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(11) | EP 3 248 932 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | MACHINE FOR FILLING CONTAINERS WITH AUTOMATIC REFILL SYSTEM |
| (57) The present invention relates to a filling machine of the weight type, and more precisely
to a system for refilling the filling liquid in the supplying tank of the machine. In particular, the invention relates to a weight filling machine comprising a filling unit and a unit for supplying a container-filling liquid to the filling unit, wherein the supply unit comprises a tank containing the filling liquid from which a dispensing duct (14) departs, characterized in that the dispensing duct (14) leads into an automatic refill device (15) comprising a receptacle (16) in turn connected to the filling unit (2) by means of a supply line (11) of the filling liquid, wherein the dispensing duct (14) terminates inside the receptacle (16) with a float valve (17) for closing-opening the dispensing duct (14), wherein the float valve (17) determines and adjusts the level of filling liquid inside the receptacle (16). |
[0001] The present invention relates to a filling machine of the weight filling type, and more precisely to a system for refilling the filling liquid in the supplying tank of the machine.
[0002] Filling machines typically comprise a carousel which moves a plurality of containers to be filled and a plurality of filling taps, placed on the vertical axis of the containers, adapted to dispense the filling liquid into the containers. The machine further comprises a high capacity tank containing the filling liquid, which is placed at a certain height above the manifold which distributes the liquid among the various taps, so that the liquid outflows from the taps with a dispensing speed which is given by the following formula:
where g is the gravity acceleration and h is the height measured between the liquid dispensing point and the liquid level in the tank.
[0003] During the dispensing, the tank tends to empty, and the level to decrease, which would alter the filling speed. Therefore, the tank comprises a refill system, which is adjusted so as to maintain the level of liquid in the tank substantially constant at all times. However, such a refill system is complex and requires the use of sophisticated detection means, such as level sensors and/or command and control units adapted to adjust the refilled liquid amount as a function of that dispensed by the machine.
[0004] Therefore, it is the object of the present invention to provide a filling machine which allows a simplified management of the tank refilling system with filling liquid.
[0005] Such an object is achieved by a filling machine as set forth in the appended claims, the definitions of which form an integral part of the present description.
[0006] In particular, the invention relates to a weight filling machine comprising a filling unit and a unit for supplying a container-filling liquid to the filling unit, wherein the supply unit comprises a tank containing the filling liquid from which a dispensing duct departs, wherein the dispensing duct leads into an automatic refill device comprising a receptacle in turn connected to the filling unit by means of a supply line of the filling liquid, wherein the dispensing duct terminates inside the receptacle with an automatic valve, preferably a float valve, for closing-opening the dispensing duct, wherein the automatic valve determines and adjusts the level of filling liquid inside the receptacle.
[0007] Further features and advantages of the present invention will become more apparent from the description of some embodiments, given below by way of indicative and non-limiting example, with reference to the following figures:
Figure 1 shows a schematic block diagram view of the filling machine of the invention;
Figures 2A and 2B depict schematic views of a detail of the machine in Figure 1 in two different operating conditions;
Figure 3 shows a schematic block diagram view of the filling machine of the invention according to a different embodiment.
[0008] With reference to Figure 1, the filling machine according to the invention, indicated as a whole by numeral 1, comprises a filling unit 2 and a supply unit 3 of a liquid product for filling containers.
[0009] The filling unit 2 comprises a rotating table 4 hinged on a shaft 5 moved by the motorization of the machine. The rotating table 4 comprises a plurality of plates 6 for supporting containers C. The containers C may be retained on the plates 6 in a conventional manner, for example by retaining them at the neck 7 by means of suitable pliers.
[0010] Above each plate 6, a filling valve 8 is positioned, also of the conventional type, chosen according to the type of filling liquid (e.g. for foaming products, or for high density products, etc.).
[0011] Preferably, the filling unit 2 is a weight filling unit, therefore it is equipped with suitable devices, of the conventional type, which allow this type of filling. In particular, the plates 6 or pliers 7 (if container C is suspended at the pliers 7) will be connected to a suitable loading cell which in turn will be operatively connected to a command and control unit (not shown) of machine 1 so as to stop the filling of each individual container C once the preset weight has been reached.
[0013] The plurality of distribution lines 9 is connected to a distribution manifold 10 which distributes the product among the various filling valves 8. The constructional details of the distribution manifold 10 are known to those skilled in the art since such a manifold is used in conventional filling machines.
[0015] The supply unit 3 comprises a tank 12 containing the filling liquid. The tank may be periodically filled by means of a loading line 13 which may be connected to a tank or storage silos, for example.
[0016] Tank 12 comprises a dispensing duct 14, typically placed at the bottom to allow the outflow of the liquid by gravity. The dispensing duct 14 leads into an automatic refill device 15, in turn connected along with the supply line 11 of the filling liquid to the distribution manifold 10 of the filling unit 2.
[0017] The automatic refill device 15, in particular the surface of the liquid inside such a device, is placed at a lower height with respect to the level at which the dispensing nozzles of the filling valves 8 are placed. As shown in Figure 1, the filling liquid should thus overcome a geodetic difference in level h1 so that the dispensing of the liquid may take place. This feature allows to obtain a better control of the filling operation. The automatic refill device 15 is preferably placed on the floor.
[0018] As shown in Figures 2A and 2B, the automatic refilling device 15 comprises a receptacle 16, the supply line 11 of the filling unit 2 departing from the bottom thereof.
[0019] Receptacle 16 may have a cylindrical shape, but other shapes, such as an ovoid shape or a spherical shape, are not excluded.
[0020] The upper surface 16a of receptacle 16 comprises an opening, positioned for example in a central position, in which the dispensing duct 14 originating from tank 12 is inserted. The dispensing duct 14 then comprises an end portion 14a inside the receptacle, which terminates with an automatic valve, such as a float valve 17 or a diaphragm valve.
[0021] In certain embodiments, the float valve 17 comprises a bell 18 with its cavity facing downwards forming the lower end of the end portion 14a of the dispensing duct 14. In bell 18, a float 19 is accommodated, for example a spherical float, free to move between a closing position and an opening position of duct 14, respectively shown in Figures 2A and 2B.
[0022] The float valve 17 thus defines the level of liquid present in receptacle 16. Receptacle 16 then comprises a headspace 20 which remains free at all times from the filling liquid. At such a headspace 20, receptacle 16 comprises an opening 21 connected to a pipe 22 in flow communication with a source 23 of air or another gaseous fluid (e.g., an inert gas if the filling liquid is sensitive to oxygen) at a first predetermined pressure P1.
[0023] The pressure to which the filling liquid exiting the dispensing duct 14 is instead subjected and which therefore acts on the float valve 17 is instead dictated by height h according to the law:
where P is the static pressure, p is the liquid density, g is the gravity acceleration, and h is the height of the liquid surface in tank 12 from the float valve 17.
[0024] In the automatic refill device 15 of the invention, the pressure P of the filling fluid exiting the dispensing duct 14 is higher than the first pressure P1 of the gas in the headspace 20, but lower than a second pressure P2 given by the sum of the first pressure P1 of the gas with Archimedes' thrust to which the float 19 is subjected. The latter is equal to the weight force of float 19:
where m is the mass of float 19 and g is the gravity acceleration.
[0025] Furthermore, the pressure P1 of the gas in the headspace must be equal to or higher than the pressure Pa required to overcome the geodetic difference in level h1, according to the equation Pe= ρgh1.
[0026] Thereby, in static conditions, i.e. in a period of standstill of the filling machine 1, the automatic refill device 15 is in the condition shown in Figure 2A: the pressure P2 resulting from the sum of Archimedes' thrust with the pressure P1 of the gaseous fluid keeps float 19 in the closing position.
[0027] When the machine is in the condition of use, i.e. during the step of filling the containers C, the level of the filling liquid in receptacle 16 tends to decrease due to the liquid which is removed through the supply line 11, and this causes the lowering of float 19 to the opening position (Figure 2B). Due to the pressure P of the input liquid being greater than the pressure P1 of the gaseous fluid, the filling liquid flows through the dispensing duct 14 and brings the level inside the receptacle 16 back to the starting position. Float 19 thus closes the dispensing duct 14 and the raising of the level halts. Continuing the filling operation, the above-described operating conditions are alternately recreated, i.e. a continuous and rapid alternation of the condition in Figure 2A and that in Figure 2B. Thereby, an automatic refilling of receptacle 16 is thus obtained.
[0028] The fact that the volume of receptacle 16 is sufficiently small so as to result in a greater sensitivity and speed of the response time of the automatic adjustment is advantageous. For example, receptacle 16 may have a volume of 3-7 liters.
[0029] In a different embodiment, shown in Figure 3, the pressure P of the fluid exiting the dispensing duct 14 is determined by pumping means 24 for loading the filling liquid in receptacle 16.
[0030] Along the dispensing duct 14, between such pumping means 24 and the receptacle 16, valve means 25 are placed, typically a pressure limiter, connected to a recirculation duct 26 which reconnects to the dispensing duct 14 upstream of the pumping means 24.
[0031] In this embodiment, if the pressure P of the filling liquid exiting the dispensing duct 14 should overcome the predetermined threshold, the valve means 25 would divert the liquid flow into the recirculation duct 26.
[0032] Therefore, the filling machine according to the invention allows to achieve the intended objects.
[0033] Indeed, the automatic refill system of the invention does not require sophisticated electronic controls, such as level sensors and the like, thus obtaining the adjustment of the level in the refill device 15 in a totally mechanical manner.
[0035] It is apparent that only some particular embodiments of the present invention have been described, to which those skilled in the art will be able to make all those modifications required for the adaptation thereof to particular applications, without thereby departing from the scope of protection of the present invention.
1. Weight filling machine (1) comprising a filling unit (2) and a unit (3) for supplying
a liquid for the filling of containers (C) to the filling unit (2), wherein the supply
unit (3) comprises a tank (12) containing the filling liquid from which a dispensing
duct (14) departs, characterized in that the dispensing duct (14) introduces filling liquid in an automatic refill device
(15) comprising a receptacle (16) in turn connected to the filling unit (2) by means
of a supply line (11) of the filling fluid, wherein the dispensing duct (14) terminates
inside the receptacle (16) with an automatic valve (17) for the closing-opening of
the dispensing duct (14), wherein the automatic valve (17) determines and adjusts
the level of filling liquid inside the receptacle (16).
2. Weight filling machine (1) according to claim 1, wherein the automatic valve is a
float valve (17).
3. Weight filling machine (1) according to claim 1 or 2, wherein the filling unit comprises
a plurality of filling valves (8) each comprising a dispensing nozzle and wherein
the surface of the liquid inside the receptacle (16) is placed at a lower height with
respect to the level at which the dispensing nozzles of the filling valves (8) are
placed, such that the filling liquid must overcome a geodetic difference in level
(h1).
4. Weight filling machine (1) according to claim 2 or 3, wherein the float valve (17)
comprises a bell (18) with cavity facing downwards constituting the lower end of the
end portion (14a) of the dispensing duct (14), a float (19) being housed in the bell
(18), such float is free to move between a closing position and an opening position
of the dispensing duct (14).
5. Weight filling machine (1) according to any one of claims from 1 to 4, wherein the
receptacle (16) comprises a headspace (20) that remains free from filling liquid at
all times, in which, at such headspace (20), the receptacle (16) comprises an opening
(21) in flow communication with a source (23) of air or other gaseous fluid at a first
predetermined pressure (P1).
6. Weight filling machine (1) according to claim 5, wherein the filling liquid coming
out of the dispensing duct (14) has a pressure (P) according to the law:
where P is the static pressure, p is the liquid density, g is the gravity acceleration and h is the height of the surface of the liquid in the tank (12) from the float valve (17), and wherein said pressure (P) of the filling fluid is greater than the first pressure (P1) of the gas in the headspace (20), but lower than a second pressure (P2) given by the sum of the first pressure (P1) of the gas with Archimedes' thrust which the float (19) is subjected to, said Archimedes' thrust being equal to the weight force (Fp) of the float (19) according to the law:
where m is the mass of the float (19) and g is the gravity acceleration.
where P is the static pressure, p is the liquid density, g is the gravity acceleration and h is the height of the surface of the liquid in the tank (12) from the float valve (17), and wherein said pressure (P) of the filling fluid is greater than the first pressure (P1) of the gas in the headspace (20), but lower than a second pressure (P2) given by the sum of the first pressure (P1) of the gas with Archimedes' thrust which the float (19) is subjected to, said Archimedes' thrust being equal to the weight force (Fp) of the float (19) according to the law:
where m is the mass of the float (19) and g is the gravity acceleration.
7. Weight filling machine (1) according to any one of claims from 5 to 6, wherein the
pressure (P1) of the gas in the headspace (20) is equal to or greater than the pressure
(Pa) required to overcome the geodetic difference in level (h1), according to the equation
Pe= ρgh1, wherein ρ is the density of the liquid, g is the gravity acceleration and
h1 is said geodetic difference in level.
8. Weight filling machine (1) according to any one of claims from 1 to 7, wherein the
dispensing duct (14) is intercepted by pumping means (24) for loading the filling
liquid in the receptacle (16), valve means (25) being placed between such pumping
means (24) and the receptacle (16), such valve means (25) are connected with a recirculation
duct (26) that reconnects to the dispensing duct (14) upstream of the pumping means
(24).
9. Weight filling machine (1) according to claim 8, wherein said valve means are a pressure
limiter adjusted to the pressure (P) of the filling liquid at the float valve (17).
10. Weight filling machine (1) according to any one of claims from 1 to 9, wherein the
filling unit (2) comprises a rotating table (4) hinged on a shaft (5), wherein the
rotating table (4) comprises a plurality of plates (6) for supporting the containers
(C), a filling valve (8) being positioned above each plate (6), wherein each filling
valve (8) is connected to a distribution manifold (10), in turn connected to said
automatic refill device (15).
11. Weight filling machine (1) according to any one of claims from 1 to 9, wherein the
filling unit (2) comprises a rotating table (4) hinged on a shaft (5), wherein the
rotating table (4) comprises a plurality of pliers (7) for supporting the containers
(C) without plates, a filling valve (8) being positioned above each container (C),
wherein each filling valve (8) is connected to a distribution manifold (10), in turn
connected to said automatic refill device (15).