Optical detection system for furfural in transformer oil

Abstract

The invention discloses an optical detection system for furfural in transformer oil, and relates to the technical field of oil body detection. The spiral plate and the flow dividing cover are arranged on the inner wall of the oil inlet pipe, and impurity particles in oil of the compressor are effectively separated through centrifugal force in rotating oil flow. The density of the impurity particles is far greater than that of the oil body, so that the impurity particles rotate on the inner wall of the oil inlet pipe and move along the edge of the pipe wall without entering the axis of the pipeline; by arranging the turbulent flow shielding cover in the detection chamber and utilizing the guiding effect of the pressure difference of the oil body, the device can realize the static state of the oil body in the detection chamber. The static oil body reduces the influence of molecular flow of the oil body on measurement, and the measurement precision of the spectrum detector is effectively improved. The design of the shielding cover ensures the oil body isolation of the detection chamber and the stability of the measurement environment, so that the detection precision is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil detection, in particular to an optical detection system for furfural in transformer oil. Background Art

[0002] Most of the existing compressor oil detection devices are easy to fix on the compressor oil pipeline through a simple installation method, and usually have a sampling device at the front end to allow the compressor oil to flow evenly, thereby improving the detection effect of the oil body. In these devices, the sampling device is often equipped with a filter to remove larger particle impurities in the compressor oil to avoid damage to the internal optical detection components. Such devices usually rely on a light source to emit a beam of light, penetrate the compressor oil, and then use spectral analysis software to process the acquired spectral data to analyze the components in the compressor oil. This method can accurately identify key components in the compressor oil, such as furfural, by optical means.

[0003] However, the existing technology has the following significant disadvantages in practical applications. First, although the use of the filter can block larger impurities, it will gradually become clogged as impurities accumulate, resulting in poor oil flow, which affects the accuracy of detection and the operating efficiency of the equipment. The filter needs to be frequently replaced and cleaned, increasing maintenance costs. Second, the impurities in the compressor oil may not be completely evenly distributed when flowing through the sampling device, which may easily cause the oil sample penetrated by the light source to fail to truly reflect the overall composition of the compressor oil, affecting the accuracy of the test results. Summary of the invention

[0004] In order to overcome the defects of the above-mentioned prior art, the present invention provides the following technical solutions: an optical detection system for furfural in transformer oil, comprising an oil inlet pipe, a plurality of spiral plates are fixed on the inner wall of the oil inlet pipe, a diverter hood coaxially arranged with the oil inlet pipe is fixed at one end of the spiral plates, and an oil inlet gap is arranged between the inner wall of the oil inlet pipe and the diverter hood; flanges and connecting pipe rings are fixed at both ends of the oil inlet pipe, wherein a separation pipe is fixed on the connecting pipe ring, a detection pipe is fixed to the inner wall of the separation pipe through a plurality of reinforcing plates, an auxiliary fan is rotatably provided at one end of the detection pipe close to the oil inlet pipe, and a motor is fixed to the axial position of the detection pipe through a plurality of motor support plates; wherein four detection support rods and a control support beam are fixed between two adjacent motor support plates, wherein the four detection support rods are fixed with detection parts for detecting furfural in transformer oil.

[0005] Preferably, a turbine bracket is fixed on the output shaft of the motor, a driving turbine is fixed on the turbine bracket, the driving turbine rotates in cooperation with the end of the detection tube away from the spiral plate, and an auxiliary fan is also fixed on the output shaft of the motor; wherein an oil discharge pipe and a flange are respectively fixed on the separation pipe and the oil inlet pipe.

[0006] Preferably, the detection part includes a detection chamber fixedly matched with the detection support rod, and two ends of the detection chamber are in contact and sliding cooperation with two symmetrically arranged spoiler shielding covers, and the two spoiler shielding covers are used to block the two ends of the detection chamber; the two spoiler shielding covers are fixed on the shielding cover bracket, and the shielding cover bracket is slidably arranged on two of the detection support rods, and a reset spring is arranged around the two detection support rods, and the two ends of the reset spring are fixed to the shielding cover bracket and the inner wall of the detection tube.

[0007] Preferably, a limiting ring is fixed on the shielding cover bracket, a force plate is rotatably provided on the limiting ring, a rotation limiting column is rotatably provided on the inner wall of the limiting ring, and the rotation limiting column and the limiting ring are fixed and synchronously transmitted via a rotating shaft; a snap-in groove is provided on the rotation limiting column in a symmetrical layout, and the snap-in groove includes two symmetrically arranged inclined surfaces and a straight surface, wherein the inclined surfaces and the straight surface are perpendicular to each other.

[0008] Preferably, there are locking columns frictionally sliding between the inclined surface and the inner wall of the limiting ring, and an elastic sheet is elastically connected between the locking column and the straight surface; a lever is provided in contact with the two locking columns inside each clamping groove, and the two levers are fixed on the active turntable, the active turntable and the limiting ring rotate in cooperation, and the active turntable and the limiting ring cannot move axially.

[0009] Preferably, a dial is coaxially fixed on the active turntable, and a plurality of passive dial plates are arranged in a circular array on the circumferential surface of the dial; a plurality of first limiting dial plates and a plurality of second limiting dial plates are respectively arranged in a linear array at the middle position and one end position on the control support beam, and all the first limiting dial plates and the second limiting dial plates are in contact with and cooperate with the passive dial plates to drive the dial to rotate.

[0010] Preferably, there are at least six first limiting plates and at least six second limiting plates, and all of the first limiting plates and the second limiting plates are rotationally matched with the control support beam, and torsion springs are provided at the rotational connections between the first limiting plates and the second limiting plates and the control support beam, and all of the first limiting plates and the second limiting plates are provided with protrusions at one end away from the passive plate.

[0011] Preferably, a first limiting block is fixedly provided at the position of each first limiting plate protrusion on the control support beam, and the first limiting block contacts and cooperates with the protrusion on the first limiting plate; a second limiting block is fixed at the position of the second limiting plate protrusion on the control support beam, and the second limiting block contacts and cooperates with the protrusion on the second limiting plate; the second limiting block is located on the side of the second limiting plate protrusion close to the spoiler shield, and the first limiting block is located on the side of the first limiting plate protrusion away from the spoiler shield.

[0012] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses the spiral plate and the flow divider structure arranged on the inner wall of the oil inlet pipe to effectively separate the impurity particles in the compressor oil by using the centrifugal force in the rotating oil flow. The density of the impurity particles is much greater than the density of the oil body, so the impurity particles rotate on the inner wall of the oil inlet pipe and move along the edge of the pipe wall without entering the axis of the pipe; (2) The present invention sets a spoiler shield in the detection chamber and uses the guiding effect of the oil pressure difference, so that the device can achieve the static state of the oil body in the detection chamber. The static oil body reduces the influence of the oil body molecular flow on the measurement, and effectively improves the measurement accuracy of the spectral detector. The design of the shield ensures the isolation of the oil body in the detection chamber and the stability of the measurement environment, thereby improving the detection accuracy; (3) The tunable laser light source arranged in the detection chamber of the present invention can accurately analyze the static oil body. With the high-sensitivity spectral detector, the device can accurately identify furfural in the compressor oil and realize efficient and accurate environmental monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the external structure of the present invention.

[0014] Figure 2 It is a schematic diagram of the overall structure of the present invention.

[0015] Figure 3 It is a structural schematic diagram of the auxiliary fan of the present invention.

[0016] Figure 4 It is a schematic diagram of the structure of the detection chamber of the present invention.

[0017] Figure 5 For the present invention Figure 4 Schematic diagram of the structure at point A in the middle.

[0018] Figure 6 For the present invention Figure 4 Schematic diagram of the structure at point B in the middle.

[0019] Figure 7 It is a schematic diagram of the structure of the limiting cylinder ring of the present invention.

[0020] Figure 8 This is a schematic diagram of the structure of the rotation limiting column of the present invention.

[0021] Fig. 9 For the present invention Figure 8 Schematic diagram of the structure at point C in the middle.

[0022] In the figure: 101-inlet pipe; 102-dividing cover; 103-spiral plate; 104-connecting pipe ring; 105-detection pipe; 106-auxiliary fan; 107-separation pipe; 108-reinforcement plate; 109-motor; 110-motor support plate; 111-driving turbine; 112-turbine bracket; 113-detection support rod; 114-control support beam; 115-reset spring; 116-detection chamber; 117-spoiler shield; 118 - shielding cover bracket; 119- limiting ring; 120- force plate; 121- rotation limiting column; 122- active turntable; 123- dial; 124- lever; 125- stuck column; 126- elastic sheet; 127- inclined plane; 128- straight plane; 129- oil discharge pipe; 130- flange; 131- first limiting plate; 132- first limiting block; 133- passive plate; 134- second limiting plate; 135- second limiting block. DETAILED DESCRIPTION

[0023] The following is combined with Figure 1-9 , and further illustrate the technical solution of the present invention through specific implementation methods.

[0024] The present invention provides an optical detection system for furfural in transformer oil, comprising an oil inlet pipe 101, a plurality of spiral plates 103 are fixed on the inner wall of the oil inlet pipe 101, a flow divider 102 coaxially arranged with the oil inlet pipe 101 is fixed at one end of the spiral plates 103, an oil inlet gap is arranged between the inner wall of the oil inlet pipe 101 and the flow divider 102; flanges 130 and connecting pipe rings 104 are fixed at both ends of the oil inlet pipe 101, wherein a separation pipe 107 is fixed on the connecting pipe ring 104, and the separation pipe 107 The inner wall is fixed with a detection tube 105 through a plurality of reinforcing plates 108, and an auxiliary fan 106 is rotatably provided at one end of the detection tube 105 close to the oil inlet pipe 101. A motor 109 is fixed at the axial position of the detection tube 105 through a plurality of motor support plates 110; wherein four detection support rods 113 and a control support beam 114 are fixed between two adjacent motor support plates 110, wherein a detection part is fixed on the four detection support rods 113, and is used to detect furfural in the compressor oil. A turbine bracket 112 is fixed on the output shaft of the motor 109, and a driving turbine 111 is fixed on the turbine bracket 112, and the driving turbine 111 is rotatably matched with the end of the detection tube 105 away from the spiral plate 103, and an auxiliary fan 106 is also fixed on the output shaft of the motor 109; wherein an oil body discharge pipe 129 and a flange 130 are respectively fixed on the separation tube 107 and the oil inlet pipe 101.

[0025] The detection part includes a detection chamber 116 fixedly matched with the detection support rod 113, and two ends of the detection chamber 116 are in contact and sliding cooperation with two symmetrically arranged spoiler shielding covers 117, and the two spoiler shielding covers 117 are used to block the two ends of the detection chamber 116; the two spoiler shielding covers 117 are fixed on the shielding cover bracket 118, and the shielding cover bracket 118 is slidably arranged on two of the detection support rods 113, and a return spring 115 is arranged around the two detection support rods 113, and the two ends of the return spring 115 are fixed to the shielding cover bracket 118 and the inner wall of the detection tube 105. A limiting ring 119 is fixed on the shielding cover bracket 118, and a force plate 120 is rotatably provided on the limiting ring 119. A rotation limiting column 121 is rotatably provided on the inner wall of the limiting ring 119, and the rotation limiting column 121 and the limiting ring 119 are fixed and synchronously transmitted via a rotating shaft; a snap-in groove is provided on the rotation limiting column 121 in a symmetrical layout, and the snap-in groove includes two symmetrically arranged inclined surfaces 127 and a straight surface 128, wherein the inclined surfaces 127 and the straight surface 128 are perpendicular to each other. There are locking columns 125 frictionally sliding between the inclined surface 127 and the inner wall of the limiting cylinder ring 119, and an elastic sheet 126 is elastically connected between the locking column 125 and the straight surface 128; a lever 124 is contacted between the two locking columns 125 inside each clamping groove, and the two levers 124 are fixed on the active rotating disk 122, and the active rotating disk 122 and the limiting cylinder ring 119 are rotationally matched, and the active rotating disk 122 and the limiting cylinder ring 119 cannot move axially. A dial 123 is coaxially fixed on the active rotating disk 122, and a plurality of passive dial plates 133 are arranged in a circular array on the circumferential surface of the dial 123; a plurality of first limiting dial plates 131 and a plurality of second limiting dial plates 134 are arranged along a linear array at the middle position and one end of the control support beam 114, and all the first limiting dial plates 131 and the second limiting dial plates 134 are in contact with the passive dial plates 133 to drive the dial 123 to rotate. There are at least six first limiting plates 131 and at least six second limiting plates 134, and all of the first limiting plates 131 and the second limiting plates 134 are rotationally matched with the control support beam 114, and a torsion spring is provided at the rotational connection between the first limiting plates 131 and the second limiting plates 134 and the control support beam 114, and a protrusion is provided on the end of all of the first limiting plates 131 and the second limiting plates 134 away from the passive plate 133.A first limiting block 132 is fixedly provided at the position of each protrusion of the first limiting dial plate 131 on the control support beam 114, and the first limiting block 132 is in contact with and cooperates with the protrusion on the first limiting dial plate 131; a second limiting block 135 is fixed at the position of the protrusion of the second limiting dial plate 134 on the control support beam 114, and the second limiting block 135 is in contact with and cooperates with the protrusion on the second limiting dial plate 134; the second limiting block 135 is located on the side of the protrusion of the second limiting dial plate 134 close to the spoiler shield 117, and the first limiting block 132 is located on the side of the protrusion of the first limiting dial plate 131 away from the spoiler shield 117.

[0026] The whole is installed inside the compressor oil through the flange 130, so the compressor oil will enter the spiral plate 103 through the gap between the diverter cover 102 and the oil inlet pipe 101, and then the impurity particles and oil in the compressor oil will rotate under the guidance of the spiral plate 103 (because the diverter cover 102 is set, the oil will flow toward the spiral plate 103, so the spiral plate 103 will drive the oil to rotate). The rotating oil and impurity particles will be subjected to centrifugal force, because the density of the impurity particles is much greater than the density of the oil, so the impurity particles will rotate and move on the inner wall of the oil inlet pipe 101. Therefore, these impurity particles will not move to the axial position of the oil inlet pipe 101, and the impurity particles and oil moving along the inner wall edge of the oil inlet pipe 101 will be discharged through the gap between the separation tube 107 and the detection tube 105. During the discharge process, the driving turbine 111 will be driven to rotate, and the rotation of the driving turbine 111 will drive the output shaft of the motor 109 to rotate, and the output shaft of the motor 109 will drive the auxiliary fan 106 to rotate. At this time, the auxiliary fan 106 will suck the oil at the axial position of the oil inlet pipe 101 into the detection tube 105 (this step mainly plays an auxiliary role, because the oil will automatically enter the detection tube 105 under the action of the pressure difference).

[0027] Since the detection chamber 116 is arranged in the detection tube 105, the oil body can enter the detection chamber 116. When the two spoiler shields 117 are in a deviated position from the detection chamber 116, the oil body will enter the detection chamber 116, and then the two spoiler shields 117 will move to a position coaxial with the detection chamber 116, and the two spoiler shields 117 will trap this part of the oil body in the detection chamber 116, and the spoiler shields 117 can drain the surrounding oil body to the outside of the detection chamber 116. A tunable laser light source is arranged inside the detection chamber 116, and the light source will irradiate the stationary oil body in the detection chamber 116 (making the oil body stationary can reduce the influence of the oil body molecule flow on the measurement, because the oil body density distribution is uneven and it is still in a rotating state). When the laser interacts with the molecules of the substance, the frequency of part of the scattered light changes, and this frequency change reflects the vibration and rotation inside the molecule, thereby analyzing the composition of the oil body. A high-sensitivity spectrum detector is arranged in the detection chamber 116 to collect the scattered spectrum for analysis.

[0028] The flow of oil in the detection tube 105 will also drive the force plate 120 to move. This is because the force plate 120 is in an inclined setting in the default state, and there is an angle with the flow direction of the oil. Therefore, the oil will push the force plate 120 to move along the radial direction of the detection tube 105, and initially the force plate 120 moves away from the axial direction of the detection tube 105. At this time, the dial 123 on the force plate 120 will move to contact the second limiting dial plate 134. At this time, the second limiting dial plate 134 and the corresponding protrusion will not swing under the restriction of the second limiting block 135 (the dial 123 is moved to the second limiting block 135). 3), so the multiple second limiting dial plates 134 will drive the dial 123 to rotate (the passive dial plates 133 on the dial 123 interact with the multiple second limiting dial plates 134), the rotation of the dial 123 will drive the active turntable 122 to rotate, the rotation of the active turntable 122 will drive the two levers 124 to rotate, the levers 124 drive the rotation limiting column 121 to rotate, the rotation of the rotation limiting column 121 will drive the force plate 120 to swing, so that the angle between the force plate 120 and the flow direction of the oil body disappears, and the oil body will not push the force plate 120 to move. In this process, the return spring 115 is in a compressed state, and the movement of the limit ring 119 will drive the two spoiler shielding covers 117 on the shielding cover bracket 118 to move, so that the two spoiler shielding covers 117 move from the coaxial position of the detection chamber 116 to the side, so that the oil body enters the detection chamber 116. Then, under the action of the return spring 115, the spoiler shield 117, the shield bracket 118, the limit ring 119 and the force plate 120 are reset (this is because the force plate 120 is no longer subjected to the thrust of the oil body, and the internal parts of the limit ring 119 are isolated from the external transformer oil by a rotary seal). In order to prevent the force plate 120 from swinging under the action of the oil, if the force plate 120 wants to actively swing, it needs to drive the rotation limiting column 121 to swing, and the rotation limiting column 121 will drive the stuck columns 125 on all the inclined surfaces 127 to slide in the limit ring 119. The locking column 125 is movable, and since the locking column 125 is symmetrically arranged, no matter in which direction the force-bearing plate 120 swings, there will always be a locking column 125 that is moved in the direction away from the straight surface 128 by the friction force of the inner wall of the limiting ring 119. At this time, the inclined surface 127 and the limiting ring 119 will squeeze the locking column 125, so that the two are stuck (when the active turntable 122 drives the lever 124 to move, the lever 124 will move the stuck locking column 125, that is, the squeezed locking column 125, towards the direction close to the straight surface 128, so it will not get stuck).

[0029] Under the action of the reset spring 115, the force plate 120 is quickly reset. During this process, the dial 123 will frequently contact the second limit dial plate 134. At this time, the protrusion on the second limit dial plate 134 will separate from the second limit block 135, allowing the second limit dial plate 134 to swing on the control support beam 114, thereby preventing the second limit dial plate 134 from limiting the rotation of the passive dial plate 133 (dial 123). When the dial 123 moves to the position of the first limit dial plate 131, the passive dial plate 133 will squeeze the first limit dial plate 131. At this time, the protrusion on the first limit dial plate 131 will contact the first limit The control block 132 squeezes and prevents the first limiting plate 131 from swinging, thereby limiting the rotation of the passive plate 133 and the dial 123, and further driving the force plate 120 to swing. After the force plate 120 swings, it will be thrust by the flowing oil body, and then continue to move in the direction away from the axis of the detection tube 105. At this time, the protrusion on the first limiting plate 131 is separated from the first limiting block 132, thereby preventing the first limiting plate 131 from limiting the rotation of the passive plate 133 and the dial 123. At this time, the force plate 120 will not rotate until the passive plate 133 contacts the second limiting plate 134 again.

[0030] By repeating the above steps, the detection chamber 116 can intermittently detect the compressor oil in a static state, thereby measuring the furfural components in the compressor oil at different positions.

Claims

1. An optical detection system for furfural in transformer oil, characterized in that: It comprises an oil inlet pipe (101), a plurality of spiral plates (103) are fixed on the inner wall of the oil inlet pipe (101), a flow divider (102) coaxially arranged with the oil inlet pipe (101) is fixed on one end of the spiral plate (103), and an oil inlet gap is arranged between the inner wall of the oil inlet pipe (101) and the flow divider (102); Flanges (130) and connecting pipe rings (104) are fixed at both ends of the oil inlet pipe (101), wherein a separation pipe (107) is fixed on the connecting pipe ring (104), a detection pipe (105) is fixed to the inner wall of the separation pipe (107) via a plurality of reinforcing plates (108), an auxiliary fan (106) is rotatably provided at one end of the detection pipe (105) close to the oil inlet pipe (101), and a motor (109) is fixed to the axial center position of the detection pipe (105) via a plurality of motor support plates (110); Four detection support rods (113) and a control support beam (114) are fixed between two adjacent motor support plates (110), wherein a detection unit is fixed on the four detection support rods (113) for detecting furfural in the compressor oil.

2. The optical detection system for furfural in transformer oil according to claim 1, characterized in that: A turbine bracket (112) is fixed on the output shaft of the motor (109), a driving turbine (111) is fixed on the turbine bracket (112), the driving turbine (111) is rotatably matched with an end of the detection tube (105) away from the spiral plate (103), and an auxiliary fan (106) is also fixed on the output shaft of the motor (109); An oil discharge pipe (129) and a flange (130) are respectively fixed to the separation pipe (107) and the oil inlet pipe (101).

3. The optical detection system for furfural in transformer oil according to claim 2, characterized in that: The detection part comprises a detection chamber (116) fixedly matched with the detection support rod (113), and two ends of the detection chamber (116) are contacted and slidably matched with two symmetrically arranged spoiler shielding covers (117), and the two spoiler shielding covers (117) are used to block the two ends of the detection chamber (116); The two spoiler shielding covers (117) are both fixed on a shielding cover bracket (118), the shielding cover bracket (118) is slidably arranged on two of the detection support rods (113), and a return spring (115) is arranged around the two detection support rods (113), and the two ends of the return spring (115) are fixed to the shielding cover bracket (118) and the inner wall of the detection tube (105); A tunable laser light source is arranged inside the detection chamber (116) to illuminate the stationary oil body in the detection chamber (116), and a spectrum detector is arranged in the detection chamber (116) to collect the scattered spectrum.

4. The optical detection system for furfural in transformer oil according to claim 3, characterized in that: A limiting cylindrical ring (119) is fixed on the shielding cover bracket (118), a force bearing plate (120) is rotatably provided on the limiting cylindrical ring (119), a rotation limiting column (121) is rotatably provided on the inner wall of the limiting cylindrical ring (119), and the rotation limiting column (121) and the limiting cylindrical ring (119) are fixedly and synchronously driven via a rotating shaft; A clamping groove is provided on the rotation limiting column (121) in a symmetrical layout, and the clamping groove comprises two symmetrically arranged inclined surfaces (127) and a straight surface (128), wherein the inclined surfaces (127) and the straight surface (128) are perpendicular to each other.

5. The optical detection system for furfural in transformer oil according to claim 4, characterized in that: A locking column (125) is frictionally slidably disposed between the inclined surface (127) and the inner wall of the limiting sleeve ring (119), and an elastic sheet (126) is elastically connected between the locking column (125) and the straight surface (128); a lever (124) is disposed in contact with the two locking columns (125) in each engaging groove, and the two levers (124) are fixed on the active rotating disk (122), the active rotating disk (122) and the limiting sleeve ring (119) are rotationally matched, and the active rotating disk (122) and the limiting sleeve ring (119) cannot move axially.

6. The optical detection system for furfural in transformer oil according to claim 5, characterized in that: A dial (123) is coaxially fixed on the active rotating disk (122), and a plurality of passive dial plates (133) are arranged in a circular array on the circumferential surface of the dial (123); a plurality of first limiting dial plates (131) and a plurality of second limiting dial plates (134) are arranged in a linear array at a middle position and one end of the control support beam (114), respectively, and all the first limiting dial plates (131) and the second limiting dial plates (134) are in contact with and cooperate with the passive dial plates (133) to drive the dial (123) to rotate.

7. The optical detection system for furfural in transformer oil according to claim 6, characterized in that: There are at least six first limiting plates (131) and at least six second limiting plates (134), and all the first limiting plates (131) and the second limiting plates (134) are rotatably matched with the control support beam (114), and a torsion spring is provided at the rotational connection between the first limiting plates (131) and the second limiting plates (134) and the control support beam (114), and all the first limiting plates (131) and the second limiting plates (134) are provided with a protrusion at one end away from the passive plate (133).

8. The optical detection system for furfural in transformer oil according to claim 7, characterized in that: A first limiting block (132) is fixedly arranged at a position of each protrusion of the first limiting dial plate (131) on the control support beam (114), and the first limiting block (132) contacts and cooperates with a protrusion on the first limiting dial plate (131); a second limiting block (135) is fixedly arranged at a position of the second limiting dial plate (134) on the control support beam (114), and the second limiting block (135) contacts and cooperates with a protrusion on the second limiting dial plate (134); the second limiting block (135) is located on a side of the protrusion of the second limiting dial plate (134) close to the spoiler shield (117), and the first limiting block (132) is located on a side of the protrusion of the first limiting dial plate (131) away from the spoiler shield (117).

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