A colloid mill for cryogenic grinding

Abstract

The utility model discloses a colloid mill for low temperature grinding applied to the field of food processing, the stator is equipped with cooling cavity, the bottom of this cooling cavity sets up the liquid inlet pipe, and the upper portion sets up the liquid outlet pipe, and the outer circumferential surface of stator is equipped with spiral blade, and the cooling liquid spirally passes through the cooling cavity from bottom to top, and the cooling of stator is strengthened. On the upside and the circumferential outside of cooling cavity, there is built-in insulation layer, avoiding heat exchange with the outside world. The liquid inlet pipe and the liquid outlet pipe are preferably arranged above and below the spiral blade respectively and are tangential to the cooling cavity. For cooling the material, the liquid outlet pipe is connected to the cooling jacket arranged on the outside of the feeding hopper, and the feeding hopper is cooled. The utility model strengthens the heat exchange between the stator and the cooling liquid, and meets the temperature requirement of the material being below 60 DEG C in the grinding cavity.

Description

Technical Field

[0001] This utility model is applied in the field of food processing and relates to a colloid mill for grinding powder particles, specifically a colloid mill for low-temperature grinding. Background Technology

[0002] Colloid mills, as grinding machinery, are widely used in various industries such as food, chemical, and pharmaceutical. With their high-efficiency grinding and emulsification capabilities, large throughput, narrow particle size distribution, compact structure, simple operation, environmental friendliness and energy saving, multi-functional applications, and customized production, they have become indispensable equipment in various industries. Colloid mills are easy to install and maintain, and can perform multiple functions such as wet ultrafine grinding, pulverization, emulsification, mixing, dispersion, homogenization, and stirring. Cooling of colloid mills typically employs methods such as those shown in the attached figure. Figure 1 The cooling structure shown in CN223027394U, a colloid mill with a cooling system, involves a rotating shaft 1 driving a rotor 2 to rotate at high speed. Material 3 falling from the feed hopper 7 is subjected to shearing and frictional forces as it passes through the gap between the rotor 2 and the stator 4, achieving emulsification, dispersion, and pulverization of the material 3. This method is suitable for processing various emulsion or paste-like media. By adjusting the gap between the rotor 2 and the stator 4, a narrow particle size distribution range and high uniformity of material processing can be achieved. However, when using a colloid mill, care should be taken to avoid mixing in hard materials. Water or liquid material should remain inside the colloid mill before and after starting, stopping, and cleaning; idling and reverse rotation are prohibited. To prevent the high temperatures generated by high-speed pulverization, a cooling chamber is usually installed inside the stator 4, with cooling water flowing through the upper water pipe 6 for cooling. However, for certain special materials in the food industry, such as those used by the applicant in preparing organic selenium nutritional products, grinding and pulverization must be carried out at temperatures not exceeding 60°C; otherwise, the organic selenium will be damaged. This water-cooling method cannot meet the temperature requirements, necessitating improvements to the cooling structure.

[0003] In the area of ​​colloid mill cooling, there are numerous patent applications. For example, CN221714529U describes a colloid mill cooling system that uses a water-cooled cooling pipe to dissipate heat from the grinding mechanism. CN218250530U describes a colloid mill cooling device with a separate cooling unit, using air cooled by the cooling pipe. CN216025217U describes a colloid mill with a secondary cooling effect, using a water outlet pipe to cool the feed hopper and a fan to cool the ground material, without cooling the grinding process itself. CN214553993U describes a high-efficiency colloid mill with a cooling system where a small amount of cooling water is insufficient to cool the mill's heat. CN213376914U describes a cooling system for an emulsified asphalt colloid mill where a spiral cooling channel for cooling water is provided inside the stationary grinding discs, and a spiral cooling water pipe is fitted onto the outer surface of the grinding body. CN208960002U describes a colloid grinding system where a cooling sleeve is fitted over the return pipe. The aforementioned technical solutions or cooling methods have low heat transfer efficiency, or rely on water cooling, resulting in insufficient cooling of the grinding mechanism. CN110496672B describes a colloid mill with a cooling system, using water to cool the central sealing bearing and stationary grinding discs. Water flows through the inlet hole of the fixed seat and subsequent through-holes into the sealing cover to cool the central sealing bearing, and then flows into the grinding discs to cool the stationary grinding discs. This structure involves a tortuous water flow and requires high pressure. CN109012869A describes a self-cooling colloid mill with a cooling structure that is not substantially different from the above, except that a coolant is used instead of cooling water. Utility Model Content

[0004] The technical problem solved by this utility model is to provide a colloid mill for low-temperature grinding, which can reduce the temperature of the material in the grinding chamber to below 60°C.

[0005] The technical solution adopted in this utility model is as follows: This utility model uses a colloid mill for low-temperature grinding, which has a cooling chamber inside the stator. An inlet pipe is located at the bottom of the cooling chamber, and an outlet pipe is located at the top, allowing coolant to flow from bottom to top through the cooling chamber. Spiral blades are arranged on the outer circumferential surface of the stator within the cooling chamber to enhance stator cooling. An insulation layer is provided on the upper side and outer circumference of the cooling chamber to prevent heat exchange between the low-temperature coolant and the external environment.

[0006] Furthermore, to prevent bacterial growth, the insulation layer has an internal seal.

[0007] Furthermore, to enhance the upward spiral flow of the coolant, the inlet pipe is positioned below the spiral blades and enters the cooling chamber tangentially.

[0008] Furthermore, the outlet pipe is arranged above the spiral blade and tangentially connected to the cooling chamber. This tangential direction corresponds to the rotational direction in which the coolant enters, meaning the coolant flows out tangentially in the direction of rotation.

[0009] Furthermore, to reduce the liquid outlet resistance of the cooling chamber, the inner diameter of the liquid outlet pipe is not less than twice the inner diameter of the liquid inlet pipe.

[0010] Furthermore, to reduce the temperature of the material entering the colloid mill, the liquid outlet pipe is connected to a cooling jacket located on the outer side of the feeding hopper to cool the feeding hopper.

[0011] Furthermore, to reduce heat exchange between the coolant and the surrounding environment, a built-in sealed insulation layer is installed on the outside of the cooling jacket of the feeding hopper, and a sealing cover is placed on the feeding hopper to prevent air convection.

[0012] Furthermore, to enhance the cooling of the material, feeding pipes are evenly distributed on the sealing cover. The feeding pipes are attached to the outer circumference of the sealing cover, and the material falling from the feeding pipes can flow down the inner inclined wall of the feeding hopper to reduce the material temperature.

[0013] The beneficial effects of this invention are as follows: the positions of the inlet and outlet and the arrangement of the spiral blades enhance the heat exchange between the stator and the coolant, meeting the temperature requirement of below 60°C for organic selenium materials in the grinding chamber. Furthermore, self-cooling from the feed port enhances the low-temperature effect. Attached Figure Description

[0014] Figure 1 A schematic diagram of the main view of a colloid mill for sale; Figure 2 This is a schematic diagram of the main structure of Example 1; Figure 3 This is a schematic diagram of the main structure of Example 2; Figure 4 This is a schematic diagram of the hopper insulation in Example 2; In the diagram: 1-shaft, 2-rotor, 3-material, 4-stator, 5-cooling chamber, 6-water pipe, 7-feeding hopper, 8-liquid inlet pipe, 9-insulation layer, 10-liquid outlet pipe, 11-spiral blade, 12-cooling jacket, 13-sealing cover, 14-feeding pipe. Detailed Implementation

[0015] This utility model focuses on describing the cooling structure of the stator of the colloid mill. The transmission, sealing, and positioning structures of the colloid mill are not described in detail and are considered prior art. The internal structure of the insulation layer is only shown in the attached diagram and can be implemented based on existing mechanical structure knowledge. This utility model does not limit the use of insulation cotton or a vacuum structure for the insulation layer. Example 1

[0016] This embodiment is for the appendix Figure 1 The structure of the colloid mill, which suffers from insufficient cooling, has been improved. (Attached) Figure 1In the colloid mill, water pipe 6 is installed on the upper cover of the colloid mill, that is, on the upper part of the cooling chamber 5. The cooling water is short-circuited, only cooling the upper part of the stator 4. It is difficult to form water flow in the middle and lower parts of the cooling chamber 5, and the cooling effect can only rely on heat conduction by the stator. The middle and lower parts of the stator are often the main friction areas and the source of high temperature. In addition, the temperature of the cooling water is usually room temperature, which is small in temperature difference from the required temperature of 60°C, resulting in a small temperature gradient for heat transfer, which is not conducive to heat transfer.

[0017] The structure of this embodiment is as shown in the attached figure. Figure 2 As shown, a low-temperature coolant is used for cooling, without the use of cooling water. The temperature of the low-temperature coolant is below 0°C. The original cooling chamber 5 is enlarged to increase the flow rate of the coolant within it. The coolant inlet pipe 8 is located at the bottom of the cooling chamber 5, and the outlet pipe 10 is located at the top. The low-temperature coolant can effectively cool the lower and middle parts of the stator. After heat exchange, the coolant flows out from the top, matching the natural law of liquid thermal expansion and buoyancy. This arrangement of the inlet and outlet positions enhances the cooling of the lower and middle parts of the stator. The inlet pipe 8 and the outlet pipe 10 pass through a through hole on the outer cylinder and are threadedly sealed to the outer wall of the cooling chamber. Subsequently, the gap between the through hole and the pipe is sealed.

[0018] Inside the cooling chamber 5, spiral blades 11 are provided on the outer circumferential surface of the stator 4. The spiral blades 11 have two functions: first, to increase the heat dissipation area of ​​the stator; and second, to enhance the turbulence of the coolant, improve the heat exchange efficiency, and thus enhance the heat exchange effect between the stator and the coolant.

[0019] Because the coolant temperature is lower than room temperature, to prevent heat exchange between the coolant and the external space, insulation layers 9 are installed on the upper side and outer circumference of the cooling chamber, thus ensuring heat exchange between the coolant and the grinding chamber. To prevent bacterial growth within the gaps of the insulation layer 9, which could affect the quality of the organic selenium product, the insulation layer 9 should ideally be internally sealed. The coolant can be air conditioning refrigerant or automotive coolant, connected to an external compressor.

[0020] In this embodiment, low-temperature coolant is fed into the bottom of the cooling chamber 5 through the inlet pipe 8. The coolant rises spirally within the cooling chamber 5, making turbulent contact with the spiral blades 11 and the outer surface of the stator 4, achieving heat exchange and removing all the heat generated by the stator. The temperature of the material 3 in the grinding chamber is maintained below 60°C. After heat exchange, the coolant flows out through the outlet pipe 10 and returns to the compressor for further cooling. The built-in insulation layer 9 on the upper and outer sides of the cooling chamber prevents the low-temperature coolant from absorbing heat from the outside, ensuring heat exchange between the coolant and the stator and enhancing the cooling effect on the stator and grinding chamber.

[0021] To enhance the upward spiral flow of the coolant, the coolant in the inlet pipe 8 should ideally enter tangentially within the cooling chamber, and the coolant in the outlet pipe 10 should flow tangentially out in the direction of rotation of the cooling chamber. The inlet pipe 8 should ideally be positioned below the spiral vanes 11, and the outlet pipe 10 should ideally be positioned above the spiral vanes 11. To enhance heat exchange and reduce the resistance to coolant flow within the cooling chamber, the inner diameter of the outlet pipe 10 should not be less than twice the inner diameter of the inlet pipe 8. Example 2

[0022] This embodiment is an improvement on Embodiment 1. To further reduce the temperature during material grinding, cooling measures are added to the feeding hopper 7, as shown in the attached figure. Figure 3 As shown, the method involves reducing the temperature of the material entering the colloid mill to lower the temperature during grinding.

[0023] A sealed cooling jacket 12 is provided on the outer side of the feeding hopper 7. The inlet of the cooling jacket 12 is connected to the liquid outlet pipe 10 of the cooling chamber 5, and the outlet of the cooling jacket 12 is connected to the compressor. The low-temperature coolant enters the cooling jacket 12 after coming out of the cooling chamber, cooling the feeding hopper 7. The colloidal material flows over the inclined surface of the feeding hopper and is cooled down.

[0024] It should be noted that an insulation layer can also be provided for the feeding hopper in this embodiment, but since the hopper surface faces the outside atmosphere, providing an insulation layer is not very meaningful; it is sufficient to enhance the cooling effect of the compressor. If an internal insulation layer 9 is provided on the outside of the cooling jacket 12, it is advisable to cover the feeding hopper with a sealing cover 13, as shown in the attached figure. Figure 4 As shown, this is to avoid air convection within the feeding hopper and ensure a low temperature inside the hopper. Material flows in through multiple feeding pipes 14 on the sealing cover 13. The feeding pipes 14 are preferably evenly distributed along the outer circumference of the sealing cover 13, allowing the material to flow down the inner wall of the feeding hopper 7, thus increasing the cooling effect. In this embodiment, the cooling effect of the feeding hopper is significantly better than that of installing cooling water pipes on the outer surface of the feeding hopper, because there is no contact thermal resistance between the water pipes and the feeding hopper; the coolant directly cools the feeding hopper.

[0025] The insulation layer of this utility model is preferably made of insulation cotton. Firstly, the manufacturing and installation costs are low. Secondly, the use of sealant provides thermal resistance at the contact surface, which can slow down heat transfer.

[0026] This invention employs low-temperature coolant cooling to increase the temperature gradient for heat dissipation; it enhances heat exchange between the stator and coolant by adjusting the positions of the inlet and outlet and the arrangement of the spiral blades; it increases the space of the cooling chamber and the flow rate of the coolant; the temperature of the material in the grinding chamber depends only on the thermal conductivity of the stainless steel stator, achieving the grinding temperature requirement of below 60℃.

Claims

1. A colloidal mill for low-temperature grinding, wherein a cooling chamber is provided inside the stator, characterized in that: The bottom of the cooling chamber is provided with an inlet pipe (8) and the top is provided with an outlet pipe (10); inside the cooling chamber, the outer circumferential surface of the stator is provided with spiral blades (11); the upper side and the outer circumference of the cooling chamber are provided with a heat insulation layer (9).

2. The colloid mill for low-temperature grinding according to claim 1, characterized in that: The insulation layer (9) has an internal seal.

3. The colloid mill for low-temperature grinding according to claim 1, characterized in that: The liquid inlet pipe (8) enters the cooling chamber tangentially, and the liquid inlet pipe (8) is arranged below the spiral blade (11).

4. A colloid mill for low-temperature grinding according to claim 3, characterized in that: The outlet pipe (10) is arranged above the spiral blade (11) and is tangentially connected to the cooling chamber, the tangential direction corresponding to the rotational direction of the coolant entry.

5. A colloid mill for low-temperature grinding according to claim 1, characterized in that: The inner diameter of the outlet pipe (10) is not less than twice the inner diameter of the inlet pipe (8).

6. A colloid mill for low-temperature grinding according to claim 1, characterized in that: The liquid outlet pipe (10) is connected to the cooling jacket (12) located on the outer side of the feeding hopper.

7. A colloid mill for low-temperature grinding according to claim 6, characterized in that: The cooling jacket (12) is provided with an internally sealed heat insulation layer (9) on the outside, and the feeding hopper is covered with a sealing cover (13).

8. A colloid mill for low-temperature grinding according to claim 7, characterized in that: The sealing cap (13) is provided with a feeding tube (14), which is evenly distributed around the outer circumference of the sealing cap.

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