A port crane inverter protection cabinet

Abstract

The present invention relates to the technical field of electric power facilities, and in particular to a port crane inverter protection cabinet, comprising a cabinet body and a cabinet door, wherein the cabinet body is movably connected to the cabinet door through a hinge, the cabinet door and the cabinet body are respectively made of modified polycarbonate injection molding, a stainless steel frame is provided in the inner cavity of the cabinet, and the inner cavity surface of the cabinet and the surface of the stainless steel frame are covered with functional coating to form a shielding layer. The present invention uses modified polycarbonate injection molding to make the cabinet body and the cabinet door, so that the cabinet body has good electromagnetic shielding function while achieving lightweight of the port crane inverter protection cabinet.

Description

Technical Field

[0001] The invention relates to the technical field of electric power facilities, and in particular to a frequency converter protection cabinet for a port crane. Background Art

[0002] The frequency converter is a power control device that uses frequency conversion technology and microelectronics technology to control the AC motor by changing the frequency of the motor's working power supply. The working principle of the frequency converter is to convert AC power into DC power through a rectifier, and then convert DC power into AC power with adjustable frequency and voltage through an inverter, thereby controlling the operation of the motor. The frequency converter can be used to realize soft starting, variable frequency speed regulation, improve operation accuracy, change power factor, overcurrent / overvoltage / overload protection and other functions of AC asynchronous motors. With the continuous improvement of industrial automation, frequency converters are widely used in industrial automation, household appliances, computer power supplies and other fields.

[0003] In the modern industrial field, cranes are indispensable heavy equipment, and their performance and efficiency are directly related to the smooth operation of the production line and cost control. Cranes often need to start and stop in the process of lifting goods. Traditional cranes are prone to impact during the start and stop process, causing unnecessary damage to goods and mechanical equipment. Installing a frequency converter on the crane can make the crane run more smoothly through precise start and stop control, reduce the impact during the start and stop process, and extend the service life of the crane. The operating environment of the port has the characteristics of large vibration and impact, severe dust, high humidity, and high corrosion components such as salt and alkali. The existing technology usually sets the port crane frequency converter in a protective cabinet made of stainless steel or aluminum alloy for protection. The stainless steel control cabinet has good corrosion resistance and impact resistance, but the production cost is high and the weight is large, which is not conducive to movement and installation; the aluminum alloy control cabinet is light in weight, but it needs to be processed by special processes such as extrusion and stretching, and the machinability is poor. Summary of the invention

[0004] In view of the problem that port crane inverter protection cabinets made of stainless steel or aluminum alloy are heavy and have poor machinability, the present invention provides a port crane inverter protection cabinet, in which a cabinet body and a cabinet door are made by injection molding of modified polycarbonate, so that the port crane inverter protection cabinet is lightweight and the cabinet body has good electromagnetic shielding function.

[0005] The technical solution of the present invention is as follows: A port crane inverter protection cabinet comprises a cabinet body and a cabinet door, wherein the cabinet body is movably connected to the cabinet door through hinges, the cabinet door and the cabinet body are respectively made of modified polycarbonate injection molding, a stainless steel frame is provided in the inner cavity of the cabinet, and a functional coating is covered on the inner cavity surface of the cabinet and the surface of the stainless steel frame to form a shielding layer; The modified polycarbonate comprises the following components: 70-85 parts by weight of polycarbonate, 30-40 parts by weight of polybutylene terephthalate and 1-3 parts by weight of glass fiber; The functional coating comprises polyvinyl butyral and carbon nanotubes, the mass ratio of the carbon nanotubes to the polyvinyl butyral is 1:1-3, and the thickness of the shielding layer is 0.5-3mm.

[0006] Furthermore, the stainless steel frame of the inner cavity of the cabinet is a rectangular parallelepiped structure, and the inner cavity of the cabinet is fixed to the outer facade of the stainless steel frame. The cabinet body groove and the cabinet door groove are respectively provided on the end surface opposite to the cabinet body, and the cabinet body groove and the cabinet door groove are both embedded with sealing strips. When the cabinet door is closed, the sealing strips in the cabinet body groove and the sealing strips in the cabinet door groove contact each other, and the sealing performance is good.

[0007] Furthermore, the inner side of the cabinet door is provided with reinforcing ribs, the material of the reinforcing ribs is preferably stainless steel or aluminum alloy, and the reinforcing ribs are parallel to the inner edge of the cabinet door. The inner surface of the cabinet door and the surface of the reinforcing ribs can also be covered with functional coatings to form a shielding layer.

[0008] Furthermore, the polycarbonate is a linear polycarbonate with a weight average molecular weight of 30,000-50,000; the glass fiber is an alkali-free short glass fiber; and the carbon nanotube is a multi-walled carbon nanotube.

[0009] Furthermore, the preparation method of the modified polycarbonate comprises the following steps: Step 1: activating, separating, washing and drying the glass fibers in sequence to obtain activated glass fibers; Step 2: uniformly mixing the dried polycarbonate and the dried polybutylene terephthalate and heating and melting them to obtain a molten mixture; Step 3: Add the activated glass fiber obtained in step 1 to the molten mixture, mix well, and then extrude and granulate to obtain modified polycarbonate.

[0010] Furthermore, in step one, the activation treatment is to use a coupling agent solution for surface pretreatment, the coupling agent solution is preferably an ethanol solution of a silane coupling agent with a concentration of 16wt%-26wt%, the surface pretreatment time is 20-60min, the surface pretreatment temperature is 20-30°C, and the surface pretreatment is carried out under ultrasound or stirring.

[0011] Furthermore, the temperature of injection molding is 270-300°C.

[0012] Furthermore, the preparation method of the functional coating comprises the following steps: Step 1: adding carbon nanotubes to ethanol and dispersing them ultrasonically to prepare a carbon nanotube ethanol dispersion having a concentration of 7wt%-9wt%; Step 2: Add polyvinyl butyral to the carbon nanotube ethanol dispersion, stir at 55-65° C. for 0.5-1 h to obtain a functional coating.

[0013] Furthermore, after the functional coating is applied to the inner surface of the cabinet body and the surface of the stainless steel frame, it is dried at 40-50° C. to form a shielding layer.

[0014] The beneficial effects of the present invention are: The port crane inverter protection cabinet provided by the present invention uses modified polycarbonate to make a cabinet body and a cabinet door by injection molding. The modified polycarbonate is selected as the processing raw material, which not only effectively reduces the weight of the cabinet body and the cabinet door, but also improves the insulation of the cabinet body and the cabinet door, and gives the cabinet body and the cabinet door a certain light transmittance, which is conducive to real-time observation of the working conditions of the components in the port crane inverter protection cabinet; the cabinet body and the cabinet door are prepared by injection molding, which has high material utilization and great design flexibility, and can also improve the dimensional accuracy of the cabinet body and the cabinet door; a stainless steel frame is arranged in the inner cavity of the cabinet to improve the structural strength of the cabinet; the present invention also forms a shielding layer by covering the inner cavity surface of the cabinet and the surface of the stainless steel frame with functional coating, so that the cabinet has good electromagnetic shielding function. DETAILED DESCRIPTION

[0015] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0016] Example 1 A port crane inverter protection cabinet includes a cabinet body and a cabinet door. The cabinet body is movably connected to the cabinet door through hinges. The cabinet door and the cabinet body are respectively made of modified polycarbonate injection molding at 270°C. The inner cavity of the cabinet is provided with a stainless steel frame of a rectangular structure, and the inner cavity of the cabinet is fixed to the outer facade of the stainless steel frame. After the inner cavity surface of the cabinet and the surface of the stainless steel frame are covered with functional coating, they are dried at 40°C to form a shielding layer, and the thickness of the shielding layer is 0.5mm. Cabinet body grooves and cabinet door grooves are respectively provided around the end faces opposite to the cabinet door. The cabinet body grooves and cabinet door grooves are both embedded with high-level sealing strips. When the cabinet door is closed, the sealing strips in the cabinet body grooves and the sealing strips in the cabinet door grooves are in contact with each other, and the sealing performance is good. The inner side of the cabinet door is provided with a rectangular reinforcing rib made of stainless steel.

[0017] Wherein, the preparation method of modified polycarbonate comprises the following steps: Step 1: Wash and dry the alkali-free short glass fibers, then soak the dried alkali-free short glass fibers in a 16wt% ethoxysilane ethanol solution, stir and react at 30°C for 40 minutes, then filter, wash and dry in sequence to obtain activated glass fibers.

[0018] Step 2: 85 parts by weight of dry polycarbonate and 30 parts by weight of dry polybutylene terephthalate are mixed evenly and heated to melt to obtain a molten mixture. The polycarbonate is a linear polycarbonate with a weight average molecular weight of 30,000.

[0019] Step 3: Add the molten mixture into a twin-screw extruder from the upper feed port, add 1 part by weight of the activated glass fiber obtained in step 1 into the twin-screw extruder from the side feeder, mix the molten mixture and the activated glass fiber in the twin-screw extruder evenly, and then extrude and granulate to obtain modified polycarbonate. The extrusion temperature of the twin-screw extruder is 260° C., and the screw speed is 550 rpm.

[0020] The preparation method of the functional coating comprises the following steps: Step 1: Add multi-walled carbon nanotubes into ethanol and disperse them by ultrasonic to prepare a carbon nanotube ethanol dispersion with a concentration of 9 wt%.

[0021] Step 2: Add polyvinyl butyral to the carbon nanotube ethanol dispersion, stir at 55° C. for 0.5 h, and obtain a functional coating. The mass ratio of multi-walled carbon nanotubes to polyvinyl butyral is 1:1.

[0022] Example 2 A port crane inverter protection cabinet includes a cabinet body and a cabinet door. The cabinet body is movably connected to the cabinet door through hinges. The cabinet door and the cabinet body are respectively made of modified polycarbonate injection molding at 300°C. The inner cavity of the cabinet is provided with a stainless steel frame of a rectangular structure, and the inner cavity of the cabinet is fixed to the outer facade of the stainless steel frame. After the inner cavity surface of the cabinet and the surface of the stainless steel frame are covered with functional coating, they are dried at 45°C to form a shielding layer, and the thickness of the shielding layer is 2.1mm. Cabinet grooves and cabinet door grooves are respectively provided around the end faces opposite to the cabinet door. High-level sealing strips are embedded in the cabinet grooves and cabinet door grooves. When the cabinet door is closed, the sealing strips in the cabinet grooves and the sealing strips in the cabinet door grooves are in contact with each other, and the sealing performance is good. Rectangular reinforcing ribs made of stainless steel are provided on the inner side of the cabinet door.

[0023] Wherein, the preparation method of modified polycarbonate comprises the following steps: Step 1: Clean and dry the alkali-free short glass fibers, then soak the dried alkali-free short glass fibers in a 20wt% ethoxysilane ethanol solution, subject them to ultrasonic reaction at 26°C for 50 minutes, and then filter, wash and dry them in sequence to obtain activated glass fibers.

[0024] Step 2: Mix 70 parts by weight of dry polycarbonate and 40 parts by weight of dry polybutylene terephthalate evenly, and heat to melt to obtain a molten mixture. The polycarbonate is a linear polycarbonate with a weight average molecular weight of 35,000.

[0025] Step 3: Add the molten mixture into a twin-screw extruder from the upper feed port, add 2 parts by weight of the activated glass fiber obtained in step 1 into the twin-screw extruder from the side feeder, mix the molten mixture and the activated glass fiber in the twin-screw extruder evenly, and then extrude and granulate to obtain modified polycarbonate. The extrusion temperature of the twin-screw extruder is 250° C., and the screw speed is 500 rpm.

[0026] The preparation method of the functional coating comprises the following steps: Step 1: Add multi-walled carbon nanotubes into ethanol and disperse them by ultrasonication to prepare a carbon nanotube ethanol dispersion with a concentration of 7 wt %.

[0027] Step 2: Add polyvinyl butyral to the carbon nanotube ethanol dispersion, stir at 60° C. for 1 hour to obtain a functional coating. The mass ratio of multi-walled carbon nanotubes to polyvinyl butyral is 1:1.5.

[0028] Example 3 A port crane inverter protection cabinet includes a cabinet body and a cabinet door. The cabinet body is movably connected to the cabinet door through hinges. The cabinet door and the cabinet body are respectively made of modified polycarbonate by injection molding at 280°C. The inner cavity of the cabinet is provided with a stainless steel frame of a rectangular structure, and the inner cavity of the cabinet is fixed to the outer facade of the stainless steel frame. After the inner cavity surface of the cabinet and the surface of the stainless steel frame are covered with functional coating, they are dried at 50°C to form a shielding layer, and the thickness of the shielding layer is 3mm. Cabinet body grooves and cabinet door grooves are respectively provided around the end faces opposite to the cabinet door. The cabinet body grooves and cabinet door grooves are both embedded with high-level sealing strips. When the cabinet door is closed, the sealing strips in the cabinet body grooves and the sealing strips in the cabinet door grooves are in contact with each other, and the sealing performance is good. The inner side of the cabinet door is provided with a rectangular reinforcing rib made of stainless steel.

[0029] Wherein, the preparation method of modified polycarbonate comprises the following steps: Step 1: Wash and dry the alkali-free short glass fibers, then soak the dried alkali-free short glass fibers in a 26wt% ethoxysilane ethanol solution, stir and react at 20°C for 60 minutes, then filter, wash and dry in sequence to obtain activated glass fibers.

[0030] Step 2: Mix 78 parts by weight of dry polycarbonate and 36 parts by weight of dry polybutylene terephthalate evenly, and heat to melt to obtain a molten mixture. The polycarbonate is a linear polycarbonate with a weight average molecular weight of 40,000.

[0031] Step 3: Add the molten mixture into a twin-screw extruder from the upper feed port, add 3 parts by weight of the activated glass fiber obtained in step 1 into the twin-screw extruder from the side feeder, mix the molten mixture and the activated glass fiber in the twin-screw extruder evenly, and then extrude and granulate to obtain modified polycarbonate. The extrusion temperature of the twin-screw extruder is 250° C., and the screw speed is 520 rpm.

[0032] The preparation method of the functional coating comprises the following steps: Step 1: Add multi-walled carbon nanotubes into ethanol and disperse them by ultrasonication to prepare a carbon nanotube ethanol dispersion with a concentration of 8 wt %.

[0033] Step 2: Add polyvinyl butyral to the carbon nanotube ethanol dispersion, stir at 65° C. for 40 minutes to obtain a functional coating. The mass ratio of multi-walled carbon nanotubes to polyvinyl butyral is 1:3.

[0034] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is only in the preparation method of the modified polycarbonate. Step 2: 85 parts by weight of dry polycarbonate and 20 parts by weight of dry polybutylene terephthalate are mixed evenly and then heated to melt to obtain a molten mixture.

[0035] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the modified polycarbonate does not contain glass fiber.

[0036] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that in the preparation method of the functional coating, the mass ratio of multi-walled carbon nanotubes to polyvinyl butyral is 3:1.

[0037] The protection level, mechanical collision protection level, electromagnetic shielding performance of the shielding layer and transparency of the cabinet door of the port crane inverter protection cabinet in Examples 1 to 3 and Comparative Examples 1 to 3 were tested respectively, and the test results are shown in Table 1. As can be seen from Table 1, the protection level of the port crane inverter protection cabinet prepared in Examples 1 to 3 is IP65, and has good waterproof and dustproof performance; the mechanical collision protection level of the port crane inverter protection cabinet prepared in Examples 1 to 3 reaches IK10, and has high impact strength. Compared with Comparative Examples 1 to 3, the port crane inverter protection cabinet prepared in Example 1 not only has a higher protection level and mechanical collision protection level, but also has good cabinet door transparency and electromagnetic shielding performance.

[0038] Table 1 Performance test results of the port crane inverter protection cabinet in Example 1-Example 3 and Comparative Example 1-Comparative Example 3

[0039] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily conceive of changes or substitutions within the technical scope disclosed by the present invention, and such changes or substitutions shall be within the scope of protection of the present invention.

Claims

1. A port crane inverter protection cabinet, comprising a cabinet body and a cabinet door, characterized in that: The cabinet body is movably connected to the cabinet door through hinges. The cabinet door and the cabinet body are respectively made of modified polycarbonate injection molding. A stainless steel frame is provided in the inner cavity of the cabinet. The inner cavity surface of the cabinet and the surface of the stainless steel frame are covered with functional coating to form a shielding layer. The modified polycarbonate comprises the following components: 70-85 parts by weight of polycarbonate, 30-40 parts by weight of polybutylene terephthalate and 1-3 parts by weight of glass fiber; The functional coating comprises polyvinyl butyral and carbon nanotubes, the mass ratio of the carbon nanotubes to the polyvinyl butyral is 1:1-3, and the thickness of the shielding layer is 0.5-3mm.

2. A port crane inverter protection cabinet as claimed in claim 1, characterized in that: The stainless steel frame of the cabinet interior is a rectangular structure.

3. A port crane inverter protection cabinet as claimed in claim 1, characterized in that: The inner side of the cabinet door is provided with reinforcing ribs.

4. A port crane inverter protection cabinet as claimed in claim 1, characterized in that: The polycarbonate is a linear polycarbonate with a weight average molecular weight of 30000-50000; the glass fiber is an alkali-free short glass fiber; and the carbon nanotube is a multi-walled carbon nanotube.

5. A port crane inverter protection cabinet as claimed in claim 1, characterized in that: The preparation method of modified polycarbonate comprises the following steps: Step 1: activating, separating, washing and drying the glass fibers in sequence to obtain activated glass fibers; Step 2: uniformly mixing the dried polycarbonate and the dried polybutylene terephthalate and heating and melting them to obtain a molten mixture; Step 3: Add the activated glass fiber obtained in step 1 to the molten mixture, mix well, and extrude and granulate to obtain modified polycarbonate.

6. A port crane inverter protection cabinet as claimed in claim 5, characterized in that: In step 1, the activation treatment is to use a coupling agent solution for surface pretreatment.

7. A port crane inverter protection cabinet as claimed in claim 1, characterized in that: The temperature of injection molding is 270-300℃.

8. A port crane inverter protection cabinet as claimed in claim 1, characterized in that: The preparation method of the functional coating comprises the following steps: Step 1: adding carbon nanotubes to ethanol and dispersing them ultrasonically to prepare a carbon nanotube ethanol dispersion having a concentration of 7wt%-9wt%; Step 2: Add polyvinyl butyral to the carbon nanotube ethanol dispersion, stir at 55-65° C. for 0.5-1 h to obtain a functional coating.

9. A port crane inverter protection cabinet as claimed in claim 1, characterized in that: After the functional coating is applied to the inner surface of the cabinet body and the surface of the stainless steel frame, it is dried at 40-50°C to form a shielding layer.

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