Pneumatic conveying cement cooling system using double cold sources for concrete mixing plant

Abstract

The invention discloses a concrete mixing plant pneumatic conveying cement cooling system utilizing double cold sources, which uses cold air for pneumatic conveying, combines cooling liquid for double cooling of cement, and utilizes the synergistic effect of the gas-liquid double cold sources to effectively shorten the cement cooling time, improve the cement temperature drop amplitude and improve the cement cooling efficiency. It is ensured that the cement warehousing temperature is stabilized within a certain range, the negative influence of high temperature on the concrete performance is fundamentally eliminated, the cooling efficiency is greatly improved through the composite cooling mode, the limitation of a traditional single cooling mode is broken through, and the industrial pain point that cement is cooled slowly in the high-temperature season is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cement conveying of concrete mixing station, and particularly relates to a cement cooling system for pneumatic conveying of concrete mixing station using double cold sources. BACKGROUND

[0002] The traditional cement cooling of concrete mixing station adopts natural air cooling or single-stage water cooling, which has defects of slow cooling speed and limited temperature drop range. Especially under high-temperature working conditions in summer, the high temperature of cement can cause a series of quality problems such as uncontrolled setting time and uneven strength growth of concrete. Meanwhile, the existing cooling equipment generally has the contradiction between high energy consumption and low temperature control accuracy, and excessive dependence on mechanical refrigeration leads to increased operating costs, while simple energy-saving measures can increase the quality risk. SUMMARY

[0003] Therefore, the present application provides a cement cooling system for pneumatic conveying of concrete mixing station using double cold sources, which shortens the cooling time of cement, improves the temperature drop range, and ensures that the cement storage temperature is stable within a certain range, thereby fundamentally eliminating the negative effects of high temperature on the performance of concrete.

[0004] A cement cooling system for pneumatic conveying of concrete mixing station using double cold sources, comprising a cold air generating and conveying unit, a cement feeding mechanism, a gas-material mixing chamber and a double-layer conveying pipeline,

[0005] The cold air generating and conveying unit is used for generating and conveying cold air to the gas-material mixing chamber, and the gas outlet of the cold air generating and conveying unit is connected with the air inlet of the gas-material mixing chamber.

[0006] The cement feeding mechanism is used for storing and conveying cement to the gas-material mixing chamber, and the discharge port of the cement feeding mechanism is connected with the feeding port of the gas-material mixing chamber, and the discharge port of the gas-material mixing chamber is connected with the feeding port of the double-layer conveying pipeline.

[0007] The double-layer conveying pipeline is provided with cooling liquid in the interlayer, and the interlayer is connected with the external cooling liquid circulating mechanism, and a plurality of guide plates are arranged on the inner wall of the double-layer conveying pipeline along the length direction.

[0008] Preferably, the cold air generating and conveying unit comprises a refrigeration compressor, a condenser connected with the refrigerant outlet of the refrigeration compressor through a pipeline, an expansion valve connected with the refrigerant outlet of the condenser through a pipeline, an evaporator connected with the refrigerant outlet of the expansion valve through a pipeline, and a fan, the refrigerant outlet of the evaporator is connected with the refrigerant inlet of the refrigeration compressor through a pipeline, the air outlet of the evaporator is connected with a first conveying pipe, the fan is connected with a second conveying pipe, and the first conveying pipe and the second conveying pipe are connected to the air inlet of the gas-material mixing chamber in parallel.

[0009] Preferably, the cement feeding mechanism comprises a cement bin, a screw feeder or a rotary valve for conveying the cement in the cement bin to the air-material mixing chamber.

[0010] Preferably, the air-material mixing chamber is in an inverted conical structure, and the top of the air-material mixing chamber is provided with a feeding port, and the side of the air-material mixing chamber is provided with an air inlet.

[0011] Preferably, the double-layer conveying pipeline comprises a pipe outer shell, a pipe inner shell arranged in the pipe outer shell, and a clamping layer for arranging the cooling liquid formed between the pipe outer shell and the pipe inner shell, and the two ends of the pipe outer shell are provided with connecting flanges, and the pipe outer shell is provided with a cooling liquid inlet and a cooling liquid outlet, and the cooling liquid inlet and the cooling liquid outlet are connected with the two ends of the cooling liquid circulating mechanism, respectively.

[0012] Preferably, the cooling liquid circulating mechanism comprises a temperature sensor arranged on the pipe outer shell for detecting the temperature of the cooling liquid in the clamping layer, a first conveying pipe connected with the cooling liquid inlet on the pipe outer shell, a cooling liquid circulating pump connected with the first conveying pipe, and a cooling liquid storage tank connected with the cooling liquid circulating pump, and the cooling liquid storage tank is connected with a second conveying pipe, and the second conveying pipe is connected with the cooling liquid outlet on the pipe outer shell, and a flow meter is arranged on the first conveying pipe.

[0013] Preferably, the inner wall of the pipe inner shell is further provided with an inner concave spiral groove or a corrugated groove.

[0014] Preferably, the pipe outer shell is further provided with a pressure sensor for detecting the pressure inside the pipeline and an exhaust valve for exhausting the excess gas inside the pipeline, and the exhaust valve is provided with a silencer.

[0015] Preferably, the flow guide plate is composed of stainless steel plates orthogonally intersected, and the plate surface of the stainless steel plate and the axial end surface of the double-layer conveying pipeline form an included angle.

[0016] Preferably, the included angle between the plate surface of the stainless steel plate and the axial end surface of the double-layer conveying pipeline is 15-30°, and the spacing between the two adjacent groups of flow guide plates is 3-5 times the inner diameter of the double-layer conveying pipeline.

[0017] The beneficial effects of the present application are:

[0018] 1. The present application uses cold air for pneumatic conveying, and combines the double cooling of the cooling liquid on the cement, utilizes the synergistic effect of the gas-liquid double cooling source, effectively shortens the cooling time of the cement, improves the temperature drop range of the cement, ensures that the cement entering the bin has a stable temperature within a certain range, and fundamentally eliminates the negative effects of high temperature on the performance of concrete. This composite cooling method greatly improves the cooling efficiency, breaks through the limitations of the traditional single cooling mode, and solves the industry pain point of slow cement cooling in high temperature seasons.

[0019] 2、Double layer conveying pipeline adopts double layer design, the inner wall of the pipeline is designed as concave spiral shape, which not only prolongs the cement conveying path and increases the refrigeration space, but also can make the cement dispersion more uniform through the flow guide plate, and the flow guide plate can disrupt the flow direction of the cement, strengthen the mixing of cold and hot medium, combined with the cooling effect of the cooling liquid, in the corresponding space, the full cooling of the cement is maximized.

[0020] 3、By setting the cooling liquid circulating mechanism on the double layer conveying pipeline, the state of the cooling liquid can be monitored in real time, combined with the electromagnetic flow meter, the electric valve opening degree can be dynamically adjusted to ensure that the temperature of the cooling liquid is always within the range of 5-10℃, so that the temperature of the cement at the outlet of the double layer conveying pipeline is stably within a certain range, which not only reduces the error of manual adjustment, but also reduces the energy consumption.

[0021] 4、And by adding an insulating layer outside the double layer conveying pipeline, the cold energy loss is reduced and the energy consumption is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0023] Figure 1 is a structural schematic diagram of the concrete mixing station pneumatic conveying cement cooling system of the present application.

[0024] Figure 2 is a structural schematic diagram of the double layer conveying pipeline of the present application.

[0025] Figure 3 is a schematic diagram of the double layer conveying pipeline of the present application with the pipe shell deleted.

[0026] Figure 4 is a half cutaway schematic diagram of the double layer conveying pipeline of the present application with the pipe shell deleted.

[0027] The meanings of the reference numerals in the drawings are as follows:

[0028] 1 is a refrigeration compressor,

[0029] 2 is a condenser,

[0030] 3 is an expansion valve,

[0031] 4 is an evaporator,

[0032] 5 is a fan,

[0033] 6 is a gas material mixing chamber,

[0034] 7 is a double-layer conveying pipe, 71 is a guide plate, 72 is a pipe outer shell, 73 is a pipe inner shell, 74 is a interlayer,

[0035] 8 is a temperature sensor,

[0036] 9 is a cement bin,

[0037] 10 is a screw feeder or a rotary valve,

[0038] 11 is a first conveying pipe,

[0039] 12 is a cooling liquid circulating pump,

[0040] 13 is a cooling liquid storage tank,

[0041] 14 is a second conveying pipe,

[0042] 15 is a flow meter,

[0043] 16 is a pressure sensor,

[0044] 17 is an exhaust valve,

[0045] 18 is a silencer,

[0046] 19 is an electrically controlled regulating valve. DETAILED DESCRIPTION

[0047] In order to make the objectives, technical solutions and advantages of the present application clearer and more comprehensible, the present application will be described below by specific embodiments shown in the drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of the known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0048] The terms used in the present disclosure are merely for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The singular forms "a", "an" and "the" used in the present disclosure and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0049] It should be understood that although the terms first, second, third, etc. can be used in the present disclosure to describe various information, these information should not be limited to these terms and should not be understood as indicating or implying relative importance. These terms are only used to distinguish one type of information from another type of information. For example, without departing from the scope of the present disclosure, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information.

[0050] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0051] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0052] To better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings.

[0053] This invention provides a pneumatic conveying cement cooling system for a concrete mixing plant utilizing dual cold sources, comprising a cold air generation and conveying unit, a cement feeding mechanism, an air-material mixing chamber 6, and a double-layer conveying pipeline 7.

[0054] The cold air generating and conveying unit is used to generate cold air and convey it to the gas-material mixing chamber 6. The gas outlet of the cold air generating and conveying unit is connected to the air inlet of the gas-material mixing chamber 6.

[0055] The cement feeding mechanism is used to store cement and transport it to the air-material mixing chamber 6. The outlet of the cement feeding mechanism is connected to the inlet of the air-material mixing chamber 6, and the outlet of the air-material mixing chamber 6 is connected to the inlet of the double-layer conveying pipe 7. Cold air and cement are mixed in the air-material mixing chamber 6. During the mixing process, the cold air initially cools the cement and can also be used as a conveying power to blow the cement into the double-layer conveying pipe 7.

[0056] Coolant is provided in the interlayer 74 of the double-layer conveying pipe 7. When cement is blown into the double-layer conveying pipe 7 by cold air, the coolant can cool the cement a second time so that the temperature of the discharged cement drops to about 18°C.

[0057] Specifically, the cold air generation and delivery unit includes a refrigeration compressor 1, a condenser 2 connected to the refrigerant outlet of the refrigeration compressor 1 via a pipeline, an expansion valve 3 connected to the refrigerant outlet of the condenser 2 via a pipeline, an evaporator 4 connected to the refrigerant outlet of the expansion valve 3 via a pipeline, and a fan 5. The refrigerant outlet of the evaporator 4 is connected to the refrigerant inlet of the refrigeration compressor 1 via a pipeline. The outlet of the evaporator 4 is connected to a first delivery pipe, and the fan 5 is connected to a second delivery pipe. The first delivery pipe and the second delivery pipe are connected in parallel to the inlet of the gas-fuel mixing chamber 6. In this embodiment, the refrigeration compressor 1 is a scroll compressor with a cooling capacity ranging from 60 to 120 kW.

[0058] The cement feeding mechanism includes a cement silo 9 and a screw feeder or rotary valve 10 for conveying cement from the cement silo 9 to the air-material mixing chamber 6.

[0059] The air-material mixing chamber 6 has an inverted cone shape, with a feed inlet at the top, an air inlet on the side, and a discharge outlet at the bottom. Cold air enters the air-material mixing chamber 6 through the air inlet, while cement powder conveyed by the screw feeder or rotary valve 10 enters the air-material mixing chamber 6 through the top. During the mixing process, the cold air initially cools the cement, and at the same time, the cold air can also serve as a conveying force to blow the cement from the discharge outlet at the bottom of the air-material mixing chamber 6 through the pipeline into the double-layer conveying pipeline 7.

[0060] The shell of the double-layer conveying pipe 7 is a double-layer hollow structure. Coolant is provided in the interlayer 74 between the inner and outer shells, and the interlayer is connected to the external coolant circulation mechanism. Multiple sets of guide plates 71 are provided on the inner wall of the double-layer conveying pipe 7 along its length.

[0061] Specifically, the double-layer conveying pipe 7 includes an outer shell 72 and an inner shell 73 disposed within the outer shell. A jacket 74 for distributing coolant is formed between the outer shell 72 and the inner shell 73. Multiple sets of guide plates 71 are arranged at equal intervals along the length of the inner shell 73. Connecting flanges are provided at both ends of the outer shell 72, and a coolant inlet and a coolant outlet are provided on the outer shell 72. In this embodiment, the outer diameter of the inner shell 73 is 15-25 mm smaller than the inner diameter of the outer shell 72, and the two ends of the inner shell 73 are welded and fixed to the flange face of the connecting flange of the outer shell 72. This forms a 15-25 mm wide annular jacket 74 between the inner shell 73 and the outer shell 72. To effectively ensure heat conduction, the inner shell 73 is made of copper-aluminum composite material with a thermal conductivity ≥200 W / (m·K). Through the inner shell 73, heat conduction can be quickly achieved between the coolant and the cement, further reducing the temperature of the cement.

[0062] The guide plates 71 inside the inner shell 73 are composed of orthogonally intersecting stainless steel plates, with an angle between the surface of the stainless steel plates and the axial end face of the double-layer conveying pipe 7. Preferably, the angle between the surface of the stainless steel plates and the axial end face of the double-layer conveying pipe 7 is 15-30°, and the spacing between two adjacent sets of guide plates 71 is 3-5 times the inner diameter of the double-layer conveying pipe 7.

[0063] In a preferred embodiment, the inner wall of the inner shell 73 is further provided with a concave spiral groove or a corrugated groove, or the inner shell 73 is a spiral-patterned tube. When the inner wall of the inner shell 73 is provided with a concave spiral groove or the inner shell 73 is a spiral-patterned tube, the ratio between the thread pitch of the spiral and the inner diameter of the inner shell 73 is 1.5-2.

[0064] In a preferred embodiment, the outer shell 72 of the double-layer conveying pipe 7 is wrapped with a layer of rock wool insulation material with a thickness of 50mm-80mm, and the thermal conductivity of the rock wool insulation material is ≤0.04W / (m·K).

[0065] The coolant inlet of the outer casing 72 is connected to the outlet of the coolant circulation mechanism, and the coolant outlet of the outer casing 72 is connected to the inlet of the coolant circulation mechanism. This allows the coolant to circulate between the outer casing 72 and the inner casing 73, ensuring that the temperature of the coolant remains within the range of 5-10℃, thereby guaranteeing the cooling effect of the cement inside the pipe.

[0066] Specifically, the coolant circulation mechanism includes a temperature sensor 8 installed on the outer casing 72 for detecting the temperature of the coolant in the interlayer 74, a first delivery pipe 11 connected to the coolant inlet on the outer casing 72, a coolant circulation pump 12 connected to the first delivery pipe 11, and a coolant storage tank 13 connected to the coolant circulation pump. An electrically controlled regulating valve 19 is installed on the connecting pipe between the coolant storage tank 13 and the coolant circulation pump 12. A PID controller for controlling the electrically controlled regulating valve is installed on the coolant storage tank 13. A second delivery pipe 14 is connected to the inlet of the coolant storage tank 13. The second delivery pipe 14 is connected to the coolant outlet on the outer casing 72. A flow meter 15 is installed on the first delivery pipe 11.

[0067] The temperature sensor 8 can monitor the temperature of the coolant in real time and transmit the detected temperature signal to the PID controller. In this embodiment, the measurement accuracy error of the temperature sensor 8 is ±0.3℃; the flow meter 15 is an electromagnetic flow meter with a measurement accuracy error of 0.3 grade; the PID controller is linked with the electric regulating valve. When the coolant temperature is higher than 5-10℃, the PID controller will control the opening of the electric regulating valve to increase the circulation rate of the coolant, thereby reducing the coolant temperature; conversely, the PID controller will control the opening of the electric regulating valve to decrease, thereby increasing the coolant temperature.

[0068] In a preferred embodiment, the outer casing 72 is further equipped with a pressure sensor 16 for detecting the internal pressure of the pipe and an exhaust valve 17 for discharging excess gas from the pipe. The exhaust valve 17 is equipped with a silencer 18. The pressure sensor 16 transmits the detected pressure value to the control system in real time. When the pressure sensor 16 detects that the internal pressure of the double-layer conveying pipe 7 exceeds a set threshold, the control system controls the opening of the exhaust valve 17 to discharge the excess gas from the pipe to the outside via the silencer 18.

[0069] The working principle of the pneumatic conveying cement cooling system for concrete mixing plants of the present invention will be explained in detail below with specific examples:

[0070] A 100KW vortex refrigeration compressor 1 is used to precisely control the temperature of the cold air at the outlet of the evaporator 4 at (8±1)℃. The refrigeration compressor 1, condenser 2, expansion valve 3, and evaporator 4 are used to generate cold air, and the fan 5 provides power for delivering the cold air.

[0071] Cold air enters the air inlet of the air-material mixing chamber 6, and cement powder enters the air-material mixing chamber 6 from the top. During the mixing process, the cold air initially cools the cement. At the same time, the cold air can also be used as a conveying power to blow the cement from the discharge port at the bottom of the air-material mixing chamber 6 through the pipeline into the double-layer conveying pipeline 7.

[0072] The inner diameter of the double-layer conveying pipe 7 is 160mm. Its inner shell 73 is made of copper-aluminum composite material with excellent thermal conductivity. The thickness of the inner shell 73 is 8.5mm, and its inner wall is machined with a spiral texture or is machined as a threaded spiral structure. Inside the inner shell 73, a set of guide plates 71 are arranged every 640mm along its length. The thickness of the guide plates 71 is 6mm, and the angle between them and the axial end face of the double-layer conveying pipe 7 is 28°. This is used to enhance the turbulence effect of cement powder flow and break the boundary layer of cement particles to enhance the heat exchange of gas-solid two-phase flow. The coolant in the jacket 74 of the double-layer conveying pipe 7 is a 40% ethylene glycol aqueous solution. The coolant temperature can be stably maintained at 6℃ and the coolant flow rate can be precisely controlled at (0.25±0.01)m³. 3 / min.

[0073] In summer conditions with an ambient temperature of 35℃, when conveying and cooling cement with an initial temperature as high as 45℃, the cement powder and 8℃ cold air are first sent into the air-material mixing chamber 6 by the power provided by the blower 5. The cement powder undergoes initial cooling upon contact with the cold air in the air-material mixing chamber 6. Then, it enters the double-layer conveying pipe 7 for thorough mixing and transmission. During transmission in the double-layer conveying pipe 7, the guide plate 71 enhances the turbulence effect of the cement powder flow and disrupts the boundary layer of cement particles to strengthen the heat exchange of the gas-solid two-phase flow, maximizing the contact area, space, and time between the cement particles and the cold air, thus achieving secondary cooling of the cement and completing efficient pre-cooling. Simultaneously with the cold air pre-cooling, the remaining heat is continuously carried away by the outer layer of coolant through the highly thermally conductive pipe wall. This process is a stable and efficient heat conduction, achieving precise and deep cooling of the cement temperature. After two stages of synergistic cooling, the cement temperature at the outlet of the double-layer conveying pipe 7 stably drops to 18℃, with a total temperature drop of up to 27℃, fully meeting the stringent requirements for raw material temperature in high-standard concrete production. During this process, the exhaust valve 17 continues to operate to ensure that there is no gas accumulation in the system, creating a stable environment for efficient heat exchange between cement and cold air.

[0074] Cement discharged from the double-layer conveying pipe 7 can be fed into the silo via a discharge device, which can be a rotary discharge valve or a double flap valve.

[0075] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A pneumatic conveying cement cooling system for a concrete mixing plant utilizing dual cold sources, characterized in that, It includes a cold air generation and conveying unit, a cement feeding mechanism, an air-material mixing chamber (6), and a double-layer conveying pipeline (7). The cold air generating and conveying unit is used to generate cold air and convey the cold air to the gas-material mixing chamber (6). The gas outlet of the cold air generating and conveying unit is connected to the air inlet of the gas-material mixing chamber (6). The cement feeding mechanism is used to store cement and transport cement to the air-material mixing chamber (6). The outlet of the cement feeding mechanism is connected to the inlet of the air-material mixing chamber (6), and the outlet of the air-material mixing chamber (6) is connected to the inlet of the double-layer conveying pipe (7). The double-layer conveying pipe (7) has a coolant in its interlayer (74) and the interlayer is connected to the external coolant circulation mechanism. Multiple sets of guide plates (71) are arranged on the inner wall of the double-layer conveying pipe (7) along its length.

2. The pneumatic conveying cement cooling system for a concrete mixing plant utilizing dual cold sources as described in claim 1, characterized in that, The cold air generation and delivery unit includes a refrigeration compressor (1), a condenser (2) connected to the refrigerant outlet of the refrigeration compressor (1) via a pipeline, an expansion valve (3) connected to the refrigerant outlet of the condenser (2) via a pipeline, an evaporator (4) connected to the refrigerant outlet of the expansion valve (3) via a pipeline, and a fan (5). The refrigerant outlet of the evaporator (4) is connected to the refrigerant inlet of the refrigeration compressor (1) via a pipeline. The outlet of the evaporator (4) is connected to a first delivery pipe, and the fan (5) is connected to a second delivery pipe. The first delivery pipe and the second delivery pipe are connected in parallel to the inlet of the gas-material mixing chamber (6).

3. The pneumatic conveying cement cooling system for a concrete mixing plant utilizing dual cold sources according to claim 1, characterized in that, The cement feeding mechanism includes a cement silo (9) and a screw feeder or rotary valve (10) for conveying cement in the cement silo (9) to the air-material mixing chamber (6).

4. The pneumatic conveying cement cooling system for a concrete mixing plant utilizing dual cold sources according to claim 1 or 3, characterized in that, The gas-material mixing chamber (6) has an inverted cone-shaped structure with a feed inlet at the top and an air inlet on the side.

5. The pneumatic conveying cement cooling system for a concrete mixing plant utilizing dual cold sources according to claim 1, characterized in that, The double-layer conveying pipe (7) includes a pipe outer shell (72) and a pipe inner shell (73) disposed inside the pipe outer shell. A jacket (74) for dispensing coolant is formed between the pipe outer shell (72) and the pipe inner shell (73). Connecting flanges are provided at both ends of the pipe outer shell (72). A coolant inlet and a coolant outlet are provided on the pipe outer shell (72). The coolant inlet and the coolant outlet are respectively connected to the two ends of the coolant circulation mechanism.

6. The pneumatic conveying cement cooling system for a concrete mixing plant utilizing dual cold sources according to claim 5, characterized in that, The coolant circulation mechanism includes a temperature sensor (8) installed on the outer casing (72) for detecting the temperature of the coolant in the interlayer (74), a first delivery pipe (11) connected to the coolant inlet on the outer casing (72), a coolant circulation pump (12) connected to the first delivery pipe (11), a coolant storage tank (13) connected to the coolant circulation pump, a second delivery pipe (14) connected to the inlet of the coolant storage tank (13), the second delivery pipe (14) connected to the coolant outlet on the outer casing (72), and a flow meter (15) installed on the first delivery pipe (11).

7. The pneumatic conveying cement cooling system for a concrete mixing plant utilizing dual cold sources according to claim 5, characterized in that, The inner wall of the inner shell (73) is also provided with a concave spiral groove or a corrugated groove.

8. The pneumatic conveying cement cooling system for a concrete mixing plant utilizing dual cold sources according to claim 1, characterized in that, The outer casing (72) of the pipe is also equipped with a pressure sensor (16) for detecting the internal pressure of the pipe and an exhaust valve (17) for venting excess gas inside the pipe. The exhaust valve (17) is equipped with a silencer (18).

9. The pneumatic conveying cement cooling system for a concrete mixing plant utilizing dual cold sources according to claim 1, characterized in that, The guide plate (71) is composed of orthogonally intersecting stainless steel plates, and there is an angle between the surface of the stainless steel plates and the axial end face of the double-layer conveying pipe (7).

10. The pneumatic conveying cement cooling system for a concrete mixing plant utilizing dual cold sources according to claim 9, characterized in that, The angle between the surface of the stainless steel plate and the axial end face of the double-layer conveying pipe (7) is 15-30°, and the distance between two adjacent sets of guide plates (71) is 3-5 times the inner diameter of the double-layer conveying pipe (7).

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