by an upper surface of
the reflector dome.
3. A patio heater according to claim 2, wherein an upper support layer is arranged on
top of the layer of mineral wool insulation.
4. A patio heater according to claim 3, wherein the upper support layer is made of a
metal wire mesh.
5. A patio heater according to claims 3, wherein the upper support layer is made of a
metal sheet material.
6. A patio heater according to claim 5, wherein an outer rim of the reflector dome and
an outer rim of the upper support layer are interconnected.
7. A patio heater according to any of claims 2 to 6, wherein the upper surface of the
reflector dome and the layer of mineral wool insulation are bonded together by glue.
8. A patio heater according to any of claims 2 or 6, wherein the reflector dome and the
layer of mineral wool insulation are mechanically fixed to each other, such as by
a threated mounting assembly.
9. A patio heater according to claim 1, wherein the layer of mineral wool insulation
is supported by a lower support layer arranged above the reflector dome.
10. A patio heater according to claim 9, wherein the lower support layer is made of a
metal wire mesh.
11. A patio heater according to claim 9 or 10, wherein an upper support layer is arranged
on top of the layer of mineral wool insulation.
12. A patio heater according to claim 11, wherein the upper support layer is made of a
metal wire mesh.
13. A patio heater according to any of claims 9 to 12, wherein the reflector dome and
the layer of mineral wool insulation are mechanically fixed to each other, such as
by a threated mounting assembly.
14. A patio heater according to any of the preceding claims, wherein the layer mineral
wool insulation has a thickness of between 10 and 100 mm, preferably between 15 and
60 mm, more preferably between 20 and 50 mm.
15. Use of a mineral wool insulation board as a heat shield for a patio heater, wherein
the mineral wool insulation board is arranged above an upper surface of a reflector
dome of the patio heater.