A mechanical seal cooling device

Abstract

The present invention discloses a mechanical seal cooling device, aiming to solve the shortcomings of the prior art that when foreign matter enters the sealing cavity of the mechanical seal, the machine can only be shut down for maintenance, and the maintenance is complicated. The present invention solves the above technical problems through the following technical schemes: a liquid inlet main pipe, a liquid return main pipe and a balance main pipe; a mechanical seal flushing and cooling device, including a liquid inlet manifold connected to the liquid inlet main pipe and the balance main pipe, and a liquid return manifold connected to the liquid return main pipe; two pipe openings are arranged on the liquid inlet manifold and the liquid return manifold, and the two pipe openings on the liquid inlet manifold and the liquid return manifold are respectively connected to the top interface and the bottom interface of the mechanical seal; the four pipe openings are externally connected to valves for controlling the opening and closing of the pipe openings. In the present application, the opening and closing of the two pipe openings on the liquid inlet manifold and the liquid return manifold are respectively controlled, so that the foreign matter can be flushed out of the mechanical seal by switching the direction of EG flow.

Description

Technical Field

[0001] The invention relates to the technical field of polyester production, and more specifically, to a mechanical sealing cooling device. Background Art

[0002] In existing polyester production equipment, the stirring shaft of the final polymerization reactor mostly adopts a double-end mechanical seal device. The mechanical seal includes a sealing shell and a sealing component placed in the sealing shell. A heat exchange cavity is formed between the sealing component and the sealing shell. When the mechanical seal is in operation, the heat exchange cavity must be filled with a flushing cooling fluid (ethylene glycol) introduced from the outside that is compatible with the sealed medium. Therefore, the mechanical seal housing is provided with a cooling fluid inlet and a cooling fluid outlet that are connected to the heat exchange cavity. For the mechanical seal for a horizontal machine pump, the coolant inlet is located at the bottom of the mechanical seal, and the coolant outlet is located at the top of the mechanical seal.

[0003] The function of flushing cooling fluid (ethylene glycol) is to cool the sealing end faces to improve the operating conditions between the sealing end faces. Generally, the flushing cooling liquid pressure is required to be 0.1 to 0.2 MPa higher than the sealing chamber pressure.

[0004] In production, mechanical seals are flushed and cooled with ethylene glycol. In order to reduce investment costs, the final polymerization mechanical seals mostly adopt a simplified PLAN54 flushing scheme. That is, a branch pipeline is taken from the fresh EG main pipe of the production system. The fresh EG is pressurized to 1MPa by the delivery pump and reduced to 0.2MPa by the self-operated regulating valve. The ethylene glycol flows through the sealing cavity of the final polymerization mechanical seal and lubricates and cools the sealing end face. The ethylene glycol EG flowing out of the mechanical seal flows into the final polymerization hot well, and the cooling ethylene glycol EG is not recycled.

[0005] After the mechanical seal has been running for a long time, the sealing end face of the mechanical seal will leak due to the wear of the sealing end face and the reduction of the elastic force of the spring. The greater the pressure of the cooling ethylene glycol EG, the greater the leakage of the sealing end face. Severe leakage of the sealing end face will cause the device to shut down.

[0006] In summary, the mechanical seal cooling system in the prior art has the following main deficiencies: (1) It is not sensitive to mechanical seal leakage. Once the mechanical seal is found to be leaking, it can only be repaired by shutting down the machine; (2) The pressure of cooling ethylene glycol EG is fixed, and the pressure cannot be adjusted individually for a single mechanical seal; (3) When the device is shut down, a large amount of crude EG will be generated in order to flush and cool the final polymerization mechanical seal; (4) If foreign matter enters the sealing cavity of the mechanical seal, the machine can only be shut down for maintenance. Summary of the invention

[0007] The present invention overcomes the following deficiencies in the prior art: (1) foreign matter enters the sealing cavity of the mechanical seal, requiring the machine to be shut down for maintenance, which is complicated; (2) EG cannot be recycled, resulting in waste of EG materials; (3) it is not sensitive to mechanical seal leakage, making it difficult to detect mechanical seal leakage; a mechanical seal cooling device is provided, which can detect leakage in a timely manner, discharge foreign matter without shutting down for maintenance, and can recycle EG materials.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solution: a mechanical seal cooling device, comprising: Liquid inlet main pipe, liquid return main pipe and balance main pipe; The mechanical seal flushing and cooling device comprises a liquid inlet manifold connected to the liquid inlet main pipe and the balance main pipe, and a liquid return manifold connected to the liquid return main pipe; the liquid inlet manifold and the liquid return manifold are both provided with two pipe openings, and the two pipe openings on the liquid inlet manifold and the liquid return manifold are respectively connected to the top end interface and the bottom end interface of the mechanical seal; the four pipe openings are externally connected to valves for controlling the opening and closing of the pipe openings; Cooling EG circulation device and recycling EG; The clean EG supply device provides clean EG.

[0009] In the present application, a mechanical seal flushing and cooling device is provided, so that the flow direction of EG in the mechanical seal can be controlled by respectively controlling the opening and closing of the two pipe openings on the liquid inlet manifold and the liquid return manifold, so that when foreign matter is found, the foreign matter can be flushed out of the mechanical seal by switching the direction of EG flow, thereby saving the trouble of stopping the machine for maintenance; by providing a cooling EG circulation device, EG can be cooled and circulated for use, thereby improving the utilization rate of EG; in addition, by providing a clean EG supply device, clean EG can be provided for the mechanical seal.

[0010] Preferably, a liquid inlet flowmeter for detecting the liquid inlet flow rate is provided at the inlet of the liquid inlet manifold, and a liquid return flowmeter for detecting the liquid return flow rate is provided at the outlet of the liquid return manifold.

[0011] By comparing and calculating the difference between the liquid inlet flow meter and the liquid return flow meter, it can be determined whether the mechanical seal has leakage.

[0012] Preferably, the two pipe openings of the liquid inlet manifold are respectively a first pipe opening and a second pipe opening; the first pipe opening is connected to the top end interface, and the second pipe opening is connected to the bottom end interface; The two pipe openings of the liquid return manifold are respectively the third pipe opening and the fourth pipe opening; the third pipe opening is communicated with the top end interface, and the fourth pipe opening is communicated with the bottom end interface.

[0013] The flow direction of the cooling EG can be changed by controlling the opening and closing of the first pipe port, the second pipe port, the third pipe port and the fourth pipe port, so that the mechanical seal can be flushed and foreign matter can be flushed out, thereby restoring the sealing function of the mechanical seal and extending the service life of the mechanical seal without stopping the machine for maintenance.

[0014] Preferably, the cooling EG circulation device comprises a cooling EG storage tank; The top of the cooling EG storage tank is connected to the clean EG supply device; Cooling A cooling device is provided inside the EG tank; The side wall of the cooling EG storage tank is provided with a cooling EG liquid return pipe port, a cooling EG balance pipe port and a cooling EG liquid inlet pipe port; the cooling EG liquid inlet pipe port is connected to the liquid inlet main pipe, the cooling EG liquid return pipe port is connected to the liquid return main pipe, and the cooling EG balance pipe port is connected to the balance main pipe.

[0015] The recycling of EG is achieved by cooperating with the cooling EG storage tank, the cooling EG liquid return pipe, the cooling EG balance pipe, and the cooling EG liquid inlet pipe. The cooling device can cool the EG, thereby achieving better cooling of the mechanical seal.

[0016] Preferably, the cooling EG liquid inlet pipe port is arranged at one end of the side wall of the cooling EG storage tank close to the bottom.

[0017] After EG flows in from the cooling EG liquid return pipe, the temperature is relatively high. Then the relatively high temperature EG liquid is gradually cooled from the upper part to the lower end of the EG storage tank. Then, the EG is fully cooled in the cooling EG storage tank and flows out from the cooling EG liquid inlet pipe.

[0018] Preferably, a circulation filtering device is provided between the cooling EG liquid inlet pipe port and the liquid inlet main pipe; the cooling EG flows out of the cooling EG storage tank, passes through the circulation filtering device and then flows into the liquid inlet main pipe.

[0019] The cooling EG circulation pump and the filter are combined to form a circulation filtering device, thereby filtering the EG. In addition, the circulation filtering device in this embodiment is arranged in two groups, that is, two groups of cooling EG circulation pumps and filters are arranged in parallel, one group is for normal use, and the other group is for standby use.

[0020] Preferably, the cooling device comprises a spiral cooling coil, and a cooling coil inlet and a cooling coil outlet are respectively provided at both ends of the cooling coil.

[0021] The axis of the spiral cooling coil is arranged parallel to the axis of the cooling EG tank. After the cooling medium enters the cooling coil from the cooling coil inlet, it flows out of the cooling coil from the cooling coil outlet to cool the inside of the cooling EG tank. The spiral cooling coil can improve the cooling efficiency of the EG.

[0022] Preferably, the bottom of the cooling EG storage tank is in a trumpet shape with gradually increasing openings, and a cooling EG drain port is provided at the bottom of the cooling EG storage tank.

[0023] The trumpet-shaped bottom can facilitate the EG to be discharged more cleanly from the cooling EG exhaust port.

[0024] Preferably, the clean EG supply device includes a self-operated regulating valve and a delivery pump. The outlet of the self-operated regulating valve is divided into two paths, which are respectively connected to the liquid inlet main pipe and the cooling EG storage tank.

[0025] By controlling the opening and closing of the two paths, the functions of cleaning EG directly cooling the mechanical seal or cleaning EG indirectly cooling the mechanical seal can be realized.

[0026] Preferably, a liquid level metering header and a liquid level gauge are provided on the top of the cooling EG storage tank.

[0027] The liquid level metering header is sensitive to changes in the total amount of circulating cooling EG, making it easy to determine whether the mechanical seal is leaking.

[0028] Compared with the prior art, the present invention has the following beneficial effects: (1) By controlling the opening and closing of the first pipe port, the second pipe port, the third pipe port and the fourth pipe port, the flow direction of the cooling EG is changed, so that the mechanical seal can be flushed and foreign matter can be flushed out, thereby restoring the sealing function of the mechanical seal and extending the service life of the mechanical seal without stopping the machine for maintenance.

[0029] (2) By adjusting the opening of the isolation valve G at the pressure balance pipe port of the liquid inlet manifold, the cooling EG flow and pressure entering the final polymerization mechanical seal can be adjusted to maintain a lower cooling EG pressure inside the mechanical seal, which is beneficial to reducing the leakage of the mechanical seal and extending the service life of the mechanical seal.

[0030] (3) By comparing and calculating the difference between the liquid inlet flow meter and the liquid return flow meter, it can be determined whether the mechanical seal has leakage.

[0031] (4) By setting up a cooling EG circulation device, EG can be cooled and recycled, thereby improving the utilization rate of EG and reducing material waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0033] Figure 2 It is a simplified structural diagram of the mechanical seal flushing and cooling device of the present invention.

[0034] Figure 3It is a schematic structural diagram of the liquid inlet header and the liquid return header of the present invention.

[0035] Figure 4 A schematic structural diagram of the liquid inlet header and the liquid return header of the present invention from another angle.

[0036] Figure 5 It is a schematic diagram of the assembly of the cooling EG storage tank and the liquid level metering header of the present invention.

[0037] In the figure: 1, mechanical seal flushing cooling system, 1-1, mechanical seal, 1-2, liquid inlet manifold, 1-3, liquid return manifold, 1-4, balance manifold, 1-5, liquid inlet header; 1-51, first pipe opening, 1-52, second pipe opening, 1-53, liquid inlet pipe opening, 1-54, pressure balance pipe opening; 1-6, liquid return manifold, 1-61, fourth pipe opening, 1-62, third pipe opening, 1-63, liquid outlet pipe opening; 1-7, liquid inlet flow meter, 1-8, liquid return flow meter; 2. Cooling EG circulation system, 2-1. Cooling EG storage tank, 2-11. Cooling EG storage tank shell, 2-12. Cooling coil, 2-12-1 cooling coil inlet, 2-12-2 cooling coil outlet, 2-13. Cleaning EG inlet; 2-14, liquid level metering manifold interface, 2-15, cooling EG liquid inlet, 2-16, cooling EG liquid return, 2-17, cooling EG balance, 2-18, cooling EG drain; 2-2, liquid level metering manifold, 2-21, short pipe, 2-22, liquid level meter connecting pipe, 2-23, liquid level meter connecting pipe, 2-24, docking flange, 2-25, exhaust valve; 2-3, liquid level gauge, 2-4, cooling EG liquid level control valve, 2-5, cooling EG circulation pump, 2-6, filter, G2-7, isolation valve, 2-8, cooling EG tank liquid level balance pipe, 2-81, first valve, 2-82, second valve; 3. Clean EG supply system, 3-1, self-operated regulating valve, G3-2 first isolation valve, G3-3 second isolation valve. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings: Example 1: Reference Figures 1 to 4 As shown, a mechanical seal cooling device comprises: a liquid inlet main pipe 1-2, a liquid return main pipe 1-3 and a balance main pipe 1-4; The mechanical seal flushing and cooling device 1 comprises a liquid inlet manifold 1-5 connected to a liquid inlet main pipe 1-2 and a balance main pipe 1-3, and a liquid return manifold 1-6 connected to a liquid return main pipe 1-3; the liquid inlet manifold 1-5 and the liquid return manifold 1-6 are both provided with two pipe openings, and the two pipe openings on the liquid inlet manifold 1-5 and the liquid return manifold 1-6 are respectively connected to the top end interface and the bottom end interface of the mechanical seal; the four pipe openings are externally connected to valves for controlling the opening and closing of the pipe openings; Cooling EG circulation device 2 and recycling EG; The clean EG supply device 3 supplies clean EG.

[0039] In the present application, a mechanical seal flushing and cooling device 1 is provided, so that the flow direction of EG in the mechanical seal 1-1 can be controlled by respectively controlling the opening and closing of the two pipe openings on the liquid inlet manifold 1-5 and the liquid return manifold 1-6, so that when foreign matter is found, the foreign matter can be flushed out of the mechanical seal 1-1 by switching the flow direction of EG, thereby saving the trouble of stopping the machine for maintenance; by providing a cooling EG circulation device, EG can be cooled and circulated for use, thereby improving the utilization rate of EG; in addition, by providing a clean EG supply device, clean EG can be provided to the mechanical seal 1-1.

[0040] Example 2: Reference Figures 1 to 5 As shown, a mechanical seal cooling device comprises: a liquid inlet main pipe 1-2, a liquid return main pipe 1-3 and a balance main pipe 1-4; The mechanical seal flushing and cooling device 1 comprises a liquid inlet manifold 1-5 connected to a liquid inlet main pipe 1-2 and a balance main pipe 1-3, and a liquid return manifold 1-6 connected to a liquid return main pipe 1-3; the liquid inlet manifold 1-5 and the liquid return manifold 1-6 are both provided with two pipe openings, and the two pipe openings on the liquid inlet manifold 1-5 and the liquid return manifold 1-6 are respectively connected to the top end interface and the bottom end interface of the mechanical seal; the four pipe openings are externally connected to valves for controlling the opening and closing of the pipe openings; Cooling EG circulation device 2 and recycling EG; The clean EG supply device 3 supplies clean EG.

[0041] Specifically, the mechanical seal flushing and cooling device 1 includes the final polymerization mechanical seal 1-1, the liquid inlet main pipe 1-2, the liquid return main pipe 1-3, the balance main pipe 1-4, the liquid inlet header 1-5, the liquid return header 1-6, the liquid inlet flowmeter 1-7 and the liquid return flowmeter 1-8, etc.

[0042] The final polymerization mechanical seal 1-1 is arranged on the stirring shaft of the horizontal final polymerization kettle. A cooling EG interface (bottom interface) is provided at the bottom of the final polymerization mechanical seal 1-1, and a cooling EG interface (top interface) is provided at the top of the final polymerization mechanical seal 1-1. The cooling EG usually flows into the mechanical seal 1-1 from the bottom interface and flows out of the mechanical seal 1-1 from the top interface. The overall flow direction of the cooling EG is bottom-in and top-out.

[0043] The liquid return manifold 1-6 and the liquid inlet manifold 1-5 are provided at a position not less than 600 mm above the top of the final polymerization mechanical seal 1-1.

[0044] The liquid return manifold 1-6 is provided with two pipe openings, specifically, the two pipe openings are respectively the third pipe opening 1-62, the fourth pipe opening 1-61 and the liquid outlet pipe opening 1-63, the liquid outlet pipe opening 1-63 is connected in series with the liquid return flowmeter 1-8, the liquid return flowmeter 1-8 is connected to the liquid return main pipe 1-3 through a process pipeline, the third pipe opening 1-61 is connected in series with the cut-off valve G1-61, and the cut-off valve G1-61 is connected to the cooling EG interface at the bottom of the final mechanical seal 1-1 through a process pipeline. The third pipe opening 1-62 is connected in series with the cut-off valve G1-62, and the cut-off valve G1-62 is connected to the cooling EG interface at the top of the final mechanical seal 1-1 through a process pipeline.

[0045] The liquid inlet manifold 1-5 is provided at the upper part of the liquid return manifold 1-6, and the liquid inlet manifold 1-5 is provided with a liquid inlet pipe port 1-53, a first pipe port 1-51, a second pipe port 1-52 and a pressure balance pipe port 1-54. The front end of the liquid inlet pipe port 1-53 is connected in series with a liquid inlet flowmeter 1-7, and the liquid inlet flowmeter 1-7 is connected to the liquid inlet main pipe 1-2 through a process pipeline, and the pressure balance pipe port 1-54 is connected in series with a cut-off valve G1-54 and then connected to the balance main pipe 1-4 of the cooling EG, the first pipe port 1-51 is connected in series with the cut-off valve G1-51 and then connected to the cooling EG interface at the top of the final mechanical seal 1-1 through a process pipeline, and the second pipe port 1-52 is connected in series with the cut-off valve G1-52 and then connected to the cooling EG interface at the bottom of the final mechanical seal 1-1 through a process pipeline.

[0046] During operation, the isolation valve G1-51 and the isolation valve G1-61 are opened at the same time, and the isolation valve G1-52 and the isolation valve G1-62 are closed at the same time. The flow direction of the mechanical seal 1-1 cooling EG is from top to bottom.

[0047] Open the isolation valve G1-52 and the isolation valve G1-62 at the same time, and close the isolation valve G1-51 and the isolation valve G1-61 at the same time. The flow direction of the mechanical seal 1-1 cooling EG is bottom-in and top-out.

[0048] By adjusting the opening of the isolation valve G1-54 of the liquid inlet manifold 1-5, the flow and pressure of the cooling EG entering the final polymerization mechanical seal 1-1 can be adjusted.

[0049] In the present application, a liquid inlet main pipe 1-2, a liquid return main pipe 1-3 and a balance main pipe 1-4 are provided, so that a plurality of mechanical seals can be connected in parallel, and each mechanical seal can operate independently, thereby improving the utilization efficiency of the overall system.

[0050] Secondly, when in use, the cooling EG flows through the liquid inlet flowmeter 1-7, the liquid inlet manifold 1-5, the mechanical seal 1-1, the liquid return manifold 1-6 and the liquid return flowmeter 1-8 in sequence. It should be noted that the liquid return flowmeter 1-8 and the liquid inlet flowmeter 1-7 in this embodiment are not affected by the flow direction of the cooling EG of the final polymerization mechanical seal 1-1. By comparing and calculating the difference between the liquid inlet flowmeter 1-7 and the liquid return flowmeter 1-8, it can be determined whether the mechanical seal 1-1 has a leakage.

[0051] In addition, once foreign matter enters the sealing cavity or cooling system of the final polymerization mechanical seal 1-1, one-way flushing will block the cooling EG lubrication channel, resulting in cooling EG flow interruption. The flow direction of the cooling EG can be changed by controlling the opening and closing of the first pipe port 1-51, the second pipe port 1-52, the third pipe port 1-62 and the fourth pipe port 1-63, so that the mechanical seal 1-1 can be flushed to flush out the foreign matter, thereby restoring the sealing function of the mechanical seal 1-1 and extending the service life of the mechanical seal 1-1 without stopping for maintenance.

[0052] Finally, by adjusting the opening of the isolation valve G1-54 of the pressure balance pipe port 1-54 of the liquid inlet manifold 1-5, the cooling EG flow and pressure entering the final polymerization mechanical seal 1-1 can be adjusted to maintain a lower cooling EG pressure inside the mechanical seal 1-1, which is beneficial to reduce the leakage of the mechanical seal 1-1 and extend the service life of the mechanical seal 1-1.

[0053] The cooling EG circulation device 2 includes a cooling EG storage tank 2-1; the top of the cooling EG storage tank 2-1 is connected to the cleaning EG supply device 3; a cooling device is arranged inside the cooling EG storage tank 2-1, and the cooling device is used to cool the EG inside the cooling EG storage tank 2-1; the side wall of the cooling EG storage tank 2-1 is provided with a cooling EG liquid return pipe port 2-16, a cooling EG balance pipe port 2-17 and a cooling EG liquid inlet pipe port 2-15; the cooling EG liquid inlet pipe port 2-15 is connected to the liquid inlet main pipe 1-2, the cooling EG liquid return pipe port 2-16 is connected to the liquid return main pipe 1-3, and the cooling EG balance pipe port 2-17 is connected to the balance main pipe 1-4.

[0054] The cooling EG circulation device 2 also includes a liquid level metering header 2-2, a liquid level meter 2-3, a cooling EG liquid level control valve 2-4, a cooling EG circulation pump 2-5, a filter 2-6, a cut-off valve G2-7 and process pipelines.

[0055] The cooling EG storage tank 2-1 is a vertical barrel container with a conical bottom and a flat top. The top of the cooling EG storage tank 2-1 is provided with the clean EG inlet 2-13 and the liquid level metering header interface 2-14. The liquid level metering header interface 2-14 is connected to the cooling EG storage tank 2-1 through a docking flange 2-24. The clean EG inlet 2-13 is externally connected to the cooling EG liquid level control valve 2-4. The liquid level metering header interface 2-14 is connected to the liquid level metering header 2-2 on top. The liquid level metering header 2-2 is a small diameter The short tube 2-21 is vertically arranged, and the top of the short tube 2-21 is provided with an exhaust valve 2-25. The upper end of the short tube 2-21 is provided with the liquid level gauge pipe opening 2-23, and the lower end of the short tube 2-21 is provided with the liquid level gauge pipe opening 2-22. The liquid level gauge pipe 2-22 and the liquid level gauge pipe 2-23 are externally connected to the liquid level gauge 2-3. The liquid level gauge 2-3 maintains the cooling EG in the liquid level metering header 2-2 within a certain height range by switching the cooling EG liquid level control valve 2-4. The liquid level metering header 2-2 is sensitive to the change of the total amount of circulating cooling EG, so it is easy to determine whether the mechanical seal 1-1 is leaking.

[0056] The cooling device is provided inside the cooling EG storage tank 2-1, the cooling EG liquid inlet pipe 2-15 is provided at the lower part of the cylindrical body 2-11 of the cooling EG storage tank 2-1, and the cooling EG liquid return pipe 2-16 and the cooling EG balance pipe 2-17 are provided at the upper part of the cylindrical body 2-11. That is, the cooling EG liquid inlet pipe 2-15 is provided at one end of the side wall of the cooling EG storage tank close to the bottom. After the EG flows in from the cooling EG liquid return pipe 2-16, the temperature is relatively high, and then the relatively high temperature EG liquid is gradually cooled from the upper part to the lower end of the EG storage tank 2-1, and then the EG can be fully cooled in the cooling EG storage tank 2-1 and then flow out from the cooling EG liquid inlet pipe 2-15.

[0057] The bottom of the cooling EG storage tank 2-1 is in the shape of a trumpet with a gradually increasing opening. The bottom of the cooling EG storage tank 2-1 in this embodiment is conical. The cooling EG storage tank 2-1 is provided with the cooling EG drain port 2-18 at the bottom. The cooling EG drain port 2-18 is connected in parallel with the cooling EG storage tank liquid level balance pipe 2-8. The top height of the cooling EG storage tank liquid level balance pipe 2-8 is between the liquid level gauge pipe port 2-22 and the liquid level gauge pipe port 2-23. The outlet of the cooling EG storage tank liquid level balance pipe 2-8 is connected to the final heat well through a process pipeline. Two process pipelines arranged in parallel are arranged between the cooling EG drain port 2-18 and the final heat well. The first valve 2-81 and the second valve 2-82 are respectively arranged on the two parallel process pipelines. During normal operation, the first valve 2-81 is opened and the second valve 2-82 is closed. When the system EG is replaced or shut down for draining, the second valve 2-82 is opened and the first valve 2-81 is opened or closed.

[0058] The cooling EG liquid inlet pipe 2-15 is connected in series with the cooling EG circulating pump 2-5, the filter 2-6 and the isolation valve G2-7 through a process pipeline, and finally connected to the liquid inlet main pipe 1-2 through a process pipeline. The cooling EG circulating pump 2-5 and the filter 2-6 are combined to form a circulating filtering device, thereby filtering EG. In addition, the circulating filtering device in this embodiment is arranged in two groups, that is, two groups of cooling EG circulating pumps 2-5 and filters 2-6 are arranged in parallel, one group is for normal use, and the other group is for standby use.

[0059] The cooling EG liquid return pipe port 2-16 is connected to the liquid return main pipe 1-3.

[0060] The cooling EG balance pipe port 2-17 is connected to the balance main pipe 1-4 through a process pipeline.

[0061] The clean EG supply system 3 includes a self-operated regulating valve 3-1, a first isolating valve G3-2 and a second isolating valve G3-3, etc. The self-operated regulating valve 3-1 is connected to the clean EG pipeline from the delivery pump, and the outlet of the self-operated regulating valve is divided into two paths, one path flows through the first isolating valve G3-2 and enters the liquid inlet main pipe 1-2, and the other path flows through the second isolating valve G3-3 and enters the cooling EG liquid level control valve 2-4.

[0062] The working principle of the present application is: clean EG directly cools the mechanical seal: open the first isolating valve G3-2, and close the second isolating valve G3-3 and the isolating valve G2-7 at the same time, and the clean EG of 0.2MPa flows through the liquid inlet main pipe 1-2, the liquid inlet flowmeter 1-7, the liquid inlet manifold 1-5, the mechanical seal 1-1, the liquid return manifold 1-6, the liquid return flowmeter 1-8, the liquid return main pipe 1-3, the cooling EG storage tank 2-1 and the cooling EG storage tank liquid level balance pipe 2-8, and finally discharged into the final heat collection well.

[0063] Clean EG indirect cooling mechanical seal: open the second isolation valve 3-3 and isolation valve G2-7, and close the first isolation valve G3-2 at the same time. The clean EG at 0.2MPa flows through the cooling EG level control valve 2-4 into the cooling EG storage tank 2-1. The cooled EG enters the cooling EG circulation pump 2-5. The cooled EG flows through the filter 2-6, isolation valve G2-7, the liquid inlet main pipe 1-2, the liquid inlet flowmeter 1-7, the liquid inlet manifold 1-5, the mechanical seal 1-1, the liquid return manifold 1-6, the liquid return flowmeter 1-8 and the liquid return main pipe 1-3 in sequence, and flows into the cooling EG storage tank 2-1 again. After cooling, the cooled EG is recycled.

[0064] Example 3: Reference Figures 1 to 5 As shown, a mechanical seal cooling device comprises: a liquid inlet main pipe 1-2, a liquid return main pipe 1-3 and a balance main pipe 1-4; The mechanical seal flushing and cooling device 1 comprises a liquid inlet manifold 1-5 connected to a liquid inlet main pipe 1-2 and a balance main pipe 1-3, and a liquid return manifold 1-6 connected to a liquid return main pipe 1-3; the liquid inlet manifold 1-5 and the liquid return manifold 1-6 are both provided with two pipe openings, and the two pipe openings on the liquid inlet manifold 1-5 and the liquid return manifold 1-6 are respectively connected to the top end interface and the bottom end interface of the mechanical seal; the four pipe openings are externally connected to valves for controlling the opening and closing of the pipe openings; Cooling EG circulation device 2 and recycling EG; The clean EG supply device 3 supplies clean EG.

[0065] Specifically, the mechanical seal flushing and cooling device 1 includes the final polymerization mechanical seal 1-1, the liquid inlet main pipe 1-2, the liquid return main pipe 1-3, the balance main pipe 1-4, the liquid inlet header 1-5, the liquid return header 1-6, the liquid inlet flowmeter 1-7 and the liquid return flowmeter 1-8, etc.

[0066] The final polymerization mechanical seal 1-1 is arranged on the stirring shaft of the horizontal final polymerization kettle. A cooling EG interface (bottom interface) is provided at the bottom of the final polymerization mechanical seal 1-1, and a cooling EG interface (top interface) is provided at the top of the final polymerization mechanical seal 1-1. The cooling EG usually flows into the mechanical seal 1-1 from the bottom interface and flows out of the mechanical seal 1-1 from the top interface. The overall flow direction of the cooling EG is bottom-in and top-out.

[0067] The liquid return manifold 1-6 and the liquid inlet manifold 1-5 are provided at a position not less than 600 mm above the top of the final polymerization mechanical seal 1-1.

[0068] The liquid return manifold 1-6 is provided with two pipe openings, specifically, the two pipe openings are respectively the third pipe opening 1-62, the fourth pipe opening 1-61 and the liquid outlet pipe opening 1-63, the liquid outlet pipe opening 1-63 is connected in series with the liquid return flowmeter 1-8, the liquid return flowmeter 1-8 is connected to the liquid return main pipe 1-3 through a process pipeline, the third pipe opening 1-61 is connected in series with the cut-off valve G1-61, and the cut-off valve G1-61 is connected to the cooling EG interface at the bottom of the final mechanical seal 1-1 through a process pipeline. The third pipe opening 1-62 is connected in series with the cut-off valve G1-62, and the cut-off valve G1-62 is connected to the cooling EG interface at the top of the final mechanical seal 1-1 through a process pipeline.

[0069] The liquid inlet manifold 1-5 is provided at the upper part of the liquid return manifold 1-6, and the liquid inlet manifold 1-5 is provided with a liquid inlet pipe port 1-53, a first pipe port 1-51, a second pipe port 1-52 and a pressure balance pipe port 1-54. The front end of the liquid inlet pipe port 1-53 is connected in series with a liquid inlet flowmeter 1-7, and the liquid inlet flowmeter 1-7 is connected to the liquid inlet main pipe 1-2 through a process pipeline, and the pressure balance pipe port 1-54 is connected in series with a cut-off valve G1-54 and then connected to the balance main pipe 1-4 of the cooling EG, the first pipe port 1-51 is connected in series with the cut-off valve G1-51 and then connected to the cooling EG interface at the top of the final mechanical seal 1-1 through a process pipeline, and the second pipe port 1-52 is connected in series with the cut-off valve G1-52 and then connected to the cooling EG interface at the bottom of the final mechanical seal 1-1 through a process pipeline.

[0070] During operation, the isolation valve G1-51 and the isolation valve G1-61 are opened at the same time, and the isolation valve G1-52 and the isolation valve G1-62 are closed at the same time. The flow direction of the mechanical seal 1-1 cooling EG is from top to bottom.

[0071] Open the isolation valve G1-52 and the isolation valve G1-62 at the same time, and close the isolation valve G1-51 and the isolation valve G1-61 at the same time. The flow direction of the mechanical seal 1-1 cooling EG is bottom-in and top-out.

[0072] By adjusting the opening of the isolation valve G1-54 of the liquid inlet manifold 1-5, the flow and pressure of the cooling EG entering the final polymerization mechanical seal 1-1 can be adjusted.

[0073] In the present application, a liquid inlet main pipe 1-2, a liquid return main pipe 1-3 and a balance main pipe 1-4 are provided, so that a plurality of mechanical seals can be connected in parallel, and each mechanical seal can operate independently, thereby improving the utilization efficiency of the overall system.

[0074] Secondly, when in use, the cooling EG flows through the liquid inlet flowmeter 1-7, the liquid inlet manifold 1-5, the mechanical seal 1-1, the liquid return manifold 1-6 and the liquid return flowmeter 1-8 in sequence. It should be noted that the liquid return flowmeter 1-8 and the liquid inlet flowmeter 1-7 in this embodiment are not affected by the flow direction of the cooling EG of the final polymerization mechanical seal 1-1. By comparing and calculating the difference between the liquid inlet flowmeter 1-7 and the liquid return flowmeter 1-8, it can be determined whether the mechanical seal 1-1 has a leakage.

[0075] In addition, once foreign matter enters the sealing cavity or cooling system of the final polymerization mechanical seal 1-1, one-way flushing will block the cooling EG lubrication channel, resulting in cooling EG flow interruption. The flow direction of the cooling EG can be changed by controlling the opening and closing of the first pipe port 1-51, the second pipe port 1-52, the third pipe port 1-62 and the fourth pipe port 1-63, so that the mechanical seal 1-1 can be flushed to flush out the foreign matter, thereby restoring the sealing function of the mechanical seal 1-1 and extending the service life of the mechanical seal 1-1 without stopping for maintenance.

[0076] Finally, by adjusting the opening of the isolation valve G1-54 of the pressure balance pipe port 1-54 of the liquid inlet manifold 1-5, the cooling EG flow and pressure entering the final polymerization mechanical seal 1-1 can be adjusted to maintain a lower cooling EG pressure inside the mechanical seal 1-1, which is beneficial to reduce the leakage of the mechanical seal 1-1 and extend the service life of the mechanical seal 1-1.

[0077] The cooling EG circulation device 2 includes a cooling EG storage tank 2-1; the top of the cooling EG storage tank 2-1 is connected to the cleaning EG supply device 3; a cooling device is arranged inside the cooling EG storage tank 2-1, and the cooling device is used to cool the EG inside the cooling EG storage tank 2-1; the side wall of the cooling EG storage tank 2-1 is provided with a cooling EG liquid return pipe port 2-16, a cooling EG balance pipe port 2-17 and a cooling EG liquid inlet pipe port 2-15; the cooling EG liquid inlet pipe port 2-15 is connected to the liquid inlet main pipe 1-2, the cooling EG liquid return pipe port 2-16 is connected to the liquid return main pipe 1-3, and the cooling EG balance pipe port 2-17 is connected to the balance main pipe 1-4.

[0078] The cooling EG circulation device 2 also includes a liquid level metering header 2-2, a liquid level meter 2-3, a cooling EG liquid level control valve 2-4, a cooling EG circulation pump 2-5, a filter 2-6, a cut-off valve G2-7 and process pipelines.

[0079] The cooling EG storage tank 2-1 is a vertical barrel container with a conical bottom and a flat top. The top of the cooling EG storage tank 2-1 is provided with the clean EG inlet 2-13 and the liquid level metering header interface 2-14. The liquid level metering header interface 2-14 is connected to the cooling EG storage tank 2-1 through a docking flange 2-24. The clean EG inlet 2-13 is externally connected to the cooling EG liquid level control valve 2-4. The liquid level metering header interface 2-14 is connected to the liquid level metering header 2-2 on top. The liquid level metering header 2-2 is a small diameter The short tube 2-21 is vertically arranged, and the top of the short tube 2-21 is provided with an exhaust valve 2-25. The upper end of the short tube 2-21 is provided with the liquid level gauge pipe opening 2-23, and the lower end of the short tube 2-21 is provided with the liquid level gauge pipe opening 2-22. The liquid level gauge pipe 2-22 and the liquid level gauge pipe 2-23 are externally connected to the liquid level gauge 2-3. The liquid level gauge 2-3 maintains the cooling EG in the liquid level metering header 2-2 within a certain height range by switching the cooling EG liquid level control valve 2-4. The liquid level metering header 2-2 is sensitive to the change of the total amount of circulating cooling EG, so it is easy to determine whether the mechanical seal 1-1 is leaking.

[0080] The cooling device is provided inside the cooling EG storage tank 2-1, the cooling EG liquid inlet pipe 2-15 is provided at the lower part of the cylindrical body 2-11 of the cooling EG storage tank 2-1, and the cooling EG liquid return pipe 2-16 and the cooling EG balance pipe 2-17 are provided at the upper part of the cylindrical body 2-11. That is, the cooling EG liquid inlet pipe 2-15 is provided at one end of the side wall of the cooling EG storage tank close to the bottom. After the EG flows in from the cooling EG liquid return pipe 2-16, the temperature is relatively high, and then the relatively high temperature EG liquid is gradually cooled from the upper part to the lower end of the EG storage tank 2-1, and then the EG can be fully cooled in the cooling EG storage tank 2-1 and then flow out from the cooling EG liquid inlet pipe 2-15.

[0081] The bottom of the cooling EG storage tank 2-1 is in the shape of a trumpet with a gradually increasing opening. The bottom of the cooling EG storage tank 2-1 in this embodiment is conical. The cooling EG storage tank 2-1 is provided with the cooling EG drain port 2-18 at the bottom. The cooling EG drain port 2-18 is connected in parallel with the cooling EG storage tank liquid level balance pipe 2-8. The top height of the cooling EG storage tank liquid level balance pipe 2-8 is between the liquid level gauge pipe port 2-22 and the liquid level gauge pipe port 2-23. The outlet of the cooling EG storage tank liquid level balance pipe 2-8 is connected to the final heat well through a process pipeline. Two process pipelines arranged in parallel are arranged between the cooling EG drain port 2-18 and the final heat well. The first valve 2-81 and the second valve 2-82 are respectively arranged on the two parallel process pipelines. During normal operation, the first valve 2-81 is opened and the second valve 2-82 is closed. When the system EG is replaced or shut down for draining, the second valve 2-82 is opened and the first valve 2-81 is opened or closed.

[0082] The cooling EG liquid inlet pipe 2-15 is connected in series with the cooling EG circulating pump 2-5, the filter 2-6 and the isolation valve G2-7 through a process pipeline, and finally connected to the liquid inlet main pipe 1-2 through a process pipeline. The cooling EG circulating pump 2-5 and the filter 2-6 are combined to form a circulating filtering device, thereby filtering EG. In addition, the circulating filtering device in this embodiment is arranged in two groups, that is, two groups of cooling EG circulating pumps 2-5 and filters 2-6 are arranged in parallel, one group is for normal use, and the other group is for standby use.

[0083] The cooling EG liquid return pipe port 2-16 is connected to the liquid return main pipe 1-3.

[0084] The cooling EG balance pipe port 2-17 is connected to the balance main pipe 1-4 through a process pipeline.

[0085] The clean EG supply system 3 includes a self-operated regulating valve 3-1, a first isolating valve G3-2 and a second isolating valve G3-3, etc. The self-operated regulating valve 3-1 is connected to the clean EG pipeline from the delivery pump, and the outlet of the self-operated regulating valve is divided into two paths, one path flows through the first isolating valve G3-2 and enters the liquid inlet main pipe 1-2, and the other path flows through the second isolating valve G3-3 and enters the cooling EG liquid level control valve 2-4.

[0086] This embodiment is similar in structure to embodiment 2, except that the cooling device includes a spiral cooling coil 2-12, and a cooling coil inlet 2-12-1 and a cooling coil outlet 2-12-2 are respectively provided at both ends of the cooling coil 2-12. The axis of the spiral cooling coil is arranged parallel to the axis direction of the cooling EG tank 2-1. After the cooling medium enters the cooling coil from the cooling coil inlet 2-12-1, it flows out of the cooling coil 2-12 from the cooling coil outlet 2-12-2 to cool the inside of the cooling EG tank 2-1. The spiral cooling coil can improve the cooling efficiency of the EG.

[0087] The working principle of the present application is: clean EG directly cools the mechanical seal: open the first isolating valve G3-2, and close the second isolating valve G3-3 and the isolating valve G2-7 at the same time, and the clean EG of 0.2MPa flows through the liquid inlet main pipe 1-2, the liquid inlet flowmeter 1-7, the liquid inlet manifold 1-5, the mechanical seal 1-1, the liquid return manifold 1-6, the liquid return flowmeter 1-8, the liquid return main pipe 1-3, the cooling EG storage tank 2-1 and the cooling EG storage tank liquid level balance pipe 2-8, and finally discharged into the final heat collection well.

[0088] Clean EG indirect cooling mechanical seal: open the second isolation valve 3-3 and isolation valve G2-7, and close the first isolation valve G3-2 at the same time. The clean EG at 0.2MPa flows through the cooling EG level control valve 2-4 into the cooling EG storage tank 2-1. The cooled EG enters the cooling EG circulation pump 2-5. The cooled EG flows through the filter 2-6, isolation valve G2-7, the liquid inlet main pipe 1-2, the liquid inlet flowmeter 1-7, the liquid inlet manifold 1-5, the mechanical seal 1-1, the liquid return manifold 1-6, the liquid return flowmeter 1-8 and the liquid return main pipe 1-3 in sequence, and flows into the cooling EG storage tank 2-1 again. After cooling, the cooled EG is recycled.

[0089] The above-described embodiments are only preferred solutions of the present invention and are not intended to limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solutions described in the claims.

Claims

1. A mechanical seal cooling device, characterized in that: include: Liquid inlet main pipe, liquid return main pipe and balance main pipe; The mechanical seal flushing and cooling device comprises a liquid inlet manifold and a liquid return manifold, wherein the liquid inlet manifold is connected to a liquid inlet main pipe and a balance main pipe, and the liquid return manifold is connected to a liquid return main pipe; the liquid inlet manifold and the liquid return manifold are both provided with two pipe openings, and the two pipe openings on the liquid inlet manifold and the liquid return manifold are respectively connected to a top end interface and a bottom end interface of the mechanical seal; and the plurality of pipe openings are externally connected to valves for controlling the opening and closing of the pipe openings; Cooling EG circulation device and recycling EG; The clean EG supply device provides clean EG.

2. The mechanical seal cooling device according to claim 1 is characterized in that: The inlet of the liquid inlet manifold is provided with a liquid inlet flow meter for detecting the liquid inlet flow rate, and the outlet of the liquid return manifold is provided with a liquid return flow meter for detecting the liquid return flow rate.

3. The mechanical seal cooling device according to claim 1 is characterized in that: The two pipe openings of the liquid inlet manifold are respectively a first pipe opening and a second pipe opening; the first pipe opening is connected to the top end interface, and the second pipe opening is connected to the bottom end interface; The two pipe openings of the liquid return manifold are respectively the third pipe opening and the fourth pipe opening; the third pipe opening is communicated with the top end interface, and the fourth pipe opening is communicated with the bottom end interface.

4. The mechanical seal cooling device according to claim 1 is characterized in that the cooling The EG circulation device includes a cooling EG storage tank; The top of the cooling EG storage tank is connected to the clean EG supply device; A cooling device is provided inside the cooling EG tank; The side wall of the cooling EG storage tank is provided with a cooling EG liquid return pipe port, a cooling EG balance pipe port and a cooling EG liquid inlet pipe port; the cooling EG liquid inlet pipe port is connected to the liquid inlet main pipe, the cooling EG liquid return pipe port is connected to the liquid return main pipe, and the cooling EG balance pipe port is connected to the balance main pipe.

5. The mechanical seal cooling device according to claim 4 is characterized in that: The cooling EG liquid inlet pipe port is arranged at one end of the side wall of the cooling EG storage tank close to the bottom.

6. The mechanical seal cooling device according to claim 4 or 5, characterized in that: A circulation filter device is provided between the cooling EG liquid inlet pipe port and the liquid inlet main pipe; the cooling EG flows out of the cooling EG storage tank, passes through the circulation filter device and then flows into the liquid inlet main pipe.

7. The mechanical seal cooling device according to claim 4, characterized in that: The cooling device comprises a spiral cooling coil, and a cooling coil inlet and a cooling coil outlet are respectively arranged at two ends of the cooling coil.

8. The mechanical seal cooling device according to claim 4, 5 or 7, characterized in that: The bottom of the cooling EG storage tank is in a trumpet shape with gradually increasing openings, and a cooling EG drain port is provided at the bottom of the cooling EG storage tank.

9. The mechanical seal cooling device according to any one of claims 1 to 5, characterized in that: The clean EG supply device includes a self-operated regulating valve and a delivery pump. The outlet of the self-operated regulating valve is divided into two routes, which are respectively connected to the liquid inlet main pipe and the cooling EG storage tank.

10. The mechanical seal cooling device according to claim 4, 5 or 7, characterized in that: A liquid level metering header and a liquid level gauge are provided on the top of the cooling EG tank.

Images