A limiting device for a movable vane adjustable axial flow fan

Abstract

The present invention relates to a limiting device for a moving blade adjustable axial flow fan. The moving blade adjustable axial flow fan includes blades, the blades are connected to adjusting rods, the adjusting rods are connected to a thrust disc component and a hydraulic cylinder body. A piston is disposed inside a connecting member composed of the thrust disc component and the hydraulic cylinder body. The piston is fixedly connected to and fixed on a spindle flange of the main shaft. A position feedback rod is embedded in the main shaft. The other end of the main shaft is plugged and connected to a control head. The control head is internally provided with an input shaft, a feedback indicating gear and a servo valve. The input shaft and the feedback indicating gear are both meshed and connected to the protruding end of the position feedback rod relative to the main shaft. The servo valve is connected to the position feedback rod. The thrust disc component includes a thrust disc, and a foot for restricting the stroke of the cylinder body is provided on the thrust disc. Compared with the prior art, the present invention has the advantages that the mechanical limiting requirements of fans of different units can be met only by changing the length of the round steel foot, the applicable range is wide, and it is flexible to use, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of fans, and in particular to a limiting device for a movable vane adjustable axial flow fan. Background Art

[0002] The original vane limit of the TLT axial flow movable vane adjustable fan on the market mainly relies on input end signal limit, which can be divided into two types. One is mechanical limit on the control shaft, and the other is signal limit on the servo motor. The main working principles are similar. Both limit the rotation angle of the control shaft, give instructions to control the movement range of the servo spool left and right, so that the cylinder block of the hydraulic cylinder acts within this range, and the blade works within this angle range.

[0003] There are certain safety defects in the original limiting device in the fan. During the operation of the fan, the probability of damage to the fan feedback system is extremely high. Once the feedback system fails, the original limiting device on the fan will also fail, and the oil inlet of the hydraulic cylinder cannot be closed, resulting in continuous oil intake of the hydraulic cylinder until the piston of the hydraulic cylinder travels the full stroke and opens the blade to the maximum position, causing the fan air volume to be too large, and problems such as the mismatch between the maximum power of the fan and the power of the motor and wind grabbing are likely to occur. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned existing technologies and provide a limiting device for a movable vane adjustable axial flow fan.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A limiting device for a movable vane adjustable axial flow fan, the movable vane adjustable axial flow fan includes a blade, the blade is connected to an adjusting rod, the adjusting rod is connected to a thrust disc component and a cylinder block of a hydraulic cylinder, a piston is arranged inside a connecting member composed of the thrust disc component and the cylinder block of the hydraulic cylinder, the piston is fixedly connected to a main shaft and fixed on a main shaft flange, a position feedback rod is embedded in the main shaft, the other end of the main shaft is plugged and connected to a control head, the control head is internally provided with an input shaft, a feedback indicating gear and a servo valve, the input shaft and the feedback indicating gear are both meshed and connected to the extending end of the position feedback rod relative to the main shaft, the servo valve is connected to the position feedback rod, the thrust disc component includes a thrust disc, and the thrust disc is provided with a pad for limiting the stroke of the cylinder block.

[0007] Further, the structure of the pad is a cylindrical structure.

[0008] Further, the number of the pads is at least 4.

[0009] Further, the pad is made of steel.

[0010] Furthermore, the foot pads are arranged on the thrust disk in a circumferential distribution.

[0011] Furthermore, the thrust disk includes a foot pad mounting portion and a boss portion, and a mounting hole is provided at the center position of the boss portion.

[0012] Furthermore, the servo valve is connected to the position feedback rod through a connecting rod.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. Safe and reliable: During the operation of the fan, the probability of damage to the fan feedback system is extremely high. Once the feedback system fails, the original limit device on the fan will also fail, and the oil inlet of the hydraulic cylinder cannot be closed, resulting in continuous oil injection into the hydraulic cylinder until the piston of the hydraulic cylinder travels the full stroke and opens the blade to the maximum position, causing the fan air volume to be too large, and problems such as the mismatch between the maximum power of the fan and the power of the motor and wind grabbing are likely to occur. However, the present invention uses the stroke of the hydraulic cylinder block to limit the blade angle. Even in the extreme case where the fan feedback is invalid, it can still limit the maximum opening of the moving blade and prevent the blade angle from being too large, making it safer and more reliable.

[0015] 2. Low transformation cost: The transformation of the limit device is convenient. The foot pads of the thrust disk are directly used to limit the stroke of the hydraulic cylinder block, and there is no need to replace the type of the hydraulic cylinder, reducing the transformation cost and having high economic energy-saving performance.

[0016] 3. Wide application range: Since this limit device uses round steel foot pads to limit the cylinder stroke, only by changing the length of the round steel foot pads can the mechanical limit requirements of different unit fans be met, with a wide applicable range and flexible operation.

[0017] 4. Easy maintenance: During periodic maintenance, the round steel can be replaced as a whole. Brief Description of the Drawings

[0018] Figure 1 It is the internal structure diagram of the blade adjustment system of the TLT axial flow adjustable moving blade fan using the limit device of the present invention;

[0019] Figure 2 It is the side view of the limit device of the present invention;

[0020] Figure 3 It is the front view of the limit device of the present invention;

[0021] In the figure, 1 is the blade, 2 is the adjusting rod, 3 is the piston, 4 is the hydraulic cylinder block, 5 is the main shaft, 6 is the control head, 7 is the position feedback rod, 8 is the input shaft, 9 is the servo valve, 10 is the feedback indicating gear, 11 is the thrust disk assembly, 12 is the thrust disk, 121 is the foot pad mounting portion, 122 is the boss portion, 13 is the foot pad, and 14 is the main shaft flange. Detailed implementation manners

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] Embodiment

[0024] 1. Device structure:

[0025] As shown in Figure 2 and Figure 3 a mechanical limit device for the blades of a variable-blade adjustable axial-flow fan, this device is mainly improved on the original thrust disk. In the present invention, 4 round steel feet 13 are added to the thrust disk 12 to limit the stroke of the cylinder body of the hydraulic cylinder. The length of the feet is the length required to limit the stroke of the cylinder body, and it can be modified according to the mechanical limit requirements of different unit fans.

[0026] 2. Improvements:

[0027] As shown in Figure 1 taking the process of the variable blade of the fan opening as an example, assuming that 80% of the mechanical limit is set on the control shaft, when the control shaft rotates clockwise to the maximum of 80%, the movement stops, and the spool of the servo valve moves to the 80% position accordingly. The pressure oil port is connected to oil passage A, and the oil return port is connected to oil passage B. Through the pressure difference of the hydraulic oil before and after, the cylinder body of the hydraulic cylinder moves continuously to the left, and the opening of the variable blade increases. When the feedback system works normally, when the hydraulic cylinder moves to the left, the feedback rod (adjusting rod) also moves to the left together, and the valve sleeve of the servo valve moves to the left together with the feedback rod through the connecting rod, and once again blocks the oil holes of oil passage B and A, and the variable blade of the fan stops opening at 80% and no longer increases. When the feedback system fails and the valve sleeve of the servo valve does not move with the feedback rod, and the oil holes of oil passage B and A continue to intake and return oil, it will cause the hydraulic cylinder to continue to move to the left, and the variable blade continues to open beyond 80% until the hydraulic cylinder moves to the maximum stroke and is no longer controlled by the 80% mechanical limit on the control shaft, that is, the limit of the variable blade opening set on the control shaft is invalid when the feedback system fails.

[0028] However, the mechanical limit device involved in the present invention can still limit the maximum opening of the variable blade even in the extreme case where the fan feedback is invalid, and prevent the blade angle from being too large.

[0029] The round steel feet 13 are installed on the thrust disk 12, and the round steel feet 13 can be replaced according to the required limit requirements.

[0030] 3. Working principle:

[0031] The existing TLT axial-flow adjustable-blade fan on the market, such as Figure 1 shown, has a generally similar adjustable-blade opening principle. When hydraulic oil enters the inside of the hydraulic cylinder through the oil inlet of the servo valve 9, since the front and rear positions of the piston 3 are fixed, the cylinder block 4 of the hydraulic cylinder will move back and forth due to the pressure difference of the hydraulic oil. The connecting thrust disk 12 pushes the blade adjusting rod 2 to adjust the opening of the blade 1. Therefore, the movement of the cylinder block 4 of the hydraulic cylinder changes the movement angle of the blade, and the maximum movement angle of the blade is related to the stroke of the hydraulic cylinder. The greater the stroke of the hydraulic cylinder, the greater the maximum movement angle of the blade.

[0032] Since the thrust disk 12 is rigidly connected to the cylinder block 4 of the hydraulic cylinder, the present invention adds 4 round steel feet 13 to the thrust disk 12 to limit the stroke of the cylinder block 4 of the hydraulic cylinder. The length of the feet 13 is the length required to limit the stroke of the cylinder block, and it can be modified according to the mechanical limit requirements of the fans of different units.

[0033] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art in the technical field disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A limiting device for a movable vane adjustable axial flow fan, the movable vane adjustable axial flow fan comprising a blade (1), the blade (1) being connected to an adjusting rod (2), the adjusting rod (2) being connected to a thrust disc member (11) and a hydraulic cylinder body (4), a piston (3) being disposed inside a connecting member composed of the thrust disc member (11) and the hydraulic cylinder body (4), the piston (3) being fixedly connected to a main shaft (5) and fixed to a main shaft flange (14), a position feedback rod (7) being embedded in the main shaft (5), the other end of the main shaft (5) being plugged and connected to a control head (6), the control head (6) being internally provided with an input shaft (8), a feedback indicating gear (10) and a servo valve (9), both the input shaft (8) and the feedback indicating gear (10) being meshed and connected to an extended end of the position feedback rod (7) relative to the main shaft (5), the servo valve (9) being connected to the position feedback rod (7), characterized in that, The thrust disc component (11) includes a thrust disc (12), and a foot (13) for restricting the cylinder stroke is provided on the thrust disc (12); The structure of the foot (13) is a cylindrical structure; The feet (13) are arranged on the thrust disc (12) in a circumferential distribution; The thrust disc (12) includes a foot mounting portion (121) and a boss portion (122), and a mounting hole is provided at the central position of the boss portion (122).

2. The limit device for a movable blade adjustable axial flow fan according to claim 1, characterized in that, The number of the feet (13) is at least 4; 3. The limiting device for a movable blade adjustable axial flow fan according to claim 1, characterized in that, The feet (13) are made of steel; 4. The limit device for a movable vane adjustable axial flow fan according to claim 1, characterized in that, The servo valve (9) is connected to the position feedback rod (7) through a connecting rod.

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