Patent Publication Number: US-6702159-B2

Title: Pouring spout for sparkling beverages

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a pouring spout for sparkling beverages, more specifically to an improvement of spout, which is used in a sparkling beverage server or dispenser capable of pouring a sparkling beverage typified by beer under operation of a lever and which can additionally pour, after pouring of a predetermined quantity of the beverage into a vessel such as a mug, fine froth over the beverage in the vessel. 
     2. Description of the Related Art 
     Some pouring spouts to be used in apparatuses for pouring sparkling beverages by operating levers, for example, in beer servers, have a function of additionally pouring, after pouring a predetermined quantity of beer into a mug by tilting a lever manually in one direction, fine beer froth over the beer in the mug. As a pouring spout having such a froth adding function, there is disclosed a spout having a frothing function in Japanese Unexamined Patent Publication No. 9-2590. The reason why such fine froth is additionally poured over the beer in a mug is that appropriately frothed beer gives improved texture when the beer goes through ones throat and that the froth prevents carbon dioxide gas from escaping quickly from the beer. Recently, froth to be poured additionally after pouring of beer is required to be as fine as cream. 
     In a beer server having such a frothing function, a lever attached to a beer pouring spout is switched over to pour beer only or to additionally pour froth from a single nozzle provided in the spout. Therefore, fine froth passes through the nozzle of the beer pouring spout after passage of beer through it, or vice versa. However, it is essential in pouring draft beer from a beer server that there is no residue of beer and froth thereof on the internal surface of the nozzle so as to achieve appropriate frothing of the draft beer poured through it. If beer is poured to another mug with the beer or froth remaining on the internal surface of the nozzle, frothing is likely to occur excessively to give foamy beer. A countermeasure is taken for it by defining an air inlet hole in the pouring nozzle to let the beer and froth remaining on the internal surface of the nozzle drip by their own weights. 
     As mentioned already, it is true that finely divided creamy foam is required as the additional froth, but creamy froth is highly viscous, so that it is difficult and also takes time to discharge the froth with the aid of air supplied through the air inlet hole. Therefore, it is necessary for an operator, after pouring beer into a mug and carrying out the froth adding operation, to operate the lever in a flash so as to pour liquid beer to flush froth remaining in the spout body and nozzle away from them. However, this operation of flushing the spout body and nozzle with beer inevitably requires a lot of skill, so that there has been awaited an advent of a beer pouring spout capable of pouring constantly fine froth of high quality requiring no such a skill. 
     Meanwhile, a spout for pouring sparkling beverages is disclosed in Japanese Patent Application No. 2000-19102 filed according to the proposition of the Applicant of the present invention. This spout has a nozzle for pouring a liquid into a mug and another nozzle for pouring froth into the mug, and also contains in its body various kinds of valve mechanisms for opening and closing a liquid channel and a froth channel defined so that a liquid and froth can be poured separately from the respective nozzles. 
     In the spout for pouring a sparkling beverage described above, the nozzle for pouring froth is long, so that a large amount of froth remains on the internal surface of the nozzle, which is causative of marring the flavor of the liquid. This problem cannot be solved merely by shortening the froth pouring nozzle. If a short froth pouring nozzle is merely used, a vigorous turbulent flow of froth is injected into a mug to be causative of excessive frothing and to be a hindrance in forming fine froth of high quality. 
     The present inventor has already proposed a countermeasure for the above problem and filed a Japanese Patent Application No. 2001-137771 relating to an invention entitled “Pouring spout for sparkling beverages.” In the pouring spout according to this invention, a slider is provided in the spout body such that it can slide within a liquid passage defined in its body in intimate contact with the passage under operation of a lever connected to the slider. Meanwhile, a valve seat provided on one end face of the slider is normally urged, by a resilient part attached to the other end face of the slider, to be pressed against the froth pouring valve element and closes the opening of an orifice defined in the froth pouring valve element to communicate with a through hole through which a sparkling beverage passes. When the slider is slid toward the resilient part against the resilience of, the valve seat retracts from the froth pouring valve element to open the opening of the orifice, through which the beverage flows out to impinge against the valve seat and undergoes frothing, and the thus obtained froth is designed to flow to the froth pouring nozzle through an annular groove formed on the internal surface of the spout body. 
     According to the constitution, the froth formed by impingement of a sparkling beverage against the valve seat is allowed to flow through the annular groove defined in the spout body into the froth pouring nozzle, and thus the impetus of the froth flowing into the nozzle can be attenuated to prevent favorably excessive frothing occurring when a short froth pouring nozzle is used. 
     However, in the sparkling beverage pouring spout described above, when a liquid or froth thereof is poured, the liquid or froth is brought into contact with the internal surface of the liquid passage defined in the spout body and partly with the slider and remain there. Since the slider repeats sliding in intimate contact with the internal surface of the liquid passage of the spout body under tilting operation of the lever in each time the liquid or froth is poured, the liquid is applied to the internal surface of the liquid passage in the spout body over the full length of the passage and remains there. Thus, the external surface of the slider sliding in intimate contact with the internal surface of the liquid passage defined in the spout body is caused to assume airtightness due to the liquid applied to the passage and remains there. 
     Meanwhile, if the slider is moved away in a direction such that the valve seat retracts from the froth pouring valve element when froth is to be poured through the sparkling beverage pouring spout, the resilient part retained between the slider and the stopper is pressed against the stopper and is compressed, and the volume of the space in which the stopper and the slider are housed reduces. In this case, due to the high airtightness between the slider and the internal surface of the spout body brought about by the liquid remaining there as described above, the air having been present in that housing space is already ejected along the external surface of the stopper having a lower resistance to airtightness to the outside of the pouring spout. The beer liquid contains a foaming component, so that when the air is ejected along the external surface of the stopper, foaming occurs inevitably accompanied by ejection of the beer liquid. In other words, the ejected beer liquid seeps to the outside of the spout body to deposit thereon, causing contamination of the spout body, disadvantageously. 
     On the other hand, it is contemplable, as techniques of preventing foaming, in a beer spout structure as disclosed in Japanese Unexamined Patent Publication No. 2000-318799, to notch partly a cover corresponding to the stopper and facilitate incoming and outgoing of air, or to define a through hole in the spout body communicating to the outside. However, these structures are all accompanied by leakage of beer liquid from the spout body to the outside, and wetting of the external surface of the spout body with the seeped beer liquid occurs unavoidably, causing contamination of the external surface. 
     Meanwhile, Japanese Unexamined Patent Publication No. 2000-318799 discloses a valve mechanism, in which a froth switching valve is contained in a cavity of a first movable rod, and a pressurized beer liquid is allowed to flow into a sliding clearance between the cavity of the first movable rod and a second movable rod by tilting an operation lever clockwise to open the valve. The beer liquid is then injected through orifices defined in an annular U-shaped groove formed on the first movable rod to the external surface of the first movable rod to effect frothing of the beer liquid, and the resulting froth is poured from a froth pouring port through the U-shaped groove. During pouring of froth, the annular U-shaped groove having the orifices for injecting the beer liquid is positioned in alignment with the froth pouring port, and the froth formed through ejection of the beer liquid through the orifices partly forms turbulence and flows down vigorously to the froth pouring port. Therefore, the length of the froth pouring nozzle is increased. 
     Since the sparkling beverage pouring spout has a long froth pouring nozzle, it involves a problem that a large quantity of froth remains on the internal surface of the nozzle to cause marring of the taste of the beverage. This problem cannot be solved merely by using a short pouring nozzle, but the short froth pouring nozzle injects a vigorous turbulence of froth into a mug, causing excessive frothing or being a factor preventing formation of fine froth of high quality. 
     Further, the conventional pouring spouts for sparkling beverages involve problems that if the froth remained around the resilient part such as a coiled spring is not discharged but is exposed to the outside air for a long time, it undergoes deterioration, so that the pouring spout must be disassembled and cleaned frequently, taking much trouble, and that the pouring spouts have structures difficult to disassemble. 
     SUMMARY OF THE INVENTION 
     The present invention was accomplished with a view to solving suitably the problems inherent in the pouring spouts for sparkling beverages of the prior art as described above and is directed to providing a pouring spout for sparkling beverages enabling unskilled operators to carry out appropriate addition of fine and highly viscous froth without requiring the sophisticated skill of cleaning the nozzles and the like with a sparkling beverage nor causing excessive frothing. 
     Further, the present invention was accomplished with a view to solving suitably the problems inherent in the pouring spouts for sparkling beverages described above and is directed to providing a clean and hygienic pouring spout for sparkling beverages capable of preventing wetting of the spout body with the seeped beverage. 
     Further, the present invention was accomplished with a view to solving suitably the problems inherent in the pouring spouts for sparkling beverages described above and is directed to providing a pouring spout for sparkling beverages which controls turbulence in pouring froth to prevent excessive frothing and which facilitates disassembling and cleaning. 
     In order to solve the problems described above and to attain the intended objectives, the pouring spout for a sparkling beverage according to one aspect of the present invention has a constitution in which the sparkling beverage is poured into a vessel by a first operation of a lever, and froth of the sparkling beverage is poured additionally into the vessel by a second operation of the lever; and is characterized in that the pouring spout has a sparkling beverage pouring nozzle and a froth pouring nozzle branching out from a sparkling beverage supply channel defined in a spout body; a slider inserted to the sparkling beverage supply channel to be slidable therein and is connected to the lever to be driven thereby to advance and retract; a sleeve inserted slidably into the sparkling beverage supply channel and is connected at one end to the slider; the sleeve having through holes defined in the peripheral wall to be able to communicate with the froth pouring nozzle at the time of froth pouring operation; a first valve element to be seated on a first valve seat provided at an inlet of the sparkling beverage supply channel under an action of a first resilient part; a valve rod connected at one end to the first valve element and is inserted at the other end to the sleeve; the valve rod having a liquid passage defined axially therein to penetrate the first valve element; and a second valve element inserted to the sleeve and is connected at one end to the valve rod, the second valve element having an orifice defined at the other end to communicate with the liquid passage, that end having the orifice being seated on a second valve seat provided in the slider under an action of a second resilient part; wherein, before operation of the lever, the first valve element is seated on the first valve seat to interrupt flowing of the sparkling beverage into the sparkling beverage supply channel, whereas the second valve is seated on the second valve seat to close the orifice; the first operation of the lever retracts the valve rod in the axial direction against the first resilient part through the second valve element being seated on the second valve seat to let the first valve element leave the first valve seat open and to pour the sparkling beverage out of the sparkling beverage pouring nozzle through the sparkling beverage supply channel; the second operation of the lever causes the slider to advance in the axial direction against the second resilient part to be spaced away from the valve rod forcing the first valve element to seat on the first valve seat, and also causes the second valve element to leave the second valve seat open and effect frothing of the sparkling beverage from the liquid passage when it flows through the orifice to pour the resulting froth from the froth pouring nozzle through the through holes defined in the sleeve. 
     Here, the sleeve has on the external surface a first annular groove and a second annular groove defined at a necessary interval therebetween, whereas the spout body has a first air vent and a second air vent to allow the sparkling beverage supply channel to communicate with the outside; the sparkling beverage pouring nozzle and the froth pouring nozzle are designed to communicate with the first air vent and the second air vent through the first annular groove and the second annular groove, respectively, only at a fixed position of the sleeve before operation of the lever. 
     The first operation of the lever interrupts communication between the first annular groove and the first air vent to stop introduction of the outside air into the sparkling beverage pouring nozzle, while communication between the second annular groove and the second air vent is maintained to introduce outside air still into the froth pouring nozzle. Meanwhile, the second operation of the lever interrupts communication between the second annular groove and the second air vent to stop introduction of the outside air into the froth pouring nozzle, while communication between the first annular groove and the first air vent is maintained to introduce outside air still into the sparkling beverage pouring nozzle. 
     In order to solve the problems described above and to attain the intended objectives, the pouring spout for a sparkling beverage according to another aspect of the present is provided with a slider sliding within a liquid passage defined in a spout body in intimate contact therewith; a lever connected to the slider and is tilted to slide the slider within the liquid passage; a resilient part disposed on one end face of the slider so as to press a valve seat provided on the other end face of the slider against a pouring valve element disposed to oppose the latter end face; a through hole for the sparkling beverage defined in the inside of the pouring valve element and opens to that end face against which the valve seat for the pouring valve element is pressed; a pouring nozzle providing a channel of the sparkling beverage flowed out from an opening of the through hole opened by retraction of the valve seat from the pouring valve element when the slider is slid toward the other end face against the resilience of the resilient part; and a communicating passage for securing communication between a housing space defined in the spout body, in which the resilient part is housed and the pouring nozzle. 
     In order to solve the problems described above and to attain the intended objectives, the pouring spout for a sparkling beverage according to another aspect of the present invention is provided with a slider sliding within a liquid passage defined in a spout body in intimate contact therewith; a lever connected to the slider and is to be tilted to slide the slider within the liquid passage; a resilient part disposed on one end face of the slider so as to press a valve seat provided on the other end face of the slider against a froth pouring valve element disposed to oppose the latter end face; an orifice defined as a passage for the sparkling beverage introduced into the froth pouring valve element and opening to the froth pouring valve element; an annular groove defined on the internal surface of the spout body such that it provides a channel for froth formed when the sparkling beverage flowed out through the opening opened by retraction of the valve seat from the froth pouring valve element by sliding the slider toward that former end face against the resilience of the resilient part impinge against the valve seat; and a froth pouring nozzle communicating with the annular groove. 
     Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings illustrated by way of examples the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention together with the objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which: 
     FIG. 1 is an exploded cross-sectional view showing components constituting the pouring spout for sparkling beverages according to a preferred embodiment of the invention; 
     FIG. 2 is a cross-sectional view of the pouring spout for sparkling beverages according to the embodiment connected to a beverage supply pipe of a beverage server, showing a state where the lever is not operated yet but is located at the neutral position, and the spout is pouring neither a sparkling beverage nor froth thereof; 
     FIG. 3 is an enlarged view of a pertinent portion of the pouring spout for sparkling beverages showing the positional relationship of the sleeve in FIG. 2; 
     FIG. 4 is a cross-sectional view of the pouring spout for sparkling beverages according to the embodiment connected to the beverage supply pipe of a beverage server, showing a state where only a sparkling beverage is poured by a first operation of the lever; 
     FIG. 5 is an enlarged view of a pertinent portion showing the positional relationship of the sleeve in FIG. 4; 
     FIG. 6 is a cross-sectional view of the pouring spout for sparkling beverages according to the embodiment connected to the beverage supply pipe of a beverage server, showing a state where only fine froth is poured by a second operation of the lever; 
     FIG. 7 is an enlarged view of a pertinent portion showing the positional relationship of the sleeve in FIG. 6; 
     FIG. 8 is a side view of a sparkling beverage server provided with the pouring spout for sparkling beverages according to the preferred embodiment; 
     FIG. 9 is a cross-sectional view of the pouring spout for sparkling beverages according to another embodiment of the invention, in which the lever is located at the neutral position; 
     FIG. 10 is an enlarged view of a pertinent portion in FIG. 9; 
     FIG. 11 is an exploded cross-sectional view showing components of the pouring spout for sparkling beverages, with the valve rod assembly being disassembled; 
     FIG. 12 is a cross-sectional view of the pouring spout for sparkling beverages, showing a state where the lever shown in FIG. 9 is tilted to shift to a liquid pouring position; 
     FIG. 13 is an enlarged view of a pertinent portion in FIG. 12; 
     FIG. 14 is a cross-sectional view of the pouring spout for sparkling beverages, showing a state where the lever shown in FIG. 9 is tilted to be shifted to a froth pouring position; and 
     FIG. 15 is an enlarged view of a pertinent portion in FIG.  14 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The pouring spout for sparkling beverages according to the present invention will be described below by way of preferred embodiments referring to the attached drawings. In the following embodiments, the pouring spout for sparkling beverages are explained by giving beer pouring spouts, for example, to be attached to beer servers. 
     FIG. 1 is an exploded cross-sectional view showing a beer pouring spout  44  according to a preferred embodiment of the invention. The beer pouring spout  44  is attached to a beer server  46  shown in FIG.  8 . Meanwhile, FIG. 2 is a cross-sectional view of the beer pouring spout  44  connected to a beer supply pipe extended horizontally from the beer server  46 , showing a state where the spout is pouring neither a sparkling beverage nor froth thereof. The beer pouring spout  44  consists essentially of a spout body  10 , various kinds of valve mechanisms (to be described later) housed in the spout body  10  to carry out operations of opening and closing beer channel and froth channel respectively, and a lever  18  to be tilted to carry out switching between a beer pouring position and a froth pouring position, as shown in FIG.  1 . 
     The spout body  10  shown in FIG. 1 contains a beer supply channel  12  having a necessary diameter running horizontally through the body  10  and a pair of pouring nozzles branching out diagonally downward therefrom parallel to each other, i.e., one is a beer pouring nozzle  14  and the other is a froth pouring nozzle  16 . These two nozzles  14  and  16  communicate with each other within the beer supply passage  12 . In FIG. 1, the right nozzle extended from the spout body  10  diagonally downward is the beer pouring nozzle  14  and the left nozzle is the froth pouring nozzle  16 . 
     In FIG. 1, the diameter of the spout body  10  is enlarged at the right end to form a large diameter portion containing a hemispherical cavity  26  to which the beer supply channel  12  opens. This hemispherical cavity  26  functions as a first valve seat to be explained later. The spout body  10  is fitted to a beer supply pipe  48  by engaging a male screw  10   a  formed on the external surface of the large diameter portion with a female screw  50   a  of a union nut  50  shown in FIG.  2 . The spout body  10  has on the left side a rising portion  52  formed integrally therewith. The rising portion  52  contains a vertical hole  52   a  communicating with the beer supply passage  12 , and a ball  54  and a connecting rod  56  provided at the lower end of the pouring operation lever  18  are designed to be inserted to the vertical hole  52   a . The connecting rod  56  is inserted to an inserting hole  20   a  of a slider  20  (to be described later) and transmits the movement of the lever  18  thereto. Here, the lever  18  is incorporated into the spout body  10  by engaging a male screw  52   b  formed on the external surface of the rising portion  52  with a female screw  58   a  of a union nut  58  attached to the ball  54  of the lever  18 . 
     Further, the spout body  10  has a first air vent  60  and a second air vent  62  securing communication of the beer supply channel  12  with the outside. These two air vents  60  and  62  function to achieve connection and disconnection of the beer pouring nozzle  14  and the froth pouring nozzle  16  to and from the outside, in cooperation with a first annular groove  64  and a second annular groove  66  defined on the external surface of a sleeve  24  (to be described later) at a necessary interval. In FIG. 1, the first air vent  60  locates on the right side, one end of which opens to the upper surface of the spout body  10 , and the other end opens to the beer pouring nozzle  14 . Meanwhile, the second air vent  62  locates on the left side of the first air vent  60  in FIG. 1 with a predetermined interval being secured between them, and opens to the upper surface of the spout body  10 . The distance between the first air vent  60  and the second air vent  62  opening to the beer supply pipe  12  is designed to correspond to the distance between the first annular groove  64  and the second annular groove  66  (to be described later). 
     The beer supply channel  12  in the spout body  10  contains various kinds of valve mechanisms for opening and closing the beer channel and froth channel respectively. The valve mechanisms consist essentially of the slider  20 , the sleeve  24 , a valve rod  34 , a first valve element  30 , a first valve seat  26 , a first resilient part  28 , a second valve element  42 , a second valve seat  38 , a second resilient part  40 , etc. 
     In FIG. 1, the reference number  20  denotes a cylindrical slider inserted slidably to the beer supply channel  12  substantially in intimate contact therewith, and the slider  20  has the inserting hole  20   a  defined substantially at the middle orthogonal to the axis thereof. When the pouring spout  44  is to be assembled, the connecting rod  56  provided at the lower end of the lever  18  is inserted to this inserting hole  20   a , and the slider  20  is advanced and retracted by tilting the lever  18  forward and backward. While the slider  20  has a cylindrical recess defined on the right end thereof in FIG. 1, in which a sealing body  38  is fitted. The sealing body  38  functions as the second valve seat permitting seating of the second valve element  42  thereon. Here, the slider  20  has a male screw  20   b  formed on the external surface at the right end portion thereof, which is engaged with a female screw  25   a  formed on the internal surface of the sleeve  24  (to be described later) on the left end portion to achieve connection between the slider  20  and the sleeve  24 . 
     In FIG. 1, the reference number  24  denotes a cylindrical sleeve to be inserted into the beer supply channel  12  to be slidable therein and substantially in intimate contact therewith. The sleeve  24  contains a cylindrical cavity  25  running axially through it. The female screw  25   a  formed on the internal surface of the cylindrical cavity  25  on the left side is engaged with the male screw  20   b  of the slider  20 . Meanwhile, the right end portion of the cylindrical cavity  25  is provided with an inside step  25   b  which functions as a positioning face for the second resilient part  40  (to be described later) inserted to the cylindrical cavity  25 . Further, the inside step  25   b  has a valve rod inserting hole  68  communicating with the cylindrical cavity  25  to admit insertion of the valve rod  34  (to be described later) thereto. 
     The first annular groove  64  and the second annular groove  66  are formed on the external surface of the sleeve  24  at a predetermined interval to achieve connection and disconnection to and from the beer pouring nozzle  14  and the froth pouring nozzle  16  in cooperation with the first air vent  60  and the second air vent  62  defined in the spout body  10 , respectively. In FIG. 1, the first annular groove  64  and the second annular groove  66  of the sleeve  24  are located on the right side and on the left side respectively. The distance between the first annular groove  64  and the second annular groove  66  is adapted to correspond to the distance between the first air vent  60  and the second air vent  62 , as explained already. Further, four through holes  22  are defined radially in the sleeve  24  to communicate with the cylindrical cavity  25  with the right edge portion of each through hole  22  overlapping with the second annular groove  66 . These through holes  22  can be allowed to communicate with the froth pouring nozzle  16  by shifting the lever  18  (to be described later) to the froth pouring position. 
     As mentioned already, the large diameter portion of the spout body  10  has a hemispherical recess serving as the first valve seat  26 , which communicates with the inlet of the beer supply channel  12 . Further, the first valve element  30  is designed to be seated on the first valve seat  26  to achieve freely connection and disconnection between the beer supply pipe  48  and the beer supply channel  12 . The first valve element  30  is urged resiliently by the first resilient part  28  such as a coiled spring interposed between itself and the conical internal face  48   a  of the beer supply pipe  48  to be normally abutted against the first valve seat  26 . Further, in FIG. 1, the left half of the first valve element  30  is designed to form a hemispherical rubber sealing face  30   a  to ensure liquid tightness between itself and the first valve seat  26 ; whereas the right half of the first valve element  30  is designed to form a spindle-shaped head  30   b . The first valve element  30  also has a through hole  31  defined in alignment with the center axis thereof to communicate with a liquid passage  32  (to be described later) of the valve rod  34 . 
     The valve rod represented by the reference number  34  in FIG. 1 is a long rod material having a liquid passage  32  defined through it in alignment with the center axis thereof. The valve rod  34  is connected at the right end to the first valve element  30  in FIG. 1 to allow the liquid passage  32  to communicate with the through hole  31  of the first valve element  30 . The valve rod  34  also has a male screw  34   a  formed on the external surface at the left end portion. The valve rod  34  and the second valve element  42  are designed to be connected to each other by engaging the male screw  34  of the former with a female screw  42   a  formed on the internal surface of the latter. Here, the valve rod  34  is inserted to the sleeve  24  through the valve rod inserting hole  68  thereof. Further, the second resilient part  40  (to be described later) such as a coiled spring is fitted on the valve rod  34  and is interposed resiliently between the second valve element  42  (to be described later) connected to the valve rod  34  and the inside step  25   b  of the sleeve  24  to forcibly seat the second valve element  42  on the second valve seat  38  of the slider  20 . 
     In FIG. 1, the reference number  42  denotes the second valve element to be inserted into the sleeve  24 . The second valve element  42  has a cylindrical shape having a short axis, which can be housed in the sleeve  24  substantially in intimate contact therewith, and has a female screw  42   a  axially formed at the right end portion in FIG.  1 . The second valve element  42  is connected to the valve rod  34  by engaging the female screw  42   a  of the former to the male screw  34   a  formed on the latter at the left end portion, as mentioned already. The second valve element  42  has a narrow hole  36  defined in alignment with the center axis thereof. By connecting the second valve element  42  and the valve rod  34  to each other in assembling the pouring spout, the narrow hole  36  communicates with the liquid passage  32  defined in the valve rod  34 . The narrow hole  36  is defined so as to convert the beer coming through the liquid passage  32  into fine froth when the beer passes through it, so that the hole  36  is designed to have an inside diameter that is as very small as that of an orifice. Further, a head having a reduced diameter is formed at the left open end portion of the second valve element  42 , as shown in FIG. 1, so that it can be seated on the second valve seat  38  defined in the slider  20 . Here, the force of bringing the second valve element  42  into press contact with the second valve seat  38  to normally allow the former to be seated on the latter is mainly applied by the first resilient part  28  provided on the first valve element ( 30 ) side. 
     After the respective parts described above are organically assembled, the resulting assembly is inserted to the beer supply channel  12  of the spout body  10 . In an actual assembly, the end of the valve rod  34  where the first valve element  30  is not present is inserted to the sleeve  24  through the valve rod inserting hole  68 . The valve rod  34  inserted to the sleeve is further inserted to the second resilient part  40  typified by a coiled spring, and then the male screw  34   a  provided at the left end portion of the valve rod  34  is engaged with the female screw  42   a  of the second valve element  42 . Here, the coiled spring  40  can be housed in the cylindrical cavity  25  of the sleeve  24 , and the right end portion and the left end portion of the coiled spring  40  are controlled by the inside step  25   b  and by the second valve element  42 , respectively, as shown in FIG.  2 . 
     Next, the sleeve  24  and the slider  20  are connected to each other by engaging the female screw  25   a  formed on the internal surface of the sleeve  24  at the left end portion with the male screw  20   b  formed on the external surface of the slider  20  at the right end portion. Here, the coiled spring  40  contained in the cylindrical cavity  25  of the sleeve  24  is compressed to resiliently urge the sleeve  24  axially rightward in FIG.  2  and also to seat the second valve element  42  on the second valve seat  38 . Incidentally, the coiled spring  40  is designed to have a degree of resilience such that it can urge the slider  20  leftward to retain the lever  18  at the upright position as shown in FIG. 2, provided that the resilience of the coiled spring as the second resilient part  40  is designed to be smaller than that of the coiled spring  28  as the first resilient part. 
     After the assembly of the various kinds of valve mechanisms is inserted to the beer supply channel  12  of the spout body  10 , the lever  18  is fitted to the spout body  10 . Further, the spout body  10  is fitted to the beer supply pipe  48 . These fitting procedures are of public knowledge, descriptions of them will be omitted. Incidentally, since the coiled spring  28  is resiliently interposed between the first valve element  30  and the conical internal face  48   a  of the beer supply pipe  48  and is present as such after completion of assembly, the first valve element  30  is seated on the first valve seat  26  to normally interrupt communication between the beer supply pipe  48  and the beer supply channel  12 . 
     FIG. 2 is a cross-sectional view of the beer pouring spout  44  of the embodiment having the valve mechanism assembly shown in FIG. 1 incorporated into the spout body  10 . In FIG. 2, the lever  18  is not operated but is located at the neutral position, and the spout  44  is pouring neither beer nor froth thereof. More specifically, before the lever  18  is operated, the coiled spring  28  disposed in abutment with the conical internal face  48   a  of the beer supply pipe  48  resiliently urges the first valve element  30  to seat the valve element  30  on the first valve seat  26  and cuts off supply of beer from the beer supply pipe  48  to the beer supply channel  12 . Further, since the second valve element  42  connected to the valve rod  34  is urged by the coiled spring  28  axially leftward, the second valve element  42  is seated on the first valve seat  26  provided in the slider  20  to close the narrow hole  36  of the second valve element  42 . Thus, neither beer nor froth thereof is supplied to the beer pouring nozzle  14  or to the froth pouring nozzle  16 . 
     Further, as shown in FIG. 3, when the lever  18  is at the neutral position, the first annular groove  64  and the second annular groove  66  are defined on the external surface of the sleeve  24  are adapted to oppose the first air vent  60  and the second air vent  62  defined in the spout body  10 , respectively. Therefore, the outside air is introduced in the following two routes: (1) first air vent  60 →first annular groove  64 →beer pouring nozzle  14 ; and (2) second air vent  62 →second annular groove  66 →froth pouring nozzle  16 . In other words, the beer remaining on the internal surface of the beer pouring nozzle  14  after the immediately preceding beer pouring operation can be caused to drop easily by introduction of air, whereas the portion of froth remaining on the internal surface of the froth pouring nozzle  16  after the immediately preceding froth pouring operation can be also caused to drop easily by introduction of air. 
     As shown in FIG. 4, when the lever  18  is tilted endways (this operation is referred to as a first operation), the slider  20  retracts rightward within the beer supply channel  12 . Since the slider  20  is connected to the sleeve  24 , and since the valve rod  34  connected end-to-end to the second valve element  42  is urged leftward by the second coiled spring  40 , the valve rod  34  slides rightward together with the slider  20 . This makes the first valve element  30  to slide rightward against the resilience of the coiled spring  28  to leave the first valve seat  26  open. Thus, the beer supplied through the beer supply pipe  48  is poured and the beer pouring nozzle  14  through the beer supply channel  12  into a mug  70  shown in FIG.  8 . 
     Here, the second valve element  42  is urged axially leftward by the coiled spring  40  as shown in the enlarged view of a pertinent portion of FIG. 5, so that it is seated on the second valve seat  38  to close the narrow hole  36 . Therefore, no froth is supplied to the froth pouring nozzle  16  at this stage. Further, since the slider  20  has moved rightward by the first operation of the lever  18 , the communication between the first annular groove  64  of the sleeve  24  and the first air vent  60  of the spout body  10  is interrupted. Thus, there occurs no introduction of the outside air into the beer pouring nozzle  14  to prevent effectively excessive frothing which can be caused by migration of air in pouring beer. Here, the slider  20  at the stage of the first operation is not in such a position as can interrupt the communication between the second annular groove  66  of the sleeve  24  and the second air vent  62  of the spout body  10 . That is, since the outside air is introduced into the froth pouring nozzle  16 , the froth remaining in the nozzle  16  is still caused to drop. 
     As shown in FIG. 6, when the lever  18  is tilted backward (this operation is referred to as a second operation), the slider  20  advances leftward within the beer supply channel  12  against the resilience of the second coiled spring  40 . Here, the valve rod  34  is resiliently urged leftward by the first coiled spring  28  through the first valve element  30 , the valve rod  34  locates at the same position as in FIG. 2, where the lever  18  is at the neutral position. More specifically, the second valve seat  38  defined in the slider  20  is spaced away from the second valve element  42  fixed to the valve rod  34  to open the narrow hole  36  defined in the second valve element  42 . Thus, the beer from the beer supply pipe  48  will flow out from the narrow hole  36  through the through hole  31  penetrating the first valve element  30  and the liquid passage  32  of the valve rod  34 . However, since the narrow hole  36  has an inside diameter as very small as that of an orifice as explained before, the beer is converted into fine froth. Next, as shown in FIG. 7, the froth flows through the radial through holes  22  defined in the sleeve  24  into the froth pouring nozzle  16  and is poured additionally over the beer contained in the mug  70 . 
     As the enlarged view of a pertinent portion of FIG. 7 shows, the slider  20  is already moved leftward by the second operation of the lever  18 , so that the communication between the second annular groove  66  of the sleeve  24  and the second air vent  62  of the spout body  10  is interrupted. Thus, there occurs no introduction of the outside air into the froth pouring nozzle  16 , making it possible to form fine froth of high quality without migration of the outside air thereto. Incidentally, the slider  20  at the stage of the second operation is not in such a position as can interrupt the communication between the first annular groove  64  and the first air vent  60 . That is, since the outside air is introduced to the beer pouring nozzle  14 , the beer remaining in the nozzle  14  is still caused to drop by the air thus introduced. 
     FIG. 9 is a cross-sectional view of the pouring spout for sparkling beverages according to another embodiment of the invention; FIG. 10 is an enlarged view of a pertinent portion in FIG. 9; and FIG. 11 is an exploded view. The sparkling beverage pouring spout  130 , which is used, for example, for pouring beer into a mug, is composed essentially of a spout body  131 , a lever  132  to be incorporated into the spout body  131  and to be tiltably operated manually, and a valve rod assembly  133  to be housed in the spout body  131 . The pouring spout  130  is adapted to be fastened to the downstream end portion of a beer supply pipe  134  of a beer dispenser (not shown) with a female screw  135 . 
     The spout body  131  has a cylindrical shape having a liquid passage  138  formed to penetrate through it in alignment with the center axis thereof. The spout body  131  also has a vertical hole  139  defined on the upper left side (opposite to the junction with the beer supply pipe  134 ), and an annular protrusion  140  formed along the outer opening of the vertical hole  139 . At that end portion of the spout body  131  to be engaged with the female screw  135 , the liquid passage  138  is expanded to form an expanded portion  141 . The portion connecting the expanded portion  141  and the liquid passage  138  to each other is formed into a smooth hemispherical valve seat  137 . Further, a male screw  142  to be engaged with the female screw  135  is formed on the external surface of the expanded portion  141 . 
     The spout body  131  has a pair of nozzles formed on the lower side, i.e., a liquid pouring nozzle  143  formed as a longer cylindrical body closer to the expanded portion  141  and a froth pouring nozzle  144  formed as a shorter cylindrical body closer to the vertical hole  139  in which a lever  132  is to be fitted. While the froth pouring nozzle (pouring nozzle)  144  has a passage  145  communicating with the liquid passage  138 , an annular groove  146  is defined on the internal surface of the spout body  131  circumferentially along the liquid passage  138  to overlap partly with the opening of the passage  145 . Further, the liquid pouring nozzle  143  has a passage  148 , and a pair of air vents  149   a  and  149   b  are defined on the upper side of the spout body  131  to communicate with the liquid passage  148 . 
     The lever  132  has at the distal end a ball  150  to be pivoted freely in the annular protrusion  140 , and a connecting rod  151  is provided to protrude from the distal end of the ball  150 . The connecting rod  151  is notched or forked at the distal end. Further, a cover  152  is applied around the ball  150 . The cover  152  is fitted liquid tight to the annular protrusion  140  to prevent leakage of the sparkling liquor. 
     The valve rod assembly  133  to be housed slidably in the liquid passage  138  of the spout body  131  consists essentially of a slider  155  capable of sliding in intimate contact with the internal surface of the liquid passage  138 , a stopper  156  which slides along the liquid passage  138  to close the distal end opening (opposite to the opening of the expanded portion  141 ) of the liquid passage  138 , a coiled spring serving as a resilient part  157  to be interposed between the slider  155  and the stopper  156 , and a valve member  160 . 
     The slider  155  has a center through hole  161  penetrating the center axis thereof and also an opening communicating with the center through hole  161  and opening  162  radially outward. The connecting rod  151  of the lever  132  is inserted to this opening  162  so that the slider  155  can slide leftward and rightward by tilting the lever  132  endways and backward. The slider  155  has a recess formed on the right end face thereof (facing the expanded portion  141 ), in which an annular sealing piece  163  having a conical internal face serving as a valve seat is fitted, and also a bearing seat  164  for the resilient part  157  formed on the left end face of the slider  155 . 
     The stopper  156  has a bearing seat  165  for the resilient part  157  and also a bottomed hole  166  formed from the right end face in alignment with the center axis. The bottomed hole  166  has a female screw formed on the internal surface. 
     The valve member  160  is rod-shaped and is expanded at the proximal end portion to form a head serving as a first valve element (liquid pouring valve element)  170 . The valve element  170  has an annular sealing piece  171  fitted to the neck thereof. The liquid passage  138  is designed to close when the annular sealing piece  171  is seated on the internal surface (valve seat  137 ) of the expanded portion  141  of the spout body  131 . Further, the valve member  160  has a large diameter portion  172  at the middle thereof. The large diameter portion  172  has a second valve element (pouring valve element)  173  formed on that end face which is distal from the head. The second valve element  173  is adapted to be seated on the annular sealing piece  163  provided on the slider  155 . 
     The valve member  160  has a bottomed through hole  174  defined from the end face of the head (first valve element)  170  thereof to the middle of the large diameter portion  172  in alignment with the center axis thereof. A narrow hole  175  through which a sparkling beverage flows is defined from the bottom of the bottomed through hole  174  in the large diameter portion  172  to the end face of the second valve element  173  to be abutted against the annular sealing piece  163 . The narrow hole  175  has an opening  175   a  opening to the abutting face of the second valve element  173  toward the lever  132  rather than the froth pouring nozzle  144 . Further, a rod  176  protrudes from the large diameter portion  172  in alignment with the center axis to be away from the head. The rod  176  has a male screw  177  formed at the distal end portion and is inserted to the center through hole  161  of the slider  155 , and the male screw  177  formed at the distal end is engaged with the female screw of the bottomed hole  166  of the stopper  156 , so that the stopper  156  and the valve member  160  move together. Incidentally, the large diameter portion  172  has a U-shaped groove  178  defined on the external surface thereof. 
     The valve rod assembly  133  of the sparkling beverage pouring spout  130  having the constitution as described above is obtained by putting four elements together, i.e. by inserting the rod  176  to the center through hole  161  of the slider  155  and to the resilient part  157  and bringing the distal end portion of the rod  176  into screw engagement with the bottomed hole  166 . Then, the valve rod assembly  133  is inserted to the liquid passage  138  of the spout body  131 , and after the connecting rod  151  of the lever  132  is inserted to the vertical hole  139  as if the forked end portion of the connecting rod  151  ride astride the rod  176  within the opening  162  of the slider  155 , the cover  152  is screwed liquid tight onto the annular protrusion  140 . 
     Finally, the male screw  142  formed on the external surface of the expanded portion  141  is inserted to the female screw  135  and is engaged therewith, and thus the sparkling beverage pouring spout  130  is connected to a beverage dispenser (see FIG.  9 ). In the state where the valve rod assembly  133  is incorporated into the spout body  131 , the resilient part  157  is adapted to be housed in the housing space S defined by the internal surface of the spout body  131 , the stopper  156  and the slider  155 , as shown in FIG.  10 . Further, a communicating passage  179  is formed through the portion of the spout body  131  defining housing space S at a lower position to communicate with the passage  145  of the froth pouring nozzle  144 . It should be noted here that, while the valve rod assembly  133  slides rightward and leftward within the liquid passage  138  to pour beer and froth respectively, the communicating passage  179  is designed to be located at a position where the housing space S communicates constantly with the froth pouring nozzle  144  regardless of the position of the valve rod assembly  133 . 
     When the sparkling beverage pouring spout  130  is to be cleaned, it is disassembled into the state shown in FIG.  11 . More specifically, the pouring spout  130  is disassembled into three components, i.e., the lever  132 , the spout body  131  and the valve rod assembly  133 , enabling easy cleaning of the spout  130  without disassembling the valve rod assembly  133  into individual parts ( 155 ,  156 ,  157  and  160 ). 
     As can be understood clearly from FIGS. 9 and 10, in the sparkling beverage pouring spout  130  of this embodiment, the resilient part  157  having much clearances admitting entrance of froth is housed in the housing space S defined in the spout body  131  on the left end side of the froth pouring nozzle  144 , and neither froth nor a liquid to be poured into a mug is designed to flow into the space where the resilient part  157  is located. 
     In the state shown in FIGS. 9 and 10, where the lever  132  is at the neutral position, the opening  175   a  of the narrow hole  175  opening to the abutting face of the second valve element  173  is closed by the annular sealing piece  163  of the slider  155  under resilience of the resilient part  157 . The sealing piece  171  attached to the head (first valve element  170 ) of the valve member  160  is subjected to the liquid pressure of the beer supplied from the beer supply pipe  134  to be pressed against the valve seat  137 , so that the communication between the beer supply pipe  134  and the liquid passage  138  is interrupted. 
     Dimensions or positions of the elements in the pertinent portion of the pouring spout  130  will be described. The opening  175   a  of the narrow hole  175  on the valve element ( 173 ) side or the sealing piece  163  is adapted to overlap with the location of the annular groove  146  defined in the spout body  131 . Further, the air vents  149   a  and  149   b  are positioned to oppose the annular groove  178  defined on the external surface of the large diameter portion  172  of the valve member  160 . When the valve member  160  is moved leftward from the neutral position, the communication of the air vents  149   a  and  149   b  with the annular groove  178  is designed to be interrupted (see FIG.  12 ). Further, the annular groove  146  and the passage  145  of the froth pouring nozzle  144  are staggered from each other by the length from the point of contact between the elongation of the substantially conical open face of the sealing piece  163  expanding toward the large diameter portion  172  and the internal surface of the annular groove  146  to the internal surface of the through hole  145 . 
     Next, operations of the sparkling beverage pouring spout according to the second embodiment will be described. 
     As mentioned already, when the lever  132  is at the neutral position (as shown in FIG.  9 ), neither beer nor froth is poured. More specifically, before the lever  132  is operated, the liquid pressure of beer resiliently urges the sealing piece  171  in the first valve element  170  to be seated on the valve seat  137  to interrupt supply of beer from the beer supply channel  134  to the liquid passage  138  defined in the spout body  131 . Meanwhile, since the slider  155  is urged by the resilient part  157  toward the valve member  160 , the sealing piece  163  provided on the right end face of the slider  155  is pressed against the second valve element  173  to close the opening  175   a  of the narrow hole  175 . Thus, both supply of beer to the liquid pouring nozzle  143  and supply of froth to the froth pouring nozzle  144  are interrupted. 
     When the lever  132  is at the neutral position, the annular groove  178  formed on the external surface of the large diameter portion  172  of the valve member  160  is adapted to oppose the air vents  149   a  and  149   b  defined in the spout body  131 , so that the outside air is introduced into the liquid pouring nozzle  143 . Thus, the beer remaining on the internal surface of the liquid pouring nozzle  143  after the previous beer pouring operation is caused to drop and discharged easily by the introduction of air. 
     When beer is poured into a mug, the lever  132  is tilted leftward as shown in FIG.  12 . Thus, the slider  155  slides together with the valve member  160  toward the beer supply pipe  134 , and the first valve element  170  retracts from the valve seat  137 , as shown in the enlarged view of a pertinent portion. Therefore, beer flows from the beer supply pipe  134  successively into the liquid passage  138  and the passage  148  of the liquid pouring nozzle  143  to be poured into a mug (not shown). 
     In this state, or in the state where the large diameter portion  172  of the valve member  160  has slid toward the valve seat  137 , the communication between the annular groove  178  and the air vents  149   a  and  149   b  is interrupted. Thus, there occurs no introduction of the outside air into the liquid pouring nozzle  143  through the air vents  149   a  and  149   b , preventing excessive frothing which can be caused by migration of air in pouring beer. 
     When the lever  132  is returned to the neutral position so as to stop pouring of beer, the pouring spout resumes the state shown in FIG. 9, where the annular groove  178  opposes the air vents  149   a  and  149   b . Thus, the outside air is introduced into the liquid pouring nozzle  143  to purge the beer remaining in the liquid pouring nozzle  143  to the outside. 
     Next, the lever  132  is tilted rightward in FIG. 14 so as to pour froth into the mug. This causes the slider  155  to slide leftward against the resilience of the resilient part  157  as shown in the enlarged view of a pertinent portion in FIG.  15 . Here, the first valve element  170  is pressed against the valve seat  137  by the liquid pressure of the beer, so that the valve member  160  is located at a position where it cannot slide leftward any more. In other words, when the lever  132  is tilted rightward, the slider  155  slides leftward to cause the sealing piece  163  to retract from the second valve element  173  and opens the opening  175   a  of the narrow hole  175 . 
     Thus, the beer in the beer supply pipe  134  flows into the bottomed through hole  174  opening to the head end face of the first valve element  170  to be jetted through the opening  175   a  of the narrow hole  175 . The narrow hole  175  is designed to have a diameter as very small as that of an orifice, so that beer is jetted out vigorously to impinge against the valve seat or sealing piece  163  opposing the narrow hole  175 . Thus, the beer is converted into find froth. The froth having no other channel to go flows downward along the annular groove  146  from the top thereof, whereas the impetus of the froth is attenuated. The froth then enters the passage  145  of the froth pouring nozzle  144  and is poured as additional froth over the top of the beer contained in the mug. The froth flowing down along the annular groove  146  is sealed from the resilient part  157  by the slider  155  sliding within the liquid passage  138  in intimate contact therewith, so that froth is prevented from dwelling in the space where the resilient part  157  is housed. 
     Further, at the time of pouring froth, the slider  155  capable of sliding within the liquid passage  138  in intimate contact with the internal surface of the passage  138  is caused to approach the stopper  156  that is regulated not to move by the first valve element  170  pressed against the valve seat  137  of the first valve element  170 , as shown in FIG. 15, reducing the volume of the housing space S in which the resilient part  157  interposed between the slider  155  and the stopper  156  is housed. The housing space S communicates with the passage  145  of the froth pouring nozzle  144  through the communicating passage  179 , so that when the air present in the housing space S is compressed, the air is exhausted through the communicating passage  179  into the passage  145  of the froth pouting nozzle  144 . In other words, the air in the housing space S is not exhausted to the outside of the spout body  131  along the external surface of the stopper  156 , preventing leakage of froth or beer together with the air and contamination of the external surface of the spout body  131 . 
     In this embodiment, the position of the annular groove  146  is staggered from the location of the passage  145  in the froth pouring nozzle  144  toward the expanded portion  141  so as to prevent the beer jetted out through the thin hole  175  and impinged against the sealing piece  163  from flowing in the form of strong current directly into the froth pouring nozzle  144 . Therefore, the impetus of the froth entering the nozzle  144  is further attenuated. Thus, even if the froth pouring nozzle  144  is short, the froth does not form turbulence when it is poured but forms a laminar flow to flow down the froth pouring nozzle  144 . In other words, there is no need of increasing the length of the froth pouring nozzle  144  in order to attenuate the impetus of the froth, but the nozzle  144  can be allowed to have the smallest possible length, thus reducing after dripping of froth (to be described later). 
     When the lever  132  is returned to the neutral position so as to stop pouring of froth, the pouring spout resumes the state as shown in FIG. 9, where the slider  155  is resiliently urged by the resilient part  157  to press the sealing piece  163  against the second valve element  173 , and the sealing piece  163  closes the thin hole  175 . After formation of froth is stopped, there remains some froth within the annular groove  146  and in the passage  145  in the froth pouring nozzle  144 , i.e., some froth remains in the froth channel. However, the residual froth is present in a small amount and has a small dead weight and a high viscosity, the froth remains adhered for a while in the annular groove  146  and in the passage  145  of the froth pouring nozzle  144 . Incidentally, when the housing space S for the resilient part  157  resumes the original volume, air is introduced into the housing space S through the froth pouring nozzle  144  and the communicating passage  179 . 
     After dwelling for a while in the froth flow channel, the froth disintegrates to resume the liquid form and drips as such, so that the froth left in the channel after the previous froth pouring operation does not drop as such but, if dropped, in the liquid form. The amount of the resulting liquid if any is very small, and it merely drops into a mug without undergoing frothing after beer is poured into the mug, causing no excessive frothing. Therefore, there is no need of securing waiting time until the next beer pouring operation, but beer can be poured into another mug immediately after completion of the froth pouring operation. Meanwhile, the beer froth deposited on the internal surface of the annular groove  146  of the spout body  131  and that of the passage  145  of the froth pouring nozzle  144  is poured together with the froth to be formed in the next froth pouring operation, so that there is no froth remaining in the froth channel for a long time to cause no deterioration of beer. 
     Further, as described above, the sparkling beverage pouring spout  130  of this embodiment is of the structure where the housing space for the coiled spring as the resilient part  157  is not exposed to the froth channel for pouring froth into a mug. Therefore, this structure is more hygienic than the conventional structure, since large amounts of froth and beverage formed after liquefaction of froth are prevented from remaining deposited on the coiled spring having many clearances. Meanwhile, the pouring spout  131  can be cleaned easily, since the valve rod assembly  133  can be drawn out from the spout body  131  as an integral body merely by removing the female screw  135  and the lever  132 . 
     It should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. 
     In the embodiment described above, the pouring spout is of the structure where the froth pouring nozzle and the housing space for the resilient part communicate with each other. However, in a structure of sparkling beverage pouring spout, where only a sparkling beverage is poured in the form of liquid without additional pouring of froth, there may be employed a constitution, in which the housing space for the resilient part and the liquid pouring nozzle providing a liquid channel communicate with each other through a communicating channel. Further, this constitution can also be applied to a sparkling beverage pouring spout of the constitution where both a liquid and froth thereof is poured through a single nozzle. 
     Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope of the appended claims.