Vacuum pumping mechanism applied to NMP rectification device

Abstract

The utility model discloses a vacuum pumping mechanism for NMP rectifying device, the utility model relates to NMP rectification technical field. This vacuum pumping mechanism for NMP rectifying device includes support frame, the top of support frame is provided with vacuum pumping mechanism, is used for reducing rectifying device internal gas pressure, the vacuum pumping mechanism includes: buffer assembly, including fixed mounting on the top of support frame buffer jar, the bottom fixed mounting of buffer jar has unloading valve, the inside fixed mounting of buffer jar has baffle, gas first enters filter jar and neutralization solution contact, and harmful ingredients in neutralization solution and NMP steam react, and preliminary eliminate toxicity, gas needs to pass through the filter screen and internal adsorption filler of filter frame subsequently, and filter screen blocks impurity, and filler depth adsorbs residual harmful substance, and the annular aperture structure of guide plate forces gas to only enter the adapter pipe after filter frame processing, cannot bypass purification link, and then is discharged by vacuum pump safely, prevent harmful gas exhalation.

Description

Technical Field

[0001] This utility model relates to the field of NMP distillation technology, specifically to a vacuum mechanism applied to an NMP distillation apparatus. Background Technology

[0002] NMP distillation is a process technology based on the principle of distillation separation to purify, recover, or refine NMP and its mixtures. Its core objective is to remove impurities such as moisture, low-boiling-point organic matter, and high-boiling-point residues from NMP through a cycle of "heating and vaporization-condensation separation" to obtain high-purity NMP products. It is widely used in NMP recovery and purification scenarios in the electronics, chemical, and pharmaceutical industries.

[0003] The existing utility model patent with publication number CN216629702U discloses a caprolactam distillation vacuum device, including a distillation column, a cooler, and a dry vacuum pump. The cooler is located at the top of the distillation column, and the dry vacuum pump is connected to the distillation column and controls the vacuum level inside the column in real time. The dry vacuum pump can be any combination of two of the following: a Roots vacuum pump, a multi-stage claw pump, a single-stage claw pump, or a screw vacuum pump. This utility model uses a dry vacuum pump as the vacuum pumping device, which can replace the traditional steam jet pump vacuum pumping device, saving steam, reducing system steam condensate, saving investment and operating costs, and has good industrial application value.

[0004] The aforementioned vacuum pumping device cannot completely prevent vapor droplets from entering the vacuum pump during use. If droplets enter the commonly used oil-cooled vacuum pump, it will cause oil contamination, swelling of seals, and wear of the pump itself. This will result in a decrease in vacuum level and a slower pumping speed during vacuuming. In addition, NMP vapor is slightly toxic and cannot be directly discharged. The aforementioned vacuum pumping device may cause NMP vapor to leak from the pumping pipe during use. Utility Model Content

[0005] To address the shortcomings of existing technologies, this invention provides a vacuum pumping mechanism for NMP distillation apparatus, which solves the problems of liquid affecting the operation of the vacuum pump and gas leakage.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a vacuum mechanism applied to an NMP distillation unit includes a support frame, and a vacuum mechanism is disposed above the support frame to reduce the internal gas pressure of the distillation unit. The vacuum mechanism includes:

[0007] A buffer assembly includes a buffer tank fixedly installed above a support frame. A discharge valve is fixedly installed at the bottom of the buffer tank. A baffle is fixedly installed inside the buffer tank. A limit frame is fixedly installed inside the buffer tank. A movable frame is movably installed above the limit frame. A top cover is fixedly installed at the top of the buffer tank. A gear ring is fixedly installed at the top of the movable frame. A motor is fixedly installed above the top cover. A gear is fixedly installed on the outside of the motor's shaft. A rotary joint is fixedly installed above the movable frame. A guide pipe is fixedly installed above the rotary joint. A pressure relief valve is fixedly installed above the guide pipe.

[0008] A filter assembly, located in front of the buffer assembly, is used to treat the discharged gas.

[0009] Preferably, the filtration assembly includes a filter tank fixedly installed above the support frame, a drain valve fixedly installed at the bottom of the filter tank, a filter frame fitted on the top of the filter tank, a filter screen fixedly installed at the bottom of the filter frame, an air guide plate fixedly installed on the top of the filter tank, an adapter pipe fixedly installed above the air guide plate, and a vacuum pump connected to the front side of the adapter pipe.

[0010] Preferably, the baffle has an inverted conical structure, there are three baffles in total, and the diameter of the central hole of the baffle decreases radially upwards. The movable frame has a ring-shaped flat plate structure inside, and the movable frame is rotatably connected to the top cover and the limiting frame.

[0011] Preferably, the gear ring and the gear mesh with each other, the guide tube is rotatably connected to the movable frame through a rotary joint, and the bottom front end of the guide tube is located inside the conical structure at the bottom of the filter tank.

[0012] Preferably, the filter tank is provided with a water inlet pipe on its side for adding neutralizing solution to the filter tank, and the bottom of the filter frame is provided with a fan-shaped notch distributed in a ring. The filter screen is installed in a ring in the notch at the bottom of the filter frame with the center of the filter frame as the reference.

[0013] Preferably, the air guide plate has a ring-shaped perforation structure at its center, the inner wall of the notch structure at the center of the transfer pipe is in contact with the outer side of the guide pipe, and the air inlet of the vacuum pump is connected to the pipe structure at the front of the transfer pipe.

[0014] Beneficial effects

[0015] This invention provides a vacuum pumping mechanism for NMP distillation units. Compared with the prior art, it has the following advantages:

[0016] (1) In the vacuum mechanism of the NMP distillation unit, the buffer assembly uses a tangential inlet pipe in the buffer tank to create a swirling flow of gas. This, combined with three stages of baffles with decreasing apertures, first intercepts most of the droplets. Simultaneously, the motor drives the movable frame to rotate via gear and ring gear meshing. The annular plate of the movable frame rotates the airflow, using centrifugal force to throw the residual droplets to the tank wall. The collected liquid is discharged promptly through the discharge valve, completing the first stage of efficient liquid removal. Secondly, the guide pipe guides the gas after preliminary liquid removal to the bottom of the filter tank. The neutralization solution in the filter tank covers the bottom of the guide pipe, and the gas must pass through the neutralization solution to flow upward. During this process, trace amounts of residual droplets in the gas are captured by the neutralization solution, achieving the second stage of droplet interception. The dual liquid removal process, through the close cooperation of the baffles, movable frame, discharge valve, neutralization solution, and guide pipe, ensures that the gas entering the transfer pipe and vacuum pump is free of liquid components, completely avoiding internal oil contamination, seal swelling, and rotor wear in the vacuum pump, and ensuring stable vacuum and pumping speed.

[0017] (2) The vacuum mechanism applied to the NMP distillation unit first enters the filter tank and comes into contact with the neutralization solution. The neutralization solution reacts with the harmful components in the NMP vapor to initially eliminate toxicity. Then the gas needs to pass through the filter screen and internal adsorption packing of the filter frame. The filter screen blocks impurities, the packing deeply adsorbs residual harmful substances, and the annular opening structure of the gas guide plate forces the gas to enter the transfer pipe only after being processed by the filter frame. It cannot bypass the purification process and is then safely discharged by the vacuum pump to prevent harmful gas from leaking out. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0019] Figure 2 This is a schematic diagram of the installation structure of the movable frame of this utility model;

[0020] Figure 3 This is a schematic diagram of the filter frame installation structure of this utility model;

[0021] Figure 4 This is a schematic diagram of the connection structure between the flow guide pipe and the filter tank of this utility model;

[0022] In the diagram: 1. Support frame; 2. Vacuuming mechanism; 21. Buffer assembly; 211. Buffer tank; 212. Discharge valve; 213. Baffle; 214. Limiting frame; 215. Movable frame; 216. Top cover; 217. Gear ring; 218. Motor; 219. Gear; 2110. Rotary joint; 2111. Guide pipe; 2112. Pressure relief valve; 22. Filter assembly; 221. Filter tank; 222. Drain valve; 223. Filter frame; 224. Filter screen; 225. Air guide plate; 226. Adaptor pipe; 227. Vacuum pump. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] Please see Figure 1-4 This utility model provides a technical solution: a vacuum mechanism applied to an NMP distillation unit includes a support frame 1, and a vacuum mechanism 2 is arranged above the support frame 1 to reduce the internal gas pressure of the distillation unit. The vacuum mechanism 2 includes:

[0025] The buffer assembly 21 includes a buffer tank 211 fixedly mounted above the support frame 1. A discharge valve 212 is fixedly mounted at the bottom of the buffer tank 211. A baffle 213 is fixedly mounted inside the buffer tank 211. A limit frame 214 is fixedly mounted inside the buffer tank 211. A movable frame 215 is movably mounted above the limit frame 214. A top cover 216 is fixedly mounted at the top of the buffer tank 211. A gear ring 217 is fixedly mounted on the top of the movable frame 215. A motor 218 is fixedly mounted above the top cover 216. A gear 219 is fixedly mounted on the outer side of the motor 218's shaft. A rotary joint 2110 is fixedly mounted above the movable frame 215. A guide pipe 2111 is fixedly installed above the adapter 2110, and a pressure relief valve 2112 is fixedly installed above the guide pipe 2111. The baffle 213 has an inverted conical structure, and there are three baffles 213. The central hole of the baffle 213 decreases radially upward. The movable frame 215 has a ring-shaped flat plate structure inside. The movable frame 215 is rotatably connected to the top cover 216 and the limiting frame 214. The gear ring 217 and the gear 219 mesh with each other. The guide pipe 2111 is rotatably connected to the movable frame 215 through the rotary joint 2110. The bottom front end of the guide pipe 2111 is located inside the conical structure at the bottom of the filter tank 221.

[0026] Specifically, the surface of the buffer tank 211 is provided with a pipe structure tangential to the inner wall of the buffer tank 211 for air intake. After the gas enters the interior of the buffer tank 211, it will generate a swirling flow under the guidance of the inner wall of the buffer tank 211 and move upward under the influence of the air pressure difference, contacting the bottom surface of the three-stage baffle 213. Some liquid entrained in the gas can adhere to the surface of the baffle 213, collect into droplets and fall. The gas needs to pass through the movable frame 215 to enter the interior of the guide pipe 2111. The movable frame is driven by the motor 218, gear 219, and gear ring 217. When the frame 215 rotates, its internal vertical plate structure will come into contact with the airflow. The liquid in the airflow can rotate under the action of the frame 215 and be thrown to the inner wall of the buffer tank 211 under the influence of centrifugal force. The liquid will gather at the bottom of the buffer tank 211 and be discharged through the discharge valve 212 at the bottom. The pressure relief valve 2112 at the top of the guide pipe 2111 can be opened when the vacuum pump 227 is turned off to allow external air to enter, balance the air pressure difference, and prevent the neutralization solution from backflowing.

[0027] The filter assembly 22, located in front of the buffer assembly 21, is used to treat the discharged gas. The filter assembly 22 includes a filter tank 221 fixedly installed above the support frame 1. A drain valve 222 is fixedly installed at the bottom of the filter tank 221. A filter frame 223 is fitted and installed above the filter tank 221. A filter screen 224 is fixedly installed at the bottom of the filter frame 223. A gas guide plate 225 is fixedly installed at the top of the filter tank 221. An adapter pipe 226 is fixedly installed above the gas guide plate 225. A vacuum pump is connected to the front of the adapter pipe 226. 227. A water inlet pipe is provided on the side of the filter tank 221 for adding neutralizing solution to the filter tank 221. The bottom of the filter frame 223 is provided with a fan-shaped notch distributed in a ring. The filter screen 224 is installed in a ring in the notch at the bottom of the filter frame 223 with the center of the filter frame 223 as the reference. The center of the air guide plate 225 is provided with an opening structure distributed in a ring. The inner wall of the notch structure in the center of the transfer pipe 226 is in contact with the outer side of the guide pipe 2111. The air inlet of the vacuum pump 227 is connected to the front pipe structure of the transfer pipe 226.

[0028] Specifically, the bottom end of the vertical structure on the front side of the guide pipe 2111 is located inside the conical structure at the bottom of the filter tank 221. Neutralization solution is added to the interior of the filter tank 221 through the inlet on the side of the tank. The neutralization solution, constrained by the conical structure at the bottom of the filter tank 221, converges at the bottom end of the guide pipe 2111, with the liquid level higher than the bottom end of the vertical structure on the front side of the guide pipe 2111. After the gas enters the interior of the filter tank 221 through the guide pipe 2111, it needs to pass through the neutralization solution to rise into the upper space of the filter tank 221, thus neutralizing the gas. The filter frame 223 can be filled with packing material to adsorb and neutralize harmful substances in the gas. The outer contour of the top of the filter frame 223 is restricted by the air guide plate 225 and the filter canister 221. The gas can only move upward through the filter screen 224 at the bottom of the filter frame 223. After being adsorbed and neutralized by the packing material, it enters the transfer pipe 226 through the annular opening structure in the center of the air guide plate 225. Finally, it is discharged through the air outlet of the vacuum pump 227. The drain valve 222 at the bottom of the filter canister 221 is used to discharge the ineffective neutralization solution inside the filter canister 221.

[0029] Specifically, the motor 218 is a Siemens 1FL6044-1AF61-2AA1, the vacuum pump 227 is a KNFN816.3KT.18, the pressure relief valve 2112 is a Spirax Sarco SV607, and the drain valve 222 is a GEMU 554. In addition, all contents not described in detail in this specification are prior art known to those skilled in the art.

[0030] During operation, the gas to be treated enters the buffer tank 211 through a tangential pipe on its side. Guided by the tank wall, it forms a swirling flow and moves upward. It first contacts three inverted conical baffles 213 fixed inside the tank, with the baffles' central holes decreasing radially upwards, effectively blocking some of the liquid droplets entrained in the gas. The droplets converge on the surface of the baffles 213 and then drip off. The gas then continues upwards into the movable frame 215 area. The motor 218 fixed on the top cover 216 starts, and the gear 219 on the outer side of its rotating shaft engages with the gear on the top of the movable frame 215. The toothed rings 217 mesh with each other, driving the movable frame 215 to rotate stably under the support of the limiting frame 214. The annular plate structure inside the movable frame 215 rotates synchronously with it, causing the airflow to rotate and, under the action of centrifugal force, throw the residual droplets onto the inner wall of the buffer tank 211. The droplets slide down the tank wall to the bottom of the tank and are discharged through the discharge valve 212 at the bottom of the buffer tank 211. The gas after preliminary liquid removal passes through the movable frame 215 and enters the rotary joint 2110 at the top. It is then guided into the guide pipe 2111 through the rotary joint 2110 and then transported to the... Inside the filter tank 221 of the filter assembly 22, the bottom front end of the guide pipe 2111 is located within the conical structure at the bottom of the filter tank 221. A neutralizing solution is added to the tank through the water inlet pipe on the side of the filter tank 221. The neutralizing solution converges within the conical structure and submerges the bottom end of the guide pipe 2111. Gas must pass through the neutralizing solution to flow upwards. The gas then passes through the filter screen 224 at the bottom of the filter frame 223, which is fitted and installed above the filter tank 221. This filter screen 224 is installed in a ring around the center of the filter frame 223, within a fan-shaped notch at the bottom of the filter frame 223. Inside the filter 223, the gas is further processed by the adsorption packing inside the filter frame 223. The processed gas then enters the transfer pipe 226 through the gas guide plate 225 fixed at the top of the filter tank 221 and with an annular opening in the center. Finally, it is extracted by the vacuum pump 227 connected to the front of the transfer pipe 226. When the vacuum pump 227 is turned off, the pressure relief valve 2112 above the guide pipe 2111 is opened to balance the gas pressure inside and outside the device and prevent the neutralization solution from flowing back. The drain valve 222 at the bottom of the filter tank 221 is used to periodically drain the ineffective neutralization solution in the tank.

[0031] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0032] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A vacuum pumping mechanism for an NMP distillation apparatus, comprising a support frame (1), characterized in that: A vacuum pumping mechanism (2) is provided above the support frame (1) to reduce the gas pressure inside the distillation unit. The vacuum pumping mechanism (2) includes: The buffer assembly (21) includes a buffer tank (211) fixedly installed above the support frame (1). A discharge valve (212) is fixedly installed at the bottom of the buffer tank (211). A baffle (213) is fixedly installed inside the buffer tank (211). A limiting frame (214) is fixedly installed inside the buffer tank (211). A movable frame (215) is movably installed above the limiting frame (214). A top cover (216) is fixedly installed at the top of the buffer tank (211). A gear ring (217) is fixedly installed on the top of the movable frame (215), a motor (218) is fixedly installed on the top of the top cover (216), a gear (219) is fixedly installed on the outside of the rotating shaft of the motor (218), a rotary joint (2110) is fixedly installed on the top of the movable frame (215), a guide pipe (2111) is fixedly installed on the top of the rotary joint (2110), and a pressure relief valve (2112) is fixedly installed on the top of the guide pipe (2111). A filter assembly (22) is disposed in front of the buffer assembly (21) for processing the discharged gas.

2. The vacuum pumping mechanism for an NMP distillation unit according to claim 1, characterized in that: The filter assembly (22) includes a filter tank (221) fixedly installed above the support frame (1). A drain valve (222) is fixedly installed at the bottom of the filter tank (221). A filter frame (223) is fitted on the top of the filter tank (221). A filter screen (224) is fixedly installed at the bottom of the filter frame (223). An air guide plate (225) is fixedly installed on the top of the filter tank (221). An adapter pipe (226) is fixedly installed above the air guide plate (225). A vacuum pump (227) is connected to the front side of the adapter pipe (226).

3. The vacuum pumping mechanism applied to an NMP distillation unit according to claim 1, characterized in that: The baffle (213) has an inverted conical structure. There are three baffles (213), and the central hole of the baffle (213) decreases radially upward. The movable frame (215) has a flat plate structure arranged in a ring inside. The movable frame (215) is rotatably connected to the top cover (216) and the limiting frame (214).

4. The vacuum pumping mechanism for an NMP distillation unit according to claim 1, characterized in that: The gear ring (217) meshes with the gear (219), and the guide pipe (2111) is rotatably connected to the movable frame (215) through the rotary joint (2110). The bottom front end of the guide pipe (2111) is located inside the conical structure at the bottom of the filter tank (221).

5. The vacuum pumping mechanism for an NMP distillation unit according to claim 2, characterized in that: The filter tank (221) is provided with a water inlet pipe on its side for adding neutralizing solution to the filter tank (221). The bottom of the filter frame (223) is provided with a fan-shaped notch distributed in a ring. The filter screen (224) is installed in a ring in the notch at the bottom of the filter frame (223) with the center of the filter frame (223) as the reference.

6. The vacuum pumping mechanism for an NMP distillation unit according to claim 2, characterized in that: The air guide plate (225) has a ring-shaped perforation structure at its center. The inner wall of the notch structure at the center of the adapter pipe (226) is in contact with the outer side of the guide pipe (2111). The air inlet of the vacuum pump (227) is connected to the front pipe structure of the adapter pipe (226).

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