Test platform and method for simulating pipeline transportation of mine filling slurry

Abstract

The present invention discloses a test platform and method for simulating pipeline transportation of filling slurry in mines. The test platform includes a batching and stirring device and a pipeline system, and also includes a filling pump, a pipeline bracket, a buffer tank and a control system; the pipeline system includes a feed pipeline, a downpipe, a return pipe, a discharge pipe, an uppipe and a buffer return pipeline. The present invention can complete the L-tube gravity transportation test, the downward filling pumping test, the pumping ring pipe transportation test, etc., and can also realize the accurate calculation of viscosity coefficient, yield stress and gravity flow rate. The configuration mode is flexible and diverse, and can be consistent with the actual mine scene, which improves the accuracy of the simulation test, fills the gap in the current filling slurry pipeline transportation experiment, and provides a data basis for the design and operation of the underground filling pipe network in the mine, which has a guiding role.

Description

Technical Field

[0001] The invention relates to a test platform for simulating pipeline transportation of mine filling slurry, and also relates to a test method for simulating pipeline transportation of mine filling slurry. Background Art

[0002] Tailings filling technology is a new type of mine filling technology developed in the late 1980s and is increasingly widely used in mines. The characteristic of this technology is that tailings are used as filling aggregates, which are transported to the empty area of ​​underground stopes in a high concentration state through activation and mixing. This process can fill graded coarse tailings, graded fine tailings, or even all tailings as filling materials into the mine.

[0003] Pipeline transportation is one of the key processes for mine filling. It specifically includes transportation parameter design, pipe network layout optimization, and pumping equipment selection. The key to pipeline transportation design lies in the determination of the pipeline transportation resistance of the filling slurry. Affected by many factors such as material shape, particle size composition, concentration, ash-sand ratio, flow rate, pipe diameter, etc., many mines have been able to rely on experience for many years to judge whether the slurry can be transported by gravity in the pipeline (the reasonable filling and transportation multiple is 4-6, the transportable multiple is 7-9, the limit gravity filling multiple is 10, and the filling multiple exceeds 10. It is judged that it cannot be transported by gravity). This method is relatively general and not very applicable. It cannot fully guarantee the safety and reliability of the transportation process. For different slurries such as two-phase flow and structured flow, the error is large. This method may cause the mine conveying resistance to be overestimated, resulting in an overly conservative design and even increased investment in pumping equipment. It may also cause the conveying resistance to be underestimated, leading to unreasonable equipment selection, severe pipeline wear, pipe blockage, pipe breakage, slurry denaturation and other problems, and even cause large-scale pipe blockage accidents, low filling efficiency, high cost of handling pipeline silt and other production problems.

[0004] Currently, the designers are unable to use existing theories to make accurate calculations, and must use experiments to determine the areas and ranges that can be filled by gravity and the areas and ranges that can be filled by pumping, so as to meet the requirements of high-quality mine discovery.

[0005] In the prior art, most of the experimental devices for filling slurry pipeline transportation are single pipeline structures, either pumping ring pipe tests or L-tube gravity tests. Moreover, they are unable to simulate the situation where the mine filling multiple is high, gravity cannot be achieved, and downward pumping filling is required, resulting in the simulation test results not being able to reflect the actual situation of on-site production.

[0006] In addition, the existing simulation test method does not consider the impact of slurry density, concentration and temperature on resistance, resulting in deviations between the test results and the actual situation. Summary of the invention

[0007] The present invention proposes a test platform and method for simulating pipeline transportation of mine filling slurry, the purposes of which are: (1) to simulate various actual scenarios such as L-tube gravity transportation, pumped ring pipe transportation and downward filling pumping; (2) to conduct real-time and dynamic monitoring of the test, obtain the rheological characteristic values ​​during the transportation process, consider the influence of slurry density, concentration and temperature on resistance, eliminate the deviation of the original calculation method, and provide more accurate data support for actual mine production.

[0008] The technical solution of the present invention is as follows:

[0009] A test platform for simulating pipeline transportation of mine filling slurry, comprising a batching and stirring device and a pipeline system, wherein the batching and stirring device is installed on a lifting support mechanism;

[0010] The test platform also includes a filling pump, a pipeline support, a buffer tank and a control system;

[0011] The pipeline support is used to support the pipeline system and to adjust the height of the pipeline in the pipeline system;

[0012] The pipeline system includes a feed pipeline, a downflow pipeline, a reflux pipe, a discharge pipe, an upflow pipeline and a buffer return pipeline;

[0013] The batching and stirring device and the filling pump are connected to the feed end of the descending pipeline through the feed pipeline, and the discharge end of the descending pipeline is connected to the feed end of the ascending pipeline through the reflux pipe and is also connected to the feed end of the discharge pipe; the discharge end of the ascending pipeline is located above the batching and stirring device and is used to return the slurry to the batching and stirring device; the discharge pipe is used to send the slurry into the buffer tank; the discharge end of the buffer tank is connected to the feed end of the ascending pipeline through the feed pump and the buffer reflux pipeline in turn;

[0014] The pipeline system is equipped with a control valve and a detection device, wherein the detection device includes a flow meter, a pressure sensor and a temperature sensor; the control valve and the detection device are both electrically connected to the control system.

[0015] As a further improvement of the above test platform: the feed pipeline includes a first feed pipe and a second feed pipe;

[0016] One end of the first feed pipe is connected to the discharge end of the batching and stirring device, and the other end is connected to the feed end of the downward pipeline;

[0017] The discharge end of the batching and stirring device is also connected to the feed end of the downward pipeline through a filling pump and a second feed pipe in sequence;

[0018] The control valve includes a third switch valve arranged on the first feed pipe.

[0019] As a further improvement of the above test platform: the control valve includes a first switch valve arranged on the reflux pipe and a second switch valve arranged on the discharge pipe.

[0020] As a further improvement of the above test platform: the discharge pipe is also connected to a sewage pipe; the sewage pipe is used to discharge the slurry into the sedimentation tank, and a fourth switch valve is provided on the sewage pipe.

[0021] As a further improvement of the above-mentioned test platform: it also includes a clean water tank, a clean water pump and a clean water pipe. The clean water pipe is used to introduce the clean water in the clean water tank into the cache tank, and the clean water pump is installed on the clean water pipe.

[0022] As a further improvement of the above test platform: the descending pipeline includes a first vertical pipe, a first inclined pipe and a first horizontal pipe which are sequentially connected end to end in the direction from the batching and stirring device to the discharge pipe;

[0023] The upward pipeline includes a second horizontal pipe, a second inclined pipe, a second vertical pipe and a third horizontal pipe which are connected end to end in sequence from the reflux pipe to the batching and stirring device;

[0024] The cache return pipeline includes a fourth horizontal pipe, a third vertical pipe and a fifth horizontal pipe which are connected end to end in sequence from the cache tank to the upward pipeline direction.

[0025] As a further improvement of the above test platform: the pipeline bracket includes a support tube and a telescopic rod installed on the upper end of the support tube, a locking screw for fixing the telescopic rod is installed on the side of the support tube, and a pipe clamp is installed on the upper end of the telescopic rod.

[0026] As a further improvement of the above test platform: it also includes a loading system, which includes a loading bracket arranged beside the lifting support mechanism, a rotating arm installed on the top of the loading bracket and a bucket moving horizontally along the rotating arm.

[0027] The present invention also proposes a testing method based on the above-mentioned testing platform, comprising the following steps:

[0028] Step 1, assembling a pipeline system according to the filling type of the mine filling system to be simulated;

[0029] Step 2: Prepare the filling slurry in a batching and stirring device according to the mass concentration and lime-sand ratio designed in the laboratory plan. The stirring process of the batching and stirring device runs through the entire test process, and the stirring rate is adjusted in real time;

[0030] Step 3: Start the simulated conveying process of the pipeline system according to the filling type:

[0031] 1) When the filling type is gravity filling, the simulated conveying is carried out in a circulating L-pipe mode: Open the second switching valve and the third switching valve, close the first switching valve and the fourth switching valve. The slurry is directly output from the batching and mixing device to the downward pipeline, reaches the buffer tank along the downward pipeline. The slurry in the buffer tank is then under the action of the feeding pump and returns to the batching and mixing device through the buffer return pipeline and the upward pipeline in sequence, realizing the circulating gravity conveying of the downward pipeline. During the conveying process, by adjusting the flow rate of the feeding pump, the slurry level in the batching and mixing device is ensured to be stable. At the same time, the control system collects the detection data of each detection device on the pipeline system.

[0032] 2) When the filling type is downward pumping filling, the simulated conveying is carried out in a circulating L-pipe mode: Open the second switching valve, close the first switching valve, the third switching valve and the fourth switching valve. The slurry reaches the downward pipeline through the downward pumping of the filling pump from the batching and mixing device, reaches the buffer tank along the downward pipeline. The slurry in the buffer tank is then under the action of the feeding pump and returns to the batching and mixing device through the buffer return pipeline and the upward pipeline in sequence, realizing the circulating pumping conveying of the downward pipeline. During the conveying process, by adjusting the flow rates of the filling pump and the feeding pump, the slurry level in the batching and mixing device is ensured to be stable. At the same time, the control system collects the detection data of each detection device on the pipeline system.

[0033] 3) When the filling type is upward pumping filling, the simulated conveying is carried out in a circulating loop pipe mode: Open the first switching valve, close the second switching valve, the third switching valve and the fourth switching valve. The slurry reaches the downward pipeline through the downward pumping of the filling pump from the batching and mixing device, and returns to the batching and mixing device along the downward pipeline, the return pipe and the upward pipeline, realizing the circulating pumping conveying of the loop pipeline. During the conveying process, by adjusting the flow rate of the filling pump, the slurry level in the batching and mixing device is ensured to be stable. At the same time, the control system collects the detection data of each detection device on the pipeline system.

[0034] During the conveying process, if it is necessary to adjust the mass concentration of the filling slurry, the testing sequence is carried out from the highest concentration to the lowest concentration in sequence until all the slurry concentrations are tested. Each time the concentration is changed, the concentration-adjusting water in the clear water tank is added to the buffer tank according to the concentration requirement, and then the concentration-adjusting water is added to the pipeline system and the batching and mixing device through the buffer return pipeline.

[0035] Step 4: Clean the pipeline system: Close the first switching valve and the second switching valve, open the fourth switching valve, add cleaning water to the buffer tank. The cleaning water, under the action of the feeding pump, passes through the buffer return pipeline, the upward pipeline, the batching and mixing device, the downward pipeline, the discharge pipe and the sewage pipe in sequence, and finally the cleaning water reaches the sedimentation tank.

[0036] Step 5: The control system calculates the viscosity coefficient and yield stress of the slurry based on the collected test data, and then calculates the flow rate of the slurry during gravity filling in the actual mine pipeline based on the viscosity coefficient and yield stress.

[0037] As a further improvement of the test method: the specific method of step 5 is:

[0038] Step 5.1: Calculate the resistance per unit length of a typical section of the pipeline system for the slurry. There are two cases according to the temperature:

[0039] 1) When the detection device detects that the temperature of the slurry is less than 40 degrees, the resistance per unit length of the slurry in the pipeline is calculated according to the following formula:

[0040] ;

[0041] Where: , is the pressure difference between the end and the start of a typical pipeline section. is the typical pipeline section length, is the density of the slurry, is the concentration coefficient. When the mass concentration of the slurry is greater than or equal to 70% and less than 76%, k=1.25 , when the mass concentration of slurry is greater than or equal to 65% and less than 70%, k=0.8 ;

[0042] 2) When the detection device detects that the temperature of the slurry is greater than or equal to 40 degrees, the resistance per unit length of the slurry in the pipeline is calculated according to the following formula:

[0043] ;

[0044] Where: , is the pressure difference between the end and the start of a typical pipeline section. is the length of the typical pipeline section, T is the temperature of the slurry;

[0045] Step 5.2, calculate the shear stress of the slurry at the pipe wall:

[0046] ;

[0047] Where: D is the inner diameter of the pipeline;

[0048] Step 5.3: Select the average flow rate of the current slurry in different simulation tests and the corresponding shear stress , through linear fitting, we get and The linear relationship is:

[0049] ;

[0050] According to the formula ,have , , thus according to and The viscosity coefficient is calculated from the value of and yield stress ;

[0051] Step 5.4: Assume that the flow rate of the slurry during gravity filling in the actual mine pipeline is V, the total length of the gravity filling pipeline is L, and the concentration coefficient obtained according to the actual temperature is , the slurry concentration is , the inner diameter of the filling pipe is , the filling pipe height is H, then the flow rate V is calculated according to the following formula:

[0052]

[0053] Calculate two V values ​​according to the above formula and take the larger value as the result value.

[0054] Compared with the prior art, the present invention has the following beneficial effects: (1) The test platform can complete not only L-tube gravity conveying test, but also downward filling pumping test, pumping ring pipe conveying test, etc. The configuration mode is flexible and diverse, which can be consistent with the actual mining scene, improves the accuracy of simulation test, and fills the gap in the current filling slurry pipeline transportation experiment; (2) The test platform system is detachable and assembled, collects a lot of data, and has a high degree of automation control. It can meet the simulation of different forms of pipeline networks, and provides a data basis for the design and operation of underground mine filling pipeline networks, which has a guiding role; (3) When calculating the resistance per unit length of the slurry in the pipeline, the present invention fully considers the temperature, slurry density and quality. The influence of concentration on resistance, where when the temperature is low, the density and mass concentration mainly affect the resistance, while when the temperature is high, the temperature mainly has a significant impact on the resistance. The resistance is corrected according to different situations, eliminating the errors caused by other factors and improving the accuracy of the calculation results; (4) The present invention makes full use of the data of the simulation test through linear fitting to obtain the calculation results of the viscosity coefficient and the yield stress, which has the advantages of fast calculation speed, more accurate results, and closer consistency with the actual situation; (5) The present invention also proposes a flow rate calculation formula for self-flowing filling, which solves the problem that the self-flowing flow rate cannot be estimated. By comparing with the actual flow rate, its accuracy can meet the requirements of on-site use. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1This is a schematic diagram of the structure of the test platform of the present invention, in which the clear water tank and the sedimentation tank are omitted;

[0056] Figure 2 for Figure 1 Detailed schematic diagram of part A;

[0057] Figure 3 It is a schematic diagram of the structure of the clean water tank and sedimentation tank of the test platform;

[0058] Figure 4 This is a schematic diagram of the structure of the pipeline support. DETAILED DESCRIPTION

[0059] The technical solution of the present invention is described in detail below with reference to the accompanying drawings:

[0060] This embodiment discloses a test platform and method for simulating pipeline transportation of mine filling slurry.

[0061] like Figure 1 and 2 The test platform includes a batching and stirring device 2 and a pipeline system, and the batching and stirring device 2 is installed on a lifting support mechanism 4. The test platform also includes a filling pump 3, a pipeline support 5, a buffer tank 7 and a control system 8.

[0062] The pipeline system includes a feed pipeline, a down-flow pipeline, a reflux pipe 105, a discharge pipe 104, an up-flow pipeline and a buffer return pipeline.

[0063] A batching hopper is provided on the top of the batching and stirring device 2, and the batching and stirring device 2 and the filling pump 3 are connected to the feed end of the descending pipeline through a feed pipeline. The discharge end of the descending pipeline is connected to the feed end of the ascending pipeline through a reflux pipe 105 and is also connected to the feed end of the discharge pipe 104; the discharge end of the ascending pipeline is located above the batching and stirring device 2, and is used to return the slurry to the batching and stirring device 2. The discharge pipe 104 is used to send the slurry into the buffer tank 7. The discharge end of the buffer tank 7 is connected to the feed end of the ascending pipeline through a feed pump 6 and a buffer reflux pipeline in turn.

[0064] The pipeline system is equipped with a control valve and a detection device, and the detection device includes a flow meter, a pressure sensor and a temperature sensor. The control valve and the detection device are electrically connected to the control system 8. The control system 8 includes an industrial computer and a PLC. The control system 8 is used to realize process control, data acquisition and calculation.

[0065] Specifically, the feed pipeline includes a first feed pipe 113 and a second feed pipe 114 .

[0066] One end of the first feed pipe 113 is connected to the discharge end of the batching and stirring device 2, and the other end is connected to the feed end of the downward pipeline. The discharge end of the batching and stirring device 2 is also connected to the feed end of the downward pipeline through the filling pump 3 and the second feed pipe 114 in sequence.

[0067] In this embodiment, the downward pipeline includes a first vertical pipe 101, a first inclined pipe 102 and a first horizontal pipe 103 which are connected end to end in sequence from the batching and mixing device 2 to the discharge pipe 104. The upward pipeline includes a second horizontal pipe 106, a second inclined pipe 107, a second vertical pipe 108 and a third horizontal pipe 109 which are connected end to end in sequence from the return pipe 105 to the batching and mixing device 2. The buffer return pipeline includes a fourth horizontal pipe 110, a third vertical pipe 111 and a fifth horizontal pipe 112 which are connected end to end in sequence from the buffer tank 7 to the upward pipeline. The shape and composition structure of the pipeline system can also be adjusted according to the actual situation of the mine.

[0068] The control valve includes a first switch valve 201 disposed on the reflux pipe 105 , a second switch valve 202 disposed on the discharge pipe 104 , and also includes a third switch valve 203 disposed on the first feed pipe 113 .

[0069] like Figure 3 The discharge pipe 104 is also connected to a sewage pipe 115 ; the sewage pipe 115 is used to discharge the slurry into the sedimentation tank 11 , and a fourth switch valve 204 is provided on the sewage pipe 115 .

[0070] The test platform also includes a clean water tank 10 , a clean water pump 9 and a clean water pipe 116 . The clean water pipe 116 is used to introduce clean water in the clean water tank 10 into the buffer tank 7 , and the clean water pump 9 is installed on the clean water pipe 116 .

[0071] like Figure 4 The pipeline support 5 is used to support the pipeline system and also to adjust the height of the pipeline in the pipeline system. Figure 4 The pipeline support 5 includes a support tube 5-1 and a telescopic rod 5-2 installed at the upper end of the support tube 5-1, a locking screw 5-3 for fixing the telescopic rod 5-2 is installed on the side of the support tube 5-1, and a pipe clamp 5-4 is installed at the upper end of the telescopic rod 5-2.

[0072] like Figure 1 The test platform also includes a feeding system 1, which includes a feeding bracket 1-1 arranged next to the lifting support mechanism 4, a rotating arm 1-2 installed on the top of the feeding bracket 1-1, and a bucket 1-3 that moves horizontally along the rotating arm 1-2.

[0073] The test method includes the following steps:

[0074] Step 1. Assemble the piping system according to the filling type of the mine filling system to be simulated. Debug the pump, flow meter, pressure sensor, temperature sensor, switch valve and other equipment to ensure that the electrical equipment and instrumentation are normal. Turn on the high-pressure water to test the platform system to ensure that the system is normal and stable. At the same time, prepare materials, water and various additives.

[0075] Step 2: Prepare the filling slurry in the batching and mixing device 2 according to the mass concentration and lime-sand ratio designed in the laboratory plan. The mixing process of the batching and mixing device 2 runs through the entire test process, and the mixing rate is adjusted in real time.

[0076] Step 3: Start the simulated delivery process of the pipeline system according to the filling type:

[0077] 1) When the filling type is gravity filling, a circulating L-tube method is used to simulate transportation: open the second switch valve 202 and the third switch valve 203, close the first switch valve 201 and the fourth switch valve 204, and the slurry is directly output from the batching and stirring device 2 to the downward pipeline, and reaches the buffer tank 7 along the downward pipeline. Under the action of the feed pump 6, the slurry in the buffer tank 7 returns to the batching and stirring device 2 through the buffer reflux pipeline and the upward pipeline in sequence, thereby realizing circulating gravity transportation of the downward pipeline. During the transportation process, the material level in the batching and stirring device 2 is kept stable by adjusting the flow rate of the feed pump 6, and at the same time, the control system 8 collects the detection data of each detection device on the pipeline system.

[0078] 2) When the filling type is downward pumping filling, a circulating L-tube method is used to simulate transportation: open the second switch valve 202, close the first switch valve 201, the third switch valve 203 and the fourth switch valve 204, and the slurry is pumped from the batching and stirring device 2 to the downward pipeline through the downward pumping of the filling pump 3, and then reaches the buffer tank 7 along the downward pipeline. The slurry in the buffer tank 7 is then returned to the batching and stirring device 2 through the buffer reflux pipeline and the upward pipeline under the action of the feed pump 6, thereby realizing circulating pumping transportation in the downward pipeline. During the transportation process, the material level in the batching and stirring device 2 is kept stable by adjusting the flow rates of the filling pump 3 and the feed pump 6, and at the same time, the control system 8 collects the detection data of each detection device on the pipeline system.

[0079] 3) When the filling type is upward pumping filling, a circulating ring pipe method is used to simulate transportation: open the first switch valve 201, close the second switch valve 202, the third switch valve 203 and the fourth switch valve 204, and the slurry is pumped from the batching and stirring device 2 to the downward pipeline through the filling pump 3, and returns to the batching and stirring device 2 along the downward pipeline, the reflux pipe 105 and the upward pipeline, realizing the circulating pumping transportation of the ring pipeline; during the transportation process, the flow rate of the filling pump 3 is adjusted to ensure the stability of the material level in the batching and stirring device 2, and at the same time, the control system 8 collects the detection data of each detection device on the pipeline system.

[0080] During the transportation process, if the mass concentration of the filling slurry needs to be adjusted, the test sequence is carried out from the highest concentration to the lowest concentration until all slurry concentration tests are completed; each time the concentration is changed, the concentrated water in the clear water tank 10 is added to the buffer tank 7 according to the concentration requirements, and then the concentrated water is added to the pipeline system and the batching and mixing device 2 through the buffer return pipeline.

[0081] Step 4, cleaning the pipeline system: close the first switch valve 201 and the second switch valve 202, open the fourth switch valve 204, add cleaning water to the buffer tank 7, and under the action of the feed pump 6, the cleaning water passes through the cache reflux pipeline, the upstream pipeline, the batching and stirring device 2, the downstream pipeline, the discharge pipe 104 and the sewage pipe 115 in sequence, and finally the cleaning water reaches the sedimentation tank 11.

[0082] Step 5: The control system 8 calculates the viscosity coefficient and yield stress of the slurry based on the collected detection data, and then calculates the flow rate of the slurry during gravity filling in the actual mine pipeline based on the viscosity coefficient and yield stress.

[0083] The specific steps include:

[0084] Step 5.1. Calculate the resistance per unit length of the slurry in a typical section of the pipeline system.

[0085] During the pipeline transportation of filling slurry, the collision and friction between solid particles and cement hydration will generate heat, which can be described as the heat transfer phenomenon during the slurry transportation process. The temperature sensor can be used to measure the temperature change during the slurry transportation process. The test found that as the temperature rises, the rheological parameters of the filling slurry change during the pipeline transportation process, and the plastic viscosity coefficient and yield stress continue to decrease. Based on the influence of temperature on the rheological properties of the slurry, the following model is proposed. The model is divided into two cases according to temperature:

[0086] 1) When the detection device detects that the temperature of the slurry is less than 40 degrees, the resistance per unit length of the slurry in the pipeline is calculated according to the following formula:

[0087] ;

[0088] Where: , is the pressure difference between the end and the start of a typical pipeline section. is the typical pipeline section length, is the density of the slurry, is the concentration coefficient. When the mass concentration of the slurry is greater than or equal to 70% and less than 76%, k=1.25 , when the mass concentration of slurry is greater than or equal to 65% and less than 70%, k=0.8 ;

[0089] 2) When the detection device detects that the temperature of the slurry is greater than or equal to 40 degrees, the resistance per unit length of the slurry in the pipeline is calculated according to the following formula:

[0090] ;

[0091] Where: , is the pressure difference between the end and the start of a typical pipeline section. is the length of the typical pipeline section, T is the temperature of the slurry;

[0092] Step 5.2, calculate the shear stress of the slurry at the pipe wall:

[0093] ;

[0094] Where: D is the inner diameter of the pipeline;

[0095] Step 5.3: Select the average flow rate of the current slurry in different simulation tests and the corresponding shear stress , through linear fitting, we get and The linear relationship is:

[0096] ;

[0097] According to the formula ,have , , thus according to and The viscosity coefficient is calculated from the value of and yield stress .

[0098] In this embodiment, the lime-sand mass ratio is 1:10, the slurry concentration is 74%, the inner diameter of the pipeline is D78, the typical pipeline section length is 7.9m, and the flow rate is 20-40m³ / h. By calculation, it can be obtained that the pressure loss per unit length j is 5327.61pa / m, and the shear stress of the pipe wall is is 103.89 pa, and the fitted and are 0.085 and 84.705 respectively, and the yield stress It is 63.52875pa.

[0099] Step 5.4: Assume that the flow rate of the slurry during gravity filling in the actual mine pipeline is V, the total length of the gravity filling pipeline is L, and the concentration coefficient obtained according to the actual temperature is , the slurry concentration is , the inner diameter of the filling pipe is , the filling pipe height is H, then the flow rate V is calculated according to the following formula:

[0100]

[0101] According to the above formula, two V values ​​can be calculated. In actual calculation, the smaller value is always a negative value, and the larger value is taken as the result value.

Claims

1. A test platform for simulating pipeline transportation of mine filling slurry, comprising a batching and stirring device (2) and a pipeline system, Features: The batching and stirring device (2) is installed on a lifting support mechanism (4); The test platform also includes a filling pump (3), a pipeline support (5), a buffer tank (7) and a control system (8); The pipeline support (5) is used to support the pipeline system and to adjust the height of the pipeline in the pipeline system; The pipeline system comprises a feed pipeline, a down-flow pipeline, a reflux pipe (105), a discharge pipe (104), an up-flow pipeline and a buffer reflux pipeline; The batching and stirring device (2) and the filling pump (3) are connected to the feed end of the descending pipeline through a feed pipeline, and the discharge end of the descending pipeline is connected to the feed end of the ascending pipeline through a reflux pipe (105) and is also connected to the feed end of the discharge pipe (104); the discharge end of the ascending pipeline is located above the batching and stirring device (2) and is used to return the slurry to the batching and stirring device (2); the discharge pipe (104) is used to send the slurry into the buffer tank (7); the discharge end of the buffer tank (7) is connected to the feed end of the ascending pipeline through a feed pump (6) and a buffer reflux pipeline in sequence; The pipeline system is equipped with a control valve and a detection device, wherein the detection device includes a flow meter, a pressure sensor and a temperature sensor; the control valve and the detection device are both electrically connected to the control system (8); The feed pipeline comprises a first feed pipe (113) and a second feed pipe (114); One end of the first feed pipe (113) is connected to the discharge end of the batching and stirring device (2), and the other end is connected to the feed end of the downward pipeline; The discharge end of the batching and stirring device (2) is also connected to the feed end of the downward pipeline through the filling pump (3) and the second feed pipe (114) in sequence; The control valve comprises a third switch valve (203) arranged on the first feed pipe (113); the control valve comprises a first switch valve (201) arranged on the return pipe (105) and a second switch valve (202) arranged on the discharge pipe (104); The discharge pipe (104) is also connected to a sewage pipe (115); the sewage pipe (115) is used to discharge the slurry into the sedimentation tank (11), and a fourth switch valve (204) is provided on the sewage pipe (115); The steps of performing the test based on the test platform include: Step 1, assembling a pipeline system according to the filling type of the mine filling system to be simulated; Step 2: Prepare the filling slurry in the batching and stirring device (2) according to the mass concentration and lime-sand ratio designed in the laboratory plan. The stirring process of the batching and stirring device (2) runs through the entire test process, and the stirring rate is adjusted in real time; Step 3: Start the simulated delivery process of the pipeline system according to the filling type: 1) When the filling type is gravity filling, the circulating L-pipe method is used to simulate the conveying: Open the second on-off valve (202) and the third on-off valve (203), close the first on-off valve (201) and the fourth on-off valve (204). The slurry is directly output from the batching and mixing device (2) to the downpipe, reaches the buffer tank (7) along the downpipe. The slurry in the buffer tank (7) then returns to the batching and mixing device (2) successively through the buffer return pipe and the uppipe under the action of the feeding pump (6), realizing the circulating gravity conveying of the downpipe. During the conveying process, by adjusting the flow rate of the feeding pump (6), the slurry level in the batching and mixing device (2) is ensured to be stable. At the same time, the control system (8) collects the detection data of each detection device on the pipeline system. 2) When the filling type is downward pumping filling, the circulating L-pipe method is used to simulate the conveying: Open the second on-off valve (202), close the first on-off valve (201), the third on-off valve (203) and the fourth on-off valve (204). The slurry is pumped downward by the filling pump (3) from the batching and mixing device (2) to the downpipe, reaches the buffer tank (7) along the downpipe. The slurry in the buffer tank (7) then returns to the batching and mixing device (2) successively through the buffer return pipe and the uppipe under the action of the feeding pump (6), realizing the circulating pumping conveying of the downpipe. During the conveying process, by adjusting the flow rates of the filling pump (3) and the feeding pump (6), the slurry level in the batching and mixing device (2) is ensured to be stable. At the same time, the control system (8) collects the detection data of each detection device on the pipeline system. 3) When the filling type is upward pumping filling, the circulating loop pipe method is used to simulate the conveying: Open the first on-off valve (201), close the second on-off valve (202), the third on-off valve (203) and the fourth on-off valve (204). The slurry is pumped downward by the filling pump (3) from the batching and mixing device (2) to the downpipe, and returns to the batching and mixing device (2) along the downpipe, the return pipe (105) and the uppipe, realizing the circulating pumping conveying of the loop pipeline. During the conveying process, by adjusting the flow rate of the filling pump (3), the slurry level in the batching and mixing device (2) is ensured to be stable. At the same time, the control system (8) collects the detection data of each detection device on the pipeline system. During the conveying process, if it is necessary to adjust the mass concentration of the filling slurry, the testing sequence is carried out from the highest concentration to the lowest concentration in turn until all the slurry concentrations are tested. Each time the concentration is changed, the concentration-adjusting water in the clear water tank (10) is added to the buffer tank (7) according to the concentration requirement, and then the concentration-adjusting water is added to the pipeline system and the batching and mixing device (2) through the buffer return pipe. Step 4: Clean the pipeline system: Close the first on-off valve (201) and the second on-off valve (202), open the fourth on-off valve (204), add cleaning water to the buffer tank (7). The cleaning water, under the action of the feeding pump (6), successively passes through the buffer return pipe, the uppipe, the batching and mixing device (2), the downpipe, the discharge pipe (104) and the sewage pipe (115), and finally the cleaning water reaches the sedimentation tank (11). Step 5, the control system (8) calculates the viscosity coefficient and yield stress of the slurry according to the collected detection data, when the filling type is gravity filling, and then calculates the flow rate of the slurry during gravity filling in the actual mine pipeline according to the viscosity coefficient and yield stress; The specific method of step 5 is: Step 5.1: Calculate the resistance per unit length of a typical section of the pipeline system for the slurry. There are two cases according to the temperature: 1) When the detection device detects that the temperature of the slurry is less than 40 degrees, the resistance per unit length of the slurry in the pipeline is calculated according to the following formula: Where: ΔP is the pressure difference between the end and the start of a typical pipeline section, l is the length of a typical pipeline section, ρ is the density of the slurry, k is the concentration coefficient, when the mass concentration of the slurry is greater than or equal to 70% and less than 76%, k = 1.25s 2 / m, when the mass concentration of slurry is greater than or equal to 65% and less than 70%, k = 0.8s 2 / m; 2) When the detection device detects that the temperature of the slurry is greater than or equal to 40 degrees, the resistance per unit length of the slurry in the pipeline is calculated according to the following formula: Where: ΔP is the difference in pressure between the end and the start of a typical pipeline section, l is the length of the typical pipeline section, and T is the temperature of the slurry; Step 5.2, calculate the shear stress of the slurry at the pipe wall: Where: D is the inner diameter of the pipeline; Step 5.3: Select the average flow velocity v and the corresponding shear stress τ of the current slurry in different simulation tests. w , through linear fitting, we get τ w Linear relationship with v: t w =a×v+b; According to the formula have Thus, the viscosity coefficient η and yield stress τ can be calculated based on the values ​​of a and b. 0 ; Step 5.4: Assume that the flow rate of the slurry during gravity filling in the actual mine pipeline is V, the total length of the gravity filling pipeline is L, the concentration coefficient obtained according to the actual temperature is k, the slurry concentration is ρ, and the inner diameter of the filling pipeline is D 0 , the filling pipe height is H, then the flow rate V is calculated according to the following formula: Calculate two V values ​​according to the above formula and take the larger value as the result value.

2. The test platform for simulating pipeline transportation of mine filling slurry as claimed in claim 1, Features: It also includes a clean water tank (10), a clean water pump (9) and a clean water pipe (116), wherein the clean water pipe (116) is used to introduce clean water in the clean water tank (10) into the buffer tank (7), and the clean water pump (9) is installed on the clean water pipe (116).

3. The test platform for simulating pipeline transportation of mine filling slurry as claimed in claim 1, Features: The downward pipeline comprises a first vertical pipe (101), a first inclined pipe (102) and a first horizontal pipe (103) which are connected end to end in sequence from the batching and stirring device (2) to the discharge pipe (104); the upward pipeline comprises a second horizontal pipe (106), a second inclined pipe (107), a second vertical pipe (108) and a third horizontal pipe (109) which are connected end to end in sequence from the return pipe (105) to the batching and stirring device (2); The buffer return pipeline comprises a fourth horizontal pipe (110), a third vertical pipe (111) and a fifth horizontal pipe (112) which are sequentially connected end to end in the upward pipeline direction from the buffer tank (7).

4. The test platform for simulating pipeline transportation of mine filling slurry as claimed in claim 1, Features: The pipeline support (5) comprises a support tube (5-1) and a telescopic rod (5-2) mounted on the upper end of the support tube (5-1); a locking screw (5-3) for fixing the telescopic rod (5-2) is mounted on the side of the support tube (5-1); and a pipe clamp (5-4) is mounted on the upper end of the telescopic rod (5-2).

5. The test platform for simulating pipeline transportation of mine filling slurry as claimed in claim 1, Features: It also includes a loading system (1), the loading system (1) comprising a loading bracket (1-1) arranged beside the lifting support mechanism (4), a rotating arm (1-2) installed at the top of the loading bracket (1-1), and a bucket (1-3) moving horizontally along the rotating arm (1-2).

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