A non-leakage centrifugal fan with a combination seal

Abstract

The utility model discloses a kind of non-leakage centrifugal fan of combined sealing, it includes impeller and shell;The leaf and rear side of wheel disc design auxiliary blade;The auxiliary blade and shell rear side plate axial gap A;The impeller and transmission group main shaft adopt key connection;The outer end surface of impeller adopts pressure cap and transmission group main shaft fixed;Shell rear side plate hole and main shaft cooperation place, design carbon ring seal.The impeller of the utility model and main shaft adopt small interference fit, impeller outer end adopts protective cap and is pressed tightly, guarantee that impeller long-term operation does not damage end cover and falls off.

Description

Technical Field

[0001] This utility model pertains to a ventilation device, specifically a leak-proof centrifugal fan. Background Technology

[0002] Centrifugal fans offer advantages such as high flow rate and high pressure, making them widely used in various applications including pneumatic conveying of starch, chemicals, cement, and powdered gases. However, for fans conveying high-pressure, high-temperature gases, packing seals or mechanical seals are typically used. These seals are insufficient to meet the pollution-free requirements for food processing, and their complex structure and high manufacturing costs further complicate their application.

[0003] Currently, there is no feasible single sealing technology to solve the problem of preventing leakage in the transportation of powdered gases; nor is there a reliable solution to ensure that the casing displacement caused by high-temperature media does not affect the sealing effect. Utility Model Content

[0004] The purpose of this utility model is to provide a leak-proof centrifugal fan. The impeller is a welded structure of high-efficiency blade profiles and a steel plate on the impeller cover and disc. By adopting reasonable blade profiles and flow channel dimensions, the impeller can ensure high-efficiency work in terms of flow rate and pressure. High-efficiency secondary blades are designed on the rear side of the impeller disc in the opposite direction to the blades. The air volume generated by the secondary blades is slightly greater than the leakage of the rear shaft clearance, and the pressure of the secondary blades is slightly higher than the overflow pressure of the leaked gas at the shaft extension. In view of the temperature and corrosion characteristics of the conveyed medium, a floating carbon ring seal is designed on the outer side of the casing side plate to resist the corrosion of the conveyed medium and to overcome the expansion displacement of the casing caused by temperature changes.

[0005] This utility model is achieved using the following technical solution: a combined sealed leak-proof centrifugal fan, which optimizes the impeller profile design by using a plate-shaped bending or slight twisting form to meet the precision forming process of steel plate blanking; it includes an impeller and a casing; the impeller and the rear side of the impeller disc are designed with auxiliary blades; the auxiliary blades and the rear side plate of the casing have an axial clearance A; the impeller and the main shaft of the transmission assembly are connected by a key; the outer end face of the impeller is fixed to the main shaft of the transmission assembly by a pressure cap; the hole of the rear side plate of the casing mates with the main shaft of the transmission assembly and is designed with a carbon ring seal.

[0006] A further improvement of this invention is that a high-efficiency auxiliary blade is designed on the rear side of the wheel, with a number that is prime to the number of the blades.

[0007] A further improvement of this utility model is that 2-3 carbon ring auxiliary seals are designed on the outer side of the rear side plate of the housing.

[0008] A further improvement of this invention is that the auxiliary sealing carbon ring is tightly fitted to the main shaft and does not rotate with the main shaft.

[0009] A further improvement of this invention is that the auxiliary carbon ring sealing jacket is designed with a carbon ring groove that allows the carbon ring to move and provides good sealing performance.

[0010] Compared with the prior art, the advantages of this utility model are: This invention offers better powder media conveying performance compared to conventional structure fans, and the auxiliary blades do not generate pollution but can be used for a long time. This invention has better adaptability than conventional fans, and completely avoids the failure of seal damage caused by the linear expansion displacement of the casing due to changes in the temperature of the conveyed gas. The shape and structure of the auxiliary blade inlet of this utility model ensures the high efficiency and stability of the long-term operation of the leak-proof fan. The impeller disc and hub of this utility model are connected by riveting with large rivet heads or by high-strength bolts with protective caps, which ensures the overall high strength and wear resistance of the impeller. The impeller and main shaft of this invention adopt a small interference fit, and the outer end of the impeller is pressed with a protective cap to ensure that the end cap will not be damaged and fall off during long-term operation of the impeller. Attached Figure Description

[0011] Figure 1 This is a product structure diagram of this utility model; Figure 2 This is a diagram of the impeller, a component of this utility model product; Figure 3 This is a utility model Figure 2 The left-hand view; Figure 4 This is a rear sealing diagram of this utility model; Figure 5 This is the utility model Figure 4 The left-hand view; Detailed Implementation

[0012] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0013] In the diagram: 1. Casing; 2. Impeller; 3. Pressure cap; 4. Transmission assembly main shaft; 5. Carbon ring seal; 6. Blade; 7. Secondary blade; 8. Rivet protection; 9. Wheel disc; 10. Hub; 11. Sealing body; 12. Locating pin; 13. Cylindrical head screw; 14. Countersunk hole; 15. Fixing plate; 16. Sealing gasket; 17. Fixing bolt; 18. Carbon ring groove; 19. Carbon ring; 20. Adjusting positioning block; 21. Adjusting screw; 22. Fixing screw; 23. Nitrogen port.

[0014] A leak-proof centrifugal fan with a combined seal includes an impeller 2 and a casing 1; the impeller 2 and the impeller disk 9 are designed with auxiliary blades 7 on their rear sides; the auxiliary blades 7 have an axial clearance A with the rear side plate of the casing; the impeller 2 is connected to the main shaft 4 of the transmission assembly by a key; the outer end face of the impeller 2 is fixed to the main shaft 4 of the transmission assembly by a pressure cap 3; the rear side plate hole of the casing 1 mates with the main shaft 4 of the transmission assembly, and is designed with a carbon ring seal 5.

[0015] See attached document Figure 1 , Figure 2 The blade 6 is laser-marked and tenon-positioned welded to the wheel disk 9; the wheel disk 9 is connected to the hub 10 with large round head protective rivets; the outer side of the wheel disk 9 is designed with auxiliary blades 7, the width B of which is determined by the air volume required for sealing and the gap A between the blades and the rear side plate of the casing, and is generally controlled to be 3 to 5 mm.

[0016] See attached document Figure 2 , Figure 3 The number of the secondary blades 7 and the blades 6 are coprime; the inlet installation angle β3 of the secondary blade 7 is greater than the inlet installation angle β1 of the blade 6; the outlet installation angle β4 of the secondary blade 7 is slightly greater than the outlet installation angle β2 of the blade 6.

[0017] See attached document Figure 1 , Figure 4 , Figure 5 The sealing body 11 of the carbon ring seal 5 is designed with an external split structure, with a threaded hole at one end and a countersunk hole at the other end. A cylindrical positioning pin 12 is designed on the split surface. The two ends of the sealing body 11 are pressed together with cylindrical head screws 13. The fixing plate 15 is welded to the outer side of the rear plate of the housing 1. A sealing gasket 16 is designed between the sealing body 11 and the fixing plate, and they are connected and fixed with fixing bolts 17.

[0018] See attached document Figure 4 , Figure 5 The sealing body 11 is designed with a carbon ring groove 18; the width of the carbon ring groove 18 is increased by 0.3 to 0.5 mm compared with the carbon ring 19; the depth of the carbon ring groove 18 is 5 to 8 mm greater than that of the carbon ring 19 on one side.

[0019] Reference Figure 1 , Figure 5 The carbon ring 19 is designed with an insertable split spring for securing it, and the inner side of the carbon ring 19 has a gapless contact with the transmission assembly main shaft 4. When assembling the carbon ring seal 5 with the transmission assembly main shaft 4, the adjusting screw 21 of the split adjusting positioning block 20 is used for circumferential adjustment to ensure that the axial clearance between the ring seal 5 and the main shaft 4 is uniform. The adjusting positioning block 20 remains stationary during the installation and transportation of the fan. Before starting the fan, the adjusting screw 21 is loosened, the fixing screw 22 is removed, and the adjusting positioning block 20 is taken out.

[0020] Reference Figure 4The sealing body 11 is designed with a nitrogen pore 23. For fans with strict sealing requirements and zero leakage, connecting nitrogen gas with a pressure higher than the leakage gas pressure or a tool gas that does not react with the conveying medium will have a better effect in forcibly blocking gas leakage. Compared with the prior art, the beneficial effects of this utility model are: This invention offers better powder media conveying performance compared to conventional structure fans, and the auxiliary blades do not generate pollution but can be used for a long time. This invention has better adaptability than conventional fans, and completely avoids the failure of seal damage caused by the linear expansion displacement of the casing due to changes in the temperature of the conveyed gas. The shape and structure of the auxiliary blade inlet of this utility model ensures the high efficiency and stability of the long-term operation of the leak-proof fan. The impeller disc and hub of this utility model are connected by riveting with large rivet heads or by high-strength bolts with protective caps, which ensures the overall high strength and wear resistance of the impeller. The impeller and main shaft of this invention adopt a small interference fit, and the outer end of the impeller is pressed with a protective cap to ensure that the end cap will not be damaged and fall off during long-term operation of the impeller.

[0021] This utility model discloses a leak-proof centrifugal fan with combined sealing. It uses the dynamic directional air pressure of the auxiliary blades to prevent powdery gases from overflowing from the shaft seal on the rear side plate of the casing, thus preventing pollution of the conveyed medium. It adopts a floating carbon ring seal, which effectively prevents the leakage of special gases such as corrosive and high-temperature gases. It can solve the problem of overflow of powdery or corrosive media polluting the environment, and can solve the problem of seal failure or damage caused by the different expansion of the casing and the main shaft when conveying high-temperature gases. It is suitable for use in various fans with strict leak-proof requirements.

[0022] Although the present invention has been described above, various modifications can be made to it and equivalent components can be replaced without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features disclosed in the present invention can be combined with each other in any way. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to what is disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A leak-proof centrifugal fan with combined sealing, comprising an impeller (2) and a casing (1); the impeller (2) and the impeller disc (9) are designed with auxiliary blades (7) on their rear sides; the auxiliary blades (7) have an axial clearance A with the rear side plate of the casing; the impeller (2) is connected to the main shaft (4) of the transmission group by a key; the outer end face of the impeller (2) is fixed to the main shaft (4) of the transmission group by a pressure cap (3); the rear side plate hole of the casing (1) is designed with a carbon ring seal (5) to fit with the main shaft (4).

2. The leak-proof centrifugal fan with combined sealing according to claim 1, characterized in that: The blade (6) is laser-marked and tenon-positioned welded to the wheel (9); the wheel (9) is connected to the hub (10) with large round head protective rivets; the outer side of the wheel (9) is designed with a secondary blade (7), the width B of which is determined based on the required air volume for sealing and the gap A between the blade and the rear side plate of the casing, and is generally controlled to be 3 to 5 mm.

3. A leak-proof centrifugal fan with combined sealing according to claim 2, characterized in that: The number of the secondary blades (7) and the blades (6) are coprime; the inlet installation angle β3 of the secondary blades (7) is greater than the inlet installation angle β1 of the blades (6); the outlet installation angle β4 of the secondary blades (7) is slightly greater than the outlet installation angle β2 of the blades (6).

4. A leak-proof centrifugal fan with combined sealing according to claim 1, characterized in that: The sealing body (11) of the carbon ring seal (5) is designed with an external split structure, with a threaded hole at one end and a countersunk hole at the other end. A cylindrical positioning pin (12) is designed on the split surface. The two ends of the sealing body (11) are pressed together with cylindrical head screws (13). The fixing plate (15) is welded to the outer side of the rear side plate of the housing (1). A sealing gasket (16) is designed between the sealing body (11) and the fixing plate, and they are connected and fixed with fixing bolts (17).

5. A leak-proof centrifugal fan with combined sealing according to claim 4, characterized in that: The sealing body (11) is designed with a carbon ring groove (18); the width of the carbon ring groove (18) is 0.3 to 0.5 mm greater than that of the carbon ring (19); the depth of the carbon ring groove (18) is 5 to 8 mm greater than that of the carbon ring (19) on one side.

6. A leak-proof centrifugal fan with a combined seal according to claim 5, characterized in that: The carbon ring (19) is designed with an insertable split spring for binding, and the inner side of the carbon ring (19) is in contact with the transmission group main shaft (4) without clearance. When the carbon ring seal (5) is assembled with the transmission group main shaft (4), the adjusting screw (21) of the split adjusting positioning block (20) is used for circumferential adjustment to make the axial clearance between the ring seal (5) and the main shaft (4) uniform. The adjusting positioning block (20) remains in place during the installation and transportation of the fan. Before the fan is started, the adjusting screw (21) is loosened, the fixing screw (22) is removed, and the adjusting positioning block (20) is taken out.

7. A leak-proof centrifugal fan with combined sealing according to claim 4, characterized in that: The sealing body (11) is designed with a nitrogen vent (23). For fans with strict sealing requirements and zero leakage, nitrogen or tool gas that does not react with the conveying medium is connected to the gas with a pressure higher than the leakage gas pressure to forcibly block the external leakage of gas.

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