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(11) | EP 3 354 987 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Suction apparatus |
| (57) There is provided a suction apparatus (1) designed to suck up debris (10) comprising
soot (10a) and pellets (10b) from a pellet stove (9) and comprising at least one tank
(2) defining an internal volume (20) suitable to contain the debris (10) and an outlet
hole (21), a suction channel (3) defining a suction direction (3a) and a suction section
(3b) at least as wide as the outlet hole (21), in fluidic through connection with
the tank (2), in a resolvable manner, and suitable to allow the debris (10) to be
channelled towards the tank (2), a filtering device (4) suitable to be placed, in a resolvable manner, in fluidic through connection with the tank (2) and the suction channel (3) therebetween
so as to occupy the suction section (3b), wherein the device (4) comprises a container
(40) that is open in the vicinity of the suction channel (3), extending along the
suction direction (3a) so as to provide a second internal volume (40c) and including
a guide (41), wherein the container (40) comprises side walls (40a) and at least one
bottom wall (40b) consisting of a mesh which is only suitable to allow the passage
of the soot (10a), wherein the guide (41) defines, within the internal volume (40c),
a helical channel so as to convey the pellets (10b) towards the bottom wall (40b)
in a controlled manner, and wherein the bottom wall (40b) is removable on command
with respect to the side walls (40a) so as to release the pellets (10b).
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[0001] The present invention relates to a suction apparatus of the type specified in the preamble of the first claim.
[0002] In particular, the present invention relates to a suction apparatus suitable to be used for cleaning pellet stoves.
[0003] As is known, pellet stoves are apparatuses generally consisting of at least one casing made of cast iron, ceramic or steel and used for heating domestic environments.
[0004] Such apparatuses are fed with pellets, i.e. a fuel obtained from dried sawdust, which is housed inside the casing or feed tank.
[0005] Pellets have the shape of a small cylinder consisting, as said, of pressed sawdust, which is burned inside the tank.
[0006] In order to maintain high efficiency, once the pellets in the tank have been consumed, it is always advisable to clean the tank thoroughly before inserting other pellets.
[0007] Alternatively, the cleaning can be conveniently planned after a suitable amount of fuel loading and reloading cycles to maintain the stove in optimal condition. Generally, common aspirators suitable to remove the soot or debris from the containment tank are used to clean the inside of the casing, so as to clear the volume occupied by the soot and only allow combustion of the pellets.
[0008] Therefore, these aspirators consist of a bin containing the sucked-up debris and of a suction pipe suitable to channel the debris into the containment bin.
[0010] In particular, normal aspirators also tend to suck up debris including unburned or only partially burned pellets, and therefore some of these materials are substantially wasted.
[0011] Different-concept aspirators are described, for example, in patent applications GB-A-421664, US-A-3736728, US-A-3951630 and US-A-920318.
[0012] Documents GB-A-421664 and US-A-920318 describe aspirators comprising a containment casing provided with a removable collection basket. This collection basket is then used to collect the solid debris and, in principle, to separate it from much smaller debris such as dust.
[0013] Documents US-A-3736728 and US-A-3951630, instead, comprise mesh sleeves into which the debris is sucked, which debris is to be deposited on the bottom of a tank by means of the sleeve and separated from the dusty debris by sucking the sleeve from the inside towards the outside.
[0016] In particular, the arrangement of basket-like or tubular elements inside the tank may generate situations in which the debris does not separate regularly and obstruction or plug-effect areas are created in which soot aggregates block the suction.
[0017] In fact, suction difficulty is caused by uncontrolled movements of the larger solid parts such as the pellets, which, due to the circular and whirling motion inside the tank, are in an entropic state such as to produce turbulent movements.
[0018] In the latter case, the pellets can even be expelled from the suction nozzle in a disruptive manner or contrary to the desired effects.
[0019] Moreover, once all the contents have been sucked out, it is necessary to switch the devices off and, when possible, remove the baskets or the sleeves from the tanks. As regards the baskets, it is possible to collect the pellets inside the baskets, but it is not possible to pour them in a controlled manner and neither can it be ascertained that the dust does not fall down outside the collection bin.
[0020] As regards the sleeves, it is even more complex to perform the emptying operations in a clean way since the dust could be transported towards the bottom by the solid debris.
[0021] In this context, the technical task underlying the present invention is to devise a suction apparatus, which is capable of substantially obviating at least some of the above-mentioned drawbacks.
[0022] Within the scope of said technical task, a major object of the invention is to obtain a suction apparatus which allows the soot to be removed from a pellet stove, or the like, in a controlled manner while minimizing the waste of pellets remaining in the tank in a controlled manner.
[0023] Another important object of the invention is to provide a suction apparatus, which also allows the cleaning, maintenance and possibly pellet collection operations to be performed in a controlled and clean manner.
[0024] The technical task and the specified objects are achieved by means of a suction apparatus as claimed in the appended claim 1.
[0026] The features and advantages of the invention will be apparent from the detailed description of preferred embodiments of the invention, with reference to the accompanying drawings, in which:
Fig. 1 shows a suction apparatus according to the invention;
Fig. 2 shows a detail of the suction apparatus according to the invention;
Fig. 3 is an exploded view of a filtering device contained in the suction apparatus according to the invention;
Fig. 4 shows a top view of the filtering device illustrated in Fig. 3;
Fig. 5 is a second example of a filtering device contained in the suction apparatus according to the invention;
Fig. 6 shows a detail of the suction apparatus according to the invention;
Fig. 7 shows the constraint means between the filtering device and the suction channel;
Fig. 8a shows a first view of the detail in Fig. 6;
Fig. 8b shows a second view of the detail in Fig. 6;
Fig. 9 shows a first example of control means for controlling the filtering device contained in the suction apparatus according to the invention;
Fig. 10 shows a second example of control means for controlling the filtering device contained in the suction apparatus according to the invention;
Fig. 11 shows a third example of control means for controlling the filtering device contained in the suction apparatus according to the invention;
Fig. 12 shows a fourth example of control means for controlling the filtering device contained in the suction apparatus according to the invention;
Fig. 13 shows a fifth example of control means for controlling the filtering device contained in the suction apparatus according to the invention;
Fig. 14 shows a sixth example of control means for controlling the filtering device contained in the suction apparatus according to the invention.
[0027] In the present document, the measures, values, shapes and geometric references (such as perpendicularity and parallelism), when associated with terms like "about" or other similar terms such as "almost" or "substantially", are to be understood as unless measurement errors or inaccuracies due to production and/or manufacturing defects and, especially, unless a slight difference from the value, measure, shape, or geometric reference with which it is associated. For example, such terms, if associated with a value, preferably indicate a difference not exceeding 10% of the value itself.
[0028] Furthermore, when used, terms such as "first", "second", "higher", "lower", "main" and "secondary" do not necessarily identify an order, a priority relationship or a relative position, but can simply be used to distinguish more clearly the different components from each other.
[0029] The measurements and the data reported in this text are to be considered, unless otherwise indicated, as carried out in the International Standard Atmosphere ICAO (ISO 2533).
[0030] With reference to the Figures, the suction apparatus according to the invention is indicated as a whole by the numeral 1.
[0031] The suction apparatus 1 may be a common soot-sucking bin 1 used for the suction of debris 10 from a pellet stove 9.
[0032] The pellet stove 9 is a stove known in the current state of the art and comprising a tank or a containment casing inside which the pellets, i.e. pressed chipboard stubs, are burned.
[0033] The debris 10 inside the pellet stove 9 can be of various kinds and may include soot 10a and pellets 10b.
[0034] Soot 10a is the dusty or particulate residue of burned substances, whereas the pellets 10b may comprise unburned or only partially burned pellets.
[0035] The apparatus 1 then comprises suction means, which can comprise an electric motor for the suction of the debris 10. These suction means are of the type known to the person skilled in the art and very common. For this reason they are not described or shown in this patent.
[0036] In addition, the suction means do not affect the innovative features of the apparatus 1 according to the invention and can be of any type.
[0037] Essentially, the apparatus 1 therefore preferably comprises at least one tank 2 and a suction channel 3.
[0038] The tank 2 may consist of an actual bin suitable to contain objects therein. Preferably, the tank 2 defines an internal volume 20 adapted to contain the debris. This internal volume 20 can be of any shape or size and is accessible by means of at least one outlet hole 21.
[0039] Therefore, the outlet hole 21 is included in the tank 2 and is suitable to put the internal volume 20 of the tank 2 in communication with the outside, and more preferably with the suction channel 3.
[0040] The suction channel 3 is preferably a tubular element able to channel a fluid and a certain amount of debris 10 in a specific direction.
[0043] The suction direction 3a is preferably defined by the direction of conveyance of fluids and debris 10. The suction section 3b coincides, for example, with the section of the suction channel 3 along at least one of the ends of the channel.
[0044] Preferably, the suction section 3b is at least as wide as the outlet hole 21 so as to allow the suction channel 3 to be placed in fluidic through connection with the tank 2.
[0045] In particular, the suction channel 3 and the tank 2 are in fluidic through connection so as to allow the suction channel to channel the debris towards the tank 2.
[0047] The coupling portion 30 is the portion arranged in the proximity of the tank 2 and defining the suction section 3b.
[0048] This coupling portion 30 can be resolvably constrained to said tank 2 at the outlet hole 21 so as to provide the fluidic through connection.
[0049] The suction portion 31, instead, is the portion that is not adjacent to the tank 2 and adapted to be inserted, for example, inside the pellet stove to collect the debris 10. It may comprise a converging nozzle suitable to concentrate the suction flow in a central portion of the suction channel 3.
[0051] The filtering device 4 is resolvably constrained to the tank 2 and adapted to be placed in fluidic through connection both with the tank 2 and with the suction channel 3.
[0052] In addition, preferably, the device 4 is arranged between the suction channel 3 and the tank 2 along the suction direction 3a. In particular, this arrangement is adapted to allow the filtering device 4 to occupy the suction section 3b.
[0054] The container 40 is preferably a container that is open in the vicinity of the suction channel 3. The container 40 thus extends along the suction direction 3a so as to provide a second internal volume 40c.
[0055] Therefore, the second internal volume 40c is preferably an extension portion of the suction channel 3 contained inside the device 4.
[0057] The container 40, in turn, preferably comprises side walls 40a and at least one bottom wall 40b.
[0058] The side walls 40a are preferably walls adjacent to the suction channel 3. They are preferably arranged around the suction direction 3a.
[0059] The bottom wall 40b is arranged at the bottom with respect to the suction direction 3a, i.e., is arranged not adjacent to the suction section 3b and so as to close the second internal volume 40c inside the device 4.
[0060] Preferably, the bottom wall 40b is skewed with respect to the suction direction 3a. Both the walls 40a, 40b preferably consist of a mesh suitable to allow the passage of soot 10a and to obstruct the passage of the pellets 10b.
[0061] In particular, the container 40 can be an open cylinder in which the side walls 40a form the side surface and the bottom wall 40b forms a base surface.
[0062] In this case, preferably, the outlet hole 21 is also circular and of a size equal to or greater than the bottom wall 40b.
[0063] In this way, the device 4 can be inserted and extracted through the outlet hole 21. The filtering device 4 thus preferably comprises a collar 42.
[0064] The collar 42 is preferably adjacent to the side walls 40a. Moreover, it is larger than the outlet hole 21 and arranged in the vicinity of the open portion of the container 40. This allows the container 40 to be placed near the outlet hole 21 and the second internal volume 40c to be included within the internal volume 20.
[0065] This configuration is advantageous in that if the internal volume 20 were included inside the suction channel 3, blocking effects affecting the suction flow could occur. The collar 42 may only be supported by the tank 2 and be constrained by means of the suction channel 3.
[0066] Preferably, the collar 42 is resolvably constrained to the tank 2. This constraint can be ensured by a plurality of known constructional solutions such as the common mechanical joints. For example, the collar 42 can be constrained to the tank by means of bolts or a threaded guide or resolvable joints or the like.
[0067] Also preferably, the suction channel 3 can be constrained, as already mentioned, to the tank 2 by means of the coupling portion 30.
[0069] In order to ensure the constraint between the suction channel 3 and the collar 42, the collar preferably comprises protruding members 42b and the coupling portion 30 comprises second guides 30a.
[0070] In detail, preferably, the second guides 30a are suitable to trap at least some of the protruding members 42b when the suction channel 3 is rotated around the suction direction 3a with respect to the device 4.
[0071] The protruding members 42b and the second guides 30a as described may correspond to pins comprising a spherical end that can be inserted inside the second guides 30a. Therefore, the second guides 30a may consist of one or more holes which are compatible with the protruding members 42b connected to tracks of reduced dimensions suitable to trap the spherical end therein, as shown in Fig. 4.
[0072] These types of connections are already known in the current state of the art and allow quick coupling and release for optionally removing the device 4 from the tank 2.
[0073] However, these connections have no limitations since, differently from above, the apparatus 1 may comprise a configuration in which the suction channel 3 is constrained to the device 4.
[0074] That is, for example, the suction channel 3 may comprise protruding members 42b, and vice versa, the collar 42 may comprise the second guides 30a.
[0075] Well-known alternative mechanical constraints can also be provided, such as, for example, described above for the constraint between the device 4 and the tank 2. In addition, but not necessarily, the collar 42 comprises a gasket 42a.
[0076] The gasket 42a is preferably suitable to provide a sealed joint to the suction channel 3. Therefore, it is, for example, a rubber ring or other elastic elements which form said sealing when compressed between the suction channel and the collar 42. The collar 42 may also optionally comprise a second gasket to guarantee the seal with the tank 2.
[0077] As said, the collar 42 is preferably adjacent to the side walls 40a. It can be directly constrained thereto, or in one piece or, alternatively, separate therefrom.
[0078] In the latter case, the container 40 preferably comprises at least one shoulder 40d. The shoulder 40d may be a frame arranged around the container 40 at the opening, or else a plurality of shoulders 40d consisting of tabs may be provided.
[0079] The shoulder 40d is adapted to allow the container 40 to rest on the collar 42 via a resolvable constraint. The collar 42 may thus comprise a housing for the container 40, or else the container 40 may adhere to the outer surface of the collar 42 by means of the shoulder 40d so as to be constrained when the suction channel 3 is connected to the collar 42.
[0080] The collar 42 preferably also comprises a visible portion 42c. The visible portion 42c is, for example, defined by a portion of the collar 42 adjacent to the tank 2. It is therefore made of a transparent material so as to allow a user to view at least part of the device 4 when the apparatus 1 is activated, i.e. in operation.
[0082] The guide 41, included in the container 40, preferably defines, within the internal volume 40c, a channel extending helically along the suction direction 3a so as to convey the pellets 10b towards the bottom wall 40b in a controlled manner.
[0083] The guide 41 can be achieved in a plurality of ways. For example, it is achieved by means of at least one element selected from central walls 41a and a coil 41b.
[0084] In detail, the central walls 41a are walls that are skewed with respect to the side walls 40a and constrained thereon so as to form a helical path.
[0085] These central walls 41a can extend around a through channel consisting of a mesh, and may consist of a mesh.
[0086] In addition, these walls may be continuous, thus forming a complete helicoid, or discontinuous and have spacings so as to form a plurality of successive segments or fins along the trajectory of a helicoid.
[0087] The spacing between said segments can be, for example, 1 cm long. This configuration can increase the flow rate of the pellets 10b by increasing the suction flow, yet still leaving the pellets 10b trapped inside the guide 41.
[0089] The bottom wall 40b, adjacent to the side walls 40a, can thus be constrained thereto, for example in one piece therewith, or may be available adjacent to the side walls 40a, so as to provide the container 40, and removable on command with respect to the side walls 40a.
[0090] This allows a user to clear the device 4 of any pellets 10b trapped inside the container 40, in this case the second internal volume 40c.
[0092] The control means 5 are accessible in the vicinity of the open portion of the container 40 and suitable to move the bottom wall 40b towards or away from the side walls 40a.
[0093] This action can be performed by a plurality of mechanisms, for example a known mechanical mechanism of the lever type. Alternatively, it can take place in opposition to opposing means 6.
[0095] The lever 50 is preferably arranged and movable along the suction axis 3a and at least partially constrained to the bottom wall 40b so as to move at least part of the bottom wall 40b integrally with the movement of the lever 50.
[0096] Therefore, the lever 50, for example, is substantially a bar arranged in the axial portion of the container 40.
[0097] In the second case, a lever 50 can still be provided and the opposing means 6 may comprise at least one elastic member 60.
[0098] The elastic member 60 is preferably suitable to oppose the movement of the lever 50 along the suction axis 3b with respect to an initial condition in which the bottom wall 40b is adjacent to the side walls 40a and obstructs the outflow of the pellets 10b from the device 4.
[0099] Therefore, the elastic member 60 is capable of autonomously restoring the adjacency between the side walls 40a and the bottom wall 40b.
[0100] In any case, the mechanism for totally or partially moving away the bottom wall 40b is to be considered as a modifiable component according to what is known in the current state of the art. Other embodiments can be contemplated taking into account that the container 40 is substantially shaped like a collection basket provided with a guide 41 whose bottom can be opened and closed.
[0102] For example, the bottom wall 40b can be transiently constrained to the side walls 40a at a single point so as to be only partially moved away from the side walls 40a by means of the lever 50, which can be activated with or without the opposition of opposing means 6.
[0103] Alternatively, release means may also be provided near the bottom wall 40b, such as, for example, a handle in the external portion with respect to the second internal volume 40c of the bottom wall 40b suitable to allow the bottom wall 40b to be at least partially moved away from the side walls 40a by resolving a constrained joint that can be restored when the release of the pellets 10b is completed, or in opposition to opposing means 6 with automatic closure of the container 40 once the emptying is completed and the handle is released.
[0104] Therefore, the methods for opening the bottom wall 40b are also not to be considered as limiting the invention.
[0105] As regards the materials, by way of example, the apparatus 1 has materials known in the current state of the art. For example, the tank may be metallic, the suction channel may be polymeric, and the device 4 may comprise a metal mesh, both for the container 40 and for the guide 41.
[0106] The collar 42 may also be metallic or polymeric, and the visible portion 42c may comprise glass or transparent polymeric material.
[0107] From a dimensional point of view, the casing 40 may be a cylinder 15 cm in height with a diameter that varies according to the outlet hole 21. In the same way, the collar 42 can be a ring with a diameter larger than the outlet hole 21.
[0110] Once activated, the debris 10 is drawn into the suction channel 3, which conveys the debris substantially along a suction direction 3a. When the debris 10 is conveyed inside the device 4, it separates into soot 10a and pellets 10b. The soot is sucked out of the mesh forming the side walls 40a, whereas the pellets 10b move inside the guide 41 following a controlled helical route or path.
[0111] Therefore, the device 4 is capable of separating the debris 10 and cleaning up the pellets 10b without the onset of blocking or plugging effects in the suction channel 3.
[0112] When the pellets 10b collected by the device 4 fill the latter entirely, the user, who can view this phenomenon thanks to the visible portion 42c, can deactivate the apparatus 1, easily disengage the suction channel 3 through a simple rotation around the suction axis 3a and remove the device 4.
[0113] The device 4 can then be emptied, in this case too in a controlled manner, by overturning or by using the control means 5 which move the bottom wall 40b away from the side walls 40a.
[0115] In fact, the apparatus 1, by conveying the pellets inside the device 4, prevents the latter from introducing into the tank 2 an entropic and turbulent motion with a drastic decrease in efficiency on the part of the apparatus 1.
[0116] When the pellets 10b enter the suction channel 3, they follow the suction direction 3a until they enter the guide 41 where they are not moved by the flows inside the tank 2, but are guided in a controlled manner to the bottom wall 40b.
[0117] The fact of being arranged helically, in conjunction with the mesh comprised by the container 40, allows the pellets 10b and the device 4 to be completely cleared of the soot 10a.
[0118] In addition, the positioning of the second internal volume 40c inside or almost totally inside the tank 2 avoids the generation of plug-effects which, conversely, would occur in devices arranged in the suction channel 3.
[0119] Lastly, the device 4 is extremely versatile and also allows its arrangement in different-concept apparatuses, provided they have an outlet hole 21.
[0120] The invention is susceptible of variations falling within the scope of the inventive concept as defined by the claims.
[0121] For example, the collar 42 can comprise portions that are adjustable for the arrangement of the device 4 on a plurality of outlet holes 21 of different diameter. In this context, all details are replaceable by equivalent elements and the materials, shapes and dimensions may be any materials, shapes and dimensions.
1. A suction apparatus (1) suitable to suck up debris (10) comprising soot (10a) and
pellets (10b) from a pellet stove (9) and comprising at least
- a tank (2) defining an internal volume (20) suitable to contain said debris (10) and an outlet hole (21),
- a suction channel (3) defining a suction direction (3a) and a suction section (3b) at least as wide as said outlet hole (21), in fluidic through connection with said tank (2), in a resolvable manner, by means of said outlet hole (21) and adapted to allow said debris (10) to be channelled towards said tank (2),
- a filtering device (4) resolvably constrained to said tank (2) and suitable to be
placed, in a resolvable manner, in fluidic through connection with said tank (2) and
said suction channel (3) between said tank (2) and said suction channel (3) along
said suction direction (3a) so as to occupy said suction section (3b),
And said apparatus being characterised in that
- said filtering device (4) comprises a container (40) that is open in the vicinity of said suction channel (3), extending along said suction direction (3a) so as to provide a second internal volume (40c) and including a guide (41),
- said container (40) comprising side walls (40a) and at least one bottom wall (40b) with respect to said suction direction (3a) consisting of a mesh which is suitable to allow the passage of said soot (10a) and obstruct the passage of said pellets (10b),
- said guide (41) defining, within said internal volume (40c), a channel extending helically along said suction direction (3a) so as to convey said pellets (10b) towards said bottom wall (40b) in a controlled manner.
2. An apparatus (1) according to claim 1, wherein said guide (41) is achieved by means
of at least one element selected from central walls (41a) and a coil (41b), said central
walls (41a) being skewed with respect to said side walls (40a) and constrained to
said side walls (40a), and said coil (41b) being a closed tubular channel defined
by a mesh.
3. An apparatus (1) according to at least one of the preceding claims, wherein said bottom
wall (40b) is removable on command with respect to said side walls (40a) so as to
release said pellets (10b) trapped inside said second internal volume (40c).
4. An apparatus (1) according to claim 1, comprising control means (5) accessible in
the vicinity of the open portion of said container (40) and suitable to move said
bottom wall (40b) towards or away from said side walls (40a) in opposition to opposing
means (6).
5. An apparatus (1) according to at least one of the preceding claims, wherein said control
means (5) comprise a lever (50) arranged and movable along said suction axis (3a)
and at least partially constrained to said bottom wall (40b) so as to move at least
part of said bottom wall (40b) integrally with the movement of said lever (50).
6. An apparatus (1) according to at least one of the preceding claims, wherein said opposing
means (6) comprise at least one elastic member (60) suitable to oppose the movement
of said lever (50) along said suction axis (3b) with respect to an initial condition
in which said bottom wall (40b) is adjacent to said side walls (40a) and obstructs
the outflow of said pellets (10b) from said device (4).
7. An apparatus (1) according to at least one of the preceding claims, wherein said container
(40) is an open cylinder in which said side walls (40a) form the side surface and
said bottom wall (40b) forms a base surface, said outlet hole (21) being circular
and of a size equal to or greater than said bottom wall (40b), and said filtering
device (4) comprising at least one collar (42) adjacent to said side walls (40a) and
larger than said outlet hole (21) in the vicinity of the open portion of said container
(40) so as to allow said container (40) to rest in the vicinity of said outlet hole
(21) and said second internal volume (40c) to be comprised inside said internal volume
(20).
8. An apparatus (1) according to at least one of the preceding claims, wherein said collar
(42) is resolvably constrained to said tank (2) in the vicinity of said outlet hole
(21) by means of mechanical joints selected from bolts, threaded guides and resolvable
joints.
9. An apparatus (1) according to at least one of the preceding claims, wherein said suction
channel (3) comprises a coupling portion (30) and a suction portion (31), said coupling
portion (30) being suitable to be resolvably constrained to one element selected from
said tank (2) in the vicinity of said outlet hole (21) and said collar (42).
10. An apparatus (1) according to at least one of the preceding claims, wherein said collar
(42) comprises a gasket (42a) and protruding members (42b) and said coupling portion
(30) comprises second guides (30a), said second guides (30a) being suitable to trap
at least some of said protruding members (42b) when said suction channel (3) is rotated
along said suction direction (3a) with respect to said device (4), and said gasket
(42a) being adapted to provide a sealed joint to said suction channel (3).
11. An apparatus (1) according to at least one of the preceding claims, wherein said container
(40) is separate from said collar (42) and comprises at least one shoulder (40d) suitable
to allow said container (40) to rest on said collar (42) via a resolvable constraint.
12. An apparatus (1) according to at least one of the preceding claims, wherein said collar
(42) comprises at least one visible portion (42c) made of a transparent material so
as to allow a user to view at least part of said device (4) when said apparatus (1)
is activated.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description