An online detection device for ethanol concentration in lactic acid bacteria fermentation

Abstract

The present invention discloses an online detection device for ethanol concentration in lactic acid bacteria fermentation, relating to the technical field of ethanol concentration detection. The device comprises a lifting rod installed in a fermentation tank. A detection cavity and a transmission cavity are defined within the lifting rod, sequentially from bottom to top. Multiple lower frames are annularly hinged to the bottom of the lifting rod. A connecting slip ring is sleeved on the outside of the lifting rod. An upper frame is hinged to the lower frame, and the other end of the upper frame is hinged to the connecting slip ring. A collection hood is bonded to the upper surface of the lower frame. Multiple one-way reflux holes are defined in the center of the collection hood. A sealing sleeve is provided at the bottom of the connecting slip ring. The device collects a small amount of fermentation liquid through the detection cavity, and then extends an ethanol vapor permeation membrane into the adjusted solution. This ensures that the ethanol vapor permeation membrane is not contaminated by excessively low pH without affecting the pH of the lactic acid bacteria fermentation liquid, thereby increasing the service life of the ethanol vapor permeation membrane.

Description

Technical Field

[0001] The present invention relates to the technical field of ethanol concentration detection, and in particular to an online detection device for ethanol concentration from lactic acid bacteria fermentation. Background Art

[0002] Ethanol is a significant byproduct of lactic acid fermentation. Especially in specialized fermentation processes, changes in ethanol concentration are closely related to the metabolic processes and fermentation efficiency of the lactic acid bacteria. Ethanol concentration not only affects the quality of the final product but also plays a crucial role in controlling and optimizing the fermentation process.

[0003] A commonly used online method for detecting ethanol concentration in lactic acid bacteria fermentation involves converting liquid ethanol into vapor-phase ethanol through an ethanol vapor permeable membrane, which is then detected using a gas sensor. A Chinese patent application (publication number: CN105044163A) discloses an online detection device for ethanol concentration in microbial fermentation, comprising a membrane sampler, a micro air pump, a sensor container, and a detection circuit. The membrane sampler comprises an ethanol vapor permeable membrane and a stainless steel vent tube. The sensor container houses a TGS2620 metal oxide semiconductor gas sensor. The detection circuit comprises a heating voltage source, a power supply voltage source, and a load resistor. One end of the stainless steel vent tube is fitted with an ethanol vapor permeable membrane and placed in contact with the fermentation liquid within the fermenter. The other end of the vent tube is connected to the inlet of the micro air pump, and the outlet of the micro air pump is connected to the inlet of the sensor container via the vent tube. The detection circuit provides a heating voltage to terminals 4 and 1 of the gas sensor, and terminal 2 of the gas sensor is connected to the load resistor. The detection circuit also provides a power supply voltage to terminal 3 of the gas sensor and the other end of the load resistor, generating a measured output voltage related to the ethanol concentration through the load resistor.

[0004] This patent and the prior art have the following technical problems in actual use:

[0005] Both this patent and the prior art directly place the ethanol vapor permeation membrane into the fermentation broth for testing. However, this method is not suitable for lactic acid bacteria fermentation because the pH value of lactic acid bacteria fermentation usually decreases during the fermentation process, usually from 6.5-7 (initial pH) to 4.0-5.0. In this low pH environment, the concentration of organic acids such as ethanol and lactic acid is high, which will accelerate membrane fouling. In a low pH environment, some organic acids and acidic substances may adhere to the membrane surface, forming pollutant accumulation, thereby affecting the permeability of the membrane, which will not only affect the service life of the ethanol vapor permeation membrane, but also affect the ethanol concentration detection results. Summary of the Invention

[0006] The purpose of the present invention is to solve the above problems and provide an online detection device for the concentration of ethanol produced by lactic acid bacteria fermentation.

[0007] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0008] A device for online detection of ethanol concentration in lactic acid bacteria fermentation comprises a lifting rod installed in a fermentation tank. A detection cavity and a transmission cavity are sequentially defined inside the lifting rod from bottom to top. A liquid inlet is defined on the outside of the detection cavity. A pH detection sensor is fixedly mounted on the inner bottom of the detection cavity. A pH adjustment tube is plugged into the inner top of the detection cavity. A liquid pipette is provided inside the detection cavity. A detection vent tube is provided inside the transmission cavity. The detection vent tube is connected to a sensor container via a micro air pump. An ethanol vapor permeable membrane is provided at the bottom end of the detection vent tube. A telescopic hole is defined between the transmission cavity and the detection cavity, and the detection vent tube can be raised and lowered along the telescopic hole.

[0009] The bottom ring of the lifting rod is hinged with multiple groups of lower frames, the outer side of the lifting rod is sleeved with a connecting slip ring, the upper frame is hinged on the lower frame, and the other end of the upper frame is hinged on the connecting slip ring. The upper surface of the lower frame is bonded with a collecting cover, and multiple groups of one-way reflux holes are opened in the middle of the collecting cover. A sealing sleeve is provided at the bottom of the connecting slip ring, which can seal the liquid inlet.

[0010] Furthermore, a telescopic tube is provided at the bottom end of the detection ventilation tube, a detection tube is provided at the bottom end of the telescopic tube, the detection tube is sealed and inserted in the telescopic hole, an ethanol vapor permeation membrane is fixedly installed at the bottom end of the detection tube, a connecting piece is provided on the outside of the detection tube, a micro cylinder is fixedly installed inside the transmission cavity, and the telescopic end of the micro cylinder is connected to the connecting piece.

[0011] Furthermore, a drainage cavity is provided inside the lifting rod, and the drainage cavity is located above the transmission cavity. The suction pipe is used to connect the drainage cavity and the detection cavity, and the top of the suction pipe is located at the inner top of the drainage cavity, and the bottom end of the suction pipe is lower than the liquid inlet. The interior of the drainage cavity is slidably connected with a drainage piston, and a through hole is provided inside the drainage piston, and a drainage pipe is inserted into the interior of the through hole. A one-way valve flap is provided inside the drainage pipe and the suction pipe. A transmission port is provided in the upper half of the drainage cavity, and a transmission protrusion is provided on the inner side of the connecting slip ring. The transmission protrusion is inserted into the drainage cavity through the transmission port, and the transmission protrusion is connected to the drainage piston through a connecting rod. A T-shaped slide rod is inserted into the interior of the connecting slip ring, and a sealing sleeve is fixedly installed at the bottom of the T-shaped slide rod.

[0012] Furthermore, a top spring is provided between the transmission protrusion and the top of the drainage cavity.

[0013] Furthermore, the lifting rod is hollow in design, and the detection ventilation tube, pH adjustment tube and control tube of the micro cylinder are all extended to the outside of the fermentation tank through the lifting rod, and the pH adjustment tube is connected to the external acid and alkali tank through a liquid pump. A connecting head is provided on the outside of the lifting rod, and the top of the connecting head is transmission-connected to the lifting cylinder, which is fixedly mounted on the fermentation tank.

[0014] Furthermore, the cross section of the detection cavity is smaller than the cross section of the liquid discharge piston.

[0015] Furthermore, the hinge between the upper frame and the lower frame is located at an end of the lower frame away from the lifting rod.

[0016] Furthermore, a hinge plate is provided at the bottom of the lifting rod, and the lower frame is hinged on the hinge plate. Multiple groups of return holes 1 are opened inside the hinge plate, and multiple groups of return holes 2 are opened inside the collection cover. Return hole 2 is arranged corresponding to return hole 1, and a one-way valve flap is also provided at the bottom of return hole 2, and the one-way valve flap is bonded to return hole 1.

[0017] Furthermore, the collecting cover is made of waterproof nylon cloth, and the upper frame and the lower frame are both made of polypropylene.

[0018] The beneficial effects of the present invention are as follows:

[0019] The present invention controls the lifting rod to descend, and the collecting cover retracts inward under the action of the buoyancy of the fermentation liquid. The collecting cover drives the connecting slip ring to slide up relative to the lifting rod through the upper frame, and the connecting slip ring drives the sealing sleeve to slide up, and the sealing sleeve opens the liquid inlet. When the connecting slip ring cannot rise, the lifting rod drives the collecting cover to descend synchronously. When the collecting cover is below the liquid surface, the fermentation liquid flows into the middle from the edges, and the multi-directional solutions are mixed in the collecting cover, and then enter the detection cavity through the liquid inlet. Compared with the existing technology, there is no need to set a stirring mechanism, and the fermentation liquid can be uniformly sampled, the detection accuracy is improved, and the structure is simple.

[0020] The present invention collects a small amount of fermentation liquid through a detection cavity, then adjusts the pH of the sampled fermentation liquid through a pH detection sensor and a pH adjustment tube, and then extends an ethanol vapor permeation membrane into the adjusted solution, converts liquid-phase ethanol into gaseous-phase ethanol through the ethanol vapor permeation membrane, and then uses a gas-sensitive sensor for detection, thereby ensuring that the ethanol vapor permeation membrane will not be contaminated due to excessively low pH without affecting the pH of the lactic acid bacteria fermentation liquid, thereby improving the service life of the ethanol vapor permeation membrane.

[0021] The present invention can simultaneously collect, mix and drain the sample liquid through the design of the collection cover structure, while minimizing the impact on the lactic acid bacteria fermentation liquid while improving the detection accuracy, and can meet the requirements of existing lactic acid bacteria fermentation ethanol concentration online detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 It is an exploded view of the present invention;

[0024] Figure 3 This is a schematic diagram of the cross-sectional structure of the collecting cover of the present invention;

[0025] Figure 4 This is a schematic diagram of the internal structure of the lifting rod of the present invention;

[0026] Figure 5 This is a schematic diagram of the cross-sectional structure of the lifting rod of the present invention;

[0027] Figure 6 This is a schematic cross-sectional view of the connection slip ring and the liquid discharge piston of the present invention;

[0028] Figure 7 This invention Figure 6 Enlarged schematic diagram of part A.

[0029] Figure numerals: 1. lifting rod; 11. connecting head; 12. hinged disc; 13. reflux hole 1; 14. detection cavity; 15. liquid inlet; 16. pH detection sensor; 17. transmission cavity; 18. telescopic hole; 19. drainage cavity; 110. transmission port; 111. suction tube; 2. lifting cylinder; 3. lower frame; 4. upper frame; 5. collecting cover; 51. reflux hole 2; 6. connecting slip ring; 61. top spring; 62. connecting rod; 63. sealing sleeve; 64. T-shaped slide bar; 7. one-way valve disc; 8. drainage piston; 81. drainage pipe; 9. detection vent pipe; 91. telescopic tube; 92. detection tube; 93. ethanol vapor permeation membrane; 94. micro cylinder; 10. pH adjustment tube. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0031] Example 1, as Figure 1-Figure 7As shown, an online detection device for ethanol concentration in lactic acid bacteria fermentation includes a lifting rod 1, which is installed in a fermentation tank. The interior of the lifting rod 1 is sequentially provided with a detection cavity 14 and a transmission cavity 17 from bottom to top. A liquid inlet 15 is provided on the outside of the detection cavity 14. A pH detection sensor 16 is fixedly installed on the inner bottom of the detection cavity 14. A pH adjustment tube 10 is plugged into the inner top of the detection cavity 14. A pipette 111 is provided inside the detection cavity 14. A detection vent pipe 9 is provided inside the transmission cavity 17. The detection vent pipe 9 is connected to the sensor container through a micro air pump. An ethanol vapor permeable membrane 93 is provided at the bottom end of the detection vent pipe 9. A telescopic hole 18 is provided between the transmission cavity 17 and the detection cavity 14, and the detection vent pipe 9 can be raised and lowered along the telescopic hole 18.

[0032] The bottom ring of the lifting rod 1 is hinged with multiple groups of lower frames 3. In this embodiment, eight groups are provided. The outer side of the lifting rod 1 is sleeved with a connecting slip ring 6. The upper frame 4 is hinged on the lower frame 3. The other end of the upper frame 4 is hinged on the connecting slip ring 6. The upper surface of the lower frame 3 is bonded with a collecting cover 5. The middle of the collecting cover 5 is provided with multiple groups of one-way reflux holes. The bottom of the connecting slip ring 6 is provided with a sealing sleeve 63, which can seal the liquid inlet 15.

[0033] Furthermore, the collecting cover 5 is made of waterproof nylon cloth. Nylon is a high-strength, wear-resistant and corrosion-resistant plastic suitable for the lactic acid bacteria fermentation environment. The upper frame 4 and the lower frame 3 are both made of polypropylene. Polypropylene has good acid resistance and can withstand the acidic environment generated during the lactic acid bacteria fermentation process. It is often used in food and medical packaging and equipment materials in the fermentation process.

[0034] During detection, the lifting rod 1 is controlled to descend, and the collecting cover 5 is retracted inwardly under the action of the buoyancy of the fermentation liquid. The collecting cover 5 drives the lower frame 3 to swing upward relative to the lifting rod 1. The lower frame 3 drives the connecting slip ring 6 to slide upward relative to the lifting rod 1 through the upper frame 4. The connecting slip ring 6 drives the sealing sleeve 63 to slide upward, and the sealing sleeve 63 opens the liquid inlet 15. When the connecting slip ring 6 cannot rise, as the lifting rod 1 continues to descend, the collecting cover 5 descends synchronously. When the collecting cover 5 is below the liquid surface, the fermentation liquid flows into the middle from the edges around it, and the multi-directional solutions are mixed in the collecting cover 5 to achieve solution mixing and improve the representativeness of the sampling. The mixed fermentation liquid enters the detection cavity 14 through the liquid inlet 15. It should be noted that at this time there is a certain distance between the liquid level and the top of the detection cavity 14, so that the detection cavity 14 has sufficient subsequent mixing space, and the ethanol vapor permeable membrane 93 will not contact the unmixed solution. Then the lifting rod 1 is controlled to rise, and the lifting rod 1 drives the collecting cover 5 to rise. , the collecting cover 5 is unfolded under the action of the gravity of the liquid, and the collecting cover 5 drives the connecting slip ring 6 to slide down relative to the lifting rod 1 through the lower frame 3 and the upper frame 4, and the connecting slip ring 6 drives the sealing sleeve 63 down, and the sealing sleeve 63 blocks the liquid inlet 15, and the solution in the collecting cover 5 flows back to the fermentation tank through multiple sets of one-way reflux holes. At this time, a small amount of mixed fermentation liquid is collected in the detection cavity 14. At this time, the pH detection sensor 16 detects the pH value of the fermentation liquid and then feeds it back to the external control system. The external control system injects an appropriate amount of acid or alkali into the detection cavity 14 through the pH adjustment tube 10 to adjust the pH. After the adjustment is completed, the detection vent pipe 9 is controlled to be inserted into the detection liquid. The detection vent pipe 9 drives the ethanol vapor permeation membrane 93 to enter the solution, and converts the liquid phase ethanol into gaseous phase ethanol through the ethanol vapor permeation membrane, and then uses the gas sensitive sensor for detection. After the detection is completed, the pipette 111 generates suction to discharge the detection solution to ensure that the pH value of the lactic acid bacteria fermentation liquid is not affected.

[0035] This embodiment adopts an inverted umbrella structure, that is, the initial state is bowl-shaped, and buoyancy can be used to simultaneously collect and mix solution samples, with high collection efficiency. It can also eliminate the effect of pH reduction on the ethanol vapor permeation membrane 93 during lactic acid bacteria fermentation, and has high detection accuracy.

[0036] Embodiment 2, based on the above embodiment, further includes: a telescopic tube 91 is provided at the bottom end of the detection ventilation tube 9, a detection tube 92 is provided at the bottom end of the telescopic tube 91, the detection tube 92 is sealed and inserted into the telescopic hole 18, an ethanol vapor permeable membrane 93 is fixedly installed at the bottom end of the detection tube 92, a connecting piece is provided on the outside of the detection tube 92, a micro cylinder 94 is fixedly installed inside the transmission cavity 17, and the telescopic end of the micro cylinder 94 is connected to the connecting piece.

[0037] By controlling the operation of the micro cylinder 94 , the micro cylinder 94 drives the detection tube 92 to be inserted into the detection solution through the connecting piece, and the control is simple.

[0038] Embodiment 3, based on the above embodiment, further includes: a drainage cavity 19 is opened inside the lifting rod 1, and the drainage cavity 19 is located above the transmission cavity 17. The liquid pipette 111 is used to connect the drainage cavity 19 and the detection cavity 14, and the top of the liquid pipette 111 is located at the inner top of the drainage cavity 19, and the bottom end of the liquid pipette 111 is lower than the liquid inlet 15. The interior of the drainage cavity 19 is slidably connected to the drainage piston 8, and the interior of the drainage piston 8 is penetrated by a through hole. A drain pipe 81 is inserted into the inside of the through hole, and a one-way valve flap 7 is provided inside the drain pipe 81 and the suction pipe 111. A transmission port 110 is provided in the upper half of the drain cavity 19, and a transmission protrusion is provided on the inner side of the connecting slip ring 6. The transmission protrusion is inserted into the drain cavity 19 through the transmission port 110. The transmission protrusion is connected to the drain piston 8 through the connecting rod 62. A T-shaped slide rod 64 is inserted into the inside of the connecting slip ring 6, and a sealing sleeve 63 is fixedly installed at the bottom of the T-shaped slide rod 64.

[0039] Furthermore, a top spring 61 is provided between the transmission protrusion and the top of the drainage cavity 19 . The setting of the top spring 61 can accelerate the sliding movement of the connecting slip ring 6 so that the sealing sleeve 63 can quickly seal the liquid inlet 15 .

[0040] After the detection is completed, the solution is located in the detection cavity 14. During the next detection, the lifting rod 1 is controlled to descend, and the collecting cover 5 is retracted inwardly under the action of the buoyancy of the fermentation liquid. The collecting cover 5 drives the lower frame 3 to swing upward relative to the lifting rod 1, and the lower frame 3 drives the connecting slip ring 6 to slide up relative to the lifting rod 1 through the upper frame 4. At this time, the connecting slip ring 6 slides up relative to the T-shaped slide bar 64, and the sealing sleeve 63 does not move. The liquid inlet 15 is still in a closed state. The connecting slip ring 6 drives the discharge piston 8 to rise through the transmission protrusion and the connecting rod 62. The discharge piston 8 sucks the detection solution into the discharge cavity 19 through the pipette 111. After the solution is absorbed, the T-shaped slide bar 64 is hung on the connecting slip ring 6. At this time, the connecting slip ring 6 drives the sealing sleeve 63 to rise through the T-shaped slide bar 64, and the liquid inlet 15 is opened. When the transmission protrusion slides to the top of the transmission port 110 When the collecting cover 5 is lowered, the collecting cover 5 cannot be further retracted. As the lifting rod 1 continues to descend, the collecting cover 5 descends synchronously. When the collecting cover 5 is below the liquid surface, the fermentation liquid flows into the middle from the edges. The multi-directional solutions are mixed in the collecting cover 5 to achieve solution mixing and improve the representativeness of the sampling. The mixed fermentation liquid enters the detection cavity 14 through the liquid inlet 15, and then the lifting rod 1 is controlled to rise. The lifting rod 1 drives the collecting cover 5 to rise, and the collecting cover 5 is unfolded under the action of the gravity of the liquid. The collecting cover 5 drives the connecting slip ring 6 to slide relative to the lifting rod 1 through the lower frame 3 and the upper frame 4. The sealing sleeve 63 slides synchronously under the action of gravity. The sealing sleeve 63 can quickly block the liquid inlet 15. At the same time, the connecting slip ring 6 drives the discharge piston 8 to descend through the transmission protrusion and the connecting rod 62, and the liquid in the discharge cavity 19 is discharged through the discharge pipe 81.

[0041] Through the arrangement of this embodiment, liquid can be automatically drained while collecting, and when absorbing liquid, there is a time difference between the rising of the sealing sleeve 63 and the rising of the connecting slip ring 6, so that complete liquid absorption is achieved. When draining liquid, the sealing sleeve 63 and the connecting slip ring 6 descend synchronously, so that the liquid inlet 15 is quickly blocked.

[0042] Example 4, based on the above examples, also includes that the lifting rod 1 is hollow in design, and the detection ventilation tube 9, the pH adjustment tube 10 and the control tube of the micro cylinder 94 are all extended to the outside of the fermentation tank through the lifting rod 1, and the pH adjustment tube 10 is connected to the external acid and alkali tank through a liquid pump. A connecting head 11 is provided on the outside of the lifting rod 1, and the top of the connecting head 11 is transmission-connected to the lifting cylinder 2. The lifting cylinder 2 is fixedly installed on the fermentation tank, and the lifting cylinder 2 stably controls the lifting and lowering of the lifting rod 1.

[0043] Through the design of this embodiment, there is no need to open additional holes on the fermentation tank, and the detection ventilation tube 9, the pH adjustment tube 10 and the control tube of the micro cylinder 94 will not come into contact with the fermentation liquid, the transmission is stable, and the overall appearance is high.

[0044] Embodiment 5, based on the above embodiment, further includes that the cross section of the detection cavity 14 is smaller than the cross section of the liquid discharge piston 8, so that the liquid discharge piston 8 can quickly suck out the detection solution when it rises.

[0045] Furthermore, the hinge between the upper frame 4 and the lower frame 3 is located at the end of the lower frame 3 away from the lifting rod 1, so that the collecting cover 5 is retracted at a smaller angle, and the connecting slip ring 6 can be raised to a greater height.

[0046] Embodiment 6, on the basis of the above embodiment, further includes: a hinge plate 12 is provided at the bottom of the lifting rod 1, the lower frame 3 is hinged on the hinge plate 12, a plurality of groups of return holes 13 are provided inside the hinge plate 12, a plurality of groups of return holes 2 51 are provided inside the collection cover 5, the return holes 2 51 are provided corresponding to the return holes 13, and a one-way valve flap 7 is also provided at the bottom of the return hole 2 51, the one-way valve flap 7 is bonded to the return hole 13, and in this embodiment, four groups of return holes 13 and four groups of return holes 2 51 are provided.

[0047] Through the arrangement of this embodiment, when the collecting cover 5 is pressed into the fermentation liquid, the fermentation liquid will not enter from below, and when the collecting cover 5 rises, the fermentation liquid inside can be better discharged through the reflux hole 2 51 and the one-way valve disc 7, and the bottom end of the collecting cover 5 can be adhered to the hinge plate 12, so that the collecting cover 5 is fixed more stably and has higher sealing performance.

[0048] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An online detection device for the concentration of ethanol fermented by lactic acid bacteria, comprising a lifting rod (1), characterized in that: The lifting rod (1) is installed in a fermentation tank. The interior of the lifting rod (1) is provided with a detection cavity (14) and a transmission cavity (17) in sequence from bottom to top. The outer side of the detection cavity (14) is provided with a liquid inlet (15). A pH detection sensor (16) is fixedly installed on the inner bottom of the detection cavity (14). A pH regulating tube (10) is plugged into the inner top of the detection cavity (14). A liquid suction tube (111) is provided inside the detection cavity (14). A detection vent pipe (9) is provided inside the transmission cavity (17). The detection vent pipe (9) is connected to the sensor container through a micro air pump. An ethanol vapor permeable membrane (93) is provided at the bottom end of the detection vent pipe (9). A telescopic hole (18) is provided between the transmission cavity (17) and the detection cavity (14). The detection vent pipe (9) can be raised and lowered along the telescopic hole (18). The bottom of the lifting rod (1) is hinged with multiple groups of lower frames (3), the outer side of the lifting rod (1) is sleeved with a connecting slip ring (6), the upper frame (4) is hinged on the lower frame (3), and the other end of the upper frame (4) is hinged on the connecting slip ring (6). The upper surface of the lower frame (3) is bonded with a collecting cover (5), and the middle of the collecting cover (5) is provided with multiple groups of one-way return holes. The bottom of the connecting slip ring (6) is provided with a sealing sleeve (63), and the sealing sleeve (63) can seal the liquid inlet (15).

2. The on-line detection device for lactic acid bacteria fermentation ethanol concentration according to claim 1, characterized in that: The bottom end of the detection vent pipe (9) is provided with a telescopic pipe (91), the bottom end of the telescopic pipe (91) is provided with a detection pipe (92), the detection pipe (92) is sealed and plugged into the telescopic hole (18), an ethanol vapor permeable membrane (93) is fixedly installed at the bottom end of the detection pipe (92), a connecting piece is provided on the outside of the detection pipe (92), a micro cylinder (94) is fixedly installed inside the transmission cavity (17), and the telescopic end of the micro cylinder (94) is connected to the connecting piece.

3. The on-line detection device for lactic acid bacteria fermentation ethanol concentration according to claim 2, characterized in that: The lifting rod (1) is provided with a drainage cavity (19) inside, and the drainage cavity (19) is located above the transmission cavity (17). The liquid suction pipe (111) is used to connect the drainage cavity (19) and the detection cavity (14), and the top of the liquid suction pipe (111) is located at the inner top of the drainage cavity (19), and the bottom of the liquid suction pipe (111) is lower than the liquid inlet (15). The drainage cavity (19) is slidably connected to the drainage piston (8), and the drainage piston (8) is provided with a through hole through the inside, and the drainage pipe (111) is inserted into the through hole. 81), a one-way valve flap (7) is provided inside the discharge pipe (81) and the suction pipe (111), a transmission port (110) is provided in the upper half of the discharge cavity (19), a transmission protrusion is provided on the inner side of the connecting slip ring (6), the transmission protrusion is inserted into the discharge cavity (19) through the transmission port (110), the transmission protrusion is connected to the discharge piston (8) through a connecting rod (62), a T-shaped slide rod (64) is inserted into the interior of the connecting slip ring (6), and a sealing sleeve (63) is fixedly installed at the bottom of the T-shaped slide rod (64).

4. The online detection device for lactic acid bacteria fermentation ethanol concentration according to claim 3, characterized in that: A top spring (61) is provided between the transmission protrusion and the top of the drainage cavity (19).

5. The on-line detection device for lactic acid bacteria fermentation ethanol concentration according to claim 4, characterized in that: The lifting rod (1) is hollow in design, and the detection ventilation tube (9), the pH adjustment tube (10) and the control tube of the micro cylinder (94) are all extended to the outside of the fermentation tank through the lifting rod (1), and the pH adjustment tube (10) is connected to the external acid and alkali tank through a liquid pump. A connector (11) is provided on the outside of the lifting rod (1), and the top of the connector (11) is transmission-connected to the lifting cylinder (2), and the lifting cylinder (2) is fixedly installed on the fermentation tank.

6. The on-line detection device for lactic acid bacteria fermentation ethanol concentration according to claim 5, characterized in that: The cross section of the detection cavity (14) is smaller than the cross section of the discharge piston (8).

7. The on-line detection device for lactic acid bacteria fermentation ethanol concentration according to claim 6, characterized in that: The hinge point between the upper frame (4) and the lower frame (3) is located at an end of the lower frame (3) away from the lifting rod (1).

8. The on-line detection device for lactic acid bacteria fermentation ethanol concentration according to claim 7, characterized in that: A hinge plate (12) is provided at the bottom of the lifting rod (1), and the lower frame (3) is hinged on the hinge plate (12). A plurality of return holes (13) are provided inside the hinge plate (12), and a plurality of return holes (51) are provided inside the collecting cover (5). The return holes (51) are provided corresponding to the return holes (13), and a one-way valve flap (7) is also provided at the bottom of the return hole (51), and the one-way valve flap (7) is bonded to the return hole (13).

9. The online detection device for lactic acid bacteria fermentation ethanol concentration according to claim 1, characterized in that: The collecting cover (5) is made of waterproof nylon cloth, and the upper frame (4) and the lower frame (3) are both made of polypropylene.

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