Three-stage vacuum system for extruder

Abstract

The three-stage vacuum system comprises a vacuum unit, an oil-gas separation unit and a water circulation unit, wherein the vacuum unit is provided with a second-stage vacuum pump, a first-stage vacuum pump and a water ring pump; the oil-gas separation unit is connected between an exhaust port of the extruder and the vacuum unit; the water circulation unit is communicated with the water ring pump; the oil-gas separation unit comprises a first air cooling tank, a dirt collecting tank, an air filtering tank and a second air cooling tank which are sequentially communicated in one direction, the first air cooling tank is communicated with the exhaust port, and the second air cooling tank is communicated with the secondary vacuum pump; the condenser is communicated between the water storage tank and the water ring pump so as to cool working water conveyed to the water ring pump by the water storage tank, and the water ring pump is communicated with fluid of the water storage tank; the suction efficiency is improved through the three vacuum pumps, impurities in gas are completely removed through secondary cooling and secondary filtering, the cooling effect is improved, the vacuum pumps and the water ring pump are protected, and the working performance of the water ring pump is guaranteed.

Description

Technical Field

[0001] This application relates to the technical field of plastic production equipment, and in particular to a three-stage vacuum system for an extruder. Background Art

[0002] During the production of PET, if the gas in the main machine is not pumped out, bubbles and impurities will appear on the surface of the produced products, thus affecting the quality and transparency of the PET sheet; due to the improvement of the production capacity of the current flat twin main machine, the total amount and temperature of the gas generated by the high-output flat twin main machine become more. In order to meet the increased production demand, a vacuum system with a large pumping force and better cooling effect is required. Summary of the Invention

[0003] In order to solve the above technical problems, the purpose of this application is to provide a three-stage vacuum system for an extruder.

[0004] To achieve the above object, this application adopts the following technical solution: A three-stage vacuum system for an extruder is arranged on one side of the extruder and communicated with the exhaust port of the extruder. The three-stage vacuum system includes: A vacuum unit, including a two-stage vacuum pump, a one-stage vacuum pump and a water ring pump that are connected in series in sequence; An oil-gas separation unit is connected between the exhaust port and the vacuum unit. The oil-gas separation unit includes a first air cooling tank, a dirt collection tank, an air filter tank and a second air cooling tank that are connected in series in sequence. The inlet of the first air cooling tank is communicated with the exhaust port, the outlet of the second air cooling tank is communicated with the two-stage vacuum pump, and a plurality of filtering components are arranged between the inlet and the outlet of the air filter tank. The first air cooling tank and the second air cooling tank are used to reduce the temperature of the air; and A water circulation unit, including a water storage tank for storing working water and a condenser for cooling the working water. The water storage tank has a total water inlet communicated with the total water source and a total air outlet for discharging gas from the three-stage vacuum system. Between the water storage tank and the water ring pump, there are independent water inlet path, water outlet path and exhaust path. The condenser is arranged in the water inlet path. The water inlet path is configured to supply the working water to the water ring pump unidirectionally from the water storage tank. The water outlet path is configured to supply the working water to the water storage tank unidirectionally from the water ring pump. The exhaust path is configured to supply the gas to the total air outlet unidirectionally from the water ring pump.

[0005] In the above technical solution, further preferably, the dirt collection tank is arranged below the first air cooling tank and the air filter tank.

[0006] In the above technical solution, further preferably, the air inlet and the air outlet of the sewage collection tank are both located at the top of the sewage collection tank and are far away from each other; the air inlet of the sewage collection tank is communicated with the air outlet of the first air cooling tank, and the air outlet of the sewage collection tank is communicated with the air inlet of the air filtration tank.

[0007] In the above technical solution, further preferably, the vacuum unit is communicated with the oil-gas separation unit through a pipeline, and a pneumatic butterfly valve is arranged in the pipeline.

[0008] In the above technical solution, further preferably, both the secondary vacuum pump and the primary vacuum pump are roots pumps.

[0009] In the above technical solution, further preferably, the total air outlet of the water storage tank is located at the top of the water storage tank.

[0010] In the above technical solution, further preferably, the water storage tank is also provided with an overflow port, and the overflow port is located in the upper half of the water storage tank and below the total air outlet of the water storage tank.

[0011] In the above technical solution, further preferably, a liquid level gauge is arranged on the water storage tank.

[0012] In the above technical solution, further preferably, the condenser includes an internal circulation passage for conveying the working water and an external circulation passage for conveying the cooling water. The internal circulation passage communicates the water storage tank and the water ring pump, and the external circulation passage communicates with an external cooling source. The internal circulation passage and the external circulation passage are independently arranged.

[0013] The present application has the following beneficial effects compared with the prior art: The present application sucks the exhaust port of the extruder through two series-connected vacuum pumps and a water ring pump to improve the suction efficiency; the oil-gas separation unit performs secondary cooling and secondary filtration on the gas sucked from the exhaust port to the vacuum unit, completely removes impurities in the gas and reduces the temperature of the gas, improves the cooling effect, protects the roots pump and the water ring pump, extends the service life of the equipment, and can be applicable to different production environments; the water circulation unit cools the working water ring pump and discharges the gas sucked by the water ring pump to the external environment to ensure the working performance of the water ring pump. Description of the Drawings

[0014] Figure 1 is the front view of a three-stage vacuum system for an extruder provided by an embodiment of the present application; Figure 2 isFigure 1 Side view of the three - stage vacuum system in Figure 3 Schematic diagram of the path for gas transportation in Figure 1 the three - stage vacuum system shown; Figure 4 Schematic diagram of the path for working water transportation in Figure 1 the three - stage vacuum system shown.

[0015] Wherein: 100, three - stage vacuum system; 10, vacuum unit; 1, secondary vacuum pump; 2, primary vacuum pump; 3, water - ring pump; 31, first water inlet; 32, first water outlet; 33, inlet; 34, outlet; 20, oil - gas separation unit; 4, first air cooling tank; 41, first air inlet; 42, first air outlet; 5, sewage collection tank; 51, second air inlet; 52, second air outlet; 6, air filter tank; 61, third air inlet; 62, third air outlet; 63, filtering component; 7, second air cooling tank; 71, fourth air inlet; 72, fourth air outlet; 11, pneumatic butterfly valve; 30, water circulation unit; 8, water storage tank; 81, total water inlet; 82, small air inlet; 83, second water inlet; 84, second water outlet; 85, total air outlet; 86, tank body; 9, condenser; 91, internal circulation path; 911, third water inlet; 912, third water outlet; 92, external circulation path. Detailed implementation mode

[0016] To describe in detail the technical content, structural features, achieved objectives and effects of the application, the technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. In the following description, for the purpose of explanation, many specific details are set forth to provide a detailed description of various exemplary embodiments or implementations of the invention. However, various exemplary embodiments can also be implemented without these specific details or in the case of one or more equivalent arrangements. In addition, various exemplary embodiments can be different, but not necessarily exclusive. For example, without departing from the inventive concept, the specific shapes, structures and characteristics of an exemplary embodiment can be used or implemented in another exemplary embodiment.

[0017] Hereinafter, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0018] In this application, unless otherwise clearly specified and defined, the term "connection" shall be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral one; it can be directly connected or indirectly connected through an intermediate medium.

[0019] The "upper" and "lower" described in this application are in accordance with the Figure 1 upper and lower shown.

[0020] An embodiment of this application provides a three-stage vacuum system for an extruder. The three-stage vacuum system 100 is arranged on one side of the extruder and is communicated with the exhaust port of the extruder to extract the gas containing impurities and heat in the extruder, reducing the gas and impurity content in the material produced by the extruder.

[0021] As Figure 1 shown, the three-stage vacuum system 100 includes a vacuum unit 10 for loading a suction negative pressure at the exhaust port, an oil-gas separation unit 20 for cooling and filtering the gas discharged from the exhaust port, and a water circulation unit 30 for discharging the gas and cooling at least part of the vacuum unit 10.

[0022] The vacuum unit 10 includes a secondary vacuum pump 1, a primary vacuum pump 2, and a water ring pump 3. The secondary vacuum pump 1, the primary vacuum pump 2, and the water ring pump 3 are connected in sequence and form a one-way gas transmission channel. In the embodiment of this application, both the secondary vacuum pump 1 and the primary vacuum pump 2 are roots pumps; the secondary vacuum pump 1 uses a roots pump with a power of 7.5KW, the primary vacuum pump 2 uses a roots pump with a power of 4KW, and the water ring pump 3 uses a water ring pump with a power of 15KW. By connecting three vacuum pumps in series, the suction flow rate and velocity of the three-stage vacuum system 100 are increased, thereby improving the suction efficiency, making the material of the extruder free of excess gas and impurities, and improving the quality and transparency of the product. On the other hand, the series connection of the roots pump and the water ring pump ensures the continuity of the suction flow rate, making each vacuum pump in the best working state. In other embodiments, roots pumps and water ring pumps with other powers can be used in combination to be applicable to different product production lines.

[0023] During the working process, first start the water ring pump 3, then start the primary vacuum pump 2, and finally start the secondary vacuum pump 1. The water ring pump 3 is connected to the water circulation unit 30 to discharge the sucked gas through the water circulation unit 30, so it is necessary to start the water ring pump 3 first for work.

[0024] As Figure 1 、 2As shown, the oil-gas separation unit 20 is connected between the exhaust port and the vacuum unit 10. The oil-gas separation unit 20 includes a first air cooling tank 4, a sewage collection tank 5, an air filtration tank 6, and a second air cooling tank 7 that are connected in sequence. The first air cooling tank 4, the sewage collection tank 5, the air filtration tank 6, and the second air cooling tank 7 form a one-way filtration channel for cooling and filtering the gas output from the exhaust port. The three vacuum pumps of the vacuum unit 10 generate negative pressure at the exhaust port and inside the one-way filtration channel, so that the gas discharged from the exhaust port is sucked into the vacuum unit 10 through the one-way filtration channel.

[0025] As Figure 1 , 3 shown, the first air cooling tank 4 includes a first air inlet 41 communicating with the exhaust port and a first air outlet 42 communicating with the sewage collection tank 5. The gas output from the exhaust port is preliminarily cooled in the first air cooling pipe 4, so that the impurities in the gas are cooled and condensed.

[0026] The top of the sewage collection tank 5 is provided with a second air inlet 51 and a second air outlet 52. The second air inlet 51 and the second air outlet 52 are far away from each other and do not affect each other. The second air inlet 51 is communicated with the first air outlet 42, and the second air outlet 52 is communicated with the sewage collection tank 5. The gas cooled by the first air cooling tank 4 enters the tank body of the sewage collection tank 5 from the second air inlet 51, so that the condensed impurities in the gas are deposited at the bottom of the sewage collection tank 5, and the gas floats on the upper half of the sewage collection tank 5 and enters the air filtration tank 6 from the second air outlet 52 under the suction of the vacuum unit 10.

[0027] The air filtration tank 6 includes a third air inlet 61 and a third air outlet 62 that are far away from each other, and a plurality of filtering components 63 are arranged between the third air inlet 61 and the third air outlet 62; the third air inlet 61 is communicated with the second air outlet 52, and the third air outlet 62 is communicated with the second air cooling tank 7; the gas separated by the sewage collection tank 5 enters the air filtration pipe 6 from the third air inlet 61. Under the suction of the vacuum unit 10, after the gas passes through the multiple filtering components 63 for re-filtration, the impurities in the gas are completely removed, and the gas with impurities removed enters the second air cooling tank 7 from the third air outlet 62. In the embodiment of the present application, the filtering component 63 is a filter screen, and the filter screen can block the impurities in the gas and allow the filtered gas to pass through.

[0028] Since the density of the condensed impurities is greater than the density of the gas, the sewage collection tank 5 is arranged below the first air cooling tank 4 and the air filtration tank 6, so that the impurities can sink to the bottom of the tank body, the gas floats above the impurities, and the floating gas enters the upper air filtration tank 6 from the second air outlet 52 at the top, effectively avoiding the deposited impurities from being brought into the air filtration tank 6 and realizing preliminary oil-gas separation.

[0029] The second air cooling tank 7 includes a fourth air inlet 71 and a fourth air outlet 72. The fourth air inlet 71 communicates with the third air outlet 62, and the fourth air outlet 72 is connected to the air inlet of the secondary vacuum pump 1. The second air cooling tank 7 performs secondary cooling on the gas with impurities removed, improving the cooling effect, reducing the temperature of the gas transported to the vacuum unit 10 to a level that does not affect the performance and operation of the three vacuum pumps, avoiding the influence of the high temperature of the gas on the performance and service life of the vacuum pumps, and enhancing the stability of the operation of this three-stage vacuum system.

[0030] The oil-gas separation unit 20 performs secondary filtration and secondary cooling on the gas output from the exhaust port, completely removing impurities in the gas and reducing the temperature of the gas, protecting the roots pump and the water ring pump, avoiding the influence of impurities and high temperature in the gas on the roots pump and the water ring pump, and extending the service life.

[0031] A pipeline is connected between the air inlet of the secondary vacuum pump 1 and the fourth air outlet 72 of the second air cooling tank 7, and a pneumatic butterfly valve 11 is arranged in the pipeline. The pneumatic butterfly valve 11 is opened and closed under the control of an external control system.

[0032] The water circulation unit 30 is connected to the water ring pump 3 of the vacuum unit 10, used to cool down the water ring pump 3 to reduce the temperature that rises during the suction process of the water ring pump 3, and discharge the gas sucked by the water ring pump 3 to the external environment. The water ring pump 3 includes a first water inlet 31 for inputting working water, a first water outlet 32 for outputting working water, an inlet 33 for inputting gas, and an outlet 34 for outputting gas. The inlet 33 is connected to the primary vacuum pump 2 to suck the gas from the exhaust port into the vacuum unit 10; the first water outlet 32, the first water inlet 31, and the outlet 34 are all connected to the water circulation unit 30.

[0033] As Figure 1 、 4 shown, the water circulation unit 30 includes a water storage tank 8 and a condenser 9. The water storage tank 8 is used to store working water and supply working water to the water ring pump 3; the condenser 9 is used to cool the cooling water transported from the water storage tank 8 to the water ring pump 3. The water storage tank 8 has a total water inlet 81 communicating with the total water source, a small air inlet 82 communicating with the outlet 34, a second water inlet 83 communicating with the first water outlet 32, a second water outlet 84 communicating with the condenser 9, and a total air outlet 85 for discharging gas. A ball valve is arranged at the total water inlet 81 of the water storage tank 8 to control the water inlet from the total water source; the water storage tank 8 also includes a tank body 86 for storing water. The total water inlet 81, the small air inlet 82, the second water inlet 83, the second water outlet 84, and the total air outlet 85 are all opened on the tank body 86. The total air outlet 85 and the second water inlet 83 are both arranged at the top of the tank body 86 and are far away from each other without affecting each other; the second water outlet 84 is located in the lower half of the tank body 86.

[0034] The condenser 9 includes an internal circulation passage 91 for conveying working water and an external circulation passage 92 for conveying cooling water. The internal circulation passage 91 includes a third water inlet 911 and a third water outlet 912. The third water inlet 911 is communicated with the second water outlet 84, and the third water outlet 912 is communicated with the first water inlet 31. The external circulation passage 92 is communicated with an external cooling source. The internal circulation passage 91 and the external circulation passage 92 are independently arranged. The cooling water in the external circulation passage 92 exchanges heat with the working water in the internal circulation passage 91, thereby reducing the temperature of the working water, so that the working water entering the water ring pump 3 has a lower temperature to reduce the temperature of the water ring pump 3 and ensure the working performance of the water ring pump 3.

[0035] As Figure 4 shown, the water storage tank 8 receives the working water for the operation of the water ring pump 3 through the total water inlet 81. The second water outlet 84, the third water inlet 911, the third water outlet 912 and the first water inlet 31 are sequentially fluidly connected to form an inlet path for supplying low-temperature working water from the water storage tank 8 to the water ring pump 3. The first water outlet 32 and the second water inlet 83 are connected by a pipeline to form an outlet path for conveying the working water with a higher temperature from the water ring pump 3 to the water storage tank 8. The working water provided by the inlet path forms an intake chamber for sucking gas and an outlet chamber for discharging gas with the rotor under the rotation of the eccentric rotor in the water ring pump 3. The working water reduces the temperature of the water ring pump 3 during the process of forming a water ring with the rotation of the rotor. When the working water is output from the first water outlet 32, it takes away the heat of the water ring pump 3 to reduce the temperature of the water ring pump 3. The heated working water returns to the tank body 86 through the outlet path and is cooled by the condenser 9 in the inlet path and then enters the water ring pump 3 again for work and cooling, realizing the water circulation.

[0036] As Figure 3 shown, the outlet 34, the small intake port 82 and the total outlet port 85 are sequentially fluidly connected to form an exhaust path for discharging the gas sucked by the vacuum unit 10 from the three-stage vacuum system 100. The gas discharged from the water ring pump 3 through the outlet 34 enters the water storage tank 8. Due to the density, the gas is located in the upper part of the water storage tank 8. With the water circulation of the working water, the excess gas sucked by the water ring pump 3 is extruded from the water storage tank 8 by the working water through the total outlet port 85, achieving the purpose of discharging the gas sucked by the vacuum unit 10.

[0037] An overflow port (not shown in the figure) is provided on the tank body 86. The overflow port is opened in the upper half of the tank body 86 and is located below the total outlet port 85. When the water level line of the working water in the tank body 86 reaches the overflow port, the working water reaching the overflow port flows out of the tank body 86 through the overflow port, avoiding the blockage of the total outlet port 85 by the working water in the tank body 86, so that the gas discharged from the water ring pump 3 cannot be discharged from the three-stage vacuum system 100 in time, thereby damaging the equipment.

[0038] A liquid level gauge (not shown in the figure) is provided on the tank body 86, which allows users to directly observe the water level in the tank body from outside the tank body 86, avoiding the situation where the water in the tank body 86 is too little to meet the operation of the water ring pump 3 and the situation where the water is too much to block the total air outlet 85.

[0039] In this application, two series-connected vacuum pumps and a water ring pump are used to suck the exhaust port of the extruder, improving the suction efficiency; the oil-gas separation unit 20 performs secondary cooling and secondary filtration on the gas sucked from the exhaust port to the vacuum unit 10, completely removing impurities in the gas and reducing the temperature of the gas, improving the cooling effect, protecting the roots pump and the water ring pump, extending the service life of the equipment, and being applicable to different production environments; the water circulation unit 30 cools the working water ring pump and discharges the gas sucked by the water ring pump to the external environment, ensuring the working performance of the water ring pump.

[0040] The above shows and describes the basic principles, main features and advantages of this application. Those skilled in the art should understand that this application is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of this application. Without departing from the spirit and scope of this application, this application will have various changes and improvements. The scope of protection required by this application is defined by the appended claims, the specification and their equivalents.

Claims

1. A three-stage vacuum system for an extruder, which is arranged on one side of the extruder and communicated with the exhaust port of the extruder. Characterized in that, The three-stage vacuum system includes: A vacuum unit, including a two-stage vacuum pump, a one-stage vacuum pump and a water ring pump that are connected in series in sequence; An oil-gas separation unit, which is connected between the exhaust port and the vacuum unit. The oil-gas separation unit includes a first air cooling tank, a sewage collection tank, an air filter tank and a second air cooling tank that are connected in series in sequence. The inlet of the first air cooling tank is communicated with the exhaust port, the outlet of the second air cooling tank is communicated with the two-stage vacuum pump, and a plurality of filtering components are arranged between the inlet and the outlet of the air filter tank. The first air cooling tank and the second air cooling tank are used to reduce the temperature of the air; and A water circulation unit, including a water storage tank for storing working water and a condenser for cooling the working water. The water storage tank has a total water inlet communicated with a total water source and a total air outlet for discharging gas from the three-stage vacuum system. Between the water storage tank and the water ring pump, there are independent water inlet paths, water outlet paths and exhaust paths. The condenser is arranged in the water inlet path. The water inlet path is configured to supply the working water to be unidirectionally transported from the water storage tank to the water ring pump. The water outlet path is configured to supply the working water to be unidirectionally transported from the water ring pump to the water storage tank. The exhaust path is configured to supply the gas to be unidirectionally transported from the water ring pump to the total air outlet.

2. The three-stage vacuum system according to claim 1, Characterized in that, The sewage collection tank is arranged below the first air cooling tank and the air filter tank.

3. The three-stage vacuum system according to claim 2, Characterized in that, Both the inlet and the outlet of the sewage collection tank are located at the top of the sewage collection tank and are far away from each other; the inlet of the sewage collection tank is communicated with the outlet of the first air cooling tank, and the outlet of the sewage collection tank is communicated with the inlet of the air filter tank.

4. The three-stage vacuum system according to claim 1, Characterized in that, The vacuum unit is communicated with the oil-gas separation unit through a pipeline, and a pneumatic butterfly valve is arranged in the pipeline.

5. The three-stage vacuum system according to claim 1, Characterized in that, Both the two-stage vacuum pump and the one-stage vacuum pump are Roots pumps.

6. The three-stage vacuum system according to claim 1, Characterized in that, The total air outlet of the water storage tank is located at the top of the water storage tank.

7. The three-stage vacuum system according to claim 6, Characterized in that, The water storage tank is also provided with an overflow port, and the overflow port is located in the upper half of the water storage tank and below the total air outlet of the water storage tank.

8. The three-stage vacuum system according to claim 1, Characterized in that, A liquid level gauge is arranged on the water storage tank.

9. The three-stage vacuum system according to claim 1, Characterized in that, The condenser described above includes an internal circulation passage for conveying the working water and an external circulation passage for conveying the cooling water. The internal circulation passage communicates with the water storage tank and the water ring pump, and the external circulation passage communicates with an external cooling source. The internal circulation passage and the external circulation passage are independently arranged from each other.

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