A pulp molding temperature control energy-saving system and control method

Abstract

The application discloses a pulp molding temperature control energy-saving system and a control method, which comprises a steam inlet pipeline with a steam trap, a condensate recovery pipeline and a plurality of steam molds connected with the steam inlet pipeline and the condensate recovery pipeline. Any steam mold is connected with the condensate recovery pipeline through a steam trap mechanism to remove the condensate in the pipeline. Any steam mold is also connected with a temperature control mechanism. The temperature control mechanism is also connected with the steam trap mechanism corresponding to the steam mold through an analog quantity pneumatic valve. The opening degree of the analog quantity pneumatic valve is outputted in proportion to the temperature of the steam mold to control the temperature of the steam mold. The application can greatly reduce the energy consumption, and keep the constant temperature of the steam mold through the control of the temperature sensor and the analog quantity pneumatic bypass.

Description

Technical Field

[0001] This invention relates to the field of pulp molding technology, and in particular to a pulp molding temperature control and energy-saving system and control method. Background Technology

[0002] In the pulp molding industry, the standard production process typically involves vacuum suction molding followed by hot pressing for setting. Because the molding cycle time is low enough to supply heat for two hot pressing cycles, pulp molding equipment is usually configured with a single molding structure and a double setting structure. Setting often requires heating the mold to approximately 180 degrees Celsius. The industry commonly uses a heating plate, which can be electrically heated or heated with thermal oil. This heating method involves secondary heat reuse, resulting in high energy consumption. Furthermore, thermal oil heating carries the risk of leakage, and the maintenance costs of thermal oil boilers are substantial.

[0003] There is also a new type of heating method in the industry: the new steam mold can be heated directly with steam, with extremely high heat conversion efficiency. However, if the steam mold is kept circulating, the amount of steam used is huge, and the energy consumption is still huge. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of this invention is to propose a pulp molding temperature control and energy-saving system and control method to solve the problems mentioned in the background art.

[0005] The technical solution adopted by the present invention to solve its technical problem is: a pulp molding temperature control and energy-saving system, including a steam inlet pipe with a condensate drain valve, a condensate recovery pipe, and multiple steam molds connecting the steam inlet pipe and the condensate recovery pipe. Any one of the steam molds is connected to the condensate recovery pipe through a condensate draining mechanism to remove condensate from the pipe. Any one of the steam molds is also connected to a temperature control mechanism. The temperature control mechanism is also connected to the corresponding condensate draining mechanism of the steam mold through an analog pneumatic valve. The opening degree of the analog pneumatic valve is adjusted according to the temperature of the steam mold to output a proportional temperature to control the temperature of the steam mold.

[0006] As a further improvement of the present invention: a shut-off valve and a drain valve are provided at the front end of the steam inlet pipeline, the shut-off valve is located at the steam inlet end of the steam inlet pipeline, and the drain valve is located at the rear end of the shut-off valve.

[0007] As a further improvement of the present invention: the steam inlet pipe is also provided with multiple pull-down pipes, any one of the pull-down pipes is connected to a steam mold, and the pull-down pipe is also provided with a shut-off valve.

[0008] As a further improvement of the present invention: the steam mold includes an upper mold and a lower mold, the air inlet of the upper mold and the lower mold are connected to their corresponding pull-down pipes, and the air outlet of the upper mold and the lower mold are respectively connected to a drainage mechanism through pipes.

[0009] As a further improvement of the present invention: the drainage mechanism is provided with a first drainage valve, a second drainage valve, a first shut-off valve and a second shut-off valve, the first drainage valve, the second drainage valve, the first shut-off valve and the second shut-off valve are respectively connected to the condensate recovery pipeline, the first drainage valve and the first shut-off valve are connected to the shaping lower mold, and the second drainage valve and the second shut-off valve are connected to the shaping lower mold.

[0010] As a further improvement of the present invention: the temperature control mechanism includes a temperature sensor and a temperature controller, the temperature sensor is connected to the temperature controller, and the temperature sensor is disposed at the air outlet end of the shaping mold.

[0011] As a further improvement of the present invention: the temperature controller is connected to an analog pneumatic valve, the analog pneumatic valve is also connected to a first shut-off valve, and the temperature sensor detects the temperature at the outlet end of the forming mold, so that the temperature controller adjusts the opening degree of the analog pneumatic valve to output proportional temperature control of the outlet end temperature of the forming mold.

[0012] As a further improvement of the present invention: a connecting pipe is also provided at the end of the steam inlet pipe, one end of the connecting pipe is connected to the end of the steam inlet pipe, the other end of the connecting pipe is one end of the condensate recovery pipe, and a drain valve is provided on the connecting pipe.

[0013] As a further improvement of the present invention: the other end of the condensate recovery pipeline is connected to the condensate recovery system.

[0014] On the other hand, the present invention adopts the following technical solution: a pulp molding temperature control and energy-saving control method, which applies the above-mentioned pulp molding temperature control and energy-saving system, and further includes the following steps:

[0015] Controlled steam is delivered along the steam inlet pipe into multiple steam molds;

[0016] The temperature sensor detects the exit temperature t of the mold under shaping and compares it with the preset temperature value T;

[0017] If t > T, reduce the opening of the analog pneumatic valve to control the output of the proportional temperature Td of the temperature controller, so that the temperature at the outlet end of the mold remains constant.

[0018] If t < T, increase the opening of the analog pneumatic valve to control the output of the proportional temperature Tu of the temperature controller, so that the temperature at the outlet of the mold rises by the preset temperature value T.

[0019] Condensate recovery pipelines recover condensate.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] This invention constructs a steam system to systematically control the steam consumption of the steam mold. The steam system includes a steam inlet pipe and a condensate recovery pipe, and is equipped with a temperature control mechanism. It uses a steam trap and an analog pneumatic valve as a bypass to achieve efficient steam utilization and greatly reduce energy consumption. At the same time, the constant temperature of the steam mold is maintained by temperature sensors and analog pneumatic bypass control. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the system structure of the present invention.

[0023] Figure 2 This is a schematic diagram of the specific structure of the single steam mold of the present invention.

[0024] Figure 3 This is a schematic diagram of the specific structure of the dual steam mold of the present invention.

[0025] The diagram is labeled as follows: 1. Steam inlet pipe, 2. Condensate recovery pipe, 3. Steam mold, 31. Upper shaping mold, 32. Lower shaping mold, 4. Drainage mechanism, 41. First shut-off valve, 42. First drain valve, 43. Second shut-off valve, 44. Second drain valve, 5. Temperature control mechanism, 51. Temperature controller, 52. Temperature sensor, 53. Analog pneumatic ball valve, 6. Drain valve, 7. Shut-off valve, 8. Steam inlet, 9. Condensate recovery system. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0027] The present invention will now be further described in conjunction with the accompanying drawings and embodiments, such as... Figure 1The first embodiment of the present invention provides a pulp molding temperature control and energy-saving system, including a steam inlet pipe 1 with a condensate recovery pipe 2 and a plurality of steam molds 3 connecting the steam inlet pipe 1 and the condensate recovery pipe 2. Any one of the steam molds 3 is connected to the condensate recovery pipe 2 through a condensate draining mechanism 4 to remove condensate from the pipe. Any one of the steam molds 3 is also connected to a temperature control mechanism 5. The temperature control mechanism 5 is also connected to the condensate draining mechanism 4 corresponding to the steam mold 3 through an analog pneumatic ball valve 53. The opening degree of the analog pneumatic ball valve 53 is adjusted according to the temperature of the steam mold 3 to output a proportional temperature to control the temperature of the steam mold 3.

[0028] With this system structure, when the pulp molding equipment is working, the steam mold 3 is connected to the steam inlet pipe 1. Steam is transmitted along the steam inlet pipe 1 into multiple steam molds 3 to solidify the pulp in the steam mold 3. Since there is usually a long pipeline from the boiler to the steam inlet pipe 1, resulting in pipe loss and water vapor, a drain valve 6 needs to be installed at the front end to remove the condensate at the inlet and increase the inlet temperature. The steam mold 3 is connected to the steam inlet pipe 1. When the pulp is solidified in the steam mold 3, the steam condenses and produces condensate. This condensate is collected by the draining mechanism 4 and discharged into the condensate recovery pipe 2. The steam mold 3 is equipped with a temperature control mechanism 5 to detect the temperature of the steam mold 3 and control the opening degree of the analog pneumatic ball valve 53 to output a proportional temperature to keep the steam mold 3 at a constant temperature.

[0029] In an optional embodiment, a shut-off valve 7 and a steam trap 6 are provided at the front end of the steam inlet pipe 1. The shut-off valve 7 is located near the steam inlet of the steam inlet pipe 1, and the steam trap 6 is located at the rear end of the shut-off valve 7. Pulp molding steam typically requires an inlet steam temperature of 180 degrees Celsius. The steam enters through the steam inlet 8 pipe. A shut-off valve 7 is installed at the front end of the steam inlet 8 pipe to control the flow of the entire steam inlet pipe 1. A steam trap 6 is installed after the shut-off valve 7. Since there is usually a long pipe from the boiler to the steam inlet 8, resulting in pipe losses and moisture, a steam trap 6 is needed here to remove condensate from the steam inlet 8 and increase the inlet temperature.

[0030] In an optional embodiment, the steam inlet pipe 1 is further provided with multiple pull-down pipes, any one of which is connected to a steam mold 3, and the pull-down pipe is also provided with a shut-off valve 7.

[0031] In this embodiment, the steam inlet pipe 1 is installed on the equipment and on the steam mold 3. A pull-down pipe is led out from the steam inlet pipe 1, a shut-off valve 7 is installed, and then connected to the steam mold 3, so that steam is transmitted along the steam inlet pipe 1 into multiple steam molds 3.

[0032] In an optional embodiment, the steam mold 3 includes an upper mold 31 and a lower mold 32. The air inlet ends of the upper mold 31 and the lower mold 32 are connected to their corresponding pull-down pipes, and the air outlet ends of the upper mold 31 and the lower mold 32 are respectively connected to a drainage mechanism 4 through pipes.

[0033] In this embodiment, the single-unit pulp molding equipment includes two shaping and hot-pressing structures, which means it needs to be connected to the upper and lower molds of two sets of steam molds 3. One of the steam molds 3 includes an upper shaping mold 31 and a lower shaping mold 32. The upper shaping mold 31 and the lower shaping mold 32 share a steam inlet 8, so there will be no steam pipe blockage, saving cumbersome piping. However, the steam outlets of the upper shaping mold 31 and the lower shaping mold 32 must be separate. Otherwise, due to the difference in steam outlet temperature and pressure, the lower shaping mold 32 will not drain or vent smoothly, and the mold temperature will drop.

[0034] In an optional embodiment, the drainage mechanism 4 is provided with a first drainage valve 42, a second drainage valve 44, a first shut-off valve 41, and a second shut-off valve 43. The first drainage valve 42, the second drainage valve 44, the first shut-off valve 41, and the second shut-off valve 43 are respectively connected to the condensate recovery pipeline 2. The first drainage valve 42 and the first shut-off valve 41 are connected to the shaping lower mold 32, and the second drainage valve 44 and the second shut-off valve 43 are connected to the shaping lower mold 32.

[0035] In this embodiment, the first steam trap 42 and the first shut-off valve 41 recover the condensate formed by the condensation of steam in the lower mold 32, and the second steam trap 44 and the second shut-off valve 43 recover the condensate formed by the condensation of steam in the upper mold 31. Steam traps 6 are installed at the steam outlets of both the upper mold 31 and the lower mold 32, and bypass shut-off valves 7 are installed next to the steam traps 6. Both the steam traps 6 and the bypass shut-off valves 7 are installed below the steam mold 3 and above the condensate recovery pipeline 2 to facilitate the discharge of condensate and increase the intake temperature of the entire steam system.

[0036] In this embodiment, during the hot pressing and mold closing process of the pulp molding equipment, only the lower mold 32 is used for vacuuming to exchange heat. The steam pressure and temperature at the outlet of the lower mold 32 will decrease. However, the upper mold 31 does not undergo vacuuming; only heat exchange occurs on the surface of the wet pulp molded blank. Therefore, its outlet temperature and pressure will not decrease significantly. Since the steam mold 3 usually has a higher steam outlet pressure and temperature at the outlet of the upper mold 31 than at the outlet of the lower mold 32, if the steam outlets of the upper mold 31 and the lower mold 32 are connected together, the upper mold 31 will create air resistance to the lower mold 32, resulting in poor drainage and exhaust of the lower mold 32 and a decrease in the temperature of the steam mold 3.

[0037] In an optional embodiment, the temperature control mechanism 5 includes a temperature sensor 52 and a temperature controller 51. The temperature sensor 52 is connected to the temperature controller 51 and is disposed at the air outlet of the lower mold 32. The temperature sensor 52 detects the temperature at the air outlet of the lower mold 32, and the temperature controller 51 controls the output of a proportional temperature to keep the lower mold 32 at a constant temperature.

[0038] Furthermore, the temperature controller 51 is connected to an analog pneumatic ball valve 53, which is also connected to a first shut-off valve 41. The temperature sensor 52 detects the temperature at the outlet of the lower mold 32, so that the temperature controller 51 adjusts the opening of the analog pneumatic ball valve 53 to output a proportional temperature control to regulate the temperature at the outlet of the lower mold 32. Using the temperature sensor 52 installed on the lower mold 32, the temperature at the outlet of the lower mold 32 is collected in real time. Through PID control, when the temperature of the lower mold 32 decreases, the opening of the analog pneumatic ball valve 53 is increased; when it increases, the opening of the analog pneumatic ball valve 53 is decreased, thus maintaining a constant temperature for the mold.

[0039] In an optional embodiment, a connecting pipe is further provided at the end of the steam inlet pipe 1. One end of the connecting pipe is connected to the end of the steam inlet pipe 1, and the other end of the connecting pipe is one end of the condensate recovery pipe 2. A steam trap 6 is provided on the connecting pipe. A steam trap 6 is also installed at the end of the steam inlet pipe 1. This steam trap 6 is also used to remove moisture from the pipe and increase the intake temperature of the entire steam system.

[0040] In an optional embodiment, the other end of the condensate recovery pipe 2 is connected to the condensate recovery system 9. Installing the condensate recovery system 9 below the condensate recovery pipe 2 also facilitates condensate removal and reduces air resistance. The condensate recovery system 9 treats the recovered condensate to supplement boiler water for secondary use.

[0041] In this embodiment, the pulp molding steam typically requires an inlet steam temperature of 180 degrees Celsius. The steam enters through steam inlet 8 and is connected to a steam inlet 8 pipeline. A shut-off valve 7 is installed at the front end of the steam inlet 8 pipeline to control the flow of the entire steam inlet pipeline 1. A steam trap 6 is installed after the shut-off valve 7. Since the pipeline from the boiler to steam inlet 8 is usually quite long, resulting in pipe losses and moisture buildup, the steam trap 6 is installed here to remove condensate from the inlet and increase the inlet temperature. A steam trap 6 is also installed at the end of the steam inlet pipeline 1. This steam trap 6 is used to remove moisture from the pipeline and increase the overall steam system inlet temperature. This ensures that even if the steam system is shut down, any remaining steam in the pipeline is removed as moisture and does not remain in the pipeline. Steam inlet pipe 1 is installed on the equipment, above steam mold 3. A pipe is led down from steam inlet pipe 1, a shut-off valve 7 is installed, and then connected to steam mold 3. The single-unit pulp molding equipment includes two shaping and hot pressing structures, which means that two sets of shaping upper and lower molds need to be connected, including shaping upper mold 1, shaping lower mold 1, shaping upper mold 2, and shaping lower mold 2. The shaping upper and lower molds share a steam inlet 8, so there will be no steam pipe blockage, saving cumbersome piping. However, the steam outlets of the upper and lower molds must be separate. Otherwise, due to the difference in outlet temperature and pressure, the steam mold 3 will typically have a higher outlet pressure and temperature at the upper mold 31 than at the lower mold 32. This is because during the hot pressing and mold closing process in pulp molding equipment, only the lower mold is used for vacuuming and heat exchange, resulting in a decrease in outlet steam pressure and temperature. The upper mold 31, however, does not undergo vacuuming; only heat exchange occurs on the surface of the molded pulp preform, preventing a significant drop in its outlet temperature and pressure. If the steam outlets of the upper and lower molds are connected, the upper mold 31 will create air resistance on the lower mold 32, hindering drainage and venting, and causing a decrease in the temperature of the steam mold 3. Both the upper and lower mold steam outlets are equipped with steam traps 6, and bypass shut-off valves 7 are installed next to them. Both the steam traps 6 and bypass shut-off valves 7 should be installed below the steam mold 3 and above the condensate recovery pipe 2 to facilitate condensate drainage. The upper and lower mold outlets are bypassed. The upper mold 31 uses a shut-off valve 7, while the lower mold 32 uses an analog pneumatic ball valve 53, which can adjust the opening degree and cooperate with the system for temperature control.

[0042] Embodiment 2 of the present invention provides a method for temperature control and energy saving in pulp molding, which applies the above-described temperature control and energy saving system for pulp molding and further includes the following steps:

[0043] Controlled steam is conveyed along steam inlet pipe 1 into multiple steam molds 3;

[0044] Temperature sensor 52 detects the outlet temperature t of the shaping mold 32 and compares it with the preset temperature value T;

[0045] If t > T, reduce the opening of the analog pneumatic ball valve 53, control the output of the proportional temperature Td of the temperature controller 51, and keep the outlet temperature of the shaping mold 32 constant.

[0046] If t < T, increase the opening of the analog pneumatic ball valve 53, control the output of the proportional temperature Tu of the temperature controller 51, and make the outlet temperature of the shaping mold 32 rise by the preset temperature value T.

[0047] Condensate recovery pipe 2 recovers condensate. The preset temperature value T is set to 108 degrees Celsius.

[0048] This invention constructs a complete steam system and temperature control system specifically designed for pulp molding steam molds. The steam system includes a steam inlet pipe 1, a steam mold outlet pipe 3, and utilizes a steam trap 6 and an analog pneumatic ball valve 53 as bypasses to achieve efficient steam utilization, significantly reducing energy consumption. Ultimately, the steam consumption per segment of the pulp molding product is reduced to 0.4T. It also includes a downstream steam condensate recovery pipe. Simultaneously, the temperature sensor 52 and the analog pneumatic bypass control maintain a constant temperature for the steam mold 3. This effectively minimizes steam consumption in the steam mold 3, eliminating steam waste and reducing production energy consumption. Furthermore, the temperature control system ensures a constant temperature for the steam mold 3, meeting the process requirements for continuous production.

[0049] In summary, after reading this invention document, those skilled in the art can make various other corresponding modifications to the technical solutions and concepts based on this invention without creative mental effort, and all of these modifications fall within the scope of protection of this invention.

Claims

1. A temperature control and energy-saving system for pulp molding, characterized in that, The system includes a steam inlet pipe with a condensate drain valve, a condensate recovery pipe, and multiple steam molds connecting the steam inlet pipe and the condensate recovery pipe. Each steam mold is connected to the condensate recovery pipe via a condensate draining mechanism to remove condensate from the pipe. Each steam mold is also connected to a temperature control mechanism, which is connected to the corresponding condensate draining mechanism of the steam mold via an analog pneumatic valve. The temperature control mechanism controls the temperature of the steam mold by adjusting the opening degree of the analog pneumatic valve and outputting a proportional temperature according to the temperature of the steam mold. The steam inlet pipe is also provided with multiple pull-down pipes, each of which is connected to a steam mold. The pull-down pipe is also provided with a shut-off valve. The steam mold includes an upper shaping mold and a lower shaping mold. The air inlet ends of the upper shaping mold and the lower shaping mold are connected to their corresponding pull-down pipes. The air outlet ends of the upper shaping mold and the lower shaping mold are respectively connected to a drainage mechanism through pipes. The drainage mechanism is provided with a first drainage valve, a second drainage valve, a first shut-off valve, and a second shut-off valve. The first drainage valve, the second drainage valve, the first shut-off valve, and the second shut-off valve are respectively connected to the condensate recovery pipeline. The first drainage valve and the first shut-off valve are connected to the lower mold for shaping. The second drainage valve and the second shut-off valve are also connected to the lower mold for shaping. The temperature control mechanism includes a temperature sensor and a temperature controller. The temperature sensor is connected to the temperature controller and is located at the air outlet of the lower mold. The temperature controller is connected to an analog pneumatic valve, which is also connected to a first shut-off valve. The temperature sensor detects the temperature at the outlet end of the forming mold, so that the temperature controller adjusts the opening of the analog pneumatic valve to output a proportional temperature control to control the temperature at the outlet end of the forming mold.

2. The pulp molding temperature control and energy-saving system according to claim 1, characterized in that, The front end of the steam inlet pipeline is equipped with a shut-off valve and a drain valve. The shut-off valve is located at the steam inlet end of the steam inlet pipeline, and the drain valve is located at the rear end of the shut-off valve.

3. The pulp molding temperature control and energy-saving system according to claim 1, characterized in that, The steam inlet pipe is also provided with a connecting pipe at its end. One end of the connecting pipe is connected to the end of the steam inlet pipe, and the other end of the connecting pipe is one end of the condensate recovery pipe. A steam trap is provided on the connecting pipe.

4. The pulp molding temperature control and energy-saving system according to claim 1, characterized in that, The other end of the condensate recovery pipeline is connected to the condensate recovery system.

5. A method for temperature control and energy saving in pulp molding, using the temperature control and energy saving system for pulp molding as described in any one of claims 1-4, further comprising the following steps: Controlled steam is delivered along the steam inlet pipe into multiple steam molds; The temperature sensor detects the exit temperature t of the mold under shaping and compares it with the preset temperature value T; If t > T, reduce the opening of the analog pneumatic valve to control the output of the proportional temperature Td of the temperature controller, so that the temperature at the outlet end of the mold remains constant. If t < T, increase the opening of the analog pneumatic valve to control the output of the proportional temperature Tu of the temperature controller, so that the temperature at the outlet of the mold rises by the preset temperature value T. Condensate recovery pipelines recover condensate.

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