Device for limiting the filling of a tank with fuel

Abstract: A device for automatically limiting the filling of a tank with fuel, particularly with liquefied petroleum gas, comprising a body (1;33) provided with a duct (2;34) which can be connected to a fuel supply; a seat (5;35) which has an intake port (6) which is connected to the duct and a discharge port (11a) which is connected to the inside of the tank; a first plug element (18;41) and a second plug element (15;49) which are accommodated in the seat and are adapted to control the intake and discharge ports. Two springs (21;22) are arranged between the plug elements and the body of the device and keep the first plug element in the position for closing the intake port when the duct is not connected to the fuel supply. A cam (32;46) is operatively associated with the second plug element (15;49) and is controlled by a detector (31;48) for detecting the level of the fuel inside the tank. During filling and until the preset level is reached, the cam means keep the plug element in the position for the flow of fuel into the tank, while when the preset level is reached, the plug element is actuated into the position for closing the discharge port.

Description: The present invention relates to a device for automatically limiting the filling of a tank with fuel, particularly with liquefied petroleum gas (LPG). Currently applicable statutory provisions concerning the containment of liquefied petroleum gas in a vessel in general and in a motor vehicle tank in particular prohibits filling said tank to a volume of more than 80% of the nominal volume of the vessel. This limitation forces manufacturers of filling devices to provide adapted solutions in order to comply with the above value. For instance, US Patent 4,444,230 discloses a device for limiting the filling of the tank, provided with valve means for impeding a fluid flow according to a pressure difference between the incoming fluid and the fluid already stored in the tank. However, conventional devices suffer severe shortcomings which can lead to the complete filling of the tank, causing an explosion hazard in case of volume increase due to heat. These shortcomings are mainly due to the fact that the valve for feeding the LPG into the tank can assume a position which is intermediate between the closed position and the open position and allows LPG to flow into the tank when the supply flow-rate is low due to insufficient pressure difference between the filling pump and the tank or due to manual (i.e., intentional) limiting of the supply flow-rate by acting on the filling nozzle. The aim of the present invention is to provide a device which allows to obviate the above described drawbacks of conventional devices. Within the scope of this aim, an object of the present invention is to provide a device which is structurally simple, reliable in operation and flexible in use in relation to the possibility of installing it instead of currently commercially available devices. This aim, this object and others which will become apparent hereinafter, are achieved with a device for automatically limiting the filling of a tank with fuel, particularly with liquefied petroleum gas, whose characteristics are defined in the claims. Further characteristics and advantages will become apparent from the following description on the basis of the accompanying drawings, wherein: Figure 1 is a partially sectional view of a first embodiment of the device according to the present invention; Figure 2 is a sectional view, taken along the plane II-II of Figure 1; Figure 3 is a sectional view of another embodiment of the device; and Figure 4 is a view of the device of Figure 3 in a different operating condition. With reference to the above figures, 1 designates the body of the device of the present invention, which is applied to a tank for containing fuel, particularly liquefied petroleum gas. A duct 2 is formed in the body 1 and is provided with a coupling which allows connection to a nozzle for dispensing fuel (for example liquefied petroleum gas) when the tank is to be filled. The coupling has a closure valve 3 which controls the connection between the filling nozzle and the tank. The body 1 has a shank 4 which protrudes into the tank and in which there is a cylindrical seat 5 which is connected to the duct 2 through a hole defining a circular opening 6 hereinafter termed intake port. A tubular element 7 is screwed into the seat 5 and extends the cylindrical seat 5. The tubular element 7 has a bottom 8 in which there is a hole 9 which is coaxial to the circular intake port 6. A slot 10 is formed in the peripheral wall of the tubular element 7, proximate to the bottom 8, and is connected to the inside of the tank. The tubular element 7 has a smaller inside diameter than the seat 5 and therefore its upper edge forms an annular shoulder 11 which surrounds a discharge port 11a. A stem 12 is guided in the hole 9 and a blind sleeve 13 is rigidly coupled to the top of the stem. The sleeve is arranged coaxially inside the tubular element 7 and forms, together with said tubular element, a tubular interspace 14 which connects the seat 5 to the slot 10 through the discharge port 11a. The sleeve 13 has, at the end that lies furthest from the stem 12, a flange 15 having an outside diameter which is smaller than the outside diameter of the seat 5, so that a circular gap remains between the peripheral edge of the flange and the inside wall of the seat 5. The flange 15 is adapted to abut against the shoulder 11 in order to act as a plug element to interrupt the connection between the seat 5 and the interspace 14. A stem 16 is slidingly inserted in the sleeve 13, and a square plate 17 is rigidly coupled to the end of the stem that lies outside the sleeve; the corners of said square plate are in sliding contact in the seat 5. A tang 18 protrudes from the plate 17, coaxially to the stem 16, and constitutes a plug element which, together with the plate 17, forms an annular groove in which a sealing ring 19 is accommodated. The tang 18 enters the intake port 6 so as to close it hermetically, except for possible. negligible seepages, or so as to clear it after performing a stroke having a preset extent. The sealing ring 19 is adapted to abut against a shoulder 20 which is formed by the seat 5 together with the edge of the intake port 6, so as to act as a one-way plug element which prevents the fuel from returning from the seat 5 back into the duct 2. On the stem 12, between the bottom 8 of the tubular element 7 and the sleeve 13, there is a spring 21 which acts on the sleeve 13 so as to keep the flange 15 spaced from the shoulder 11. An additional spring 22 is arranged inside the sleeve 13 and acts on the stem 16 so as to keep the ring 19 in abutment against the shoulder 20. The spring 21 is weaker than the spring 22 and its elastic constant is such as to ensure the return of the ring 19 into the position for closing the intake port 6 and the lifting of the flange 15 from the shoulder 11 when the pressure in the duct 2 is equal to, or lower than, the pressure in the seat 5. Vice versa, when the pressure is higher, the plate 17 and the sleeve 13 are actuated so as to compress the springs 21 and 22 and push out the stem 12 through the hole 9 of the bottom 8. The protrusion of the stem 12 depends on the position of an element 23 against which the stem 12 is actuated. Said element, see also Figure 2, is constituted by a cylinder 24 which is supported rotatably in an angle bracket 25 which cantilevers out from the bottom 8. The angle bracket is substantially U-shaped, and the seats for rotatably supporting the cylinder 24 are formed in its wings 26 and 27. The wings 26 and 27 are connected by a flat element 28 in which there is a slot 29 which is elongated in the direction of rotation of the cylinder. A rod 30 is guided through the slot 29, and one end of said rod is rigidly inserted in the cylinder 24. A floater 31 for detecting the level of the fuel inside the tank is fixed to the other end of the rod 30, so that fuel level variations produce a rotation of the cylinder 24. The cylinder 24 comprises a cam, which is constituted by a sector 32 formed by partially milling the cylinder and protrudes axially below the bottom 8 so as to cooperate, by means of its outer surface, with the stem 12. The cam 32 has a preset angular extension which is a function of the volume of the tank that must be left empty. The operation of the described device is as follows. If the tank is empty, the device is in the position shown in Figure 1, in which due to the springs 21 and 22 the tang 18 closes the intake port 6, with the ring 19 in abutment in the shoulder 20, and the floater 31, by means of the rod 30, keeps the cam 32 in the position in which it interferes with the stem 12. When fuel is to be introduced, for example liquefied petroleum gas (LPG), into the tank, the filling nozzle is connected to the body 1. The pressure of the LPG spaces the ring 19 from the shoulder 20 and makes the tang 18 slide in the intake port 6 in contrast with the return action applied by the spring 22. During this step, the pressure applied by means of the spring 22 to the sleeve 13 is ineffective, since the stem 12 is prevented from protruding from the bottom 8 by abutment against the cam 32. Accordingly, the flange 15 cannot move down to close the discharge port 11a. When the tang 18 has performed a sliding movement such that it protrudes from the intake port 6, so that a circular opening forms between the tang 18 and the shoulder 20, the LPG can flow into the tank through the opening 6, the seat 5, the interspace 14 and the opening 10. As the level of the fuel in the tank rises, the floater 31 also rises and, by means of the rod 30, turns the cam 32. When the chosen level has been reached and the cylinder 24 has performed the corresponding rotation, the cam 32 disengages the stem 12, which can accordingly move downwards, making the flange 15 rest against the shoulder 11 and interrupting the flow of LPG into the tank through the discharge port 11a, the interspace 14 and the opening 10. The described device perfectly achieved the intended aim and object. In particular, it should be noted that the volume of fuel introduced in the tank is defined exactly by the angular position assumed by the cam 32 and cannot be altered by adjusting the filling pressure or by actions of the filling operator. When the level of the fuel in the tank has reached the chosen value, so that the stem 12 no longer abuts against the cam 32, any further supply of fuel at reduced pressure, due to the greater rigidity of the spring 22 with respect to the spring 21, in fact makes the flange 15 close the discharge outlet 11a before the tang 18 protrudes from the opening 6, thus making it impossible for fuel to flow into the tank. The device is susceptible of numerous modifications and variations. In particular, the return spring 21 of the sleeve 13, instead of being interposed between the bottom 8 and the bottom of the sleeve 13, can be arranged in the tubular interspace 14 and can act between the bottom 8 and the flange 15. Another embodiment of the device which is technically equivalent to the one shown in Figures 1 and 2 is shown in Figures 3 and 4 in two different operating conditions. With reference to Figures 3 and 4, the reference numeral 33 designates the body of the device, which is applied to a tank for containing fuel and particularly liquefied petroleum gas. A duct 34 is formed in the body 33 and leads into a cylindrical seat 35 whose axis is designated by A; said duct is provided with a coupling which allows connection to a nozzle for dispensing fuel (for example liquefied petroleum gas) when the tank is to be filled. The coupling has a closure valve (not shown) which blocks the connection between the filling nozzle and the tank. A cylindrical portion 36 is associated with the body 33 and is hereinafter term "tang" for convenience in description; said tang closes the seat 35 with one of its faces 37. An annular groove is formed in the face 37, concentrically to the axis A, and a sealing ring 38, made of rubber-like material, is recessed in said groove and protrudes from the face 37. An axial hole 39 leads into the area delimited by the ring 38 and constitutes a transfer duct which connects the seat 35 to an annular chamber 40 formed in the tang 36 concentrically to the axis A. The seat 35 accommodates a cylindrical body 41, which constitutes a first plug element 41 for controlling the flow of fuel through the transfer duct 39. The plug element 41 is rotationally rigidly coupled to a rod 42, which passes through it and is rotatably supported in a hole 43 of the body 33 and in a hole 44 which passes through the tang 36 along the axis A. A pin 46 protrudes from the face 45 of the plug element 41 that is directed toward the face 37 of the tang 36; its distance from the axis A is equal to the distance of the transfer duct 39, and its diameter is such that it can engage in said transfer duct when the plug element 41 has assumed a given angular position, with respect to the tang 36, which corresponds to the maximum amount of fuel to be introduced in the tank. The amount of fuel in the tank is detected by a level transducer, which is composed of the rod 42, of an arm 47 which protrudes radially from the rod 42, and of a floater 48 for detecting the level reached by the fuel inside the tank. A cup 49 is slidingly superimposed on the tang 36 and comprises a bottom 50, through which the rod 42 passes, and a cylindrical wall 51 which is guided on the tang 36. The cup 49 constitutes a second plug element for controlling the outlet of the transfer duct 39. The bottom 50 of the cup 49 forms, together with the bottom 52 of the tang 36, a compensation chamber 53 which is constantly connected to the chamber 40 through a hole 54 of the bottom 52. On the rod 42, outside the bottom 50, there is a ring 55 which is fixed by means of a grub screw 56 and acts as abutment for a spring 57 which acts by compression against the cup 49 so as to actuate it into a position in which it abuts against the flange 58 and produces the external closure of the chamber 40 and therefore of the duct 39. The described device is completed by a second spring 59, whose elastic constant is lower than that of the spring 57 and which is partly accommodated in a recess 60 of the tang 36 and partly accommodated in a recess 61 of the plug element 41. The operation of the described device is as follows. If the tank is empty, the device is in the position shown in Figure 3, in which by virtue of the action of the springs 57 and 59 the cup 49 closes the chamber 40 and the plug element 41 is actuated against the face 37. Since the floater 48, by means of the arm 47 and the rod 42, keeps the plug element 41 in an angular position in which the pin 46 abuts against the face 37, the duct 34 is connected to the transfer duct 39 through the seat 35. Fuel, for example liquefied petroleum gas (LPG), is introduced in the tank by connecting the filling nozzle to the body 33. The pressure of the LPG spaces the cup 49 from its abutment against the flange 58, in contrast with the return action applied by the spring 57. When the cup 49 has performed a sliding motion which opens the chamber 40 onto the outside, the LPG that arrives from the duct 34 can flow into the tank through the seat 35, the transfer duct 39 and the chamber 40. As the level of the fuel in the tank rises, the floater 48 also rises and, by means of the rod 47, 42, turns the plug element 41. When the chosen level has been reached and the plug element 41 has performed the corresponding rotation, the pin 46, by virtue of the return action of the spring 57, engages the duct 39, making the plug element rest against the sealing ring 38 and closing the duct 39, thus interrupting the flow of LPG into the tank through the duct 39 and the chamber 40. In particular, it should be noted that the volume of fuel introduced in the tank is defined exactly by the angular position assumed by the plug element 41 and cannot be altered by adjusting the filling pressure or by actions of the filling operator. When the level of the fuel in the tank has reached the chosen value, so that the pin 46 has engaged the duct 39, any further supply of fuel at reduced pressure has no effect on the closed position of the plug element, since said plug element is affected not only the traction of the spring 57, which is stronger than the spring 59, but also by the pressure of the supplied fuel. In the device of Figures 3 and 4, the pin 46, instead of engaging the transfer duct 39, can also engage a dead hole formed in the face 37. The disclosures in Italian Patent Applications No. BO97A000537 and No. BO97A000616 from which this application claims priority are incorporated herein by reference. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims: A device for automatically limiting the filling of a tank with fuel, particularly with liquefied petroleum gas, comprising: a body (1; 33), provided with a duct (2;34) which can be connected to a fuel supply; a seat (5; 35), which can be connected to said duct (2; 34); a first plug element (18; 41), which is slidingly accommodated in said seat (5; 35) and is adapted to control the flow of fuel through said duct (2; 34); a second plug element (15; 49), which can move with respect to said first plug element and is adapted to control the flow of fuel into said tank; characterised in that the device further comprises a tubular or cylindrical element (7; 36) which extends said cylindrical seat (5; 35), and an opening (10; 40), formed in the peripheral wall of said tubular or cylindrical element (7; 36) for the passage of fluid from the seat (5; 35) to the tank, said plug elements (15, 18; 41, 49) being operatively associated by spring means (21, 22; 57, 59) which are adapted to keep one of said plug elements in the position for blocking the flow of fuel when said duct (2) is not connected to the fuel supply; cam means (32; 46) being also provided which are operatively associated with one of said plug elements (15, 18; 41, 49) and are controlled by a detector (31; 48) for detecting the level of the fuel inside the tank, so that during filling and until the preset level is reached, said cam means keep said plug elements in the position for the flow of fuel into the tank, while when the preset level is reached, said plug elements are actuated into the position for blocking a discharge port provided between said seat (5; 35) and said opening. A device according to claim 1, characterized in that said seat (5) is provided with an intake port (6) which is connected to said duct (2); in that said second plug element (15) is accommodated in said seat (5), can slide coaxially to said first plug element (18) and is adapted to control said discharge port (11a); said spring means comprising a first spring (22), which acts between said plug elements (18, 15), and a second spring (21), which acts between said second plug element (15) and an abutment of said seat, said springs (22, 21) being adapted to keep said first plug element (18) in the position for closing said intake port (6) when said duct (2) is not connected to the fuel supply. A device according to claim 2, characterized in that said first plug element (18) is constituted by a plate (17) which is guided in said seat (5), an axial tang (18) protruding from a face of said plate and being adapted to hermetically engage said intake port (6) along a certain extent, a stem (16) protruding from the opposite face, said stem (16) being coaxial to said tang (18) and being able to slide in a blind sleeve (13) which is guided in said tubular element (7) which is associated with said body (1) coaxially to said seat (5), a sealing ring (19) being arranged around said tang (18) on said plate (17) in order to close said intake port (6), said tubular element (7) comprising an annular shoulder (11) which surrounds said discharge port (11a), said sleeve (13) having, at one end, a flange (15) which is adapted to abut against said shoulder (11) in order to close said discharge port (11a) and having, at the opposite end, a stem (12) which can slide in said tubular element (7) and cooperates with said cam (32); a tubular interspace (14) being provided, between said sleeve (13) and said tubular element (7), for the discharge of fuel into the tank through slots (10) of said tubular element (7); a first spring (22) being accommodated in said sleeve (13) and acting between said sleeve and the stem (16) of said plate (17) and a second spring (21) which acts between said sleeve (13) and said tubular element (7); said second spring (21) having a lower elastic constant than said first spring (22). A device according to claim 3, characterized in that said second spring (21) is accommodated in said interspace (14) and acts between said flange (15) and said tubular element (7). A device according to claim 4, characterized in that said cam (32) is constituted by a sector of a cylinder (24) which is supported in said tubular element (7) so that it can rotate about an axis which is perpendicular to the axis of the stem (12) of said sleeve (13), a rod (30) being radially rigidly coupled to said cylinder (24), a detector (31) being fixed to said rod to detect the level of the fuel inside the tank; said cam (32) being able to rotate between a first angular position, in which the stem (12) of said sleeve (13) abuts against it to prevent said flange (15) from abutting against said shoulder (11) and closing said discharge port (11a), and a second angular position, in which said stem (12) does not abut against said sector, allowing said stem (12) to perform a movement which allows the flange (15) to close said discharge port (11a). A device according to claim 1, characterized in that it further comprises a fuel transfer duct (39), which is formed in said cylindrical portion (36) to connect said seat (35) to the inside of said tank; said plug elements comprising a first plug element which is slidingly and rotatably accommodated in said seat (35); a control element in a given angular position of said first plug element (41) allowing said first plug element to move into a position for closing the inlet of said transfer duct (39); and a second plug element (49), which is slidingly supported on said cylindrical portion (36) coaxially to said first plug element (41) and is adapted to control the outlet of said transfer duct (39); said detector (48) for transducing the level of the fuel inside the tank being operatively associated with said first plug element (41) so as to actuate the rotation thereof until said preset angular position is reached; a first spring (59), which acts between said first plug element (41) and said cylindrical portion (36), and a second spring (57), which acts on said second plug element (49), said springs (57, 59) being adapted to keep said second plug element (49) in the position for closing said transfer duct (39) and said first plug element (41) in the position for connecting said transfer duct (39) to said seat (35) when said seat (35) is not connected to the fuel supply; said first plug element (41) being controlled by said detector (48) so that during filling and until the preset level is reached, the pressure of the fuel retains said first plug element (41) in the position for the flow of the fuel through said transfer duct (39), while when the preset level is reached, said detector (48) places said first plug element (41) in the position for blocking said transfer duct (39). A device according to claim 6, characterized in that said fuel level detector (48) is composed of a rod (42) which is rotatably and slidingly supported in said cylindrical portion (36) and has an end which protrudes into said seat (35) and is rotationally rigidly coupled to said first plug element (41) and an opposite end which is provided with a radial arm (47). A device according to claim 7, characterized in that said first plug element (41) is provided with a pin (46) for abutment against a wall (37) of said seat (35), which is adapted to engage a recess of said wall (37) in order to allow the sliding of said first plug element (41) into a position for closing the inlet of said transfer duct (39). A device according to claim 8, characterized in that an annular groove is formed in said wall (37), concentrically to the rod (42) of the detector (48), a sealing ring (38) being recessed in said groove, said ring delimiting an area in which the inlet of said transfer duct (39) is located, said first plug element (41) having a face which is adapted to abut against said ring in order to close said inlet. A device according to claim 8, characterized in that said recess in which said pin (46) engages is the transfer duct (39).

Inventors: REGAZZI RENZO, REGAZZI, RENZO
Applicants: OMVL SRL, O.M.V.L. S.R.L.
Application year: 1998
Main classification: F16K31
IPC codes: F17C13, F16K31