EP2191072B1

EP2191072B1 - Continuous mixer and dispenser of mortar for filling channels, trenches or excavations

Info

Publication number: EP2191072B1
Application number: EP08806953.9A
Authority: EP
Inventors: Angelo Leo; Edoardo Cottino; Luca Gersony; Martin Maier
Original assignee: Agres Srl; Sirti SpA
Current assignee: Agres Srl; Sirti SpA
Priority date: 2007-09-07
Filing date: 2008-08-25
Publication date: 2015-06-17
Anticipated expiration: 2028-08-25
Also published as: EP2191072A1; WO2009030999A1; ES2546728T3; ITMI20071736A1

Description

The present invention refers to a continuous mixer/dispenser of mortars for filling channels, trenches or excavations.
In particular, the present invention refers to a mixer/dispenser of mortars for filling channels, trenches or in general excavations made to lay cables underground in carriageable and/or pedestrian areas.
The laying of cables underground takes place substantially according to the following steps in succession

preliminarily checking, and advantageously with non-invasive methods (like, for example, the use of Georadar techniques), for the possible presence of pre-existing underground services in the excavation area
making an excavation of predetermined depth and width,
laying one or more cables or a duct suitable for the subsequent laying of one or more cables inside such an excavation,
covering the excavation itself and the duct or the cable buried in it making the area suitable for traffic once again.

Normally excavations or ducts suitable for receiving one or more cables, for example electrical or fibre optic, are made on the road surface, for example on its side edges, on the verge, or in some cases directly on the pavement.
The works are usually carried out by making the excavation in open air, laying the duct or the cable and covering the excavation itself with earth or gravel and then restoring the asphalt or the original covering removed while making the excavation.
During such steps, and especially in highly urbanised areas, or areas of particular architectural significance like for example the historical centres of cities, the time taken to perform the aforementioned works, the size of the necessary machinery and the environmental impact of such works are extremely critical. Indeed, the presence of a worksite or in any case the clogging up of the road surface, of the pavement or of the verge causes substantial disturbance, both for pedestrians and for road vehicles, linked to the size of the worksite and the time taken to complete the excavation work.
In the case of excavations in areas of particular esteem, the works must be carried out with special care to avoid polluting and degrading the work area and the surrounding areas.
In the art are known some devices as described in their respective documents.
For example, US 4 117 547 discloses an apparatus for the preparation of mortar, which apparatus has a wheel-mounted frame for an elongated vessel which receives metered quantities of solid and liquid constituents from discrete feeding units. The vessel has an outlet and contains a rotary homogenizing and evacuating device which mixes the solid and liquid constituents to form mortar and advances the mortar toward and through the outlet. Mortar issuing from the outlet of the vessel can be discharged into a separate container which is mounted in or on the frame and is connected with one or more evacuating pumps, into wheelbarrows or into the container of a conventional mortar mixing machine. The feeding unit for solid constituent may receive material by gravity flow or under the action of a rotary screw in a receptacle which is mounted in the frame at a level above the vessel and receives solid constituent from a pneumatic conveyor. The quantities of mortar in the container and of solid constituent in the receptacle are monitored by discrete detector means which arrest one or more prime movers for the moving parts of the apparatus when the quantity of mortar in the container or the quantity of solid constituent in the receptacle exceeds a predetermined quantity. The rates of admission of constituents into and of evacuation of mortar from the vessel are selected in such a way that the vessel contains a constant supply of mortar but is not filled to capacity.
Therefore, minimising the size of the worksite, making the works as fast as possible and working avoiding pollution are very important objectives, given the increase in cabling due to the huge spread of new multimedia technologies (both over electrical cables and over fibre optic cables), for the general public or for businesses or public bodies.
In particular, the step of filling in the excavation and restoring the pre-existing verge or surfacing must be fast and flexible, in the sense of adapting to the conditions and the contingent needs.
The machinery used must also allow a possible recovery of the efficiency of the equipment directly in situ avoiding dirtying and pollution of the work area and, at the same time they must be small in size.
The Applicant has made an optimised, fast and efficient method to carry out the laying of cables or ducts underground that meets the aforementioned requirements, in which the size of the trench is foreseen to be very small, the size of the machinery used are kept small, the material removed from the channel can be immediately taken in and in which the filling of the channel itself after the laying of the duct or of the cable is carried out with a quick-setting material and is compatible with the requirements of a pavement or a road surface.
Having to thus restore the surfacing and the pre-existing traffic in short periods the mortar must be relatively fast-setting and consequently the machine must be able to carry out the various steps quickly to allow a correct laying and levelling of the filling at the same time avoiding drawbacks of solidification inside the machine itself or of expensive excessive waste of filling material.
The devices according to the prior art usually operate in discontinuous "batch" mode, i.e. being loaded one batch at the time.
Such a mode is not flexible and is not suited either to making small-sized fillings with quick-setting material, or to the variability in size of the excavations to be filled since it is difficult to foresee and calculate the amount of filling material to use in each load.
Indeed, once the mixing of the batch has begun, all of the mortar has to be used and the machine has to be emptied to avoid the solidification of the mortar inside.
The Applicant has therefore set itself the problem of how to achieve the filling of excavations of variable dimensions and of small size in a flexible manner and in small spaces.
Therefore, the Applicant proposes, according to the present invention, a continuous dispensing mixer of mortar for filling channels, trenches or excavations capable of carrying out the optimised filling of the excavation in which the cables are laid using even fast-setting material.
An aspect of the present invention therefore concerns a continuous mixer/dispenser of mortar for filling channels, trenches or excavations. Said mixer/dispenser is defined in claim 1 and essentially comprises:

at least one tank for separately containing solid materials such as binders and possible additives and inerts;
a premixing chamber of said solid materials;
a system of batching plants of said solid materials from said at least one tank to the premixing chamber;
a premixing conveyor of the solid materials;
(all of the previous elements are made to be airtight);
a mixing chamber for preparing the mortar through mixing of the solid materials transported by said premixing conveyor, with water;
a tank of water connected to said mixing chamber to feed the water;
a pump connected to said tank of water to pressurise the water contained in the tank to the desired value;
an adjustment system, flowmeter, that allows the amount of water to be entered into the mixing chamber to be controlled;
a dispensing system of the mortar into the channel, trench or excavation to be filled, in turn fed by the mixing chamber.

The characteristics and advantages of the continuous mixer/dispenser of mortar for filling channels, trenches or excavations according to the present invention shall become clearer from the following description, given as an example and not for limiting purposes, referring to the attached schematic drawings, in which:

figure 1 is a schematic figure of the main components of the dispensing mixer according to the present invention;
figure 2 schematically illustrates the dispensing mixer according to the present invention;
figures 3 and 4 schematically illustrate as many constructive details of the dispensing mixer according to the present invention.

With reference to the quoted figures, in an excavation 5 made through asphalt 1 and earth 2 an infrastructure 3 is installed made up of one or more pipes and/or cables; the excavation is then filled in with suitable filling material 4 in general a mortar, according to the preferred embodiment of the invention a low-shrinkage and fast-setting mortar of cement, comprising a suitable binder L possibly mixed with additives, inerts I and mixing water W.
The following steps are carried out in succession. A first step of checking for the possible presence underground of pre-existing services that would interfere with (or would be damaged by) the excavation work. This check can be carried out preliminarily and independently from the excavation work or, more advantageously, it can be carried out with non-invasive methods (like, for example, the use of Georadar techniques) with machinery immediately in front of that which will carry out the excavation and that performs checks as it advances. The checking can be immediately followed by the making of an excavation or trench 5 of extremely small dimensions. For example, and in a nonlimiting way, dimensions compatible with the requirements indicated previously are an excavation of depth of about 20 to about 50 cm and of width between 3 and 10 cm. A device for inspecting the subsoil analyses for the presence of possible pre-existing underground services for the depth involved in the excavation and precedes a small machine for milling the earth preferably comprising a trench-cleaning blade and possibly a suitable sucking device, which moves in synchrony with a moving device, and which is suitable for sucking in the material removed from the excavation at the same time as the production of the material itself, so as to produce a trench ready for the laying of the duct or cable inside of it, immediately after the machine and the suction device have passed over the part of trench made.
The device for analysing the subsoil is positioned at the front of the work train, which allows the excavation work to be stopped or adjusted through suitable servo control.
The small size of the excavation trench allows the size of the machinery used to be kept small, thanks to the small amount of material removed. Moreover, the suction device can be used to remove the material in the parts of the trench that can have other underground services passing through them, avoiding damaging them.
The dispensing mixer 100 according to the invention is mounted on a suitable vehicle preferably connected to the machine group to move in synchrony with the excavation miller and with the device for laying the cables so as to carry out the filling of the excavation continuously allowing traffic to pass over the excavation, in the relatively short periods necessary for the solidification of the filling material.
A material suitable for filling the excavation is a mortar for example a quick-setting mortar of cement that can be cast with controlled shrinkage, mixed with suitable inerts and possibly fine gravel for mortar with characteristics of being able to support traffic a short time after laying.
The continuous mixer/dispenser 100 of mortars 4 for filling channels, trenches or excavations 5 comprises:

at least one tank 101,101a,101b for separately containing solid materials such as binders and possible additives L and inerts I;
a premixing chamber 110 of said solid materials;
a system of batching plants 102,103 of said solid materials from said at least one tank 101 to the premixing chamber;
a premixing conveyor 105 of the solid materials; (all of the previous elements are made to be airtight)
a mixing chamber 120 for preparing the mortar through mixing, with water W, of the solid materials transported by said premixing conveyor 105;
a tank 101c of water W connected to said mixing chamber to feed it with water;
a pump 163 connected to said tank 101c of water W for pressurising the water contained in the tank to a desired value;
an adjustment system or flowmeter 164, which allows the amount of water W to be entered into the mixing chamber 120 to be controlled;
a dispensing system 140 of the mortar 4 into the channel, trench or excavation 5 to be filled, in turn fed by the mixing chamber.

The dispensing mixer 100 can comprise single tank 101 made in the form of a container with separate tanks 101a,101b,101c inside of it intended to contain the components of the mortar and thus suitably sized, or else it can comprise the tanks 101a,101b,101c positioned separately.
The premixing chamber 110 of the solids is fed with the binder and possible additives and the inerts coming respectively from the tanks 101a and 101b through a system of batching plants made through first Archimedean screws, an Archimedean screw 102 for the binder and an Archimedean screw 103 for the inerts. Such Archimedean screws 102 and 103 are installed in suitable ducts, are each made to rotate by a relative motor, the Archimedean screw 102 for the binder is actuated by first motor M1 and the Archimedean screw 103 for the inerts is actuated by a second motor M2. Both of the Archimedean screws 102 and 103 are calibrated and adjustable in flow rate through adjustment of the motors M1 and M2 so as to feed the premixing chamber batching the solid components in a controlled and programmable manner.
One or both of the Archimedean screws 102 and 103 are also provided, at the mouth, with corresponding presence sensors of the material, 160 and 161 respectively that can be connected through respective lines 152,153 to a central processing and control unit 150 or else they can be controlled manually directly and separately to control and indicate the lack of binder or of inert or of both.
The purpose of such adjustments is to be able to adapt the mixing according to the binders and inerts used to make the mortar in a predetermined way.
The Archimedean screw 102 for the binder feeds a predetermined amount of material and the Archimedean screw 103 for the inerts is adjusted to make the correct premixing ratio in the chamber 110, also in the case of stopping the dispensing, the feeding of solids can also be stopped avoiding the clogging up of the premixing chamber 110.
The premixing chamber 110 has a square shape with substantially vertical side walls 111 tapered towards the base and joined by a substantially cylindrical base plate 112 in which along the longitudinal axis a premixing conveyor 105 is arranged in the form of a second Archimedean screw 105 made to rotate by a third motor M3.
The rotation of the two first Archimedean screws 102,103 is carried out in opposite directions, in particular each one rotates towards the relative side wall 111 of the premixing chamber so as to feed the solid making it fall near to the corresponding side wall.
The premixing conveyor 105 causes the mixture of solids to advance mixing it further so as to homogenise its composition and conveys the material to the mixing chamber where, through feeding of water W with predetermined pressure and amounts, the mortar is made to fill the excavation.
In the premixing chamber a level sensor 162 of the material is also foreseen that can be directly provided with an actuator for shutting off/restarting the feed of solids once predefinable respective full/empty thresholds of the premixing chamber have been reached or it can be connected to the central unit 150 through a line 154 for processing and controlling the operations.
The premixing conveyor 105 discharges the solid mixture into the mixing chamber 120 that is made in the form of a hollow cylindrical body 121 in which a shaft 122 with paddles 123 rotates axially and in which the water W is fed from a pipe 104 connected to the pump 163 for pressurisation and prior to the water tank 101c.
The flow rate of water W is controllable and adjustable through the flowmeter 164 connected through a line 151 to the corresponding transducer arranged in the central unit 150.
In the mixing chamber 120 the mortar is obtained by mixing the solids with a predetermined amount of water. The shaft 122 with paddles 123 also takes care of transporting the mortar up to the end of the mixing chamber discharging it in a hopper container 130 equipped with a level sensor/actuator 131 arranged to control the stopping of feeding of the entire mixer in the case in which a threshold level of mortar has been reached in the container 130.
The hopper container 130 is connected to the dispensing system 140 of the mortar in the channel, trench or excavation to be filled and feeds said system with the mortar.
The dispensing system 140 of the mortar is made in the form of a tubular element 144 at least partially flexible to adapt to the shapes of the excavations and be directly aimed by the operator.
The mortar is pushed forward through a thruster 145 preferably made in the form of a helical blade made to rotate by a motor 141 connected to an end of the tubular element 144.
Such a thruster 145 is preferably made from spring steel whereas the tubular element 144 is made from rubber or from a suitable flexible and strong material with a suitable steel core embedded inside it.
Advantageously, the thruster 145 in the form of a helical blade, allows the mortar to be dispensed continuously independently from the composition thereof so as to avoid possible drawbacks of composition since such a thruster carries out a continuous mixing of the mortar together with moving it forward.
The motor 141 for rotating the thruster is of the type using an inverter with continuous adjustment of the rotation speed, from zero to the maximum, so as to adapt the dispensing to the setting times of the mortar and possibly stop the supply of mortar and if necessary empty the dispensing system.
Advantageously, the dispensing system can be equipped, at the mouth, with a support trolley 146 in turn equipped with a shaver 147 for levelling off the mortar.
In order to clean the components of the mixer, it is advantageously possible to foresee a pull-out tub 170 arranged under the tank 101, able to be withdrawn and slide on guides, to receive the components for their washing able to be carried out directly with the water obtained from the tank 101c.
The components of the mixer are foreseen to be easy to assemble/disassemble and are made from materials that mortar cannot attach to.
In particular, the premixing chamber is provided with bayonet attachments and the dispensing system is provided with flanges for attachment to the hopper container 130.
Both the thruster 145 an the tubular element 144 can thus be easily dismounted and cleaned in the tank 170, in particular the tubular element 144 is provided with a flange with suitable attachment 147 to connect a flow rate of pressurised water to clean the tube through a sponge ball introduced inside it and thrusted by the pressurised water.

Claims

Continuous mixer and dispenser (100) of mortar for filling channels, trenches or excavations (5) comprising:
- a premixing chamber (110) of solid materials;

- a premixing conveyor (105) of the solid materials;
a mixing chamber (120) for preparing the mortar through mixing, with water (W), of the solid materials transported by said premixing conveyor (105);

- an adjustment system or flowmeter (164), which allows the amount of water (W) to be entered into the mixing chamber (120) to be controlled;

- a dispensing system (140), of the mortar into the channel, trench or excavation to be filled, in turn fed by the mixing chamber;
said continuous mixer and dispenser being characterized in that it comprises:
- at least one tank (101, 101a, 101b) for separately-containing said solid materials such as binders and possible additives (L) and inerts (I);

- a system of batching plants (102, 103) of said solid materials from said at least one tank (101, 101a, 101b) to the premixing chamber, said batching system, said premixing chamber and said at least one tank being kept airtight;

- a tank (101c) of water (W) connected to said mixing chamber (120) to feed it with water;

- a pump (163) connected to said tank (101c) of water (W) to pressurize the water contained in the tank to the desired value;
wherein the premixing chamber (110) of the solids is fed with the binder and possible additives and the inerts coming respectively from the tanks (101a, 101b) through a system of batching plants made through first Archimedean screws, an Archimedean screw (102) for the binder and an Archimedean screw (103) for the inerts; wherein said Archimedean screws (102, 103) are installed in suitable ducts and are calibrated and adjustable so as to feed the premixing chamber batching the solid components.
Continuous mixer and dispenser (100) according to claim 1, wherein said Archimedean screws (102,103) are provided with corresponding presence sensors of the material (160,161) that can be connected through respective lines (152, 153) to a central processing and control unit (150) or else they can be controlled manually, directly and separately.
Continuous mixer and dispenser (100) according to claim 1, wherein said premixing chamber (110) has a substantially square shape with substantially vertical side walls (111) tapered towards the base and joined by a substantially cylindrical base plate (112) in which along the longitudinal axis the premixing conveyor (105) is arranged in the form of a second Archimedean screw.
Continuous mixer and dispenser (100) according to claim 3, wherein in said premixing chamber (110) a level sensor (162) of the material is also foreseen that can be provided directly with an actuator for shutting off/restarting the supply of solids once predefinable respective full/empty thresholds of the premixing chamber have been reached or it can be connected to the central processing and control unit (150) of the operations through a line (154).
Continuous mixer and dispenser (100) according to claim 1, wherein said mixing chamber (120) is made in the form of a hollow cylindrical body (121) in which a shaft (122) with paddles (123) rotates axially and in which the water (W) is fed from a pipe (104) connected to the pump (163) for pressurization and prior to the water tank (101c), the flow rate of water (W) being controllable and adjustable through the flowmeter (164) connected through a line (151) to the corresponding transducer arranged in the central unit (150).
Continuous mixer and dispenser (100) according to claim 5, wherein said shaft (122) with paddles (123) also takes care of transporting the mortar up to the end of the mixing chamber and discharging it in a hopper container (130) equipped with a level sensor/level actuator (131) arranged to make the supply of the entire mixer stop in the case in which a threshold level of mortar is reached in the container (130).
Continuous mixer and dispenser (100) according to claim 6, wherein said hopper container (130) is connected to the dispensing system (140) of the mortar into the channel, trench or excavation to be filled and feeds said system with the mortar.
Continuous mixer and dispenser (100) according to claim 1, wherein said dispensing system (140) of the mortar comprises a tubular element (144) at least partially flexible in which a rotary thruster (145) is foreseen assembled, preferably made in the form of a helical blade made to be rotated by a motor (141) connected to an end of the tubular element (144).
Continuous mixer and dispenser (100) according to claim 8, wherein said thruster (145) is made from spring steel whereas the tubular element (144) is made from rubber or a suitable flexible and strong material with a suitable steel core embedded inside it.
Continuous mixer and dispenser (100) according to claim 9, wherein said motor (141) for rotating the thruster is of the type using an inverter with continuous adjustment of the rotation speed, from zero to maximum.
Continuous mixer and dispenser (100) according to claim 10, wherein said dispensing system (140) is equipped at the mouth with a support trolley (146) in turn equipped with a shaver (147) for levelling off the mortar.
Continuous mixer and dispenser (100) according to claim 1, wherein said dispensing mixer (100) comprises a pull-out tub (170) arranged under the tank (101), able to be withdrawn and slide on guides, to receive the components to wash them, which can be carried out directly with the water that can be obtained from the tank (101c).
Continuous mixer and dispenser (100) according to claim 1, wherein said dispensing mixer (100) comprises a single tank (101) made in the form of a container with separate tanks (101a, 101b, 101c) inside of it, intended to contain the components of the mortar and thus suitably sized.