An auxiliary system for shaft seals of a scraper evaporator

Abstract

The application relates to the technical field of scraper evaporators, in particular to an auxiliary system of a shaft seal of a scraper evaporator, which comprises a magnetic fluid sealing device, a pressure measuring port and a detection port are arranged on the side wall of the magnetic fluid sealing device, a transmission shaft of the magnetic fluid sealing device is coaxially fixed with a shaft of the scraper evaporator; an air inlet pipe is connected with an air inlet port of the magnetic fluid sealing device; a pressure reducing valve is installed on the air inlet pipe; a flow meter is installed on the air inlet pipe; and a detection assembly is used for detecting air pressure in the magnetic fluid sealing device. The application has the effect of reducing the leakage amount of sealing medium, thereby reducing the possibility of damaging the working environment inside the scraper evaporator.

Description

Technical Field

[0001] This application relates to the field of scraped evaporator technology, and in particular to an auxiliary system for the shaft seal of a scraped evaporator. Background Technology

[0002] A scraped evaporator is a device that uses heating and evaporation principles to concentrate and dry materials. To improve the operational stability of a scraped evaporator, shaft sealing is usually required.

[0003] Existing shaft sealing methods for scraped evaporators include wet double-end face mechanical seals and dry double-end face mechanical seals. For wet double-end face mechanical seals, a sealing liquid tank is required. The sealing liquid inlet and outlet of the tank are connected to the corresponding sealing liquid inlet and outlet of the mechanical seal to form a loop. The sealing liquid tank is filled with sealing liquid. During mechanical seal operation, the tank is pressurized to force the sealing liquid to circulate thermosiphonically within the mechanical seal loop, or a circulation pump is used for forced circulation. The sealing liquid is used to seal the end faces of the mechanical seal. For dry double-end face mechanical seals, gas is supplied by a gas source, passes through a filter and pressure reducing valve, and enters the end faces of the double-end face mechanical seal. The system is equipped with a gas flow meter and pressure transmitter to monitor the isolation gas inlet. The flow rate measured by the gas flow meter is the flow rate of isolation gas leaking from the end face into the vessel.

[0004] In the aforementioned wet double-end mechanical seal, the sealing fluid will leak into the scraper evaporator as the end face wears down; in the dry double-end mechanical seal, the pressure of the isolation gas is generally higher than the working pressure inside the vessel. Therefore, in this shaft seal scheme, the leakage of the isolation gas will inevitably increase as the sealing end face wears down, which is an area that needs improvement. Summary of the Invention

[0005] In order to reduce the risk of sealing medium entering the evaporator and disrupting the working environment due to wear on the end faces of the double-end mechanical seal, this application provides an auxiliary system for the shaft seal of a scraper evaporator.

[0006] This application provides an auxiliary system for the shaft seal of a scraped evaporator, which adopts the following technical solution: An auxiliary system for the shaft seal of a scraped evaporator includes, A magnetic fluid sealing device, wherein a pressure measuring port and a detection port are provided on the side wall of the magnetic fluid sealing device, and the drive shaft of the magnetic fluid sealing device is fixed coaxially with the shaft of the scraped evaporator; An air inlet pipe, which is connected to the air inlet of the magnetohydrodynamic sealing device; A pressure reducing valve, which is installed on the intake pipe; A flow meter, which is mounted on the air inlet pipe; A detection component for detecting the air pressure in the magnetohydrodynamic sealing device.

[0007] By adopting the above technical solution, the nitrogen source on the sealing auxiliary system is connected. Nitrogen enters the magnetic fluid sealing device through a pressure reducing valve (maintaining the gas source pressure higher than the working pressure inside the vessel + 0.05 MPa) and a flow meter. Because the nitrogen pressure is slightly higher than the working pressure inside the scraped evaporator, the gas evaporated from the scraped evaporator will be purged by nitrogen at the sealing point, preventing it from accumulating there. The detection component detects the gas pressure inside the magnetic fluid sealing device, thus facilitating the control of the incoming nitrogen pressure. The detection port facilitates the detection of gas in the magnetic fluid sealing device. The pressure measuring port facilitates the detection of the nitrogen pressure entering the inner cavity of the magnetic fluid sealing device, improving system safety. The fluid sealing device effectively seals the magnetic fluid within the cavity, thus preventing leakage. It does not rely on external liquids or gases for sealing, therefore there is no risk of leakage when the magnetic fluid seal is working normally, thereby reducing the possibility of damaging the internal working environment of the evaporator.

[0008] Optionally, the detection assembly includes a gas detector and a pressure transmitter. The gas detector and the magnetohydrodynamic sealing device are connected to the detection port via a conduit, and the pressure transmitter is connected to the pressure measuring port via a conduit.

[0009] By adopting the above technical solution, when the magnetic fluid sealing device fails, gas will leak inside the vessel. The gas detector is set to detect the gas leak in time, reducing safety problems caused when the working medium inside the vessel is a toxic or harmful substance. The gas emitted by the scraped evaporator is monitored by a pressure transmitter at the seal. If the evaporated gas enters the middle of the magnetic fluid sealing device, it will be detected by the gas detector, thereby improving the safety of the shaft seal auxiliary system.

[0010] Optionally, the magnetohydrodynamic sealing device includes a cooling box, and a cooling device is installed on the air inlet pipe. The air inlet pipe is connected to the cooling box, and the cooling box is connected to the pressure measuring port.

[0011] By adopting the above technical solution, the cooling device cools the nitrogen in the inlet pipe, so that the gas entering the cooling box is in a cooled state, resulting in a lower temperature inside the cooling box. Under the action of the cooling box, the temperature inside the magnetic fluid sealing device is reduced, thereby reducing the possibility of high temperature interfering with the magnetic fluid inside the magnetic fluid sealing device, and thus reducing the possibility of demagnetization of the magnetic fluid inside the magnetic fluid sealing device.

[0012] Optionally, a cavity is formed between the magnetic fluid sealing device and the scraper evaporator, the air inlet pipe is connected to the cavity, and a connecting pipe is connected between the cooling box and the cavity.

[0013] By adopting the above technical solution, the nitrogen in the intake pipe is cooled by the cooling device and then enters the cavity. The gas evaporated by the scraper evaporator enters the cavity. The nitrogen in the intake pipe purges the gas evaporated by the scraper evaporator in the cavity, reducing the possibility of accumulation at the seal. The nitrogen entering the cavity enters the cooling box through the connecting pipe, and the nitrogen cools the cooling box, so that the nitrogen flowing out of the intake pipe has a dual function.

[0014] Optionally, a branch pipe is connected to the side wall of the air inlet pipe, and the branch pipe is connected to the inner cavity of the cavity. The connection between the branch pipe and the air inlet pipe is located on the side of the cooling device away from the magnetic fluid cooling device. A first valve is installed on the air inlet pipe, and a second valve is installed on the branch pipe. The first valve is used to control the gas in the air inlet pipe to enter the cooling device.

[0015] By adopting the above technical solution, the second valve is opened at the same time as the scraper evaporator is started, and nitrogen gas is introduced into the cavity through the branch pipe. At this time, it is not necessary to turn on the cooling device. When the scraper evaporator has been running for a long time, the second valve is closed, the first valve is opened, and the cooling device is turned on. The nitrogen gas entering the inlet pipe has a lower temperature under the cooling device, which makes it easier to reduce the temperature in the cooling box and saves energy.

[0016] Optionally, the magnetic fluid sealing device is equipped with a detection device for detecting the internal temperature, and a PLC system is installed on the magnetic fluid sealing device. The detection device, the first valve, and the second valve are all electrically connected to the PLC system.

[0017] By adopting the above technical solution, the detection device is set to detect the temperature inside the magnetic fluid sealing device. When the temperature inside the magnetic fluid sealing device exceeds the set temperature, the signal is transmitted to the PLC system. The PLC system controls the opening and closing of the first valve and the second valve according to the transmitted signal, making the auxiliary system more intelligent.

[0018] Optionally, a fixing seat is fixed to the side wall of the magnetic fluid sealing device by fasteners. The fixing seat is fixedly connected to the side wall of the scraped evaporator. A limiting groove is formed on the side wall of the fixing seat. A sealing ring is fixed on the inner wall of the limiting groove. The sealing ring abuts against the side wall of the magnetic fluid sealing device.

[0019] By adopting the above technical solution, a limiting groove is opened on the fixed seat, and a fixed sealing ring is snapped into the limiting groove. The setting of the sealing ring reduces the gap between the fixed seat and the magnetic fluid sealing device, thereby improving the sealing performance of the shaft seal auxiliary device.

[0020] Optionally, a connector is fixed on the side wall of the magnetic fluid sealing device, and the connector is installed at the positions of the air inlet, pressure measuring port and detection port of the magnetic fluid sealing device.

[0021] By adopting the above technical solution, the connection head is designed to facilitate the connection of pipelines to the magnetic fluid sealing device by the operator, thereby making the assembly of the auxiliary system of the shaft seal of the scraped evaporator more convenient.

[0022] Optionally, all the connectors are threadedly connected to the side wall of the magnetohydrodynamic sealing device.

[0023] By adopting the above technical solution, the connector can be easily disassembled, thereby facilitating the maintenance of the magnetohydrodynamic sealing device.

[0024] Optionally, a plurality of hanging rings are fixed on the side wall of the magnetic fluid sealing device, and the hanging rings are located at the top of the magnetic fluid sealing device.

[0025] By adopting the above technical solution, the hanging ring facilitates the hanging of the magnetic fluid sealing device, thereby reducing the damage to the pipeline caused by the gravity of the magnetic fluid sealing device.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. The inlet pipe facilitates the introduction of nitrogen into the magnetic fluid sealing device. The pressure reducing valve allows operators to control the pressure of the nitrogen entering the device. The detection device monitors the gas pressure within the sealing device. Nitrogen enters the sealing device through the pressure reducing valve and flow meter, and its pressure needs to be slightly higher than the working pressure in the scraper evaporator for proper operation. Gas evaporated from the scraper evaporator is purged at the seal by nitrogen, reducing accumulation. The magnetic fluid sealing device minimizes leakage of the sealing medium, thereby reducing the possibility of disrupting the working environment within the device.

[0027] 2. When the magnetic fluid sealing device operates for a short time or at a low temperature, open the second valve and close the first valve, allowing nitrogen gas to enter the magnetic fluid sealing device through the inlet pipe and branch pipe. When the scraper evaporator operates for a long time or at a high temperature inside the magnetic fluid sealing device, close the second valve and open the first valve to activate the cooling device. Nitrogen gas enters the cooling device through the inlet pipe, where it is cooled to a lower temperature. Once inside the magnetic fluid sealing device, the nitrogen gas lowers the temperature, reducing the likelihood of demagnetization and thus minimizing leakage of the sealing medium. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the auxiliary system for the shaft seal in the embodiments of this application.

[0029] Figure 2 This is a schematic diagram of the structure of the magnetohydrodynamic sealing device in the embodiment of this application.

[0030] Figure 3 This is a partial cross-sectional view of the magnetohydrodynamic sealing device in the embodiments of this application, used to show the cooling box inside the magnetohydrodynamic sealing device.

[0031] Reference numerals: 1. Magnetohydrodynamic sealing device; 2. Pressure measuring port; 3. Detection port; 4. Inlet pipe; 5. Pressure reducing valve; 6. Flow meter; 7. Detection component; 71. Gas detector; 72. Pressure transmitter; 8. Cooling box; 9. Cooling device; 11. Connecting pipe; 12. Branch pipe; 13. First valve; 14. Second valve; 15. Detection device; 17. Fixing seat; 18. Limiting groove; 19. Sealing ring; 20. Connector; 21. Support frame; 22. Mounting plate; 23. Hanging ring. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0033] This application discloses an auxiliary system for the shaft seal of a scraped evaporator.

[0034] Reference Figure 1 An auxiliary system for the shaft seal of a scraped evaporator includes a magnetic fluid sealing device 1 and an air inlet pipe 4. Several connectors 20 are fixed to the side wall of the magnetic fluid sealing device 1 by bolts. The end of the air inlet pipe 4 is threadedly fixed to the connectors 20. The connectors 20 are provided to facilitate the operator to fix the air inlet pipe 4 to the side wall of the magnetic fluid sealing device 1.

[0035] Reference Figure 1 The auxiliary system for the shaft seal of the scraped evaporator also includes a support frame 21, a pressure reducing valve 5, and a flow meter 6. A mounting plate 22 is bolted to the side wall of the support frame 21. The pressure reducing valve 5 and the flow meter 6 are both bolted to the side wall of the mounting plate 22. The pressure reducing valve 5 and the flow meter 6 are both installed on the inlet pipe 4. Nitrogen gas is introduced into the inlet pipe 4 through the inlet port of the inlet pipe 4. After passing through the pressure reducing valve 5 (keeping the gas source pressure higher than the working pressure inside the vessel + 0.5 MPa) and the flow meter 6, the nitrogen gas enters the magnetic fluid sealing device 1. The setting of the pressure reducing valve 5 and the flow meter 6 facilitates the control of the pressure of the nitrogen gas entering the inlet pipe 4.

[0036] Reference Figure 2 A hanging ring 23 is threadedly fixed on the top wall of the magnetic fluid sealing device 1. The hanging ring 23 makes it easy for workers to hang the magnetic fluid sealing device 1, thereby reducing the possibility of damage to surrounding pipelines caused by the gravity of the magnetic fluid sealing device 1.

[0037] Reference Figure 2 and Figure 3 A fixing seat 17 is bolted to the side wall of the magnetic fluid sealing device 1. The scraped evaporator is bolted to the fixing seat 17. A limiting groove 18 is formed on the side wall of the fixing seat 17. A sealing ring 19 is snapped and fixed on the inner wall of the limiting groove 18. The side wall of the sealing ring 19 abuts against the side wall of the scraped evaporator. In this application, the sealing ring 19 is preferably made of rubber. The setting of the sealing ring 19 reduces the gap between the fixing seat 17 and the scraped evaporator, thereby making the connection between the scraped evaporator and the magnetic fluid sealing device 1 have good sealing performance.

[0038] Reference Figure 3 A cavity is formed between the magnetic fluid sealing device 1 and the scraped evaporator, and the gas generated by the magnetic fluid sealing device 1 enters the cavity. A cooling box 8 is snapped and fixed on the inner wall of the magnetic fluid sealing device 1. The box containing the magnetic fluid in the magnetic fluid sealing device 1 is located in the cooling box 8. The setting of the cooling box 8 facilitates the introduction of cooling gas. The lower temperature of the cooling box 8 cools down the high temperature of the magnetic fluid, thereby reducing the possibility of magnetic fluid failure.

[0039] Reference Figure 1 and Figure 3 A connecting pipe 11 is connected to the side wall of the cooling box 8, and the end of the connecting pipe 11 away from the cooling box 8 is connected to the cavity. The end of the air inlet pipe 4 is fixedly connected to the end of the connector 20, connecting the air inlet pipe 4 to the inner cavity of the cavity. A cooling device 9 is installed on the outer wall of the air inlet pipe 4. The cooling device 9 cools the gas in the air inlet pipe 4, so that the temperature of the gas entering the cavity is lower. When the gas in the cavity enters the cooling box 8 through the connecting pipe 11, it is convenient to reduce the temperature of the magnetic fluid.

[0040] Reference Figure 1 A branch pipe 12 is connected to the side wall of the intake pipe 4. One end of the branch pipe 12 is connected to the inner cavity of the intake pipe 4, and the other end is connected to the inner cavity of the cavity through a connector 20. A second valve 14 is installed on the branch pipe 12 to restrict the flow of gas in the branch pipe 12. A first valve 13 is installed on the intake pipe 4 to restrict the flow of gas in the intake pipe 4. The first valve 13 is located between the connection between the intake pipe 4 and the branch pipe 12 and the cooling device 9. When the operator opens the second valve 14 and closes the first valve 13, the nitrogen gas entering the intake pipe 4 enters the cavity through the branch pipe 12. When the second valve 14 is closed and the first valve 13 is opened, the nitrogen gas entering the intake pipe 4 enters the cavity through the intake pipe 4, facilitating the cooling of the nitrogen gas in the intake pipe 4 by the cooling device 9.

[0041] Reference Figure 1When the working time of the magnetic fluid sealing device 1 is short or the temperature of the magnetic fluid is low, the second valve 14 is opened and the first valve 13 is closed. The nitrogen gas entering the air inlet pipe 4 enters the cavity through the branch pipe 12. The nitrogen gas purges the gas generated by the magnetic fluid sealing device 1 in the cavity to prevent gas phase polymerization or condensation in the cavity, thereby reducing the impact on the magnetic fluid sealing device 1. When the working time of the magnetic fluid sealing device 1 is long or the temperature of the magnetic fluid is high, the second valve 14 is closed and the first valve 13 is opened. The cooling device 9 is turned on. The temperature of the nitrogen gas entering the air inlet pipe 4 is reduced under the action of the cooling device 9. At this time, the gas in the air inlet pipe 4 enters the cavity, which both purges the gas in the cavity and enters the cooling box 8 through the cavity to cool the magnetic fluid.

[0042] Reference Figure 1 and Figure 3 The magnetic fluid sealing device 1 is equipped with a detection device 15 for detecting the internal temperature of the magnetic fluid sealing device 1. In this application, the detection device 15 is preferably a temperature sensor. The magnetic fluid sealing device 1 is equipped with a PLC system. The detection device 15, the first valve 13 and the second valve 14 are all electrically connected to the PLC system. The detection device 15 detects the temperature of the inner cavity of the magnetic fluid sealing device 1. When the temperature of the inner cavity of the magnetic fluid sealing device 1 reaches the limit temperature, it transmits the signal to the PLC system. The PLC system controls the opening and closing of the first valve 13 and the second valve 14, thereby facilitating the control of the temperature of the nitrogen gas entering the cavity and reducing the energy consumption of the cooling device 9.

[0043] Reference Figure 1 A detection component 7 is provided on the side wall of the mounting plate 22. In this application, the detection component 7 includes a gas detector 71 and a pressure transmitter 72. The gas detector 71 and the pressure transmitter 72 are fixed to the side wall of the mounting plate 22 by bolts. A pressure measuring port 2 and a detection port 3 are provided on the side wall of the magnetic fluid sealing device 1. A connector 20 is fixed at the position of the pressure measuring port 2 and the detection port 3. The gas detector 71 is fixedly connected to the connector 20 at the position of the detection port 3 through a conduit. When the working medium in the vessel is toxic and harmful, in order to detect the gas leakage in the vessel as early as possible in order to avoid the failure of the magnetic fluid seal, the safety of the auxiliary system of the shaft seal of the scraper evaporator is improved.

[0044] Reference Figure 1The pressure transmitter 72 is fixedly connected to the connector 20 at the pressure measuring port 2 via a conduit. The flow rate of the flow meter 6 is the flow rate of the isolation gas leaking into the vessel from the end face. Generally, the pressure of the isolation gas is higher than the working pressure inside the vessel. Therefore, in this shaft seal scheme, the leakage of the isolation gas will inevitably increase with the wear of the sealing end face. For scraped evaporators, especially in high vacuum conditions, the entry of the isolation gas into the evaporator will disrupt the working environment and increase the load on the vacuum system. Since most of the isolation gas is non-condensable, it can damage the vacuum system in severe cases. When the working pressure inside the scraped evaporator is lower than the absolute pressure by 1 kPa, the leakage of the isolation gas will severely exacerbate the load on the vacuum system. When the working pressure is lower than the absolute pressure by 100 Pa, this shaft seal scheme is not applicable. Therefore, the setting of the pressure transmitter 72 improves the safety of the auxiliary system of the shaft seal of the scraped evaporator.

[0045] The implementation principle of the auxiliary system for the shaft seal of a scraped evaporator in this application embodiment is as follows: The nitrogen source on the sealing auxiliary system is connected. Nitrogen gas enters the magnetic fluid sealing device 1 after passing through the pressure reducing valve 5 and the flow meter 6. Because the pressure of the nitrogen gas is slightly higher than the working pressure inside the scraped evaporator, the gas evaporated by the scraped evaporator will be purged at the seal by the nitrogen gas, preventing it from accumulating at the seal. The gas flow rate and pressure here are monitored by the flow meter 6 and the pressure transmitter 72 on the sealing system. The magnetic fluid sealing device 1 effectively seals the magnetic fluid, thereby reducing leakage. The magnetic fluid seal has good corrosion resistance, and the magnetic fluid can maintain stable operation under harsh conditions such as acids, alkalis, and salts, thereby reducing damage to the internal environment of the evaporator.

[0046] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An auxiliary system for the shaft seal of a scraped evaporator, characterized in that: include, A magnetic fluid sealing device (1) is provided with a pressure measuring port (2) and a detection port (3) on its side wall. The drive shaft of the magnetic fluid sealing device (1) is coaxially fixed with the shaft of the scraper evaporator. An air inlet pipe (4) is connected to the air inlet of the magnetic fluid sealing device (1); Pressure reducing valve (5), which is installed on the air inlet pipe (4); A flow meter (6) is installed on the air inlet pipe (4); A detection component (7) is used to detect the air pressure in the magnetohydrodynamic sealing device (1); The magnetic fluid sealing device (1) is provided with a cooling box (8), and a cooling device (9) is installed on the air inlet pipe (4). The air inlet pipe (4) can communicate with the cooling box (8), and the cooling box (8) is connected to the pressure measuring port (2). The magnetic fluid sealing device (1) forms a cavity with the scraped evaporator, the air inlet pipe (4) is connected to the cavity, and the cooling box (8) is connected to the cavity by a connecting pipe (11); A branch pipe (12) is connected to the side wall of the air inlet pipe (4). The branch pipe (12) is connected to the inner cavity of the cavity. The connection between the branch pipe (12) and the air inlet pipe (4) is located on the side of the cooling device (9) away from the magnetic fluid sealing device (1). A first valve (13) is installed on the air inlet pipe (4), and a second valve (14) is installed on the branch pipe (12). The first valve (13) is used to control the gas in the air inlet pipe (4) to enter the cooling device (9).

2. The auxiliary system for the shaft seal of a scraped evaporator according to claim 1, characterized in that: The detection component (7) includes a gas detector (71) and a pressure transmitter (72). The gas detector (71) is connected to the detection port (3) via a conduit to the magnetohydrodynamic sealing device (1), and the pressure transmitter (72) is connected to the pressure measuring port (2) via a conduit.

3. The auxiliary system for the shaft seal of a scraped evaporator according to claim 1, characterized in that: The magnetic fluid sealing device (1) is equipped with a detection device (15) for detecting the internal temperature. The magnetic fluid sealing device (1) is equipped with a PLC system. The detection device (15), the first valve (13) and the second valve (14) are all electrically connected to the PLC system.

4. The auxiliary system for the shaft seal of a scraped evaporator according to claim 1, characterized in that: A fixing seat (17) is fixed on the side wall of the magnetic fluid sealing device (1) by fasteners. The fixing seat (17) is fixedly connected to the side wall of the scraped evaporator. A limiting groove (18) is opened on the side wall of the fixing seat (17). A sealing ring (19) is fixed on the inner wall of the limiting groove (18). The sealing ring (19) abuts against the side wall of the magnetic fluid sealing device (1).

5. The auxiliary system for the shaft seal of a scraped evaporator according to claim 1, characterized in that: A connector (20) is fixed on the side wall of the magnetic fluid sealing device (1), and the connector (20) is installed at the air inlet, pressure measuring port (2) and detection port (3) of the magnetic fluid sealing device (1).

6. The auxiliary system for the shaft seal of a scraped evaporator according to claim 5, characterized in that: All connectors are threaded to the side wall of the magnetic fluid sealing device (1).

7. The auxiliary system for the shaft seal of a scraped evaporator according to claim 1, characterized in that: A number of hanging rings (23) are fixed on the side wall of the magnetic fluid sealing device (1), and the hanging rings (23) are located on the top of the magnetic fluid sealing device (1).

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