Distillation kettle for extracting strong and weak formaldehyde by using steam backwater

Abstract

The utility model relates to the technical field of distillation kettles, in particular to a distillation kettle for extracting strong and weak formaldehyde by utilizing steam backwater, which comprises a distillation kettle body, a support shell, a support opening, a lifting shell, a support pipe, a first support block, a second support block, a cleaning roller, a scraper, a rotating mechanism and a reciprocating lifting mechanism, the supporting opening is formed between the supporting shell and the distillation still body, the lifting shell is arranged in the supporting shell in a sliding mode, the supporting pipe is rotationally arranged on the inner top wall of the lifting shell, the supporting pipe penetrates through the side wall of the lifting shell and the supporting opening and extends into the distillation still body, and the end, away from the lifting shell, of the supporting pipe is sealed; two first supporting blocks are fixedly arranged on the side wall of the supporting pipe, a second supporting block is fixedly arranged on the side wall of the side, far away from the supporting shell, of the supporting pipe, and through the technical scheme, the problem that the cleaning efficiency is low after the distillation still body is used in the prior art is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of distillation kettles, in particular to a distillation kettle which utilizes steam return water to extract concentrated and diluted formaldehyde. Background Art

[0002] High-pressure distillation (also known as vacuum distillation) is an important method for separating and purifying compounds. It is particularly suitable for the separation and purification of high-boiling point substances and those compounds that have been thermally decomposed, oxidized or polymerized before reaching the boiling point during atmospheric distillation.

[0003] In the formaldehyde aqueous solution, formaldehyde exists in the form of formaldehyde hydrate or formaldehyde polymer hydrate, with a low free formaldehyde content. In the gas-liquid phase equilibrium relationship, formaldehyde and water are azeotropic. This composition increases with the increase of free formaldehyde content in water, that is, with the increase of temperature and pressure. According to this principle, using low-concentration formaldehyde as raw material, dilute formaldehyde can be evaporated under vacuum conditions, leaving a concentrated formaldehyde solution.

[0004] The current process of vacuum distillation in industry is to place the compounds to be separated and purified into a closed container, and heat and depressurize the container to achieve its production purpose.

[0005] In order to ensure the effect of the next use, the existing distillation kettle is cleaned by staff after use. In the prior art, when cleaning the inside of the distillation kettle, solvent oil is usually introduced into the inside of the distillation kettle, and then the operator flushes the inside of the distillation kettle. However, the volume of some distillation kettles is too large, so the flushing process is very inconvenient. It is difficult to clean completely by flushing with solvent oil alone, and it is also impossible to clean thoroughly, which affects the cleaning efficiency. Utility Model Content

[0006] The utility model provides a distillation kettle which utilizes steam return water to extract concentrated and diluted formaldehyde, thereby solving the problem of low cleaning efficiency of the distillation kettle body after use in the related art.

[0007] The technical scheme of the utility model is as follows: a distillation kettle for extracting concentrated and diluted formaldehyde by steam return water, comprising a distillation kettle body, a supporting shell, a supporting port, a lifting shell, a supporting pipe, a first supporting block, a second supporting block, a cleaning roller, a scraper, a rotating mechanism and a reciprocating lifting mechanism;

[0008] The support shell is fixedly arranged on the distillation kettle body;

[0009] The support opening is provided between the support shell and the distillation kettle body;

[0010] The lifting housing is slidably arranged in the supporting housing;

[0011] The support tube is rotatably arranged on the inner top wall of the lifting shell, the support tube penetrates the side wall of the lifting shell and the support port and extends into the distillation kettle body, and the support tube is sealed at one end away from the lifting shell;

[0012] Two first support blocks are fixedly arranged on the side wall of the support tube;

[0013] The second support block is fixedly arranged on a side wall of the support tube away from the support shell;

[0014] The cleaning roller is rotatably disposed between one of the first supporting blocks and the second supporting block, and cleaning bristles are evenly distributed on the cleaning roller, and the cleaning bristles are in contact with the inner wall of the distillation kettle body;

[0015] The scraper is fixedly arranged between the other first supporting block and the second supporting block, and the scraper is in contact with the inner wall of the distillation kettle body;

[0016] The rotating mechanism is arranged in the supporting shell and is used to control the supporting tube to rotate;

[0017] The reciprocating lifting mechanism is arranged in the supporting shell, and is used for controlling the lifting shell and the supporting tube to perform reciprocating lifting.

[0018] Preferably, the rotating mechanism comprises:

[0019] A driving port, the driving port being provided on the lifting shell;

[0020] a first gear, the first gear being arranged in the lifting housing for rotation corresponding to the driving port;

[0021] A first annular rack, wherein the first annular rack is fixedly disposed on the support tube;

[0022] wherein the first gear is meshed with the first annular rack;

[0023] A driving rod, the driving rod is rotatably disposed in the supporting shell, and the driving rod passes through the driving port and the first gear;

[0024] Wherein, the driving rod is slidably connected to the first gear;

[0025] A first motor, wherein the first motor is fixedly disposed on the supporting shell, and an output end of the first motor is fixedly connected to the driving rod.

[0026] Furthermore, an auxiliary cleaning mechanism is included, which is arranged in the support tube and is used to assist in cleaning the inner wall of the distillation kettle body. The auxiliary cleaning mechanism includes:

[0027] A first cavity, wherein the first cavity is opened in the first supporting block close to one side of the cleaning roller;

[0028] A first bevel gear, wherein the first bevel gear is fixedly arranged on the inner bottom wall of the first cavity, and a connecting column is fixedly arranged between the first bevel gear and the cleaning roller;

[0029] A connecting pipe, the connecting pipe being rotatably disposed between the supporting pipe and the first cavity, a second bevel gear being fixedly disposed on one end of the side wall of the connecting pipe close to the first cavity, and a third bevel gear being fixedly disposed on one end of the side wall of the connecting pipe away from the first cavity;

[0030] Wherein, the second bevel gear is meshed with the first bevel gear;

[0031] A fixed column, wherein the fixed column is fixedly arranged on the inner top wall of the lifting shell, and a fourth bevel gear is fixedly arranged on the fixed column, and the fourth bevel gear is meshed with the third bevel gear;

[0032] A flushing mechanism is arranged on the lifting shell and is used for flushing the inner wall of the distillation kettle body.

[0033] Furthermore, the flushing mechanism includes:

[0034] Flushing ports, the flushing ports being evenly distributed on the cleaning roller;

[0035] A connecting port, the connecting port is provided on the fixing column, and two ends of the connecting port are respectively connected with the flushing port and the first cavity;

[0036] A water inlet pipe is provided on the support shell through which the water inlet pipe penetrates and extends into the support pipe.

[0037] Furthermore, the reciprocating lifting mechanism includes:

[0038] A fixing opening, wherein a plurality of the fixing openings are provided on the lifting shell, and a lead screw nut is fixedly arranged in each of the fixing openings;

[0039] A reciprocating screw, wherein the reciprocating screw is provided in a plurality, the plurality of reciprocating screws are rotatably arranged in the support housing, and the reciprocating screw passes through the screw nut;

[0040] A synchronous rotation mechanism is arranged in the support shell and is used to control the reciprocating screw to rotate synchronously.

[0041] On the basis of the above scheme, the synchronous rotation mechanism comprises:

[0042] A second cavity, wherein the second cavity is formed on an inner top wall of the supporting shell;

[0043] A second gear, wherein a plurality of second gears are rotatably disposed in the second cavity, and the second gears are fixedly connected to the reciprocating screw;

[0044] a third gear, the third gear being rotatably disposed in the second cavity and meshing with the second gear;

[0045] A fourth gear is rotatably disposed in the second cavity, the fourth gear is meshed with the third gear, and the fourth gear is fixedly connected to the driving rod.

[0046] The working principle and beneficial effects of the utility model are:

[0047] 1. In the utility model, through the setting of the rotating mechanism, the operation of the first motor can drive the first gear to rotate, and at the same time, the meshing of the first gear and the first annular rack drives the support tube to rotate, and at the same time, the first support block and the second support block drive the cleaning roller and the scraper to clean the inner wall of the distillation kettle body;

[0048] 2. In the utility model, through the setting of the auxiliary cleaning mechanism, the rotation of the support tube can drive the third bevel gear to move around the fourth bevel gear, and at the same time, the meshing of the third bevel gear and the fourth bevel gear drives the connecting tube and the second bevel gear to rotate, and at the same time, the meshing of the first bevel gear and the second bevel gear drives the first bevel gear and the cleaning roller to rotate, thereby further improving the cleaning effect of the cleaning brush on the inner wall of the distillation kettle body. During the cleaning process, solvent oil can be introduced into the support tube through the water inlet pipe, and at the same time, the solvent oil is sprayed onto the inner wall of the distillation kettle body through the flushing port after flowing through the connecting tube and the connecting port, thereby further improving the cleaning efficiency;

[0049] 3. In the utility model, through the setting of the reciprocating lifting mechanism, the rotation of the driving rod can drive the fourth gear to rotate, and at the same time, the meshing of the fourth gear and the third gear drives the third gear to rotate, and then the meshing of the third gear and the fourth gear drives the fourth gear and the reciprocating screw to rotate, so that the lifting shell and the support tube can be driven to lift and lower reciprocate through the cooperation of the reciprocating screw and the screw nut, so as to facilitate the comprehensive cleaning of the inner wall of the distillation kettle body;

[0050] 4. In the utility model, through the arrangement of the distillation kettle body, the supporting shell, the supporting port, the lifting shell, the supporting tube, the first supporting block, the second supporting block, the cleaning roller, the scraper, the rotating mechanism and the reciprocating lifting mechanism, it is convenient to clean the inner wall of the distillation kettle body by moving the cleaning bristles and the scraper, and at the same time, spraying solvent oil during the cleaning process improves the cleaning efficiency. The solvent oil can flow along the inner wall of the distillation kettle body to the bottom of the distillation kettle body, so that the crystals at the bottom of the distillation kettle body can be dissolved by the solvent oil, which solves the problem of low cleaning efficiency of the distillation kettle body after use in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0052] Figure 1 It is a schematic diagram of the structure of the utility model;

[0053] Figure 2 This is a schematic diagram of the cross-sectional structure of the utility model;

[0054] Figure 3 This is a schematic diagram of a new structure of a cross-section of the practical rotating mechanism;

[0055] Figure 4 It is a schematic diagram of the structure of the reciprocating lifting mechanism and the rotating mechanism of the utility model.

[0056] In the figure: 1. distillation kettle body; 2. supporting shell; 3. lifting shell; 4. supporting tube; 5. first supporting block; 6. second supporting block; 7. cleaning roller; 8. scraper; 9. driving port; 10. first gear; 11. first annular rack; 12. driving rod; 13. first motor; 14. first cavity; 15. first bevel gear; 16. connecting pipe; 17. fixing column; 18. fourth bevel gear; 19. flushing port; 20. water inlet pipe; 21. reciprocating screw; 22. second gear; 23. third gear; 24. fourth gear. DETAILED DESCRIPTION

[0057] The following will be combined with the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0058] like Figure 1~Figure 4As shown, this embodiment proposes a distillation kettle for extracting concentrated formaldehyde by steam return water, comprising a distillation kettle body 1, a support shell 2, a support port, a lifting shell 3, a support tube 4, a first support block 5, a second support block 6, a cleaning roller 7, a scraper 8, a rotating mechanism and a reciprocating lifting mechanism, the support shell 2 is fixedly arranged on the distillation kettle body 1, the support port is opened between the support shell 2 and the distillation kettle body 1, the lifting shell 3 is slidably arranged in the support shell 2, the support tube 4 is rotatably arranged on the inner top wall of the lifting shell 3, the support tube 4 penetrates the side wall of the lifting shell 3 and the support port and extends into the distillation kettle body 1, the support tube 4 is sealed at one end away from the lifting shell 3, and the support Two first support blocks 5 are fixedly arranged on the side wall of the support tube 4, and the second support block 6 is fixedly arranged on the side wall of the support tube 4 away from the support shell 2. The cleaning roller 7 is rotatably arranged between one of the first support blocks 5 and the second support block 6. The cleaning roller 7 is evenly distributed with cleaning bristles, and the cleaning bristles are in contact with the inner wall of the distillation kettle body 1. The scraper 8 is fixedly arranged between the other first support block 5 and the second support block 6, and the scraper 8 is in contact with the inner wall of the distillation kettle body 1. The rotating mechanism is arranged in the support shell 2 for controlling the rotation of the support tube 4. The reciprocating lifting mechanism is arranged in the support shell 2 for controlling the lifting shell 3 and the support tube 4 to perform reciprocating lifting and lowering.

[0059] Among them, the rotating mechanism includes a driving port 9, a first gear 10, a first annular rack 11, a driving rod 12 and a first motor 13. The driving port 9 is opened on the lifting shell 3. The first gear 10 and the driving port 9 are rotationally arranged in the lifting shell 3 corresponding to the rotation of the first gear 10. The first annular rack 11 is fixedly arranged on the support tube 4. The first gear 10 is meshed with the first annular rack 11. The driving rod 12 is rotationally arranged in the support shell 2. The driving rod 12 passes through the driving port 9 and the first gear 10. The driving rod 12 is slidingly connected to the first gear 10. The first motor 13 is fixedly arranged on the support shell 2, and the output end of the first motor 13 is fixedly connected to the driving rod 12.

[0060] Specifically, the operator controls the operation of the first motor 13, and the operation of the first motor 13 can drive the first gear 10 to rotate. At the same time, the engagement of the first gear 10 with the first annular rack 11 drives the support tube 4 to rotate. At the same time, the first support block 5 and the second support block 6 drive the cleaning roller 7 and the scraper 8 to clean the inner wall of the distillation kettle body 1.

[0061] Among them, it also includes an auxiliary cleaning mechanism, which is arranged in the support tube 4 and is used to assist in cleaning the inner wall of the distillation kettle body 1. The auxiliary cleaning mechanism includes a first cavity 14, a first bevel gear 15, a connecting pipe 16, a fixed column 17 and a flushing mechanism. The first cavity 14 is opened in the first support block 5 near the side of the cleaning roller 7. The first bevel gear 15 is fixedly arranged on the inner bottom wall of the first cavity 14. A connecting column is fixedly arranged between the first bevel gear 15 and the cleaning roller 7. The connecting pipe 16 is rotatably arranged between the support tube 4 and the first cavity 14. A second bevel gear is fixedly arranged on one end of the side wall of the connecting pipe 16 near the first cavity 14, and a third bevel gear is fixedly arranged on one end of the side wall of the connecting pipe 16 away from the first cavity 14, wherein the second bevel gear is meshed with the first bevel gear 15. The fixed column 17 is fixedly arranged on the inner top wall of the lifting shell 3. A fourth bevel gear 18 is fixedly arranged on the fixed column 17, and the fourth bevel gear 18 is meshed with the third bevel gear. The flushing mechanism is arranged on the lifting shell 3 to flush the inner wall of the distillation kettle body 1.

[0062] Specifically, the rotation of the support tube 4 can drive the third bevel gear to move around the fourth bevel gear 18, and at the same time, the meshing of the third bevel gear and the fourth bevel gear 18 can drive the connecting tube 16 and the second bevel gear to rotate. At the same time, the meshing of the first bevel gear 15 and the second bevel gear can drive the first bevel gear 15 and the cleaning roller 7 to rotate, thereby further improving the cleaning effect of the cleaning brush on the inner wall of the distillation kettle body 1.

[0063] Among them, the flushing mechanism includes a flushing port 19, a connecting port and a water inlet pipe 20. The flushing ports 19 are evenly distributed on the cleaning roller 7. The connecting port is opened on the fixed column 17. The two ends of the connecting port are respectively connected to the flushing port 19 and the first cavity 14. The water inlet pipe 20 is arranged on the support shell 2. The water inlet pipe 20 penetrates the support shell 2 and extends into the support tube 4.

[0064] Specifically, during the cleaning process, solvent oil can be introduced into the support tube 4 through the water inlet pipe 20. At the same time, the solvent oil flows through the connecting pipe 16 and the connecting port and then sprays onto the inner wall of the distillation kettle body 1 through the flushing port 19, thereby further improving the cleaning efficiency.

[0065] Among them, the reciprocating lifting mechanism includes a fixed port, a reciprocating screw 21 and a synchronous rotation mechanism. A plurality of fixed ports are opened on the lifting shell 3, and a screw nut is fixedly arranged in each fixed port. The reciprocating screw 21 is arranged in plurality, and a plurality of reciprocating screws 21 are rotatably arranged in the support shell 2. The reciprocating screw 21 passes through the screw nut. The synchronous rotation mechanism is arranged in the support shell 2 for controlling the reciprocating screw 21 to rotate synchronously. The synchronous rotation mechanism includes a second cavity, a second gear 22, a third gear 23 and a fourth gear 24. The second cavity is opened on the inner top wall of the support shell 2. A plurality of second gears 22 are rotatably arranged in the second cavity. The second gear 22 is fixedly connected to the reciprocating screw 21. The third gear 23 is rotatably arranged in the second cavity. The third gear 23 is meshed with the second gear 22. The fourth gear 24 is rotatably arranged in the second cavity. The fourth gear 24 is meshed with the third gear 23. The fourth gear 24 is fixedly connected to the driving rod 12.

[0066] Specifically, the rotation of the driving rod 12 can drive the fourth gear 24 to rotate, and at the same time, the third gear 23 is driven to rotate through the engagement of the fourth gear 24 with the third gear 23, and then the fourth gear 24 and the reciprocating screw 21 are driven to rotate through the engagement of the third gear 23 with the fourth gear 24, so that the lifting shell 3 and the support tube 4 can be driven to reciprocate and rise and fall through the cooperation of the reciprocating screw and the screw nut, thereby facilitating a comprehensive cleaning of the inner wall of the distillation kettle body 1.

[0067] In this embodiment, after use, the operator controls the first motor 13 to work, and the work of the first motor 13 can drive the first gear 10 to rotate, and at the same time, the meshing of the first gear 10 and the first annular rack 11 can drive the support tube 4 to rotate, and at the same time, the first support block 5 and the second support block 6 drive the cleaning roller 7 and the scraper 8 to clean the inner wall of the distillation kettle body 1, and at the same time, the rotation of the support tube 4 can drive the third bevel gear to move around the fourth bevel gear 18, and at the same time, the meshing of the third bevel gear and the fourth bevel gear 18 can drive the connecting tube 16 and the second bevel gear to rotate, and at the same time, the meshing of the first bevel gear 15 and the second bevel gear can drive the first bevel gear 15 and the cleaning roller 7 to rotate, thereby further improving the cleaning effect of the cleaning brush on the inner wall of the distillation kettle body 1. During the cleaning process, Solvent oil is introduced into the support tube 4 through the water inlet pipe 20, and at the same time, the solvent oil is sprayed onto the inner wall of the distillation kettle body 1 through the flushing port 19 after circulating through the connecting pipe 16 and the connecting port, and the solvent oil can flow along the inner wall of the distillation kettle body 1 to the bottom of the distillation kettle body 1, so that it is convenient to dissolve the crystals at the bottom of the distillation kettle body 1 through the solvent oil, and at the same time, the rotation of the driving rod 12 can drive the fourth gear 24 to rotate, and at the same time, the third gear 23 is driven to rotate through the engagement of the fourth gear 24 with the third gear 23, and then the fourth gear 24 and the reciprocating screw 21 are driven to rotate through the engagement of the third gear 23 with the fourth gear 24, so that the lifting shell 3 and the support tube 4 can be driven to lift and lower reciprocately through the cooperation of the reciprocating screw and the screw nut, so as to facilitate comprehensive cleaning of the inner wall of the distillation kettle body 1.

[0068] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A distillation kettle for extracting concentrated and diluted formaldehyde by using steam backwater, characterized in that: include: Still body (1); A supporting shell (2), wherein the supporting shell (2) is fixedly arranged on the distillation kettle body (1); A support opening, the support opening being provided between the support shell (2) and the distillation kettle body (1); A lifting shell (3), the lifting shell (3) being slidably arranged in the supporting shell (2); A support tube (4), the support tube (4) being rotatably arranged on the inner top wall of the lifting shell (3), the support tube (4) penetrating the side wall of the lifting shell (3) and the support opening and extending into the distillation kettle body (1); A first support block (5), two of the first support blocks (5) being fixedly arranged on the side wall of the support tube (4); a second support block (6), the second support block (6) being fixedly arranged on a side wall of the support tube (4) away from the support shell (2); a cleaning roller (7), the cleaning roller (7) being rotatably arranged between one of the first supporting blocks (5) and the second supporting block (6), the cleaning roller (7) being evenly distributed with cleaning bristles, the cleaning bristles being in contact with the inner wall of the distillation kettle body (1); a scraper (8), the scraper (8) being fixedly arranged between the other first support block (5) and the second support block (6), the scraper (8) being in contact with the inner wall of the distillation kettle body (1); a rotating mechanism, the rotating mechanism being arranged in the supporting shell (2) and being used to control the supporting tube (4) to rotate; A reciprocating lifting mechanism, the reciprocating lifting mechanism is arranged in the supporting shell (2) and is used to control the lifting shell (3) and the supporting tube (4) to perform reciprocating lifting.

2. A distillation kettle for extracting concentrated and diluted formaldehyde by using steam backwater according to claim 1, characterized in that: The rotating mechanism comprises: A driving port (9), the driving port (9) being provided on the lifting shell (3); A first gear (10), the first gear (10) being arranged in the lifting housing (3) so as to rotate correspondingly to the driving port (9); a first annular rack (11), the first annular rack (11) being fixedly arranged on the support tube (4); Wherein, the first gear (10) is meshed with the first annular rack (11); a driving rod (12), the driving rod (12) being rotatably disposed in the supporting shell (2), the driving rod (12) penetrating the driving port (9) and the first gear (10); Wherein, the driving rod (12) is slidably connected to the first gear (10); A first motor (13), wherein the first motor (13) is fixedly arranged on the supporting shell (2), and an output end of the first motor (13) is fixedly connected to the driving rod (12).

3. A distillation kettle for extracting concentrated and diluted formaldehyde by using steam backwater according to claim 2, characterized in that: It also includes an auxiliary cleaning mechanism, which is arranged in the support tube (4) and is used to assist in cleaning the inner wall of the distillation kettle body (1). The auxiliary cleaning mechanism includes: A first cavity (14), the first cavity (14) being opened in the first supporting block (5) on a side close to the cleaning roller (7); a first bevel gear (15), the first bevel gear (15) being fixedly arranged on the inner bottom wall of the first cavity (14), and a connecting column being fixedly arranged between the first bevel gear (15) and the cleaning roller (7); a connecting tube (16), the connecting tube (16) being rotatably disposed between the supporting tube (4) and the first cavity (14), a second bevel gear being fixedly disposed on one end of a side wall of the connecting tube (16) close to the first cavity (14), and a third bevel gear being fixedly disposed on one end of a side wall of the connecting tube (16) away from the first cavity (14); Wherein, the second bevel gear is meshed with the first bevel gear (15); A fixed column (17), the fixed column (17) being fixedly arranged on the inner top wall of the lifting shell (3), a fourth bevel gear (18) being fixedly arranged on the fixed column (17), the fourth bevel gear (18) being meshed with the third bevel gear; A flushing mechanism, the flushing mechanism is arranged on the lifting shell (3) and is used to flush the inner wall of the distillation kettle body (1).

4. A distillation kettle for extracting concentrated and diluted formaldehyde by using steam backwater according to claim 3, characterized in that: The flushing mechanism comprises: Flushing ports (19), the flushing ports (19) being evenly distributed on the cleaning roller (7); A connection port, the connection port being provided on the fixing column (17), and the two ends of the connection port being respectively connected to the flushing port (19) and the first cavity (14); A water inlet pipe (20), the water inlet pipe (20) being arranged through the support shell (2), the water inlet pipe (20) penetrating the support shell (2) and extending into the support pipe (4).

5. A distillation kettle for extracting concentrated and diluted formaldehyde by using steam backwater according to claim 4, characterized in that: The reciprocating lifting mechanism comprises: A fixing opening, wherein a plurality of the fixing openings are provided on the lifting shell (3), and a lead screw nut is fixedly arranged in each of the fixing openings; a reciprocating screw (21), wherein the reciprocating screw (21) is provided in plurality, the plurality of reciprocating screws (21) are rotatably arranged in the support housing (2), and the reciprocating screw (21) passes through the screw nut; A synchronous rotation mechanism, the synchronous rotation mechanism is arranged in the support housing (2) and is used to control the reciprocating screw (21) to rotate synchronously.

6. A distillation kettle for extracting concentrated and diluted formaldehyde by using steam backwater according to claim 5, characterized in that: The synchronous rotation mechanism comprises: a second cavity, the second cavity being opened on the inner top wall of the supporting shell (2); A second gear (22), wherein a plurality of second gears (22) are rotatably arranged in the second cavity, and the second gear (22) is fixedly connected to the reciprocating screw (21); a third gear (23), the third gear (23) being rotatably disposed in the second cavity, the third gear (23) being meshed with the second gear (22); A fourth gear (24), the fourth gear (24) being rotatably disposed in the second cavity, the fourth gear (24) being meshed with the third gear (23), and the fourth gear (24) being fixedly connected to the driving rod (12).

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