A tank, a tank vehicle for cleaning a sewer, and a method of emptying a tank of a tank device

Abstract

A tank, a tank vehicle for cleaning a sewer, and a method of emptying a tank of a tank vehicle, where a partition wall 16 is moved between two chambers of a tank by the use of both pneumatic and mechanical means.

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of sewer cleaning. More specific, the present invention relates a tank, a tank vehicle for cleaning a sewer, and a method of emptying a tank of a tank vehicle.BACKGROUND OF THE INVENTION

[0002] Sewer cleaning vehicles, often referred to as vacuum trucks or jetting trucks or tankers, are specialized vehicles designed to maintain and clean sewer systems, storm drains, and wastewater infrastructure, remove surface water, and for collecting the sludge and transport it to a dump site. Sewer cleaning vehicles are essential in urban environments, where proper waste management is crucial for public health, environmental protection, and the efficient functioning of municipal systems.

[0003] The sewer cleaning truck is equipped with a vacuum system, typically a vacuum pump, where the system generates strong suction capable of removing various materials, including debris, sludge, and sediments from sewer lines.

[0004] Sewer cleaning vehicles are typically further equipped with a water tank and a sludge tank for storing the removed materials.

[0005] The water tank that can typically hold several thousand liters of water which is pressurized and used to flush out sewer lines, helping to break up and remove blockages of sludge. The vehicle comprises a high-pressure water pump that ensures effective cleaning. As the water from the water tank flushes the sewer line, the sludge is sucked into the sludge tank.

[0006] The water tank and the sludge tank may be arranged as separate tanks or may, as most often is the case, be arranged in a single tank being divided into two chambers, where one chamber stores the water and the other chamber the sludge.

[0007] Between the two chambers is arranged a moveable partition wall such that the volume of the two chambers can be regulated. When the water tank is filled with water, the volume of the water tank is relatively high, and as the water is flushed out and the sludge is sucked into the sludge tank, the partition wall is moved such that the volume of the water tank is decreased and the volume of the sludge tank is increased.

[0008] When the sludge tank is full and must be emptied, the vehicle is driven to a dump site where a back hatch is opened and some sludge typically falls out. In order for completely emptying the sludge tank, the partition wall is moved such that the wall acts like a piston and pushes the sludge out of the tank.

[0009] The partition wall can move between two end positions and may be operated by two different techniques.

[0010] The first technique is where the wall is moved exclusively by air pressure, where the pressure within the water tank is raised to 0.5 bar or more, which forces the partition wall to move and press the sludge out of the sludge tank.

[0011] Being able to raise the pressure to 0.5 bar and above, which is necessary to move the partition wall, requires that the tank is specifically constructed for coping with such high pressure, that the components must be dimensioned for such high pressure, and that the wall thickness of the wall must be able to resist such pressure. A tank suitable for operating at such high pressure is thus heavy and expensive in material and production cost. The advantage of using pressurized air for moving the partition wall is that the environment inside the tank is hard on moving mechanical parts and the partition wall must be moved over a larger part of the length of the tank.

[0012] The second technique of moving the wall is exclusively by the use of mechanical means, which requires less demand on the tank itself, but requires mechanical means inside the tank, which mechanical means must be able to move the partition wall between the two end positions.

[0013] Both techniques may involve that the tank is pivoted in relation to the chassis of the vehicle, whereby the needed forces from the pneumatic means (the first technique) and the forces from the mechanical means are reduced.

[0014] Tilting the tank in relation to the chassis of the vehicle, hereby reducing the forces needed for moving the partition wall, is, when using the first technique, the known way to reduce the needed pressure and as a result reduce the requirement for the construction of the tank. However, arranging the vehicle such that the tank can be tilted incurs additional production costs and has the disadvantage that the height of the vehicle when dumping the sludge increases, which demands certain needs for the surroundings of the vehicle when dumping the content of the tank.

[0015] There is thus the need for the possibility of benefitting from the positive effect of both techniques in one solution and at the same time avoid or limit the disadvantages of each solution and avoid the known necessity of tilting the tank.

[0016] It is an object of the present invention to provide a tank for a tank vehicle, a tank vehicle, and a method of emptying a tank from sewer sludge of a tank vehicle which solves the above need.

[0017] The above object and advantages, together with numerous other objects and advantages, which will be evident from the description of the present invention, are according to a first aspect of the present invention obtained by: A tank for a tank vehicle for cleaning a sewer, the tank having a first chamber for storing sewer sludge and a second chamber for storing an amount of water separate from the sewer sludge, the tank comprising a moveable partition wall arranged between the first and second chamber and arranged moveably between two end positions for regulating the volume of each chamber, the tank comprising actuating means for moving the partition wall, the actuating means comprising pneumatic and mechanical means, both arranged for exerting an actuating force onto the partition wall.

[0018] The defined tank is construed such that it can be installed onto the chassis of a vehicle without the need for tilting the tank when dumping the sludge, and without the need for dimensioning the tank for maintaining a relatively high pressure at 0.5 bar and above.

[0019] It should be noted that though the invention throughout the description is disclosed only in relation to collecting sludge, the invention is not limited to the collection of sludge but can be used for collecting a variety of different materials, as disclosed in the introductory part of the description.

[0020] According to a further embodiment of the first aspect of the invention, the pneumatic means and the mechanical means are arranged for simultaneously exerting the actuating force onto the partition wall.

[0021] The sludge within the first chamber is quite heavy and may contain both liquid and solid material. It is thus quite demanding to move the partition wall when dumping the sludge and arranging both the pneumatic and the mechanical means for acting on the partition wall and the same time reduce the need for a "high" air pressure within the second chamber and avoid tilting of the tank.

[0022] According to a further embodiment of the first aspect of the invention, the mechanical means are arranged for exerting a force onto the partition wall over a first part of the movement between the two end positions, the first part of the movement being from a position of the partition wall where the volume of the first chamber for storing sewer sludge is larger than the volume of the chamber for storing the amount of water.

[0023] When the first chamber is filled with sludge at its maximum, the volume of the first chamber is at its maximum and the volume of the second chamber is at its minimum, as the water contained inside has been used or partly used for flushing the sewer. The mass of the sludge is thus at its maximum and the forces needed for moving the partition wall at that position are the maximum forces needed during the whole process of emptying the tank from sewer sludge. Thus, to minimize the air pressure needed for moving the partition wall out of the end position, where the first chamber is at its maximum, the mechanical means, which may be a hydraulic piston, are arranged such that they act upon the partition wall during this first movement.

[0024] The mechanical means may be arranged only for moving the partition wall over the described first part of the movement. The requirement on the mechanical means is thus reduced as they only need to move the partition wall over a part of the entire movement.

[0025] According to a further embodiment of the first aspect of the invention, the pneumatic means are arranged for exerting a force onto the partition wall during the entire movement between the two end positions, and the mechanical means are arranged for exerting a force onto the partition wall exclusively during the first part of the movement.

[0026] The mechanical means may be arranged only for moving the partition wall over the described first part of the movement. The requirement on the mechanical means is thus reduced as they only need to move the partition wall over a part of the entire movement.

[0027] According to a second aspect of the present invention, the above objects and advantages are obtained by: a tank vehicle for cleaning a sewer, the vehicle having a tank according to any of the embodiments according to the first aspect of the invention.

[0028] A tank vehicle as defined provides the possibility of a mobile solution which solves the objects of the present invention as defined above.

[0029] According to a third aspect of the present invention, the above objects and advantages are obtained by: a method of emptying a tank of a tank vehicle from sewer sludge, the tank vehicle having a tank according to any of the embodiments of the first aspect of the invention, said method comprising the following steps: activating pneumatic means, hereby applying a pneumatic pressure within the second chamber, the pressure exerting a force onto the partition wall, activating mechanical means for applying a mechanical force onto the partition wall due to a combination of the force from the pneumatic pressure and the mechanical means, moving the partition wall within the tank, such that the volume of the first chamber decreases while the volume of the second chamber increases.

[0030] According to a further embodiment of the third aspect of the invention, the force from the pneumatic pressure and the force from the mechanical means are simultaneously applied onto the partition wall.

[0031] The sludge within the first chamber is quite heavy and may contain both liquid and solid material. It is thus quite demanding to move the partition wall when dumping the sludge and arrange both the pneumatic and the mechanical means for acting on the partition wall and the same time reduce the need for a "high" air pressure within the second chamber and avoid tilting of the tank.

[0032] According to a further embodiment of the third aspect of the invention, the mechanical means are activated over a first part of said movement.

[0033] The method comprises the step of the mechanical means being activated only over a part of the movement of the partition wall, more specifically, the mechanical means are activated exclusively over a first part of the movement.

[0034] When the first chamber is filled with sludge at its maximum, the volume of the first chamber is at its maximum, and the volume of the second chamber is at its minimum as the water contained inside has been used or partly utilized for flushing the sewer. The mass of the sludge is thus at its maximum, and the forces needed for moving the partition wall at that position are the maximum forces needed during the whole process of emptying the tank from sewer sludge.

[0035] Thus, to minimize the air pressure needed for moving the partition wall out of the end position, where the first chamber is at its maximum, the mechanical means, which may be a hydraulic piston, are arranged such that they act upon the partition wall during this first movement.

[0036] According to a further embodiment of the third aspect of the invention, the mechanical means are activated exclusively over a first part of said movement.

[0037] The mechanical means are arranged only for moving the partition wall exclusively over a first part of the movement, whereby the requirement on the mechanical means is reduced as they only need to move the partition wall over a part of the entire movement.

[0038] According to a further embodiment of the third aspect of the invention, the method comprises the step of both applying said pneumatic pressure and having said mechanical means activated during the entire movement of said partition wall.

[0039] According to a further embodiment of the third aspect of the invention, the pressure within said second chamber is below 0.5 bar, such as between 0.2 - 0.5 bar.

[0040] According to a further embodiment of the third aspect of the invention, the tank is substantially horizontally positioned in relation to the vehicle during movement of the partition wall.

[0041] Fig. 1-6 show partly cross-sectional views of a tank vehicle.

[0042] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout. Like elements will thus not be described in detail with respect to the description of each figure.

[0043] Fig. 1 shows a partly cross-sectional view of a tank vehicle 10 having a tank 12 according to an embodiment of the invention. The Vehicle 10 shown is mostly build like a conventional sewer cleaner. The vehicle is not illustrated with the conventional parts, such as the hose for sucking sludge and the vacuum system for the suction, but it should be understood that the shown vehicle 10 also comprises these conventional and commonly known parts. Thus figure 1 and the remaining figures only illustrate the features necessary for understanding the invention.

[0044] The vehicle 10 comprises a chassis, upon which there is mounted a tank 12.

[0045] The tank comprises a moveable partition wall 16, which divides the total volume of the tank into two parts, a first volume being a first chamber 18, and a second volume being a second chamber 20.

[0046] The first chamber 18 is arranged for sucking in (and) storing an amount of sludge 32 by a vacuum suction system (not shown), and the second tank 20 is arranged for storing an amount of water 34, which is used for flushing the sewer.

[0047] The tank 12 further comprises a hatch 14 arranged in connection with the first chamber for storing sludge 32, such that the first chamber 18 can be emptied from sludge 32.

[0048] The tank 12 further comprises mechanical means 22, illustrated as a piston, such as a hydraulically activated piston arranged within the second chamber 20. The mechanical means 22 is arranged inside the tank 12 at the end opposite the hatch 14. The mechanical means is shown in a fully retracted configuration but is capable of being extended toward the partition wall 16 for moving the partition wall 16.

[0049] The tank 12 further comprises pneumatic means 24, 26, 28, 30 for supplying and regulating the air pressure within the tank 12. The pneumatic means comprises a compressor 24 arranged for generating the desired pressure within the first 18 and the second chamber 20. The pneumatic means further comprises a first valve connected with the first chamber 28 and a second valve 30 connected with the second chamber 20, and a conduit 26 arranged between the first 18 and second chamber 20 and the compressor 24. The vehicle further comprises a control system (not shown) for an operator to control the functioning of the parts of the tank 12. The control system is for controlling the pneumatic means and the mechanical means. The tank 12 further comprises sensors (not shown) for sensing the pressure within the first 18 and second chamber 20 and connected to the control system such that the desired, correct pressure inside the chambers can be achieved.

[0050] In the shown embodiment, the tank 12 has sucked an amount of sludge 32 and used an amount of water 34.

[0051] Fig. 2 illustrates the same tank vehicle shown in figure 1, but in an embodiment where a further amount of sludge 32 has been sucked into the first chamber 18.

[0052] The partition wall 16 is moved to one of the end positions, where the volume of the first chamber 18 is at a maximum and the volume of the second chamber is at a minimum. The first chamber 18 is filled with sludge, and the second chamber 20 has been emptied or almost emptied of water 34.

[0053] As the first chamber 18 is filled with sludge, the mass of the sludge forces the partition wall 16 toward the shown end position.

[0054] The hatch 14 has been opened and part of the sludge 32 has fallen out of the first chamber 18 and into a dump site.

[0055] Fig. 3 illustrates an embodiment where a further part of the sludge 32 has been dumped. As can be seen, the mechanical means 22 has been activated, which moves the partition wall 16 toward the open hatch, which forces the sludge 32 out of the first chamber. The movement of the partition wall 16 from the position shown in figure 2, and to the position shown in figure 3, requires the most forces used during the entire emptying process. Compared to the prior art, using exclusively air pressure to move the partition wall, the shown vehicle uses mechanical means 22 to move the partition wall.

[0056] In an alternative embodiment also encompassed within the scope of the invention, the partition wall 16 may be moved with a combination of both the mechanical means and air pressure, however, with a reduced air pressure compared with the prior art describing systems operating with air pressure at 0.5 bar or above. By operating with an air pressure below 0.5 bar, tests have shown that further dimensioning of the tank is not necessary, which limits the weight of the tank and production costs.

[0057] It should also be noted that the partition wall 16 during the shown first part of the movement may be moved entirely by the mechanical means 22.

[0058] The extent of the mechanical means 22 shown may be one example of the maximum extension of the mechanical means.

[0059] In a preferred embodiment, the mechanical means 22 acts onto the partition wall 16 only during a first part of the movement, which first part of the movement requires the most forces acting onto the partition wall 16. During the remaining part of the movement of the partition wall 16, the mass of the sludge has been reduced to such an extent that the partition wall can be removed exclusively by air pressure within the second chamber 20 and more importantly by a relative low air pressure below 0.5 bar, which reduces the structural demand of the tank, compared to the prior art.

[0060] Figure 4 illustrates the vehicle 10, where the partition wall has been moved to the other end position where all sludge has been pushed out of the first chamber. The figure illustrates the above disclosed principle of the partition wall 16 being moved the last part exclusively by the air pressure within the second chamber 20, as shown by the arrows.

[0061] Figure 5 shows the tank 12 being empty and the hatch 14 being closed.

[0062] Figure 6 illustrates the partition wall 16 being moved toward the front end of the tank 12 by use of air pressure built up by the pneumatic means 24, 26, 28 within the first chamber 18. The tank 12 is hereafter ready for filling the second chamber 20 with water 34 and starting suction of sewer sludge into the first chamber 18.

[0063] In the following is given a list of reference signs that are used in the detailed description of the invention and the drawings referred to in the detailed description of the invention. 10Tank vehicle 12Tank 14Gate 16Partition wall 18First chamber 20Second chamber 22Mechanical means 24Compressor 26Air conduit 28First valve 30Second valve 32Sludge 34Water

Claims

1. A tank (12) for a tank vehicle (10) for cleaning a sewer, said tank (12) having a first chamber (18) for storing sewer sludge and a second chamber (20) for storing an amount of water separate from said sewer sludge, said tank (12) comprising a moveable partition wall (16) arranged between said first (18) and second chamber (20) and arranged moveably between two end positions for regulating the volume of each chamber (18, 20), said tank (12) comprising actuating means for moving said partition wall (16), said actuating means comprising pneumatic (24, 26, 28, 30) and mechanical means (22), both arranged for exerting an actuating force onto said partition wall (16).

2. A tank (12) according to claim 1, said pneumatic means (24, 26, 30) and said mechanical means (22) being arranged for simultaneously exerting said actuating force onto said partition wall (16).

3. A tank (12) according to any of the previous claims, said mechanical means (22) being arranged for exerting a force onto said partition wall (16) over a first part of said movement between said two end positions, said first part of said movement being from a position of the partition wall (16) where the volume of said first chamber (18) for storing sewer sludge is larger than the volume of said second chamber (20) for storing said amount of water.

4. A tank (12) according to claim 3, said pneumatic means (24, 26, 28, 30) being arranged for exerting a force onto said partition wall (16) during the entire movement between said two end positions, and said mechanical means (22) being arranged for exerting a force onto said partition wall (16) exclusively during said first part of said movement.

5. A tank vehicle (10) for cleaning a sewer, said vehicle having a tank (12) according to any of claims 1-4.

6. A method of emptying a tank (12) of a tank vehicle from sewer sludge, the tank vehicle (10) having a tank (12) according to any of claims 1-4, said method comprising the following steps: - activating pneumatic means (24, 26, 30), hereby applying a pneumatic pressure within said second chamber (20), the pressure exerting a force onto said partition wall (16), - activating mechanical means (22) for applying a mechanical force onto said partition wall (16) due to a combination of said force from said pneumatic pressure and said mechanical means (22), - moving said partition wall (16) within said tank (12), such that said volume of said first chamber (18) decreases while said volume of said second chamber increases (20).

7. A method according to claim 6, said force from said pneumatic pressure and said force from said mechanical (22) means being simultaneously applied onto said partition wall (16).

8. A method according to claim 6 or 7, said mechanical means (22) being activated over a first part of said movement.

9. A method according to claim 8, said mechanical means (22) being activated exclusively over a first part of said movement.

10. A method according to claim 8, comprising the step of both applying said pneumatic pressure and having said mechanical means (22) activated during the entire movement of said partition wall (16).

11. A method according to any of claims 6-10, said pressure within said second chamber (20) being 0.5 bar or below, such as between 0.2 - 0.5 bar.

12. A method according to any of claims 6-11, said tank (12) being substantially horizontally positioned in relation to said vehicle during movement of said partition wall (16).

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