WO2007143994A1

WO2007143994A1 - Slurry tanker with ejector and method for filling a tank on the slurry tanker

Info

Publication number: WO2007143994A1
Application number: PCT/DK2007/000283
Authority: WO
Inventors: Morten ALLERØD
Original assignee: Samson Agro A/S
Priority date: 2006-06-15
Filing date: 2007-06-12
Publication date: 2007-12-21

Abstract

There is disclosed a slurry tanker with a tank (1) having an feed line (48) with a filling pump (13) for filling with slurry for pumping the slurry from a container (16) to the tank, and a discharge line (49) with an emptying pump (2) for pumping slurry out of the tank (1). The lines are provided with valves for optional shutting off/connecting between the pumps and the tank, in order to fill the pump (13) with slurry without the need of lowering into the slurry container (16), a return line (50) to the tank is provided in connection with the emptying pump (2). In this return line (50), an ejector (6) is disposed and connected to a pressure source for a medium for establishing ejector action. The ejector has a suction line (51) which via a shut-off valve (9) can be connected to the filling pump (13) for aspirating the slurry through the filling pump.

Description

Slurry Tanker with Ejector and Method for Filling a Tank on the Slurry Tanker

Field of the Invention

The present invention concerns a slurry tanker with a tank having an feed line with a filling pump for filling with slurry for pumping the slurry to the tank, and a discharge line with an emptying pump for pumping slurry out of the tank, which lines being provided with valves for optional shutting off/connecting between the pumps and the tank.

The invention furthermore concerns a method for filling a slurry tanker with a tank having an feed line with a filling pump for filling with slurry for pumping the slurry to the tank, and a discharge line with an emptying pump for pumping slurry out of the tank, which lines being provided with valves for optional shutting off/connecting between the pumps and the tank.

Background of the Invention

In slurry tankers of the mentioned type, a filling pump which is not self-priming will usually be applied. This filling pump is used for filling the tank while submerged into a tank on a farm or similar, whereafter it pumps the slurry over into the tank.

It is also known with a slurry tanker in which is used a self-priming pump (figure- eight-pump) which is very expensive and sensitive. This self-priming pump is placed where a crane is built on the tank, i.e. it cannot be lowered into the slurry and attain the best filling capacity.

Object of the Invention

It is the purpose of the present invention to indicate a slurry tanker that enables the possibility of filling a slurry tanker in a technically simple and cheap way by means of a non-self-priming pump, even if this pump cannot be submerged into the slurry to be pumped over into the tank. Description of the Invention

According to the present invention, this is achieved with a slurry tanker of the type specified in the introduction, which is peculiar in that a return line to the tank is provided in connection with the emptying pump, that in this return line an ejector is disposed and connected with a pressure source for a medium for establishing an ejector action and which has a suction line which via a shut-off valve may be connected with the filling pump for aspirating the slurry through the filling pump.

The method according to the method is peculiar in that there is provided an ejector action in a return line connecting the emptying pump with the tank, and that this ejector action is used for establishing a vacuum which is connected to the pressure side of the filling pump in order to aspirate slurry through the filling pump.

By such a system, it is possible to fill a slurry tanker by means of a non-self-priming pump, even if this pump cannot be submerged in the slurry to be pumped into the tank. The pump may thus be filled with slurry without needing to lower into the slurry tanker.

hi order to fill the pump with slurry without the need of lowering into the slurry container, a return line to the tank is provided in connection with the emptying pump, hi this return line, an ejector is disposed and connected to a pressure source for a medium for establishing ejector action. The ejector has a suction line which via a shut- off valve can be connected to the filling pump for aspirating the slurry through the filling pump.

The ejector/ejector action provides for filling the pump, after which it may be used for filling the tank in the usual way. The medium used for establishing the ejector action may either be a residual amount of slurry in the tank or pressurised air from a compressor.

According to an embodiment of the present invention, the slurry tankers are peculiar in that the pressure source is provided by the pressure side of the emptying pump. Hereby is applied a liquid driven ejector. According to a further embodiment of the present invention, the slurry tankers are peculiar in that the pressure source is provided by an air compressor. Hereby is used an air-powered ejector which preferably will be driven by the air compressor on a tractor used for towing the slurry tanker.

According to a further embodiment of the present invention, the slurry tankers are peculiar in that the pressure source furthermore includes an air bottle. Hereby is more easily attained a sufficient vacuum in an air-powered ejector.

As filling pump and emptying pump are commonly used centrifugal pumps which are reliable, simple and cheap pumps.

In order that this design will work there is only required a small residual amount of slurry in the tank. When the tank is to be filled, the feed line is lowered into the slurry located in a farm tank or similar container, and which is to be transferred to the tank, hi this situation, a section of the line extending past the filling pump will be lowered into the slurry and the filling pump will be situated at a position above the slurry.

The valves are set so that the emptying line is connected with the return line so that the emptying pump can pump the slurry present in the tank through the ejector and back into the tank when the emptying pump is activated. Furthermore, the valves are set so that the suction line of the ejector is connected to the pressure side of the filling pump. Due to the ejector action, the slurry from the farm tank or similar container will be sucked through the filling pump. When the filling pump is filled with slurry, it may be activated so that it is used in a traditional way to fill the tank of the slurry tanker as it sucks the slurry up from the farm tank and pumps it over into the tank of the slurry tanker. During the aspiration, a shut-off valve between the filling pump and the tank will be closed, and this shut-off valve is opened simultaneously with activation of the filling pump so that the slurry is pumped into the tank. At the time where the filling pump is activated, one may optionally reset the valves and switch off the emptying pump in order thereby to stop the ejector action, as the filling pump usually may fill the tank without difficulty.

hi some situations, it may, however, be advantageous to let the emptying pump continue its activity, as the ejector action can be used for supporting and enhancing the filling of the tank. This may particularly be an advantage by pumping heavy slurry. The heavy slurry can make the filling pump cavitate due to air pockets.

The emptying pump is not stopped when partially or completely opening the shut-off valve connecting the filling pump with the tank. You are ready all the time to close the shut-off valve when the filling pump cavitates. Then filling with ejector is continued until the vacuum again drops to a predetermined level, and the valve may again be opened completely or partially.

A solution with ejector according to the present invention costs 4 - 5 times less than the described design with self-priming pump.

The invention furthermore concerns a method for filling a slurry tanker with a tank having an feed line with a filling pump for submerging into slurry for pumping the slurry to the tank, and a discharge line with an emptying pump for pumping slurry out of the tank, the lines being provided with valves for optional shutting off/connecting between the pumps and the tank. This method is characterised in that there is provided an ejector action in a return line connecting the emptying pump with the tank, and that this ejector action is used for establishing a vacuum which is connected to the pressure side of the filling pump in order to aspirate slurry through the filling pump.

As alternative to a liquid ejector, an air ejector may be used. This type of ejector will be particularly suited in connection with slurry tankers with air brakes. That means in applications where a tractor used for towing the slurry tanker has an air compressor which may fill an air bottle of appropriate size to produce the required vacuum in the ejector. Description of the Drawing

The invention will then be explained in more detail with reference to the accompanying drawing, where:

Fig. 1 shows a schematic drawing of a slurry tanker according to the present invention; Fig. 2 shows a side view of an ejector for use in a slurry tanker according to the invention;

Fig. 3 is an end view of the ejector shown in Fig. 3; Fig. 4 shows a view of a partly transparent ejector of the ejector shown in Fig. 2;

Fig. 5 shows a view of a slurry tanker according to the invention in a situation of use;

Fig. 6 shows a view corresponding to Fig. 5 of a further embodiment of a slurry tanker according to the present invention in a system interacting with the docking station;

Fig. 7 shows a schematic drawing corresponding to Fig. 1 of the slurry tanker shown in Fig. 6;

Fig. 8 shows a view corresponding to Fig. 5 of yet a further embodiment of a slurry tanker according to the present invention in a system interacting with the docking station;

Fig. 9 shows a schematic drawing corresponding to Fig. 1 of the slurry tanker shown in Fig. 8; Fig. 10 shows an schematic drawing corresponding to Fig. 1 of a further embodiment of a slurry tanker according to the present invention; Fig. 11 shows an schematic drawing corresponding to Fig. 1 of a further embodiment of a slurry tanker according to the present invention; and

Fig. 12 shows a schematic drawing which is a modified embodiment of the design shown in Fig. 7.

Detailed Description of the Invention

In Fig. 1 of the drawing appears a schematic drawing showing a slurry tanker and valve arrangements and piping for a slurry tanker according to the present invention. In Fig. 1 , the following elements appear:

Tank 1 of slurry tanker to be filled. When ejector 6 is to be used, one has to start with a suitable amount of liquid in the tank 1.

Slurry pump 2 pumping slurry out of the slurry tank 1 via a discharge line 49. The pump may be hydraulically, electrically or diesel powered.

Three-way valve 3 that may be used for choosing between using ejector system or normal spreading.

Three-way valve 4 used for regulation of dose by spreading on a field.

Spreader 5 for spreading on field.

Ejector 6 used at initial suction for filling the tank 1. By circulating through the ejector 6, vacuum arises in branch line, in valves 7 and 9. This branch line constitutes a return line 50 to the tank 1.

Slurry valve 7 providing the possibility of sucking through hose, e.g. manually mounted from another slurry tanker (not shown).

Coupling 8 for use in mounting hose from another slurry tanker.

Slurry valve 9 providing the possibility of sucking through suction line/hose 20 in the filling crane of the slurry tanker which in a known way positions the hose 20 in a slurry container 16 to be emptied.

Slurry valve 10 which closes normal connection between a feed line 48 and the hose 20 on the filling crane of the slurry tanker to the tank 1 of the slurry tanker. By closed slurry valve 10, one may aspirate the slurry and lift it up to a not self-priming slurry pump 13. Air valve 11 which is closed when sucking, and which is opened when the tank 1 is foil so that the slurry in the hose 20 of the crane can run back to the slurry container 16. The air valve provide for avoiding siphoning effect and emptying the tank 1 of the slurry tanker. The slurry from the crane hose 20 is delivered low in the slurry tanker tank 1 in order to avoid foam.

Extension 12 on the crane for adapting to various positions of slurry containers 16. The extension 12 is to be 100% tight in order to obtain aspiration.

Slurry pump 13 which is normally submerged in the slurry in the slurry container 16. The pump is not self-priming and is preferably liquid-driven.

Slurry valve 14 disposed at the extreme end of the hose 20. By closing the slurry valve 14, one may let the hose 20 of the crane be foil with slurry after filling. With the valve 14 closed, the crane may be aspirated during transport. Thereby, the aspiration time is reduced at the next filling.

Coupling 15 towards the slurry container 16. The coupling 15 is to be tight in order to obtain enough vacuum to lift the slurry up from the slurry container 16 to the slurry pump 13.

Flow meter 17 that measures the amount of slurry spread.

Manometer 18.

Return line 19 from the slurry tanker tank 1 to the slurry container 16.

Normally, the valves 3, 4, 9, 11, 14 are remote controlled as they are to be operated at each filling of the tank 1. The valves 7, 9 are normally manually operated, as they are only operated in another method of filling.

In order to fill the pump 13 with slurry without the need of lowering into the slurry container 16, a return line 50 to the tank is provided in connection with the emptying pump 2. In this return line 50, an ejector 6 is disposed and connected to a pressure source for a medium for establishing ejector action. The ejector has a suction line 51 which via a shut-off valve 9 can be connected to the filling pump 13 for aspirating the slurry through the filling pump.

Figs. 2 - 4 show an ejector for use in the system shown in Fig. 1.

In Fig. 4, 21 designates external nozzle pipes. 22 designates an internal nozzle for ejector. 23 designates a transition piece with flanges. 24 designates bolts for mounting. 25 designates washers for use in clamping the flange connection, and 26 designates nuts for use in clamping the flange connections by which the ejector is secured to the lines of the slurry tanker.

In the following, various modes of operation are described.

Firstly, there is described a first situation of use of the system. It is noted that there is provided a description which does not include the valve 14.

Normal slurry is applied without too much entrained air (straw, feed residues, lumps of dung and other may hold air).

The slurry is spread on the field. When there is an appropriate amount of slurry left in the tank 1 of the slurry tanker, the spreading is stopped, and one returns to the slurry container 16 to be emptied. By an appropriate amount is meant an amount which is sufficient to get the ejector 6 to operate in a satisfactory way. This amount will normally be about 3 m³.

The slurry tanker is now ready for filling by using the ejector 6. This occurs by activating the pump 2 with the valve 3 in straight position. The valve 4 is set to suitable dosing by means of data from the flow meter 17.

The valve 9 is opened and is to stand in this position as long as one wants to use ejector/crane. The valve 11 is shut.

The valve 10 is shut.

The valve 3 shifts position so that slurry goes to the ejector 6.

The crane places the hose 20 in rilling position so that the coupling 15 is tight. This normally occurs by pressing the crane coupling 15 against the coupling 28 of the slurry container. The outermost end of the hose 20 is equipped with a flexible rubber joint 27 that may be seen on Fig. 5.

The flexible rubber joint 27 is necessary for the system to operate when the slurry tanker rocks and sinks down in the suspension due to increased load. As may be seen from Fig. 5, the crane may have a considerable length, and therefore the position of the coupling 15 may be released from engagement with the coupling 28 of the slurry container if the flexible rubber joint 27 had not been provided.

The slurry pump 2 is started, and vacuum occurs in the connection down to the coupling 15 by the flow of the slurry through the ejector 6 and back to the slurry tanker tank 1. When the vacuum has become sufficiently large (can be read on the manometer 18), the slurry is lifted up to the slurry pump 13 of the crane.

Shortly after starting the slurry pump 2, the crane pump 13 is also started.

When the slurry comes up to the pump 13, it will pump faster into the slurry tanker tank 1 than allowed by the capacity of the ejector 6, and the vacuum on the manometer 18 will drop.

When the pump 13 is filled with slurry, the valve 10 may be opened and the pump 2 switched off. Now slurry is pumped from the container 16 directly into the slurry tanker tank 1 only by means of the crane pump 13. When the slurry tanker tank 1 is full, the return line 19 will make the slurry run back to the slurry container 16, and possible foam formation will come out of the slurry tanker tank. Thereby 100% filling is attained.

When the tank 1 of the slurry tanker is full, the crane pump 13 can be stopped simultaneously with opening the valve 11. Hereby, air may come into the crane hose 20, and slurry in the crane hose 20 may run out without risking initiation of emptying the tank 1 again due to a siphoning effect. Alternatively, there may be used a valve 14 which will close when the tank 1 is full. Closing the valve 14 will also obviate the risk of emptying the tank 1 due to siphoning effect.

The crane is placed in driving position on the slurry tanker.

The valve 3 shifts position so that the slurry can be spread out on the field.

Then the above operation can be repeated.

hi another situation of use, when working with heavy slurry that may cause centrifugal pumps to cavitate because of air pockets, there will be the following mode of operation:

Operations as mentioned above are performed, with the exception that one does not stop the pump 2, one opens valve 10 completely or partly and is ready all the time to close valve 10 when crane pump 13 cavitates. Then filling with ejector 6 is continued until the vacuum on manometer 18 again drops, and the valve 10 may again be opened completely or partially.

The above filling may also be performed with the valve 10 closed all the time, however with less capacity.

Moreover, as mentioned there may be provided an alternative embodiment where the valve 14 is mounted in the hose 20 of the slurry tanker. On the way back to the farm from the field, one may do as described above with the advantage that the slurry pump 2 can be started before the crane has put the hose in contact with the slurry container. This means that a closed valve 14 provides that one may prepare the system by subjecting it to vacuum during transport. As soon as the crane has placed the hose 20 in contact with the slurry container 16 and the couplings 15, 28 are engaged, valve 14 is opened and the slurry it lifted rapidly up to the crane pump 13, and optimal filling by means of the crane pump 13 is operating.

Instead of emptying the crane hose after filling by letting air into the hose 20, one may thus close the valve 14 with the valve mounted in the hose 20, thereby avoiding that the slurry runs out of the crane hose again. However, this puts a great load on the crane due to the weight of the slurry and causes overfilling of the slurry tanker.

In Figs. 6 - 9 appear a further embodiment of application of a slurry tanker according to the invention. In this embodiment is used a coupling of the slurry tanker via a docking station 29 which is provided in connection with the slurry container 16 to be emptied. In these figures, a valve 14 as explained above with reference to Fig. 1 is not shown. However, a valve 14 may also be relevant in connection with these embodiments.

Here is seen an example of coupling where, via a pivoting arm 30 on the slurry tanker, there is performed a coupling to the docking station 29 which is connected to the slurry container.

The slurry tanker operates according to the same principle as the slurry tanker described above with reference to_. Figs. 1 - 5.

On Fig. 8 and Fig. 9 is shown a first system interacting with the docking station 29.

Here is shown an example of coupling where the pivoting arm 30 on the slurry tanker is provided with a slurry pump 13. The new feature is that the slurry container 16 is equipped with a fixed tube connection 30 to the docking station 29. The docking station 29 includes a tank 31, a valve 32 which blocks the path of slurry from slurry container to a coupling in the form of a docking funnel 33. At the docking funnel 33 is placed a suction pipe 34 with valve 35.

In this embodiment is used the same functionality of aspirating with the ejector 6 as previously described. When sufficient vacuum has been established in the system, the valve 32 is opened, and when the filling pump 13 is filling in a stable way, the direct connection to the tank through valve 36 is opened. When the slurry tanker is full, surface foam will come out of the return hose 19 which delivers it down into the tank 31 of the docking station.

When the docking station tank 31 is full, it may be emptied by opening the valve 35 during the next filling of the tank 1 of the slurry tanker. The connection from the docking funnel 33 to the valve 35 is to be designed in such a way that a sufficient flow from the slurry tanker tank 1 produces vacuum in suction pipe 34.

The valve 35 may of a type which is actuated when needed, or may alternatively be a float valve that opens automatically when a certain slurry level is present in the tank 31.

In Fig. 6 and Fig. 7 is shown a second system interacting with the docking station 29.

Here is shown an example of coupling where the pivoting arm 30 on the slurry tanker is without a slurry pump.

The difference compared with the above example is that the slurry tanker is only equipped with one slurry pump 2, namely the normal spreader pump 2. This pump 2 is activated, and when filling is going on, the three-way valve 37 is actuated so that the vacuum present at the suction side of the spreader pump 2 is used for sucking slurry to the spreader pump 2 which is now acting as a filling pump. In this embodiment, there will always be slurry residue in the tank 1 providing pressure in the pump 2. With the valve 37 is semi-open position, there will still be a flow. If air is carried into the pump 2 during operation, slurry will automatically be fed into the pump 2 from the tank 1.

As alternative to a liquid-driven ejector 6, an air ejector 38 may be used. An example of the latter is shown in Fig. 12, which is a modified embodiment of the design shown in Fig. 7. An air-powered ejector may, however, be applied in connection with any embodiment of a system according to the invention.

The air-powered type of ejector will be particularly suited in connection with slurry tankers with air brakes. That means in applications where a tractor used for towing the slurry tanker is having an air compressor which may fill an air bottle 39 of appropriate size for producing the required vacuum in the ejector. The air bottle 39 is connected to the ejector 38 via a valve 40.

Li Fig. 10 is shown a variant of the system shown in Fig. 1.

In addition to the elements shown in Fig. 1, the following elements are shown in Fig. 10:

A hydraulic cylinder 41 for actuating the valve 10.

An accumulator 42 which typically will be an accumulator charged in advance with a pressure of 100 bar.

A hydraulic motor 43 driving a slurry pump 13 and connected with a supply via a pressurised hydraulic line 44 and a return tank (not shown) via a return hydraulic line 45. A stone trap 46 is to catch large foreign objects before they reach the ejector 6. Hereby the risk of clogging of the ejector 6 is reduced. The stone trap 46 is provided with a valve 47 for simple and rapid emptying of the stone trap 46.

If air comes into the system/pump 13, so that a pressure drop occurs in the crane hose 20, in the present embodiment it will occur that the accumulator 42 actuates a piston in the hydraulic cylinder 41. This will actuate the valve 10 so that no slurry will be sent into the tank 1 via the feed line/feed pipe 48. Instead, the slurry is conducted through the ejector 6. In this way an automatic activation of the ejector circuit will be effected in case of failing supply of slurry in the pump 13.

In Fig. 11 is shown a further variant of the system shown in Fig. 1.

In Fig. 11 , some elements are removed compared to the elements shown in Fig. 1. The three-way valve 3 is removed compared with Fig. 1. The valve 10 has been moved into the tank 1, and the ejector 6 has been moved into the tank 1. Operation and thereby use of the slurry tanker is hereby facilitated.

Claims

1. A slurry tanker with a tank having an feed line with a filling pump for filling with slurry for pumping the slurry to the tank, and a discharge line with an emptying pump for pumping slurry out of the tank, where the lines are provided with valves for optional shutting off/connecting between the pumps and the tank, characterised in that that a return line to the tank is provided in connection with the emptying pump, that in this return line an ejector is disposed and connected with a pressure source for a medium for establishing an ejector action and which has a suction line which via a shut-off valve may be connected with the filling pump for aspirating the slurry through the filling pump .

2. Slurry tanker according to claim 1, characterised in that the pressure source is provided by the pressure side of the emptying pump.

3. Slurry tanker according to claim 1, characterised in that the pressure source is provided by an air compressor.

4. Slurry tanker according to claim 3, characterised in that the pressure source furthermore includes an air bottle.

5. Slurry tanker according to any preceding claim, characterised in that the filling pump and the emptying pump are provided in the form of centrifugal pumps.

6. Slurry tanker according to any preceding claim, characterised in that the ejector is disposed in the tank of the slurry tanker.

7. A method for filling a slurry tanker with a tank having an feed line with a filling pump for filling with slurry for pumping the slurry to the tank, and a discharge line with an emptying pump for pumping slurry out of the tank, which lines being provided with valves for optional shutting off/connecting between the pumps and the tank, characterised in that there is provided an ejector action in a return line connecting the emptying pump with the tank, and that this ejector action is used for establishing a vacuum which is connected to the pressure side of the filling pump in order to aspirate slurry through the filling pump.

8. Method according to claim 7, characterised in that the ejector action is provided by the pressure side of the emptying pump.

9. Method according to claim 7, characterised in that the ejector action is provided by an air compressor.

10. Method according to claim 9, characterised in that the ejector action is provided by an air compressor associated with a tractor used for towing the slurry tanker.