A method for detecting a charge level in a blast hole

Abstract

The application discloses a kind of borehole material level detection methods, it is related to the field of blasting filling, including steps: obtaining the current material target filling depth of target borehole stage;Unwind the reel and make the material level switch drop to the target measurement position corresponding to the material target filling depth;Judge whether filling material reaches the target measurement position;If filling material does not reach the target measurement position, then continue to fill and detect;If filling material reaches the target measurement position, then judge whether there is a next filling stage;If there is a next filling stage, then update the material target filling depth of next filling stage of target borehole to the material target filling depth of current filling stage, and repeat the above steps, if there is no next filling stage, then the filling of target borehole is filled.The method provided by the application has high real-time detection performance for filling material level measurement, and realizes the automatic filling of borehole in open pit mine.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of blasting filling, in particular, to a method for detecting the filling level in a blast hole. BACKGROUND

[0002] In the process of open-pit mining blasting, charging operation is an essential link. The granular explosive is filled into the blast hole to complete the charging operation, and then the blast hole is blocked for blasting.

[0003] At present, when the blast hole in the open-pit mine has a small diameter, the conventional non-contact level measurement instrument such as ultrasonic level meter or radar level meter is easy to cause the sound wave or electromagnetic wave to touch the hole wall during the test, resulting in inaccurate measurement of the filling level, which is difficult to meet the requirement of filling level detection in the blast hole with a small diameter. When the material is filled into the blast hole in the open-pit mine, a large amount of dust is generated, and the measurement method based on laser and machine vision is easy to be disturbed by dust, which basically cannot meet the requirement of filling level measurement in the blast hole in the open-pit mine. The traditional contact level measurement instrument such as resistance spin type level meter or heavy hammer type level meter has a long single test time, which leads to low test efficiency and cannot meet the requirement of rapid construction in the open-pit mine. The traditional manual measurement method for the blast hole also has the disadvantages of large measurement error and repeatability error, and long measurement time, which cannot adapt to large-scale industrial production. In summary, the existing technology cannot effectively detect and control the filling depth of granular explosive according to the actual situation on site, which leads to that the granular explosive cannot be filled to the specified depth in the blast hole, and the granular explosive is easy to be filled too much or too little. If the filling amount of granular explosive is large, the explosive is easy to be wasted, and uncontrollable explosion accidents are easy to occur. If the filling amount of granular explosive is small, it is not conducive to the blasting work.

[0004] Therefore, in view of the above problems, it is necessary to provide a method for detecting the filling level in a blast hole for filling explosive in the blast hole of the open-pit mine, so as to effectively detect the filling depth of the explosive, and further solve or at least partially solve the above technical problems. SUMMARY

[0005] The method for detecting the filling level in a blast hole provided by the present application solves the technical problem that the existing open-pit mine is difficult to effectively detect the filling depth of explosive in the blast hole.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] The application discloses a method for detecting a material level in a blast hole, and belongs to the technical field of material level detection.

[0008] The method comprises the following steps:

[0009] S10, obtaining a target filling depth of material in a current charging stage of a target blast hole;

[0010] S20, unwinding the winding disc to lower the material level switch to a target measuring position corresponding to the target filling depth of material;

[0011] S30, feeding filling material into the target blast hole through the material conveying pipeline, and performing real-time material level detection by using the material level switch to determine whether the filling material reaches the target measuring position;

[0012] S41, if the filling material does not reach the target measuring position, continuously charging and detecting;

[0013] S42, if the filling material reaches the target measuring position, determining whether there is a next charging stage;

[0014] S431, if there is a next charging stage, updating a target filling depth of material in the next charging stage of the target blast hole to the target filling depth of material in the current charging stage, and entering steps S10 to S42;

[0015] S432, if there is no next charging stage, ending the charging of the target blast hole.

[0016] Further, in step S30, the determination of whether the filling material reaches the target measuring position comprises the following steps:

[0017] S31, determining whether a material level arrival signal sent by the material level switch is received, wherein if the filling material wraps the material level switch, the material level switch sends the material level arrival signal;

[0018] S321, if the material level arrival signal is received, unwinding the winding disc to lower the material level switch by a preset length;

[0019] S322, if the material level arrival signal is not received, continuously detecting until the material level arrival signal is detected;

[0020] S33, after a preset time interval, rewind the winding reel to raise the material level switch by a preset length, and at the same time, obtain the winding tension value when the material level switch rises.

[0021] S34, if the winding tension value is not less than the effective tension threshold, then it is determined that the filling material has reached the target measurement position;

[0022] S35, if the winding tension value is less than the effective tension threshold, proceed to step S31.

[0023] Furthermore, in step S30, before conveying the filling material into the target borehole through the material conveying pipe, the following is also included:

[0024] According to the design ratio, the mixed explosive of ammonium nitrate and diesel is transported into the material conveying pipeline. The diesel ratio of the mixed explosive injected into the deeper holes is not less than that of the mixed explosive injected into the shallower holes.

[0025] Furthermore, the servo motor drives the winding reel to rotate around the central axis, thereby winding or unwinding the cable. One rotation of the winding reel is divided into P pulses corresponding to the servo motor, where P is a positive integer greater than 100.

[0026] Using formula Calculate the unwinding cable length at the nth unwinding turn, where... The diameter of the cable loop corresponding to the kth turn of unwinding;

[0027] Using formula Calculate the cable redundancy length from the nth turn to the (n+1)th turn, where, This is the diameter of the cable loop corresponding to the (k+1)th unwinding turn;

[0028] The length of the suspension cable is determined based on the elevation of the winding reel relative to the horizontal plane of the borehole.

[0029] The layout depth corresponding to the target measurement position is calculated by subtracting the unwinding cable length and the cable redundancy length from the total hole depth using the formula.

[0030] Furthermore, the level switch adopts a capacitive level detection switch.

[0031] The present invention has the following beneficial effects:

[0032] The hole filling level detection method provided by the application detects the filling level of the material in the hole in real time by hanging the filling level switch in the hole to the current target filling depth of the material, adopts a contact type filling level measurement mode, and has higher reliability and more accurate detection results compared with a non-contact type material level measurement instrument such as an ultrasonic filling level meter or a radar filling level meter, and a measurement instrument such as laser and machine vision. Meanwhile, when the filling material reaches the current target filling depth of the material, the next current target filling depth of the material of the target hole is automatically obtained, the next current target filling depth of the material is updated as the current target filling depth of the material, and the filling material in the next section is filled, so that the automatic filling of the hole in the open pit is realized.

[0033] In addition to the purposes, features and advantages described above, the application has other purposes, features and advantages. The application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, illustrate the preferred embodiments of the application, and assist in the explanation of the application. In the drawings:

[0035] Figure 1 is a structure diagram of a hole filling level detection system in a specific embodiment of the application;

[0036] Figure 2 is a flowchart of a hole filling level detection method in a specific embodiment of the application;

[0037] Figure 3 is Figure 2 a specific flowchart of judging whether the filling material reaches the target measurement position.

[0038] LEGEND

[0039] 100, hole filling level detection system; 10, material conveying pipeline; 20, force wheel frame; 30, filling level detection mechanism; 31, winding reel; 32, cable winding and unwinding line; 33, filling level switch. DETAILED DESCRIPTION

[0040] It should be understood that the specific embodiments described herein are only used to explain the application and do not limit the application.

[0041] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0042] It should be noted that all the direction indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the direction indications also change accordingly.

[0043] In addition, the descriptions of “first”, “second” and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as “first” and “second” can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0044] Please refer to Figure 1 and Figure 2 The present application provides a blast hole material level detection method, which is used for a blast hole material level detection system 100. The blast hole material level detection system 100 comprises a material conveying pipeline 10, a force applying wheel frame 20 and a material level detection mechanism 30. The material conveying pipeline 10 comprises a plug-in material guiding filling pipe and a material guiding pipe which is obliquely arranged on the plug-in material guiding filling pipe. The plug-in material guiding filling pipe is arranged vertically. The force applying wheel frame 20 is fixedly sleeved on the plug-in material guiding filling pipe and is below the material guiding pipe. The material level detection mechanism 30 comprises a winding reel 31, a cable winding and unwinding line 32 and a material level switch 33. The connecting end of the cable winding and unwinding line 32 is wound on the winding reel 31. The freedom degree of the cable winding and unwinding line 32 is connected with the material level switch 33. The material level switch 33 is arranged through the plug-in material guiding filling pipe from the top of the plug-in material guiding filling pipe.

[0045] The blast hole material level detection method comprises the following steps:

[0046] S10, obtaining a material target filling depth of a current material injection stage of a target blast hole;

[0047] S20, unwinding the winding reel to lower the material level switch to a target measurement position corresponding to the material target filling depth. S30, detecting the material level of the target blast hole according to the target measurement position.

[0048] S30, feeding the filling material into the target blast hole through the material conveying pipeline, and using the material level switch to check the material level in real time to determine whether the filling material reaches the target measurement position;

[0049] S41, if the filling material does not reach the target measurement position, continue to inject and detect;

[0050] S42, if the filling material reaches the target measurement position, determine whether there is a next injection stage;

[0051] S431, if there is a next injection stage, update the material target filling depth of the next injection stage of the target blast hole to the material target filling depth of the current injection stage, and enter steps S10 to S42;

[0052] S432, if there is no next injection stage, the injection filling of the target blast hole is completed.

[0053] The blast hole material level detection method provided by the present application detects the material level in real time when the material level switch is hung in the blast hole to the current material target filling depth during real-time filling, uses a contact type material level measurement method, and has higher reliability and more accurate detection results compared with non-contact material level measurement instruments such as ultrasonic material level meters or radar material level meters, and measurement instruments such as lasers and machine vision. At the same time, when the filling material reaches the current material target filling depth, the next current material target filling depth of the target blast hole is automatically obtained, the next current material target filling depth is updated to the current material target filling depth for the next section of filling injection, and the automatic filling of the blast hole in the open pit is realized.

[0054] It can be understood that when injecting material into the target blast hole, it can be divided into multiple working sections for step-by-step injection filling, and the material target filling depth is calculated based on the bottom of the target blast hole.

[0055] Please refer to Figure 3 Further, in step S30, determining whether the filling material reaches the target measurement position specifically includes the steps of:

[0056] S31, determining whether a material level signal sent by the material level switch is received, and if the filling material wraps the material level switch, the material level switch sends the material level signal;

[0057] S321, if the material level signal is received, the reel is unwound to lower the material level switch by a preset length;

[0058] S322, if the material level signal is not received, continue to detect until the material level signal is detected;

[0059] S33, after a preset time interval, winding the winding reel to make the material level switch rise by a preset length, and obtaining a winding tension value when the material level switch rises;

[0060] S34, if the winding tension value is not less than an effective tension threshold value, determining that the filling material reaches a target measurement position;

[0061] S35, if the winding tension value is less than the effective tension threshold value, entering step S31.

[0062] It can be understood that in the scheme of the present application, the preset time interval is set according to actual conditions, which can be 1 second, 2 seconds, 5 seconds or other time intervals, and the effective tension threshold value is set according to actual conditions.

[0063] Further, before the step S30, the filling material is transported into the target blast hole through the material conveying pipeline, further comprising:

[0064] According to the design ratio, the mixed explosive mixed by ammonium nitrate and diesel is transported into the material conveying pipeline, wherein the diesel ratio of the mixed explosive injected at a deeper hole depth is not less than the diesel ratio of the mixed explosive injected at a shallower hole depth.

[0065] Further, the winding and unwinding cable is wound or unwound by rotating the winding reel around the central axis by the servo motor, and one rotation of the winding reel is divided into P pulses corresponding to the servo motor, P is a positive integer greater than 100.

[0066] The unwinding cable length of the nth circle is calculated by the formula , wherein is the cable circle diameter corresponding to the kth circle;

[0067] The cable redundancy length from the nth circle to the nth+1 circle is calculated by the formula , wherein is the cable circle diameter corresponding to the k+1th circle;

[0068] The hanging cable length is determined according to the arrangement elevation of the winding reel relative to the horizontal plane of the blast hole.

[0069] The arrangement depth corresponding to the target measurement position is calculated by the formula total hole depth minus unwinding cable length and cable redundancy length.

[0070] In a specific embodiment of the present application, one turn of the winding disc is designed into 10000 pulse steps corresponding to the servo motor, and the winding mode is to stack one turn by one turn, the diameter of the innermost turn is 90mm, the outer diameter of the tensile cable (retractable cable) is 3.5mm, if the total number of winding turns is m, then the diameter of the cable coil corresponding to the kth turn when unwinding is is mm.

[0071] Further, the material level switch adopts a capacitive material level inspection detection switch. In the scheme of the present application, the controller of the capacitive material level inspection detection switch detects the presence or absence of material by measuring the change in the dielectric constant of the air in the material box, which causes a change in the capacitance. In order to detect these small changes, the sensor uses a detection circuit that can work at a relatively low frequency (6kHz). The capacitive detection principle is suitable for detecting the material level in the blast hole because it can overcome some unfavorable factors such as a large amount of dust in the blast hole and a fast airflow speed. Specifically, if the filling material wraps the material level switch, the material level switch sends the material level in place signal.

[0072] In the scheme of the present application, a capacitive material level inspection detection switch is used, which is more suitable for detecting the material level in the blast hole than an electrode type detection switch. The electrode type detection switch measures the high and low liquid levels by using the conductive properties of the material, and can also be used for weakly conductive liquids and damp solids. Since the material in the blast hole is a dry solid with low conductive properties, the electrode type measurement principle is not suitable for detecting the material level in the blast hole.

[0073] In the scheme of the present application, a resistance rotation type material level inspection detection switch is used, which is more suitable for detecting the material level in the blast hole than a resistance rotation type detection switch. The resistance rotation type vane is connected to the clutch through a transmission shaft. When the vane does not contact the material, the motor operates normally. When the vane contacts the material and causes resistance, the motor stops rotating, and an electrical contact signal is output to measure the material level height, and an indicator light can also be connected to display the state. Since the resistance rotation type requires the rotation of the resistance rotation vane, and the material conveying speed and conveying airflow in the blast hole are relatively fast, which may cause the resistance rotation vane to malfunction without fully contacting the material, therefore, the resistance rotation type measurement principle is also not suitable for detecting the material level in the blast hole.

[0074] In the scheme of the present application, the capacitive material level inspection detection switch is more suitable for detecting the material level in the blast hole than the tuning fork type detection switch, wherein the tuning fork type detection switch is designed by utilizing the damping effect of medium on the vibration of the tuning fork and the piezoelectric effect principle, the sensing part of the material level detection is composed of a tuning fork, which has a fixed vibration frequency and amplitude, when the tuning fork is subjected to the damping effect of the medium, the tuning fork stops vibrating, and the control circuit drives the relay to send a switch signal. The material in the blast hole is subjected to the vibration and amplitude of the tuning fork under the impact of high-speed airflow, which leads to the fact that the tuning fork type detection principle is also not suitable for detecting the material level in the blast hole.

[0075] In the scheme of the present application, the capacitive material level inspection detection switch is more suitable for detecting the material level in the blast hole than the photoelectric type detection switch, wherein when the sensor tip is in the air, the infrared light in the sensor tip will be reflected back to the transistor detector. When in a liquid state, the infrared light beam will be refracted out of the sensor tip, thereby reducing the energy reaching the detector, and realizing the detection of the presence or absence of material level. Since the dust in the blast hole is large, it greatly reduces the energy reaching the detector, and for the same reason, the photoelectric detection principle is not suitable for material detection in the blast hole.

[0076] In the scheme of the present application, the capacitive material level inspection detection switch is more suitable for detecting the material level in the blast hole than the ultrasonic type detection switch, wherein the ultrasonic type detection switch measures the horizontal position by calculating the duration and intensity of the high-frequency sound wave reflected from the liquid surface back to the sensor - the required time relative to the distance between the sensor and the liquid. Like the analysis of the ultrasonic principle under the penetration type, the ultrasonic detection principle under the non-contact type is also not suitable for material detection in the blast hole.

[0077] In the scheme of the present application, the capacitive material level inspection detection switch is more suitable for detecting the material level in the blast hole than the laser type detection switch, wherein a continuous or high-speed pulsed laser beam is emitted by a semiconductor laser, the laser beam is reflected when encountering the surface of the measured object, and the light returned is received by a laser receiver. And accurately record the time difference between the emission and reception of the laser, thereby determining the distance between the laser radar and the measured object. Since the dust in the blast hole is large, it greatly reduces the pulsed laser beam reflected from the surface of the material back to the laser receiver, resulting in a large laser measurement error; for the same reason, the laser detection principle is not suitable for material detection in the blast hole.

[0078] In this invention, a capacitive level detection switch is used, which is more suitable for detecting the material level inside a borehole compared to a radar-type detection switch. The radar-type detection switch utilizes the echo ranging principle; its horn-shaped or rod-shaped antenna emits microwaves towards the surface of the material being measured. When the microwaves propagate to material surfaces with different relative permittivity, they are reflected and received by the antenna. The time difference between the emitted and received waves is proportional to the distance between the material surface and the antenna; by measuring the propagation time, the distance can be determined. However, due to the large amount of dust inside the borehole, the echo energy reflected back to the radar antenna from the material surface is greatly reduced, resulting in a large measurement error for the radar-type switch. Similarly, the radar detection principle is not suitable for detecting materials inside boreholes.

[0079] In this invention, a capacitive level detection switch is used, which is more suitable for detecting the material level inside the borehole than a microwave detection switch. With a microwave detection switch, when microwave-absorbing material is present on the same plane as the receiver, the microwave beam cannot reach the receiver, and therefore the receiver cannot detect the microwave beam. When the receiver detects the microwave beam, a relay is triggered when the state changes. Because of the large amount of dust inside the borehole, the microwave beam may not reach the microwave receiver, ultimately leading to a large measurement error with microwave detection. Similarly, the microwave detection principle is not suitable for detecting materials inside the borehole.

[0080] Understandably, in the specific implementation of the borehole level detection method of the present invention, the system first needs to set the target measurement position of the target borehole level (target material filling depth) according to the actual situation. Then, the servo motor drives the cable winding and unwinding reel to send the level switch to the designated target measurement position and send a level measurement ready feedback signal. The control system automatically sets the rotation speed of the three discharge valves at the bottom of the material tank in advance according to the set target measurement position. The larger the borehole depth, the higher the discharge valve rotation speed is set; the smaller the borehole depth, the lower the discharge valve rotation speed is set. At the same time, the borehole depth setting can also affect the mixing ratio of ammonium nitrate and diesel. When the set borehole depth is larger, the system makes the diesel plunger pump rotate higher, resulting in a larger proportion of diesel in the material, and ultimately a larger explosion energy of the material. When the set borehole depth is smaller, the system makes the diesel plunger pump rotate lower, resulting in a smaller proportion of diesel in the material, and ultimately a smaller explosion energy of the material. Understandably, in the solution of the present invention, the depth of the injection hole is inversely proportional to the injection time.

[0081] In the scheme of the present application, the pneumatic conveying system is used for conveying the material and injecting the material into the target blast hole. When the pneumatic conveying system receives the feedback signal of the material level measurement being ready, it starts to convey the material to the target blast hole through the material conveying pipeline. When the material reaches the position of the material level switch and completely covers the probe of the material level switch, the material level switch automatically sends the material level reaching signal to the system. After receiving the material level reaching signal sent by the material level switch, the system automatically controls the servo motor to move downward by a small displacement and detects whether the tension received by the servo motor reaches the set effective tension threshold. If the effective tension threshold is reached, it is accurately judged that the material level switch is indeed surrounded by the material. If the effective tension threshold is not reached, the system will continue to add the material until the material level reaching signal is received and the effective tension threshold received by the servo motor reaches the set effective tension threshold, and then the system sends the material level measurement completion signal. After receiving the material level measurement completion signal, the system automatically drives the winding drum and the cable through the servo motor to quickly pull back the material level switch to the position near the winding drum to prepare for the next material level measurement.

[0082] The above merely describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for detecting material level inside a borehole, characterized in that, A borehole material level detection system is used, comprising a material conveying pipe, a force-applying wheel frame, and a material level detection mechanism. The material conveying pipe includes an insertion guide filling pipe and an inclined feed guide pipe mounted on the insertion guide filling pipe. The insertion guide filling pipe is arranged vertically. The force-applying wheel frame is fixedly sleeved on the insertion guide filling pipe and positioned below the feed guide pipe. The material level detection mechanism includes a reel, a take-up and undo cable, and a material level switch. The connecting end of the take-up and undo cable is wound around the reel, and the free degree of freedom of the take-up and undo cable is connected to the material level switch. The material level switch passes through the insertion guide filling pipe from the top. The method for detecting material level inside boreholes includes the following steps: S10, Obtain the target material filling depth of the target borehole at the current injection stage; S20, unwind the reel to lower the material level switch to the target measurement position corresponding to the target filling depth of the material; S30, filling material is conveyed into the target borehole through the material conveying pipeline, and a material level switch is used to check the material level in real time to determine whether the filling material has reached the target measurement position. Determining whether the filling material has reached the target measurement position specifically includes the following steps: S31, determine whether the material level signal sent by the material level switch is received; if the filling material covers the material level switch, the material level switch sends the material level signal. S321, if the material level signal is received, the winding reel is unwound to lower the material level switch by a preset length; S322, If no material level signal is received, continue to detect until the material level signal is detected; S33, after a preset time interval, the winding reel is wound up to raise the material level switch by a preset length, and at the same time, the winding tension value when the material level switch rises is obtained. S34, if the winding tension value is not less than the effective tension threshold, then it is determined that the filling material has reached the target measurement position; S35, if the winding tension value is less than the effective tension threshold, proceed to step S31; S41, if the filling material does not reach the target measurement position, continue filling and detection; S42, If the filling material reaches the target measurement position, determine whether there is a next injection stage; S431, if there is a next injection stage, update the target material filling depth of the next injection stage of the target borehole to the target material filling depth of the current injection stage, and proceed to steps S10 to S42. S432, if there is no next injection stage, the injection filling of the target borehole is completed.

2. The method for detecting material level inside a borehole according to claim 1, characterized in that, In step S30, before conveying the filling material into the target borehole through the material conveying pipe, the following steps are also included: According to the design ratio, the mixed explosive of ammonium nitrate and diesel is transported into the material conveying pipeline, wherein the diesel ratio of the mixed explosive injected at deeper holes is not less than the diesel ratio of the mixed explosive injected at shallower holes.

3. The method for detecting material level inside a borehole according to any one of claims 1 or 2, characterized in that, A servo motor drives a cable reel to rotate around its central axis, thereby winding or unwinding the cable. One rotation of the cable reel is divided into P pulses corresponding to the servo motor, where P is a positive integer greater than 100. Using formula Calculate the unwinding cable length at the nth unwinding turn, where... The diameter of the cable loop corresponding to the kth turn of unwinding; Using formula Calculate the cable redundancy length from the nth turn to the (n+1)th turn, where, This is the diameter of the cable loop corresponding to the (k+1)th unwinding turn; The length of the suspension cable is determined based on the elevation of the winding reel relative to the horizontal plane of the borehole. The layout depth corresponding to the target measurement position is calculated by subtracting the unwinding cable length and the cable redundancy length from the total hole depth using the formula.

4. The method for detecting material level inside a borehole according to any one of claims 1 or 2, characterized in that, The level switch is a capacitive level detection switch.

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