Mine water reverse osmosis filtering device

Abstract

The present application relates to the technical field of water treatment, and aims at the problem that high-pressure container tubes and reverse osmosis membranes are difficult to be taken out from a rack for replacement, the present application provides a mine water reverse osmosis filtering device, which comprises a rack, the rack is provided with a plurality of placement areas, each placement area is slidably provided with a plurality of installation blocks, and each installation block is provided with a reverse osmosis component for reverse osmosis of pretreated mine water; the reverse osmosis component comprises a high-pressure container tube installed on the installation block, the high-pressure container tube is provided with a reverse osmosis membrane, one end of the high-pressure container tube is connected with a raw water inlet pipe, the other end of the high-pressure container tube is connected with a clean water outlet pipe, and the side wall of the high-pressure container tube is connected with a concentrated water outlet pipe, the concentrated water outlet pipe is installed on the side of the rack along the width direction, there is a spacing between adjacent installation blocks, and the spacing between adjacent high-pressure container tubes is greater than the width of the installation block. Through the above arrangement, the reverse osmosis membrane can be better taken out from the rack.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a mine water reverse osmosis filtering device. BACKGROUND

[0002] Coal mining areas in China are mainly distributed in water shortage areas such as East China, North China, Northeast China and Northwest China, and mine water treatment and reuse for production and life have become one of the main ways to solve water resource shortage in mining areas, and are also the specific requirements of the national energy saving and emission reduction policy and the Mine Water Utilization Special Planning and Mine Water Utilization Development Planning.

[0003] Generally, when treating mine water, a reverse osmosis filtering device is used to treat mine water. The reverse osmosis filtering device comprises a placing rack, a plurality of high-pressure container pipes are installed on the placing rack, a reverse osmosis filtering membrane is installed in the high-pressure container pipe, and a raw water inlet pipe and a clean water outlet pipe are respectively communicated with both ends of the high-pressure container pipe, and a concentrated water outlet pipe is communicated with the side wall of the high-pressure container pipe. When the reverse osmosis filtering device is used to treat mine water, the pretreated mine water is first input into the high-pressure container pipe from the raw water inlet pipe by a high-pressure pump, and after reverse osmosis filtration, the obtained clean water is output and discharged through the clean water outlet pipe, and the obtained concentrated water is output through the concentrated water outlet pipe and then enters the next reverse osmosis high-pressure container pipe as the raw water of the next reverse osmosis filtration container for filtration, thereby completing the reverse osmosis filtration of mine water.

[0004] After the reverse osmosis device is used for a period of time, a large number of microorganisms may breed on the reverse osmosis membrane, affecting the reverse osmosis filtration effect, so the reverse osmosis filtration membrane needs to be replaced from time to time, but since the high-pressure container pipe is generally long and pipes are arranged on both ends and the side wall of the high-pressure container pipe, the reverse osmosis membrane in the high-pressure container pipe is difficult to be taken out from the placing rack for replacement. SUMMARY

[0005] In view of the problem that the reverse osmosis membrane is difficult to be taken out from the placing rack for replacement due to the fact that the high-pressure container pipe is generally long and pipes are arranged on both ends and the side wall of the high-pressure container pipe, the present application provides a mine water reverse osmosis filtering device, which is beneficial to better taking out the reverse osmosis membrane from the placing rack.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] A mine water reverse osmosis filtering device comprises a placing rack, the placing rack is provided with a plurality of placing areas, each placing area is slidably installed with a plurality of installation blocks, and each installation block is provided with a reverse osmosis component for reverse osmosis of pretreated mine water.

[0008] The reverse osmosis device comprises a high-pressure container pipe mounted on the mounting block, a reverse osmosis membrane for filtering mine water by reverse osmosis is arranged in the high-pressure container pipe, one end of the high-pressure container pipe is detachably connected with a raw water inlet pipe, the other end of the high-pressure container pipe is detachably connected with a clean water outlet pipe, a concentrated water outlet pipe is detachably connected with the side wall of the high-pressure container pipe, and the concentrated water outlet pipe is mounted on the side of the placing rack along the width direction, a spacing is arranged between adjacent mounting blocks, and the spacing between adjacent mounting blocks is greater than the width of the mounting block.

[0009] According to the technical scheme, when a reverse osmosis membrane needs to be replaced, an operator detaches the corresponding raw water inlet pipe, clean water outlet pipe and concentrated water outlet pipe, then moves the mounting block with the reverse osmosis membrane to be replaced towards the direction of the adjacent mounting block, avoids the pipeline obstacle, and then takes the mounting block out of the placing rack. The above arrangement is beneficial to taking the reverse osmosis membrane out of the placing rack. Meanwhile, the time for maintaining and replacing the reverse osmosis device is reduced, the downtime of the process equipment during maintenance and replacement is reduced, and the efficiency of mine water treatment is improved.

[0010] Preferably, the bottom of each placing area is provided with a bearing plate for placing the mounting block, the bearing plate is in sliding connection with the mounting block, and the top wall of the mounting block is recessed with a mounting groove for mounting the high-pressure container pipe.

[0011] According to the technical scheme, the high-pressure container pipe is mounted in the mounting block through the mounting groove, so that the high-pressure container pipe can be stably arranged in the placing area after being mounted, and even if the connected pipeline is detached, the high-pressure container pipe is not easy to move or roll on the bearing plate due to the loss of support, the safety risk caused by the movement or rolling of the high-pressure container pipe is reduced, and the safety of operation is improved.

[0012] Preferably, the mounting block is provided with a fixing member for fixing the high-pressure container pipe.

[0013] According to the technical scheme, during the operation of the reverse osmosis filtering device, the high-pressure container pipe needs to withstand high pressure inside, and the fixing member is arranged to provide stable fixation and support for the high-pressure container pipe, so as to prevent the high-pressure container pipe from moving or vibrating due to high pressure, thereby ensuring the stability of the high-pressure container pipe and reducing the damage of the high-pressure container pipe caused by vibration or displacement. When the reverse osmosis membrane is maintained or replaced, the mounting block needs to be driven to move, and the fixing member can reduce the accidental movement or falling of the high-pressure container pipe during the movement of the mounting block, thereby reducing the safety risk in operation.

[0014] Preferably, the fixing member comprises a magnetic sheet arranged on the groove wall of the mounting groove, and the outer wall of the high-pressure container pipe is provided with a connecting cylinder made of iron.

[0015] By means of the magnetic fixing member, the high-pressure container pipe can be kept stable even under high pressure or vibration, the movement and vibration of the pipe are reduced, and the service life of the equipment is prolonged; when the reverse osmosis membrane needs to be maintained or replaced, the magnetic fixing member enables the operator to easily remove and install the high-pressure container pipe without using additional tools, thereby reducing the maintenance time and complexity and reducing the economic loss caused by long-term shutdown.

[0016] Preferably, the groove wall of the mounting groove is provided with a plurality of rubber blocks away from the groove bottom, the rubber blocks are semispherical, the plurality of rubber blocks are uniformly distributed on the groove wall of the mounting groove, the groove wall of the mounting groove is recessed with a sliding groove for sliding connection of the rubber blocks, and the sliding groove is provided with a first elastic member for driving the rubber blocks to move away from the bottom of the sliding groove at all times.

[0017] By means of the above technical scheme, when the high-pressure container pipe is installed in the mounting block, the first elastic member drives the rubber blocks to protrude from the sliding groove, so that the rubber blocks continuously abut against the high-pressure container pipe, and the stability of the high-pressure container pipe on the placing rack is further improved; at the same time, when the high-pressure container pipe needs to be installed or disassembled, the high-pressure container pipe is driven to move away from or close to the bottom of the mounting groove, the high-pressure container pipe drives the rubber blocks to move towards the bottom of the sliding groove, so that the rubber blocks are placed in the sliding groove, thereby preventing the rubber blocks from affecting the installation or disassembly of the high-pressure container pipe, and the rubber blocks can further stabilize the high-pressure container pipe without hindering the installation and disassembly of the high-pressure container pipe.

[0018] Preferably, the mounting block is further provided with a stabilizing member for continuously stabilizing the mounting block in a horizontal position, and the stabilizing member stabilizes the mounting block by increasing the support force of the mounting block.

[0019] By means of the above technical scheme, the stabilizing member is provided, which is beneficial to reduce the situation that when the mounting block is moved out of the placing rack, due to the long length of the mounting block, one end of the mounting block is easily inclined downward, which may cause the other end to move upward, resulting in collision between the mounting block and the high-pressure container pipe located in the placing rack and the bearing plate of the upper layer, thereby easily causing damage to the mounting block, the high-pressure container pipe and the bearing plate; the stabilizing member ensures that the mounting block can maintain a horizontal state during movement, reduces the upward movement or damage caused by inclination; at the same time, the stabilizing member not only protects the equipment, but also reduces the risk of injury to the operator caused by improper movement of the mounting block.

[0020] Preferably, the stabilizing piece is a connecting rod arranged at one end of the mounting block, one side of the load-bearing plate is recessed with a connecting groove, the connecting rod extends towards the connecting groove, and the end of the connecting rod away from the mounting block is slidably connected with the groove bottom of the connecting groove, the connecting rod is provided with a horizontal section, a vertical section and an extension section connected in sequence, and the extension section is located in the connecting groove.

[0021] By arranging the connecting rod and the connecting groove, the connection between the mounting block and the load-bearing plate is improved, the connecting rod provides support for the mounting block, so that the end of the mounting block is not easily tilted downward due to gravity when the mounting block is removed from the rack, and the upward movement or damage caused by the tilt is reduced.

[0022] Preferably, the extension section is provided with a second elastic piece that always drives the extension section to extend towards the groove bottom of the connecting groove.

[0023] When the reverse osmosis membrane is replaced, the second elastic piece drives the mounting block to move towards the rack, so that the mounting block can automatically move to the appropriate position, reducing the manual adjustment process, simplifying the replacement operation, and making it easier for maintenance personnel to maintain the device.

[0024] In summary, the present application has the following advantages:

[0025] 1. By arranging the spacing between adjacent high-pressure container tubes, the load-bearing plate, the mounting block and the mounting groove, the reverse osmosis membrane can be better removed from the rack; at the same time, the high-pressure container tube can be stably installed in the placement area after installation, and even if the connected pipeline is disassembled, it is not easy to move or roll on the load-bearing plate due to the loss of support, increasing the safety of the operation.

[0026] 2. By arranging the magnetic sheet, the connecting cylinder, the rubber block and the first elastic piece, the high-pressure container tube can remain stable even under high pressure or vibration, reducing the movement and vibration of the pipeline, thereby prolonging the service life of the equipment; at the same time, it also does not affect the difficulty of the operator to install and disassemble the high-pressure container tube.

[0027] 3. By arranging the connecting rod and the connecting groove, the connection between the mounting block and the load-bearing plate is improved, and the upward movement or damage caused by the tilt is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a schematic view of the overall structure of a mine water reverse osmosis filtration device according to an embodiment of the present application.

[0029] Figure 2 is Figure 1 an enlarged structural schematic view of part A in

[0030] Figure 3 is a whole structure schematic view of a mounting block in a mine water reverse osmosis filtering device.

[0031] Figure 4 is Figure 3 is an enlarged structure schematic view of B part in

[0032] Explanation of reference signs:

[0033] 1, placing rack; 11, placing area; 21, high-pressure container tube; 22, raw water inlet pipe; 23, clean water outlet pipe; 24, concentrated water outlet pipe; 3, bearing plate; 31, mounting block; 32, mounting groove; 33, magnetic sheet; 34, connecting cylinder; 35, width groove; 36, length groove; 37, rubber block; 38, sliding groove; 5, stabilizing piece; 51, horizontal section; 52, vertical section; 53, telescopic section; 531, telescopic rod; 532, fixed rod; 54, connecting groove; 55, second elastic piece. Specific implementation

[0034] The application is further described in detail below in combination with the drawings and examples.

[0035] The embodiment of the application provides a mine water reverse osmosis filtering device, referring to Figure 1, including the rack 1, the rack 1 is equipped with three placement area 11, the bottom of the placement area 11 is fixedly connected with the load-bearing plate 3 for placing reverse osmosis, the top wall of each load-bearing plate 3 is slidably connected with two mounting blocks 31 for mounting high-pressure container, and there is a spacing between the two mounting blocks 31 on the same load-bearing plate 3, and the spacing between the adjacent mounting blocks 31 is greater than the width of the mounting block 31. The mounting block 31 is provided with a reverse osmosis device for reverse osmosis of pretreated mine water, and each mounting block 31 is provided with one reverse osmosis device. The reverse osmosis device comprises a high-pressure container tube 21 mounted on the mounting block 31 and a reverse osmosis membrane arranged in the high-pressure container tube 21 for reverse osmosis filtration of mine water, one end of the high-pressure container tube 21 is detachably connected with a raw water inlet pipe 22, the raw water inlet pipe 22 is provided with two, each raw water inlet pipe 22 is communicated with three high-pressure container tubes 21 in vertical direction, the other end of the high-pressure container tube 21 is detachably connected with a clean water outlet pipe 23, the clean water outlet pipe 23 is provided with two, each clean water outlet pipe 23 is communicated with three high-pressure container tubes 21 in vertical direction, the side wall of the high-pressure container tube 21 is detachably connected with a concentrated water outlet pipe 24, the concentrated water outlet pipe 24 is provided with two, each concentrated water outlet pipe 24 is communicated with three high-pressure container tubes 21 in vertical direction, and the concentrated water outlet pipe 24 is installed on both sides of the rack 1 along the width direction. When it is necessary to replace a certain reverse osmosis membrane, the operator first detaches the raw water inlet pipe 22, the clean water outlet pipe 23 and the concentrated water outlet pipe 24 connected with the high-pressure container tube 21, then pushes the mounting block 31 to move towards the adjacent mounting block 31, avoids the clean water outlet pipe 23 and the raw water inlet pipe 22, drives the mounting block 31 to move towards one end of the rack 1 in the length direction, moves the mounting block 31 out of the rack 1, then replaces the high-pressure container tube 21 or the reverse osmosis membrane, moves the mounting block 31 back to the rack 1, finally installs the raw water inlet pipe 22, the clean water outlet pipe 23 and the concentrated water outlet pipe 24, thereby completing the maintenance and replacement of the reverse osmosis membrane, and the above-mentioned arrangement is beneficial to the better extraction of the reverse osmosis membrane from the rack 1.

[0036] Referring to Figure 2 The bottom of the mounting block 31 is uniformly protruded with a plurality of sliding blocks, and the sliding blocks on each mounting block 31 are located on the same straight line, the top of the load-bearing plate 3 is recessed with a width groove 35 for the sliding block to move along the width direction of the load-bearing plate 3, and the top of the load-bearing plate 3 is also recessed with a length groove 36 for the sliding block to move along the length direction of the load-bearing plate 3, the length groove 36 intersects with the width groove 35, and the length groove 36 is located between the adjacent two mounting blocks 31 of the same placement area 11.

[0037] Referring to Figure 2 and Figure 4The top wall of the mounting block 31 is recessed with a mounting groove 32 for mounting the high-pressure container tube 21, and the mounting block 31 is provided with a fixing member for fixing the high-pressure container tube 21. The fixing member includes a magnetic sheet 33 arranged on the groove wall of the mounting groove 32 and a connecting cylinder 34 fixedly connected to the outer sidewall of the high-pressure container tube 21. In this embodiment, the connecting cylinder 34 is made of iron. When the high-pressure container tube 21 is mounted on the mounting groove 32, the connecting cylinder 34 is fixedly attracted by the magnetic force of the magnetic sheet 33, so that the high-pressure container tube 21 can be stably mounted on the mounting groove 32.

[0038] Referring to Figure 3 and Figure 4 The groove wall of the mounting groove 32 is slidingly connected with a plurality of rubber blocks 37 at a position away from the groove bottom, and the plurality of rubber blocks 37 are uniformly distributed on the groove wall of the mounting groove 32. The rubber blocks 37 are in a semispherical shape, and the groove wall of the mounting groove 32 is recessed with a sliding groove 38 for slidingly connecting the rubber blocks 37. The sliding groove 38 is provided with a first elastic member for always driving the rubber blocks 37 to move away from the groove bottom of the sliding groove 38. In this embodiment, the first elastic member is a spring, one end of the first elastic member is fixedly connected with the sidewall of the rubber block 37, and the other end of the first elastic member away from the rubber block 37 is fixedly connected with the groove bottom of the sliding groove 38. When the first elastic member is in a natural state, the rubber block 37 partially protrudes from the sliding groove 38. When the high-pressure container tube 21 is placed on the mounting groove 32, the first elastic member drives the rubber block 37 to move away from the groove bottom of the sliding groove 38, so that the rubber block 37 continuously abuts against the high-pressure container tube 21, and the high-pressure container tube 21 is more stable. When the high-pressure container tube 21 is mounted, the high-pressure container tube 21 extrudes the rubber block 37 and pushes the rubber block 37 to move toward the groove bottom of the sliding groove 38, so that the rubber block 37 does not easily affect the mounting of the high-pressure container tube 21.

[0039] Referring to Figure 3 and Figure 4The mounting block 31 is further provided with a stabilizer 5 for continuously stabilizing the mounting block 31 in a horizontal position, the stabilizer 5 stabilizes the mounting block 31 by adding a support force to the mounting block 31. The stabilizer 5 is a connecting rod arranged at one end of the mounting block 31 along the length direction, the load-bearing plate 3 is recessed with a connecting groove 54 at the side close to the purified water outlet pipe 23, the connecting rod extends in a curved manner towards the connecting groove 54, and the end of the connecting rod away from the mounting block 31 is slidably connected with the groove bottom of the connecting groove 54. The connecting rod is provided with a horizontal section 51, a vertical section 52 and an expansion section 53 connected in sequence, one end of the horizontal section 51 is fixedly connected with the side of the load-bearing plate 3 close to the purified water outlet pipe 23, one end of the expansion section 53 is slidably connected with the groove bottom of the connecting groove 54, and the expansion section 53 is located in the connecting groove 54. When the mounting block 31 is driven to move towards the adjacent mounting block 31, the expansion section moves along with the movement of the mounting block 31, and when the mounting block 31 is driven to move out of the placing rack 1, the expansion section expands, so that the stabilizer 5 provides a support force for the mounting block 31, and the mounting block 31 can be kept in a horizontal position during movement, thereby reducing the upward movement or damage caused by inclination.

[0040] Referring to Figure 4 The expansion section 53 comprises a fixed rod 532 and an expansion rod 531 slidably connected with the fixed rod 532, one end of the fixed rod 532 is slidably connected with the groove bottom of the connecting groove 54, and the expansion section 53 is provided with a second elastic member 55 for continuously driving the expansion section 53 to expand towards the groove bottom of the connecting groove 54. In this embodiment, the second elastic member 55 is a spring, one end of the second elastic member 55 is fixedly connected with the outer side wall of the fixed rod 532, and the other end of the second elastic member 55 is fixedly connected with the outer side wall of the expansion rod 531. When the high-pressure container pipe 21 or the reverse osmosis membrane is replaced, the second elastic member 55 drives the mounting block 31 to move towards the placing rack 1, and the mounting block 31 can automatically move to a proper position, thereby reducing the manual adjustment process and simplifying the replacement operation.

[0041] The implementation principle of this embodiment is as follows:

[0042] When it is necessary to replace a certain reverse osmosis membrane, the operator first dismounts the raw water inlet pipe 22, the purified water outlet pipe 23 and the concentrated water outlet pipe 24 corresponding to the high-pressure container tube 21 with the reverse osmosis membrane to be replaced, then drives the high-pressure container tube 21 with the reverse osmosis membrane to be replaced to move towards the adjacent high-pressure container tube 21, so that the slider moves along the width groove 35, the mounting block 31 with the reverse osmosis membrane to be replaced moves towards the adjacent mounting block 31, the mounting block 31 avoids the purified water outlet pipe 23, then drives the mounting block 31 to move out to the placing rack 1, the slider moves along the length groove 36, and the telescopic section 53 extends, then takes out the high-pressure container tube 21 with the reverse osmosis membrane to be replaced from the mounting block 31, replaces the reverse osmosis membrane, then puts the high-pressure container tube 21 with the replaced reverse osmosis membrane back to the mounting block 31, loosens the mounting block 31 with the replaced reverse osmosis membrane, the second elastic member 55 drives the mounting block 31 with the replaced reverse osmosis membrane to move back to the placing rack 1, then drives the mounting block 31 with the replaced reverse osmosis membrane to move away from the adjacent mounting block 31, and finally corresponds to mount the raw water inlet pipe 22, the purified water outlet pipe 23 and the concentrated water outlet pipe 24, so as to complete the replacement of the reverse osmosis membrane or the high-pressure container tube 21.

[0043] The embodiments of the specific implementation are the preferred embodiments of the present application, and do not limit the protection scope of the present application, so that: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A mine water reverse osmosis filtration apparatus, characterised in that: The utility model provides a kind of pre-treatment of mine water reverse osmosis device, including placing rack (1), the placing rack (1) is equipped with several placing area (11), each placing area (11) is slidably installed with several mounting blocks (31), each mounting block (31) is equipped with for the reverse osmosis of pre-treatment of mine water and is carried out reverse osmosis piece;The reverse osmosis piece includes the high-pressure container pipe (21) installed on the mounting block (31), the high-pressure container pipe (21) is equipped with for the reverse osmosis membrane of reverse osmosis filtering mine water in, one end of the high-pressure container pipe (21) is detachably connected with raw water inlet pipe (22), the other end of the high-pressure container pipe (21) is detachably connected with clean water outlet pipe (23), the sidewall of the high-pressure container pipe (21) is detachably connected with concentrated water outlet pipe (24), and the concentrated water outlet pipe (24) is installed on the side of the placing rack (1) along width direction, there is spacing between adjacent mounting blocks (31), and the spacing between adjacent mounting blocks (31) is greater than the width of the mounting block (31); The bottom of each placing area (11) is provided with a load-bearing plate (3) for placing the mounting block (31), the load-bearing plate (3) is slidably connected with the mounting block (31), and the top wall of the mounting block (31) is recessed with a mounting groove (32) for mounting the high-pressure container pipe (21); the mounting block (31) is provided with a fixing member for fixing the high-pressure container pipe (21); the mounting block (31) is further provided with a stabilizing member (5) for continuously stabilizing the mounting block (31) in a horizontal position, which stabilizes the mounting block (31) by increasing the support force of the mounting block (31); The bottom of the mounting block (31) is uniformly protruded with a plurality of sliding blocks, and the sliding blocks on each mounting block (31) are located on the same straight line. The top of the load-bearing plate (3) is recessed with a width groove (35) for the sliding blocks to move along the width direction of the load-bearing plate (3). The top of the load-bearing plate (3) is also recessed with a length groove (36) for the sliding blocks to move along the length direction of the load-bearing plate (3). The length groove (36) intersects with the width groove (35), and the length groove (36) is located between the adjacent two mounting blocks (31) of the same placing area (11).

2. The mine water reverse osmosis filtering device according to claim 1, characterized in that: The fixing member includes a magnetic sheet (33) provided on the groove wall of the mounting groove (32), and the outer sidewall of the high-pressure container pipe (21) is provided with a connecting cylinder (34) made of iron.

3. The mine water reverse osmosis filtering device according to claim 2, characterized in that: The groove wall of the mounting groove (32) is provided with a plurality of rubber blocks (37) away from the groove bottom. The rubber blocks (37) are semi-spherical. The rubber blocks (37) are evenly distributed on the groove wall of the mounting groove (32). The groove wall of the mounting groove (32) is recessed with a sliding groove (38) for the sliding connection of the rubber blocks (37). The sliding groove (38) is provided with a first elastic member for driving the rubber blocks (37) to move away from the groove bottom of the sliding groove (38) at all times. When the first elastic member is in a natural state, the rubber blocks (37) partially protrude from the sliding groove (38).

4. The mine water reverse osmosis filtering device according to claim 1, characterized in that: The stabilizing piece (5) is a connecting rod arranged at one end of the mounting block (31), one side of the load bearing plate (3) is recessed with a connecting groove (54), the connecting rod extends towards the direction of the connecting groove (54), and the end of the connecting rod away from the mounting block (31) is in sliding connection with the groove bottom of the connecting groove (54), the connecting rod is provided with a horizontal section (51), a vertical section (52) and an expansion section (53) connected in sequence, and the expansion section (53) is located in the connecting groove (54).

5. The mine water reverse osmosis filtering device according to claim 4, characterized in that: The expansion section (53) is provided with a second elastic piece (55) always driving the expansion section (53) to expand towards the groove bottom of the connecting groove (54).

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