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(11) | EP 1 672 279 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Gas flow tap for a gas burner |
| (57) Gas flow tap for a gas burner that comprises a flow control member (1) rotated by
a shaft (2), which is movable axially in a first direction (D1), and a safety valve
(3) that includes a regulation element (4) movable in a second direction (D2). A movement
transfer device (40) is adapted to convert a displacement of the shaft (2) in the
first direction (D1) into a displacement of an intermediate member (10) in the second
direction (D2) inside a conduit (11), with said intermediate member (10) pushing the
regulation element at the same time (4) in this second direction (D2), to its open
position. The movement transfer device (40) includes a pair of inclined conical surfaces
(12, 13) connected to the shaft (2) and the intermediate member (10) in mutual contact.
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Technical field
[0001] This invention relates to a gas flow tap for a gas burner, and more particularly to a gas flow tap of the type that comprises a flow control member operated manually in order to control the flow of gas through the tap and a safety valve operated by an electromagnet fed by a thermocouple to keep the regulation element open only when the presence of a flame is detected.
Prior art
[0002] A conventional gas tap comprises a member that defines an internal conduit from a gas inlet to a gas outlet, and a flow control member to control the flow of gas through said internal conduit. This flow control member includes a rotatable member connected to a shaft that can be rotated manually by a user between closed and open positions. The flow of gas increases or decreases gradually as the flow control member is rotated and this can be disposed in any intermediate position in order to select the required gas flow. In known arrangements gas taps of this type are applied to a gas conduit for a burner, and also incorporate a safety valve with a regulation element pushed by a spring to a closed position against a ring-shaped seating, and an electromagnet fed by a thermocouple to keep the regulation element in an open position thereby overriding the effect of said spring only while the presence of a flame in said burner is detected. The aforementioned safety valve can be disposed either upstream or downstream of the flow control element although it is preferably positioned upstream for greater safety. In order to light the burner the regulation element of the safety valve must be opened manually to allow gas to flow to the burner and must be kept in the open position manually until the flame heats the thermocouple to feed the electromagnet.
[0003] In patent GB-A-2196732 there is disclosed a gas tap of the type described above which includes a spindle movable axially in a first direction parallel to the drive shaft of the flow control member, and substantially perpendicular to a second direction of displacement of the regulation element of the safety valve. The drive shaft of the flow control member can also be moved axially manually, and a mechanism transmits its movement to said spindle in order to move it. On one end of the spindle there is a conical configuration disposed in order to push an additional conical configuration positioned on one end of an intermediate member adapted to slide in said second direction and disposed in order to push the regulation element with its other end by contact with a central part on it thereby overriding the effect of the aforementioned spring. This intermediate pusher member includes at least one longitudinal passageway to allow gas to flow through it.
[0004] Patent GB-A-2242257 describes a gas tap with a safety valve in which the drive shaft of the flow control member is movable axially in a first direction substantially perpendicular to a second direction in which the regulation element of the safety valve is moved. This tap includes a movement transfer device based on an elastic member deformed by a displacement of said shaft in the first direction. This deformation causes the elastic member to lengthen in the aforementioned second direction thereby causing a displacement of the regulation element against the action of the corresponding spring. The elastic member has one fixed end and another free end that moves in the second direction and in direct contact with the regulation element. Between both ends, the elastic member includes a zone adapted to be pressed and deformed by a displacement of the shaft.
[0005] However, none of the aforementioned documents disclose or suggest a gas tap of the type described herein which includes a movement transfer device in which the regulation element of the safety valve is pushed by a displacement in the second direction of a sliding intermediate member which is pushed directly at the same time by an axial displacement in the first direction of the drive shaft of the flow control member or by a member in the movement transfer device in contact with the drive shaft of the control member.
Disclosure of the invention
[0006] This invention provides a gas flow tap for a gas burner, of the type that comprises a flow control member rotated by a shaft, which is also movable axially in a first direction through said flow control member; a safety valve disposed upstream or downstream of the flow control member, which includes a regulation element fitted onto a spindle movable axially in a second direction, different to the first, a first spring disposed to push said regulation element to a closed position against a ring-shaped seating, and an electromagnet fed by a thermocouple to keep the regulation element in an open position thereby overriding the effect of said first spring; and a movement transfer device adapted to convert a displacement of said shaft in the aforementioned first direction into a displacement of said spindle in the aforementioned second direction. The inventive gas tap is characterised in that said movement transfer device comprises an intermediate member adapted to slide in the second direction, aligned with the spindle inside a conduit disposed downstream or upstream of said ring-shaped seating, with said intermediate member having a first end disposed to be pushed by the shaft or by a member in the movement transfer device in contact with the shaft, a second end disposed to push the regulation element through contact with a central part on it thereby overriding the effect of the aforementioned spring, and at least one longitudinal passageway to allow gas to flow through said conduit.
[0007] In accordance with a first example of the embodiment, the movement transfer device comprises a first conical surface adapted to be pushed by the shaft against an inclined plane, or a second conical surface, formed on said first end of the intermediate member. In accordance with a second example of the embodiment, the movement transfer device comprises an elastic member that has a first end supported on fixed surfaces that prevent its displacement in said first and second directions, a second end adjacent to said first end of the intermediate member and supported on a fixed surface that prevents its displacement in the first direction but allows its displacement in the second direction, and a curved section, between said first and second ends, adapted to be pressed and deformed by a displacement of the shaft, thereby causing a variation in the distance between the first and second ends and a displacement of the second end in the second direction in order to push the first end of the intermediate member.
Description of the drawings
[0008] The foregoing and other features of the invention will be made evident in the light of the following detailed description of an example of the embodiment, reference being made to the accompanying drawings, in which:
Fig. 1 is a cross-sectional view of a gas tap in accordance with a first example of an embodiment of the present invention;
Fig. 1A is an exploded view in perspective of members that comprise a movement transfer device in the gas tap arrangement of Fig. 1;
Fig. 2 is a cross-sectional view of a gas tap in accordance with a second example of an embodiment of the present invention;
Fig. 2A is an exploded view in perspective of members that comprise a movement transfer device in the gas tap arrangement of Fig. 2.
Detailed description of the invention
[0009] With reference firstly to Figs. 1 and 1A, a tap used to conduct gas to a burner according to a first example of an embodiment of the present invention is shown. The gas tap comprises a member 22 that defines an inlet 23 adapted for connection to a gas supply conduit (not shown) and linked to a cavity 25 that houses a safety valve 3. The aforementioned connection between said inlet 23 and said cavity 25 is formed through a derivation that presents an opening 26 in the cavity 25. The aforementioned cavity 25 is linked through a conduit 11 to a housing 24 that houses a flow control member 1. Finally, the aforementioned housing 24 is connected to an outlet (not shown in the figures) adapted for connection to a gas supply conduit for a burner.
[0010] It should be pointed out that the gas circuit through the tap can be reversed, i.e. with the inlet 23 connected directly to the housing 24 of the flow control member 1, with this being connected downstream to the cavity 25 of the safety valve 3 through the conduit 10, and finally, with the cavity 25 being connected to the outlet without this altering the scope of the present invention.
[0011] The aforementioned flow control member 1 is connected to a shaft 2 oriented in a first direction (indicated by an arrow D1), in such a way that a manual rotating of the shaft 2 with a knob (not shown) causes the flow control member 1 to rotate and open and cut-off the gas flow and to control the flow of gas through the housing 24. The aforementioned safety valve 3, which is disposed, in the drawing, upstream from the flow control member 1, includes a regulation element 4 fitted onto a spindle 5 that is movable axially in a second direction (indicated by an arrow D2), different to the first. In general, said second direction D2 is perpendicular to the first direction D1. A first spring 6 is disposed in order to push said regulation element 4 to a closed position against a ring-shaped seating 9 disposed around the opening to the aforementioned conduit 11. A thermocouple heated by the flame of the burner feeds an electromagnet 7 adapted to retain said retracted spindle so as to keep the regulation element 4 in an open position thereby overriding the effect of said first spring 6. If, for any reason the flame of the burner goes out, the thermocouple stops heating the electromagnet 7 and the spring 6 returns the regulation element 4 to the closed position against the ring-shaped seating 9, with the result that the flow of gas to the burner is interrupted even though the flow control member 1 is still open.
[0012] To light the burner, in addition to rotating the flow control member 1 to enable the gas to pass through the housing 24 to the outlet, the regulation element 4 of the safety valve 3 must be opened manually to allow the gas to pass through the conduit 10, and it is also necessary to keep the regulation element 4 in the open position manually until the flame has heated the thermocouple sufficiently for it to feed the electromagnet 7. To enable this the drive shaft 2 of the flow control member 1 can also be moved axially in the first direction D1 through said flow control member 1 without altering either its axial or angular position. The gas tap of the present invention includes a transfer movement device 40 adapted to convert a displacement of said shaft 2 in the first direction D1, to the inside of the member 22, into a displacement of the regulation element 4 in the second direction D2, to its open position.
[0013] In the first example of the embodiment shown in Figs. 1 and 1A, the aforementioned movement transfer device 40 comprises an intermediate member 10 adapted to slide in the second direction D2, aligned with the spindle 5 of the regulation element 4, inside the aforementioned conduit 11, which, in this example, is disposed downstream of said ring-shaped seating 9 and upstream of the housing 24 of the flow control member 1. The aforementioned intermediate member 10 has a first end 10a in which is formed an inclined plane 13 disposed to be pushed by the shaft 2, or preferably, by a first conical surface 12 connected to the shaft 2. A second end 10b of the intermediate member 10 is disposed to push the regulation element 4 by contact with a central part on it through the ring-shaped seating 9 and against the elastic force of the first spring 6.
[0014] The intermediate member 10 also has at least one longitudinal passageway 10c to allow gas to flow through said conduit 11. In the most clearly shown example in Fig. 1A, the intermediate member 10 has a three-armed star-shaped cross-section so that one of said passageways 10c is defined between each two arms. A longitudinal projection 8, parallel to the second direction D2, is defined on the end of each arm of the intermediate member 10, and some grooves 27 are configured in the conduit 11 and act as guides for the projections 8 in order to allow the displacement of the intermediate member 10 and prevent it from rotating. As a result, the inclined plane 13 remains in a suitable position in relation to said first conical surface 12. Alternatively, on said first end 10a of the intermediate member 10 a second conical surface (not shown) adapted to be pushed by the first conical surface 12 connected to the shaft 2 could be formed. In this case, given the axial symmetry of both conical surfaces, the aforementioned projections 8 and grooves 27 could be omitted.
[0015] In the example of the embodiment shown in Figs. 1 y 1A, the transfer movement device 40 comprises a rod 14 adapted to slide in the first direction D1, aligned with the shaft 2, inside a housing 15 formed through the flow control member 1. The aforementioned rod 14 has a first end 14a disposed to be pushed by the second internal end 2b of the shaft 2 and a second end 14b to which said first conical surface 12 facing said inclined plane 13 is connected. Although the first conical surface 12 could be formed directly on said second end 14b of the rod 14, in the example detailed in Figs. 1 and 1A the conical surface 12 is built into a piece 16 fixed to said second end 14b of the rod 14, and through said part 16 passageways 28 are formed to allow the gas to pass through to the inside of the flow control member 1. The shaft 2 is partially introduced into the flow control member 1 and has a first external end 2a onto which a knob (not shown) and a second internal end 2b in contact with the first end 14a of the rod 14 are fitted. Between the flow control member 1 and the first end 14a of the rod 14 is disposed a second spring 17 to push the rod 14 and the shaft 2 to an inactive axial position, i.e. in a direction to the first external end 2a of the shaft 2. In fact, in accordance with a variation of an embodiment not shown, the rod 14 and the shaft 2 form a single part, and the first conical surface 12 is connected to said second internal end 2b of the shaft 2, which projects from the innermost end of the flow control member 1. However, it is preferable that the rod 14 and the shaft 2 are separate parts so that a suitable different material can be selected for each one. It must be pointed out that throughout this document, the term "shaft" is used generically to refer to the unit formed by the shaft 2 and the rod 14, regardless of whether they form part of the same part or are separate parts.
[0016] With reference to Figs. 2 and 2A, a second example of an embodiment of the gas tap of the present invention is shown, where those members that are similar to those of the first example of the embodiment are indicated with the same numerical references. Also in this second example of an embodiment the gas tap comprises a member 22 that defines an inlet 23, a cavity 25 for a safety valve 3, a conduit 11, a housing 24 for a flow control member 1, and an outlet. The numerical reference 26 indicates an opening (represented by dotted lines in Fig. 2) of a derivation that connects the inlet 23 to the cavity 25. It should also be pointed out here that the gas circuit through the tap could be reversed without affecting the object of the present invention.
[0017] Similarly to the first example of the embodiment, the rotating shaft 2 of the flow control member 1 is movable axially in a first direction (indicated by an arrow D1), and the regulation element 4 of the safety valve 3 is fitted onto a spindle 5 that is movable axially in a second direction (indicated by an arrow D2), preferably perpendicular to the first direction D1 and pushed by a first spring 6 to a closed position. A movement transfer device 40 is also built in here adapted to convert a displacement of said shaft 2 in the aforementioned first direction D1 into a displacement of the regulation element 4 in the aforementioned second direction D2, to its open position and an intermediate member 10 adapted to slide in the second direction D2, aligned with the rod 5, inside the conduit 11. The aforementioned intermediate member 10 has a first end 10a disposed to be pushed by a member in the movement transfer device 40 in contact with the shaft 2, which will be described in detail below, and a second end 10b disposed to push the regulation element 4 by contact with a central part on it thereby overriding the effect of the aforementioned spring 6. Preferably the intermediate member has a star-shaped cross-section to provide longitudinal passageways 10c to allow gas to flow through the conduit 11.
[0018] In this second example of the embodiment, the movement transfer device 40 comprises an elastic member 18 that has a first end 18a supported on fixed surfaces 19, 20 of the member 22 that prevent its displacement in said first and second directions D1, D2, and a second end 18b adjacent to said first end 10a of the intermediate member 10 and supported on a fixed surface 21 of the member 22 that prevents its displacement in the first direction D1 but allows its displacement in the second direction D2. The elastic member 18 has a curved section 18c disposed between said first and second ends 18a, 18b, and which is adapted to be pressed and deformed by a displacement of the shaft 2 in the first direction D1, thereby causing a variation in the distance between the first and second ends 18a, 18b and a displacement of the second end 18b in the second direction D2 in order to push the first end 10a of the intermediate member 10, which at the same time pushes the regulation element 4 by contact through the ring-shaped seating 9. As can be seen more clearly in Fig. 2A, the second end 18b of the elastic member 18 is connected to the first end 10a of the intermediate member 10, e.g. by means of a pressure-inserted stud 29.
[0019] Similarly to the first example of the embodiment, the movement transfer device 40 comprises a rod 14 adapted to slide in the first direction D1, aligned with the shaft 2, inside a housing 15 formed through the flow control member 1. However, here the aforementioned rod 14 has a first end 14a disposed to be pushed by the shaft 2 and a second end 14b disposed to press and deform said curved section 18c of the elastic member 18. Between the flow control member 1 and the rod 14 is disposed a second spring 17 to push the rod 14 and the shaft 2 to an inactive axial position, i.e. in a direction to the first external end 2a of the shaft 2. Evidently, a variation of the embodiment (not shown) is also possible here, in which the rod 14 is built into the same part as the shaft 2, which in this case crosses the flow control member 1 so that, in addition to the first external end 2a where the knob is fixed, it has a second internal end 2b projecting out of the flow control member 1 and disposed to press and deform said curved section 18c of the elastic member 18. Logically, here the second spring 17 shall be disposed to push the shaft 2 to the inactive axial position.
1. Gas flow tap for a gas burner, of the type that comprises:
- a flow control member (1) rotated by a shaft (2), and which is also movable axially in a first direction (D1) through said flow control member (1);
- a safety valve (3), disposed upstream or downstream of the flow control member (1), which includes a regulation element (4) fitted onto a spindle (5) movable axially in a second direction (D2), different to the first, a first spring (6) disposed to push said regulation element (4) to a closed position against a ring-shaped seating (9), and an electromagnet (7) fed by a thermocouple to keep the regulation element (4) in an open position thereby overriding the effect of the first spring (6); and
- a movement transfer device (40) adapted to convert a displacement of said shaft (2) in the aforementioned first direction (D1) into a displacement of the regulation element (4) in the aforementioned second direction (D2), to its open position;
characterised in that said movement transfer device (40) comprises an intermediate member (10) adapted to slide in the second direction (D2), aligned with the spindle (5) inside a conduit (11) disposed downstream or upstream of said ring-shaped seating (9), with said intermediate member (10) having a first end (10a) disposed to be pushed by the shaft (2) or by a member in the movement transfer device (40) in contact with the shaft (2), a second end (10b) disposed to push the regulation element (4) by contact with a central part on it thereby overriding the effect of the first spring (6), and at least one longitudinal passageway (10c) to allow gas to flow through said conduit (11).2. Tap according to claim 1, wherein the movement transfer device (40) comprises a first
conical surface (12) adapted to be pushed by the shaft (2) against an inclined plane
(13), or a second conical surface, connected to said first end (10a) of the intermediate
member (10).
3. Tap according to claim 1, wherein said inclined plane (13) is formed on the first
end (10a) of the intermediate member (10), and the intermediate member (10) and the
conduit (11) are configured complementarily to allow the displacement of the intermediate
member (10) preventing it from rotating.
4. Tap according to claim 2 or 3, wherein the movement transfer device (40) comprises
a rod (14) adapted to slide in the first direction (D1), aligned with the shaft (2),
inside a housing (15) formed through the flow control member (1), with said rod (14)
having a first end (14a) disposed to be pushed by the shaft (2) and a second end (14b)
to which said first conical surface (12) facing said inclined plane (13) or second
conical surface is connected.
5. Tap according to claim 4, wherein the first conical surface (12) is formed on said
second end (14b) of the rod (14).
6. Tap according to claim 4, wherein the first conical surface (12) is formed on a part
(16) connected to said second end (14b) of the rod (14).
7. Tap according to claim 2 or 3, wherein the shaft (2) crosses the entire flow control
member (1) and has a first external end (2a) and a second internal end (2b) that projects
out of the flow control member (1), with the first conical surface (12) being connected
to said second internal end (2b) of the shaft (2).
8. Tap according to claim 1, wherein the movement transfer device (40) comprises an elastic
member (18) that has a first end (18a) supported on fixed surfaces (19, 20) that prevent
its displacement in said first and second directions, a second end (18b) adjacent
to said first end (10a) of the intermediate member (10) and supported on a fixed surface
(21) that prevents its displacement in the first direction (D1) but allows its displacement
in the second direction (D2), and a curved section (18c), between said first and second
ends (18a, 18b), adapted to be pressed and deformed by a displacement of the shaft
(2), thereby causing a variation in the distance between the first and second ends
(18a, 18b) and a displacement of the second end (18b) in the second direction (D2)
in order to push the first end (10a) of the intermediate member (10).
9. Tap according to claim 8, wherein the movement transfer device (40) comprises a rod
(14) adapted to slide in the first direction (D1), aligned with the shaft (2), inside
a housing (15) formed through the flow control member (1), with said rod (14) having
a first end (14a) disposed to be pushed by the shaft (2) and a second end (14b) disposed
to press and deform said curved section (18c) of the elastic member (18).
10. Tap according to claim 9, wherein the shaft (2) crosses the flow control member (1)
and has a first external end (2a) and a second internal end (2b) that projects out
of the flow control member (1), with said second internal end (2b) disposed to press
and deform said curved section (18c) of the elastic member (18).
11. Tap according to claim 4 or 9, wherein it comprises a second spring (17) disposed
between the flow control member (1) and the rod (14) to push the rod (14) and the
shaft (2) to an inactive axial position.
12. Tap according to claim 7 or 10, wherein it comprises a second spring (17) disposed
between the flow control member (1) and the shaft (2) to push the shaft (2) to an
inactive axial position.
13. Tap according to any of the previous claims wherein it comprises a member (22) that
defines an inlet (23) adapted for connection to a gas supply conduit and linked to
a cavity (25) that houses said safety valve (3), with said cavity (25) being connected
to the conduit (11) of the intermediate member (10) through the ring-shaped seating
(9), with said conduit (11) being connected to a housing (24) that houses the control
member (1), and with said housing (24) being connected at the same time to an outlet
adapted for connection to a gas supply conduit for a burner.