FIELD

[0001] The improvements generally relate to concrete mixer trucks and more specifically to loading concrete ingredients into drums of such concrete mixer trucks.

BACKGROUND

[0002] Fresh concrete is formed of a mixture of concrete ingredients including at least cementbased material, aggregates and water in given proportions. The proportions of each concrete ingredient can be provided in the form of a recipe, and different recipes can lead to fresh concrete mixtures having different mechanical properties.

[0003] The concrete ingredients of a new recipe are typically loaded inside an empty drum of a concrete mixer truck at a concrete production plant. To handle the recipe of fresh concrete, the drum generally has one or more spiraled blades that, depending on a direction of the spiraled blade, either mix the concrete ingredients into fresh concrete within the drum or force the fresh concrete towards a discharge outlet of the drum. Concrete ingredients are loaded into the drum while the drum is rotated in a mixing direction to promote mixing of the concrete ingredients as soon as they are loaded into the drum. Once loaded into the drum, the concrete ingredients are mixed at higher rotation speeds for a given amount of time until a homogeneous mixture is obtained, after which the drum is agitated by rotation at lower rotation speeds to avoid hardening prior to being discharged at a job site.

[0004] At the job site, the drum is rotated in an unloading direction which, depending on the quantity of fresh concrete inside the drum, may require a given number of rotations to fully discharge the fresh concrete. Even if the drum is deemed to be fully discharged, for instance after the given number of rotations of the drum in the unloading direction, there may remain water at the bottom of the drum. If remaining water goes unnoticed, loading a subsequent recipe of concrete ingredients into the wet drum can modify the proportion of water in the recipe which can in turn adversely affect the performance of the fresh concrete when hardened. In some circumstances, visual inspection of the drum is performed prior to loading a new recipe into the drum to avoid water excess.

[0005] Although existing techniques for loading concrete ingredients into the drum of the concrete mixer truck are satisfactory to a certain degree, there remains room for improvement.

SUMMARY

[0006] There is described methods and systems for loading concrete ingredients into a drum of a concrete mixer truck. Broadly described, the drum is rotated into a mixing direction. As the drum rotates into the mixing direction, the water detector measures a quantity of water remaining at a bottom of the drum as the drum rotates during at least one full rotation. The quantity of water can be quantified in terms of volume, weight or any other suitable measurand depending on the embodiment. In some embodiments, the water detector is precise enough to measure the quantity of water remaining in the drum in a satisfactory manner. A recipe of concrete ingredients to be loaded into the drum is then modified based on the measured quantity of water. The recipe is modified to determine a top up water quantity corresponding to a difference between a total quantity of water of the recipe and the measured quantity of water remaining into the drum. Once determined, the modified recipe of concrete ingredients is loaded into the drum in which only the top up water quantity is added into the drum. By doing so, a situation where too much water is loaded into the drum can be avoided. Extra steps of removing water out of the drum prior to the loading of the concrete ingredients of the new batch can also be avoided.

[0007] In accordance with a first aspect of the present disclosure, there is provided a method of loading a recipe of concrete ingredients into a drum of a concrete mixer truck, the recipe including a total quantity of water, the method comprising: rotating the drum into a mixing direction; using a water detector mounted to an inside wall of the drum, measuring a quantity of water remaining at a bottom of the drum as the drum rotates; modifying the recipe of concrete ingredients based on said measured quantity of water, said modifying including determining a top up water quantity corresponding to a difference between the total quantity of water of the recipe and the measured quantity of water; and loading the modified recipe of concrete ingredients into the drum, said loading including adding only the top up water quantity into the drum.

[0008] Further in accordance with the first aspect of the present disclosure, said measuring the quantity of water can for example include determining a first position at which the water detector enters into water and a second position at which the water detector exits water, and determining the quantity of water based on the first and second positions.

[0009] Still further in accordance with the first aspect of the present disclosure, said water detector can for example include an interface exposed within the drum, the interface moving in back-and-forth sequences and experiencing a resistance to movement imparted by an immediate surrounding of the interface.

[0010] Still further in accordance with the first aspect of the present disclosure, said measuring can for example include measuring a plurality of resistance response values indicative of said resistance to movement over at least a rotation of the drum, identifying first and second positions at which the resistance responses values cross a given threshold, and determining the quantity of water based on the first and second positions.

[0011] Still further in accordance with the first aspect of the present disclosure, the water detector can for example include an electromechanical actuator having the interface, the interface moving upon actuation of the electromechanical actuator with an electrical signal.

[0012] Still further in accordance with the first aspect of the present disclosure, said moving can for example include vibrating the interface at a single frequency.

[0013] Still further in accordance with the first aspect of the present disclosure, the single frequency can for example range between about 200 and 1,000 Hz, preferably between about 500 and 700 Hz and most preferably at about 650 Hz.

[0014] Still further in accordance with the first aspect of the present disclosure, said rotating can for example include rotating the drum at a rotation speed below 10 rotations per minute, preferably below 5 rotations per minute, and most preferably below 3 rotates per minute. [0015] Still further in accordance with the first aspect of the present disclosure, the method can for example include, after said loading, increasing a rotation speed of the drum above a rotation speed threshold for a given number of rotations.

[0016] Still further in accordance with the first aspect of the present disclosure, the method can for example comprise moving the concrete mixer truck into a loading location prior to said loading.

[0017] In accordance with a second aspect of the present disclosure, there is provided a system for loading a recipe of concrete ingredients into a drum of a concrete mixer truck, the recipe including a total quantity of water, the system comprising: a water detector mounted inside the drum, the water detector being configured for measuring a quantity of water remaining at a bottom of the drum as the drum rotates; and a controller being communicatively coupled to the water detector, the controller having a processor and a memory having stored thereon instructions that when executed by the processor perform the steps of: receiving a rotation signal indicative of a direction of the drum; modifying the recipe of concrete ingredients based on said measured quantity of water, said modifying including determining a top up water quantity corresponding to a difference between the total quantity of water of the recipe and the measured quantity of water; and upon determining that the direction is a mixing direction, generating a loading instruction indicative that the concrete ingredients can be loaded into the drum, the loading instruction including adding only the top up water quantity into the drum.

[0018] Further in accordance with the second aspect of the present disclosure, said measuring the quantity of water can for example include determining a first position at which the water detector enters into water and a second position at which the water detector exits water, and determining the quantity of water based on the first and second positions.

[0019] Still further in accordance with the second aspect of the present disclosure, said water detector can for example include an interface exposed within the drum, the interface moving in back-and-forth sequences and experiencing a resistance to movement imparted by an immediate surrounding of the interface. [0020] Still further in accordance with the second aspect of the present disclosure, said measuring can for example include measuring a plurality of resistance response values indicative of said resistance to movement over at least a rotation of the drum, identifying first and second positions at which the resistance responses values cross a given threshold, and determining the quantity of water based on the first and second positions.

[0021] Still further in accordance with the second aspect of the present disclosure, the water detector can for example include an electromechanical actuator having the interface, the interface moving upon actuation of the electromechanical actuator with an electrical signal.

[0022] Still further in accordance with the second aspect of the present disclosure, the electrical signal can for example have a single frequency ranging between about 200 and 1,000 Hz, preferably between about 500 and 700 Hz and most preferably at about 650 Hz.

[0023] All technical implementation details and advantages described with respect to a particular aspect of the present disclosure are self-evidently mutatis mutandis applicable for all other aspects of the present disclosure.

[0024] Many further features and combinations thereof concerning the present improvements will appear to those skilled in the art following a reading of the instant disclosure.

DESCRIPTION OF THE FIGURES

[0025] In the figures,

[0026] Fig. 1 is a schematic view of an example of a system for loading concrete ingredients into a drum of a concrete mixer truck, shown with a water detector and a controller, in accordance with one or more embodiments;

[0027] Fig. 2 is a sectional view of the drum of Fig. 1, taken along section 2-2 of Fig. 1, in accordance with one or more embodiments;

[0028] Fig. 3 is a flow chart of a first example of a method of loading concrete ingredients into a drum of a concrete mixer truck, in accordance with one or more embodiments; [0029] Fig. 4 is a schematic view of an example of a water detector provided in the form of an electromechanical probe, in accordance with one or more embodiments;

[0030] Fig. 4A is a graph showing amplitude levels of the electromechanical probe of Fig. 4 at different temperatures, in accordance with one or more embodiments;

[0031] Fig. 5 is a graph showing a rotation signal and a detection signal as the drum rotates over a number of rotations, in accordance with one or more embodiments;

[0032] Fig. 6 is a flow chart of a second example of a method of loading concrete ingredients into a drum of a concrete mixer truck, in accordance with one or more embodiments;

[0033] Fig. 7 is a graph showing a detection signal over a number of drum rotations for a rotating drum having an unknown quantity of water in the drum, in accordance with one or more embodiments;

[0034] Fig. 8 includes graphs showing detection signals for a rotating drum having different quantities of water therein, in accordance with one or more embodiments;

[0035] Fig. 9 is a graph showing a measured quantity of water as a function of an angle defined between a first circumferential position at which the water detector enters water and a second circumferential position at which the water detector exits water, in accordance with one or more embodiments; and

[0036] Fig. 10 is a schematic view of an example of a computing device of an exemplary controller, in accordance with one or more embodiments.

DETAILED DESCRIPTION

[0037] Fig. 1 shows an example of a fresh concrete mixer truck 10 (hereinafter referred to as “the mixer truck 10”) for handling fresh concrete 12. As shown, the mixer truck 10 has a truck frame 14 and a rotating drum 16 which is rotatably mounted to the truck frame 14. As such, the drum 16 can be rotated about a rotation axis 18 which is at least partially horizontally-oriented relative to the vertical 20. [0038] Loading of a new recipe of concrete ingredients can be performed at a concrete production plant. Typically, the mixer truck moves into a loading location which vertically aligns a feed hopper 21 located above an opening of the drum 16 to a concrete ingredient chute of the concrete production plant. The loading of the concrete ingredients can be initiated following reception of a loading instruction incoming from the mixer truck 10. For instance, when it is determined that the mixer truck is ready to receive the concrete ingredients of a new recipe, the loading instruction can be generated and communicated to the concrete production plant, which can then proceed with the loading.

[0039] As illustrated, the drum 16 has inwardly protruding blades 22 mounted inside the drum 16 which, when the drum 16 is rotated in a mixing direction, keep the concrete ingredients and mixed them to one another. In contrast, when the drum 16 is rotated in an unloading direction, opposite to the mixing direction, the fresh concrete resulting from proper mixing of the concrete ingredients is forced along a discharge direction 24 towards a discharge outlet 26 of the drum 16 so as to be discharged at a job site, for instance.

[0040] To completely unload fresh concrete, the drum 16 is generally rotated in the unloading direction for a predetermined number of rotations. Depending on the quantity of the recipe, the predetermined number of rotations in the unloading direction can differ from one embodiment to another Tn some embodiments, even if the drum content is deemed to have been fully discharged, water may remain inside the drum 16 after the predetermined number of rotations. Alternately or alternatively, water may be added during the washing of the drum 16. In these situations, if a new recipe of concrete ingredients is loaded into the drum 16 while water remains inside, the intended recipe may have an excess of water which can lead to adverse effects to the properties of the concrete. Accordingly, it is preferable to load a new recipe of concrete ingredients into a dry drum rather than in a wet drum. Moreover, it was found preferable to load a new recipe of concrete ingredients into the drum as it rotates in the mixing direction as inconveniences can stem from doing otherwise. For instance, if the concrete ingredients are loaded into the drum 16 while it is not rotating, the concrete ingredients may not be properly mixed which can lead to an uneven or premature hardening of the fresh concrete. Furthermore, if the drum 16 is rotated in the unloading direction, then concrete ingredients may be expelled out of the drum 16 at the concrete production plant, which is undesirable.

[0041] As depicted, the mixer truck 10 can be provided with a system 100 for loading concrete ingredients into the drum 16 of the mixer truck 10. As depicted, the system 100 has a water detector 102 which is mounted to an inside wall of the drum 16. The water detector 102 is configured for performing one or more water measurements during at least one rotation of the drum 16. The water measurements generally includes at least a water measurement made at a bottom of the drum during a rotation thereof. More specifically, many water measurements are performed during each rotation of the drum 16. As best shown in Fig. 2, the water measurements can be performed at different circumferential positions of the water detector 102 including, but not limited, at circumferential positions corresponding to 90°, 180°, 270° and 360°, with the circumferential positions 90° and 270° extending along a horizontal plane. In some embodiments, the water measurements are performed at a given frequency as the drum 16 rotates. Accordingly, the number of water measurements during a single rotation of the drum 16 can vary as a function of the rotation speed of the drum 16. In some other embodiments, the water measurements can be performed at predetermined circumferential positions. In these latter embodiments, the number of water measurements during a single rotation of the drum 16 can remain constant regardless of the speed of rotation of the drum 16. It is generally preferred to perform water measurements at a constant frequency as the drum 16 rotates. In this way, water measurements are performed in an evenly distributed manner around the circumference of the drum 16 as it rotates. It is noted that performing water measurements at arbitrary moments as the drum 16 rotates can also be envisaged. In some other embodiments, the water measurements are more frequent within a lower hemisphere of the drum 16, i.e., at circumferential positions ranging from 90° to 270°, preferably at circumferential positions ranging from 135° to 225°, where water is more likely to be present.

[0042] The system 100 also has a controller 108 which is communicatively coupled to the water detector 102. The controller 108 has a processor and a non-transitory memory having stored thereon instructions that when executed by the processor perform one or more preprogrammed steps. The controller 108 is configured for receiving a rotation signal indicative of at least a direction of rotation of the drum 16. The rotation signal can indicate if the drum 16 is currently immobile, rotating in the unloading direction or rotating in the mixing direction. In some embodiments, the rotation signal can include a rotational speed of the drum 16. The rotation signal can originate from a rotation sensor which is mounted to the drum 16, to the truck frame 14, to a hydraulic system driving rotation of the drum 16, or a combination thereof. The rotation sensor can be provided in the form of a rheological probe, an electromechanical probe and the like. In some other embodiments, the rotation signal can originate from a user interface activatable by a driver in a cabin of the mixer truck, for instance. Accordingly, the rotation signal can be based on one or more measurements made on-truck or rather based on a visual inspection by the driver, for instance. In some embodiments, the mixer truck 10 is equipped with a speed control apparatus capable of controlling the rotation speed of the drum at all times. In these embodiments, the rotation signal can originate from a control signal of the speed control apparatus. External detectors monitoring the rotation speed of the drum 16 from a remote position can also be used in some embodiments.

[0043] The controller 108 is configured for generating a loading instruction indicative that the concrete ingredients can be loaded into the drum 16, i.e., that the drum 16 is ready for loading, when it is determined that the direction is a mixing direction and that the water measurements are indicative of dryness. It is intended that these two conditions must be met for the generating of the loading instruction. For instance, if the drum 16 is deemed to be dry but rotates in the unloading direction, no loading instruction is generated. If the drum 16 is deemed to be wet but it rotates in the mixing direction, no loading instruction is generated. Of course, if the drum 16 is deemed to be wet and it rotates in the unloading direction, no loading instruction is generated.

[0044] In some embodiments, the loading instruction triggers a visual indicator, an auditory indicator, a haptic indicator or a combination thereof. The visual, auditory or haptic indicator(s) can provide an external signaling to a concrete production plant. In these embodiments, the external signaling indicates that the mixer truck is ready to be loaded with a new recipe of concrete ingredients. In some embodiments, the loading instruction can be stored on an accessible computer-readable memory or transmitted to an external network such as the Internet or an intranet, for instance. In these embodiments, the concrete production plant can retrieve the stored loading instruction or received the transmitted loading instruction, and then proceed with the loading.

[0045] Fig. 3 shows a flow chart of an example method 300 of loading concrete ingredients into the drum 16 of the mixer truck 10. Although references to the reference numerals of the mixer truck 10 of Fig. 1 are made, the method 300 can be applied to other embodiments.

[0046] At step 302, the concrete mixer truck is moved into a loading location. The loading location can pertain to a concrete production plant. In some embodiments, the step of moving the concrete mixer truck into the loading location includes moving an opening of the drum below a concrete ingredient chute. The opening can be provided with a feed hopper facilitating the loading of the concrete ingredients into the drum.

[0047] At step 304, the drum is rotated into the mixing direction. In some embodiments, the drum can be rotated at low rotation speeds including, but not limited to, rotation speeds below 10 rotations per minute, preferably below 5 rotations per minute, and most preferably below 3 rotates per minute.

[0048] At step 306, the water detector 102 performs at least a water measurement at a bottom of the drum during at least one rotation thereof. In some embodiments, the water measurement is conveyed via a detection signal indicating whether or not water is detected in the drum. The detection signal can have an amplitude value varying as a function of time. In some embodiments, the detection signal indicates what material (e.g., fresh concrete, water, air) is exposed to the water detector 102. In these embodiments, dryness is detected when the detection signal indicates that air is in contact with the water detector 102 as the drum rotates. Wetness can be detected when the detection signal indicates that water is in contact with the water detector 102 as the drum rotates. In some embodiments, the water detector 102 can be a humidity detector.

[0049] At step 308, upon determining that the water measurement made at the bottom of the drum is indicative of dryness, the concrete ingredients of a new recipe are loaded into the drum. The concrete ingredients can be loaded all at once in the drum in some embodiments. In some other embodiments, the dry ingredients can be loaded in a first batch whereas the liquid ingredients can be loaded in a second batch. Ways to load the concrete ingredients into the drum can differ from one concrete production plant to another.

[0050] At step 310, the rotation speed of the drum is increased to a rotation speed above a rotation speed threshold for a given number of rotations. The increase in rotation speed can be performed following the generation of a mixing instruction indicating that the rotation speed of the drum should be increased above the rotation speed threshold. The rotation speed threshold can be at least 10 rotations per minute, at least 12 rotations per minute and more preferably at least 15 rotations per minute. In some embodiments, it is preferable to keep the mixer truck immobile when the rotation speed of the drum exceeds the rotation speed threshold to avoid fresh concrete being spilled out of the drum’s opening. Once the number of rotations required for mixing have been performed, the rotation speed of the drum can be reduced to rotations speeds lower than the rotation speed threshold. The lower rotation speed can be maintained for agitating the fresh concrete while the mixer truck moves to a job site. In some embodiments, either one or both of the steps 302 and 310 can be omitted.

[0051] In some embodiments, the water detector can be provided in the form of an electromechanical probe 104 such as the one shown in Fig. 4. Broadly described, the electromechanical probe 104 typically has an electromechanical actuator 120 having a frame 112 mounted to an inside wall 118a of the drum 16 and a moving element 116 actuatably mounted to the frame 112. The moving element 116 has an exterior interface 118b exposed within the drum 16 and to the fresh concrete 12 and which experiences a resistance to movement within the drum 16 upon actuation of the electromechanical actuator 120 with an electrical signal. As depicted, the electrical signal can be generated by a signal generator 142 powered by a power source 144 and controlled via the controller 108. In some embodiments, the electromechanical actuator 120 can include an accelerometer 134 which is mounted to the inside wall 118a and which moves in reaction to the actuation of the electromechanical actuator 120 and return force imparted by the fresh concrete 12, if any. In some embodiments, the movement of the accelerometer 134 over time can be transmitted to the controller 108 via a pair of communication units 136 and 140. Such communication can be wired, wireless or a combination of both. In these embodiments, each measurement can lead to a detection signal indicative of the resistance to movement experienced by the exterior interface 118b at a precise moment in time. The electrical signal used to excite the electromechanical actuator 120 can be an oscillatory signal having a single frequency for a given period of time, multiple frequencies generated each having respective periods of time following each other, a sweep of frequencies or a plurality of simultaneous frequencies. Applying the oscillatory signal to the electromechanical actuator 120 can cause the exterior interface 118b to vibrate a corresponding frequency. The frequency can range between about 200 and 1,000 Hz, preferably between about 500 and 700 Hz and most preferably is about 650 Hz. In some specific embodiments, the frequency at which the exterior interface is vibrated is 650 Hz and the oscillation is maintained for about at least 15 seconds, preferably at least 1 minute and most preferably at least 2 minutes.

[0052] In such embodiments, the water detector can generate a detection signal having an amplitude varying over time (or over drum rotations), with the amplitude varying depending on which material (e.g., fresh concrete 12, water, air) is exposed to the exterior interface 118b of the electromechanical probe 104. For instance, the detection signal can be generated by an accelerometer 134 being mechanically coupled to the inside wall 118a or the moving element 116. The amplitude can thereby denotes the position, speed and/or acceleration along an orientation perpendicular to the inside wall 118a. The more free the exterior interface 118b is to movement, the more the amplitude of the detection signal. It is noted that the stiffer the material exposed to the exterior interface 118b, the stronger the resistance to movement and thus the lower the amplitude. Accordingly, lower amplitude levels can be indicative of fresh concrete, greater amplitude levels can be indicative of dryness or air and amplitude levels ranging inbetween can be indicative of water or wetness. For instance, presence of fresh concrete can be determined when the amplitude of the detection signal is below a water-concrete interface threshold T _wa ter-concrete; presence of water, or wetness, can be determined when the amplitude is above the water-concrete interface threshold Twater-concrete and below a air-water interface threshold Tair-water; and presence of air, or dryness, can be determined when the amplitude of the detection signal is above the air-water interface threshold Tair-water. Accordingly, determining that the water measurements are indicative of dryness can include determining that a detection signal has one or more amplitude values being lower than a first amplitude threshold, greater than a second amplitude threshold, or a combination of both, throughout all or some of the measurements. An example of such an electromechanical probe is described in International Patent Publication No. WO 2021/178278, the contents of which are hereby incorporated by reference. It is generally preferred to provide the water detector with a reduced footprint having its detecting element being as close as the inner wall of the drum as possible, which can in turn allow detection of shallower volumes of water.

[0053] Fig. 4A is a graph showing amplitude levels of the electromechanical probe at different temperatures. As depicted, the temperature influences the frequency at which maximal amplitude variations occur. As maximal amplitude variations are desirable, for resolution and consistency purposes for instance, it was found that selecting an electrical signal with an optimal frequency can provide better measurements. For instance, Fig. 4A shows that at a temperature of about 4°C, the optimal frequency can be about 625 Hz; a temperature of about 12°C, the optimal frequency can be about 595 Hz; at a temperature of about 24°C, the optimal frequency can be about 525 Hz, and so forth. Accordingly, in some embodiments, the system is provided with a temperature sensor performing one or more temperature measurements within the drum. Then, the controller can operate the electromechanical probe based on the temperature measurements. More specifically, the electromechanical probe can be actuated with an electrical signal having a frequency selected based on the sensed temperature, e.g., a frequency that has been identified as optimal based on calibration data such as the one shown in Fig. 4 A. The calibration data can be provided in the form of a graph, look-up table, and mathematical equations, to name a few examples.

[0054] Reference is now made to Fig. 5 which shows the evolution of the rotation signal and of the rotation signal during a typical unloading/loading sequence. As depicted, the upper graph shows an example of the rotation signal as a function of time and the lower graph shows an example of the detection signal as a function of time. In this embodiment, the detection signal has an amplitude which varies inversely proportionally with the stiffness of the material exposed to the water detector. In this embodiment, when the amplitude of the detection signal is below a water-concrete interface threshold T _wa ter-concrete, the water detector is deemed to be exposed to concrete, when the amplitude of the detection signal is above the water-concrete interface threshold T _wa ter-concrete and below a air- water interface threshold T _air.wate r, the water detector is deemed to be exposed to water and when the amplitude is above the air-water interface threshold T air-water, the water detector is deemed to be exposed to air. A typical unloading operation requires the drum to be rotated into the unloading direction for a number of rotations. During these rotations, the amount of fresh concrete decreases gradually until the drum is left without any fresh concrete. Even if the fresh concrete has been fully unloaded after rotation A, as shown by amplitude levels being above the water-concrete interface threshold T _wate r-concrete interface threshold after rotation A, water can remain at the bottom of the drum as shown at rotations B and C. Accordingly, in this example, even if the amplitude of the detection signal shows that the drum is dry, i.e., the water detector is exposed to air only, it is only when the direction of the drum is switched from the unloading direction to the mixing direction that the loading instruction can be generated. The loading instruction can be generated instantly or generated at a delayed moment in time, for instance when it is deemed that the mixer truck is into a loading location of a concrete production plant.

[0055] In some specific embodiments, the water detector can be provided in the form of a rheological probe such as the one described in U.S. Patent Serial No. 9,199,391 B2, the contents of which are hereby incorporated by reference. In these embodiments, and due to the radially elongated shape of the rheological probe, and the distal positioning of the strain gauge, the rheological probe may be best suited for detecting bigger volumes of water rather than lower volumes of water. In embodiments where the water detector is provided in the form of a rheological probe, the detection signal has an amplitude indicating a pressure exerted by a surrounding material onto the distal end of the probe. Accordingly, greater amplitude levels can be indicative of fresh concrete, lower amplitude levels can be indicative of dryness or air and amplitude level ranging between the lower amplitude levels and the greater amplitude levels between can be indicative of water or wetness. In some other embodiments, the water detector is a binary water detector generating a signal carrying a first binary value (e.g., 0) when it is not exposed to water or carrying a second binary value (e.g., 1) when it is exposed to water. In some embodiments, the water detector includes one or more capacitive detection cells, one or more acoustic detection cells, one or more strain gauge detection cells, one or more proximity switches, and the like. However, it is understood that the water detector can be any suitable type of water detector.

[0056] Fig. 6 shows a flow chart of a second method 600 of loading a recipe of concrete ingredients into the drum 16 of the mixer truck 10. In this method, it is noted that the recipe includes at least a total quantity of water Q _to t. Although references to the reference numerals of the mixer truck 10 of Fig. 1 are made, the method 600 can be applied to other embodiments.

[0057] At step 602, the mixer truck is moved into a loading location. The loading location can pertain to a concrete production plant. In some embodiments, the step of moving the concrete mixer truck into the loading location includes moving an opening of the drum below a concrete ingredient chute. The opening can be provided with a feed hopper facilitating the loading of the concrete ingredients into the drum.

[0058] At step 604, the drum is rotated into a mixing direction. In some embodiments, the drum can be rotated at low rotation speeds including, but not limited to, rotation speeds below 10 rotations per minute, preferably below 5 rotations per minute, and most preferably below 3 rotates per minute.

[0059] At step 606, as the drum rotates, a quantity of water Ordaining remaining at a bottom of the drum is measured using a water detector. The water detector is preferably of the type allowing the quantity of water to be measured with a satisfactory precision. Preferably, the water detector is configured to detect entry in water and exit from water in some embodiments. For instance, the water detector can be an electromechanical probe or a proximity switch such as the ones described above. In some embodiments, the step 606 includes a step of determining a first position at which the water detector enters into water and a second position at which the water detector exits water, and a subsequent step of determining the quantity of water based on the first and second positions. If for instance the first and second positions show that the water detector spends at least X % of the time within water within a single rotation of the drum, then it can be determined that the quantity of water remaining within the drum is Y % of the total capacity of the drum. Knowing the total capacity of the drum thus allows to determine the quantity of water remaining into the drum. [0060] At step 608, the recipe of concrete ingredients is modified based on the measured quantity of water Qremaining remaining within the drum. More specifically, the step 608 includes a step of determining a top up water quantity Qtopup. Determination of the top up water quantity can be made by subtracting the measured quantity of water Qmmaining from the total quantity of water Qtot of the original recipe, i.e., Qtopup ⁼ Qtoc Qremaining.

[0061] At step 610, the modified recipe of concrete ingredients is loaded into the drum. The step 610 includes a step of adding only the top up water quantity Qtopup into the drum. In further, optional steps, the method 600 can include a step of increasing a rotation speed of the drum above a rotation speed threshold for a given number of rotations to thoroughly mix the concrete ingredients within the drum. The concrete ingredients can be loaded all at once in the drum in some embodiments. In some other embodiments, the dry ingredients can be loaded in a first batch whereas the liquid ingredients, including the top up water quantity Qtopup, can be loaded in a second batch, or vice versa.

[0062] It is understood that the method 600 can be performed by a system 100’ that may partially or wholly correspond to the system 100 described above. The system 100’ can have a water detector mounted inside the drum. The water detector is generally configured for measuring a quantity of water remaining at a bottom of the drum as the drum rotates. The system 100’ has a controller which is communicatively coupled to the water detector. The controller has a processor and a memory having stored thereon instructions that when executed by the processor perform the steps of: receiving a rotation signal indicative of a direction of the drum. As discussed above, the rotation signal can originate from an on-truck measurement or from a user interface with which the driver can interact. The controller can modify the recipe of concrete ingredients based on the measured quantity of water. The modification step can include a step of a top up water quantity corresponding to a difference between the total quantity of water of the recipe and the measured quantity of water. As such, upon determining that the direction is a mixing direction from the rotation signal, the controller can generate a loading instruction indicative that the concrete ingredients can be loaded into the drum. The loading instruction generally carry an instruction indicative that only the top up water quantity should be added into the drum. Tn this way, water excess can be avoided even in situations where water remains at a bottom of the drum from a previous recipe.

[0063] Fig. 7 shows a graph of a detection signal generated by a water detector for a drum having a given quantities of water therein for different drum rotations. More specifically, the detection signal shows four consecutive rotations of the drum. It was found that it is possible to determine the total amount of time required for a full rotation of the drum by identifying two similar patterned events in the detector signals. For instance, the time required for a full rotation can be determined by identifying a first moment in time where the amplitude goes below the airwater interface threshold Tair-water in a first rotation of the drum and a second moment in time where the amplitude goes below the air-water interface threshold T _a ir-water in a subsequent, second rotation of the drum. The difference in time between the first and second moments in time can thus indicate the rotation speed of the time. Moreover, by calculating the amount of time the amplitude is below the air- water interface threshold T _a ir-water compared to the amount of time the amplitude is above the air-water interface threshold Tair-water within a single rotation of the drum can be indicative of the total quantity of water within the drum. It is noted that by identifying a first circumferential position at which the water detector enters the water and a second circumferential position at which the water detector exits the water, one can determine the quantity of water based on the first and second circumferential positions and on a known geometry of the drum. It is noted that it is generally preferred to have a water detector that can have a given sensitivity so as to show variation in the detector signal when the water detector enters or exits water. In some embodiments, the water detector is provided in the form of an electromechanical probe such as the one described above.

[0064] Fig. 8 shows graphs of different detection signals generated by a water detector for a drum having different quantities of water therein while the drum rotates at 4 RPM. More specifically, from top to bottom, the detection signals correspond to known quantities of water corresponding to 0 gallon, 1 gallon, 4 gallons, 8 gallons, and 11.5 gallons. With such calibration data, it was found that a calibration curve can be determined. An example of such a calibration curve is shown in Fig. 9. As shown, the graph plots known quantities of water as a function of the difference between the first and second circumferential positions, i.e., the angle between the first circumferential position where the water detector enters the water and the second circumferential position where the water exits the water. Although a calibration curve is shown in this figure, it is noted that calibration data can be provided in some other equivalent forms including, but not limited to, a look up table, a mathematical equation and the like. As such, by determining a quantity of water remaining at a bottom of the drum after a recipe of fresh concrete has been unloaded at a job site, one can modify the quantity of water to be added in a subsequent recipe of fresh concrete. By doing so, a situation where a recipe of concrete ingredients having too much water can be avoided. Steps of manually inspecting the drum for water excess or removing the excess water out of the drum are also avoided.

[0065] It is noted that in some embodiments, truck drivers are required to wash the drum after a discharge at a job site. In some jurisdictions, the drum must be washed with a minimal quantity of water, e.g., with at least 50 gallons of water. In these embodiments, the water detector can be used to monitor the quantity of water added into the drum for washing purposes. In these embodiments, the water detector is configured to measure the quantity of water currently received within the drum. In some embodiments, the number of rotations of the drum while it is filled with the minimal quantity of water can be monitored as well. In these latter embodiments, washing of the drum may be deemed to be done only when a given number of rotations in the mixing direction have been made while the drum contains the minimal amount of water. In these embodiments, the controller may be configured to generate an alert when it is determined that the drum has been washed with a quantity of water being less than the minimal amount of water. The alert can be generated in real time, stored into an accessible memory system or communicated to an external network.

[0066] The controller 108 illustrated at Figs. 1,2 and 3 can be provided as a combination of hardware and software components. The hardware components can be implemented in the form of a computing device 1000, an example of which is described with reference to Fig. 10. The software components can be packaged into a computer program which receives information and process it as programmed.

[0067] Referring to Fig. 10, the computing device 1000 can have a processor 1002, a memory 1004, and I/O interface 1006. Instructions 1008 for performing a method of loading concrete ingredients into a drum can be stored on the memory 1004 and accessible by the processor 1002 for execution.

[0068] The processor 1002 can be, for example, a general -purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, a programmable read-only memory (PROM), or any combination thereof.

[0069] The memory 1004 can include a suitable combination of any type of computer-readable memory that is located either internally or externally such as, for example, random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically-erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM) or the like.

[0070] Each VO interface 1006 enables the computing device 1000 to interconnect with one or more input devices, such as a water detector, a rotation detector, a user interface, or with one or more output devices such as a visual indicator, or any other communication module.

[0071] Each I/O interface 1006 enables the controller 108 to communicate with other components, to exchange data with other components, to access and connect to network resources, to server applications, and perform other computing applications by connecting to a network (or multiple networks) capable of carrying data including the Internet, Ethernet, plain old telephone service (POTS) line, public switch telephone network (PSTN), integrated services digital network (ISDN), digital subscriber line (DSL), coaxial cable, fiber optics, satellite, mobile, wireless (e.g. Wi-Fi, WiMAX), SS7 signaling network, fixed line, local area network, wide area network, and others, including any combination of these.

[0072] The software application is configured to receive information from the water detector, the rotation sensor and the like and to determine instructions to be processed by the processor or transmitted to an external application. In some embodiments, the software application is stored on the memory 1004 and accessible by the processor 1002 of the computing device 1000. More specifically, the software application receives a rotation signal indicative of a direction of the drum, and upon determining that the direction is a mixing direction and that the water measurements are all indicative of dryness, generates a loading instruction indicative that the concrete ingredients can be loaded into the drum. If the rotation signal indicates an unloading direction, and/or if one of the water measurements are indicative of wetness, an alert can be generated to prevent a new recipe of concrete ingredients to be loaded into the drum.

[0073] The computing device 1000 and the software application described above are meant to be examples only. Other suitable embodiments of the controller can also be provided, as it will be apparent to the skilled reader. [0074] As can be understood, the examples described above and illustrated are intended to be exemplary only. For instance, the water detector can be provided in the form of any type of water detector. In some embodiments, the water detector can be provided in the form of a camera looking inside the drum as it rotates. The scope is indicated by the appended claims.