Air supply and temperature control system for floating microalgae photobioreactor and application thereof

Abstract

This invention relates to the field of microalgae cultivation technology, specifically to an aeration and temperature control system for a floating microalgae photobioreactor and its application. The system includes a floating platform containing several culture vessels, with an aeration system connecting the culture vessels. A drive mechanism is also located above the floating platform. This aeration and temperature control system for the floating microalgae photobioreactor, and its application, uses an air bladder to drive the overall floating and sinking motion. Utilizing the air bladder's strong corrosion resistance, the system ensures stable and reliable floating and sinking. During the fixed-distance ascent, the insert rod inside the limiting tube rotates through the cooperation of a protrusion and a spiral groove, thereby controlling the sequential ejection of three sets of limiting blocks to form three different mechanical limiting points, achieving multi-level precise control of the culture vessel immersion depth.

Description

Technical Field

[0001] This invention relates to the field of microalgae cultivation technology, and more specifically, to a gas supply and temperature control system for a floating microalgae photobioreactor and its application. Background Technology

[0002] The floating microalgae culture system mainly consists of an open raceway tank and a closed photobioreactor. This system promotes microalgae photosynthesis and biomass accumulation by artificially controlling nutrients, temperature, pH and aeration, and using sunlight or artificial light sources. Its advantages are simple operation and low cost.

[0003] The invention patent application with application number CN201710859033.5 discloses a recirculating seawater aquaculture system based on a microalgae membrane bioreactor, including an aquaculture pond connected to a photobioreactor. The photobioreactor is connected to a microalgae concentration pond via a water pump. An ultrafiltration membrane module is installed inside the microalgae concentration pond. The outlet of the ultrafiltration membrane module is connected to the aquaculture pond via a water pump. A wastewater outlet and a drainage pipe are located at the center of the aquaculture pond. This invention can effectively remove pollutants such as free ammonia and phosphate from aquaculture wastewater through the absorption of microalgae cultivated in the photobioreactor. The concentrations of free ammonia and reactive phosphate in the effluent of the ultrafiltration membrane module are both below the detection limit. The wastewater is then circulated back to the aquaculture pond, effectively realizing the recycling of aquaculture water. After the microalgae are harvested, they are processed into feed and fed back to the aquaculture pond, realizing the recycling of nutrients during the aquaculture process.

[0004] Compared with traditional equipment, existing conventional floating microalgae cultivation systems usually lack depth adjustment functions, making it difficult to achieve precise stratified control of cultivation depth. Their buoyancy supply mostly relies on independent air pumps or mechanical propulsion devices, which consumes a lot of energy and has a complex structure. At the same time, the electronic control components are susceptible to seawater corrosion, affecting the stability and reliability of long-term operation.

[0005] In view of this, we propose an air supply and temperature control system for a floating microalgae photobioreactor and its application. Summary of the Invention

[0006] The purpose of this invention is to provide an air supply and temperature control system for a floating microalgae photobioreactor and its application. Through the synergistic structure of airbags and mechanical limiting tubes, multi-level precise control of the immersion depth of the culture vessel is achieved, thereby solving the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An aeration and temperature control system for a floating microalgae photobioreactor includes a floating platform with several culture vessels inside, an aeration system between the culture vessels, and a drive mechanism above the floating platform.

[0009] The floating platform includes a grid frame, a pair of airbags located on its outer side, and a limiting tube for controlling the immersion depth of the incubator. The limiting tube includes a round tube, a round rod disposed inside it, several limiting blocks sliding in the grooves on the outer wall of the round rod, a spring disposed on the inner wall of the limiting blocks, and an insert rod sliding in the round hole at the top of the round rod. The outer wall of the round tube is provided with through grooves corresponding to the positions of the limiting blocks, the inner wall of the round hole at the top of the round rod is provided with a spiral groove, and the bottom end of the insert rod is provided with a protrusion.

[0010] After the airbag is inflated, it causes the grid frame to float up. The insert rod moves upward at a fixed distance at different times, driving the protrusion to move along the spiral groove. As the round rod rotates 45°, the limiting block on it extends out of the through groove in sequence.

[0011] The gas supply system includes a fixed gas pipe, a piston pipe that slides within the fixed gas pipe, and a gas supply pipe connected to several incubators.

[0012] In this configuration, the piston tube moves upward synchronously with the insertion rod, first diverting the carbon dioxide gas in the fixed air tube into the airbag, and then sealing the diversion tube.

[0013] The drive mechanism includes a crossbeam plate, several electric push rods disposed on its top surface, and a lifting plate driven by it.

[0014] This setting involves the lifting plate moving the insertion rod and piston tube together.

[0015] In the technical solution of the present invention, the grid frame includes a square frame, several connecting frames welded and fixed to the inner wall of the square frame, and a pair of placement frames welded and fixed to the outer wall of the square frame.

[0016] In the technical solution of the present invention, the airbag includes a bag body, a fixing ring that is snapped and fixed to the outer wall of the bag body and fixed to the end of the connecting frame by bolts, an air inlet pipe and an air extraction pipe that are threaded to the top of the bag body, a piston plate that is slidably connected to the inside of the bag body, and a pair of rings integrally formed on the inner wall of the bag body. The bottom end of the bag body is provided with several regularly distributed through holes that are connected inside and outside. The air inlet pipe and the air extraction pipe are respectively provided with a one-way air inlet valve and a one-way air outlet valve. The other end of the air extraction pipe is connected to a miniature vacuum pump.

[0017] The above setup controls the raising and lowering of the grid frame via airbags, ensuring long-term stable operation of the grid frame's raising and lowering process in highly corrosive marine environments.

[0018] In the technical solution of the present invention, the circular tube is fixedly connected to the bottom surface of the crossbeam plate by bolts, and two parallel limiting rings are welded on the outer wall of the circular tube. The circular rod is rotatably connected to the inside of the circular tube.

[0019] In the technical solution of the present invention, the included angle between the vertical projections of two adjacent limiting blocks is 45°. The two ends of the spring are respectively welded and fixed to the outer wall of the limiting block and the groove of the outer wall of the round rod. The elastic force of the spring pushes the limiting block to move outward. The insertion rod is slidably connected to the inside of the crossbeam plate. The protrusion and the insertion rod are integrally formed.

[0020] This setting allows the lower, middle, and upper sets of limiting blocks to pop out sequentially at different time points, precisely dividing the upward floating process of the grid frame into multiple predetermined depths. This enables step-by-step, programmable, and precise control of the immersion depth of the culture vessel, ensuring that it remains in the most suitable light and temperature layer and optimizing growth conditions.

[0021] In the technical solution of the present invention, the incubator includes a plastic cover, a vent pipe heat-fused to the outer wall of the plastic cover, an exhaust valve threaded to the top of the plastic cover, and a monitoring module snapped and fixed to the top of the plastic cover. The monitoring module is equipped with a temperature sensor for real-time monitoring of the liquid temperature inside the plastic cover.

[0022] This setup uses carbon dioxide injected from below the pipe wall to circulate the algae solution inside the plastic cover, reducing the amount of microalgae adsorbed onto the inner wall of the plastic cover.

[0023] In the technical solution of the present invention, the top flange of the fixed air pipe is connected to the bottom surface of the crossbeam plate, and the outer wall of the fixed air pipe is integrally formed with a lower pipe and an upper pipe. The lower pipe is used to connect to an external air supply pump through a pipeline, and the upper pipe is connected to the air inlet pipe.

[0024] In the technical solution of the present invention, the piston tube is slidably connected to the inside of the fixed air tube, and an air hole adapted to the size of the upper through pipe is opened on the outer wall of the piston tube. A connecting rod is welded to the top of the piston tube. A hose is connected between the fixed air tube and the air supply pipe. The hose connects the fixed air tube and the air supply pipe at the bottom. A connecting pipe is connected between adjacent air supply pipes by flanges.

[0025] In the above setup, the piston tube can move synchronously with the insertion rod. By utilizing the air holes on the outer wall of the piston tube, the culture vessel can be controlled to gradually float upward while reducing the need for additional piston tube drive equipment.

[0026] In the technical solution of the present invention, the electric actuator is fixedly connected to the top surface of the crossbeam plate by screws, the lifting plate is snapped and fixed to the end of the electric actuator telescopic rod, and a sealing cover is sleeved on the outside of the electric actuator, and the sealing cover is snapped and fixed to the top surface of the crossbeam plate.

[0027] This feature, through the movement of the lifting plate, synchronously drives the displacement of the insertion rod and piston tube, providing the prerequisite for precise, step-by-step, programmable control of the immersion depth of the culture vessel.

[0028] On the other hand, the present invention provides an application of the gas supply and temperature control system of a floating microalgae photobioreactor, which is the application of the above-mentioned floating microalgae photobioreactor gas supply and temperature control system in the cultivation of *Phaeodactylum tricornutum*.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. The gas supply and temperature control system of this floating microalgae photobioreactor and its application: The floating and sinking of the whole is driven by the inflation and deflation of the air bladder. The strong corrosion resistance of the air bladder ensures the stability and reliability of the floating and sinking action. During the fixed-distance rise of the rod in the limiting tube, the cooperation of the protrusion and the spiral groove drives the round rod to rotate, thereby controlling the three sets of limiting blocks to pop out in sequence, forming three different mechanical limiting points. This realizes multi-level precise control of the immersion depth of the culture vessel, and accurately stabilizes the culture vessel at different depths, so that the algal solution grows in the optimal light and temperature layer, thereby improving the photosynthetic efficiency and biomass production of *Phaeodactylum tricornutum*.

[0031] 2. The gas supply and temperature control system of the floating microalgae photobioreactor and its application, the linkage structure of the gas supply system and the lifting drive mechanism, realize the efficient integrated utilization of gas resources. The piston tube is lifted and lowered under the drive of the electric push rod. The air holes on its wall are aligned with the upper pipe in the initial stage of the rise, and carbon dioxide is injected into the air bag to provide buoyancy. The carbon dioxide used to supply algae cultivation provides buoyancy for the lifting and lowering of the system, eliminating the need for a separate air bag inflation device, which greatly reduces the system energy consumption and complexity. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0033] Figure 2 This is a schematic diagram of the floating platform in this invention;

[0034] Figure 3 This is a schematic diagram of the grid frame structure in this invention;

[0035] Figure 4 This is a cross-sectional schematic diagram of the airbag structure in this invention;

[0036] Figure 5 This is a cross-sectional schematic diagram of the limiting tube in this invention;

[0037] Figure 6 This is a cross-sectional schematic diagram of a portion of the limiting tube in this invention;

[0038] Figure 7 This is a cross-sectional view of the circular rod in this invention;

[0039] Figure 8 This is a schematic diagram of the incubator in this invention;

[0040] Figure 9 This is a cross-sectional schematic diagram of the gas supply system in this invention;

[0041] Figure 10 For the present invention Figure 9 An enlarged schematic diagram of part A in the middle;

[0042] Figure 11 This is a cross-sectional schematic diagram of the drive mechanism in this invention;

[0043] Explanation of reference numerals in the attached figures:

[0044] 100. Floating platform; 110. Grid frame; 111. Square frame; 112. Connecting frame; 113. Placement frame; 120. Airbag; 121. Airbag body; 1210. Through hole; 122. Fixing ring; 123. Air inlet pipe; 124. Air extraction pipe; 125. Piston plate; 126. Ring; 130. Limiting tube; 131. Round tube; 1310. Through groove; 1311. Limiting ring; 132. Round rod; 1320. Spiral groove; 133. Limiting block; 134. Spring; 135. Insert rod; 1350. Protrusion;

[0045] 200. Incubator; 210. Plastic cover; 220. Ventilation tube; 230. Exhaust valve; 240. Monitoring module;

[0046] 300. Gas supply system; 310. Fixed gas pipe; 311. Lower pipe; 312. Upper pipe; 320. Piston pipe; 321. Air port; 330. Connecting rod; 340. Flexible hose; 350. Gas supply pipe; 360. Connecting pipe;

[0047] 400. Drive mechanism; 410. Crossbeam plate; 420. Electric actuator; 430. Lifting plate; 440. Sealing cover. Detailed Implementation

[0048] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0049] Please see Figures 1-4 As shown, this embodiment provides a technical solution:

[0050] An aeration and temperature control system for a floating microalgae photobioreactor, used in the cultivation of *Phaeodactylum tricornutum*, includes a floating platform 100, which contains several culture vessels 200. An aeration system 300 is provided between the culture vessels 200, and a drive mechanism 400 is provided above the floating platform 100.

[0051] Specifically, the floating platform 100 includes a grid frame 110, a pair of air bladders 120 located on its outer side, and a limiting tube 130 for controlling the immersion depth of the incubator 200.

[0052] Furthermore, the grid frame 110 includes a square frame 111, several connecting frames 112 welded and fixed to the inner wall of the square frame 111, and a pair of placement frames 113 welded and fixed to the outer wall of the square frame 111.

[0053] Furthermore, the airbag 120 includes a bag body 121, a fixing ring 122 that is snapped and fixed to the outer wall of the bag body 121 and fixed to the end of the connecting frame 112 by bolts, an air inlet pipe 123 and an air extraction pipe 124 that are threaded to the top of the bag body 121, a piston plate 125 that is slidably connected to the inside of the bag body 121, and a pair of rings 126 integrally formed on the inner wall of the bag body 121. The bottom end of the bag body 121 is provided with several regularly distributed through holes 1210 that are open inside and out. The air inlet pipe 123 and the air extraction pipe 124 are respectively provided with a one-way air inlet valve and a one-way air outlet valve. The other end of the air extraction pipe 124 is connected to a miniature vacuum pump.

[0054] Furthermore, after the gas enters the airbag 120 through the parallel air intake pipe 123, it pushes the piston plate 125 downward inside the bladder 121, pushing seawater out of the through hole 1210 into the bladder 121. After increasing the internal volume of the bladder 121, the buoyancy generated causes the grid frame 110 to float upward outside the limiting pipe 130 and be restricted by the limiting block 133 below, controlling the top of the incubator 200 to float above the sea surface. When the external micro vacuum pump is started, the gas in the bladder 121 is extracted through the air extraction pipe 124, pushing the piston plate 125 upward until it contacts the upper ring 126. Then, seawater rushes into the bladder 121, and the grid frame 110 and all incubators 200 are submerged below the sea surface again. This setting controls the raising and lowering of the grid frame 110 through the airbag 120, ensuring the long-term stable operation of the raising and lowering process of the grid frame 110 in the highly corrosive ocean.

[0055] Please see Figures 1-7 As shown, in this embodiment, the limiting tube 130 includes a circular tube 131, a circular rod 132 disposed inside it, several limiting blocks 133 sliding in the grooves on the outer wall of the circular rod 132, a spring 134 disposed on the inner wall of the limiting block 133, and an insert rod 135 sliding in the circular hole at the top of the circular rod 132. A through groove 1310 is opened on the outer wall of the circular tube 131 at the position corresponding to the limiting block 133. A spiral groove 1320 is provided on the inner wall of the circular hole at the top of the circular rod 132. A protrusion 1350 is provided at the bottom of the insert rod 135. After the airbag 120 is inflated, it causes the grid frame 110 to float up. The insert rod 135 moves upward at a fixed distance at different times, driving the protrusion 1350 to move along the spiral groove 1320. Every time the circular rod 132 rotates 45°, the limiting blocks 133 on it will extend out of the through groove 1310 in sequence.

[0056] Specifically, the round tube 131 is fixedly connected to the bottom surface of the crossbeam plate 410 by bolts. Two limit rings 1311 arranged in parallel vertically are welded on the outer wall of the round tube 131. The round rod 132 is rotatably connected to the inside of the round tube 131.

[0057] Furthermore, the included angle between the vertical projections of two adjacent limiting blocks 133 is 45°. The two ends of the spring 134 are welded and fixed to the outer wall of the limiting block 133 and the groove of the outer wall of the round rod 132, respectively. The elastic force of the spring 134 pushes the limiting block 133 to move outward. The insertion rod 135 is slidably connected to the inside of the crossbeam plate 410. The protrusion 1350 and the insertion rod 135 are integrally formed.

[0058] Furthermore, during the fixed-distance upward movement of the insertion rod 135, the protrusion 1350 at the bottom of the insertion rod 135 moves along the spiral groove 1320, causing the round rod 132 to rotate 45° clockwise, connecting the groove below the round tube 131 with the through groove 1310 below the round tube 131. Under the elastic force of the spring 134, the limiting block 133 inside the groove below the round tube 131 extends to the outside of the through groove 1310. As the insertion rod 135 continues to move upward, the middle and upper limiting blocks 133 extend out of the corresponding through grooves 1310 in sequence. This setting, by allowing the lower, middle and upper sets of limiting blocks to pop out at different time points, precisely divides the upward movement of the grid frame 110 into multiple predetermined depths, realizing the step-by-step, programmable, and precise control of the immersion depth of the culture vessel 200, ensuring that it stays in the most suitable light and temperature layer and optimizing growth conditions.

[0059] Please see Figure 8 As shown, in this embodiment, the incubator 200 includes a plastic cover 210, a vent pipe 220 heat-fused to the outer wall of the plastic cover 210, an exhaust valve 230 threaded to the top of the plastic cover 210, and a monitoring module 240 snapped and fixed to the top of the plastic cover 210. The monitoring module 240 is equipped with a temperature sensor for real-time monitoring of the liquid temperature inside the plastic cover 210.

[0060] Furthermore, the plastic cover 210 is used to provide conditions for the cultivation of *Phaeodactylum tricornutum*, the vent pipe 220 is used for the injection of external carbon dioxide, the exhaust valve 230 is used to expel excess gas inside the plastic cover 210, and the monitoring module 240 is equipped with a temperature sensor to better control the immersion depth of the incubator 200. This setting allows the algal solution inside the plastic cover 210 to circulate by injecting carbon dioxide from below the pipe wall, reducing the adsorption of microalgae on the inner wall of the plastic cover 210.

[0061] Please see Figures 9-10As shown, in this embodiment, the gas supply system 300 includes a fixed gas pipe 310, a piston pipe 320 that slides within the fixed gas pipe 310, and a gas supply pipe 350 that is connected to several incubators 200. The piston pipe 320 moves upward synchronously with the insertion rod 135, first diverting the carbon dioxide gas in the fixed gas pipe 310 into the air bag 120, and then sealing the diversion pipe.

[0062] Specifically, the top flange of the fixed air pipe 310 is connected to the bottom surface of the crossbeam plate 410. The outer wall of the fixed air pipe 310 is integrally formed with a lower pipe 311 and an upper pipe 312. The lower pipe 311 is used to connect to an external air supply pump through a pipe, and the upper pipe 312 is connected to the air inlet pipe 123.

[0063] Furthermore, the piston tube 320 is slidably connected to the inside of the fixed air tube 310. The outer wall of the piston tube 320 is provided with an air hole 321 that matches the size of the upper through tube 312. A connecting rod 330 is welded to the top of the piston tube 320. A hose 340 is connected between the fixed air tube 310 and the air supply tube 350. The hose 340 connects the fixed air tube 310 and the air supply tube 350 at the bottom. A connecting tube 360 ​​is connected between adjacent air supply tubes 350 by a flange.

[0064] Furthermore, the piston tube 320 in the fixed trachea 310 moves upward with the connecting rod 330, connecting the air hole 321 with the upper tube 312. The carbon dioxide injected into the fixed trachea 310 through the lower tube 311 is diverted into the air inlet tube 123, while the gas is injected into the interior of the capsule 121. During the subsequent ascent, the piston tube 320 can also close the upper tube 312. In this setting, the piston tube 320 can move synchronously with the insertion rod 135. By utilizing the air hole 321 opened on the outer wall of the piston tube 320, the incubator 200 is controlled to gradually float upward while reducing the need for additional driving of the piston tube 320.

[0065] Please see Figures 1-11 As shown, in this embodiment, the drive mechanism 400 includes a crossbeam plate 410, a plurality of electric push rods 420 disposed on its top surface, and a lifting plate 430 driven by it. The lifting plate 430 drives the insertion rod 135 and the piston tube 320 to move together.

[0066] Specifically, the electric actuator 420 is fixedly connected to the top surface of the crossbeam plate 410 by screws, the lifting plate 430 is snapped and fixed to the end of the telescopic rod of the electric actuator 420, and a sealing cover 440 is fitted on the outside of the electric actuator 420, which is snapped and fixed to the top surface of the crossbeam plate 410.

[0067] Furthermore, the crossbeam plate 410 is used to fix the extended frame fixed on the coast to ensure that the overall structure will not drift away with the tide. After the electric actuator 420 is activated, it is used to control the movement of the lifting plate 430, which in turn drives the insertion rod 135 and the piston tube 320 to move synchronously. The sealing cover 440 is used to prevent the electric actuator 420 from being disturbed by seawater. This setting, through the movement of the lifting plate 430, synchronously drives the displacement of the insertion rod 135 and the piston tube 320, providing the prerequisite for the step-by-step, programmable, and precise control of the immersion depth of the culturer 200.

[0068] This embodiment also provides an application of the gas supply and temperature control system of the floating microalgae photobioreactor, which is the application of the above-mentioned floating microalgae photobioreactor gas supply and temperature control system in the cultivation of Phaeodactylum tricornutum.

[0069] When using the floating microalgae photobioreactor of the present invention, the external air supply pump is started to inject carbon dioxide into the fixed air pipe 310 through the lower pipe 311, and then into the air supply pipe 350 through the hose 340. Meanwhile, carbon dioxide is injected into the plastic cover 210 through the air pipe 220, so that the algal liquid in the plastic cover 210 circulates and reduces the adsorption of microalgae on the inner wall of the plastic cover 210.

[0070] Then, as the sun rises in the morning and the sea surface temperature increases, several electric actuators 420 in the control drive mechanism 400 drive the lifting plate 430 to rise, which in turn drives the insertion rod 135 in the limit tube 130 and the connecting rod 330 in the air supply system 300 to move upward at a fixed distance.

[0071] Subsequently, the protrusion 1350 at the bottom of the insertion rod 135 moves along the spiral groove 1320, causing the round rod 132 to rotate 45° clockwise, connecting the groove below the round tube 131 with the through groove 1310 below the round tube 131. Meanwhile, the limiting block 133 inside the groove below the round tube 131 extends to the outside of the through groove 1310 under the elastic force of the spring 134. At this time, the piston tube 320 in the fixed air tube 310 moves upward with the connecting rod 330, opening the air hole 321. After being connected to the upper tube 312, the carbon dioxide injected into the fixed air tube 310 by the lower tube 311 is diverted into the air inlet tube 123, and pushes the piston plate 125 to move down inside the capsule 121, pushing seawater out of the through hole 1210 into the capsule 121. After increasing the internal volume of the capsule 121, the buoyancy generated causes the grid frame 110 to float up outside the limiting tube 130 and be restricted by the limiting block 133 below, controlling the top of the incubator 200 to float above the sea surface;

[0072] Subsequently, as the sea surface temperature gradually rises, the control lifting plate 430 is raised at a fixed distance. With the piston tube 320 already sealing the upper through pipe 312, this action allows the incubator 200 to gradually float out of the sea surface. When the connecting frame 112 is restricted from continuing to float by the limiting ring 1311 above the round tube 131, four-fifths of the total volume of the incubator 200 is exposed above the sea surface, reaching its maximum floating height and fully absorbing sunlight.

[0073] Then, when the temperature reaches its highest point at noon, the external micro vacuum pump is activated to extract the gas from the capsule 121 through the suction pipe 124, pushing the piston plate 125 upward until it contacts the upper ring 126. Subsequently, seawater rushes into the capsule 121, and the grid frame 110 and all the incubators 200 are submerged below the sea level again. At this time, the external air pump is briefly turned off, and the electric actuator 420 is controlled to drive the lifting plate 430 downward, thereby driving the insertion rod 135 and the piston pipe 320 to reset. From afternoon to sunset, the above process is repeated to keep the incubators 200 continuously submerged below the sea level at night to maintain a stable internal temperature.

[0074] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the specification and its equivalents.

Claims

1. A gas supply and temperature control system for a floating microalgae photobioreactor, characterized in that: It includes a floating platform, which contains several incubators, and an air supply system is provided between the incubators. A drive mechanism is also provided above the floating platform. The floating platform includes a grid frame, a pair of airbags located on its outer side, and a limiting tube for controlling the immersion depth of the culture vessel. The limiting tube includes a round tube, a round rod disposed inside it, several limiting blocks sliding in the grooves on the outer wall of the round rod, a spring disposed on the inner wall of the limiting blocks, and an insert rod sliding in the round hole at the top of the round rod. The outer wall of the round tube is provided with through grooves corresponding to the positions of the limiting blocks. The inner wall of the round hole at the top of the round rod is provided with a spiral groove. The bottom end of the insert rod is provided with a protrusion. After the airbags are inflated, they cause the grid frame to float up. The insert rod moves upward at a fixed distance at different times, driving the protrusion to move along the spiral groove. Every time the round rod rotates 45°, the limiting blocks on it will extend out of the through groove in sequence. The gas supply system includes a fixed gas tube, a piston tube that slides within the fixed gas tube, and a gas supply tube connected to several incubators. The piston tube moves upward synchronously with the insertion rod, first diverting carbon dioxide gas from the fixed gas tube into the air bag, and then sealing the diversion pipe. The drive mechanism includes a crossbeam plate, several electric push rods disposed on its top surface, and a lifting plate driven by it. The lifting plate drives the insertion rod and piston tube to move together.

2. The gas supply and temperature control system of the floating microalgae photobioreactor according to claim 1, characterized in that: The grid frame includes a square frame, several connecting frames welded and fixed to the inner wall of the square frame, and a pair of placement frames welded and fixed to the outer wall of the square frame.

3. The gas supply and temperature control system of the floating microalgae photobioreactor according to claim 2, characterized in that: The airbag includes a body, a fixing ring that is snapped onto the outer wall of the airbag and fixed to the end of the connecting frame by bolts, an air inlet pipe and an air extraction pipe that are threaded to the top of the airbag, a piston plate that is slidably connected to the inside of the airbag, and a pair of rings integrally formed on the inner wall of the airbag. The bottom end of the airbag has several regularly distributed through holes that are open inside and out. One end of the air inlet pipe is provided with a one-way air inlet valve, one end of the air extraction pipe is provided with a one-way air outlet valve, and the other end of the air extraction pipe is connected to a miniature vacuum pump.

4. The gas supply and temperature control system for the floating microalgae photobioreactor according to claim 3, characterized in that: The circular tube is fixedly connected to the bottom surface of the crossbeam plate by bolts. Two parallel limiting rings are welded on the outer wall of the circular tube. The circular rod is rotatably connected to the inside of the circular tube.

5. The gas supply and temperature control system for the floating microalgae photobioreactor according to claim 4, characterized in that: The included angle between the vertical projections of two adjacent limiting blocks is 45°. The two ends of the spring are respectively welded and fixed to the outer wall of the limiting block and the groove of the outer wall of the round rod. The elastic force of the spring pushes the limiting block to move outward. The insertion rod is slidably connected to the inside of the crossbeam plate. The protrusion and the insertion rod are integrally formed.

6. The gas supply and temperature control system for the floating microalgae photobioreactor according to claim 5, characterized in that: The incubator includes a plastic cover, a vent pipe heat-fused to the outer wall of the plastic cover, an exhaust valve threaded to the top of the plastic cover, and a monitoring module snapped and fixed to the top of the plastic cover. The monitoring module is equipped with a temperature sensor for real-time monitoring of the liquid temperature inside the plastic cover.

7. The gas supply and temperature control system for the floating microalgae photobioreactor according to claim 6, characterized in that: The top flange of the fixed air pipe is connected to the bottom surface of the crossbeam plate. The outer wall of the fixed air pipe is integrally formed with a lower pipe and an upper pipe. The lower pipe is used to connect to an external air supply pump through a pipeline, and the upper pipe is connected to the air inlet pipe.

8. The gas supply and temperature control system for the floating microalgae photobioreactor according to claim 7, characterized in that: The piston tube is slidably connected to the inside of the fixed air tube. The outer wall of the piston tube has an air hole that matches the size of the upper through pipe. A connecting rod is welded to the top of the piston tube. A hose is connected between the fixed air tube and the air supply pipe. The hose connects the fixed air tube and the air supply pipe at the bottom. A connecting pipe is connected between adjacent air supply pipes by flanges.

9. The gas supply and temperature control system for the floating microalgae photobioreactor according to claim 8, characterized in that: The electric actuator is fixedly connected to the top surface of the crossbeam plate by screws. The lifting plate is snapped and fixed to the end of the electric actuator telescopic rod. A sealing cover is fitted on the outside of the electric actuator and snapped and fixed to the top surface of the crossbeam plate.

10. An application of an air supply and temperature control system for a floating microalgae photobioreactor, characterized in that: This refers to the application of the gas supply and temperature control system of the floating microalgae photobioreactor as described in claim 9 in the cultivation of *Phaeodactylum tricornutum*.

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