Aluminum alloy heat treatment heating equipment device with precise temperature control

Abstract

The utility model relates to the field of aluminium alloy heat treatment, and disclose a kind of aluminium alloy heat treatment heating equipment device of precision temperature control, including resistance furnace, the furnace door one side of resistance furnace is equipped with multiple parameter cooling structure, multiple parameter cooling structure upper is equipped with clamping structure, the side of resistance furnace away from furnace door is equipped with push material structure, increase multiple parameter cooling structure, set up multiple different cooling areas in cooling box, cover multiple cooling modes such as water cooling, oil cooling, air cooling, by the ingenious cooperation of motor, screw rod, slider, cooling mode can be switched automatically, accurately according to preset cooling process, push material structure is automatically pushed to cooling box after the workpiece of heating, clamping structure is also automatically clamped workpiece after cooling is completed, avoid the knock and oxidation caused by artificial operation, heating, cooling and material handling structure are closely matched by preset program, realize accurate cooperation.

Description

Technical Field

[0001] This utility model relates to the field of aluminum alloy heat treatment, specifically to a heating device for precise temperature control in aluminum alloy heat treatment. Background Technology

[0002] In the production and processing of aluminum alloys, heat treatment is a key step in improving their performance. Through heat treatment, the mechanical properties, corrosion resistance and processing performance of aluminum alloys can be significantly improved. Therefore, the temperature control accuracy of heating equipment is very strict, and any temperature deviation may affect the final performance of the aluminum alloy.

[0003] Traditional aluminum alloy heat treatment equipment typically only offers a single cooling method, failing to flexibly adapt to the needs of different materials and processes. Even when some equipment offers multiple cooling options, its complex cooling structure and switching process still require manual intervention, resulting in cumbersome and time-consuming operation, reduced production efficiency, and potential impact on heat treatment quality due to untimely switching. Furthermore, existing equipment lacks effective protection mechanisms when transferring aluminum alloy workpieces from the heating furnace to the cooling device, making them prone to collisions and oxidation, affecting surface quality and performance. Simultaneously, the lack of effective coordination mechanisms between various heating, cooling, and material handling structures makes precise coordination difficult, further reducing overall operating efficiency. To address these issues, we propose a precise temperature-controlled aluminum alloy heat treatment heating device. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a precise temperature-controlled heating device for aluminum alloy heat treatment, thus solving the aforementioned problems.

[0005] To achieve the above-mentioned objectives, this utility model provides the following technical solution: a heating device for precise temperature control of aluminum alloy heat treatment, including a resistance furnace, wherein a multi-parameter cooling structure is provided on one side of the furnace door of the resistance furnace, a clamping structure is provided above the multi-parameter cooling structure, and a pushing structure is provided on the side of the resistance furnace away from the furnace door.

[0006] Preferably, the multi-parameter cooling structure includes a support frame, a motor, a lead screw, a slider, a sliding hole, and a limiting block. The support frame is fixedly connected to one side of the furnace door of the resistance furnace. The open side of the support frame is fixedly connected to the resistance furnace. A motor is fixedly connected to one side of the support frame. The main body of the motor is fixedly connected to the support frame. The output shaft of the motor passes through the support frame and is rotatably connected to it. One end of the motor's output shaft is fixedly connected to a lead screw via a coupling. The other end of the lead screw is rotatably connected to the inner wall of the support frame away from the motor. A sliding hole is formed through the top surface of the support frame. The centerline of the long side of the sliding hole is parallel to the axis of the lead screw. A threaded hole is formed through one side of the slider. The threaded hole of the slider is threadedly connected to the lead screw. A limiting block is fixedly connected to the side of the slider opposite to the sliding hole. The limiting block passes through the sliding hole and is slidably connected to the sliding hole.

[0007] Preferably, the multi-parameter cooling structure further includes a cooling box and partitions. The side of the limiting block away from the slider is fixedly connected to the cooling box, and the side of the cooling box away from the opening is fixedly connected to the limiting block. The opening side of the cooling box is flush with the bottom surface of the furnace chamber of the resistance furnace. Multiple partitions are fixedly connected inside the cooling box, and the partitions divide the interior of the cooling box into multiple parts.

[0008] Preferably, a mesh plate is fixedly connected to one of the portions of the cooling box that is separated by a partition. The mesh side of the mesh plate is parallel to the opening side of the cooling box, and a fan is installed between the side of the mesh plate away from the opening of the cooling box and the cooling box.

[0009] Preferably, the clamping structure includes a C-shaped bracket, an L-shaped bracket, a second hydraulic cylinder, and a clamping assembly. The top surface of the bracket frame is fixedly connected to the C-shaped bracket. The two ends of the two symmetrical folded edges of the C-shaped bracket are fixedly connected to the bracket frame. The side of the C-shaped bracket facing away from the bracket frame is fixedly connected to the L-shaped bracket. One end of one folded edge of the L-shaped bracket is fixedly connected to the C-shaped bracket. The side of the L-shaped bracket opposite to the bracket frame is fixedly connected to the second hydraulic cylinder. The bottom surface of the main body of the second hydraulic cylinder is fixedly connected to the C-shaped bracket. The side of the main body of the second hydraulic cylinder with the piston rod is fixedly connected to the side of the C-shaped bracket facing away from the bracket frame. The piston rod of the second hydraulic cylinder passes through the bracket frame and the second hydraulic cylinder is slidably connected to the bracket frame. A clamping assembly is installed at one end of the piston rod of the second hydraulic cylinder.

[0010] Preferably, the pushing structure includes a support plate, a pusher block, a discharge hole, and a hydraulic cylinder. The discharge hole is provided through the side of the resistance furnace away from the furnace door. A furnace door assembly is installed at the position of the discharge hole on the side of the resistance furnace away from the furnace door. The support plate is fixedly connected to the side of the resistance furnace away from the furnace door below the discharge hole. The top surface of the support plate is fixedly connected to the hydraulic cylinder. One side of the main body of the hydraulic cylinder is fixedly connected to the support plate. One end of the piston rod of the hydraulic cylinder is fixedly connected to the pusher block. The pusher block is inserted into and slidably connected to the discharge hole.

[0011] Compared with the prior art, this utility model provides a heating device for precise temperature control in aluminum alloy heat treatment, which has the following beneficial effects:

[0012] 1. This precise temperature-controlled aluminum alloy heat treatment heating equipment features a multi-parameter cooling structure with multiple cooling zones within the cooling chamber, encompassing various cooling methods such as water cooling, oil cooling, and air cooling. Through the ingenious coordination of the motor, lead screw, and slider, the cooling mode can be automatically and precisely switched according to the preset cooling process. This changes the traditional equipment's single or cumbersome cooling method, greatly improving the equipment's adaptability to different aluminum alloy materials and heat treatment processes.

[0013] 2. This precise temperature-controlled aluminum alloy heat treatment heating equipment features a pushing structure that automatically pushes the heated workpiece to the cooling box. After cooling, the clamping structure automatically clamps the workpiece, avoiding bumps and oxidation caused by manual operation. The heating, cooling, and material handling structures work closely together through a preset program to achieve precise coordination. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model;

[0015] Figure 2 This is an exploded view of the structure of this utility model;

[0016] Figure 3 This is a cross-sectional schematic diagram of the multi-parameter cooling structure of this utility model;

[0017] Figure 4 for Figure 3 A magnified view of part A in the diagram.

[0018] In the diagram: 1. Resistance furnace; 2. C-shaped bracket; 3. Bracket frame; 4. Motor; 5. Support plate; 6. Hydraulic cylinder one; 7. L-shaped bracket; 8. Hydraulic cylinder two; 9. Clamping assembly; 10. Cooling box; 11. Partition plate; 12. Mesh plate; 13. Sliding hole; 14. Lead screw; 15. Sliding block; 16. Push block; 17. Discharge hole; 18. Limiting block; 19. Fan. Detailed Implementation

[0019] 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.

[0020] Please see Figure 1-4A precise temperature-controlled aluminum alloy heat treatment heating device includes a resistance furnace 1. A multi-parameter cooling structure is provided on one side of the furnace door of the resistance furnace 1, and a clamping structure is provided above the multi-parameter cooling structure. A pushing structure is provided on the side of the resistance furnace 1 away from the furnace door.

[0021] Furthermore, the multi-parameter cooling structure includes a support frame 3, a motor 4, a lead screw 14, a slider 15, a sliding hole 13, and a limiting block 18. The support frame 3 is fixedly connected to one side of the furnace door of the resistance furnace 1. The open side of the support frame 3 is fixedly connected to the resistance furnace 1. The motor 4 is fixedly connected to one side of the support frame 3. The main body of the motor 4 is fixedly connected to the support frame 3. The output shaft of the motor 4 passes through the support frame 3 and is rotatably connected to it. One end of the output shaft of the motor 4 is fixedly connected to the lead screw 14 via a coupling. The other end of the lead screw 14 is rotatably connected to the inner wall of the support frame 3 away from the motor 4. The top surface of the support frame 3 has a through-hole opening. There is a sliding hole 13, the center line of the long side of the sliding hole 13 is parallel to the axis of the lead screw 14. A threaded hole is opened through one side of the slider 15, and the threaded hole of the slider 15 is threadedly connected to the lead screw 14. A limit block 18 is fixedly connected to the side of the slider 15 opposite to the sliding hole 13. The limit block 18 passes through the sliding hole 13 and is slidably connected to the sliding hole 13. The bracket frame 3 is a support for a multi-parameter cooling structure. The motor 4 makes the lead screw 14 rotate. The rotation of the lead screw 14 makes the slider 15 slide on the lead screw 14. The sliding hole 13 and the limit block 18 are used to prevent the slider 15 from rotating with the lead screw 14, but to slide on the lead screw 14.

[0022] Furthermore, the multi-parameter cooling structure also includes a cooling box 10 and partitions 11. The side of the limiting block 18 facing away from the slider 15 is fixedly connected to the cooling box 10. The side of the cooling box 10 facing away from the opening is fixedly connected to the limiting block 18. The opening side of the cooling box 10 is flush with the bottom surface of the furnace chamber of the resistance furnace 1. Multiple partitions 11 are fixedly connected inside the cooling box 10, dividing the interior of the cooling box 10 into multiple parts. The cooling box 10 is used to install the partitions 11. The limiting block 18 connects the slider 15 and the cooling box 10. The cooling box 10 moves horizontally on the support frame 3 along with the slider 15. The partitions 11 divide the interior of the cooling box 10 into multiple parts, each corresponding to a different cooling method. Water, oil, or other coolants are added. After the aluminum alloy is heated and kept warm in the resistance furnace 1, the cooling method corresponding to the moving cooling box 10 corresponds to the furnace door of the resistance furnace 1. The furnace door is opened, and the aluminum alloy is moved to the cooling box 10 for cooling.

[0023] Furthermore, a mesh plate 12 is fixedly connected to one of the parts separated by the partition 11 inside the cooling box 10. The mesh side of the mesh plate 12 is parallel to the opening side of the cooling box 10. A fan 19 is installed between the side of the mesh plate 12 away from the opening of the cooling box 10 and the cooling box 10. The mesh plate 12 is used to support the aluminum alloy. The aluminum alloy that needs to be air-cooled is placed on the mesh plate 12. When air cooling is required, the fan 19 is turned on.

[0024] Furthermore, the clamping structure includes a C-shaped bracket 2, an L-shaped bracket 7, a second hydraulic cylinder 8, and a clamping assembly 9. The top surface of the bracket frame 3 is fixedly connected to the C-shaped bracket 2. The two ends of the two symmetrical folded edges of the C-shaped bracket 2 are fixedly connected to the bracket frame 3. The side of the C-shaped bracket 2 facing away from the bracket frame 3 is fixedly connected to the L-shaped bracket 7. One end of one folded edge of the L-shaped bracket 7 is fixedly connected to the C-shaped bracket 2. The side of the L-shaped bracket 7 opposite to the bracket frame 3 is fixedly connected to the second hydraulic cylinder 8. The bottom surface of the main body of the second hydraulic cylinder 8 is connected to the C-shaped bracket 2. The hydraulic cylinder 28 is fixedly connected to the side of the main body where the piston rod is mounted, which is fixedly connected to the side of the C-shaped bracket 2 away from the bracket frame 3. The piston rod of the hydraulic cylinder 28 passes through the bracket frame 3 and the hydraulic cylinder 28 is slidably connected to the bracket frame 3. A clamping assembly 9 is installed at one end of the piston rod of the hydraulic cylinder 28. The C-shaped bracket 2 is used to install the bracket frame 3 and the hydraulic cylinder 28. The L-shaped bracket 7 is used to install the main body of the hydraulic cylinder 28. One end of the piston rod of the hydraulic cylinder 28 drives the clamping assembly 9 to move up and down to clamp the aluminum alloy in the cooling box 10 after cooling.

[0025] Furthermore, the pushing structure includes a support plate 5, a pusher block 16, a discharge hole 17, and a hydraulic cylinder 6. The discharge hole 17 is provided through the side of the resistance furnace 1 away from the furnace door. A furnace door assembly is installed at the position of the discharge hole 17 on the side of the resistance furnace 1 away from the furnace door. The support plate 5 is fixedly connected to the bottom of the discharge hole 17 on the side of the resistance furnace 1 away from the furnace door. The top surface of the support plate 5 is fixedly connected to the hydraulic cylinder 6. One side of the main body of the hydraulic cylinder 6 is fixedly connected to the support plate 5. The piston rod of the hydraulic cylinder 6 is fixedly connected to the pusher block 16. The pusher block 16 is inserted into the discharge hole 17 and slidably connected to the discharge hole 17. The support plate 5 is used to install the hydraulic cylinder 6. The pusher block 16 is used to push the aluminum alloy in the resistance furnace 1 into the cooling box 10. The furnace door assembly outside the discharge hole 17 is opened, and the pusher block 16 pushes the aluminum alloy into the cooling box 10 through the discharge hole 17.

[0026] Structural Description:

[0027] Resistance Furnace 1: It has a box-shaped shape and serves as the main space for heating aluminum alloys in heat treatment. With the help of a precise temperature control system, it maintains the temperature inside the furnace according to the preset process requirements to heat and keep the aluminum alloy workpieces warm.

[0028] C-shaped bracket 2: Shaped like the letter "C", it is mounted above the multi-parameter cooling structure and is used to install the bracket frame 3 in the multi-parameter cooling structure, while also providing installation support for the hydraulic cylinder 8 in the clamping structure.

[0029] Support frame 3: It is frame-shaped and fixed on one side of the furnace door of resistance furnace 1. It serves as the mounting support for the other components in the multi-parameter cooling structure and provides support for the entire multi-parameter cooling structure.

[0030] Motor 4: Rectangular in shape, fixed on one side of the bracket frame 3, drives the lead screw 14 to rotate through the output shaft, providing power for the translation of the cooling box 10;

[0031] Support plate 5: Plate-shaped structure, located below the discharge hole 17 on the side of the resistance furnace 1 away from the furnace door, used to install the hydraulic cylinder 6 in the pushing structure;

[0032] Hydraulic cylinder 6: Cylindrical structure, mounted on support plate 5, pushes push block 16 to push aluminum alloy workpiece in resistance furnace 1 to cooling box 10 through extension and retraction of piston rod;

[0033] L-shaped bracket 7: It is L-shaped and fixed on the side of C-shaped bracket 2 away from bracket frame 3 to assist in the installation of hydraulic cylinder 8 in the clamping structure;

[0034] Hydraulic cylinder 28: Cylindrical structure, fixed by C-shaped bracket 2 and L-shaped bracket 7, its piston rod drives the clamping assembly 9 to move up and down to clamp the aluminum alloy workpiece cooled in the cooling box 10;

[0035] Clamping assembly 9: Installed at the end of the piston rod of hydraulic cylinder 2 8, the specific shape is designed according to the actual clamping requirements, and is used to clamp aluminum alloy workpieces in cooling box 10;

[0036] Cooling box 10: Box-shaped structure, connected to slider 15 by limiting block 18, the interior is divided into multiple areas by partition 11, used to store different coolants or achieve air cooling, to cool the aluminum alloy workpiece pushed from the resistance furnace 1.

[0037] Partition 11: A plate-like structure, fixed at equal intervals inside the cooling box 10, dividing the interior of the cooling box 10 into multiple independent areas to achieve different cooling methods;

[0038] Mesh plate 12: Plate-shaped with mesh holes, fixed in one area of ​​the cooling box 10, used to support aluminum alloy workpieces that require air cooling;

[0039] Sliding hole 13: An elongated hole on the top surface of the support frame 3, parallel to the axis of the lead screw 14, and cooperates with the limiting block 18 to restrict the movement of the slider 15, so that the slider 15 can only slide along the direction of the lead screw 14;

[0040] Lead screw 14: slender cylindrical shape, rotatably connected to the support frame 3 at both ends, rotates under the drive of motor 4, and drives slider 15 to move along its axial direction through threaded engagement;

[0041] Slider 15: Block structure, one side has a threaded hole for threaded connection with lead screw 14, and the other side is connected to limit block 18, which can achieve linear sliding under the drive of lead screw 14;

[0042] Push block 16: Block structure, inserted into the discharge hole 17, under the push of hydraulic cylinder 6, pushes the aluminum alloy workpiece in the resistance furnace 1 through the discharge hole 17 to the cooling box 10;

[0043] Discharge hole 17: A hole opened on the side of the resistance furnace 1 away from the furnace door, which is the channel for aluminum alloy workpieces to enter the cooling box 10 from the resistance furnace 1.

[0044] Limiting block 18: a block structure, one end of which is connected to slider 15 and the other end is connected to cooling box 10, ensuring that cooling box 10 moves synchronously with slider 15;

[0045] Fan 19: Installed on the side of the inner mesh plate 12 of the cooling box 10 away from the opening of the cooling box 10. After starting, it accelerates the air flow and cools the aluminum alloy workpiece on the mesh plate 12.

[0046] Working principle: The aluminum alloy workpiece to be processed is placed in the resistance furnace 1. The resistance furnace, through a precise temperature control system, controls the furnace temperature within a set range according to the material of the aluminum alloy and the requirements of the heat treatment process, heating and holding the workpiece to complete the corresponding heat treatment heating process. After heating, according to the pre-set cooling process, the motor 4 is started. The motor 4 drives the lead screw 14 to rotate. The lead screw 14 is threadedly engaged with the slider 15. Due to the restriction of the sliding hole 13 and the limit block 18, the slider 15 slides linearly along the lead screw 14, causing the cooling box 10 to move horizontally. The interior of the cooling box 10 is divided into multiple areas by the partition 11, corresponding to different cooling methods such as water cooling, oil cooling, and air cooling. The cooling box 10 is moved so that the area requiring the cooling method is aligned with the furnace door of the resistance furnace 1. The discharge hole 17 at the end of the resistance furnace 1 opposite to the furnace door is opened. The furnace door assembly is activated, and hydraulic cylinder 6 is started. Hydraulic cylinder 6 pushes pusher block 16, which pushes the aluminum alloy workpiece in the resistance furnace 1 through the discharge hole 17 to the corresponding cooling area in the cooling box 10. For example, if air cooling is required, the workpiece is pushed to the area where the mesh plate 12 and fan 19 are installed. If liquid cooling is required, the workpiece is pushed to the area containing coolant such as water or oil. After the workpiece enters the cooling box 10, the corresponding cooling equipment is started. If air cooling is used, fan 19 is turned on to accelerate air flow and achieve rapid air cooling. If liquid cooling is used, the aluminum alloy workpiece is in direct contact with the coolant to complete the liquid cooling process. After cooling is completed, hydraulic cylinder 8 is started. The piston rod of hydraulic cylinder 8 drives clamping assembly 9 to move downward to clamp the aluminum alloy workpiece in the cooling box 10. Then the piston rod rises to remove the workpiece, completing the entire aluminum alloy heat treatment process.

[0047] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A precise temperature-controlled aluminum alloy heat treatment heating device, comprising a resistance furnace (1), characterized in that: The resistance furnace (1) has a multi-parameter cooling structure on one side of the furnace door, and a clamping structure above the multi-parameter cooling structure. The resistance furnace (1) has a pushing structure on the side away from the furnace door. The multi-parameter cooling structure includes a support frame (3), a motor (4), a lead screw (14), a slider (15), a sliding hole (13), and a limiting block (18). The support frame (3) is fixedly connected to one side of the furnace door of the resistance furnace (1). The opening side of the support frame (3) is fixedly connected to the resistance furnace (1). The motor (4) is fixedly connected to one side of the support frame (3). The main body of the motor (4) is fixedly connected to the support frame (3). The output shaft of the motor (4) passes through the support frame (3) and is connected to the support frame (3). 3) Rotary connection: One end of the output shaft of the motor (4) is fixedly connected to a lead screw (14) via a coupling. The other end of the lead screw (14) is rotatably connected to the inner wall of the support frame (3) away from the motor (4). A sliding hole (13) is provided through the top surface of the support frame (3). The center line of the long side of the sliding hole (13) is parallel to the axis of the lead screw (14). A threaded hole is provided through one side of the slider (15). The threaded hole of the slider (15) is threadedly connected to the lead screw (14). A limit block (18) is fixedly connected to the side of the slider (15) opposite to the sliding hole (13). The limit block (18) passes through the sliding hole (13) and is slidably connected to the sliding hole (13). The multi-parameter cooling structure also includes a cooling box (10) and partitions (11). The side of the limiting block (18) away from the slider (15) is fixedly connected to the cooling box (10). The side of the cooling box (10) away from the opening is fixedly connected to the limiting block (18). The opening side of the cooling box (10) is flush with the bottom surface of the furnace chamber of the resistance furnace (1). Multiple partitions (11) are fixedly connected inside the cooling box (10) and divide the interior of the cooling box (10) into multiple parts.

2. The aluminum alloy heat treatment heating equipment with precise temperature control according to claim 1, characterized in that: A mesh plate (12) is fixedly connected to one of the parts separated by a partition plate (11) inside the cooling box (10). The mesh side of the mesh plate (12) is parallel to the opening side of the cooling box (10). A fan (19) is installed between the side of the mesh plate (12) away from the opening of the cooling box (10) and the cooling box (10).

3. The precise temperature-controlled aluminum alloy heat treatment heating equipment according to claim 1, characterized in that: The clamping structure includes a C-shaped bracket (2), an L-shaped bracket (7), a second hydraulic cylinder (8), and a clamping assembly (9). The top surface of the support frame (3) is fixedly connected to the C-shaped bracket (2). The two ends of the two symmetrical folds of the C-shaped bracket (2) are fixedly connected to the support frame (3). The side of the C-shaped bracket (2) facing away from the support frame (3) is fixedly connected to the L-shaped bracket (7). One end of one fold of the L-shaped bracket (7) is fixedly connected to the C-shaped bracket (2). The side of the L-shaped bracket (7) opposite to the support frame (3) is fixedly connected to the second hydraulic cylinder (8). The bottom surface of the main body of the second hydraulic cylinder (8) is fixedly connected to the C-shaped bracket (2). The side of the main body of the second hydraulic cylinder (8) where the piston rod is installed is fixedly connected to the side of the C-shaped bracket (2) facing away from the support frame (3). The piston rod of the second hydraulic cylinder (8) passes through the support frame (3) and the second hydraulic cylinder (8) is slidably connected to the support frame (3). One end of the piston rod of the second hydraulic cylinder (8) is equipped with a clamping assembly (9).

4. The precise temperature-controlled aluminum alloy heat treatment heating equipment according to claim 1, characterized in that: The pushing structure includes a support plate (5), a pusher block (16), a discharge hole (17), and a hydraulic cylinder (6). The side of the resistance furnace (1) away from the furnace door has a discharge hole (17) through it. A furnace door assembly is installed on the side of the resistance furnace (1) away from the furnace door at the position of the discharge hole (17). The support plate (5) is fixedly connected to the side of the resistance furnace (1) away from the furnace door below the discharge hole (17). The top surface of the support plate (5) is fixedly connected to the hydraulic cylinder (6). One side of the main body of the hydraulic cylinder (6) is fixedly connected to the support plate (5). One end of the piston rod of the hydraulic cylinder (6) is fixedly connected to the pusher block (16). The pusher block (16) is inserted into the discharge hole (17) and the pusher block (16) is slidably connected to the discharge hole (17).

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