Polytetrafluoroethylene-coated rotors and rotor pumps

Abstract

The polytetrafluoroethylene coated rotor can ensure that the coating layer is not dissolved or swelled by the material under high temperature corrosion working condition, reduces the damage rate of the coating layer, the friction coefficient of the polytetrafluoroethylene is small, the surface of the formed coating layer is smooth, the passing rate of the material can be effectively improved, the rotor is prevented from being stuck, the rotor pump is applied to conveying lithium battery positive and negative material, the maintenance frequency of the rotor pump can be reduced, and the use reliability of the rotor pump is improved; the core rotor is provided with the engaging rod extending into the coating layer and the clamping groove for the coating layer to extend into, the engaging rod extends into the coating layer and the coating layer extends into the clamping groove, the mutual embedding combination of the coating layer and the rotor core is formed, the combination strength and the shear strength of the coating layer and the rotor core are increased, the clamping reliability of the coating layer on the rotor core is improved, the structural stability and the reliability of the rotor are improved, and the service life is prolonged.

Description

Technical Field

[0001] This invention relates to a polytetrafluoroethylene-coated rotor and a rotor pump, belonging to the field of rotor pump technology. Background Technology

[0002] Rotary lobe pumps, as a type of positive displacement pump, offer advantages such as high efficiency, low energy consumption, and minimal maintenance. The rotor is the core component of the rotary lobe pump, housed within the pump chamber with a gapless design, forming a small, sealed cavity. A pair of synchronous gears drives two rotors to rotate synchronously in opposite directions, generating continuous volume displacement. This allows the medium filling the cavity to be continuously pushed from one end to the other, achieving fluid transport. In the lithium battery industry, rotary lobe pumps play a crucial role due to their stable and efficient performance. Rotor components must meet performance requirements in terms of wear resistance, high temperature resistance, corrosion resistance, environmental friendliness and energy saving, low weight, and media purity protection to ensure the uniform transport of positive and negative electrode materials, slurries, and auxiliary materials for stable battery production. Traditional rotors are generally made of materials such as metal and ceramic. However, when conveying media with high solids content, high abrasion, and high viscosity, they are prone to wear, precipitation of undesirable impurities, poor high-temperature resistance, short service life, and difficulty in maintenance. Therefore, in the lithium industry, to ensure the purity of the positive and negative electrode materials of lithium batteries, metal rotors are generally not used. Instead, rubber rotors are used, which are metal rotor cores wrapped with a rubber sleeve. However, due to the high temperature and corrosive conditions during use, the rubber sleeve is easily dissolved or swollen by the material, causing damage to the coating, affecting material conveying, and shortening the service life of the rubber rotor. In addition, the low smoothness of the outer surface of the rubber sleeve makes it difficult for hard impurities to pass between the two rotors. In severe cases, it can cause the two rotors to jam, affecting the performance and increasing the maintenance frequency of the rotor pump. Summary of the Invention

[0003] The polytetrafluoroethylene (PTFE) coated rotor provided by this invention ensures that the coating layer will not be dissolved or swollen by materials under high-temperature and corrosive conditions, reducing the damage rate of the coating layer and effectively improving the material throughput. When applied to rotor pumps conveying positive and negative electrode materials for lithium batteries, it reduces the maintenance frequency of the rotor pump and improves its reliability. The interlocking bonding between the coating layer and the rotor core increases the bonding strength and shear strength between the coating layer and the rotor core, improves the positioning reliability of the coating layer on the rotor core, enhances the structural stability and reliability of the rotor, and extends its service life. This invention also provides a rotor pump.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A polytetrafluoroethylene (PTFE) coated rotor includes a rotor core and a coating layer covering the rotor core. The coating layer has end holes on its end face that communicate with the inner hole of the rotor core. The diameter of the end holes is larger than the inner diameter of the rotor core. The coating layer is characterized in that it is a PTFE outer layer formed by molding and sintering on the surface of the rotor core, with a thickness of 10-30 mm. The rotor core has a biting rod extending into the coating layer and a locking groove for the coating layer to extend into.

[0005] Preferably, the rotor core is in the shape of a cam rotor, having multiple spiral blades evenly distributed along a left or right helix, with the biting rod integrally formed on the end face of the spiral blades.

[0006] Preferably, each spiral blade has a biting rod on both end faces. The biting rod protrudes axially from the end face of the rotor core. The height of the biting rod is less than the thickness of the coating layer, and the diameter of the biting rod does not exceed 30 mm.

[0007] Preferably, the positioning groove is formed at the top of the spiral blade and is formed along the spiral direction of the top surface of the blade. The positioning groove is an outwardly flared arc-shaped groove.

[0008] Preferably, the end face of the rotor core has a circular protrusion, the spiral blades are evenly distributed on the outer periphery of the circular protrusion, and the inner diameter of the end face hole is smaller than the outer diameter of the circular protrusion.

[0009] Preferably, the edges and corners of the surfaces covered by the coating layer on the rotor core are rounded.

[0010] Preferably, the coating layer comprises the following components by weight: 75-80 parts polytetrafluoroethylene; 10-20 parts micron-sized silica particles; 5-10 parts micron-sized silicon nitride or silicon carbide particles; and 1-5 parts modified ceramic particles, wherein the particle size of the micron-sized silica particles, micron-sized silicon nitride or silicon carbide particles, and modified ceramic particles does not exceed 100 microns.

[0011] Preferably, the polytetrafluoroethylene is composed of a polytetrafluoroethylene suspension and polytetrafluoroethylene fine powder, wherein the mass ratio of the polytetrafluoroethylene suspension to the polytetrafluoroethylene fine powder is 20-25:70-85, and the particle size of the polytetrafluoroethylene fine powder is 500 to 600 micrometers.

[0012] Preferably, the rotor core is made of aluminum alloy, stainless steel, or ceramic.

[0013] A rotary pump, characterized in that it includes a polytetrafluoroethylene-coated rotor as described above.

[0014] The beneficial effects of this invention are: The PTFE-coated rotor of this invention has a PTFE outer layer formed by molding and sintering on the surface of the rotor core. PTFE has corrosion resistance and high temperature resistance, ensuring that the PTFE layer will not be dissolved or swollen by materials under high-temperature corrosive conditions, reducing the damage rate of the PTFE layer. Moreover, PTFE has a low coefficient of friction, resulting in a smooth surface of the PTFE layer, which can effectively improve the material throughput, prevent the rotor from jamming, and improve transmission reliability. Applying the PTFE-coated rotor to a rotor pump for conveying positive and negative electrode materials of lithium batteries can reduce the maintenance frequency of the rotor pump and improve its reliability. The rotor core has a biting rod extending into the PTFE layer and a locking groove for the PTFE layer to extend into. The biting rod extending into the PTFE layer and the PTFE layer extending into the locking groove form an interlocking bond between the PTFE layer and the rotor core, increasing the bonding strength and shear strength between the PTFE layer and the rotor core, improving the locking reliability of the PTFE layer on the rotor core, improving the structural stability and reliability of the rotor, and extending its service life. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the polytetrafluoroethylene-coated rotor of the present invention.

[0016] Figure 2 This is a schematic diagram of the rotor core.

[0017] Figure 3 This is another schematic diagram of the rotor core.

[0018] Figure 4 This is a cross-sectional view of the polytetrafluoroethylene-coated rotor of the present invention. Detailed Implementation

[0019] The following is combined Figures 1-4 The embodiments of the present invention will be described in detail below.

[0020] A polytetrafluoroethylene (PTFE) coated rotor includes a rotor core 1 and a coating layer 2 covering the rotor core 1. The coating layer 2 has an end hole 21 on its end face that communicates with the inner hole of the rotor core 1. The diameter of the end hole 21 is larger than the inner diameter of the rotor core. The coating layer 2 is a PTFE outer layer formed by molding and sintering on the surface of the rotor core 1, with a thickness of 10-30 mm. The rotor core 1 has an engagement rod 11 extending into the coating layer 2 and a positioning groove 12 for the coating layer 2 to extend into.

[0021] The PTFE-coated rotor described above has a coating layer 2 formed by molding and sintering onto the surface of the rotor core 1. PTFE has corrosion resistance and high-temperature resistance, ensuring that the coating layer 2 will not dissolve or swell under high-temperature corrosive conditions, reducing the damage rate of the coating layer 2. Furthermore, PTFE has a low coefficient of friction, resulting in a smooth coating layer surface, which effectively improves material throughput, prevents rotor jamming, and enhances transmission reliability. This PTFE-coated rotor can be applied to rotors used for conveying positive and negative electrode materials from lithium batteries. In the pump, the maintenance frequency of the rotor pump can be reduced and the reliability of the rotor pump can be improved. The core rotor 1 has a biting rod 11 that extends into the coating layer 2 and a locking groove 12 for the coating layer 2 to extend into. By the biting rod 11 extending into the coating layer 2 and the coating layer 2 extending into the locking groove 12, the coating layer 2 and the rotor core 1 are mutually embedded and combined, which increases the bonding strength and shear strength between the coating layer 2 and the rotor core 1, improves the locking reliability of the coating layer on the rotor core, improves the structural stability and reliability of the rotor, and extends its service life.

[0022] The rotor core 1 is shaped like a cam rotor, with multiple spiral blades 13 evenly distributed along a left-hand or right-hand helix. Engaging rods 11 are integrally formed on the end faces of the spiral blades 13. As shown in the attached figure, the rotor core 1 is a three-lobe cam rotor shape, with three spiral blades 13 evenly distributed along a right-hand helix. The end faces of the spiral blades 13 have engaging rods. The engaging rods 11 extend into the covering layer 2 and are completely covered by the covering layer 2. The engaging rods 11 increase the bonding strength and shear resistance between the covering layer 2 and the rotor core 1, enabling the covering layer 2 and the rotor core 1 to form a stable whole, effectively preventing the covering layer 2 from moving on the rotor core 1 during rotor operation.

[0023] Each helical blade 13 has a biting rod 11 on both end faces. The biting rod 11 protrudes axially from the end face of the rotor core. The height of the biting rod 11 is less than the thickness of the covering layer 2, and the diameter of the biting rod 11 does not exceed 30 mm. Figure 3 As shown, each of the two end faces of the helical blade 13 has an axially protruding biting rod 11. The three helical blades 13 have a total of six biting rods 11. The biting rods 11 extend into the coating layer 2, ensuring that the corresponding positions of the coating layer 2 and the helical blades 13 are evenly stressed, further improving the overall structural stability of the coating layer 2 and the rotor core 1. The diameter of the biting rod does not exceed 30 mm, and its height is less than the thickness of the coating layer 2, ensuring that the biting rod 11 is completely covered by the coating layer 2 and preventing cracking of the coating layer 2 due to the biting rod 11 extending into it.

[0024] The locking groove 12 is located at the tip of the spiral blade 13 and follows the spiral direction of the blade tip. The locking groove 12 is an outwardly flared arc-shaped groove. When the rotor rotates and extrudes material, the tip of the spiral blade 13 experiences the greatest force. By positioning the locking groove 12 at the blade tip and extending the coating layer 2 into it, the locking effect of the coating layer 2 at the blade tip is enhanced. This strengthens the bond between the coating layer 2 and the rotor core 1 at the top of the spiral blade, ensuring that the coating layer 2 will not shift due to excessive force during rotor rotation, thus improving the structural stability and reliability of the PTFE-coated rotor. The locking groove 12 follows the spiral direction of the blade tip, ensuring that its placement does not affect the spiral shape of the spiral blade 13. This results in the PTFE-coated rotor formed by the coating layer 2 covering the rotor core 1 having a smooth, regular spiral cam shape, ensuring reliable transmission.

[0025] The rotor core 1 has a circular protrusion 14 on its end face, and spiral blades 13 are evenly distributed around the outer periphery of the circular protrusion 14. The inner diameter of the end face hole 21 is smaller than the outer diameter of the circular protrusion 14. The inner diameter of the rotor core 1 is the same as the inner diameter of the rotor core 1. The inner hole of the rotor core 1 has a keyway that mates with the motor shaft. The end face hole 21 is larger than the inner diameter of the rotor core 1 to prevent interference between the motor shaft and the covering layer 2 when the motor shaft extends into the inner hole of the rotor core to form a keyway. The circular protrusion 14 on the end face of the rotor core 1, with the inner diameter of the end face hole 21 being smaller than the outer diameter of the circular protrusion 14, extends the covering layer 2 onto the circular protrusion 14. A countersunk surface that mates with the circular protrusion 14 is formed on the inner wall of the covering layer 2, achieving radial positioning of the covering layer 2 on the rotor core 1, further improving the positioning effect of the covering layer 2 on the rotor core 1, and further improving the overall structural stability of the covering layer 2 and the rotor core 1.

[0026] In this design, the edges and corners of the rotor core 1 covered by the coating layer 2 are all rounded. This avoids stress concentration at sharp angles and prevents the outer coating layer 2 from cracking during molding, thus improving the molding effect and quality of the coating layer 2.

[0027] The coating layer comprises the following components by weight: 75-80 parts polytetrafluoroethylene (PTFE); 10-20 parts micron-sized silica particles; 5-10 parts micron-sized silicon nitride or silicon carbide particles; and 1-5 parts modified ceramic particles. The particle size of the micron-sized silica particles, silicon nitride or silicon carbide particles, and modified ceramic particles does not exceed 100 microns. PTFE and filler particles are used as raw materials and sintered onto the rotor core 1 by molding to form a PTFE outer layer, i.e., the coating layer 2. The micron-sized silica particles, silicon nitride or silicon carbide particles, and modified ceramic particles serve as filler particles, enhancing performance, improving the wear resistance, mechanical strength, and thermal conductivity of the coating layer 2, and extending its service life.

[0028] The polytetrafluoroethylene (PTFE) is composed of a PTFE suspension and fine PTFE powder, with a mass ratio of 20-25:70-85. The particle size of the PTFE powder is 500 to 600 micrometers. PTFE is formed by mixing the PTFE suspension and the fine powder. The extremely small particle size of the PTFE particles in the PTFE suspension allows for uniform mixing with the PTFE powder and filler particles, ensuring a more uniform density coating layer 2 during molding and sintering, thus improving the molding quality of the coating layer 2.

[0029] The rotor core 1 is made of aluminum alloy, stainless steel, or ceramic. The rotor core 1 has excellent strength, providing effective internal support for the cladding layer 2 and improving the overall strength of the PTFE-clad rotor.

[0030] This invention also protects a rotary pump, characterized by comprising the polytetrafluoroethylene (PTFE) coated rotor described above. The PTFE-coated rotor described above can reduce the maintenance frequency of the rotary pump, improve its reliability, and extend its service life.

[0031] The technical solutions of the embodiments of the present invention have been fully described above with reference to the accompanying drawings. It should be noted that the described embodiments are only a part of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

Claims

1. A polytetrafluoroethylene (PTFE) coated rotor, comprising a rotor core and a coating layer covering the rotor core, wherein an end hole communicating with an inner hole of the rotor core is formed on the end face of the coating layer, and the diameter of the end hole is larger than the inner diameter of the rotor core, characterized in that, The coating layer is a polytetrafluoroethylene outer layer formed by molding and sintering on the surface of the rotor core, with a thickness of 10-30 mm. The rotor core has a biting rod extending into the coating layer and a locking groove for the coating layer to extend into.

2. The polytetrafluoroethylene-coated rotor according to claim 1, characterized in that, The rotor core is shaped like a cam rotor and has multiple spiral blades evenly distributed along a left or right helix. The biting rod is integrally formed on the end face of the spiral blades.

3. The polytetrafluoroethylene-coated rotor according to claim 2, characterized in that, Each spiral blade has a biting rod on both ends. The biting rod protrudes axially from the end face of the rotor core. The height of the biting rod is less than the thickness of the coating layer, and the diameter of the biting rod does not exceed 30 mm.

4. The polytetrafluoroethylene-coated rotor according to claim 2, characterized in that, The positioning groove is formed at the top of the spiral blade and follows the spiral direction of the top surface of the blade. The positioning groove is an outwardly flared arc-shaped groove.

5. The polytetrafluoroethylene-coated rotor according to claim 2, characterized in that, The end face of the rotor core has a circular protrusion, and the spiral blades are evenly distributed on the outer periphery of the circular protrusion. The inner diameter of the end face hole is smaller than the outer diameter of the circular protrusion.

6. The polytetrafluoroethylene-coated rotor according to claim 1, characterized in that, All edges and corners of the rotor core covered by the coating layer are rounded.

7. The polytetrafluoroethylene-coated rotor according to claim 1, characterized in that, The coating layer comprises the following components by weight: 75-80 parts polytetrafluoroethylene; 10-20 parts micron-sized silica particles; and 5-10 parts micron-sized silicon nitride or silicon carbide particles. 1-5 parts of modified ceramic microparticles, the particle size of which is no more than 100 micrometers, including micron-sized silica microparticles, micron-sized silicon nitride or silicon carbide microparticles, and modified ceramic microparticles.

8. The polytetrafluoroethylene-coated rotor according to claim 7, characterized in that, Polytetrafluoroethylene (PTFE) is composed of PTFE suspension and PTFE fine powder. The mass ratio of PTFE suspension to PTFE fine powder is 20-25:70-85, and the particle size of PTFE fine powder is 500 to 600 micrometers.

9. The polytetrafluoroethylene-coated rotor according to claim 1, wherein the rotor core is made of aluminum alloy, stainless steel or ceramic.

10. A rotary pump, characterized in that, Includes the polytetrafluoroethylene-coated rotor as described in any one of claims 1 to 9.

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