EP2682527B1 - Method for filling and emptying a liquid tank of a distribution device for winter service vehicles and distribution device - Google Patents

Description

The invention relates to a method for filling and a method for emptying a liquid tank of a spreading device for winter maintenance vehicles and a suitably designed for carrying out these methods spreader for winter maintenance vehicles and equipped with such a spreader winter service vehicle as such.

From the German patent application DE 10 2010 029 142 A1 is a spreader for winter maintenance vehicles known, which combines three different scattering methods, namely dry salt scattering, wet salt dispersion and pure brine scattering. Normally, the brine for the wet salt dispersion and pure brine scattering is in an additional tank, for example, the side of the scattering container in which the road salt is stored, is mounted. Since the additional tanks are too small to sprinkle a standard spreading distance of approx. 50 km with pure brine, in the DE 10 2010 029142 A1 proposed to use the scattering container either as another tank container for receiving brine. The additional tanks are retained in the event that wet salt is to be scattered and the scattering container is required to take solid Taustoffe. Instead of using the scattering container itself as another tank container, alternatively, a usable in the scattering tank tank bag can be provided. The brine required for the pure brine dispersion is conveyed from the additional tanks in a conventional manner and the additional tanks are automatically refilled from time to time with brine from the scattering tank or the tank bag received therein. The purpose of a pump, the projecting into the scattering container or tank bag hose therein absorbed brine in the additional tanks pumps. As a pump, a suction pump 51, as in FIG. 17 and 18 shown, or alternatively serve a submersible pump.

However, the use of the pumps to automatically fill the additional tanks has proven to be prone to failure.

Object of the present invention is therefore to overcome this disadvantage of the prior art.

This object is achieved by a method for filling and a method for emptying a liquid tank of a winter maintenance spreader and by a correspondingly adapted spreader with the features of the independent claims. In dependent claims advantageous developments and refinements of the invention are given.

The essence of the invention is to be seen in the fact that the automatic refilling of the additional tanks with brine from the scattering container or the tank bag inserted therein is achieved essentially solely by hydrostatic forces. By means of the solution according to the invention, it is not only possible to replenish the additional tanks during operation, but it is also possible to couple the initial filling of the additional tanks with the filling of the scattering container or the bag taken therein, that this is done in one step can. The different tank containers thus need not be filled separately, which means a significant relief and time savings.

Accordingly, the inventive method for filling a liquid tank, which includes as a first tank container such as the scattering container or the tank bag received therein and as one or more second tank container such as the aforementioned additional tanks, provides that the first tank container with the second tank or containers via a Liquid line is connected in such a way in that first the first tank container is filled with liquid, for example brine, until a moment when the liquid filled in the first tank container begins to flow through the liquid conduit into the at least one second tank container, the filling of the second container (s) Tank container with liquid from the first tank container through the liquid line therethrough following this moment.

This can in principle be done in two ways. Either one connects the liquid line in a lower region of the scattering container to this or the tank bag received therein and connects it preferably continuously downwards leading to the one or more auxiliary tanks, so that the liquid during filling of the main tank, ie the scattering container or the tank bag received therein, begins to flow directly into the additional tanks. If the height of the main tank overlaps with the height of the auxiliary tank (s) and the liquid level in the main tank rises, the liquid level in the additional tanks also rises until they are completely filled. Subsequently, the main tank can be filled up to the maximum filling volume. During the subsequent emptying of the liquid tank by removing the liquid from the additional tanks, the liquid level in the main tank first drops until it reaches the highest level of the additional tanks, whereupon the liquid level in the main and auxiliary tanks drops evenly during further emptying.

This first possibility of hydrostatic filling and emptying of the liquid tank is relatively easy to implement, if the scattering container itself is used as the first tank container, ie as the main tank. Because in this case, the liquid line can be connected in a relatively simple manner to the front sides of the main and auxiliary tanks. However, this is more problematic if, for example, a tank bag inserted in the scattering container serves as the first tank container or main tank. Because then the tank bag must be connected in a lower region of the scattering container to the Streustoffbehälterwandung or passed through them become. However, this lower region of the scattering container is difficult to access, especially if there is a tank bag therein. Since the use of a tank bag as the main tank over the use of the scattering container itself is to be preferred, offers the second possibility described below for hydrostatic filling and emptying of the liquid tank certain advantages.

According to this second possibility, the liquid line has a highest point between the two line openings at the respective ends of the liquid line. This highest point is preferably at or above an upper portion of the first tank (main tank), so that the step of filling the second tank (s) does not begin until the first tank is completely or at least almost completely filled. Namely, the filling of the second tank container (s) starts only after the liquid in the liquid line has reached the highest point, and thereafter the filling of the second tank container with liquid from the first tank container through the liquid pipe automatically proceeds by utilizing hydrostatic forces , as long as the line opening of the end of the liquid line projecting into the second tank container (auxiliary tank) is below the liquid level of the first tank container (main tank). This second possibility is not limited to the use of a tank bag as the first tank container but can also be used in consideration of certain boundary conditions which will be explained below, if e.g. the scattering container itself is used as the first tank container (main tank).

Preferably, the (first) line opening of the liquid line is close to the bottom of the first tank, so that the first tank container empties as completely as possible when emptying. For the same reason, the (second) line opening of the end of the liquid line connected to or projecting into the second tank container (auxiliary tank) is located at a position below the (first) line opening of the one connected to the first tank tank (main tank) protruding in the opposite end of the liquid line, so that the first tank container are emptied as deeply as possible when emptying the liquid tank. The (second) conduit opening is therefore preferably located below the bottom of the first tank container.

The liquid line can be guided over an upper edge of the scattering container. The highest point of the liquid line then lies above the scattering container or a tank bag received therein. On the one hand, this offers the advantage that the maximum filling volume of the first tank container (scattering container or tank bag received therein) can easily be completely filled with liquid before the filling of the second tank container through the liquid line begins. The problem, however, is that in this case when using a tank bag as the first tank container, an overpressure must be built in the tank bag to force the liquid out of the tank bag over the highest point of the liquid line out through the liquid line. It is also important that the liquid is pumped into the first tank container with such a volume flow that the liquid not only spills over the highest point but completely fills the liquid line. Because only with a closed column of liquid in the liquid line, the goal is achieved that the liquid is automatically retightened due to hydrostatic forces of the first tank into the second tank container.

If, on the other hand, the first tank container is not formed by a tank bag but, for example, by the scattering container itself, the generation of an overpressure in the first tank container is not possible. For this case, for example, a suction pump can be provided on the liquid line, with which the liquid is sucked once beyond the highest point of the liquid line out. Subsequently, the suction pump can be switched off and the further filling automatically runs off solely due to hydrostatic forces.

The overpressure problem can be avoided if the liquid line is not guided around the upper edge of the scattering container but in an upper area through the wall of the scattering container. Then, the filling of the second tank container begins when the first tank container is almost completely filled and continues automatically, as long as it is ensured that forms a closed column of liquid in the liquid line at the start of the self-filling process, as explained above.

In the upper region of the scattering container, the wall of the scattering container is relatively easily accessible even in the presence of a tank bag, so that the liquid line at this point can be easily passed through the wall of the scattering container to the tank bag or the tank bag at the appropriate location to an opening in the scattering container can be connected, at the opposite side then leading to the additional tank hose is connected.

The filling of the first tank can be stopped as soon as the second tank automatically fills due to the acting hydrostatic forces. The first tank then empties as the second tank container fills. Therefore, it is preferable to continue to fill the first tank container while the second tank container automatically fills with liquid from the first tank container until both tank containers are completely filled.

If, in later operation of the spreader, the liquid tank is emptied by branching off liquid from the second tank containers (auxiliary tanks), the liquid level in the first liquid tank (main tank, that is, scattering tank or tank bag) first drops until its liquid level reaches the level of the liquid tank highest second tank (additional tank) has dropped. Subsequently, the liquid levels in both tank containers decrease to the same extent until the (first) line opening in the first tank container protrudes above the liquid level. In this Moment rips off the liquid column in the liquid line. If the diameter of the liquid line is small and the capillary forces are sufficiently large, the liquid column located in the liquid line is retightened as the second tank container is further emptied. This effect is familiar to anyone in the context of straws. Therefore, it may be useful to form the liquid line from a bundle of lines of sufficiently small cross-section to promote this effect.

Preferably, vents are provided on the first and second tank containers, so that the air therein can escape to the extent that fills the corresponding tank container with liquid. Furthermore, a level limiter can be provided in the second tank container or in the first tank container, depending on the chosen filling principle, which sends a stop signal to the filling apparatus when a predetermined filling level has been reached.

Figur 1

ein isoliertes Streugerät gemäß einem ersten Ausführungsbeispiel in perspektivischer Ansicht,

Figuren 2 bis 9

verschiedene Zustände beim Befüllen und Entleeren des Flüssigkeitstanks des in Figur 1 dargestellten Streugeräts schematisch im Querschnitt,

Figur 10

ein Ersatzschaubild für das Streugerät gemäß Figuren 1 bis 9,

Figur 11

einen schematischen Querschnitt durch ein Streugerät gemäß einem zweiten Ausführungsbeispiel,

Figur 12

einen schematischen Querschnitt durch ein Streugerät gemäß einem dritten Ausführungsbeispiel,

Figur 13

einen schematischen Querschnitt durch ein Streugerät gemäß einem vierten Ausführungsbeispiel,

Figur 14

einen schematischen Querschnitt durch ein Streugerät gemäß einem fünften Ausführungsbeispiel,

Figur 15

einen schematischen Querschnitt durch ein Streugerät gemäß einem sechsten Ausführungsbeispiel,

Figur 16

einen schematischen Querschnitt durch ein Streugerät gemäß einem siebten Ausführungsbeispiel,

Figur 17

ein Streugerät gemäß dem Stand der Technik mit einem im Streustoffbehälter aufgenommenen Tanksack und

Figur 18

das Streugerät gemäß dem Stand der Technik aus Figur 17 ohne den Tanksack.

The invention will now be described by way of example with reference to the accompanying drawings. Show:

FIG. 1

an insulated spreader according to a first embodiment in perspective view,

FIGS. 2 to 9

different states when filling and emptying the liquid tank of the FIG. 1 shown spreader schematically in cross section,

FIG. 10

a replacement diagram for the spreader according to FIGS. 1 to 9 .

FIG. 11

a schematic cross section through a spreader according to a second embodiment,

FIG. 12

a schematic cross section through a spreader according to a third embodiment,

FIG. 13

a schematic cross section through a spreader according to a fourth embodiment,

FIG. 14

a schematic cross section through a spreader according to a fifth embodiment,

FIG. 15

a schematic cross section through a spreader according to a sixth embodiment,

FIG. 16

a schematic cross section through a spreader according to a seventh embodiment,

FIG. 17

a spreader according to the prior art with a received in the hopper tank and tank

FIG. 18

the spreader according to the prior art FIG. 17 without the tank bag.

Shown in FIG. 1 is an attachment spreader 1 as a construction on a loading area of a truck, which is not explicitly shown here. On a welded support frame 2, a scattering container 3 is constructed, which has a funnel-shaped cross-section, so that collected in the scattering container Taustoffe collect on the conically converging bottom of the scattering container 3. A screw conveyor at the bottom of the scattering container transports solid scattering substances, in particular road salt, out of the scattering container 3 to an outlet 4, through which the scattering substances in turn gravitationally in the downpipe 5 a spreader 6 and through the downpipe 5 through a scattering plate 7 of the spreader. 6 can fall. Two additional tanks 10 for liquid, in particular for a salt solution (brine), are provided in order to admix the liquid which has fallen through the downpipe 5 in a suitably metered quantity of liquid. This is done in a conventional manner via a suction line 15 using a suitably controlled pump 16. The place of admixing does not necessarily have to be in the downpipe itself, but can for example take place only at the lower end of the downpipe 5 on the spreading plate 7.

Additional tanks 10 may be provided, for example, in front of the scattering container 3. In particular, the additional tanks 10 can be made significantly smaller in size in favor of an increase in the content of the scattering container 3 than it is in FIG FIG. 1 is shown. If several additional tanks 10 are provided for mixing liquid detergents, they are preferably connected to one another via lines.

The functions pure brine spreading, dry salt scattering or wet salt scattering can be achieved with the pump 16 and suitable valves 11.2. By means of the designed as a three-way cock valve 11.2 (for example ball valve), the pump 16 can be connected to the spray 17 or the downpipe 5 to switch between the pure brine and the Feuchtsalzstreuung. If dry salt is to be scattered, that is, without admixing brine from the additional tanks 10, either the pump 16 can be switched off or the three-way cock 11.2 can be pivoted so that the line path from the pump 16 to both the spraying device 17 and the scattering device 6 is interrupted. On the other hand, it is with the in FIG. 1 illustrated position of the three-way valve 11.2 also possible to disperse both dry salt by means of the spreader 6 and pure brine by means of the spray 17. By suitable modification of the system, for example by other or additional directional control valves and / or additional lines and / or line branches and / or by one or more further pumps can also be guaranteed to sprinkle at the same time pure brine on the spray 17 and moist salt on the spreader 6.

In order now to increase the brine absorption capacity of the spreader 1, a liquid tank 40 is inserted into the scattering tank 3 and connected via a liquid line 50 to the auxiliary tanks 10. The liquid tank 40 can be filled with brine via a filler neck 42.

In addition to the filler neck 42, a feedthrough 43 is provided, through which the liquid line 50 is led into the liquid tank 20 with a hose extension 50A. The tube extension 50A extends to the bottom of the liquid tank 40. Thus, the liquid tank 40 can be completely emptied through the liquid line 50 and the additional tanks 10, that is, in the concrete embodiment according to FIG. 1 the two additional tanks 10 connecting suction line 15, are fed.

In the embodiment according to FIG. 1 For example, the liquid tank 40 is formed by a tank bag 40A which is inserted into the scattering tank 3 as described. For the purposes of the present invention, the tank bag 40A need not necessarily be made of a flexible, collapsible material, it may as well be a rigid insert tank. However, it is preferable if the tank bag, as in DE 10 2010 029 142 A1 described, is flexible and collapsible, so that it is better storable.

The tank bag 40A fills only half of the scattering container 3. In the remaining other half, a second tank bag 40A or dry spreading material can be picked up, which is then conveyed under the tank bag 40A to the spreader 6. If a second tank bag 40A is provided, an overflow between the tank bags can be provided, which is arranged as far as possible for ease of use. At the overflow of the second tank bag then in turn joins a hose extension, which extends to the bottom of the second tank bag.

Based on FIGS. 2 to 9 the principle of filling and emptying of the liquid tank is described below, which is composed here of the first tank container formed by the tank bag 40A and by two additional tanks 10 as a second tank container. The illustrations are to be understood purely schematically.

FIG. 2 shows a first phase of the filling process of the tank 40A. At this moment, the additional tanks 10 are still completely empty. The check valve 18 is closed. Instead of the check valve 18, the closing of the suction pipe 15 connected to the two auxiliary tanks 10 may also be effected solely by the pump 16 (FIG. FIG. 1 ) be ensured. According to the in FIG. 2 shown liquid level, the tank bag 40A is not completely filled. The pressure acting on the liquid corresponds to the ambient pressure p ₀ . The arrow indicates that the tank bag 40A continues to be filled with liquid through the filler neck 42.

In FIG. 3 the liquid level has risen so far that the vent valve 44 (see also FIG. 1 ) closes. A float 45 in the vent valve 44 ensures that no liquid can escape from the tank bag 40A. The pressure acting on the liquid in the tank bag 40A at this time still corresponds to the ambient pressure po. The liquid level in the liquid line 50 has already risen above the tank bag 40A.

Upon further filling of the tank bag 40A (FIG. FIG. 4 ), the pressure p acting on the liquid in the tank bag 40A is raised above the ambient pressure po. The tank bag 40A inflates (not shown), as indicated by the arrows in the tank bag, and the liquid in the tank bag 40A is forced through the liquid line 50 past the highest point 50B of the liquid line 50. This moment is in FIG. 4 shown. The one by the Filler 42 flowing volume flow is sufficiently large, so that the liquid over the highest point 50B of the liquid line 50 not only spills over, but as a closed liquid column, the liquid line 50 completely fills and flows down.

As soon as the liquid column has fallen below the lowest point of the tank bag 40A, liquid automatically flows from the tank bag 40A through the liquid line 50 into the right auxiliary tank 10 and also into the left auxiliary tank 10 via the connecting line 15. FIG. 5 illustrates this principle. The liquid level in the auxiliary tanks 10 increases in parallel as the liquid level in the tank bag 40 decreases. It is not necessary at this moment to continue to supply liquid through the filler neck 42 (however, this is advisable to keep the total filling time as short as possible).

FIG. 6 Fig. 14 shows the state in which the liquid levels in all the tank containers 40A and 10 have reached the same level. There is no further liquid flows through the liquid line 50. The liquid level of the additional tanks 10 has risen to the leading up vent pipes 30. At least now, the filling process is continued by further supply of liquid through the filler neck 42 in the tank bag 40A. The level of liquid in the vent tubes 30 continues to increase until the maximum fill volume is reached, as in FIG FIG. 7 shown. Accordingly, the vent tubes 30 end above the highest fill level of the tank bag 40A.

To empty the liquid tank, the check valve 18 is opened or the pump 16 is operated accordingly. Liquid is then withdrawn from the auxiliary tanks 10 through the suction line 15, and to the same extent, liquid from the tank bag 40A flows through the liquid line 50 into the auxiliary tanks 10, as in FIG FIG. 8 shown. The liquid level drops evenly in all tank containers 40A and 10 until it reaches the in FIG. 9 has reached the lowest level shown, in which the conduit opening of the hose extension 50A projecting into the tank bag 40A emerges from the liquid level. From this moment, the further emptying of the liquid tank takes place solely from the additional tanks 10.

Instead of the vent tubes 30, the auxiliary tanks 10 may also be equipped with vent valves 31, as in FIG FIG. 1 shown. This vent valve 31 closes similar to the vent valve 44 of the tank bag 40A automatically when a correspondingly high level is reached. This moment can be detected by measurement and serve as a signal to adjust the further filling of the tank bag 40 A, which, however, only makes sense if the filling of the tank bag 40 A is continued, while the additional tanks 10 with liquid passed through the liquid line 50 from the Fill tank bag 40A.

FIG. 10 shows an equivalent circuit diagram for the in FIG. 1 illustrated spreader. Liquid is introduced into the tank bag 40A via a filler neck 42. The tank bag 40A vented via the vent valve 44 and the liquid is supplied via the liquid line 50 and hose extension 50A of the connecting line 14 between the two additional tanks 10 through which the liquid then flows into the auxiliary tanks 10. The two auxiliary tanks 10 are connected via vent pipes 30 to a common vent 30A which ends above the auxiliary tank 40A (not shown in the replacement diagram). A separate level limiter 32 is connected to one of the two additional tanks 10 and signals at a predetermined level the end of the filling process.

Via lines 19, the additional tanks 10 are coupled to a manifold 20 which supplies the liquid from the additional tanks 10 either the scattering device 6 or another distributor 21, with which the liquid can be assigned to several spray heads 17A, 17B, 17C.

FIG. 10 represents at the same time a second embodiment as a deviation of the first embodiment, which in FIG. 11 is shown again schematically. Accordingly, here leads the liquid line 50 in a connecting line 14 between the two additional tanks 10, which is different from the manifold 20 leading to the suction lines 19, is withdrawn through the liquid from the additional tanks 10.

FIG. 12 shows as a third embodiment, a further modification, which also already in connection with the replacement diagram according to FIG. 10 was explained. Accordingly, the vent tubes 30 of the auxiliary tank 10 terminate in a common vent 30A, which in turn is a self-closing valve that closes when the liquid level in the entire liquid tank has reached the vent 30A. This can, as mentioned, be detected by measurement and serve as a signal for switching off the filling process. Accordingly, in this third embodiment, the filler neck 42 is above the vent 30A, so that the filler neck 42 can be safely closed without liquid exiting the liquid tank.

FIG. 13 shows as a further modification, a fourth embodiment. Here, the uppermost point 50B of the liquid line 50 is located in an upper portion of the tank bag 40A immediately below the maximum fill level of the tank bag 40A. The liquid therefore flows from the tank bag 40A into the liquid line 50 when the maximum level in the tank bag 40A is approximately reached without having to generate an overpressure in the tank bag 40A. The liquid line 50 then continues through in the upper region of the scattering container 3 through a wall 3A of the scattering container 3. Couplings 61 and 62 on the container wall 3A are provided to externally connect the liquid conduit 50 and internally the tube extension 50A thereto. This is also relatively unproblematic on the inside of the scattering container 3, because this point of the scattering container 3 is still easily accessible even in the presence of the tank bag 40A.

FIG. 14 shows as a further modification, a fifth embodiment in which the liquid line 50 in a lower region of the tank bag 40A, namely at the bottom of the tank bag 40A, attaches and steadily leading down to one of the two additional tanks 10 is connected. A horizontal arrangement of the liquid line 50 would be possible. Again, the couplings 61 and 62 are again provided in the wall 3A of the scattering container 3, to connect the connection to the tank bag 40A on the inside and the connection to the additional tank 10 on the outside.

FIG. 15 shows as a further modification, a sixth embodiment. In this case, the first tank container (main tank) is not formed by a tank bag used in the scattering container but by the scattering container 3 itself. A sealing plate inserted into the hopper 3 plate 28 forms the bottom of the first tank. Underneath, the conveying device for conveying solid scattering substances runs in the event that the spreading container 3 at other times does not serve as a liquid tank but in a conventional manner as a container for receiving, for example, road salt. The liquid line 50 is guided into the scattering container 3 via a passage 63 in the wall 3A of the scattering container 3 and protrudes with its hose extension 50A to the bottom of the scattering container 3. The principle of filling and emptying corresponds to the above-described principle, in particular similar to the fourth embodiment according to FIG. 13 , If the liquid pressure during filling of the tank container is not sufficient to produce a closed water column in the liquid line 50 in order to ensure an independent subsequent flow of liquid from the scattering container 3 into the additional tank 10, in addition eg a suction pump 52 and a check valve 53 be provided. First, the check valve 53 is closed and then the suction pump 52 is put into operation. Once the suction pump 52 has sucked liquid, the suction pump 52 can be turned off and then the check valve 53 are opened. Then, the liquid automatically flows through the liquid line 50 from the scattering tank 3 into the auxiliary tank 10. Others Ways to start flowing through the fluid line 50 are also possible.

FIG. 16 finally shows a seventh embodiment as a further modification. As in the sixth embodiment, here the scattering container 3 itself serves as the first tank container (main tank) for receiving the brine, and similarly as in the fifth embodiment leads here the connecting line 50 from a lower portion of the scattering container 3 steadily downward leading or alternatively horizontally in the auxiliary container 10th ,

Instead of the scattering container 3, another tank can serve as the main tank or "first tank". The principles described above, in particular the use of a connecting line 50 passing through a highest point, are equally applicable thereto.

Claims (15)

1. A method for filling a liquid tank (40A, 10; 3, 10) of a spreader (1) for winter service vehicles, wherein the liquid tank has a first tank container (40A; 3) and at least one second tank container (10) connected to the first tank container via a liquid line (50, 50A), and wherein the first tank container (40; 3) is a spreading material container (3) which is coupled or is coupleable to a spreading device (6) for spreading solid spreading materials received in the spreading material container, or a tank sack (40A) or rigid insertable tank received in the spreading material container (3), characterized by the following steps:

   - filling the first tank container (40A; 3) with liquid, such as for example brine, up to a moment as of when the liquid filled in the first tank container (40A; 3) begins to flow through the liquid line (50, 50A) into the at least one second tank container (10), and

   - filling the at least one second tank container (10) with liquid from the first tank container (40A; 3) through the liquid line (50, 50A) following the above-mentioned moment,
   or

   - filling the at least one second tank container (10) with liquid, such as for example brine, up to a moment as of when the liquid filled in the at least one second tank container (10) begins to flow through the liquid line (50, 50A) into the first tank container (40A; 3), and

   - filling the first tank container (40A; 3) with liquid from the at least one second tank container (10) through the liquid line (50, 50A) following the above-mentioned moment.
2. The method according to claim 1, wherein the liquid line (50, 50A) possesses a highest point (50B) and the step of filling the at least one second tank container (10) only begins and is continued exploiting hydrostatic forces after the liquid in the liquid line (50, 50A) has reached the highest point (50B).
3. The method according to claim 2, wherein the highest point (50B) of the liquid line (50, 50A) lies at the height of an upper region of the first tank container (40A; 3) or thereabove, so that the step of filling the at least one second tank container (10) only begins when the first tank container (40A; 3) is completely or at least almost completely filled.
4. The method according to claim 3, wherein a maximum filling volume of the first tank container (40A; 3) is completely filled with liquid before the filling of the at least one second tank container (10) begins.
5. The method according to any of claims 1 to 4, wherein the filling of the first tank container (40A; 3) is continued during the filling of the second tank container (10).
6. A method for emptying a liquid tank (40A, 10; 3, 10) of a spreader (1) for winter service vehicles, wherein the liquid tank has a first tank container (40A; 3) and at least one second tank container (10) connected to the first tank container via a liquid line (50; 50A), a first line opening of the liquid line (50A) lies in the first tank container, preferably at the bottom of the first tank container (40A; 3), and the first tank container (40A; 3) is a spreading material container (3) which is coupled or is coupleable to a spreading device for spreading solid spreading materials received in the spreading material container, or a tank sack (40A) or rigid insertable tank received in the spreading material container (3), characterized by the following steps:

   - removing liquid from the first tank container (40A; 3) through the second tank container (10) by a second line opening of the liquid line (50) being so disposed that upon removal of the liquid from the second tank container (10) liquid from the first tank container (40A; 3) flows into the second tank container (10) solely due to hydrostatic forces.
7. The method according to claim 6, wherein the liquid line (50, 50A) is so disposed that a highest point (50B) of the liquid line (50, 50A) lies between the first line opening of the liquid line (50) and the second line opening of the liquid line (50A).
8. The method according to claim 7, wherein the highest point (50B) of the liquid line (50, 50A) lies at the height of an upper region of the first tank container (40A; 3) or thereabove.
9. A spreader (1) for winter service vehicles having a liquid tank (40A, 10; 3, 10) which comprises at least one first tank container (40A; 3) and at least one second tank container (10) connected to the first tank container via a liquid line (50, 50A), wherein the first tank container (40A; 3) is a spreading material container (3) which is coupled or is coupleable to a spreading device (6) for spreading solid spreading materials received in the spreading material container, or a tank sack (40A) or rigid insertable tank received in the spreading material container (3), and wherein the liquid line (50, 50A) is attached at a first end to the first tank container (40A; 3) or protrudes thereinto and possesses there a first line opening, preferably at the bottom of the first tank container (40A; 3), and is attached at a second end to the at least second tank container (10) or protrudes thereinto and possesses there a second line opening, preferably at a place below the first line opening, wherein the liquid line (50, 50A) is arranged to transport liquid from the first tank container (40A; 3) through the liquid line (50, 50A) into the second tank container (10), or vice versa, without any device for actively conveying the liquid and solely due to hydrostatic forces.
10. The spreader according to claim 9, wherein the liquid line (50, 50A) possesses a highest point (50B) between the first line opening and the second line opening, which lies at the height of an upper region of the first tank container (40A; 3) or thereabove.
11. The spreader according to claim 9, wherein the liquid line (50, 50A) leads constantly downward or horizontally between the first line opening and the second line opening.
12. The spreader according to claim 10 or 11, wherein the liquid line (50, 50A) leads through a walling (3a) of the spreading material container (3).
13. The spreader according to any of claims 9 to 12, wherein the first tank container (40A; 3) has a first vent opening (44) which is arranged so that air can escape through the first vent opening while the first tank container (40A; 3) is being filled with liquid through an opening (42) different from the first vent opening (44).
14. The spreader according to any of claims 9 to 13, wherein the at least one second tank container (10) has at least a second vent opening (30; 30A; 31) which is arranged so that air can escape through the second vent opening while the at least one second tank container (10) is being filled with liquid through an opening different from the second vent opening (30; 30A; 31).
15. A winter service vehicle comprising a spreader according to any of claims 9 to 14.

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