Pressure casting device for spheroidal graphite cast iron well lid

Abstract

The utility model discloses pressure casting device of nodular cast iron well lid relates to well lid casting technical field. The utility model discloses including lower mould body, the upper mould body is arranged on the lower mould body surface, and the upper mould body top intercommunication has the liquid level pipe, the lower mould body top is provided with prompt mechanism, and the prompt mechanism includes the guide pipe intercommunication in the upper mould body top. The utility model discloses through setting prompt mechanism, can real -time detection mould cavity in the liquid level height of molten iron, when the molten iron fills up the mould cavity, and the movable pipe floats and contacts with the positioning block, forms mechanical trigger signal to accurate judgment filling type complete state, avoids the casting defect caused by the filling type shortage or overflow, and the exhaust mechanism opens automatically in the molten iron stationary stage, and the residual gas in the mould cavity and molten iron is discharged, effectively reduces the casting internal blowhole, shrinkage and so on, improves the casting compactness and mechanical property. After exhausting, the mechanism resets the seal automatically, prevents the molten iron oxidation.

Description

Technical Field

[0001] This utility model belongs to the field of manhole cover casting technology, and in particular relates to a pressure casting device for ductile iron manhole covers. Background Technology

[0002] Ductile iron manhole covers, due to their high strength, high toughness, and excellent fatigue resistance, have become an indispensable key component in urban infrastructure. Pressure casting equipment utilizes low-pressure casting technology to cast ductile iron manhole covers. The basic principle of this technology is as follows: dry inert gas is introduced into a sealed, insulated melting furnace. Under the pressure of the gas, the molten iron in the furnace rises along the riser pipe and smoothly fills the upper metal mold cavity through the gating system. Solidification and crystallization are then completed under constant pressure, resulting in a casting with a dense structure and clear contours.

[0003] In existing pressure casting equipment for casting manhole covers, controlling the molten iron filling process is a core and challenging technical problem. The commonly used control strategy is the time-pressure curve control method. This involves determining the gas pressure over time—from the start of pressurization to the complete filling of the mold cavity—through numerous process experiments after the equipment and mold are finalized. During actual production, the control system applies gas pressure to the holding furnace according to this preset curve, ensuring the molten iron precisely fills the mold cavity. However, this process of repeated trials consumes significant time, manpower, and resources, reducing production flexibility and increasing production costs.

[0004] To address this issue, we offer a pressure casting device for ductile iron manhole covers. Utility Model Content

[0005] The purpose of this utility model is to provide a pressure casting device for ductile iron manhole covers. By combining the structure of the indicator mechanism and the venting mechanism, it solves the problem in the prior art that it is inconvenient to monitor whether the molten iron has filled the mold cavity during the use of pressure casting devices.

[0006] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution.

[0007] This utility model relates to a pressure casting device for ductile iron manhole covers, comprising a lower mold body, an upper mold body being disposed on the surface of the lower mold body, and a liquid riser pipe being connected to the top of the upper mold body; a prompting mechanism is disposed on the top of the lower mold body, the prompting mechanism comprising a guide pipe connected to the top of the upper mold body, a connecting rod disposed on the top of the guide pipe, a positioning plate fixedly connected to the surface of the connecting rod, a positioning block fixedly connected to the bottom of the positioning plate, and a movable tube sleeved on the surface of the connecting rod; an exhaust mechanism is disposed inside the movable tube, the exhaust mechanism comprising a limiting cylinder fixedly connected to the bottom of the movable tube, a sealing plug disposed at the bottom of the limiting cylinder, and a baffle disposed at the top of the limiting cylinder.

[0008] The present invention is further configured such that the prompting mechanism includes a limiting plate fixedly connected to the bottom of the connecting rod, and vent holes respectively opened on one side and the top of the movable tube.

[0009] The present invention is further configured such that the exhaust mechanism includes a movable rod fixedly connected to the top of the sealing plug, the top of the movable rod extending through to the top of the limiting cylinder.

[0010] The present invention is further configured such that the exhaust mechanism includes a spring fixedly connected to the top of the limiting cylinder, and an exhaust hole opened at the top of the limiting cylinder.

[0011] The present invention is further configured such that the exhaust mechanism includes a support plate fixedly connected to one side of the baffle, and an active groove formed on one side of the active pipe.

[0012] The present invention is further configured such that the exhaust mechanism includes a bracket fixedly connected to the top of the upper mold body, and a cylinder fixedly connected to the bottom of the bracket.

[0013] The present invention is further configured such that a hydraulic cylinder is fixedly connected to the bottom of the lower mold body, and a mounting bracket is fixedly connected to the bottom of the hydraulic cylinder.

[0014] The present invention has the following beneficial effects.

[0015] 1. This utility model, through the inclusion of a prompting mechanism, can detect the molten iron level in the mold cavity in real time. When the mold cavity is full, the movable tube floats and contacts the positioning block, generating a mechanical trigger signal. This accurately determines the completion status of the filling process, avoiding casting defects caused by insufficient filling or overflow. The venting mechanism automatically opens during the molten iron settling stage, expelling residual gas from the mold cavity and molten iron, effectively reducing defects such as porosity and shrinkage in the casting, and improving the density and mechanical properties of the casting. After venting is complete, the mechanism automatically resets and seals to prevent oxidation of the molten iron.

[0016] 2. This utility model integrates the prompting mechanism and the exhaust mechanism on the top of the mold, resulting in a compact structure, clear guidance for moving parts, and reliable operation. The opening and closing of the exhaust channel is controlled by a cylinder, achieving automated operation, reducing manual intervention, improving production efficiency and consistency, eliminating the need for complex pressure and time curve tests, shortening the process debugging cycle, enhancing production flexibility, and making it suitable for the production needs of small batches and multiple specifications of manhole covers.

[0017] Of course, any product implementing this utility model does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0019] Figure 1 A three-dimensional diagram of a pressure casting device for ductile iron manhole covers.

[0020] Figure 2 This is a cross-sectional view of the upper mold body in the pressure casting device for ductile iron manhole covers.

[0021] Figure 3 This is a cross-sectional view of the movable pipe in the pressure casting device for ductile iron manhole covers.

[0022] Figure 4 This is a cross-sectional view of the limiting cylinder in the pressure casting device for ductile iron manhole covers.

[0023] Figure 5 This is a diagram showing the upward movement of the movable pipe in the pressure casting device for ductile iron manhole covers.

[0024] In the attached diagram: 1. Lower mold body; 2. Upper mold body; 3. Lifting pipe; 4. Indicating mechanism; 41. Guide pipe; 42. Connecting rod; 43. Positioning plate; 44. Positioning block; 45. Movable pipe; 46. Limiting plate; 47. Vent hole; 5. Exhaust mechanism; 51. Limiting cylinder; 52. Sealing plug; 53. Baffle; 54. Movable rod; 55. Spring; 56. Exhaust hole; 57. Support plate; 58. Movable groove; 59. Bracket; 510. Cylinder; 6. Hydraulic cylinder. Detailed Implementation

[0025] The technical solutions of the present utility model will be described below with reference to the accompanying drawings. The described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0026] Example 1

[0027] Please see Figures 1-5This utility model is a pressure casting device for ductile iron manhole covers, including a lower mold body 1, an upper mold body 2 on the surface of the lower mold body 1, and a liquid riser pipe 3 connected to the top of the upper mold body 2; a prompting mechanism 4 is provided on the top of the lower mold body 1, the prompting mechanism 4 includes a guide pipe 41 connected to the top of the upper mold body 2, a connecting rod 42 provided on the top of the guide pipe 41, a positioning plate 43 fixedly connected to the surface of the connecting rod 42, a positioning block 44 fixedly connected to the bottom of the positioning plate 43, and a movable pipe 45 sleeved on the surface of the connecting rod 42; an exhaust mechanism 5 is provided inside the movable pipe 45, the exhaust mechanism 5 includes a limiting cylinder 51 fixedly connected to the bottom of the movable pipe 45, a sealing plug 52 provided at the bottom of the limiting cylinder 51, and a baffle 53 provided at the top of the limiting cylinder 51.

[0028] As a preferred embodiment of the above: a mold cavity is formed between the upper mold body 2 and the lower mold body 1, and the two are in close contact to ensure the sealing of the mold cavity. A connecting flange is fixedly connected to the surface of the riser pipe 3 away from the upper mold body 2. The movable pipe 45 is partially located inside the guide pipe 41, and its bottom end is flush with the bottom of the guide pipe 41, and its surface is in close contact with the guide pipe 41. The bottom end of the movable pipe 45 is located on the surface of the sealing plug 52, and it is in close contact with the sealing plug 52 to ensure the sealing of the bottom end of the movable pipe 45. The riser pipe 3 connects the heat-preserving smelting furnace and the mold, and transports molten iron from the furnace to the mold cavity under the action of gas pressure. The indicator mechanism 4 is used to monitor whether the molten iron in the mold cavity is full, and through mechanical connection... The system provides feedback on the filling status. The guide tube 41 guides the movable tube 45 to move up and down, ensuring its accurate movement trajectory. The connecting rod 42 connects the cylinder 510 and the limiting plate 46 to transmit power. The positioning plate 43 and the positioning block 44 limit the upper limit position of the movable tube 45, serving as the mechanical trigger point for the filling signal. The movable tube 45 floats as the molten iron level rises, and is a key component for detecting the filling status of the molten iron. The exhaust mechanism 5 exhausts the gas inside the molten iron when it is stationary. The limiting cylinder 51 accommodates and guides the movement of the sealing plug 52 and the movable rod 54. The sealing plug 52 seals the bottom of the movable tube 45 in the non-exhausting state to prevent molten iron from entering the exhaust system. The baffle 53 is linked with the movable rod 54 to control the opening of the exhaust channel.

[0029] Example 2

[0030] Please see Figures 1-5Based on embodiment 1, the prompting mechanism 4 further includes a limiting plate 46 fixedly connected to the bottom of the connecting rod 42, and vent holes 47 respectively opened on one side and the top of the movable tube 45. The exhaust mechanism 5 further includes a movable rod 54 fixedly connected to the top of the sealing plug 52, with the top of the movable rod 54 extending through to the top of the limiting cylinder 51. The exhaust mechanism 5 also includes a spring 55 fixedly connected to the top of the inner part of the limiting cylinder 51, and an exhaust hole 56 opened at the top of the limiting cylinder 51. The exhaust mechanism 5 further includes a support plate 57 fixedly connected to one side of the baffle 53, and a movable groove 58 opened on one side of the movable tube 45. The exhaust mechanism 5 also includes a bracket 59 fixedly connected to the top of the upper mold body 2, and a cylinder 510 fixedly connected to the bottom of the bracket 59. A hydraulic cylinder 6 is fixedly connected to the bottom of the lower mold body 1, and a mounting bracket is fixedly connected to the bottom of the hydraulic cylinder 6.

[0031] As a preferred embodiment of the above: the limiting plate 46 is located inside the movable tube 45, and the limiting plate 46 prevents the movable tube 45 from detaching from the connecting rod 42, ensuring structural stability. The vent hole 47 is used to discharge air from the mold cavity. The bottom of the spring 55 is fixedly connected to the sealing plug 52. The spring 55 is located on the surface of the movable rod 54. The support plate 57 is fixedly connected to the guide tube 41. The output end of the cylinder 510 is fixedly connected to the connecting rod 42. A limiting block is fixedly connected to one side of the positioning plate 43. The bracket 59 has a limiting groove adapted to the limiting block on the side near the positioning plate 43. The mounting bracket is fixedly connected to the upper mold body 2. The mounting bracket has a mounting hole at the top. The movable rod 54 transmits the movement, and the spring 55 provides the restoring force to ensure that the sealing plug 52 remains closed in the non-venting state. The vent hole 56 discharges the gas generated during the molten iron settling process, reducing the porosity inside the casting. The support plate 57 fixes the position of the baffle 53 and enhances the structural stability. The movable groove 58 provides the movement space for the movable tube 45, ensuring that it can move up and down flexibly. The bracket 59 and the cylinder 510 provide power to control the up and down movement of the connecting rod 42, realizing the opening and closing of the venting channel. The hydraulic cylinder 6 is installed at the bottom of the lower mold body 1 to control the opening and closing of the mold.

[0032] The working principle of this invention is as follows: First, the riser pipe 3 is connected to the holding furnace via a connecting flange. During the casting process, dry inert gas is introduced into the holding furnace. Under the pressure of the gas, molten iron enters the mold cavity formed by the upper mold body 2 and the lower mold body 1 through the riser pipe 3. As the molten iron level rises, the air in the mold cavity is discharged through the vent hole 47 on the side of the movable pipe 45. The buoyancy of the molten iron pushes the movable pipe 45 and its internal structure to float upwards. When the movable pipe 45 rises to contact the positioning block 44, it indicates that the mold cavity has been completely filled with molten iron.

[0033] At this point, cylinder 510 is activated, causing connecting rod 42 and limit plate 46 to move upward, which in turn pulls the movable tube 45 upward as a whole. During the upward movement of the movable tube 45, baffle 53 pushes movable rod 54 and sealing plug 52 downward, stretching spring 55 and opening the exhaust channel at the bottom of movable tube 45. Gas released during the settling process of molten iron is discharged through exhaust hole 56 and vent hole 47 at the top of movable tube 45. After the preset settling time is reached, cylinder 510 drives connecting rod 42 downward, spring 55 pushes sealing plug 52 to reset, resealing the bottom of movable tube 45. At this time, the bottom of movable tube 45 does not contact the molten iron, avoiding adhesion or damage. After the casting solidifies, it is fully reset, and the mold can be opened and the part removed, completing one casting cycle.

[0034] The foregoing description only illustrates certain exemplary embodiments of the present invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A pressure casting device for ductile iron manhole covers, comprising a lower mold body (1), characterized in that: The lower mold body (1) is provided with an upper mold body (2), and the top of the upper mold body (2) is connected to a liquid riser pipe (3). The lower mold body (1) is provided with a prompting mechanism (4) at the top. The prompting mechanism (4) includes a guide tube (41) connected to the top of the upper mold body (2), a connecting rod (42) provided at the top of the guide tube (41), a positioning plate (43) fixedly connected to the surface of the connecting rod (42), a positioning block (44) fixedly connected to the bottom of the positioning plate (43), and a movable tube (45) sleeved on the surface of the connecting rod (42). The movable tube (45) is provided with an exhaust mechanism (5), which includes a limiting cylinder (51) fixedly connected to the bottom of the movable tube (45), a sealing plug (52) provided at the bottom of the limiting cylinder (51), and a baffle (53) provided at the top of the limiting cylinder (51).

2. The pressure casting device for ductile iron manhole covers according to claim 1, characterized in that: The prompting mechanism (4) also includes a limiting plate (46) fixedly connected to the bottom of the connecting rod (42), and ventilation holes (47) respectively opened on one side and the top of the movable tube (45).

3. The pressure casting device for ductile iron manhole covers according to claim 1, characterized in that: The exhaust mechanism (5) also includes a movable rod (54) fixedly connected to the top of the sealing plug (52), the top of the movable rod (54) extending through to the top of the limiting cylinder (51).

4. The pressure casting device for ductile iron manhole covers according to claim 1, characterized in that: The exhaust mechanism (5) also includes a spring (55) fixedly connected to the top of the limiting cylinder (51) and an exhaust hole (56) opened at the top of the limiting cylinder (51).

5. The pressure casting device for ductile iron manhole covers according to claim 1, characterized in that: The exhaust mechanism (5) also includes a support plate (57) fixedly connected to one side of the baffle (53) and an active groove (58) opened on one side of the active pipe (45).

6. The pressure casting device for ductile iron manhole covers according to claim 1, characterized in that: The exhaust mechanism (5) also includes a bracket (59) fixedly connected to the top of the upper mold body (2) and a cylinder (510) fixedly connected to the bottom of the bracket (59).

7. The pressure casting device for ductile iron manhole covers according to claim 1, characterized in that: The bottom of the lower mold body (1) is fixedly connected to a hydraulic cylinder (6), and the bottom of the hydraulic cylinder (6) is fixedly connected to a mounting bracket.

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