Circulating filtration device for tea oil purification

Abstract

A circulating filtering device for tea oil purification comprises a primary filtering assembly and at least one secondary filtering assembly, the primary filtering assembly comprises a primary filtering cylinder, the upper portion of an inner cavity of the primary filtering cylinder is connected with a primary filtering net, the top of the primary filtering cylinder is connected with an oil inlet pipe, and the bottom of the primary filtering cylinder is connected with an oil outlet control valve; the secondary filtering assembly comprises a secondary filtering cylinder, a secondary filtering net is arranged in the secondary filtering cylinder, the lower portion of the primary filtering cylinder is connected to the top of the secondary filtering cylinder through a primary oil outlet pipe, an oil outlet is formed in the bottom of the secondary filtering cylinder, the oil outlet is located between the secondary filtering net and the cylinder wall of the secondary filtering cylinder, and the oil outlet is communicated with an oil gathering pipe. The oil gathering pipe is communicated with the oil return pipe; the oil return pipe is connected to the top of the primary filter cartridge or the secondary filter cartridge of the next filter assembly; and pumps are arranged on the primary oil outlet pipe and the oil return pipe. According to the invention, through multi-stage circulating filtration, efficient purification of tea oil is realized, and the adsorption effect is enhanced by injecting microbubbles.

Description

Technical Field

[0001] The present invention relates to the field of tea oil filtration and purification, and particularly to a circulating filtration device for tea oil purification. Background Art

[0002] Tea oil, also known as camellia oil, is a natural vegetable oil extracted from the seeds of camellia oleifera trees. It has attracted much attention due to its nutritional value and wide range of uses. Its nutritional value is reflected in: being rich in high unsaturated fatty acids, with the oleic acid content in tea oil being as high as over 80%, approaching that of olive oil, which helps to reduce cholesterol and maintain cardiovascular health; being rich in vitamins and antioxidant components, rich in vitamin E, squalene, polyphenols, etc., having the effects of antioxidation and anti-aging; having a high smoke point, being suitable for high-temperature cooking, with good stability and not easily producing harmful substances.

[0003] The quality of tea oil is related to the extraction process. Circulating filtration is an important link in the tea oil purification process, especially playing a key role in improving the quality and stability of the oil product during the refining stage. Circulating filtration can remove physical impurities. There may be residual fruit shell debris, plant fibers, colloids and other fine particles in the crude oil after pressing or leaching. Circulating filtration can gradually remove these impurities and improve the transparency of the oil product.

[0004] Currently, circulating filtration is achieved by passing tea oil through filter cloths of different mesh numbers. The higher the mesh number of the filter cloth, the higher the filtration purity, but at the same time, the resistance to tea oil is also greater. Based on the characteristic that tea oil has a high viscosity, it further improves the blocking effect of the filter cloth on tea oil, thereby restricting the efficiency of the circulating filtration of tea oil. Summary of the Invention

[0005] The purpose of the present invention is to provide a circulating filtration device for tea oil purification to solve the above technical problems.

[0006] A circulating filtration device for tea oil purification includes a primary filtration component and at least one set of secondary filtration components. The primary filtration component includes a primary filter cylinder. At the upper part of the inner cavity of the primary filter cylinder, a primary filter screen is connected. At the top of the primary filter cylinder, an oil inlet pipe is connected, and at the bottom, an oil outlet control valve is connected. The secondary filtration component includes a secondary filter cylinder with a secondary filter screen disposed inside. The lower part of the primary filter cylinder is connected to the top of the secondary filter cylinder through a primary oil outlet pipe. At the bottom of the secondary filter cylinder, there is an oil outlet located between the secondary filter screen and the barrel wall of the secondary filter cylinder. The oil outlet is communicated with a collecting oil pipe, and the collecting oil pipe is communicated with a return oil pipe. The return oil pipe is connected to the top of the primary filter cylinder or the secondary filter cylinder of the next filtration component. Pumps are provided on the primary oil outlet pipe and the return oil pipe.

[0007] Preferably, the primary filter cartridge and the secondary filter cartridge are provided with a temperature control jacket. The temperature control jacket includes a heating element and a housing. The housing and the cavity formed by the primary filter cartridge and the secondary filter cartridge contain dielectric water. The housing is of a double-layer structure with an internal insulation layer. The temperature control jacket maintains a constant temperature inside the primary filter cartridge and the secondary filter cartridge through hot water circulation. The insulation layer is designed to reduce heat dissipation and improve the heat transfer efficiency to the camellia oil.

[0008] Preferably, the temperature control jacket controls the temperature inside the primary filter cartridge to be 60°C and the temperature inside the secondary filter cartridge to be 50°C. The temperature of 60°C inside the primary filter cartridge is intended to reduce the viscosity to improve efficiency, and the temperature of 50°C inside the secondary filter cartridge is intended to protect the antioxidant components and reduce the oxidation risk.

[0009] Preferably, the primary filter screen and the secondary filter screen are made of metal. At the top of the secondary filter cartridge, there is an oil inlet rotating body with rotational freedom. The oil inlet rotating body is connected to the primary oil outlet pipe or the return pipe. At the bottom of the oil inlet rotating body, multiple oil outlet nozzles are connected. At the bottom of the oil inlet rotating body, a rotating rod is connected, and a scraper is connected to the rotating rod. The edge of the scraper contacts the secondary filter screen. A rotating wheel is connected to the oil inlet rotating body. The rotating wheel rotates under the drive of an external drive source, driving the scraper to continuously scrape off the impurities attached to the secondary filter screen.

[0010] Preferably, the primary filter cartridge and the secondary filter cartridge are provided with constant pressure valves, which are designed to maintain a constant pressure in the primary filter cartridge and the secondary filter cartridge.

[0011] Preferably, an air flow pipeline is connected to the inner wall of the secondary filter cartridge, and an air nozzle is connected to the air flow pipeline. An air valve is connected to the outer wall of the secondary filter cartridge. By controlling the air valve, gas can be injected into the air flow pipeline, and the gas will spray out from the air nozzle and enter the camellia oil in the form of microbubbles. Utilizing the surface tension of the microbubbles, impurities are adsorbed, and at the same time, the rising speed in the viscous camellia oil is relatively slow, enhancing the adsorption effect.

[0012] Preferably, a quantitative reflux mechanism is further included. The quantitative reflux mechanism includes a mounting plate connected to the lower part of the secondary filter cartridge. A ratchet is connected to the mounting plate, and a rotating seat and a pawl seat are also connected. A triggering member is rotatably provided on the rotating seat, and a pawl is rotatably provided on the pawl seat. The pawl and the pawl seat are connected by a first torsion spring. The pawl cooperates with the ratchet, and the triggering member and the rotating seat are connected by a second torsion spring. The return pipe and the collecting pipe are communicated through a rotating wheel cavity. A flow wheel is arranged in the rotating wheel cavity. A rotating shaft is key-connected to the flow wheel. The rotating shaft penetrates the rotating wheel cavity and is connected to a pushing pawl, and the pushing pawl acts on the ratchet. A pressing member is connected to the bottom of the ratchet, and the pressing member acts on the triggering member. A waste oil control valve is further connected to the lower part of the secondary filter cartridge. A button is provided on the waste oil control valve, and the button is electrically connected to the waste oil control valve and the pump.

[0013] Preferably, the inner wall of the secondary filter cartridge is connected to a flushing pipeline, the flushing pipeline is connected to a nozzle, and the outer wall of the secondary filter cartridge is connected to a flushing valve. By controlling the flushing valve, pressurized flushing medium fluid is controllably injected into the flushing pipeline to assist the scraping operation of the scraper, and residual foam and attached impurities can be flushed away.

[0014] Beneficial effects: Compared with the prior art, the circulating filtration device for purifying tea oil of the present invention has multi-stage circulating filtration to achieve efficient purification of tea oil, and the tea oil at different stages is stably controlled by the temperature control jacket, thereby reducing the viscosity of the tea oil while ensuring the quality of the tea oil; the filtration effect is improved by setting a secondary filter screen, and it has reliable impact resistance, and the flow resistance of the tea oil is reduced together with the temperature; for tiny impurities, microbubbles are injected and the surface tension of the microbubbles is utilized to adsorb the impurities, while the rising speed in the viscous tea oil is slower, thereby enhancing the adsorption effect; after the secondary filtration, the amount of refluxed tea oil is controlled by a quantitative reflux mechanism, so that the foam layer suspended on the surface of the tea oil is retained in the secondary filter cartridge and discharged after the linked waste oil control valve is opened; the impurities remaining on the inner wall of the secondary filter cartridge and the secondary filter screen are also flushed by setting a backwashing mechanism, thereby avoiding the influence of residual impurities on the subsequent tea oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0016] Figure 1 : A schematic diagram of the structure of a circulating filtration device for purifying tea oil according to the present invention;

[0017] Figure 2 : Schematic diagram of the structure of the primary filter component and the secondary filter component;

[0018] Figure 3 : Schematic diagram of the structure of the temperature control jacket;

[0019] Figure 4 : Schematic diagram of the structure of the air flow pipeline and flushing pipeline in the secondary filter cartridge;

[0020] Figure 5 : Schematic diagram of the structure of the quantitative reflux mechanism;

[0021] In the figure: primary filter cartridge 1, primary filter screen 2, oil inlet pipe 3, oil outlet control valve 4, primary oil outlet pipe 5, secondary filter cartridge 6, secondary filter screen 7, oil collection pipe 8, oil return pipe 9, heating element 10, cover 11, oil inlet swivel 12, oil outlet nozzle 13, scraper 14, runner 15, constant pressure valve 16, air nozzle 17, air valve 18, mounting plate 19, ratchet 20, swivel seat 21, claw seat 22, trigger member 23, ratchet 24, first torsion spring 25, second torsion spring 26, runner cavity 27, flow wheel 28, rotating shaft 29, push claw 30, extrusion member 31, waste oil control valve 32, button 33, nozzle 34, flushing valve 35. DETAILED DESCRIPTION

[0022] In order to make the purpose, features and advantages of the present invention more clearly understood, the following Figures 1 - 5 The specific implementation of the present invention is described in detail. Several embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0023] Reference Figure 1 and Figure 2 A circulating filtration device for purifying tea oil includes a primary filtration component and at least one group of secondary filtration components. The primary filtration component includes a primary filter cartridge 1. The upper part of the inner cavity of the primary filter cartridge 1 is connected to a primary filter screen 2. The top of the primary filter cartridge 1 is connected to an oil inlet pipe 3. The tea oil to be filtered enters the primary filter cartridge 1 through the oil inlet pipe 3, and the primary filtration is completed after passing through the primary filter screen 2 to filter out large-volume impurities in the tea oil.

[0024] The lower part of the primary filter cartridge 1 is connected to an oil outlet control valve 4, and the lower part of the primary filter cartridge 1 is connected to the secondary filter assembly through a primary oil outlet pipe 5. The primary oil outlet pipe 5 is connected to a pump. When the primary filter assembly performs primary filtration, the oil outlet control valve 4 is in a closed state, and the tea oil after preliminary filtration will be pumped into the secondary filter assembly through the primary oil outlet pipe 5 under the action of the pump for subsequent re-filtration operations.

[0025] The secondary filtration component includes a secondary filter cartridge 6, and a secondary filter screen 7 is built inside the secondary filter cartridge 6. The primary oil outlet pipe 5 is connected to the top of the secondary filter cartridge 6. The secondary filter screen 7 divides the inner cavity of the secondary filter cartridge 6 into two parts. The tea oil after primary filtration enters the secondary filter cartridge 6 and first enters the secondary filter screen 7, and then enters the outside of the secondary filter screen 7 after passing through the secondary filter screen 7. Under the action of the secondary filter cartridge 7, secondary filtration is carried out to filter out smaller impurities and improve the purification efficiency. An oil outlet is provided at the bottom of the secondary filter cartridge 6, and the oil outlet is located between the secondary filter screen 7 and the barrel wall of the secondary filter cartridge 6. The oil outlet is communicated with a collecting oil pipe 8, and the collecting oil pipe 8 is communicated with a return oil pipe 9. When there is only one group of secondary filtration components, the return oil pipe 9 is connected to the top of the primary filter cartridge 1 of the primary filtration component. When there are multiple groups of secondary filtration components, it is connected to the top of the secondary filter cartridge of the next filtration component to complete multi-stage filtration, and the return oil pipe 9 of the last group of secondary filtration components is connected to the top of the primary filter cartridge 1 of the primary filtration component. A pump is also provided on the return oil pipe 9.

[0026] According to common knowledge, tea oil is a fluid with viscosity. During the process of cyclic filtration, its viscous resistance hinders the efficiency of cyclic filtration. The temperature control in the cyclic filtration link directly affects the viscosity physical properties and chemical stability of tea oil. Reasonable temperature management can not only improve the filtration efficiency, but also maximize the retention of the nutritional components of tea oil and extend the shelf life. The recommended temperature for cyclic filtration is usually controlled at 50–60 °C. At this temperature, the viscosity of tea oil is moderate, which can not only ensure fluidity but also avoid the oxidation risk caused by high temperature.

[0027] Reference appendix Figure 5 In the present invention, temperature control jackets are provided outside both the primary filter cartridge 1 and the secondary filter cartridge 6 to control the temperature of the tea oil between 40–70 °C. The temperature control jackets maintain a constant temperature through hot water circulation. The temperature control jacket includes a heating element 10 and a housing 11. The housing 11 is a double-layer structure with an inner insulation layer to reduce heat dissipation and improve the heat transfer efficiency to the tea oil. The medium water is provided in the cavity formed by the housing 11 and the primary filter cartridge 1 and the secondary filter cartridge 6. After the heating element 10 is powered on, it heats the medium water, and then controls the temperature of the tea oil in the primary filter cartridge 1 and the secondary filter cartridge 6. In this embodiment, staged precise temperature control is adopted. In the primary filter cartridge 1, the temperature is appropriately increased to 60 °C to reduce the viscosity and improve the efficiency. In the secondary filter cartridge 6, the temperature is reduced to 50 °C to protect the antioxidant components and reduce the oxidation risk.

[0028] Reference appendix Figure 2, the primary filter screen 2 and the secondary filter screen 7 are made of metal. Compared with traditional filter cloth, they can resist the fluid impact of tea oil. The impurities in the tea oil fluid will be intercepted in the secondary filter screen 7, and the impurities attached to the secondary filter screen 7 will block the flow rate of tea oil. Based on the characteristic that the secondary filter screen 7 is made of metal, in this embodiment, a scraping component is provided to scrape the impurities attached to its surface. Specifically, an oil inlet rotating body 12 with rotational freedom is provided at the top of the secondary filter cylinder 6. The oil inlet rotating body 12 is connected to the primary oil outlet pipe 5 or the return pipe 9. A plurality of oil outlet nozzles 13 are connected to the bottom of the oil inlet rotating body 12. The oil outlet nozzles 13 can introduce tea oil into the secondary filter cylinder 6. A rotating rod is connected to the bottom of the oil inlet rotating body 12, and a scraping plate 14 is connected to the rotating rod. The edge of the scraping plate 14 contacts the secondary filter screen 7. A rotating wheel 15 is connected to the oil inlet rotating body 12. The rotating wheel 15 rotates under the drive of an external drive source, thereby driving the scraping plate to continuously scrape the impurities attached to the secondary filter screen 7.

[0029] Reference appendix Figure 1 and Figure 2 , in this embodiment, the amount of tea oil injected into the primary filter cylinder 1 each time is fixed. After the primary filter cylinder 1 completes preliminary filtration and heating, it is pumped into the secondary filter cylinder 6. Constant pressure valves 16 are provided on the primary filter cylinder 1 and the secondary filter cylinder 6 to maintain a constant pressure in the primary filter cylinder 1 and the secondary filter cylinder 6.

[0030] In the present invention, when using the secondary filter screen 7 to filter tea oil, although it has stability and can be scraped, its mesh count is lower than that of traditional filter cloth, and the filtration efficiency for tiny impurities is not high. In this embodiment, by injecting bubbles, the suspended impurities are wrapped to the surface layer of the tea oil. Due to the surface tension effect, microbubbles can adsorb hydrophobic or partially lipophilic impurities, rise to the oil layer surface by buoyancy, and form a foam layer. At the same time, the viscosity of the tea oil is relatively high, and the rising speed of the microbubbles is slow, which can prolong the contact time with the impurities and enhance the adsorption effect, thereby improving the filtration effect.

[0031] Reference appendix Figure 4 , specifically, an air flow pipeline is connected to the inner wall of the secondary filter cylinder 6, an air nozzle 17 is connected to the air flow pipeline, and an air valve 18 is connected to the outer wall of the secondary filter cylinder 6. By controlling the air valve 18, gas can be injected into the air flow pipeline, and the gas will be ejected from the air nozzle 17 and enter the tea oil in the form of microbubbles, and gradually float upward under buoyancy, adsorbing and wrapping the suspended impurities to the surface layer of the tea oil, achieving the effect of filtering tiny impurities.

[0032] Reference appendix Figure 5, Further, after the secondary filtration is completed in the secondary filter cartridge 6, an impurity foam layer floats on its surface layer. Before the filtered tea oil is refluxed to the primary filter cartridge 1, the foam layer on the top needs to be removed. Based on the fact that the amount of tea oil injected each time is fixed, the present invention further includes a quantitative reflux mechanism, which can intercept a fixed amount of tea oil in the secondary filter cartridge 6 for waste oil treatment. In this embodiment, the quantitative reflux mechanism includes a mounting plate 19 connected to the lower part of the secondary filter cartridge 6. A ratchet wheel 20 is connected to the mounting plate 19, and a rotating seat 21 and a pawl seat 22 are also connected. A trigger member 23 is rotatably provided on the rotating seat 21, and a pawl 24 is rotatably provided on the pawl seat 22. The pawl 24 is connected to the pawl seat 22 through a first torsion spring 25. The pawl 24 cooperates with the ratchet wheel 20, and the trigger member 23 is connected to the rotating seat 21 through a second torsion spring 26; The return oil pipe 9 and the oil collecting pipe 8 are communicated through a runner cavity 27. A flow wheel 28 is arranged in the runner cavity 27. The flow wheel 28 is key-connected with a rotating shaft 29. The rotating shaft 29 penetrates through the runner cavity 27 and is connected with a push pawl 30. The push pawl 30 acts on the ratchet wheel 20; A pressing member 31 is connected to the bottom of the ratchet wheel 20, and the pressing member 31 acts on the trigger member 23. A waste oil control valve 32 is also connected to the lower part of the secondary filter cartridge 6. A button 33 is arranged on the waste oil control valve 32. The button 33 is electrically connected to the pump on the waste oil control valve 32 and the return oil pipe.

[0033] Based on the premise that the amount of tea oil for circulating filtration is fixed, after the secondary filtration is completed, the pump is started to extract the tea oil in the secondary filter cartridge 6 to the next secondary filter cartridge or reflux it to the primary filter cartridge 1. During this process, the waste oil control valve 32 is in the closed state. When the tea oil flows through the flow wheel 28, it pushes the flow wheel to rotate, and drives the push pawl 30 below to rotate. The rotating push pawl 30 gradually pushes the ratchet wheel 20 to rotate. The ratchet wheel 20 rotates unidirectionally under the action of the pawl 24. When the extraction amount of the tea oil reaches the target amount (less than the initial amount of tea oil), the pressing member 31 rotates one circle with the ratchet wheel 20 and presses the trigger member 23 to make it rotate. The tilted end triggers the button 33, causing the pump to stop, and at the same time the waste oil control valve 32 opens, and the remaining waste oil is discharged from the secondary filter cartridge 6.

[0034] Refer to the appendix Figure 4 , After the waste oil is discharged, this embodiment can also clean the inner wall of the secondary filter cartridge 6 and the secondary filter screen 7. The medium for cleaning is preferably the tea oil after circulating filtration, and the remaining impurities and foam are rinsed outside the secondary filter cartridge. Specifically, a flushing pipeline is connected to the inner wall of the secondary filter cartridge 6, and a nozzle 34 is connected to the flushing pipeline. A flushing valve 35 is connected to the outer wall of the secondary filter cartridge 6. By controlling the flushing valve 35, pressurized flushing medium fluid can be controllably injected into the flushing pipeline. The fluid will spray out from the nozzle 34, scour the inner wall of the secondary filter cartridge 6 and the secondary filter screen 7, assist the scraping operation of the scraper, and can scour down the remaining foam and attached impurities.

[0035] The circulating filtration device for purifying tea oil of the present invention has multi-stage circulating filtration to achieve efficient purification of tea oil. The temperature control jacket is provided to stably control the tea oil at different stages, and the viscosity of the tea oil is reduced under the premise of ensuring the quality of the tea oil. The filtering effect is improved by providing a secondary filter screen, and the device has reliable impact resistance, and the flow resistance of the tea oil is reduced together with the temperature. For tiny impurities, microbubbles are injected and the surface tension of the microbubbles is utilized to adsorb the impurities, and the rising speed in the viscous tea oil is slow, thereby enhancing the adsorption effect. After the secondary filtration, the amount of refluxed tea oil is controlled by a quantitative reflux mechanism, so that the foam layer suspended on the surface of the tea oil is retained in the secondary filter cartridge and discharged after the linked waste oil control valve 32 is opened. The impurities remaining on the inner wall of the secondary filter cartridge and the secondary filter screen are also washed by providing a backwashing mechanism to avoid the influence of the residual impurities on the subsequent tea oil.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A circulating filtration device for tea oil purification, characterized in that: It includes a primary filtration component and at least one set of secondary filtration components. The primary filtration component includes a primary filter cartridge (1). A primary filter screen (2) is connected to the upper part of the inner cavity of the primary filter cartridge (1). An oil inlet pipe (3) is connected to the top of the primary filter cartridge (1), and an oil outlet control valve (4) is connected to the bottom. The secondary filtration component includes a secondary filter cartridge (6). A secondary filter screen (7) is built inside the secondary filter cartridge (6). The lower part of the primary filter cartridge (1) is connected to the top of the secondary filter cartridge (6) through a primary oil outlet pipe (5). An oil outlet is provided at the bottom of the secondary filter cartridge (6), and the oil outlet is located between the secondary filter screen (7) and the barrel wall of the secondary filter cartridge (6). The oil outlet is communicated with a collecting oil pipe (8), and the collecting oil pipe (8) is communicated with a return oil pipe (9). The return oil pipe (9) is connected to the top of the primary filter cartridge (1) or the secondary filter cartridge of the next filtration component. Pumps are provided on the primary oil outlet pipe (5) and the return oil pipe (9).

2. The circulating filtration device for tea oil purification according to claim 1, wherein: A temperature control jacket is provided outside the primary filter cartridge (1) and the secondary filter cartridge (6). The temperature control jacket includes a heating element (10) and a housing (11). A medium water is built inside the cavity formed by the housing (11) and the primary filter cartridge (1) and the secondary filter cartridge (6). The housing (11) is of a double-layer structure with a built-in heat insulation layer.

3. The circulating filtration device for tea oil purification according to claim 2, characterized in that: The temperature control jacket controls the temperature inside the primary filter cartridge (1) to be 60 °C and the temperature inside the secondary filter cartridge (6) to be 50 °C.

4. The circulating filtration device for tea oil purification according to claim 2, characterized in that: The primary filter screen (2) and the secondary filter screen (7) are made of metal. A rotatable oil inlet body (12) is provided at the top of the secondary filter cartridge (6). The rotatable oil inlet body (12) is connected to the primary oil outlet pipe (5) or the return oil pipe (9). A plurality of oil outlet nozzles (13) are connected to the bottom of the rotatable oil inlet body (12). A rotating rod is connected to the bottom of the rotatable oil inlet body (12), and a scraping plate (14) is connected to the rotating rod. The edge of the scraping plate (14) contacts the secondary filter screen (7). A rotating wheel (15) is connected to the rotatable oil inlet body (12).

5. The circulating filtration device for tea oil purification according to claim 4, characterized in that: Pressure maintaining valves (16) are provided on the primary filter cartridge (1) and the secondary filter cartridge (6).

6. The circulating filtration device for tea oil purification according to claim 5, characterized in that: An air flow pipeline is connected to the inner wall of the secondary filter cartridge (6), and an air nozzle (17) is connected to the air flow pipeline. An air valve (18) is connected to the outer wall of the secondary filter cartridge (6).

7. The circulating filtration device for tea oil purification according to claim 6, wherein: It further includes a metering reflux mechanism. The metering reflux mechanism includes a mounting plate (19) connected to the lower part of the secondary filter cartridge (6). A ratchet wheel (20) is connected to the mounting plate (19), and a rotating seat (21) and a pawl seat (22) are also connected. A triggering member (23) is rotatably provided on the rotating seat (21), and a pawl (24) is rotatably provided on the pawl seat (22). The pawl (24) is connected to the pawl seat (22) through a first torsion spring (25). The pawl (24) cooperates with the ratchet wheel (20), and the triggering member (23) is connected to the rotating seat (21) through a second torsion spring (26). The return oil pipe (9) is communicated with the oil collecting pipe (8) through a runner cavity (27). A flow runner (28) is arranged in the runner cavity (27). The flow runner (28) is key-connected with a rotating shaft (29). The rotating shaft (29) penetrates through the runner cavity (27) and is connected with a pushing pawl (30). The pushing pawl (30) acts on the ratchet wheel (20). The bottom of the ratchet wheel (20) is connected with an extrusion member (31). The extrusion member (31) acts on the triggering member (23). A waste oil control valve (32) is further connected to the lower part of the secondary filter cartridge (6). A button (33) is arranged on the waste oil control valve (32). The button (33) is electrically connected to the waste oil control valve (32) and the pump.

8. The circulating filtration device for tea oil purification according to claim 7, characterized in that: A flushing pipeline is connected to the inner wall of the secondary filter cartridge (6). A nozzle (34) is connected to the flushing pipeline. A flushing valve (35) is connected to the outer wall of the secondary filter cartridge (6).

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