Mining individual protection power air supply explosion-proof miniature fan

Abstract

The invention relates to a mining individual protection power air supply explosion-proof miniature fan which is characterized by comprising a volute front cover (1), a motor shell (3), two fan shaft sleeves (4), an impeller assembly (5), a magnet sleeve (6), a motor shaft (7), a stator coil (13), an impeller fixing disc (8), a fan base (9) and a volute rear cover (10) which are connected together. The impeller combination (5), the stator coil (13), the magnet sleeve (6) and the motor shaft (7) are all designed in the same space, namely, the motor shaft (7) is the axis of the impeller combination (5), the stator coil (13) and the magnet sleeve (6), so that the size and the weight of the motor are greatly reduced, the motor can be matched with the mining power air supply system for use, and the mining power air supply system is very light.

Description

Technical Field

[0001] This invention relates to the technical field of mine safety equipment, specifically a miniature powered air supply unit with intrinsically safe explosion-proof design. It is suitable for use in mine environments where explosive gases such as methane and coal dust are present. The unit integrates a low-energy drive system, a high-efficiency impeller structure, and explosion-proof packaging technology, achieving both miniaturization and intrinsic safety for individual respiratory protection equipment used in mines. Background Art

[0002] As mining activities deepen, underground working environments become increasingly complex, placing higher demands on the performance and safety of mining equipment. According to GB 3836.1-2021, General Requirements for Equipment for Explosive Atmospheres, mining respiratory equipment must meet the following requirements: explosion-proof types that meet standard specifications; electrical equipment must ensure that circuit design meets explosion-proof requirements; possess sufficient mechanical strength and corrosion resistance; and avoid the use of materials that are prone to sparking; enclosures must meet IP54 or higher protection levels (dustproof and waterproof) to prevent the intrusion of combustible dust or gas; joint surface clearances and thread parameters must meet explosion-proof requirements to ensure that internal explosions do not ignite the external environment; non-metallic components must be treated with antistatic treatment to prevent static electricity accumulation; the materials and structure of breathing valves and filters must avoid generating static electricity or sparks; and airflow resistance must meet ergonomic requirements (refer to GB 2626, "Respiratory Protective Equipment"). Mining powered air blowers, as crucial equipment for ensuring the respiratory safety of underground mine workers, must possess national explosion-proof certification and obtain an explosion-proof certificate.

[0003] According to data released by market research firm Grand View Research 2022, the current global market size of personal protective equipment for mining is estimated to be around 4-5 billion yuan, and is showing an increasing trend year by year. However, respiratory protection equipment (such as mining self-rescuers and filtering respirators) is the core demand, with an annual growth rate of about 4%-6%, and there is a huge market gap.

[0004] Underground mines often contain high concentrations of dust and explosive gases. On the one hand, inhaling large amounts of dust can lead to health problems such as pneumoconiosis among workers. On the other hand, explosive gases can easily cause explosions if they encounter a fire source, seriously threatening the lives of miners. This requires fans to have efficient filtration capabilities and strict explosion-proof designs. By installing high-efficiency filters, fans can effectively remove dust particles from the air, ensuring that workers breathe clean air. Furthermore, the explosion-proof design prevents fans from generating sparks or high temperatures in explosive environments, potentially leading to explosions.

[0005] Furthermore, powered ventilation fans for mines must possess sufficient air supply capacity and stability. During underground mining operations, workers require an adequate supply of dust-free or low-pollution oxygen to maintain normal breathing. According to ergonomic and physiological research, adult males performing moderate-intensity underground mining work require approximately 60-100 liters of fresh air per minute. This requires fans to provide sufficient air supply. Furthermore, due to the complex and variable underground mining environment, characterized by significant fluctuations in temperature, humidity, and air pressure, as well as interference factors such as mechanical vibration, fans must also be able to operate stably under these harsh conditions to ensure workers' respiratory safety.

[0006] However, currently, powered air supply micro-blowers for personal protection in mines are almost scarce on the market. In particular, products that can simultaneously meet the special environmental requirements of underground mines in terms of explosion-proof performance, filtration efficiency, and air supply capacity are even rarer. Given the complexity and danger of the underground working environment, the respiratory safety of miners is particularly critical. Therefore, the goal of this patent is to break through technical barriers and develop an efficient, safe, and reliable powered air supply explosion-proof micro-blower for mining through innovative design and technical optimization, providing strong respiratory safety protection for underground mine workers and filling the market gap in this field. Summary of the Invention

[0007] The present invention provides a mine-used powered air supply explosion-proof micro fan, which is used in conjunction with individual protective filtering and air supply equipment to provide miners with the clean air they need to breathe.

[0008] A mine-use personal protective power air supply explosion-proof micro fan, characterized in that it comprises a volute front cover 1, a motor housing 3, two fan sleeves 4, an impeller assembly 5, a magnet sleeve 6, a motor shaft 7, a stator coil 13, an impeller fixing disc 8, a fan base 9 and a volute rear cover 10 connected together; characterized in that the fan base 9 is fixedly mounted on the volute rear cover 10, the motor housing 3 is installed on the outer wall of the magnet sleeve 6 with an interference fit, the upper end of the motor shaft 7 is fixedly mounted in the center hole of the upper end face of the motor housing 3 by nuts and bolts, the stator coil 13 is between the magnet sleeve 6 and the motor shaft 7, and the upper part of the motor shaft 7 is connected to the On the inner wall of the center hole of the stator coil 13, the lower end of the motor shaft 7 is installed on the center hole of the fan base 9 through the fan sleeve 4; the bottom of the stator coil 13 is fixed to the upper surface of the fan base 9; the motor housing 3, which is interference fit with the magnet sleeve 6, is also connected to the impeller assembly 5 through interference fit, and the large hole in the center of the impeller fixing disc 8 is sleeved on the outer wall of the motor housing 3. At the same time, the impeller fixing disc 8 is fixedly connected to the lower end of the impeller assembly 5; the hole in the middle of the volute front cover 1 is sleeved on the upper part of the motor housing 3, and the volute front cover 1 does not contact the motor housing 3. The outer edge of the volute front cover 1 is fixedly connected to the corresponding protrusions of the volute rear cover 10 through multiple protrusions by bolts;

[0009] The stator coil 13 terminals and Hall sensor leads are axially led to the fan base 9, where they are connected to the integrated intermediate circuit board fixed below the base. The wiring harness is then led out through the circuit board to a standard 8-pin connector, which is then led out to the fan through the volute rear cover 10 and connected to the external control board. The control board cable harness (including the positive and negative power lines, U / V / W three-phase power lines, and Hall signal lines) is introduced here.

[0010] When the stator coil 13 is energized, the magnet sleeve 6 starts to rotate due to electromagnetic induction, and drives the motor housing 3, the motor shaft 7, the impeller assembly 5 and the impeller fixing disc 8 to rotate. The rotation of the impeller assembly 5 forms an eddy current in the volute front cover 1 and the volute rear cover 10, and the eddy current is thrown out from the outlet 2 along with the rotation of the impeller.

[0011] A concave groove having a different shape and the same size as the fan base 9 is designed in the volute rear cover 10, so that the fan base 9 is just embedded in the volute rear cover without relative sliding.

[0012] The impeller assembly 5 is formed in one piece by open moulding.

[0013] The impeller assembly 5 is provided with 13 blades, which are relatively densely packed, thus reducing the fan's sensitivity to wind pressure.

[0014] A three-phase current lead circuit board is welded in the fan base 9, one end of which is connected to the three-phase winding of the stator coil 5, and the other end of the three-phase winding wire is led out through the outlet of the volute rear cover; after the fan is assembled, the outlet should be glued with GD414 to have a waterproof and dustproof effect.

[0015] The impeller assembly 5 and the impeller fixing disc 8 are thermally fused together and then thermally fused together with the motor housing 3 .

[0016] The impeller assembly 5 is fixed to the impeller fixed disc 8 via hot-melt protrusions. There are three hot-melt points between each blade of the impeller assembly 5 and the fixed disc 8 .

[0017] Epoxy resin glue is used to seal the motor housing 3 and the magnet sleeve 6, and the volute rear cover 10 and the volute front cover 1 to prevent explosions caused by weak electric sparks generated during the rotation of the fan, or electric sparks caused by external conductive debris, which may lead to explosions in the mine.

[0018] The gap between the fan base 9 and the edge of the magnet sleeve 6 is between 2 mm and 2.5 mm to prevent friction from causing the entire fan to be assembled unqualified.

[0019] Technical advantages of the present invention

[0020] 1. The present invention designs the impeller assembly 5, stator coil 13, magnet sleeve 6, and motor shaft 7 in the same space. That is, the motor shaft 7 serves as the axis of the impeller assembly 5, stator coil 13, and magnet sleeve 6. Therefore, the present invention greatly reduces the size and weight of the motor, enabling the motor to be used in conjunction with a mine-used powered air supply system, and also making the mine-used powered air supply system very lightweight.

[0021] 2. Existing known data shows that individual powered air supply products are not suitable for use in explosive environments underground in mines and can only be used in non-explosion-proof fields such as welding, medical treatment, and chemistry. This fan was designed as explosion-proof intrinsically safe at the beginning of its design, so it is suitable for use underground in mines;

[0022] 3. According to the underground mine environment, the energy of the fan must be low and no sparks should occur during startup, shutdown or operation. Therefore, according to the national standard, the energy of a micro fan that meets the first-class explosion-proof requirements must be less than 525uJ. The actual energy of the fan under rated working conditions is less than 200uJ. Existing fans rarely meet this energy limit.

[0023] 4. According to the actual use of workers, the entire product needs to be small and lightweight. Therefore, the fan needs to be lightweight while meeting the requirements of high speed and large air volume, and the fan mass should be less than 100g. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 , structural breakdown diagram of the present invention;

[0025] Figure 2 , a schematic diagram of the appearance structure of the impeller assembly of the present invention;

[0026] Figure 3 , a custom mold for the adhesive seal of the present invention;

[0027] Figure 4 , the working control flow chart of the present invention;

[0028] Figure 5 , Actual picture of the stator coil of the present invention;

[0029] Figure 6 , a physical diagram of the present invention;

[0030] Figure 7 , the relationship diagram between the fan, air volume and air pressure of the present invention.

[0031] Among them, 1 is the volute front cover, 2 is the fan outlet, 3 is the motor housing, 4 is the fan shaft sleeve, 5 is the impeller assembly, 6 is the magnet sleeve, 7 is the motor shaft, 8 is the impeller fixing disc, 9 is the fan base, 10 is the volute rear cover, and 13 is the stator coil. DETAILED DESCRIPTION

[0032] The fan of the present invention generally comprises three major components: an impeller, a motor, and a volute. Figure 1 shown.

[0033] The fan includes a volute front cover 1, a volute rear cover 10, a fan outlet 2, a motor housing 3, a fan shaft sleeve 4, an impeller assembly 5, a magnet sleeve 6, a motor shaft 7, an impeller fixing disc 8, and a fan base 9.

[0034] This mini explosion-proof fan is certified explosion-proof. The fan, as the core of the product, meets explosion-proof requirements, achieving low energy, low voltage, low current, and high speed characteristics. The volute front cover 1 is the fan's outer shell. This side of the volute serves as the fan's air inlet. Five raised holes are located on this side of the volute for securing it to the volute rear cover 10 using self-tapping screws. Before securing the volute front cover 1 and the volute rear cover 10, all internal components must be assembled.

[0035] The fan front cover 1 and the fan rear cover 10 should be subjected to fluid simulation according to the fan impeller configuration to obtain the optimal air volume effect.

[0036] The fan shaft sleeve 4 has an interference fit with the motor shaft 7, and its function is to position the internal components, especially the motor shaft 7, and its external motor housing 3 protects and supports the internal electrical components.

[0037] The fan base 9 and motor shaft 7 are designed with an interference fit to prevent relative sliding when the motor rotates. The gap between the fan base 9 and the edge of the magnet sleeve 6 must not exceed 1.5mm to prevent friction that could cause the entire fan assembly to fail. The volute rear cover 10 is designed with a concave configuration that matches the shape and size of the fan base 9, ensuring that the fan base 9 fits snugly within the volute rear cover without relative sliding.

[0038] A circuit board for the fan's three-phase current leads is welded to the fan base 9. One end of the circuit board is connected to the three-phase winding of the stator coil inside the magnet sleeve 6. The other end of the three-phase winding leads out through the outlet on the rear cover of the volute. After the fan is assembled, the outlet is sealed with GD414 glue to ensure waterproof and dustproof effects.

[0039] The fan drives the impeller assembly 5 in a special way. The common driving method is to drive the load to rotate through the motor shaft 7. One of the major innovations of the fan is that the fan shaft and the fan base 9 are interference fit, and the fan base is fixed to the rear cover of the volute. Therefore, the force of the fan shaft 7 acts in reverse on the motor housing 3. After the impeller assembly 5 and the impeller fixing disc 8 are hot-melt together, they are connected to the motor housing 3 as a whole. Therefore, the force of the fan shaft 7 acts in reverse on the motor housing 3, driving the fan impeller to rotate, which is a major innovation in the design of the entire fan.

[0040] To prevent explosions, the entire fan, from the motor housing 3 to the magnet sleeve and then to the fan base 9, is sealed with epoxy resin glue to prevent explosions caused by weak electric sparks generated during the rotation of the fan, or electric sparks caused by external conductive debris, which may lead to explosions in the mine.

[0041] The impeller assembly 5 is formed in one piece by an open mold. The impeller assembly has 13 blades, and the number of blades is relatively close, which reduces the fan's sensitivity to wind pressure.

[0042] The requirement for the number of blades in the fan assembly 14 is mainly to increase the air volume design. When the fan outlet is blocked, the wind pressure changes less, which helps to increase the ventilation volume for miners. The blades are installed to gradually spread out from the center to the edge of the impeller, introducing the air flow from the center and extracting the air volume from the edge of the impeller. The height of the blade is 4mm, and there is no longitudinal deformation. The height of the blade does not change from the center to the edge of the impeller. The angle between the blade axis and the center line of the air inlet is 25°, and the blade angle at the air outlet is 49°. The straight-line distance between adjacent blade outlets is 17mm, and the outer diameter of the air outlet is 70mm.

[0043] The impeller air duct is ensured by the volute front cover 1 and the volute rear cover 10, which is required to reach the air volume required for human breathing at the rated speed. The impeller not only greatly reduces the impeller size and reduces the sensitivity to wind pressure in the case of blockage, but also reduces the impeller's rotational inertia, which is beneficial to the frequent start and stop of the fan and improves the life of the fan.

[0044] The impeller assembly 5 is fixed to the impeller fixed disc 8 by hot melt protrusions. There are three hot melt points between each blade of the impeller assembly 5 and the fixed disc 8, and finally an impeller is formed as a whole. Figure 2 shown.

[0045] The motor adopts a DC brushless outer rotor design, and has the advantages of low operating noise, no spark generation, long life, high efficiency, good speed regulation performance, small size, light weight and good torque characteristics.

[0046] The following are some parameters of motor design:

[0047] Item Unit Parameter Size mm 31 mm * 16 mm Rated voltage V 12 Starting voltage V 7.5V Rated current A 0.26 Rated power consumption W 3.12 Rated speed RPM 4800±10％ Air volume CFM 18.5 Static pressure mmH2O 18.2 Noise dB 51.7

[0048] The motor power supply voltage is 12V low-voltage power supply. According to the maximum air volume requirement of 170L / min, the rated current is about 0.25A, the motor inductance is strictly controlled below 0.6mH, and the motor energy E satisfies E=0.5(1.5×I)×(1.5×I)×L≤525uJ. The energy value after actual design and testing is less than 200uJ, which is far less than the mandatory requirement of coal safety of 525uJ, so as to meet the explosion-proof level Ex ib I Mb and coal safety (MA) certification requirements.

[0049] In addition, the following technical requirements must be met:

[0050] Meet the motor energy requirements: E = 0.5 (1.5 × I) × (1.5 × I) × L ≤ 525uJ;

[0051] Motor selection: DC brushless outer rotor motor;

[0052] Fan control mode: with Hall feedback control mode;

[0053] Fan interface mode: PH2.0-8P terminal block;

[0054] Where E is the motor energy, I is the maximum motor current, and L is the motor inductance. Energy E must be low, based on the principle of high voltage and low inductance, a mandatory requirement for Mine Safety (MA) certification.

[0055] The motor is sealed with glue as a whole, and is processed by custom molds. The motor is sealed with glue and then connected to the impeller. The explosion-proof housing of the motor is sealed with glue using custom molds. Figure 3 For customized molds, epoxy resin glue is used for sealing.

[0056] The control system adopts an electronic control system with Hall feedback control mode, which monitors the operating status of system parameters in real time and adjusts the fan speed and air volume as needed to ensure that the system outputs a constant air volume. The control system also has overcurrent, overvoltage, overheating and other protection functions to ensure the safe and stable operation of the fan. Figure 4 This is the fan control flow chart.

[0057] The fan blades are made of light flame retardant and anti-static ABS material, with small blade radius, low moment of inertia, and reasonable design angle between the blades and the impeller, which ensures the fan has the advantages of large air volume and low noise. In the event of fan blockage, the flow rate will not be affected to a greater extent. Figure 7 This is the relationship diagram of fan air volume and wind pressure.

[0058] 5. Key points of the technical solution of the present invention

[0059] 1) Solve the existing fan technology miniaturization, low energy, high speed, high wind pressure, large air volume and lightweight design;

[0060] 2) It solves the problem of micro fans being used in mines, thereby improving the working and breathing environment of miners;

[0061] 3) It has passed the Class I mining explosion-proof certification, providing new ideas for personal protection.

Claims

1. A mine-used personal protective power air supply explosion-proof micro fan, characterized in that: The invention comprises a volute front cover (1), a motor housing (3), two fan shaft sleeves (4), an impeller assembly (5), a magnet sleeve (6), a motor shaft (7), a stator coil (13), an impeller fixing disc (8), a fan base (9) and a volute rear cover (10) connected together; characterized in that the fan base (9) is fixedly mounted on the volute rear cover (10), the motor housing (3) is installed on the outer wall of the magnet sleeve (6) in an interference fit, the upper end of the motor shaft (7) is fixedly mounted in the center hole of the upper end face of the motor housing (3) by nuts and bolts, the stator coil (13) is between the magnet sleeve (6) and the motor shaft (7), and the upper part of the motor shaft (7) is connected to the center of the stator coil (13) through the fan sleeve (4). On the inner wall of the hole, the lower end of the motor shaft (7) is installed on the central hole of the fan base (9) through the fan shaft sleeve (4); the bottom of the stator coil (13) is fixed on the upper surface of the fan base (9); the motor housing (3) with interference fit with the magnet sleeve (6) is also connected with the impeller assembly (5) through interference fit, and the large hole in the center of the impeller fixing disc (8) is sleeved on the outer wall of the motor housing (3). At the same time, the impeller fixing disc (8) is fixedly connected with the lower end of the impeller assembly (5); the hole in the middle of the volute front cover (1) is sleeved on the upper part of the motor housing (3), and the volute front cover (1) does not contact the motor housing (3). The outer edge of the volute front cover (1) is fixedly connected with the corresponding protrusions of the volute rear cover (10) through multiple protrusions by bolts; The stator coil (13) end and the Hall sensor lead are axially led out to the fan base (9), and then connected to the integrated intermediate circuit board fixed below the base. The wiring harness is led out to an 8-pin standard connector through the circuit board, and then led out to the fan through the volute rear cover (10), and connected to the external control board; the control board cable harness includes the positive and negative power lines, the U / V / W three-phase power lines and the Hall signal line, which are introduced from the external control board; When the stator coil (13) is energized, the magnet sleeve (6) starts to rotate due to electromagnetic induction, and drives the motor housing (3), the motor shaft (7), the impeller assembly (5) and the impeller fixing disc (8) to rotate. The rotation of the impeller assembly (5) forms an eddy current in the volute front cover (1) and the volute rear cover (10), and the eddy current is thrown out from the outlet (2) along with the rotation of the impeller.

2. A mine-used personal protective power air supply explosion-proof micro fan according to claim 1, characterized in that: A concave groove having a different shape and the same size as the fan base (9) is designed in the volute rear cover (10), so that the fan base (9) is just embedded in the volute rear cover without relative sliding.

3. The mine-used personal protective power air supply explosion-proof micro fan according to claim 1 is characterized in that: The impeller assembly (5) is integrally formed by open moulding.

4. The mine-used personal protective power air supply explosion-proof micro fan according to claim 1 is characterized in that: The impeller assembly (5) is provided with (13) blades, the number of which is relatively close, thereby reducing the fan's sensitivity to wind pressure.

5. The mine-used personal protective power air supply explosion-proof micro fan according to claim 1 is characterized in that: A three-phase current lead circuit board is welded in the fan base (9), one end of which is connected to the three-phase winding of the stator coil (5), and the other end of the three-phase winding wire is led out through the outlet of the volute rear cover; the outlet is glued with GD414 after the fan is assembled, which has the effect of waterproofing and dustproofing.

6. The mine-used personal protective power air supply explosion-proof micro fan according to claim 1 is characterized in that: The impeller assembly (5) and the impeller fixing disc (8) are thermally melted into one body, and then thermally melted into one body with the motor housing (3).

7. The mine-used personal protective power air supply explosion-proof micro fan according to claim 1 is characterized in that: The impeller assembly (5) and the impeller fixed disc (8) are fixed via hot-melt protrusions, and there are three hot-melt points between each blade on the impeller assembly (5) and the fixed disc (8).

8. The mine-used personal protective power air supply explosion-proof micro fan according to claim 1 is characterized in that: Epoxy resin glue is used to seal the motor housing (3) and the magnet sleeve (6), and the volute rear cover (10) and the volute front cover (1) to prevent explosion caused by weak electric sparks generated during the rotation of the fan, or electric sparks caused by external conductive debris, which may lead to explosion in the mine.

9. The mine-used personal protective power air supply explosion-proof micro fan according to claim 1 is characterized in that: The gap between the fan base (9) and the edge of the magnet sleeve (6) is between 2 mm and 2.5 mm to prevent friction from causing the entire fan assembly to fail.

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