NL2001432C2 - Method, filling station and storage container for providing spreading material, method for distributing spreading material and slurry-containing slurry. - Google Patents

Description

P76989NL00

Brief description: Method, filling station and storage container for the provision of spreading material, method for distributing spreading material and slurry-containing slurry

FIELD AND BACKGROUND OF THE INVENTION

The invention relates to a method, a filling station and a storage container for providing spreading material to be distributed over a road surface. The invention further relates to a method for distributing spreading material over a road surface and to a slurry containing spreading material and can be obtained with a method and / or from a filling station and / or storage container according to the invention.

Slippery roads and other pavements are preferably prevented and, to the extent that is not possible, ice, snow and / or freezing is curatively removed from the road surface as quickly as possible, whether or not after mechanical processing such as snow shovels or brushing. To this end, it is known to scatter a solid, granular material (usually NaCl), hereinafter referred to as scattering agent, from a gritter. A problem with this is that, especially with preventive spreading, the dry spreader 15 blows off the road surface through wind and passing vehicles and ends up on the roadside. To this end, it is known to moisten the salt during spreading, so that it sticks better to the road surface. A common ratio is 30% liquid (brine solution) to 70% solids. However, this requires complex devices with limited results in order to moisten the salt sufficiently intensively at a large variation of the flow rate required due to variation in required spreading width, spreading density and driving speed. Insufficient mixed solid and liquid spreader results in an unevenly distributed defrosting action and loss of spreader because it partially does not adhere well. This, in turn, results in a reduced efficiency, because additional spreading means must be applied as compensation.

2

A further problem with the spreading of grain spreader is that the grain size distribution of the spreader influences the spreader distribution. Sideways-scattered, relatively large particles on average end further sideways than sideways-scattered small particles. For an even distribution of the spreading material and to prevent spreading of spreading material in the verge, it is therefore important that the grain size distribution of the spreading material is within a narrow bandwidth. Such spreading material is, however, relatively expensive and special measures, such as the addition of anti-caking agent, are required to prevent the effective grain size distribution from changing during storage due to caking.

It is also known to dissolve the salt in water prior to being released and to spray the salt solution thus obtained over the road surface. However, this creates the problem that only a limited amount of salt can be dissolved in water, as a result of which the solution can contain relatively little salt. As a result, the thawing action of such a solution is limited, in particular if the solution is further diluted with water which, whether or not as snow or ice, is already present on the road surface or which ends up on the road surface as precipitation. A further disadvantage of the use of a salt solution as a thawing agent is that it penetrates poorly into snow and ice present and that the solution easily flows off the road surface.

In addition to combating slipperiness, the spreading of substances such as salt over a road surface can also be used for other purposes. By applying salt such as calcium chloride, for example, a hygroscopic layer, and therefore due to moisture retention, can be applied to a road surface to which fine dust adheres. This can limit the fine dust emissions from traffic.

It is known from German Auslegeschrift No. 1 188 639 and Dutch Patent No. 125 310 to add salt water to the salt prior to spreading, such that a slurry is obtained. It is further described to continuously stir the slurry thus obtained and then to apply it to the paving to be treated by means of the spreading device. This development direction has not been continued in practice. In German Auslegeschrift No. 1 279 707 it is described that there arose the problem that after scattering the remaining slurry could not be properly stored in the vehicle because it must be constantly stirred and it is proposed to solve this problem by salt and storing the water in the spreading vehicle separately and mixing it during the spreading trip.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a solution which makes it possible to distribute spreading material effectively and efficiently over a road surface by allowing an even and controllable distribution of the spreading material over the road surface to be treated in a simple manner.

According to the invention this object is achieved by providing the spreading means as laid down in claim 1 and by carrying out the control of the smoothness in a manner as laid down in claim 8. The invention can also be embodied in a filling station 20 according to claim 12 or a storage container according to claim 21 which are specially adapted for carrying out the method according to claim 1. Furthermore, the invention can be embodied in a slurry according to claim 20 which is especially suitable for being provided by the method according to claim claim 1 and from a filling station according to claim 9 or a storage holder 25 according to claim 21 and which is especially suitable for use in the method according to claim 8.

Because the spreading means is prepared and held as a slurry for delivery prior to spreading in the filling station, the grain size distribution in the slurry can be well controlled, so that a relatively homogeneous grain size distribution can be guaranteed. Submerged in liquid, undissolved granules of the spreading material appear to show relatively little tendency to clump. Moreover, a slurry (other than a slurry) can simply be agitated with some regularity, as a result of which the scattering agent is easy to handle and lumps can also be prevented easily with longer storage.

The storage container is also suitable for storing and delivering unsaturated spreader solutions, so that in particular with preventive spreading actions if only light frost is expected, the storage container can also be used for treating a road surface with only a liquid spreading solution.

A further additional advantage is that the scattering vehicles need not be arranged for initial water-mixing of the scattering means and that the scattering vehicles only need to be loaded with one substance: slurry or liquid instead of water and solid scattering means. This makes faster, safer and cleaner loading possible.

Particular embodiments of the invention are laid down in the dependent claims.

Further aspects, effects and details of the invention appear from the following description of exemplary embodiments, in which reference is made to the drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic overview of an example of a filling station according to the invention and of a distribution vehicle with a storage container according to the invention;

FIG. 2 is a top view of a mixing container of the filling station according to FIG. 1; 5

FIG. 3 is a schematic representation of a slurry according to the invention in the agitated and un-agitated state;

FIG. 4 is a schematic representation of a cut-away side view of a storage container of the filling station according to FIG. 1; and FIG. 5 is a schematic representation of a cut-away side view of the storage container of the distribution vehicle according to FIG. 1.

DETAILED DESCRIPTION

In the Figs. 1 and 2, an example of a filling station according to the invention is shown. The filling station is a station with which distribution vehicles 1 for spreading over a road surface or otherwise distributing spreading material can be filled with spreading material before driving along a spreading route and the spreading material, for example preventively or for melting already present snow and / or to spread ice on the road surface. The scattering agent can also serve to effect other properties of the road surface, such as tackiness.

The filling station according to this example is equipped with a silo 2 for storing and dispensing a spreading agent 3, such as salt or a mixture of sand and salt, in granular form. The silo 2 has a valve 4 which is movable to and fro in directions indicated by an arrow 5 for opening and closing a passage 6 in a lower end of the silo 2. The filling station can be provided with weighing means around the dispensed and still determine the quantities of water to be dispensed and the solid spreading material.

Below the opening 6 in the silo 2 there is a mixing container 7 with a mixing element 8, according to this example in the form of a mixing screw, which is coupled to a motor 9 for driving rotation of the screw 8 about its axis. In the mixer holder 7 there is also an approximately half-conical screen 10 which ensures that, if the screw 8 turns clockwise, a circulating flow through the mixer holder 7 is created, as indicated by arrows 11-14. This flow is strongest near a downstream end of the screw 8, where it is provided with grinding blades 15 to grind or break up salt lumps. Water can be introduced into the mixing container 7 via a water supply line 16 with a valve 17. After the valves 5 and 17 have been opened for suitable times, there is in the mixing container 7 an amount of spreading agent 18 and an amount of water 19 in which a part of the spreading agent may already have been dissolved. After the screw 8 has been switched on for some time, the scattering agent 18 and the water 19 are intensively and (preferably) homogeneously mixed into a slurry containing a solution of a part of the scattering agent and a part of the scattering agent 18 in solid form. Depending on the ratio between liquid and solid material in the slurry, it will be more or less liquid.

The mixing container 7 is connected via a transfer channel 20, an inlet of which is connected to a lower part of the mixing container 7, and a recirculation channel 23 to a possible storage container 21 for storing the slurry. The slurry in the storage container 21 is indicated by reference numeral 29. The recirculation channel 23 is connected to a first three-way valve 25 to which the transfer channel 20 and a discharge channel 26 connect. The recirculation channel 23 extends through a second three-way valve 27 to which a filling channel 24 also connects.

Furthermore, the filling station is equipped with a filling device for filling the distribution vehicle 1 with at least a part of the slurry 29 in the storage container 21. The distribution vehicle 1 can be wholly, for instance dependent on the amount of road surface to be treated and the required application densities, entirely or partially filled. According to this example, the filling device is formed by the filling channel 24 which can communicate via the second three-way valve 27 and a portion of the recirculation channel 23 upstream thereof with a pump 22 accommodated in the recirculation channel 23. A downstream part of the filling channel 24 extends through a filling hose 28. The discharge channel 26 connecting to the first three-way valve 25 has an inlet in a lower part of the storage holder 21. According to this example, the inlet connects to a lowest point of the storage container 21, so that all slurry 29 (apart from any slurry sticking to the walls of storage container 21) can be discharged. The storage holder 21 is provided with a vent and aeration opening for, at least excessive, over or over. prevent underpressure in the storage container 21.

Parts of the recirculation channel 23 located upstream and downstream thereof connect to the slurry pump 22. The recirculation channel 23 opens into the inner space of the storage container 21 for recirculating at least a portion of slurry 29 pumped out of the inner space by the slurry pump 22.

An aeration channel 30 opens into the outlet channel 26 and is connected to an aeration pump 31, according to this example a (centrifugal) compressor, for blowing air into the interior of the storage container 21 via the aeration channel 30 and the outlet channel 26.

If the slurry pump 22 is stationary, the slurry 29 will change to a state as shown in FIG. 1, in which the solid-state spreader 18 'present is sunk down and the liquid 19' forms a layer above the solid-state spreader 18 'and is furthermore located in interspaces between the grains of the solid part of the solid-state spreader 18'.

In order to prevent the formation of lumps, the slurry 29 is agitated periodically. Moreover, the slurry 29 can be agitated to promote the homogeneity and pumpability of the slurry 29 before and during the transfer of slurry 29 to a distribution vehicle 1.

8

The agitation is carried out according to this example by first introducing air or a gas into a lower portion of the storage container 21. Due to the rising air bubbles, a fixed part 18 'of the slurry 29 is heated up and, at least for a significant part, brought into a state floating in the solution 19'. Because the air or gas according to this example is introduced via an upstream part of the discharge channel 26, solid scattering agent that has sunk into that part of the discharge channel 26 is thereby also loosened.

According to this example, the slurry is then further agitated by recirculating it. The slurry is thereby discharged from the inner space of the storage container 21 and returned to the inner space. A portion of the slurry can optionally be permanently discharged here, for instance for filling the gritter 1.

For recirculating the slurry 29, according to this example, the pump 22 is switched on, while the first valve 25, via which the recirculation channel can be connected to either the discharge channel 26 or the transfer channel 20, is in a recirculation position. The discharge channel 26 communicates in this recirculation position via this first valve 25 with the recirculation channel 23 while the second valve 27 is in a position in which the upstream and downstream parts of the recirculation channel 23 communicate with each other. As a result, slurry 29 from the storage container 21 is pumped around via the discharge line 26 and the recirculation channel 23. This operating condition of the storage container 21 is shown in FIG. 4.

The recirculation channel 23 opens into a lower part of the inner space of the storage holder 21 (preferably lower than 25% of the height of the storage holder) which is further provided with a guide surface 32 for the horizontal movement component in the inner space of the storage holder. store slurry out of storage container 21.

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As a result, the solid fraction of the slurry 29 is effectively heated in a lower part of the inner space of the storage container 21. Moreover, a stirring effect is obtained, whereby a uniform distribution of the solid fraction of the slurry 29 within the storage container 21 is further promoted.

The guide surface could be part of an inner wall surface of the recirculation channel or of a branch of the recirculation channel. According to this example, the guide surface 32 is however designed as a distribution surface which is located downstream of the outflow opening of the recirculation channel 23 to be flowed in through a slurry flowing out of the recirculation channel 23 and which is turned towards the recirculation channel 23 for changing. of the direction of flow of the slurry flowing out of the recirculation channel 23.

It is hereby achieved in a simple manner that the direction of flow of the outflowing slurry is deflected in different directions, so that a stirring effect distributed more over the inner space of the storage container 21 is obtained.

When the three-way valves 25, 27 are adapted to allow slurry to pass from the transfer channel 20 to the recirculation channel 23 and from the portion of the recirculation channel 23 on the upstream side of the second three-way valve 27 to the portion of the recirculation channel 23 on the downstream side from the second three-way valve 27, the slurry can be pumped through the pump 22 into the recirculation channel 23 from the mixing container 7 to the storage container 21. This is preferably done while the screw 8 rotates and thereby keeps the fixed fraction of the spreading means 18 floating, at least largely, in the solution.

If the pump 22 is switched on while the first three-way valve 25 is in a position in which the discharge channel 26 communicates with the recirculation channel 23 and in which the second valve 27 in the recirculation channel 23 is in a position in which the upstream portion of the Recirculation channel 23 communicates with the filling channel 24, slurry is pumped from the storage container 21 to the vehicle 1. The second valve 27 in the recirculation channel 23 can also be brought into a position in which the upstream portion of the recirculation channel 23 communicates both with the downstream portion of the recirculation channel 23 and with the filling channel. In that case, a portion of the slurry pumped through the pump 21 to the valve 27 is fed to the vehicle 1 and another portion of the slurry pumped through the pump 21 to the valve 27 is recycled to the interior of the storage container 21.

By storing the spreading material as a component of a slurry 15, it appears that a uniform grain size distribution of the part of the spreading material that is in solid form can be reliably maintained. Moreover, the slurry present in a premixed form can be quickly transferred from a filling station. Because the processing of substantially dry spreader and water into a slurry is carried out in a filling station, the distribution vehicle does not have to be adapted for mixing spreader and water into a slurry (such as separate storage containers and dosing means for water and spreader), but it is sufficient if provisions are present in the distribution vehicle for the slurry to be sufficiently mixed again in order to effect a uniform distribution of the solid fraction of the spreading means.

Because the grinding members 15 are located in the mixing container 7, grinding of the spreading agent is carried out during the mixing, wherein large parts are reduced to finer parts, in the water and caking after grinding is effectively prevented. This effect can also be achieved if the milling arrangements are arranged such that the milled grinding agent is introduced into the water immediately after milling.

For filling the distribution vehicle with a slurry with a constant composition, it is furthermore advantageous if the slurry is filled to the distribution vehicle 1 while the slurry is agitated in the storage container 21.

In order to prevent clumping, it is furthermore advantageous that the storage holder 21 is provided with provisions for agitating the stored slurry. Because the stored slurry is agitated at least periodically, clumping is prevented further. According to the example shown, this is performed by the above-described pumping of slurry.

That the provisions for agitating the stored slurry 15 include a pump 22, conduits 23, 24, 26 and valves 25, 27 which are adapted to circulate slurry from the storage container 21 in an agitation position and to pump it into a filling position from slurry from the storage container 21 to the distribution vehicle 1 is advantageous here, because the pump 22 can be used both for supplying, discharging and for agitating slurry.

A further increase in efficiency has been achieved at the filling station according to this example, because the pump 22, the pipes 20, 23, 24, 26 and the valves 23, 25, 29 are arranged such that the pump 22 is also suitable for pumping slurry can be used from the mixing holder 7 to the storage holder 21.

To transfer slurry from the distribution vehicle 1 to the storage container 21, a branch of a dispensing channel of the distribution vehicle can be connected to the recirculation line 23. This makes it possible to transfer slurry remaining after the slurry has been scattered from the distribution vehicle 1 from the distribution vehicle 1 to the 12 storage container 21 of the filling station. Optionally, the slurry container can be flushed from the distribution vehicle, so that no solid spreading material remains there which can caked up during prolonged storage.

Within the scope of the invention, it is also possible to transfer the slurry 5 directly from a mixing container such as the mixing container 7 to a vehicle. Because a separate buffer holder 21 is provided, a large amount of slurry can be loaded into distribution vehicles in a short time. This is of particular importance in the case of sudden smoothness.

The filling station is further equipped with a water supply line 34 with a valve 35 and a flow meter 36 therein. In the filling channel 26, a flow meter 37 is also included. The flow meters 36, 37 are coupled to the valve 35 for controlling the flow through the valve 35. If it is desired to fill the distribution vehicle 1 with a slurry with a water / solid ratio with a larger water content than the water content of If the slurry in the storage container 21, the valve 35 can be opened in a dosed manner to mix in dosed water during the filling of the distribution vehicle 1.

In order to be able to keep the slurry in the storage container 21 and in the distribution vehicle 1 for a long time in a good condition and to be able to prevent the spreading agent in particular in a simple manner, it is advantageous if the volume percentage of solid matter in the slurry is less than about 70%, or at least is such that a layer of liquid stands above the spreading material in solid matter. For easily agitating the slurry, it is furthermore advantageous if the volume percentage of solids in the slurry is less than 70%, for example less than 30, 50 or 60%. In this context, the solid is understood to mean the part of the spreading material present in the slurry in solid form.

An example of such a slurry is shown schematically in FIG. 3, wherein on the left side a slurry 29 is shown in an agitated state and on the right side a slurry 29 is shown in an agitated state. The amount of water in the slurry is so large that if it is not agitated for some time, a layer of liquid 19 'consisting of water and dispersing agent dissolved therein will be placed above a layer 18' of settled solid particles. The volume of this layer of liquid above the layer of settled particles is, after a service life sufficient for the solid particles to settle and / or float up, is preferably approximately 30% of the volume of the layer of settled particles including the volume of the liquid between the settled particles of the layer (the complement to the aforementioned solids volume percentage of 70%). The amounts of water described above are important for leaving sufficient space between the floating particles in the agitated state. As a result, the solid particles in the slurry can relatively easily be brought into a fluidized state, in which state the slurry is moreover sufficiently thin-fluid to be able to be pumped and scattered easily. The slurry therefore preferably also has a composition as described above during the spreading of the slurry.

Within the scope of the invention as laid down in the claims, various other embodiments than the embodiments described above by way of example are possible. For example, instead of from a silo 2, the spreading means can also be brought from a supply into a mixing container in a different manner, such as by means of a shovel, and the milling members can be located in a milling station upstream of the mixing container. Furthermore, the solid particles in the slurry may also contain insoluble particles such as sand. Instead of or in addition to Sodium salt, other salts, such as Calcium and

Magnesium salts and / or thawing agents such as sugars or alcohols are incorporated in the slurry.

In FIG. 5 is a storage holder 51 of the distribution vehicle 1 according to FIG. 1 shown in more detail. The storage holder 51 is composed of four storage holder sections 51-1, 51-2, 51-3 and 51-4. Depending on the desired capacity and size of the storage container sections, the storage container can be composed of more or fewer storage container sections.

The storage container sections 51-1, 51-2, 51-3 and 51 * 4 and the channels for filling, agitating, recirculating and dispensing slurry are designed in a similar manner as the holder 21 and the associated channels 20, 23, 24 , 26 for filling, agitating, recirculating, and releasing slurry.

A transfer channel 50 with a connecting coupling 70 to which the filling hose 28 (see Fig. 1) can be connected is coupled via a first three-way valve 55 to a recirculation channel 53 and to, downstream of valves 68-1, 68-2, 68-3 and Located at 68-4, recirculation channel branches 53-1, 53-2, 53-3 and 53-4 to the storage container sections 51-1, 51-2, 51-3 and 51-4. A discharge channel 56 also connects to the first three-way valve 55. Drain branches 56-1, 56-2, 56-3 and 56-4 located upstream of valves 69-1, 69-15 2, 69-3, and 69-4 are connected to the discharge channel 56. The recirculation channel 53 extends through a slurry pump 52 and a second three-way valve 57 to which also a delivery channel 54 connects. In the delivery channel 54, a flow meter 69 and a control valve 71 for controlling the dosing of the delivery of slurry are included. The dosage is preferably adjustable as a density distribution per unit of road surface area, wherein the control valve 71 is controlled in dependence on the set density, the flow rate measured by the flow meter 69 and the current travel speed. The dispensing channel 54 opens out above a distribution disc 72 which is rotatable about an axis 73 for distributing the slurry also in a transverse direction over a desired discharge width.

The branches 56-1, 56-2, 56-3, 56-4 of the discharge channel 56 connecting to the first three-way valve 55 each have an inlet in a lower part of one of the storage holder sections 51-1, 51-2, 51- 30 3 and 51-4. According to this example, the inlets also connect to lower parts of the storage container sections 51-1, 51-2, 51-3 and 51-4, so that the slurry, apart from any slurry sticking to the walls of the storage container 51, can be discharged .

Parts of the recirculation channel 53 located upstream and downstream 5 thereof connect to the slurry pump 52. The branches 53-1, 53, -2, 53-3 and 53-4 of the recirculation channel 53 each open into the inner space of one of the storage holder sections 51-1, 51-2, 51-3 and 51-4 for the recirculating at least a portion of slurry pumped through the slurry pump 52 from the inner space of the relevant storage container portion 51-1, 51-2, 51-3 and 51-4.

To aeration channel 60 are connected downstream of valves 62-1, 62-2, 62-3, 62-4 aeration channel branches 60-1, 60-2, 60-3 and 60-4, each of which flows into one of the branches 56-1, 56-2, 56-3 and 56-4 of the discharge channel 56 and, at least when the relevant valves 62-1, 62-2, 62-3, 62-4 are open, communicate with an aeration pump 61 , according to this example a centrifugal compressor, for injecting air into the interior of the storage container sections 51-1, 51- via the aeration channel 60 and the branches 56-1, 56-2, 56-3 and 56-4 of the discharge channel 56 2, 51-3 and 51-4. Moreover, a branch 60.5 of the aeration channel 60 connects downstream of the slurry pump 52 and the second three-way valve 57 to the recirculation channel 53.

In addition, a top outlet channel 74 with branches 74-1, 74-2, 74-3 and 74-4 upstream of valves 78-1, 78-2, 78-3 and 78-4 respectively connects to the discharge channel 56. 78-4. The branches 73-1, 73-2, 73-3, 73-4 each have an upstream end which is designed as a flexible, helically extending hose 76 with an inlet end coupled to a float 75 for taking up liquid on the surface of which the float 75 floats.

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The slurry pump 52, the aeration pump 61 and all valves 55, 57, 56-1, 56-2, 56-3, 56-4, 62-1, 62-2, 62-3, 62-4, 68-1 shown , 68-2, 68-3, 68-4, 69-1, 69-2, 69-3, 69-4, 78-1, 78-2, 78-3, 78-4 are coupled to a controller 77 for controlling the pump 52 and the compressor 61 as well as the positions of the valves.

For filling the storage holder 51, the first three-way valve 55 is brought into a position in which the filling channel 50 communicates with the recirculation channel 53 and the second three-way valve 57 is brought into a position in which the portions of the recirculation channel 53 communicate upstream and downstream thereof with each other and the delivery channel 54 is closed. Moreover, one or more of the valves 68-1, 68-2, 68-3, 68-4 is introduced into the recirculation channel 53 in a position for passing slurry to the branch 53-1, 53-2, 53 connected thereto. -3, 53-4. The pump 52 can thereby be activated or allowed to run freely if the pressure for displacing the slurry supplied by the pump 22 of the filling station (see Fig. 1) is sufficient. By successively opening the valves 68-1, 68-2, 68-3, 68-4 or successively closing them from a state in which they are all open when the respective compartments are full, the storage container 51 can be filled to all compartments are full. It is also possible to only completely or partially fill one or more of the compartments if the amount of slurry to be dispensed is smaller than the capacity of the storage container 51.

By activating the aeration pump 61 and alternately preferably only operating one or more of the valves 62-1, 62-2, 62-3, 62-4 for selectively in connection with one or more of the aeration branches 60- 1, 60-2, 60-3 and 60-4 of the aeration pump 61, the slurry contained in the storage container 51 of the distribution vehicle 1 can in each case only be supplied in one resp. a plurality of the 30 compartments formed by the storage holder sections 51-1, 51-2, 51-3, 51-4 are agitated. This makes it possible to perform the agitation with a relatively low power.

In addition to the aeration branches 60-1, 60-2, 60-3 and 60-4 of the aeration channel 60, the blowing in of air can also be carried out via the recirculation channel 53. The air to be blown in is thereby transferred to one or more interior spaces of the storage container sections 51-1, 51-2, 51-3, 51-4 passed through the branching channel 60-5 of the aeration channel 60 and via one or more of the valves 68-1, 68-2, 68-3, 68- 4 to which a branch 53-1, 53-2, 53-3, 53-4 of the recirculation channel 53 connects. By selectively selecting one or more of the corresponding valves 62-1, 62-2, 62-3, 62-4, 68-1, 68-2, 68-3, 68-4 in the aeration channel 60 and in the recirculation channel 53 opening for the passage of air to the respective branches 53-1, 53-2, 53-3, 53-4, 60-1, 60-2, 60-3 and 60-4, the blowing in of air can be simultaneously carried out via the aeration channel 60 and via the recirculation channel 53. However, it is also possible to perform the blowing in of air only via the aeration channel 60 or via the recirculation channel 53 or to blow air into the one compartment via the aeration channel 60 while air is blown into another compartment via the recirculation channel 53.

For effective uplift of solid particles in lower portions of the compartments of the storage holder 51, and in particular in the branches 56-1, 56-2, 56-3, 56-4 of the discharge channel 56, it is advantageous in each case first of all to blow in air through the aeration channel 60, because it allows air to be blown into the branches 56-1, 56-2, 56-3, 56-4 of the discharge channel 56 at high pressure. Thereafter, for further homogenization of the slurry, air blowing in via the recirculation channel 53 is switched on.

To prevent deposits of solids in the channels after stopping of spreading without a compartment 30 being completely emptied or after recirculation, it is also possible after recirculation 18 or recirculation to circulate briefly in a recirculation sentence wherein liquid is withdrawn from the top region of a compartment and is returned to the relevant compartment via the discharge channel 56 and the relevant branch 56-1, 56-2, 56-3, 56-4 thereof. In this way it is achieved that solids are flushed out of the channels before the liquid in the channels comes to a standstill. This technique can of course also be applied to a storage container that is not divided into compartments. In that case, in the opposite sense of recirculation, the interior of that storage container recirculates. For the service life of the aforementioned facilities, it may also be beneficial to rinse with clean water after use.

For further homogenization of the slurry, slurry can then be recirculated by pumping it off the discharge channel 56 via the relevant branches 56-1, 56-2, 56-3, 56-4 and, at least partially, to the relevant compartment of the storage container 51, by placing the first and second three-way valves 55 and 57 in positions for flowing the slurry to and through the recirculation channel 53 and through the respective one of the valves 68-1, 68-2, 68-3, 68-4 in the recirculation channel 53. The blowing in of air 20 can thereby be stopped or, whether or not with reduced power, be continued. The latter is advantageous to prevent clogging of the discharge channel 56 with slurries having a relatively small liquid content. Because recirculation can also be carried out for a compartment at a time, a relatively low power is also sufficient for this.

Thus, to prevent clumping as well as to bring the slurry into a homogeneous state for delivery, both the blowing in of air and the recirculation of slurry can be carried out as a compartment. It is also possible to pump slurry from one compartment to the other.

19

In preparation for distributing slurry on a road surface while the vehicle is being driven, the slurry is heated in one of the compartments by blowing in air as described above. Subsequently, slurry is recirculated from that compartment, also as described above. A state is thus achieved in which slurry is present in an agitated, relatively homogeneous state in the relevant compartment, the discharge channel 56 and the recirculation channel 53 and is pumped around by the pump 52. By subsequently bringing the second three-way valve 57 into a position in which at least a portion of the slurry reaching the second three-way valve 57 is pushed into the delivery channel 54, a slurry flow to the spreader 72 which is held in rotation about the axis 73 and the slurry spread in the width direction of the road surface. Because the grain size of the solid particles in the slurry is within a relatively narrow range, the distribution of the slurry over the road surface can be well controlled. Moreover, the slurry adheres better to the road surface than road salt moistened during spreading, while on the other hand it does not contain so much liquid that an important amount of the slurry flows from the road surface.

If the application of a low density defrosting agent is desired, for example because a road surface is only treated additionally and / or because the road surface is preventively treated in anticipation of light frost and little precipitation and / or freezing, it may be advantageous to use only liquid containing therein. distribute dissolved thawing agent on the road surface. This can be done with the storage holder 51 according to this example, by adjusting the valves 69-1, 69-2, 69-3, 69-4 in the discharge channel 56, the first three-way valve 55 and the second three-way valve 57 to to allow top discharge channel 74 to communicate with dispensing channel 54, to close valves 68-1, 68-2, 68-3, 68-4 in recirculation channel 53 so that no liquid is recycled. By opening one or more of the valves 78-1, 78-2, 78-3, 78-4 in the upper discharge channel 74, it can then be effected that the pump 52, when it is switched on, via a hose 76 in the respective compartment feeds liquid from the surface of the un-agitated slurry that is in a state with liquid 19 'above the solid-state components 18', as in FIG. 4 on the 5 left is shown. The float 75 drops as the liquid surface drops, until the solid particles are reached or, if they are not present in the compartment, until the bottom of the compartment is reached. A special advantage of the use of inlet openings coupled to floats is that liquid can be dispensed while soluble slurry components are present in the storage container in solid form, without being drained away. This in turn makes it possible, as long as sufficient soluble slurry constituents are present in the storage container in solid form, to refill the storage container 51 with water only and subsequently to obtain a solution and a slurry with thawing agent.

Many other embodiments are possible within the framework of the invention than the embodiments discussed above by way of example. For example, the valves for selectively closing the various branches can be designed as valves in the branches instead of, as in the example shown, as three-way valves to which the branches connect. The various channels can be designed as passages through conduits, but can also be wholly or partially formed by passages through other bodies, such as fittings and valve housings. The interior spaces of the storage container sections can instead of being designed as compartments of a storage container also be designed as interior spaces of a plurality of individual storage containers.

For the purpose of loosening settled spreading material in solid form, a stirrer 30 may be used instead of or in addition to an aerator. The drive of the stirrer is then preferably controlled 21 in such a way that, when stirring is started, the stirrer is initially moved slowly and then moved faster. Moreover, if different transmissions are used for this purpose in the stirrer drive, a relatively large force is available when starting the stirrer to release any adhering spreader in solid form.

The grinding of the spreading agent in solid form, so that excessively large grains and lumps are reduced, can optionally also be achieved without using separate grinding provisions. For example, when pumping slurry around, depending on the pump type used for that purpose, in many cases all the effect is obtained that in particular larger particles in the slurry are reduced.

Claims (25)

Method for providing spreading material (3) to be distributed over a road surface, comprising: mixing water and spreading material (3) at a stationary filling station into a slurry (29) containing a solution (19, 19 ') of 5 a part of the spreading means (3) and a part (18, 18 ') of the spreading means (3) in solid form; and transferring at least a portion of the slurry (29) from the filling station to a distribution vehicle (1). The method of claim 1, further comprising grinding the spreading means (3) immediately prior to or during mixing. Method according to claim 1 or 2, wherein the stored slurry (29, 29) is agitated periodically. 15 Method according to one of the preceding claims, wherein the filling of the distribution vehicle (1) with the slurry (29) takes place from a supply of the slurry (29) while it is agitated. A method according to any one of the preceding claims, wherein agitating the slurry (29) and filling the distribution vehicle (1) takes place by means of the same pump (22). 6. Method as claimed in any of the foregoing claims, further comprising scattering the slurry (29) from the distribution vehicle (1) and transferring excess slurry (29) from the distribution vehicle (1) to the filling station or to a filling station after scattering another filling station. A method according to any one of the preceding claims, wherein the volume percentage of solid (18, 18 ') in the slurry (29) is less than 70%. A method for distributing spreading material over a road surface, comprising spreading from a moving distribution vehicle (1) a slurry (29) containing a liquid, a first part of a spreading material (3) dissolved in the liquid and a further part ( 18, 18 ') of the spreading agent (3) in solid form. 10 A method according to claim 8, wherein the slurry is located in compartments (51-1, 51-2, 51-3, 51-4) of a storage container (51) of the distribution vehicle (1) and wherein the slurry is in each case exclusively a subset of said compartments (51-1, 51-2, 51-3, 51-4) is agitated. The method of claim 3 or 9, wherein agitating comprises introducing air or gas into a lower portion of the storage container (21; 51). 20 The method of claim 10, wherein the air or gas is introduced into a discharge channel (26; 56) adjacent to a lower portion of the storage container (21; 51) and then slurry is recirculated through it via the discharge channel (26; 56) ) and return, at least in part, to the storage container (21; 51). 12. Filling station for providing spreading material (3) to be distributed over a road surface, comprising: a mixing container (7) with a mixing member (8) for mixing water and spreading material (3) into a slurry (29) containing a liquid (19 ') containing a portion of the scattering agent (3) dissolved in the liquid as well as a portion (18', 19 ') of the scattering agent (3) in solid form; and a filling device (22, 23, 24, 26, 27, 28) for transferring at least a portion of the slurry (29) to a distribution vehicle (1). 5 The filling station of claim 12, further comprising a storage container (21) and a transfer channel (20) for transferring slurry (29) from the mixing container (7) to the storage container (21), the filling device (22, 23, 24 , 26, 27, 28) is adapted to transfer slurry (29) from the storage holder (21) to the distribution vehicle (1). A filling station according to claim 12, wherein the filling device is adapted to transfer slurry (29) directly from the mixing container to the distribution vehicle. 15 A filling station according to any one of claims 12-14, further comprising a grinding member (15) upstream of or in the mixing container (7). 16. Filling station according to any of claims 12-15, further comprising a storage holder (21) equipped with provisions (22, 23, 25, 26, 27, 30, 31, 32) for agitating the stored slurry (29). 17. Filling station according to claim 16, wherein the provisions for agitating the stored slurry (29) comprise a pump (22), pipes (23, 26) and valves (25, 27) which are adapted for recirculating in an agitation position pumping slurry (29) out of the storage container (21) and pumping slurry (29) from the storage container (21) to the distribution vehicle (1) in a filling position. Filling station according to claim 17, wherein the pump (22), at least a part of the pipes (23, 26) and the valves (25, 27) are also adapted to transfer slurry (29) from the mixing container in a transfer position (7) to the storage container (22). 5 A filling station according to any one of claims 12-18, wherein the storage container (21) is provided with a connection for transferring slurry (29) from the distribution vehicle (1) to the storage container (21). A slurry containing a saturated solution (19, 19 ') of water and a portion of a scattering agent (3) and a portion (18, 18') dissolved therein in solid form, the volume percentage of substance in solid form in the slurry (29) is less than 70%. A storage container with an inner space for storing therein a slurry (29) containing a solution (19, 19 ') of a portion of a spreading means (3) and a portion (18, 18') of the spreading means (3) in solid form, which storage container is provided with: a drain (26; 56, 56-1, 56-2, 56-3, 56-4) having an inlet in a lower region of the storage container (21; 51); an aeration channel (30; 60, 60-1, 60-2, 60-3, 60-4) terminating in the discharge channel (26; 56); a slurry pump (22; 52) for pumping slurry through the discharge channel (26; 56, 56-1, 56-2, 56-3, 56-4) in a direction away from said inlet; and an aeration pump (31; 61) connected for blowing air or gas into said air via the aeration channel (30; 60, 60-1, 60-2, 60-3, 60-4) and the discharge channel (26; 56) interior space. The storage container of claim 21, further comprising: at least two storage container portions (51-1, 51-2, 51-3, 51-4) each having one of said interior spaces, which interior spaces are at least partially separated from each other; at least two outlets (56-1, 56-2, 56-3, 56-4), each with an inlet in a lower region of one of said interior spaces; and at least two aeration channels (60-1, 60-2, 60-3, 60-4), each culminating in the at least one discharge channel (60); wherein at least: the slurry pump (22; 52) for pumping slurry through the discharge channels (56-1, 56-2, 56-3, 56-4) through a valve structure (69-1, 69-2, 69) -3, 69-4) is connected for selectively connecting the slurry pump (52) to one of the discharge channels (56-1, 56-2, 56-3, 56-4); or wherein the aeration pump (61) is connected via a valve structure (62-1, 62-2, 62-3, 62-4) for selectively in connection with one of the aeration channels (60-1, 60-2, 60 -3, 60-4) bringing the aeration pump (60). The storage container of claim 21 or 22, further comprising a recirculation conduit (23; 53) connected to said slurry pump (22; 52) and terminating in said interior for recirculating at least a portion of said slurry pump (22; 52) said interior space pumped slurry. The storage container of claim 23, wherein the recirculation channel 25 (23; 53) opens into a lower portion of said interior space, further comprising a guide surface (32) for inserting a horizontal movement component into the interior space of the storage container (21; 51) outflow of slurry. 25. Storage container according to claim 24, wherein the guide surface (32) is designed as a distribution surface which is located downstream of an outflow opening of the recirculation channel (23; 53) for being inflowed by a recirculation channel (23; 53) in a flow direction flowing slurry and toward the recirculation channel (23; 53) for changing the direction of flow of the slurry flowing out of the recirculation channel (23; 53).