220kv rated voltage cross-linked polyethylene insulation smooth aluminum sheath polyethylene sheath power cable and production equipment

Abstract

The utility model relates to power cable technical field, and disclose the rated voltage 220kV cross -linked polyethylene insulation smooth aluminium cover polyethylene sheath power cable, including split conductor. The rated voltage 220kV cross -linked polyethylene insulation smooth aluminium cover polyethylene sheath power cable, split conductor structure is five split unit stranding structure, and 2500mm conductor structure is adopted 5 fan -shaped strand blocks stranding with water -resisting function, and the central angle of fan -shaped strand block is 72, and the final outer diameter of conductor is 61.5±0.5mm, and the elongation of any single wire is not less than 30%, and the semi -conductive water -resisting bale is made of semi -conductive special dragon belt + non -woven fabric, and the thickness is 0.3mm, and the width is 35mm, and the coverage of wrapping is 15%, and the water -resisting performance of cable is strengthened, and the conductor shielding layer adopts semi -conductive polyolefin mixture and is extruded and is wrapped up and constitutes, and the average thickness of inner shielding layer is 2.0mm.

Description

Technical Field

[0001] This utility model relates to the field of power cable technology, specifically to a 220kV cross-linked polyethylene insulated, smooth aluminum-sheathed, polyethylene-sheathed power cable and its production equipment. Background Technology

[0002] In the field of high-voltage power transmission, power cables with a rated voltage of 220kV undertake important tasks of power transmission. With the continuous development of power grid construction, higher requirements are placed on the performance, reliability and production efficiency of power cables of this voltage level.

[0003] Traditional 220kV power cables struggle to achieve the optimal balance between insulation performance, mechanical properties, and environmental resistance. For example, the insulation layer is prone to partial discharge under long-term high voltage, affecting the cable's service life. The cable's mechanical strength is insufficient, and its internal structure may be damaged by external forces during laying and operation.

[0004] The production of 220kV cross-linked polyethylene insulated smooth aluminum sheathed polyethylene power cables requires multiple processing steps, such as cable cutting. Cutting equipment is needed for this process, but traditional cutting equipment has poor cutting and positioning capabilities, making it difficult to effectively limit the cable in actual use. Often, manual intervention is required to limit and fix the cable before cutting, increasing manual labor and reducing cutting efficiency. Utility Model Content

[0005] Technical problem to be solved: The purpose of this utility model is to provide a 220kV cross-linked polyethylene insulated smooth aluminum-sheathed polyethylene power cable and production equipment, so as to solve the problems mentioned in the background art that the existing traditional 220kV power cable is difficult to achieve the best balance in terms of insulation performance, mechanical performance and environmental resistance performance, as well as the problem that the traditional production and cutting equipment has poor cutting and positioning ability when in use.

[0006] Technical Solution: To achieve the above objectives, this utility model provides the following technical solution: a 220kV cross-linked polyethylene insulated, smooth aluminum-sheathed, polyethylene-coated power cable, comprising a segmented conductor, characterized in that: the segmented conductor structure is a five-segment stranded structure, the 2500mm conductor structure is formed by stranding five fan-shaped strands with water-blocking function, the center angle of the fan-shaped strands is 72°, the final outer diameter of the conductor is 61.5±0.5mm, the breaking elongation of any single strand is not less than 30%, and the outer end of the segmented conductor is provided with a semi-conductive water-resistant wrapping tape. It is made of semi-conductive terylene tape and non-woven fabric, with a thickness of 0.3mm and a width of 35mm. The coverage of the wrapping is 15%, which enhances the water resistance of the cable. The outer end of the semi-conductive water-resistant tape is provided with a conductor shielding layer. The conductor shielding layer is extruded from a semi-conductive polyolefin mixture. The average thickness of the inner shielding layer is 2.0mm. The outer end of the conductor shielding layer is provided with an insulation layer. The insulation layer is extruded from cross-linked polyethylene material. The insulation eccentricity of the insulation layer is less than 3%. The nominal thickness of the insulation layer is 24.0mm, and the thinnest point thickness is 22.80mm (95%).

[0007] Preferably, an outer shielding layer is provided at the outer end of the insulating layer. The outer shielding layer is formed by extruding a semi-conductive polyolefin mixture and has an average thickness of 1.0 mm. A semi-conductive shielding layer is provided at the outer end of the outer shielding layer. The semi-conductive shielding layer is formed by overlapping and wrapping two layers of semi-conductive buffer water-blocking tape. The overlap rate of the overlapping and wrapping of the semi-conductive buffer water-blocking tape is 48% to 50%, and the average thickness of the semi-conductive buffer water-blocking tape is 2.0 mm, with a nominal width of 80 mm.

[0008] Preferably, the outer end of the semiconductive shielding layer is provided with an aluminum tube. The aluminum tube is made of flat aluminum sleeve + hot melt adhesive and is constructed by longitudinal welding. The thickness of the aluminum tube is 2.8mm. It is rolled continuously to reduce its diameter and is in close contact with the water-blocking and buffering semiconductive shielding layer. The rolling continuous diameter reduction process of the aluminum tube ensures good electrical performance contact. The outer diameter is small and the material usage is small. The outside of the smooth aluminum tube is covered with hot melt adhesive, which makes the aluminum tube and the sheath fully bonded and not separated. The outer end of the aluminum tube is provided with a non-metallic sheath. The non-metallic sheath is made of polyethylene outer sheath + graphene material. The non-metallic sheath is made of halogen-free, low-smoke, high electrical performance insulation grade sheath material with a strength of 13.5Mpa, an elongation of 450%, and reaches the flame retardant A level.

[0009] Preferably, the cable and production equipment include a workbench, characterized in that: a PLC controller is fixedly installed on one side of the workbench, a gantry support frame is fixedly installed on the top of the workbench, a hydraulic cylinder is fixedly installed on the top of the gantry support frame, the hydraulic cylinder is electrically connected to the PLC controller, a support connecting plate is fixedly installed on the output shaft end of the hydraulic cylinder, and a cutting blade is fixedly installed on the bottom end of the support connecting plate.

[0010] Preferably, the top of the gantry support frame has two guide holes, the top of the support connecting plate has two limiting slide rods fixedly installed, the limiting slide rods extend through the guide holes to the top of the gantry support frame, and the top of the equipment workbench has a cutting support seat fixedly installed, the cutting support seat corresponding to the cutting blade.

[0011] Preferably, positioning collars are fixedly installed on both sides of the top of the equipment workbench, a first bracket is fixedly installed on one side of the top of the equipment workbench, a second bracket is fixedly installed on the side of the top of the equipment workbench away from the first bracket, a drive motor is fixedly installed on the side of the second bracket away from the first bracket, the drive motor is electrically connected to the PLC controller, and a first rubber shaft is fixedly installed on the output shaft end of the drive motor, the side of the first rubber shaft away from the drive motor is rotatably connected to one side of the first bracket.

[0012] Preferably, the first bracket and the second bracket have limit grooves on their adjacent sides. An electric push rod is fixedly installed on the top of the first bracket and the second bracket. The electric push rod is electrically connected to the PLC controller. The electric push rod extends into the interior of the limit groove. A support limit block is fixedly installed on the output shaft end of the electric push rod. A second rubber shaft is rotatably connected between the support limit blocks.

[0013] Compared with the prior art, the beneficial effects of this utility model are: 1. This 220kV cross-linked polyethylene insulated smooth aluminum-sheathed polyethylene-coated power cable and its production equipment have a five-segment stranded conductor structure. The 2500mm conductor structure is formed by stranding five fan-shaped strands with water-blocking function. The center angle of the fan-shaped strands is 72°, the final outer diameter of the conductor is 61.5±0.5mm, and the breaking elongation of any single strand is not less than 30%. The semi-conductive water-blocking tape is made of semi-conductive terylene tape + non-woven fabric, with a thickness of 0.3mm and a width of 35mm. The coverage of the wrapping is 15%, which enhances the water-blocking performance of the cable. The conductor shielding layer is made of semi-conductive polyolefin mixture extrusion, with an average thickness of 2.0mm for the inner shielding layer. An insulation layer is provided at the outer end of the conductor shielding layer. The insulation layer is made of cross-linked polyethylene material extrusion, with an insulation eccentricity of less than 3%. The nominal thickness of the insulation layer is 24.0mm, and the thinnest point thickness is 22.80mm (95%). 2. The 220kV cross-linked polyethylene insulated smooth aluminum-sheathed polyethylene power cable and its production equipment have an outer shielding layer made of extruded semi-conductive polyolefin mixture with an average thickness of 1.0mm. The semi-conductive shielding layer is made of two layers of overlapping semi-conductive buffer water-blocking tape with an overlap rate of 48% to 50%. The average thickness of the semi-conductive buffer water-blocking tape is 2.0mm and the nominal width is 80mm. 3. The 220kV cross-linked polyethylene insulated smooth aluminum sheathed polyethylene power cable and its production equipment improve the positioning capability of this utility model by installing a positioning collar. In actual use, the cable to be cut is passed through the positioning collar and placed on the cutting support. Then, other winding equipment is used to wind or convey the cable, which can keep the cable always on the cutting support, making it easy to cut with the cutting blade without the need for manual limiting operation. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the cross-sectional structure of the cable of this utility model; Figure 2 This is a three-dimensional structural diagram of the production equipment of this utility model; Figure 3 This is a schematic diagram of a partial structure of the production equipment of this utility model. Figure 1 ; Figure 4 This is a schematic diagram of a partial structure of the production equipment of this utility model. Figure 2 .

[0015] In the diagram: 1. Dividing conductor; 2. Semiconductor resistive water-filled tape; 3. Conductor shielding layer; 4. Insulation layer; 5. Outer shielding layer; 6. Semiconductor shielding layer; 7. Aluminum tube; 8. Non-metallic sheath; 9. Equipment workbench; 10. PLC controller; 11. Gantry support frame; 12. Hydraulic cylinder; 13. Support connecting plate; 14. Cutting blade; 15. Guide through hole; 16. Limiting slide rod; 17. Cutting support seat; 18. Positioning collar; 19. First bracket; 20. Second bracket; 21. Drive motor; 22. First rubber shaft; 23. Limiting slide groove; 24. Electric push rod; 25. Support limiting block; 26. Second rubber shaft. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Please see Figures 1-4 This utility model provides a technical solution: a 220kV cross-linked polyethylene insulated smooth aluminum-sheathed polyethylene power cable, including a segmented conductor 1. The segmented conductor 1 has a five-segment stranded structure. The 2500mm conductor structure is formed by stranding five fan-shaped strands with water-blocking function. The center angle of the fan-shaped strands is 72°. The final outer diameter of the conductor is 61.5±0.5mm. The breaking elongation of any single strand is not less than 30%. The outer end of the segmented conductor 1 is provided with a semi-conductive water-resistant tape 2. The semi-conductive water-resistant tape 2 is made of semi-conductive terylene tape + non-woven fabric. Made of a semi-conductive water-resistant sheath 2, with a thickness of 0.3mm and a width of 35mm, the sheath has a coverage rate of 15%, enhancing the cable's water-blocking performance. A conductor shielding layer 3 is located at the outer end of the semi-conductive water-resistant sheath 2. The conductor shielding layer 3 is an inner shielding layer formed by extrusion of a semi-conductive polyolefin mixture, with an average thickness of 2.0mm. An insulation layer 4 is located at the outer end of the conductor shielding layer 3. The insulation layer 4 is extruded from cross-linked polyethylene material, with an insulation eccentricity of less than 3%. The nominal thickness of the insulation layer 4 is 24.0mm, and the thinnest point thickness is 22.80mm (95%). The outer end of the insulation layer 4... An outer shielding layer 5 is provided at one end. The outer shielding layer 5 is extruded from a semi-conductive polyolefin mixture and has an average thickness of 1.0 mm. A semi-conductive shielding layer 6 is provided at the outer end of the outer shielding layer 5. The semi-conductive shielding layer 6 is composed of two layers of semi-conductive buffer water-blocking tape overlapping and wrapped. The overlap rate of the overlapping wrapping of the semi-conductive buffer water-blocking tape is 48% to 50%, the average thickness of the semi-conductive buffer water-blocking tape is 2.0 mm, and the nominal width is 80 mm. An aluminum tube 7 is provided at the outer end of the semi-conductive shielding layer 6. The aluminum tube 7 is made of flat aluminum sleeve + hot melt adhesive and is constructed by longitudinal wrapping and welding. The aluminum tube 7 is 2.8mm thick and is made of continuously rolled and reduced diameter material, which is in close contact with the water-blocking and buffering semi-conductive shielding layer 6. The continuous rolling and reduction diameter process of the aluminum tube 7 ensures good electrical contact, small outer diameter, and less material usage. Hot melt adhesive is used on the outside of the smooth aluminum tube 7 to fully bond the aluminum tube 7 to the sheath and prevent separation. The outer end of the aluminum tube 7 is provided with a non-metallic sheath 8, which is made of polyethylene outer sheath + graphene material. The non-metallic sheath 8 uses halogen-free, low-smoke, high electrical performance insulation sheath material with a strength of 13.5Mpa, an elongation of 450%, and reaches the flame retardant A level.

[0018] A cable and production equipment are disclosed. The cable and production equipment include a workbench 9, a PLC controller 10 fixedly mounted on one side of the workbench 9, a gantry support frame 11 fixedly mounted on the top of the workbench 9, a hydraulic cylinder 12 fixedly mounted on the top of the gantry support frame 11, the hydraulic cylinder 12 being electrically connected to the PLC controller 10, a support connecting plate 13 fixedly mounted on the output shaft end of the hydraulic cylinder 12, a cutting blade 14 fixedly mounted on the bottom end of the support connecting plate 13, two guide holes 15 formed at the top of the gantry support frame 11, two limiting slide rods 16 fixedly mounted on the top of the support connecting plate 13, the limiting slide rods 16 extending through the guide holes 15 to the top of the gantry support frame 11, a cutting support seat 17 fixedly mounted on the top of the workbench 9, the cutting support seat 17 corresponding to the cutting blade 14, positioning collars 18 fixedly mounted on both sides of the top of the workbench 9, a first bracket 19 fixedly mounted on one side of the top of the workbench 9, and a second bracket 18 fixedly mounted on the side of the top of the workbench 9 away from the first bracket 19. A drive motor 21 is fixedly installed on the side of the second bracket 20 away from the first bracket 19. The drive motor 21 is electrically connected to the PLC controller 10. A first rubber shaft 22 is fixedly installed on the output shaft end of the drive motor 21. The side of the first rubber shaft 22 away from the drive motor 21 is rotatably connected to the side of the first bracket 19. Limiting grooves 23 are opened on the two sides of the first bracket 19 and the second bracket 20 that are close to each other. An electric push rod 24 is fixedly installed on the top of the first bracket 19 and the second bracket 20. The electric push rod 24 is electrically connected to the PLC controller 10 and extends into the interior of the limiting groove 23. A support limiting block 25 is fixedly installed on the output shaft end of the electric push rod 24. A second rubber shaft 26 is rotatably connected between the support limiting blocks 25. The cable to be cut is passed through the positioning collars 18 on both sides of the top of the equipment workbench 9. The positioning collars 18 play a preliminary positioning role. The electric push rod 24 pushes the support limiting block 25 to move within the limiting groove 23, thereby adjusting the height of the second rubber shaft 26.

[0019] Working Principle: The split conductor 1 has a five-segment stranded structure. The 2500mm conductor structure is composed of five fan-shaped strands with water-blocking function, with a center angle of 72°. The final outer diameter of the conductor is 61.5±0.5mm, and the breaking elongation of any single strand is not less than 30%. The semi-conductive water-blocking tape 2 is made of semi-conductive polyester tape + non-woven fabric, with a thickness of 0.3mm and a width of 35mm. The coverage of the wrapping is 15%, which enhances the water-blocking performance of the cable. The conductor shielding layer 3 is an inner shielding layer made of semi-conductive polyolefin mixture extruded with an average thickness of 2.0mm. The insulation layer 4 has an insulation eccentricity of less than 3%, a nominal thickness of 24.0mm, and a minimum thickness of 22.80mm (95%). The outer shielding layer 5 is also made of semi-conductive polyolefin mixture extruded. The outer shielding layer 5 has an average thickness of 1.0 mm. The semi-conductive shielding layer 6 is composed of two layers of overlapping semi-conductive buffer water-blocking tape. The overlap rate of the overlapping wrapping of the semi-conductive buffer water-blocking tape is 48% to 50%. The average thickness of the semi-conductive buffer water-blocking tape is 2.0 mm, and the nominal width is 80 mm. The aluminum tube 7 is made of flat aluminum sleeve + hot melt adhesive and is constructed by longitudinal welding. The thickness of the aluminum tube 7 is 2.8 mm. It is rolled continuously to reduce its diameter and is in close contact with the water-blocking and buffering semi-conductive shielding layer 6. The rolling continuous diameter reduction process of the aluminum tube 7 ensures good electrical contact, small outer diameter, and less material usage. The outside of the smooth aluminum tube 7 is covered with hot melt adhesive, which makes the aluminum tube 7 fully bonded to the sheath and prevents separation. The non-metallic sheath 8 is made of polyethylene outer sheath + graphene material. The non-metallic sheath 8 uses halogen-free, low-smoke, high electrical performance insulation grade sheath material with a strength of 13.With a strength of 5 MPa and an elongation of 450%, achieving flame retardant level A, this cable is cut during production. The cable is passed through positioning rings 18 on both sides of the top of the workbench 9. These positioning rings 18 provide initial positioning, ensuring the cable is stably placed on the cutting support 17. Simultaneously, one end of the cable is passed through the second rubber shaft 26 and the first rubber shaft 22, positioning it above the first rubber shaft 22. Depending on the needs, one end of the cable can be connected to other winding equipment for winding, or directly conveyed to other processing equipment for processing. Simultaneously, based on parameters such as the cable diameter, the electric push rod 24 is activated via the PLC controller 10. 24. The support limiting block 25 is moved within the limiting groove 23, thereby adjusting the height of the second rubber shaft 26. This allows the second rubber shaft 26 to engage with the first rubber shaft 22, enabling limited cable transmission without clamping. Then, the drive motor 21 is activated to rotate the first rubber shaft 22, which in turn rotates the cable with the second rubber shaft 26, facilitating cable transfer. This allows the cable to be transferred to other equipment for processing as needed. When cable cutting is required, the electric push rod 24 is activated again to lower the second rubber shaft 26 to clamp the cable, while simultaneously stopping the drive motor 21 to ensure cable stability. Then, the hydraulic cylinder 12 is activated to lower the support connecting plate 13 and the cutting blade 14, allowing the cutting blade 14 to cut the cable.

[0020] Finally, it should be noted that the above content is only used to illustrate the technical solution of this utility model, and is not intended to limit the scope of protection of this utility model. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of this utility model do not depart from the essence and scope of the technical solution of this utility model.

Claims

1. A 220kV cross-linked polyethylene insulated, smooth aluminum-sheathed, polyethylene-sheathed power cable, comprising a split conductor (1), characterized in that: The segmented conductor (1) has a five-segment stranded structure. The 2500mm conductor structure is formed by stranding five fan-shaped strands with water-blocking function. The center angle of the fan-shaped strands is 72°, the final outer diameter of the conductor is 61.5±0.5mm, and the breaking elongation of any single strand is not less than 30%. The outer end of the segmented conductor (1) is provided with a semi-conductive water-blocking wrapping tape (2). The semi-conductive water-blocking wrapping tape (2) is made of semi-conductive terylene tape + non-woven fabric, with a thickness of 0.3mm and a width of 35mm. The wrapping overlaps... The coverage rate is 15%, which enhances the water resistance performance of the cable. The outer end of the semi-conductive water-resistant tape (2) is provided with a conductor shielding layer (3). The conductor shielding layer (3) is made of semi-conductive polyolefin mixture extrusion. The average thickness of the inner shielding layer is 2.0 mm. The outer end of the conductor shielding layer (3) is provided with an insulation layer (4). The insulation layer (4) is extruded from cross-linked polyethylene material. The insulation eccentricity of the insulation layer (4) is less than 3%. The nominal thickness of the insulation layer (4) is 24.0 mm, and the thinnest point thickness is 22.80 mm.

2. The 220kV cross-linked polyethylene insulated smooth aluminum-sheathed polyethylene power cable according to claim 1, characterized in that: An outer shielding layer (5) is provided at the outer end of the insulating layer (4). The outer shielding layer (5) is formed by extruding a semi-conductive polyolefin mixture. The average thickness of the outer shielding layer (5) is 1.0 mm. A semi-conductive shielding layer (6) is provided at the outer end of the outer shielding layer (5). The semi-conductive shielding layer (6) is formed by overlapping and wrapping two layers of semi-conductive buffer water-blocking tape. The overlap rate of the overlapping and wrapping of the semi-conductive buffer water-blocking tape is 48% to 50%. The average thickness of the semi-conductive buffer water-blocking tape is 2.0 mm, and the nominal width is 80 mm.

3. The 220kV cross-linked polyethylene insulated smooth aluminum-sheathed polyethylene power cable according to claim 2, characterized in that: An aluminum tube (7) is provided at the outer end of the semiconductive shielding layer (6). The aluminum tube (7) is made of flat aluminum sleeve + hot melt adhesive and is constructed by longitudinal welding. The thickness of the aluminum tube (7) is 2.8 mm. It is rolled continuously to reduce the diameter and is in close contact with the water-blocking and buffering semiconductive shielding layer (6). The rolling continuous diameter reduction process of the aluminum tube (7) ensures good electrical performance contact. The outer diameter is small and the material is less. Hot melt adhesive is used on the outside of the smooth aluminum tube (7) so that the aluminum tube (7) and the sheath are fully bonded and do not separate. A non-metallic sheath (8) is provided at the outer end of the aluminum tube (7). The non-metallic sheath (8) is made of halogen-free, low-smoke, high electrical performance insulation grade sheath material with a strength of 13.5 MPa and an elongation of 450%, reaching the flame retardant A level.

4. The production equipment for 220kV cross-linked polyethylene insulated smooth aluminum sheathed polyethylene power cables according to claim 3, comprising a workbench (9), characterized in that: A PLC controller (10) is fixedly installed on one side of the equipment workbench (9). A gantry support frame (11) is fixedly installed on the top of the equipment workbench (9). A hydraulic cylinder (12) is fixedly installed on the top of the gantry support frame (11). The hydraulic cylinder (12) is electrically connected to the PLC controller (10). A support connecting plate (13) is fixedly installed on the output shaft end of the hydraulic cylinder (12). A cutting blade (14) is fixedly installed on the bottom end of the support connecting plate (13).

5. The production equipment for 220kV cross-linked polyethylene insulated smooth aluminum-sheathed polyethylene-coated power cables according to claim 4, characterized in that: The top of the gantry support frame (11) has two guide holes (15), and the top of the support connecting plate (13) has two limiting slide rods (16) fixedly installed. The limiting slide rods (16) extend through the guide holes (15) to the top of the gantry support frame (11). The top of the equipment workbench (9) has a cutting support seat (17) fixedly installed. The cutting support seat (17) corresponds to the cutting blade (14).

6. The production equipment for 220kV cross-linked polyethylene insulated smooth aluminum-sheathed polyethylene-coated power cables according to claim 5, characterized in that: Positioning collars (18) are fixedly installed on both sides of the top of the equipment workbench (9). A first bracket (19) is fixedly installed on one side of the top of the equipment workbench (9). A second bracket (20) is fixedly installed on the side of the top of the equipment workbench (9) away from the first bracket (19). A drive motor (21) is fixedly installed on the side of the second bracket (20) away from the first bracket (19). The drive motor (21) is electrically connected to the PLC controller (10). A first rubber shaft (22) is fixedly installed on the output shaft end of the drive motor (21). The side of the first rubber shaft (22) away from the drive motor (21) is rotatably connected to the side of the first bracket (19).

7. The production equipment for 220kV cross-linked polyethylene insulated smooth aluminum-sheathed polyethylene-coated power cables according to claim 6, characterized in that: Limiting grooves (23) are provided on the two sides of the first bracket (19) and the second bracket (20) that are close to each other. An electric push rod (24) is fixedly installed on the top of the first bracket (19) and the second bracket (20). The electric push rod (24) is electrically connected to the PLC controller (10). The electric push rod (24) extends into the interior of the limiting groove (23). A support limiting block (25) is fixedly installed on the output shaft end of the electric push rod (24). A second rubber shaft (26) is rotatably connected between the support limiting blocks (25).

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