High-coupling mounting assembly and device for micro-seismic sensor in rock mass

Abstract

The utility model provides a high-coupling installation assembly and device for a micro-seismic sensor in a rock mass, and belongs to the technical field of micro-seismic monitoring. The micro-seismic sensor high-coupling installation assembly is provided with an inner sleeve, a fixed inner plate, a conduction bolt, a spring and a cavity conduit, and can apply a pre-tightening force to a micro-seismic sensor to realize full contact with a signal conduction medium, so that the signal coupling degree is improved, the signal quality is ensured, and meanwhile, recycling of the micro-seismic sensor can be realized; according to the micro-seismic sensor high-coupling installation device, after a hole is drilled in a rock mass, recoverable high-strength coupling and low-noise fixed installation of a micro-seismic sensor is completed through coordinated operation among the rock mass riveting mechanism, the coupling noise reduction mechanism and the micro-seismic sensor high-coupling installation assembly; the device is simple and convenient to operate, high in reliability, high in working efficiency, time-saving and labor-saving, good in mounting effect, high in signal acquisition rate, low in noise and relatively low in construction cost.

Description

Technical Field

[0001] The utility model belongs to the technical field of microseismic monitoring, and specifically relates to a noise reduction high-coupling installation component and an installation device for a microseismic sensor in a rock body, which realizes the sound preservation and noise reduction installation of the sensor in the geological rock body and the recycling and reuse of the sensor. Background Art

[0002] In the fields of mining, tunneling, dam construction, foundation construction, etc., in order to ensure the safety and stability of rock and soil, microseismic monitoring is often carried out to focus on its overall stability. For example, due to the frequent occurrence of rock burst accidents and water inrush accidents in coal mines, microseismic monitoring systems are installed to monitor the stress and damage of the surrounding rock of the mine. However, the cost of microseismic sensors is relatively high, averaging 15,000 yuan each. The effective and accurate monitoring radius of each sensor is 50m. For a working face with a push length of 1,000m, 20*2=40 sensors are required, costing about 600,000 yuan.

[0003] At present, the traditional way to install sensors is to bury them deep in the well by drilling. The sensors cannot be recycled and buried directly in the well, which causes waste of materials. In addition, the coupling degree of microseismic signals is low, and the quality of microneedle signals cannot be guaranteed. Some existing solutions are to use anchor rods to install sensors. By connecting the sensors to the anchor rods and anchoring the anchor rods into the deep rock mass, the sensors are placed at the ends of the anchor rods. For tunnels where it is inconvenient to use on-site drilling tools, the original anchor rods on site are directly used for installation. However, these devices or devices have many problems, such as poor contact between sensors and anchor rods, excessive noise, poor signal transmission due to coupling degree, resulting in the loss of some microseismic signals, which cannot meet the needs of safe production.

[0004] Therefore, the utility model provides a high-coupling installation component and installation device for microseismic sensors in rock bodies, which realize safe and effective signal collection and transmission, while improving the recycling rate and installation success rate of the sensor, reducing the sensor damage rate, and improving work efficiency. Utility Model Content

[0005] The purpose of the utility model is to provide a high-coupling installation component and device for microseismic sensors in rock bodies, so as to realize safe and effective signal collection and transmission, improve the recycling rate and installation success rate of sensors, reduce the damage rate of sensors, improve work efficiency, realize mechanization and reduce costs.

[0006] The technical solution adopted by the utility model to achieve the above-mentioned purpose is:

[0007] A high-coupling installation assembly for microseismic sensors in a rock body, comprising:

[0008] An inner sleeve, wherein the inner sleeve is a cylindrical structure with a closed upper end and an open lower end;

[0009] A fixed inner plate, which is circular and connected to the inner wall of the inner sleeve and can move up and down inside the inner sleeve;

[0010] A conductive bolt, which is connected to one end of the microseismic sensor and is used to receive the microseismic signal transmitted by the signal conductive medium; the other end of the microseismic sensor is connected to the bottom of the fixed inner plate;

[0011] A spring, wherein the spring is connected between the fixed inner plate and the inner side wall of the top of the inner sleeve, so that the conductive bolt on the microseismic sensor is in full contact with the signal conductive medium;

[0012] A cavity conduit, one end of which is fixed on the fixed inner plate, and the other end of which passes through the top center of the inner sleeve, is used to allow the wire of the microseismic sensor to pass through and extend outside the device to achieve signal transmission.

[0013] According to some embodiments of the utility model, a high-coupling installation assembly of a microseismic sensor in a rock mass also includes a conductive tube, which is arranged outside the inner sleeve and connected to the cavity conduit; the conductive tube is a rigid tube, and its outer diameter is larger than the outer diameter of the cavity conduit.

[0014] According to some embodiments of the utility model, a high-coupling installation assembly for a microseismic sensor in a rock mass is provided, wherein a plurality of strip-shaped grooves are provided on the upper portion of the inner sleeve along the circumferential direction of the inner wall; a lock is provided on the edge of the fixed inner plate for cooperating with the groove at the corresponding position, and the fixed inner plate moves up and down along the groove inside the inner sleeve through the lock.

[0015] According to a high-coupling installation assembly for a microseismic sensor in a rock mass in some embodiments of the utility model, a bolt groove for installing the microseismic sensor is provided at the bottom center of the fixed inner plate, and the bolt groove is connected to the cavity conduit.

[0016] A high-coupling installation device for microseismic sensors in a rock body, comprising:

[0017] The rock riveting mechanism is a hollow cylindrical structure as a whole, with a detachable top end connected to a fixing cover, a closed bottom end and a pointed cone shape, and is used to drill and fix the entire installation device into the rock at the bottom of the borehole;

[0018] A coupling noise reduction mechanism, the coupling noise reduction mechanism comprising a probe, a partition and a grouting pipe; the partition is arranged in the rock riveting mechanism and is located at the lower part of the rock riveting mechanism, and separates the lower space of the rock riveting mechanism into a slurry cavity for enhancing coupling; the grouting pipe is inserted into the partition and communicated with the slurry cavity, and is used to pour noise reduction material into the slurry cavity; the slurry cavity is connected with the drill hole through the external seepage hole arranged on the rock riveting mechanism, so as to ensure that the noise reduction material is poured in as a whole; the probe is a structure with a T-shaped cross section composed of a horizontal plate and a vertical rod;

[0019] A microseismic sensor high-coupling installation assembly; wherein the inner sleeve is placed on the partition; the horizontal plate of the probe is connected to the bottom of the inner sleeve and contacts the conductive bolt, and the connection position of the probe in the height direction of the inner sleeve is adjustable; the vertical rod of the probe passes through the center of the partition and contacts with the coupling hole set in the center of the bottom of the rock riveting mechanism.

[0020] According to some embodiments of the utility model, a high-coupling installation device for a microseismic sensor in a rock mass is provided, wherein the lower part of the inner sleeve is provided with a spirally distributed retaining ring along the height direction of the inner wall; the edge of the horizontal plate of the probe is provided with a buckle that cooperates with the retaining ring, and the buckle cooperates with the retaining ring to realize the screwing in and out of the probe along the height direction of the inner sleeve and the fixation of the position.

[0021] According to some embodiments of the utility model, a high-coupling installation device for a microseismic sensor in a rock mass is provided, wherein the rock mass riveting mechanism is formed by a fixing cover, an outer sleeve, and a pointed head connected in sequence; the pointed head is a hollow cone structure, which is connected to the bottom end of the outer sleeve, and the two constitute an integrated structure with a hollow interior; the fixing cover is installed on the top end of the outer sleeve, and pre-tightening bolts are installed on the fixing cover to facilitate drilling the rock mass riveting mechanism into the rock mass at the bottom of the borehole.

[0022] According to a high-coupling installation device for a microseismic sensor in a rock mass in some embodiments of the utility model, the outer sleeve and the tip head are provided with continuous external threads to facilitate drilling into the rock mass at the bottom of the borehole.

[0023] According to some embodiments of the utility model, a high-coupling installation device for a microseismic sensor in a rock mass is provided, a plurality of external seepage holes are provided on the side wall of the pointed head, and a spacer is provided at the external port of the external seepage hole; the bursting pressure of the spacer is above 5KPa, ensuring that the slurry is first filled in the slurry cavity and then penetrates into the borehole.

[0024] According to a high-coupling installation device for a microseismic sensor in a rock mass in some embodiments of the utility model, the partition is connected inside the outer sleeve and is located at the lower end of the outer sleeve, and the slurry cavity is formed between the partition, the outer sleeve and the pointed head.

[0025] The beneficial effects of the utility model are as follows: the high-coupling installation component of the microseismic sensor of the utility model can apply a pre-tightening force to the microseismic sensor to achieve full contact with the signal transmission medium, thereby improving the signal coupling degree to ensure signal quality, and at the same time can realize the recycling of the microseismic sensor; after drilling a hole in the rock body, the high-coupling installation device of the microseismic sensor coordinates the operation between the rock riveting mechanism, the coupling noise reduction mechanism and the high-coupling installation component of the microseismic sensor to complete the recyclable high-strength coupling and low-noise fixed installation of the microseismic sensor; the utility model is easy to operate, has high reliability, high work efficiency, saves time and effort, has a good installation effect, has a high signal acquisition rate, low noise, and has a relatively low construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is an overall schematic diagram of the installation device described in the embodiment of the utility model.

[0027] Figure 2 It is a top view of the lower part of the inner cavity of the installation device described in the embodiment of the utility model.

[0028] Figure 3 This is a top view of the upper inner cavity of the installation device described in the embodiment of the utility model.

[0029] Figure 4 It is a partial enlarged view of the partition described in the embodiment of the utility model.

[0030] Figure 5 It is a partial enlarged view of the probe described in the embodiment of the utility model.

[0031] Figure 6 This is an enlarged view of the interior of the inner sleeve described in the embodiment of the utility model.

[0032] Figure 7 It is a partial enlarged view of the fixed inner plate described in the embodiment of the utility model.

[0033] Figure 8 It is a partial enlarged view of the pointed tip described in the embodiment of the utility model.

[0034] In the figure: 1 transmission bolt; 2 microseismic sensor; 3 sensor bolt; 4 cavity guide tube; 5 transmission tube; 6 fixing cover; 7 pre-tightening bolt; 8 bolt; 9 wire; 10 external thread; 11 outer sleeve; 12 spring; 13 fixed inner plate; 14 inner sleeve; 15 external seepage hole; 16 spacer; 17 pointed head; 18 probe rod; 19 slurry cavity; 20 partition; 21 grouting pipe; 22 drill hole; 23 retaining ring; 24 retaining groove; 25 pipe hole; 26 exploration hole; 27 buckle; 28 bolt groove; 29 lock; 30 spring buckle; 31 coupling hole. DETAILED DESCRIPTION

[0035] The technical solution of the present utility model will be described in detail below in conjunction with the accompanying drawings.

[0036] like Figure 1 and Figure 6 As shown, an embodiment of the utility model provides a high-coupling installation assembly of a microseismic sensor in a rock mass, including an inner sleeve 14, a fixed inner plate 13, a conductive bolt 1, a spring 12, a cavity guide tube 4 and a conductive tube 5.

[0037] The inner sleeve 14 is a cylindrical structure made of steel with a closed upper end and an open lower end, and a wall thickness of 5 mm. Four vertical strip grooves 24 are evenly spaced along the circumferential direction of the inner wall on its upper part; the fixed inner plate 13 is circular, and its edge is provided with a lock 29 that cooperates with the groove 24 at the corresponding position. The fixed inner plate 13 moves up and down inside the inner sleeve 14 along the groove 24 through the lock 29.

[0038] The conductive bolt 1 is connected to one end of the microseismic sensor 2 for receiving signals; the other end of the microseismic sensor 2 is connected to a bolt groove 28 provided at the bottom center of the fixed inner plate 13 .

[0039] The spring 12 is connected between the fixed inner plate 13 and the inner side wall of the top of the inner sleeve 14, so that the conductive bolt 1 on the microseismic sensor is in full contact with the signal conductive medium.

[0040] One end of the cavity conduit 4 is fixed on the fixed inner plate 13, and the other end passes through the top center of the inner sleeve 14, so as to allow the wire of the microseismic sensor to pass through and extend outside the device to realize signal transmission.

[0041] The conduction tube 5 is arranged outside the inner sleeve 14 and connected to the cavity catheter 4 ; the conduction tube 5 is a rigid tube, and its outer diameter is greater than the outer diameter of the cavity catheter 4 .

[0042] like Figure 1 As shown, the embodiment of the utility model also provides a high-coupling installation device for microseismic sensors in rock bodies, including a rock riveting mechanism, a coupling noise reduction mechanism and a high-coupling installation assembly for the microseismic sensor; the rock riveting mechanism is composed of a fixed cover 6, an outer sleeve 11, and a pointed head 17 connected in sequence, and is a fixed assembly in the rock body of the device; the coupling noise reduction mechanism is composed of a probe 18, a partition 20 and a grouting pipe 21, and the entire mechanism is arranged at the lower end of the device to improve the coupling and reduce the influence of noise; the high-coupling installation assembly for the microseismic sensor is composed of an inner sleeve 14, a fixed inner plate 13, a spring 12, a conductive bolt 1, a cavity guide tube 4 and a conductive tube 5, which can apply a pre-tightening force to the microseismic sensor to achieve full contact with the probe.

[0043] The specific implementation steps of collecting microseismic signals using the above-mentioned installation device are as follows:

[0044] S1: Fabrication and installation of high-coupling mounting devices for microseismic sensors

[0045] S1.1: Design the aperture and length of the conductive bolt 1, bolt slot 28 and inner sleeve 14 according to the specifications of the microseismic sensor 2, sensor bolt 3 and wire 9 used at the project site; Figure 7 As shown, a bolt groove 28 is opened at the bottom of the fixed inner plate 13 , a cavity conduit 4 is installed at the center of the fixed inner plate 13 and the cavity conduit 4 is connected to the bolt groove 28 ; a latch 29 is arranged at the edge of the fixed inner plate 13 .

[0046] S1.2: A plurality of slots 24 are formed on the inner wall of the upper half of the inner sleeve 14, a spring buckle 30 is welded to the inner end and a spring 12 with high telescopic capacity is hung, and the spring buckle 30 on the fixed inner plate 13 is connected to the spring 12, see Figure 3 ;

[0047] S1.3: If Figure 1 and Figure 6 As shown, one end of the microseismic sensor 2 is mounted on the bolt groove 28 of the fixed inner plate 13 through the sensor bolt 3, and the other end is connected to the conductive bolt 1; the sensor wire 9 passes through the bolt groove 28 on the fixed inner plate 13 and the cavity conduit 4 in sequence and extends outward; the latch 29 on the fixed inner plate 13 is pushed into the latch groove 24 of the inner sleeve 14 to achieve connection;

[0048] S1.4: If Figure 2 and Figure 5 As shown, a spiral clamping ring 23 is provided on the inner wall of the lower half of the inner sleeve 14, and the two sections of the inner sleeve 14 are welded together to ensure the internal stability of the microseismic sensor; the probe 18 is a structure made of steel and composed of a horizontal plate and a vertical rod with a T-shaped cross section, and a buckle 27 is provided on the edge of the horizontal plate of the probe 18. The probe 18 is screwed into the inner sleeve 14 through the cooperation of the buckle 27 and the clamping ring 23, so that the probe 18 is fully in contact with the conductive bolt 1; the cooperation of the clamping ring 23 and the clamping ring 27 is preferably a threaded connection;

[0049] S1.5: The inner diameter of the outer sleeve 11 is designed according to the overall size of the inner sleeve 14, and the wall thickness of the outer sleeve 11 is greater than 1.5 cm; at the same time, the outer sleeve 11 is provided with an external thread 10;

[0050] S1.6: If Figure 4 As shown, a partition 20 is made according to the inner diameter of the outer sleeve 11, and the thickness of the partition 20 is greater than 5 mm; then, a probe hole 26 and a pipe hole 25 are opened on the partition 20 according to the size of the vertical rod of the probe rod 18 and the grouting pipe 21, and a sealing spacer 16 is installed on the probe hole 26 and the pipe hole 25; and then the partition 20 is welded to the lower part of the outer sleeve 11;

[0051] S1.7: A tip 17 is made according to the outer sleeve 11. The tip 17 is provided with an external thread 10, a coupling hole 31 is provided at the center of the bottom, and a plurality of external leakage holes 15 are provided on the side wall; the size of the coupling hole 31 is associated with the size of the vertical rod of the probe 18, the aperture of the external leakage hole 15 is greater than 3mm, and the structure of the tip 17 is shown in Figure 8 ;

[0052] S1.8: If Figure 1 As shown, the pointed head 17 is welded to the bottom of the outer sleeve 11, and a slurry chamber 19 is formed between the partition 20, the pointed head 17 and the outer sleeve 11; and the fixing cover 6, the pre-tightening bolts 7 and the conductive tube 5 are manufactured based on the parameters of the outer sleeve 11. The conductive tube 5 and the pre-tightening bolts 7 can meet the on-site drilling torque for safe on-site use.

[0053] S2: Use of high-coupling mounting device for microseismic sensors and recovery of microseismic sensors

[0054] S2.1: Drilling is performed according to the outer diameter of the outer sleeve 11, and the drilling depth meets the microseismic sensor installation requirements;

[0055] S2.2: The fixing cover 6 is installed on the top of the outer sleeve 11 by means of bolts 8, and the overall drilling is performed by means of the pre-tightening bolts 7 on the fixing cover 6, so that the tip 17 can drill into the rock mass at the bottom of the borehole;

[0056] S2.3: Remove the bolts 8 and the fixing cover 6, and insert the grouting pipe 21 into the slurry cavity 19 through the pipe hole 25;

[0057] S2.4: Connect the conductive tube 5 to the cavity conduit 4, and use the conductive tube 5 to drive the inner sleeve 14 to make the probe 18 pass through the probe hole 26 into the slurry cavity 19 and fit into the coupling hole 31;

[0058] S2.5: Use the grouting pipe 21 to inject ultrafine cement into the slurry cavity 19. The ultrafine cement first diffuses in the slurry cavity 19. After the slurry cavity 19 and the gap between the probe 18 and the coupling hole 31 are filled, the ultrafine cement breaks through the external seepage hole 15 and seeps outward into the borehole 22. After the hole is filled, the grouting is stopped; the ultrafine cement slurry flows from the slurry cavity 19 at the bottom through the external seepage hole 15 to the outside, so as to better achieve coupling with the borehole rock mass, and the gap between the probe hole 26 and the coupling hole 31 is also filled under the action of pressure, so that the rock mass at the bottom of the borehole, the tip 17, the probe 18 and the conductive bolt 1 form a complete coupling system to achieve better signal transmission.

[0059] S2.6: After the whole is stable, add sound insulation cotton into the outer sleeve 11 and install the fixed cover 6 to block the interference of external noise;

[0060] S2.7: Implement the monitoring task; after the monitoring task is completed, rotate the conductive tube 5 to unscrew the inner sleeve 14 from the probe 18 and drive the inner sleeve 14 to remove the assembled microseismic sensor high-coupling installation assembly, thereby completing the recycling and reuse of the microseismic sensor.

[0061] Finally, it should be noted that the above embodiments are intended to illustrate the technical solutions of the present invention and do not constitute any form of limitation on the present invention. Those skilled in the art should fully understand that it is completely feasible to modify the technical solutions described in the above embodiments or to replace any part or all of the technical features therein with equivalents. These modifications or replacements, as long as they do not deviate from the scope of protection determined by the claims of the present invention, should be regarded as reasonable extensions of the present invention.

Claims

1. A high-coupling installation assembly for microseismic sensors in a rock mass, characterized in that: include: An inner sleeve (14), the inner sleeve (14) being a cylindrical structure with a closed upper end and an open lower end; A fixed inner plate (13), the fixed inner plate (13) is circular and connected to the inner wall of the inner sleeve (14), and can move up and down inside the inner sleeve (14); A conductive bolt (1), the conductive bolt (1) being connected to one end of a microseismic sensor and used for receiving a signal transmitted by a signal conductive medium; the other end of the microseismic sensor being connected to the bottom of the fixed inner plate (13); A spring (12), wherein the spring (12) is connected between the fixed inner plate (13) and the inner side wall of the top of the inner sleeve (14), so that the conductive bolt (1) on the microseismic sensor is in full contact with the signal conductive medium; A cavity conduit (4), one end of which is fixed on the fixed inner plate (13), and the other end of which passes through the top center of the inner sleeve (14), and is used to allow the wire of the microseismic sensor to pass through and extend outside the device to achieve signal transmission.

2. The high-coupling installation assembly of a microseismic sensor in a rock body according to claim 1, characterized in that: It also comprises a conduction tube (5), which is arranged outside the inner sleeve (14) and connected to the cavity catheter (4); the conduction tube (5) is a rigid tube, and its outer diameter is larger than the outer diameter of the cavity catheter (4).

3. The high-coupling installation assembly of microseismic sensors in rock mass according to claim 1, characterized in that: The upper part of the inner sleeve (14) is provided with a plurality of strip-shaped slots (24) along the circumferential direction of the inner wall; the edge of the fixed inner plate (13) is provided with a locking lock (29) that cooperates with the slots (24) at corresponding positions, and the fixed inner plate (13) moves up and down inside the inner sleeve (14) along the slots (24) through the locking lock (29).

4. The high-coupling installation assembly for microseismic sensors in rock mass according to claim 1, characterized in that: A bolt groove (28) for mounting a microseismic sensor is provided at the bottom center of the fixed inner plate (13), and the bolt groove (28) is communicated with the cavity conduit (4).

5. A high-coupling installation device for microseismic sensors in rock mass, characterized in that: include: A rock mass riveting mechanism, the rock mass riveting mechanism is a hollow cylindrical structure as a whole, the top end of which is detachably connected to a fixing cover (6), the bottom end is closed and has a pointed cone shape, and is used to drill and fix the entire installation device into the rock mass at the bottom of the borehole; A coupling noise reduction mechanism, the coupling noise reduction mechanism comprising a probe (18), a partition (20) and a grouting pipe (21); the partition (20) is arranged in the rock mass riveting mechanism and is located at the lower part of the rock mass riveting mechanism, and separates the lower space of the rock mass riveting mechanism into a slurry chamber (19) for enhancing coupling; the grouting pipe (21) is inserted into the partition (20) and communicates with the slurry chamber (19), and is used to inject noise reduction material into the slurry chamber; the slurry chamber (19) is connected to the borehole through an external seepage hole (15) arranged on the rock mass riveting mechanism, so as to ensure that the noise reduction material is injected as a whole; the probe (18) is a structure with a T-shaped cross section composed of a horizontal plate and a vertical rod; A microseismic sensor high coupling mounting assembly, wherein the microseismic sensor high coupling mounting assembly comprises the microseismic sensor high coupling mounting assembly according to any one of claims 1 to 4; wherein: The inner sleeve (14) is placed on the partition (20); the horizontal plate of the probe (18) is connected to the lower part of the inner sleeve (14) and contacts the conductive bolt (1), and the connection position of the probe (18) in the height direction of the inner sleeve (14) is adjustable; the vertical rod of the probe (18) passes through the center of the partition (20) and is in close contact with the coupling hole (31) set at the center of the bottom of the rock riveting mechanism.

6. The high-coupling installation device for microseismic sensors in rock mass according to claim 5, characterized in that: The lower part of the inner sleeve (14) is provided with a spirally distributed retaining ring (23) along the height direction of the inner side wall; the horizontal plate edge of the probe rod (18) is provided with a buckle (27) that cooperates with the buckle (23), and the buckle (27) cooperates with the buckle (23) to realize the screwing in and out and position fixing of the probe rod (18) along the height direction of the inner sleeve (14).

7. The high-coupling installation device for microseismic sensors in rock mass according to claim 5, characterized in that: The rock mass riveting mechanism is formed by connecting a fixing cover (6), an outer sleeve (11), and a tip head (17) in sequence; the tip head (17) is a hollow cone structure, which is connected to the bottom end of the outer sleeve (11), and the two form an integrated structure with a hollow interior; the fixing cover (6) is installed on the top end of the outer sleeve (11), and a pre-tightening bolt (7) is installed on the fixing cover (6), so as to facilitate drilling the rock mass riveting mechanism into the rock mass at the bottom of the borehole.

8. The high-coupling installation device for microseismic sensors in rock mass according to claim 7, characterized in that: The outer sleeve (11) and the pointed head (17) are provided with continuous external threads (10), which facilitate drilling into the rock mass at the bottom of the borehole.

9. The high-coupling installation device for microseismic sensors in rock mass according to claim 7, characterized in that: A plurality of external leakage holes (15) are arranged on the side wall of the pointed tip (17), and a spacer is arranged at the external port of the external leakage hole (15).

10. The high-coupling installation device for microseismic sensors in rock mass according to claim 7, characterized in that: The partition plate (20) is connected inside the outer sleeve (11) and is located at the lower end of the outer sleeve (11); the slurry chamber (19) is formed between the partition plate (20), the outer sleeve (11) and the pointed end (17).

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