A visual automatic exhaust system for liquid phase vinyl chloride shielding pump

Abstract

This utility model discloses a visual automatic venting system for a liquid-phase vinyl chloride shielded pump. The system includes a vinyl chloride spherical tank, a shielded pump, a polymerization reactor, and a vinyl chloride recovery gas holder. An explosion-proof sight glass and a first automatic control valve are installed in the pipeline between the shielded pump and the recovery gas holder. It is also equipped with a visual liquid level acquisition device and a PC computer display and control terminal. The visual liquid level acquisition device consists of a 780nm infrared LED array, an infrared sensitive camera, a waterproof junction box, and a 24V switching power supply. It utilizes the difference in absorption spectra between vinyl chloride and water in the near-infrared band, and achieves visual differentiation of gas and liquid through infrared light illumination and the camera's pseudo-color function. This system achieves visualization, automation, and precise control of the venting process, overcoming the shortcomings of existing venting methods and improving the safety and stability of chemical PVC production.

Description

Technical Field

[0001] This utility model belongs to the field of chemical production equipment and process control, specifically relating to a visual automatic exhaust system for liquid phase vinyl chloride shielded pumps in PVC production. Background Technology

[0002] In the chemical PVC production process, liquid vinyl chloride is stored in a spherical tank and added to the polymerization reactor via a canned motor pump to participate in the reaction. Due to the limited structure of the canned motor pump, if the liquid vinyl chloride vaporizes and mixes with the liquid phase and enters the pump, it will severely damage the equipment and affect its performance. Since vinyl chloride vapor is flammable, explosive, and toxic, effectively removing the vapor phase from the liquid vinyl chloride in the pipeline is particularly important.

[0003] While existing technologies include remote visualization and automatic control methods, the viewing effect of remotely visualized images on a remote computer is poor due to the fact that liquid vinyl chloride is a colorless liquid. Furthermore, the images are often blurry and distorted due to interference from complex on-site environments, making it difficult to clearly see the gas conditions and identify gas characteristics. Whether automatic or manual identification is used, this process easily delays judgment time and affects the accuracy of control. Utility Model Content

[0004] The purpose of this invention is to provide a visual automatic venting system for liquid-phase vinyl chloride shielded pumps, in order to solve the problem that existing venting judgment methods are not conducive to identifying and affecting the accuracy of control and operational safety.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A visual automatic venting system for a liquid-phase vinyl chloride shielded pump includes a vinyl chloride spherical tank, a shielded pump, and a polymerization reactor connected in sequence by pipelines, a vinyl chloride recovery gas holder connected to the shielded pump by pipelines, a pipeline explosion-proof sight glass and a first automatic control valve arranged in sequence on the pipeline between the shielded pump and the vinyl chloride recovery gas holder, and the system also includes a visual liquid level acquisition device used in conjunction with the pipeline explosion-proof sight glass, and terminal equipment connected to the visual liquid level acquisition device and the first automatic control valve respectively.

[0006] Furthermore, the visual liquid level acquisition device includes a support frame fixed on the pipeline or ground where the explosion-proof sight glass is located, an infrared sensitive camera mounted on the support frame and corresponding to the explosion-proof sight glass, an infrared LED array mounted on both sides of the infrared sensitive camera, a waterproof junction box mounted on the support frame and connected to the infrared sensitive camera and the infrared LED array, and a switching power supply connected to the waterproof junction box; the infrared sensitive camera is connected to a terminal device, and the infrared sensitive camera is located directly in front of the explosion-proof sight glass.

[0007] Furthermore, the infrared LED array has a wavelength of 780±10nm, a power of 10W, and a light emission angle of 60°, and is located behind the infrared sensitive camera.

[0008] Furthermore, the switching power supply is selected as 24V.

[0009] Furthermore, a second self-control valve is provided on the pipeline between the vinyl chloride spherical tank and the shielded pump, as well as on the pipeline between the shielded pump and the polymerization reactor, and both second self-control valves are connected to the terminal equipment.

[0010] Furthermore, the terminal device is a PC computer display and control terminal.

[0011] Compared with the prior art, the beneficial effects of this utility model are: This liquid-phase vinyl chloride shielded pump visual automatic venting system achieves precise visualization based on the near-infrared absorption difference principle. The significant color changes allow for a more intuitive assessment of venting status, preventing equipment damage from incomplete venting and ensuring continuous production. The system operates in the infrared band, unaffected by visible light interference, and its components are adaptable to complex chemical environments, exhibiting high stability and reliability. Utilizing plug-and-play components and a simple operating procedure, it boasts a high degree of automation, reducing labor intensity. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model.

[0013] Among them, 1-vinyl chloride spherical tank; 2-shielded pump; 3-polymerization kettle; 4-gas holder; 5-pipeline explosion-proof sight glass; 6-first automatic control valve; 7-infrared LED array; 8-infrared sensitive camera; 9-waterproof junction box; 10-24V switching power supply; 11-PC computer display and control terminal; 12-second automatic control valve; 13-support frame. Detailed Implementation

[0014] The preferred embodiments of this utility model will be described below with reference to the accompanying drawings.

[0015] like Figure 1 As shown, a visual automatic venting system for a liquid-phase vinyl chloride shielded pump is disclosed. The system includes a vinyl chloride spherical tank 1, a shielded pump 2, and a polymerization reactor 3 connected sequentially by pipelines. A vinyl chloride recovery gas holder 4 is connected to the shielded pump 2 by a pipeline. An explosion-proof sight glass 5 and a first automatic control valve 6 are sequentially installed on the pipeline between the shielded pump 2 and the vinyl chloride recovery gas holder 4. A key improvement to this system is the installation of a visual liquid level acquisition device at the explosion-proof sight glass 5. Both the visual liquid level acquisition device and the first automatic control valve 6 are connected to terminal equipment.

[0016] Liquid vinyl chloride is stored in a spherical tank, which is connected to a shielded pump 2 via a pipeline. The shielded pump 2 is then connected to a polymerization reactor 3 via a pipeline, forming the transport path for the liquid vinyl chloride. At the same time, the shielded pump 2 is connected to a vinyl chloride recovery gas holder 4 via another pipeline. On this pipeline, an explosion-proof sight glass 5 and a first automatic control valve 6 are installed sequentially from the outlet of the shielded pump 2.

[0017] The visual liquid level acquisition device includes a 780nm infrared LED array 7, an infrared sensitive camera 8, a waterproof junction box 9, and a 24V switching power supply 10. The 780nm infrared LED array 7 has a wavelength of 780 ± 10nm, a power of 10W, a beam angle of 60°, and is powered by 24V DC. This array is fixed to the side and rear of the explosion-proof sight glass 5 of the pipeline. The installation position ensures that the emitted light obliquely illuminates the liquid phase area inside the sight glass, while avoiding direct illumination of the infrared sensitive camera 8.

[0018] The infrared-sensitive camera 8, with a resolution of 1080P and a spectral response range of 700-1100nm, features a customizable pseudo-color mapping function. It is fixed directly in front of the pipe explosion-proof sight glass 5, with the lens aligned with the center of the sight glass 5. By activating the camera's "pseudo-color mode" and setting the color mapping rule of "high transmittance → red, low transmittance → blue," the differences in infrared transmittance are converted into a color image that is easy to observe.

[0019] The waterproof junction box 9, made of 304 stainless steel, is compatible with 24V power supply and camera wiring. It is mounted on support frame 13, which is fixed to the pipeline where the explosion-proof sight glass 5 is located, or to the ground. It centrally manages and connects the power and signal cables of the 780nm infrared LED array 7 and the infrared-sensitive camera 8, protecting the wiring and adapting to the humid environment of the workshop.

[0020] The 24V switching power supply 10, with an output current of 5A and a power indicator light, was purchased from a power accessory store. It powers the 780nm infrared LED array 7 and the infrared sensitive camera 8 via a waterproof junction box 9, ensuring stable operation of the entire visual liquid level acquisition device.

[0021] The terminal equipment can be a PC computer display and control terminal 11, which is placed in the workshop control room. It is connected to the infrared sensitive camera 8 and each automatic control valve via a high-speed data transmission line (such as fiber optic or high-performance network cable). Second automatic control valves 12 are installed on the pipeline between the vinyl chloride spherical tank 1 and the shielded pump 2, and on the pipeline between the shielded pump 2 and the polymerization reactor 3. Both of these second automatic control valves 12 are connected to the PC computer display and control terminal 11 and receive its instructions to precisely regulate the flow rate of liquid vinyl chloride in the pipeline.

[0022] The working process of this system: Before feeding into the polymerization reactor 3, the system controls the opening of the second automatic control valve 12 between the vinyl chloride spherical tank 1 and the shielded pump 2. Liquid vinyl chloride flows from the spherical tank into the shielded pump 2 through the pipeline. The shielded pump 2 starts the exhaust operation. The system closes the second automatic control valve 12 on the pipeline between the shielded pump 2 and the polymerization reactor 3, opens the first automatic control valve 6, and discharges the gaseous vinyl chloride in the liquid phase pipeline into the vinyl chloride recovery gas tank 4. The 780nm infrared LED array 7 emits infrared light with a wavelength of 780 ± 10nm. Since vinyl chloride and water have different absorption spectra in the near-infrared band (780 - 900nm), the vapor of vinyl chloride absorbs 780nm infrared light weakly (transmittance ≥90%), while water absorbs 780nm infrared light strongly (transmittance ≤70%). After the infrared light obliquely shines into the liquid phase region in the sight glass, a difference in light transmission occurs. Other suitable wavelengths can also be used in this application. The infrared-sensitive camera 8 automatically switches to infrared mode to capture this difference in light transmission. Utilizing its pseudo-color function, it displays the "highly translucent vinyl chloride area" in red and the "weakly translucent water / air area" in blue, thus creating a clear color image. The camera converts this color image into an electrical signal, which is transmitted via a signal cable to the signal processing module inside the waterproof junction box 9 for preliminary processing. Subsequently, it is sent via a data transmission cable to the PC computer display and control terminal 11.

[0023] After receiving the image data, the PC display and control terminal 11 analyzes and processes the image. By analyzing the distribution and proportion of red and blue areas in the image, it determines whether the gas phase content has reached the preset exhaust threshold. When the gas phase content reaches the exhaust threshold, the PC display and control terminal 11 immediately sends a closing command to the first automatic control valve 6 and an opening command to the second automatic control valve 12 between the shielded pump 2 and the polymerization reactor 3, discharging liquid vinyl chloride into the polymerization reactor 3. Throughout the control process, operators can control the valve opening and closing based on the displayed images.

[0024] In summary, through the reasonable connection and coordinated operation of the above components, this system achieves visualization, automation and precise control of the exhaust process of the liquid-phase vinyl chloride shielded pump 2, effectively solving the problems existing in the current exhaust method and ensuring the safe and stable operation of chemical PVC production.

Claims

1. A visual automatic venting system for a liquid-phase vinyl chloride shielded pump, comprising a vinyl chloride spherical tank, a shielded pump, and a polymerization reactor connected sequentially by pipelines, a vinyl chloride recovery gas holder connected to the shielded pump by pipelines, and an explosion-proof sight glass and a first automatic control valve sequentially installed on the pipeline between the shielded pump and the vinyl chloride recovery gas holder, characterized in that, It also includes a visual liquid level acquisition device used in conjunction with the pipeline explosion-proof sight glass, and terminal equipment connected to the visual liquid level acquisition device and the first automatic control valve respectively.

2. The visual automatic exhaust system as described in claim 1, characterized in that, The visual liquid level acquisition device includes a support frame fixed on the pipeline or the ground where the explosion-proof sight glass is located, an infrared sensitive camera mounted on the support frame and corresponding to the explosion-proof sight glass, an infrared LED array mounted on both sides of the infrared sensitive camera, a waterproof junction box mounted on the support frame and connected to the infrared sensitive camera and the infrared LED array, and a switching power supply connected to the waterproof junction box; the infrared sensitive camera is connected to a terminal device and is located directly in front of the explosion-proof sight glass.

3. The visual automatic exhaust system as described in claim 2, characterized in that, The infrared LED array has a wavelength of 780±10nm, a power of 10W, and a light emission angle of 60°. The infrared LED array is located behind and to the side of the infrared sensitive camera.

4. The visual automatic exhaust system as described in claim 2, characterized in that, The switching power supply is 24V.

5. The visual automatic exhaust system as described in claim 1, characterized in that, A second self-control valve is installed on the pipeline between the vinyl chloride spherical tank and the shielded pump, as well as on the pipeline between the shielded pump and the polymerization reactor. Both second self-control valves are connected to the terminal equipment.

6. The visual automatic exhaust system as described in claim 1, characterized in that, The terminal device is a PC computer display and control terminal.

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