Starting-up preheating method of thin-plate cut-tobacco drier and cut-tobacco drier pipeline system

Abstract

The invention belongs to the technical field of thin-plate cut-tobacco dryers, and discloses a start-up preheating method of a thin-plate cut-tobacco dryer and a cut-tobacco dryer pipeline system. A pressure establishing mode of the starting preheating method for the thin-plate cut-tobacco drier comprises the following steps that a main hot air pipeline reaches 50% of a set value; when the steam pipeline of the first area and the steam pipeline of the second area are both larger than 0 bar, the first pneumatic diaphragm regulating valve is opened to 5% of the set value; the second pneumatic diaphragm regulating valve is opened to 5% of the set value; the temperature of the main hot air pipeline reaches 100% plus 5 DEG C of the set value, and when the condensate water pipelines of the two areas are both larger than or equal to 0 kg / h, the first pneumatic diaphragm regulating valve and the second pneumatic diaphragm regulating valve are opened to 10% of the set value; when the temperature of the condensate water pipelines of the two areas is larger than or equal to 50 DEG C, the first pneumatic diaphragm regulating valve and the second pneumatic diaphragm regulating valve are opened to 15% of the set value; and if the pressure value of the steam pipeline in the first area is greater than 0.5 bar and the pressure value of the steam pipeline in the second area is greater than 0.25 bar, entering a heating mode. Condensate water of the thin-plate cut-tobacco drier can be discharged smoothly.

Description

Technical Field

[0001] This invention relates to the field of thin plate wire drying machine technology, and in particular to a method for preheating a thin plate wire drying machine and a piping system for the wire drying machine. Background Technology

[0002] The thin-plate drying machine is one of the key pieces of equipment in the tobacco processing production line. Its main function is to dry the cut tobacco shreds to form tobacco shreds that meet the process requirements. The thin-plate drying machine is a drum-type drying machine that uses steam as a heat source. It employs a combined conduction-convection drying method to quickly dry and shape the tobacco shreds, increasing their curl and elasticity, improving their quality and filling value, and achieving the required moisture content for the dried tobacco shreds. Existing two-stage thin-plate drying machines have two independently controlled drying zones, designated Zone 1 and Zone 2. The working process of the existing two-stage thin-plate drying machine includes: basic state, preheating stage, operation preparation stage, start-up stage, restart stage, production stage, final production stage, and cooling stage.

[0003] The existing thin plate wire drying machine is in the preheating stage (pressure building and temperature rise stage) during startup. The steam regulating valve in the steam pipeline system is open, allowing steam to enter the pipes and thin plates. High-pressure steam needs to eliminate condensate in the pipes and thin plates before gradually building steam pressure in zones 1 and 2 of the thin plates, after which the plate temperature rises. Due to back pressure (i.e., a partial vacuum inside the thin plates) in the two-stage thin plate wire drying machine's condensate recovery system, condensate drainage is poor or cannot be discharged in a timely manner during startup. When condensate drainage in the thin plates and pipes is poor or cannot be discharged in a timely manner: First, water accumulates inside the thin plate wire drying machine, reducing heat exchange efficiency and causing unstable system temperature control; second, water hammer occurs during steam entry into the pipes and thin plates, causing impact damage to the thin plates; third, it corrodes the thin plates, producing scale and triggering water hammer, leading to cracking and leakage; fourth, the equipment preheating time is long during start-up production, resulting in large fluctuations in cylinder wall temperature and compromising product quality. Summary of the Invention

[0004] The purpose of this invention is to provide a preheating method for a thin plate wire drying machine and a piping system for the wire drying machine, which can eliminate the problem of poor or untimely drainage of condensate in the start-up mode of the thin plate wire drying machine.

[0005] To achieve this objective, the present invention adopts the following technical solution: A preheating method for a thin plate wire drying machine, including a pressure building-up mode, wherein the pressure building-up mode includes the following steps: S1. Open the main steam control valve and the third pneumatic diaphragm regulating valve to make the hot air temperature in the main hot air pipeline reach 50% of the hot air set value required for production, and set the opening time to 5 minutes. S2. Detect the pressure values ​​of the steam pipeline in the first zone and the steam pipeline in the second zone. When the pressure values ​​are both greater than 0 bar, first open the first pneumatic diaphragm regulating valve to 5% of the steam set value required for production in the first zone, and set the opening time to 5 minutes; then open the second pneumatic diaphragm regulating valve to 5% of the steam set value required for production in the second zone, and set the opening time to 5 minutes. S3. Adjust the third pneumatic diaphragm regulating valve to make the hot air temperature in the main hot air pipeline reach 100% plus 5 degrees Celsius of the hot air setting value required for production. Detect the flow rate of condensate in the first zone condensate pipeline and the second zone condensate pipeline. If the flow rate is ≥0 kg / h, open the first pneumatic diaphragm regulating valve and the second pneumatic diaphragm regulating valve to 10% of the steam setting value required for production in the first zone and 10% of the steam setting value required for production in the second zone, respectively, and set the opening time to 10 minutes. S4. Detect the condensate temperature in the first zone condensate pipe and the second zone condensate pipe. If the temperature is ≥50℃, open the first pneumatic diaphragm regulating valve and the second pneumatic diaphragm regulating valve to 15% of the steam set value required for production in the first zone and 15% of the steam set value required for production in the second zone, respectively, and set the opening time to 10 minutes. S5. Detect the pipe pressure values ​​of the first zone steam pipe and the second zone steam pipe. If the pipe pressure value of the first zone steam pipe is >0.5 bar and the pipe pressure value of the second zone steam pipe is >0.25 bar, then enter the heating mode.

[0006] As an optional method for the preheating of the thin plate wire drying machine, in step S1, the values ​​of the first temperature sensor and the second temperature sensor are compared. If they are the same, the opening of the third pneumatic diaphragm regulating valve is kept unchanged; otherwise, an alarm is triggered indicating that the preheating hot air temperature is abnormal.

[0007] As an optional method for the preheating of the thin plate wire drying machine, in step S2, if the pressure values ​​of the first zone steam pipeline and the second zone steam pipeline are both <0 bar, an alarm outputs that the pipeline pressure is abnormal, and the first manual control valve and the second manual control valve are in the closed state.

[0008] As an optional method for the preheating of the thin plate wire drying machine, in step S4, if the condensate temperature in both the first zone condensate pipe and the second zone condensate pipe is <50℃, then the first pneumatic diaphragm regulating valve and the second pneumatic diaphragm regulating valve are opened to 18% of the steam setting value required for production in the first zone and 18% of the steam setting value required for production in the second zone, respectively, until the temperature values ​​are ≥50℃.

[0009] As an optional method for the preheating of the thin plate wire drying machine, in step S5, if the pipeline pressure value of the first zone steam pipeline is not greater than 0.5 bar and the pipeline pressure value of the second zone steam pipeline is not greater than 0.25 bar, then the first pneumatic diaphragm regulating valve and the second pneumatic diaphragm regulating valve are opened to 20% of the steam setting value required for production in the first zone and 20% of the steam setting value required for production in the second zone, respectively.

[0010] As an optional method for preheating the thin plate wire drying machine, the heating mode includes the following steps: S6. Adjust the third pneumatic diaphragm regulating valve so that the hot air temperature in the main hot air pipeline reaches 100% of the hot air set value required for production; S7. Open the first pneumatic diaphragm regulating valve and the second pneumatic diaphragm regulating valve to 20% of the steam setpoint required for production in the first zone and 20% of the steam setpoint required for production in the second zone, respectively, for 15 minutes.

[0011] As an optional method for the preheating of the thin plate wire drying machine, in step S7, the pipe pressure values ​​of the first zone steam pipe and the second zone steam pipe are detected. If the pipe pressure value of the first zone steam pipe is >0.7 bar and the pipe pressure value of the second zone steam pipe is >0.7 bar, then the heating mode is completed.

[0012] As an optional method for the preheating of the thin plate wire drying machine, if the pipeline pressure value of the first zone steam pipeline is not greater than 0.7 bar and the pipeline pressure value of the second zone steam pipeline is not greater than 0.7 bar, then the first pneumatic diaphragm regulating valve and the second pneumatic diaphragm regulating valve are opened to 22% of the steam setting value required for the first zone production and 22% of the steam setting value required for the second zone production, respectively.

[0013] The wire drying machine piping system employs the preheating method described in any of the preceding claims to control the wire drying machine piping system, wherein the wire drying machine piping system includes: The hot air supply unit includes a main hot air duct and a secondary hot air duct connected to the main hot air duct. The secondary hot air duct is used to connect to the drying cylinder of the thin plate drying machine. A first temperature sensor is installed on the secondary hot air duct. A second temperature sensor is installed in the dehumidification pipe of the thin plate drying machine. A heat exchanger is installed in the main hot air duct. The steam supply unit includes a main steam pipeline, a first-zone steam pipeline, a second-zone steam pipeline, a first external pipeline, a second external pipeline, and a hot air steam pipeline. The hot air steam pipeline, the first-zone steam pipeline, and the second-zone steam pipeline are all connected to the main steam pipeline. One end of the hot air steam pipeline is connected to the heat exchange inlet of the heat exchanger. The first-zone steam pipeline is connected to the first-zone steam inlet of the rotary joint of the thin plate wire drying machine. The second-zone steam pipeline is connected to the second-zone steam inlet of the rotary joint of the thin plate wire drying machine. One end of the first external pipeline is connected to the first-zone steam pipeline, and the other end of the first external pipeline is equipped with a first pressure gauge and a first vacuum breaking valve connected in parallel. One end of the second external pipeline is connected to the second-zone steam pipeline, and the other end of the second external pipeline is equipped with a second pressure gauge and a second vacuum breaking valve connected in parallel. The condensate recovery unit includes a condensate tank, a first-zone condensate pipeline, a second-zone condensate pipeline, and a heat exchange condensate pipeline. The heat exchange condensate pipeline, the first-zone condensate pipeline, and the second-zone condensate pipeline are all connected to the condensate tank. One end of the heat exchange condensate pipeline is connected to the heat exchange outlet of the heat exchanger. The first-zone condensate pipeline is connected to the first-zone condensate outlet of the rotary joint of the thin-plate wire drying machine. The second-zone condensate pipeline is connected to the second-zone condensate outlet of the rotary joint of the thin-plate wire drying machine. A first-zone flow sensor and a third temperature sensor are installed on the first-zone condensate pipeline, and a second-zone flow sensor and a fourth temperature sensor are installed on the second-zone condensate pipeline.

[0014] As an optional solution for the piping system of the wire drying machine, a main steam control valve is installed on the main steam pipeline, a first pneumatic diaphragm regulating valve is installed on the first zone steam pipeline, a second pneumatic diaphragm regulating valve is installed on the second zone steam pipeline, a third pneumatic diaphragm regulating valve is installed on the hot air steam pipeline, a first manual control valve is installed on the first external connecting pipe, and a second manual control valve is installed on the second external connecting pipe.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The preheating method for a thin-plate wire drying machine provided by this invention includes the following steps in a pressure establishment mode: S1. Open the main steam control valve and the third pneumatic diaphragm regulating valve to make the hot air temperature in the main hot air pipeline reach 50% of the hot air set value required for production, with a set opening time of 5 minutes; S2. Detect the pressure values ​​of the first zone steam pipeline and the second zone steam pipeline. When the pressure values ​​are both greater than 0 bar, first open the first pneumatic diaphragm regulating valve to 5% of the steam set value required for production in the first zone, with a set opening time of 5 minutes; then open the second pneumatic diaphragm regulating valve to 5% of the steam set value required for production in the second zone, with a set opening time of 5 minutes; S3. Adjust the third pneumatic diaphragm regulating valve to make the hot air temperature in the main hot air pipeline reach 100% plus 5 degrees Celsius of the hot air set value required for production, and detect the pressure values ​​in the first zone condensate pipeline and the second zone condensate pipeline. S4. If the flow rate of condensate is ≥0 kg / h, open the first and second pneumatic diaphragm regulating valves to 10% of the steam setpoint required for production in the first and second zones respectively, with an opening time of 10 minutes; S5. Detect the condensate temperature in the condensate pipelines of the first and second zones. If the temperature is ≥50℃, open the first and second pneumatic diaphragm regulating valves to 15% of the steam setpoint required for production in the first and second zones respectively, with an opening time of 10 minutes; S6. Detect the pipeline pressure in the steam pipelines of the first and second zones. If the pipeline pressure in the steam pipeline of the first zone is >0.5 bar and the pipeline pressure in the steam pipeline of the second zone is >0.25 bar, then enter the heating mode. When the thin plate drying machine is in the preheating stage, it first enters the pressure building mode, opens the main steam control valve and the third pneumatic diaphragm regulating valve, and can use the hot air temperature of the main hot air pipeline to heat the drying cylinder of the thin plate drying machine. By increasing the temperature of the thin plate, the back pressure is eliminated, thus eliminating the problem of poor drainage or inability to drain condensate in a timely manner when the thin plate drying machine is in operation.

[0016] The piping system of the wire drying machine provided by this invention allows the thin plate wire drying machine to first use the auxiliary hot air pipeline of the hot air supply unit to heat the drying cylinder of the thin plate wire drying machine in the start-up mode, so that the back pressure inside the thin plate is eliminated and pressure is established. When steam is introduced into the thin plate wire drying machine by the first zone steam pipeline and the second zone steam pipeline, the condensate generated can be discharged smoothly. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the connection of the piping system of the wire drying machine in an embodiment of the present invention. Figure 2 This is a flowchart of the pressure establishment mode in the start-up preheating method of the thin plate wire drying machine in an embodiment of the present invention.

[0019] Figure label: 100. Thin sheet drying machine; 101. Rotary joint; 102. Drying cylinder; 103. Dehumidifying fan; 1031. Dehumidifying pipe; 1032. Second temperature sensor; 1. Steam supply unit; 2. Condensate recovery unit; 3. Hot air supply unit; 11. Main steam pipeline; 111. Main steam control valve; 12. First zone steam pipeline; 121. First pneumatic diaphragm regulating valve; 122. First pressure sensor; 13. Second zone steam pipeline; 131. Second pneumatic diaphragm regulating valve; 132. Second pressure sensor; 14. First external pipeline; 141. First pressure gauge; 142. First vacuum breaking valve; 143. First manual control valve; 15. Second external pipeline; 151. Second pressure gauge; 152. Second vacuum breaking valve; 153. Second manual control valve; 16. Hot air steam pipeline; 161. Third pneumatic diaphragm regulating valve; 17. Third external pipeline; 171. Third pressure gauge; 172. Third vacuum breaking valve; 21. Condensate tank; 22. First zone condensate piping; 221. First zone flow sensor; 222. Third temperature sensor; 23. Second zone condensate piping; 231. Second zone flow sensor; 232. Fourth temperature sensor; 24. Heat exchange condensate piping; 31. Main hot air duct; 311. Heat exchanger; 32. Secondary hot air duct; 321. First temperature sensor. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] To eliminate the problem of poor or untimely drainage of condensate during the start-up mode of a thin-plate wire drying machine, this embodiment provides a preheating method for starting up a thin-plate wire drying machine and a piping system for the machine. The following describes the method in conjunction with... Figures 1 to 2 The specific content of this embodiment will be described in detail.

[0025] The preheating method for the thin plate wire drying machine provided in this embodiment includes a pressure establishment mode, which includes the following steps: S1, opening the main steam control valve 111 and the third pneumatic diaphragm regulating valve 161, allowing steam to enter the heat exchanger 311 through the hot air steam pipeline 16 and exchange heat with the ambient air to form process hot air, so that the hot air temperature in the main hot air pipeline 31 reaches 50% of the hot air set value required for production, and setting the start-up time to 5 minutes; S2, detecting the pressure values ​​of the first zone steam pipeline 12 and the second zone steam pipeline 13, when the pressure values ​​are both greater than 0 bar, first adjusting the first pneumatic diaphragm regulating valve 161. Valve 121 is opened to 5% of the steam setpoint required for production in the first zone, with an opening time of 5 minutes; then the second pneumatic diaphragm regulating valve 131 is opened to 5% of the steam setpoint required for production in the second zone, with an opening time of 5 minutes; S3, the third pneumatic diaphragm regulating valve 161 is adjusted so that the hot air temperature in the main hot air pipeline 31 reaches 100% plus 5 degrees Celsius of the hot air setpoint required for production. A PLC controller is used to compare whether the temperature values ​​of the first temperature sensor 321 and the second temperature sensor 1032 are consistent. If they are consistent, the valve opening of the third pneumatic diaphragm regulating valve 161 remains unchanged. S4. Detect the flow rate of condensate in the first zone condensate pipe 22 and the second zone condensate pipe 23. If the flow rate is ≥0 kg / h, open the first pneumatic diaphragm regulating valve 121 and the second pneumatic diaphragm regulating valve 131 to 10% of the steam setpoint required for production in the first zone and 10% of the steam setpoint required for production in the second zone, respectively, and set the opening time to 10 min. S5. Detect the temperature of condensate in the first zone condensate pipe 22 and the second zone condensate pipe 23. If the temperature is ≥50℃, open the first pneumatic diaphragm regulating valve 121 and the second pneumatic diaphragm regulating valve 131 to 15% of the steam setpoint required for production in the first zone and 15% of the steam setpoint required for production in the second zone, respectively, and set the opening time to 10 min. S6. Detect the pipe pressure of the first zone steam pipe 12 and the second zone steam pipe 13. If the pipe pressure of the first zone steam pipe 12 is >0.5 bar and the pipe pressure of the second zone steam pipe 13 is >0.25 bar, then enter the heating mode. When the thin plate drying machine 100 is in the preheating stage during startup, it first enters the pressure building mode, opens the main steam control valve 111 and the third pneumatic diaphragm regulating valve 161, and can use the hot air temperature of the main hot air pipeline 31 to heat the drying cylinder 102 of the thin plate drying machine 100. By increasing the temperature of the thin plate, the back pressure is eliminated, thus eliminating the problem of poor drainage or inability to drain condensate in a timely manner during the startup mode of the thin plate drying machine 100.

[0026] Further, in step S1, the values ​​of the first temperature sensor 321 on the auxiliary hot air duct 32 and the second temperature sensor 1032 in the dehumidification duct 1031 are compared. If they are the same, the opening of the third pneumatic diaphragm regulating valve 161 is kept unchanged; otherwise, an alarm is triggered that "the preheating hot air temperature is abnormal".

[0027] Further, in step S2, if the pressure values ​​of both the first zone steam pipeline 12 and the second zone steam pipeline 13 are <0 bar, an alarm output will be issued stating "Pipe pressure abnormal, first manual control valve 143 and second manual control valve 153 are closed." On-site operators must manually open the first manual control valve 143 and the first vacuum breaking valve 142 and the second vacuum breaking valve 152 to establish a connection with the external atmospheric pressure, thus resolving the vacuum issue in the steam pipeline. Steam enters the thin plates of zones 1 and 2 through the first zone steam pipeline 12 and the second zone steam pipeline 13, allowing the condensate in the two steam pipelines (first zone steam pipeline 12 and second zone steam pipeline 13) and the thin plates of zones 1 and 2 to enter the condensate tank 21 through the first zone condensate pipeline 22 and the second zone condensate pipeline 23.

[0028] Further, in step S4, if the condensate temperature values ​​in the first zone condensate pipe 22 and the second zone condensate pipe 23 are both <50℃, then the first pneumatic diaphragm regulating valve 121 and the second pneumatic diaphragm regulating valve 131 are opened to 18% of the steam setting value required for the first zone production and 18% of the steam setting value required for the second zone production, respectively, until the temperature values ​​are both ≥50℃.

[0029] Further, in step S5, if the pipeline pressure value of the first zone steam pipeline 12 is not greater than 0.5 bar and the pipeline pressure value of the second zone steam pipeline 13 is not greater than 0.25 bar, then the first pneumatic diaphragm regulating valve 121 and the second pneumatic diaphragm regulating valve 131 are opened to 20% of the steam setting value required for the first zone production and 20% of the steam setting value required for the second zone production, respectively.

[0030] Furthermore, the heating mode includes the following steps: S6, adjusting the third pneumatic diaphragm regulating valve 161 to make the hot air temperature in the main hot air pipeline 31 reach 100% of the hot air setting value required for production; S7, opening the first pneumatic diaphragm regulating valve 121 and the second pneumatic diaphragm regulating valve 131 to 20% of the steam setting value required for production in the first zone and 20% of the steam setting value required for production in the second zone, respectively, for a duration of 15 minutes.

[0031] Further, in step S7, the pipe pressure values ​​of the first zone steam pipe 12 and the second zone steam pipe 13 are detected. If the pipe pressure value of the first zone steam pipe 12 is greater than 0.7 bar and the pipe pressure value of the second zone steam pipe 13 is greater than 0.7 bar, the heating mode is completed. If the pipe pressure value of the first zone steam pipe 12 is not greater than 0.7 bar and the pipe pressure value of the second zone steam pipe 13 is not greater than 0.7 bar, then the first pneumatic diaphragm regulating valve 121 and the second pneumatic diaphragm regulating valve 131 are opened to 22% of the steam setpoint required for production in the first zone and 22% of the steam setpoint required for production in the second zone, respectively. For example, in this embodiment, the opening degree of the first pneumatic diaphragm regulating valve 121, the second pneumatic diaphragm regulating valve 131 and the third pneumatic diaphragm regulating valve 161 can be controlled by a PID controller.

[0032] In this embodiment, during the start-up process of the two-stage thin plate wire drying machine 100, the start-up mode of the two-stage thin plate wire drying machine 100 is completed and it enters the production standby state after the pressure establishment and heating modes are completed. The pressure establishment mode takes 35 minutes and the heating mode takes 15 minutes, for a total of 50 minutes.

[0033] This embodiment also provides a wire drying machine pipeline system. The wire drying machine pipeline system adopts the above-mentioned thin plate wire drying machine start-up preheating method to control the wire drying machine pipeline system. The wire drying machine pipeline system includes a hot air supply unit 3, a steam supply unit 1, and a condensate recovery unit 2.

[0034] The hot air supply unit 3 includes a main hot air duct 31 and a secondary hot air duct 32 connected to the main hot air duct 31. The secondary hot air duct 32 is used to connect to the drying cylinder 102 of the thin plate drying machine 100. A first temperature sensor 321 is installed on the secondary hot air duct 32. A second temperature sensor 1032 is installed in the dehumidification pipe 1031 of the dehumidification fan 103 of the thin plate drying machine 100. A heat exchanger 311 is installed in the main hot air duct 31. Steam supply unit 1 includes a main steam pipeline 11, a first-zone steam pipeline 12, a second-zone steam pipeline 13, a first external pipeline 14, a second external pipeline 15, and a hot air steam pipeline 16. The hot air steam pipeline 16, the first-zone steam pipeline 12, and the second-zone steam pipeline 13 are all connected to the main steam pipeline 11. One end of the hot air steam pipeline 16 is connected to the heat exchange inlet of the heat exchanger 311. The first-zone steam pipeline 12 is connected to the first-zone steam inlet of the rotary joint 101 of the thin plate wire drying machine 100. The steam inlet is connected, and the second zone steam pipe 13 is connected to the second zone steam inlet of the rotary joint 101 of the thin plate drying machine 100. One end of the first external pipe 14 is connected to the first zone steam pipe 12, and the other end of the first external pipe 14 is equipped with a first pressure gauge 141 and a first vacuum breaking valve 142 connected in parallel. One end of the second external pipe 15 is connected to the second zone steam pipe 13, and the other end of the second external pipe 15 is equipped with a second pressure gauge 151 and a second vacuum breaking valve 152 connected in parallel. The condensate recovery unit 2 includes a condensate tank 21, a first-zone condensate pipeline 22, a second-zone condensate pipeline 23, and a heat exchange condensate pipeline 24. The heat exchange condensate pipeline 24, the first-zone condensate pipeline 22, and the second-zone condensate pipeline 23 are all connected to the condensate tank 21. One end of the heat exchange condensate pipeline 24 is connected to the heat exchange outlet of the heat exchanger 311. The first-zone condensate pipeline 22 is used to connect to the first-zone condensate outlet of the rotary joint 101 of the thin plate wire drying machine 100. The second-zone condensate pipeline 23 is used to connect to the second-zone condensate outlet of the rotary joint 101 of the thin plate wire drying machine 100. A first-zone flow sensor 221 and a third temperature sensor 222 are installed on the first-zone condensate pipeline 22. A second-zone flow sensor 231 and a fourth temperature sensor 232 are installed on the second-zone condensate pipeline 23.

[0035] Furthermore, a main steam control valve 111 is installed on the main steam pipeline 11, a first pneumatic diaphragm regulating valve 121 is installed on the first zone steam pipeline 12, a second pneumatic diaphragm regulating valve 131 is installed on the second zone steam pipeline 13, a third pneumatic diaphragm regulating valve 161 is installed on the hot air steam pipeline 16, a first manual control valve 143 is installed on the first external connecting pipe, and a second manual control valve 153 is installed on the second external connecting pipe. A first pressure sensor 122 is installed on the first zone steam pipeline 12, and a second pressure sensor 132 is installed on the second zone steam pipeline 13. When the first manual control valve 143 and the second manual control valve 153 are closed, the first pressure sensor 122 can be used to detect the steam pressure in the first zone steam pipeline 12, and the second pressure sensor 132 can be used to detect the steam pressure in the second zone steam pipeline 13. When the thin plate drying machine 100 enters normal production, the first manual control valve 143 is used to close the first external connecting pipe, and the second manual control valve 153 is used to close the second external connecting pipe.

[0036] Furthermore, the steam supply unit 1 also includes a third external pipe 17. One end of the third external pipe 17 is connected to the hot air steam pipeline 16, and the other end of the third external pipe 17 is equipped with a third pressure gauge 171 and a third vacuum breaking valve 172 connected in parallel. When the hot air steam pipeline 16 is first connected, the steam encounters the low-temperature hot air steam pipeline 16 and the heat exchanger 311, which easily creates back pressure in the pipeline, resulting in poor drainage of condensate from the heat exchange outlet of the heat exchanger 311. By adding the third vacuum breaking valve 172, the back pressure in the pipeline can be eliminated, which helps to drain the condensate from the heat exchange outlet of the heat exchanger 311.

[0037] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A preheating method for a thin plate wire drying machine, characterized in that, This includes a pressure build-up mode, which comprises the following steps: S1. Open the main steam control valve (111) and the third pneumatic diaphragm regulating valve (161) to make the hot air temperature in the main hot air pipeline (31) reach 50% of the hot air setting value required for production, and set the opening time to 5 minutes. S2. Detect the pressure values ​​of the first zone steam pipeline (12) and the second zone steam pipeline (13). When the pressure values ​​are both greater than 0 bar, first open the first pneumatic diaphragm regulating valve (121) to 5% of the steam setting value required for the first zone production, and set the opening time to 5 minutes; then open the second pneumatic diaphragm regulating valve (131) to 5% of the steam setting value required for the second zone production, and set the opening time to 5 minutes. S3. Adjust the third pneumatic diaphragm regulating valve (161) to make the hot air temperature in the main hot air pipeline (31) reach 100% plus 5 degrees Celsius of the hot air setting value required for production. Detect the flow rate of condensate in the first zone condensate pipeline (22) and the second zone condensate pipeline (23). If the flow rate is ≥0 kg / h, open the first pneumatic diaphragm regulating valve (121) and the second pneumatic diaphragm regulating valve (131) to 10% of the steam setting value required for production in the first zone and 10% of the steam setting value required for production in the second zone, respectively, and set the opening time to 10 min. S4. Detect the condensate temperature in the first zone condensate pipe (22) and the second zone condensate pipe (23). If the temperature is ≥50℃, open the first pneumatic diaphragm regulating valve (121) and the second pneumatic diaphragm regulating valve (131) to 15% of the steam setting value required for production in the first zone and 15% of the steam setting value required for production in the second zone, respectively, and set the opening time to 10min. S5. Detect the pipe pressure values ​​of the first zone steam pipe (12) and the second zone steam pipe (13). If the pipe pressure value of the first zone steam pipe (12) is >0.5 bar and the pipe pressure value of the second zone steam pipe (13) is >0.25 bar, then enter the heating mode.

2. The preheating method for a thin plate wire drying machine according to claim 1, characterized in that, In step S1, the values ​​of the first temperature sensor (321) and the second temperature sensor (1032) are compared. If they are the same, the opening of the third pneumatic diaphragm regulating valve (161) is kept unchanged. Otherwise, an alarm is triggered indicating that the preheating hot air temperature is abnormal.

3. The preheating method for a thin plate wire drying machine according to claim 1, characterized in that, In step S2, if the pressure values ​​of the first zone steam pipeline (12) and the second zone steam pipeline (13) are both <0 bar, an alarm will be triggered to output abnormal pipeline pressure, and the first manual control valve (143) and the second manual control valve (153) will be closed.

4. The preheating method for starting up a thin plate wire drying machine according to claim 1, characterized in that, In step S4, if the condensate temperature in the first zone condensate pipe (22) and the second zone condensate pipe (23) is less than 50°C, the first pneumatic diaphragm regulating valve (121) and the second pneumatic diaphragm regulating valve (131) are opened to 18% of the steam setting value required for production in the first zone and 18% of the steam setting value required for production in the second zone, respectively, until the temperature values ​​are both ≥50°C.

5. The preheating method for starting up a thin plate wire drying machine according to claim 1, characterized in that, In step S5, if the pipeline pressure value of the first zone steam pipeline (12) is not greater than 0.5 bar and the pipeline pressure value of the second zone steam pipeline (13) is not greater than 0.25 bar, then the first pneumatic diaphragm regulating valve (121) and the second pneumatic diaphragm regulating valve (131) are opened to 20% of the steam setting value required for the first zone production and 20% of the steam setting value required for the second zone production, respectively.

6. The preheating method for starting up a thin plate wire drying machine according to any one of claims 1-5, characterized in that, The heating mode includes the following steps: S6. Adjust the third pneumatic diaphragm regulating valve (161) to make the hot air temperature in the main hot air pipeline (31) reach 100% of the hot air set value required for production; S7. Open the first pneumatic diaphragm regulating valve (121) and the second pneumatic diaphragm regulating valve (131) to 20% of the steam setting value required for production in the first zone and 20% of the steam setting value required for production in the second zone, respectively, for 15 minutes.

7. The preheating method for a thin plate wire drying machine according to claim 6, characterized in that, In step S7, the pipe pressure values ​​of the first zone steam pipe (12) and the second zone steam pipe (13) are detected. If the pipe pressure value of the first zone steam pipe (12) is greater than 0.7 bar and the pipe pressure value of the second zone steam pipe (13) is greater than 0.7 bar, then the heating mode is completed.

8. The preheating method for starting up a thin plate wire drying machine according to claim 7, characterized in that, If the pressure value of the first zone steam pipeline (12) is not greater than 0.7 bar and the pressure value of the second zone steam pipeline (13) is not greater than 0.7 bar, then the first pneumatic diaphragm regulating valve (121) and the second pneumatic diaphragm regulating valve (131) are opened to 22% of the steam setting value required for the first zone production and 22% of the steam setting value required for the second zone production, respectively.

9. A piping system for a wire drying machine, characterized in that, The preheating method for the thin-plate wire drying machine as described in any one of claims 1-7 is used to control the wire drying machine piping system, wherein the wire drying machine piping system comprises: The hot air supply unit (3) includes a main hot air duct (31) and a secondary hot air duct (32) connected to the main hot air duct (31). The secondary hot air duct (32) is used to connect to the drying cylinder (102) of the thin plate drying machine (100). A first temperature sensor (321) is provided on the secondary hot air duct (32). A second temperature sensor (1032) is provided in the dehumidification pipe (1031) of the thin plate drying machine (100). A heat exchanger (311) is provided in the main hot air duct (31). The steam supply unit (1) includes a main steam pipeline (11), a first-zone steam pipeline (12), a second-zone steam pipeline (13), a first external pipeline (14), a second external pipeline (15), and a hot air steam pipeline (16). The hot air steam pipeline (16), the first-zone steam pipeline (12), and the second-zone steam pipeline (13) are all connected to the main steam pipeline (11). One end of the hot air steam pipeline (16) is connected to the heat exchange inlet of the heat exchanger (311). The first-zone steam pipeline (12) is connected to the first... A steam inlet is connected to the first zone, and the steam pipeline (13) of the second zone is connected to the steam inlet of the second zone of the rotary joint (101) of the thin plate wire drying machine (100). One end of the first external pipeline (14) is connected to the first zone steam pipeline (12), and the other end of the first external pipeline (14) is provided with a first pressure gauge (141) and a first vacuum breaking valve (142) in parallel. One end of the second external pipeline (15) is connected to the second zone steam pipeline (13), and the other end of the second external pipeline (15) is provided with a second pressure gauge (151) and a second vacuum breaking valve (152) in parallel. The condensate recovery unit (2) includes a condensate tank (21), a first-zone condensate pipeline (22), a second-zone condensate pipeline (23), and a heat exchange condensate pipeline (24). The heat exchange condensate pipeline (24), the first-zone condensate pipeline (22), and the second-zone condensate pipeline (23) are all connected to the condensate tank (21). One end of the heat exchange condensate pipeline (24) is connected to the heat exchange outlet of the heat exchanger (311). The first-zone condensate pipeline (22) is used for connecting... The first zone condensate outlet of the rotary joint (101) of the thin plate wire drying machine (100) is connected to the second zone condensate outlet of the rotary joint (101) of the thin plate wire drying machine (100). The first zone condensate outlet is equipped with a first zone flow sensor (221) and a third temperature sensor (222). The second zone condensate outlet is equipped with a second zone flow sensor (231) and a fourth temperature sensor (232).

10. The piping system for a wire drying machine according to claim 9, characterized in that, The main steam pipeline (11) is equipped with a main steam control valve (111), the first zone steam pipeline (12) is equipped with a first pneumatic diaphragm regulating valve (121), the second zone steam pipeline (13) is equipped with a second pneumatic diaphragm regulating valve (131), the hot air steam pipeline (16) is equipped with a third pneumatic diaphragm regulating valve (161), the first external pipe is equipped with a first manual control valve (143), and the second external pipe is equipped with a second manual control valve (153).

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