Abstract:
A gas tap for controlling the flow of a gas to a cooking appliance. In one embodiment, the gas tap includes a body and a rotatable regulation member positioned within the valve body, the valve body having a stationary groove for the inlet of gas from an exterior wall surface to an interior wall surface of the body, the regulation member having a passage opening for the inlet of gas from an exterior surface to an interior cavity of the regulation member, the passage opening moving with an angular rotation of the regulation member. The groove and passage opening are shaped, dimensioned and positioned relative to one another such that the regulation of an intermediate gas flow Qgra (a flow between Qmax and Qmin) is proportional to the angular displacement of the rotatable regulation member.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to PCT/ES2007/070121 filed Jun. 19, 2007, which claims priority to Spanish Patent Application No. U200601861, filed Aug. 7, 2006. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a device for distributing a gas flow to a domestic cooking appliance, which may include a number of rotary taps integrated into the distribution pipe, for regulating the individual gas flow supplied to an outlet conduit of said tap. 
     BACKGROUND 
     There are known gas fuel distributors for a cooking appliance of the type mentioned above, such as that disclosed in WO 97/21960, which comprises various taps integrated in a distribution pipe, distanced from each other, and assembled with means for the airtight closure of the insertion holes on the tap body in the pipe. 
     Each of the gas taps disclosed therein includes a body portion comprising a fixed generally hollow frusto-conical casing positioned within the distribution pipe that has an inlet orifice for the inlet of gas from the distribution pipe. The gas tap also include a frusto-conical rotary plug member located within the casing having both a major orifice and a minor orifice. The plug member is rotatable by means of a control key such that the major and minor orifices of the plug member can be moved into and/or out of varying degrees of alignment with the inlet orifice of the casing to regulate or control the volume of gas flow through an outlet port of the tap. The major orifice is for variation of the gas flow from low to high flame in an associated burner and the minor orifice is for achieving a very low ‘simmer’ flame level. This device for gas distribution presents a problem in that the casing and the rotary plug member have substantially circular passage openings that cannot regulate an intermediate flow “Qgra” proportional to the angular path of the conical member. In addition, the distribution pipe of this known device for gas distribution has two flat opposing walls for the insertion and exit of the tap body, as a result of which the airtight closure of the coupling with the flat walls of the pipe is simple. 
     SUMMARY OF THE DISCLOSURE 
     It is an object of present invention to provide a device for distributing a gas flow to a domestic cooking appliance, preferably with a number of regulation taps inserted between the walls of a common distribution pipe, wherein both the surface of the tap body and a rotary regulation member have passage openings that overlap each other for the regulation of an intermediate flow “Qgra” proportional to the angular displacement of the conical member, between two constant flows, the maximum “Qmax” and the minimum “Qmin”. 
     The passage opening in the tap body and in the rotary regulation member possess contours of a specific shape, such as the ones described in detail in the following section, both passage openings being formed by portions of a surface area adjacent to each other in succession, which cooperate by means of their overlapping in the direction of rotation to create said three flows, the intermediate flow “Qgra” also being variable in a linear manner. 
     In addition, for the purposes of using a cylindrical pipe for the assembly of the distributing device, the invention resolves the problem of the coupling between the tap body and the cylindrical pipe, by means of an airtight closure of both insertion holes on the tap body, which are not flat but which have the geometrical profile of the orthogonal intersection of two cylinders. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a device of one embodiment for distributing gas for cooking with the taps integrated in the distribution pipe. 
         FIG. 2  is a fragmentary view in perspective of the device for distributing gas of  FIG. 1 , showing each part in its relative assembly position. 
         FIG. 3  is a profile view of a conical regulation member of the tap of the device for distributing gas of  FIGS. 1 and 2 . 
         FIG. 4  is a perspective view of a tap body of the device for distributing gas of  FIGS. 1 and 2 . 
         FIG. 5  is a flat view of the tap body of  FIG. 4 , showing its surface developed with a regulation groove. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIGS. 1 to 5 , a device for distributing gas  1  in accordance with one embodiment is illustrated. As shown, the device comprises an elongated gas distribution pipe  2 , preferably cylindrical, of the type that is connected at one end to a gas source of a domestic cooking appliance, and a number of rotary taps  3  integrated into the distribution pipe  2  that are distanced from each other for the individual supplying of a gas flow “Q” to a corresponding burner. 
     Each of taps  3  comprise a tap body  4  and a internal regulation member  5  that may be conical, the part of the body  4   a  that cooperates with the regulation of the gas flow “Q” being housed inside the pipe  2 . The gas supplied by the source circulates through the inlet hole  2   b  of the pipe  2 , and reaches the tap  3  first of all through a regulation groove  11  on the surface of the body  4   a , and then through a rotary passage opening  12  towards the interior of the conical member  5 , from where the gas is led to an outlet conduit  3   b  in the tap body. Outside the distribution pipe  2 , a nozzle  8  is threaded to the outlet end  4   c  of the tap for injecting the regulated flow “Q” to the intake of the mixture of the corresponding burner. 
     The gas flow “Q” circulating through the pipe  2  is distributed between the various integrated taps  3 , each of them being capable of supplying, in this order, a maximum flow Qmax, an intermediate flow Qgra, and a minimum flow Qmin, by rotating the shaft  6  of the tap. 
     The conical member  5  is coupled to the drive shaft  6 , the coupling of both to the tap body  4  being covered by a cap  7  which guides the rotation of the shaft  6  between two stops of an angular path of preferably 270° ( FIG. 5 ). The conical member  5  is disposed inside the body  4 . In one embodiment a spring  24  is provided as a biasing force that continually urges the conical member  5  into the interior of the valve body  4  as shown in  FIG. 1 . A flap  26  in the shaft  6  which is configured to engage with a recess  25  in the regulation member  5  enables a rotation of the shaft  6  to induce a rotation of the regulation member  5 . A passage opening  12  is provided within the rotatable regulation member  5  and moved with it, whereas a stationary elongated groove  11  is provided in the wall  4   a  of the tap body  4 . The passage opening  12  is moveable between two angular positions P 0 -P 3  relative to the body  4  in order to supply said flows Qmax, Qgra and Qmin. 
     In one embodiment, the body  4  of the tap  3  comprises three substantially cylindrical body parts  4   a ,  4   b  and  4   c  of different diameters forming sections  9  and  10  in the axial direction towards the pipe  2 , the intermediate part  4   a  forming a cylindrical wall that contains the stationary regulation groove  11  and which is inserted into the pipe intake hole  2   b  through a hole  13  in the cylindrical wall of the pipe  2   a . This intermediate part of the body  4   a  has a machined internal hollow space with a conical surface  40 , inside which the conical member  5  is fitted, pushed by the spring  24 . 
     The first part  4   b  of greater diameter is outside the pipe  2 , and forms a cross-section  9  as an insertion limit in the pipe  2 , out of which axially project two arched lobes  15  with a transverse edge surrounding the hole  13  in the cylindrical wall of the pipe  2   a , the shape of which follows the geometric line of intersection with a cylinder, thereby enabling its orthogonal coupling to the cylindrical wall of the pipe  2   a . An airtight seal  22  of a specific shape is interposed with the cylindrical wall of the pipe  2 , upon said transverse edge of these lobes  15 , thereby surrounding the hole  13  in the pipe, through which the body  4  passes to ensure its airtight closure. The airtight seal  22  has a recess, on one of its faces, configured with a geometric surface equivalent to the intersection of two cylinders of different diameter, that of the intermediate part  4   a  of the inserted body, and that of the pipe  2 , and it has a flat surface, on the other face, for its tightening against said cross-section  9 , which is also flat. The external part of the body  4   b  has two pairs of peripheral ribs  27  that face each other, in which is connected a respective flap of the cover  7  to ensure the positioning and guidance of the cover  7  with the tap. 
     Part  4   c  of the body is a body end  16  with an external thread for fixing said injector nozzle  8  from the outside of the pipe  2 . The body end  16  forms a second cross-section  10  in the body, being disposed inside the gas intake hole  2   b , from which is created an outlet pipe  3   b  of the tap of flow “Q” which projects out of the pipe  2  for fixing the nozzle  8 . The latter has a nut  17  for its coupling to the cylindrical wall of the pipe  2 , and an injector hole  18  on the free end to supply the mixture fuel intake to the corresponding burner. An adaptor casing  19  and an airtight seal  23  ( FIG. 2 ) are assembled between the pipe  2  and the nut  17  of the nozzle, the shapes of which are designed for the closure against the cylindrical wall of the pipe  2 . The adaptor casing  19  has a cylindrical surface  20 , preferably concave, on the side of the coupling to the pipe  2 , inside of which the airtight seal  23  is fitted, and on the opposite side, the surface  21  of the adaptor casing  19  is flat, in order to make an uniform tightening contact against the flat surface  17  on the nozzle. The airtight seal  23  has a curved concave surface geometrically adapted to the intersection of the cylindrical body  4  with the hole  14  of the pipe  2 , which is also cylindrical. The adaptor casing  19  may also have a different shape to the one described, for example with the curved face  20  in the shape of a semi-spherical lobe, which enters the central hole of the airtight seal  23 , tightening it uniformly against the hole  14  in the pipe  2 . 
     With reference to  FIGS. 4 and 5 , the regulating groove  11  located within the wall  4   a  of the body  4  is stationary, and has a contour formed by two passage areas  11   a  and  11   b  that are different to each other. One passage area  11   a  of a considerable size regulates the flow “Qmax” and preferably has an approximately rectangular shape with two opposite rounded sides to enable its machining, for example of a length “Xm” of around 3 mm and a height “H” of around 6 mm, and also enabling the adjustment of the relative position between conical surfaces  40  and  50 . Next to the passage area  11   a  of considerable size for the Qmax, a convergent groove  11   b  is adjacently formed, the passage area  11   b  of which is narrow and long and extends in the direction of rotation “R” of the conical member  5 , as a result of which it regulates linearly the intermediate flow Qgra. In one embodiment, the widest end of the convergent groove  11   b  is around 1.1 mm and the length “Xg” of the convergent groove  11   b  is around 15 mm which is equivalent to an angular path of approximately 180°. The end of the convergent groove  11   b  provides the minimal flow Qmin. 
     With reference to  FIG. 3 , the conical regulation member  5  comprises said passage opening  12  that overlaps in its rotation over the regulating groove  11  located within the wall  4   a  of the body  4 . This passage opening  12  has a contour that cooperates in the regulation of the various flows “Q” supplied by the tap  3 . The passage opening  12  comprises two portions of different size  12   a  and  12   b  that are located adjacent to each other and configured to overlap with the passage groove  11  within the wall  4   a  of the body  4 . Portion  12   a  having a larger cross-sectional area than portion  12   b . Portion  12   a  of passage  12  is preferably circular in shape and has a diameter of, for example, 1.8 mm for passing the Qmax. Portion  12   a  is situated in such a way that it can overlap only with said broad passage opening  11   a  of the groove  11  in the wall of the body  4 . Next, the smaller area of passage  12   b  is preferably substantially rectangular and has a width “W” with a dimension less than portion  12   a . In one embodiment, portion  12   b  has a length “E” of around 2 mm and a width “W” of around 1 mm. As shown in  FIG. 5 , only portion  12   b  is interposed with the convergent groove portion  11   b  in the wall  4   a  of the body  4 , causing during its rotation an intermediate flow Qgra that gradually decreases, in accordance with the angle rotated, to a relative final position P 3 , in which it supplies the Qmin. The length “E” of the passage area  12   b  of the conical member  5  is preferably sufficiently long for it to cover the maximum width of, for example, 1.1 mm of the stationary convergent groove  11   b  in the body  4 . 
     With reference to  FIGS. 4 and 5 , the passage opening  12  of the conical member  5  occupies a number of defined positions P 0 -P 3  in relation to the stationary regulating groove  11  of the wall  4   a  of the body  4 . In an initial position P 0 , the opening  12  is separated from the regulating groove  11  and corresponds with the “OFF” closure of the tap. In one embodiment, following the direction of rotation “R” of the conical member, and after 90° rotation corresponding to the position P 1 , both passage areas of portions  12   a  and  12   b  of the opening  12  overlap completely with the area  11   a  of considerable size opening  11   a  of groove  11  located within the wall  4   a  of the body, the maximum flow Qmax quickly being established in the outlet conduit  3   b . Continuing the rotation “R”, only the portion  12   b  of passage opening  12  overlaps with the convergent groove portion  11   b  as it successively crosses intermediate gas flow positions P 2 . Portion  12   b  of opening  12  and the convergent groove portion  11   b  are preferably shaped and dimensioned to provide an intermediate flow Qgra which is linearly regulated over the length of the gradually decreasing groove portion  11   b , and in accordance with the angular rotation of shaft  6 . In a final position P 3  of the passage opening  12 , the conical member  5  comes up against a limit that prevents its subsequent rotation in the direction “R”, and here in the final limit position P 3 , with the conical member  5  having completed a total angular path “St” equivalent to, for example, 270° from the “OFF” closure position P 0 , a constant minimum flow Qmin is provided to the outlet conduit  3   b . In the successive intermediate positions P 2  of linear regulating of the Qgra, and in the final position P 3 , only the narrow area  12   b  of the passage opening  12  of the conical member is interposed with the stationary convergent groove  11   b.