CN215917197U - Online quick detection device of high concentration water and electricity grit waste water SS concentration - Google Patents

Abstract

The utility model discloses an online rapid detection device for SS concentration of high-concentration hydroelectric sandstone wastewater, which comprises a dilution pool, a backwater constant volume device and a sandstone wastewater constant container, wherein the lower parts of the backwater constant volume device and the sandstone wastewater constant volume device are respectively provided with a water outlet pipe with a solenoid valve and respectively extend into the dilution pool, the dilution pool is also provided with a stirring device, the lower part of the dilution pool is provided with a mechanical vibration device, and the side wall of the dilution pool, which is close to the bottom, is provided with an emptying pipe with the solenoid valve; the device comprises a dilution tank, a suspension concentration meter host and a suspension concentration meter, wherein the dilution tank is internally provided with a suspension concentration meter sensor; this device is through accurate control return water and grit waste water proportion, guarantees good dilution effect, further guarantees the mixed effect of return water and grit waste water through mechanical stirring and mechanical vibration compound mode, and then guarantees good dilution effect.

Description

Online quick detection device of high concentration water and electricity grit waste water SS concentration

Technical Field

The utility model relates to the technical field of high-concentration wastewater online detection, in particular to an online rapid detection device for SS concentration of high-concentration hydroelectric sandstone wastewater.

Background

A large amount of sandstone aggregate is needed in the construction of hydropower stations, a large amount of washing wastewater is generated in the production process of the sandstone aggregate, and the concentration of Suspended Solids (SS) is extremely high and can reach 10000 mg/L-180000 mg/L. The SS concentration of the common sandstone wastewater in the actual engineering construction is usually more than 60000 mg/L. If the waste water is directly discharged, serious ecological environment damage is caused. The existing mature sandstone wastewater treatment means adopts a flocculation precipitation mode, and the SS concentration in the wastewater is reduced to below 70mg/L through chemical adding treatment, so that the discharge requirement is met. In actual production, the SS concentration of the sandstone wastewater is in a fluctuation state due to the change of factors such as construction progress, aggregate quality and the like, and in order to ensure that the effluent quality reaches the standard and excessive addition is avoided, the addition amount of the flocculating agent needs to be adjusted in real time according to the SS concentration of the wastewater. However, most of the existing hydropower stations still adopt a rough mode of adjusting the dosage according to the experience and visual identification of workers, the efficiency is low, errors are easily caused, and the effluent is not up to standard or the medicament is wasted, and the cost is increased. There is therefore a need to replace traditional manual identification with advanced on-line rapid electronic detection instruments.

To the higher characteristics of water and electricity grit system SS concentration, need be equipped with the detector that can high SS concentration of on-line measuring. The detection range of the imported instrument with the highest detection range in the market at present reaches 1-500000 mg/L, but the product is expensive, has high maintenance requirements and is not suitable for a sandstone aggregate wastewater system in cost. The price of the existing domestic instrument is proper, but the detection range can only reach 1-120000 mg/L to the maximum extent. And the detection accuracy of the instrument is only +/-5% under a large range, so that all the conditions possibly occurring in the sandstone wastewater are difficult to deal with.

Chinese utility model patent (publication No. CN209589637U) discloses in 2019 a high concentration waste water on-line detector water inlet dilution device, decide the container and decide the container with the running water including waste water, waste water constant volume ware top connect and be equipped with the waste pipe, be equipped with solenoid valve one on the waste pipe, the running water decide the container top and connect and be equipped with the inlet tube, be equipped with solenoid valve two on the inlet tube, waste water decide the container and the running water decide the container and connect through drain pipe one and drain pipe two respectively and dilute the section of thick bamboo, be equipped with solenoid valve three on the drain pipe one, be equipped with solenoid valve four on the drain pipe two, dilute the section of thick bamboo on be equipped with agitating unit, one side of diluting the section of thick bamboo pass through the sampling tube and connect on-line detector system, the sampling tube on be equipped with solenoid valve five and intake pump, the bottom of diluting the section of thick bamboo be equipped with evacuation pipe, be equipped with solenoid valve six on the evacuation pipe. The device can automated control, carries out the on-line measuring of high concentration waste water, but when handling the solid useless that contains the grit, the stirring dispersion effect is not good, and the grit blocks up the evacuation pipe easily moreover, is difficult for wasing. In addition, this device requires a sample to be taken from a dilution cylinder for detection, and thus cannot directly measure the concentration.

Disclosure of Invention

The utility model aims to provide an online rapid detection device for SS concentration of high-concentration hydroelectric sandstone wastewater, aiming at the problems in the prior art.

In order to achieve the purpose, the utility model adopts the technical scheme that:

the device comprises a dilution pool, a return water volume fixing device and a sandstone wastewater volume fixing container, wherein the return water volume fixing device and the sandstone wastewater volume fixing container are arranged above the dilution pool, a water outlet pipe with an electromagnetic valve is respectively arranged below the return water volume fixing container and the sandstone wastewater volume fixing container and respectively extend into the dilution pool, a stirring device is further arranged on the dilution pool, a mechanical vibration device is arranged below the dilution pool, and a drain pipe with the electromagnetic valve is arranged on the side wall, close to the bottom, of the dilution pool; still be equipped with the suspended solid concentration meter sensor in the dilution pond, the suspended solid concentration meter sensor passes through the cable and sets up the outside suspended solid concentration meter host computer of dilution pond is connected.

This online short-term test device guarantees good dilution effect through accurate control return water and grit waste water proportion, further guarantees the mixed effect of return water and grit waste water through mechanical stirring and mechanical vibration compound mode, and then guarantees good dilution effect.

This online short-term test device can realize that the grit of low cost, high accuracy measurement high concentration washes waste water, can realize the measurement of arbitrary high concentration waste water through adjusting the dilution multiple in theory, has solved current concentration detection instrument because the range precision is unsatisfactory or the cost reason such as too high can't match the difficult point of use with grit waste water system. The application scene is wide, and the method is suitable for all places with single materials.

And the mechanical vibration device is arranged below the dilution tank, the mixing effect of the backwater and the sand and stone wastewater in the dilution tank is further enhanced through the vibration effect, and meanwhile, the inaccurate test result and blockage of the emptying pipe caused by the natural sedimentation of SS are avoided.

Through suspended solid concentration meter sensor can directly acquire the concentration of mixing back solution, measures both conveniently also accurate, during the use suspended solid concentration meter sensor needs the submergence below the waste water liquid level to realize diluting the real-time detection of back waste water.

The detection method of the online rapid detection device is carried out according to the following steps:

firstly, quantitatively pumping the wastewater and the return water into a sand and stone wastewater fixed container and a return water fixed container respectively according to the required dilution multiple set by the high-concentration sand and stone wastewater, and controlling the water inflow by a volumetric meter;

opening electromagnetic valves below the volume settlers to add the wastewater and the backwater into the dilution tank, simultaneously opening the stirring device and the mechanical vibration device, uniformly mixing, reading readings on a host of the suspended matter concentration meter, and calculating the actual concentration of the sandstone wastewater SS according to the dilution times;

the sand and stone wastewater SS actual concentration calculation formula is as follows: c is C1/n.

Wherein C is the actual concentration of the sandstone wastewater SS, C1 is the concentration of diluted wastewater tested by an online suspended matter concentration meter, and n is the dilution multiple of the sandstone wastewater.

And thirdly, opening the emptying pipe to empty the diluted wastewater after the test is finished, and independently pumping the wastewater into backwater to clean the dilution tank. During cleaning, the stirring device and the mechanical vibration device are both in a working state, and the dilution tank is emptied after cleaning to wait for the next measurement; the detection interval time may be set by a writing program.

The return water obtained by treating the diluted wastewater is used as a diluent, the water quality standard of the return water is set to be not more than 70mg/L, the concentration of the sandstone wastewater is 60000mg/L for example, and the measurement error caused by the difference of pure water or the return water can be controlled to be 1 percent, so that the actual requirement of precision is met. Therefore, the backwater is selected as the diluent in consideration of the water-saving requirement of the sand system.

Further, mechanical vibration device is for setting up one or more's combination in dull and stereotyped, the vibrting spear of a plurality of parallel arrangements and the ultrasonic vibration device of vibration of dilution pond below, the vibration is dull and stereotyped or the vibrting spear all connects the drive through vibrating motor, the ultrasonic vibration device passes through ultrasonic drive power and connects the drive. The vibration motor drives the vibration flat plate or the vibration rod to vibrate, so that the dilution tank vibrates; when the vibrating spear is adopted, the vibrating motor can be arranged in the vibrating spear. The power supply of the ultrasonic driving device drives the ultrasonic vibration device to generate ultrasonic waves, so that the mixed wastewater in the diluting tank is vibrated.

Furthermore, the vibration frequency of the vibration flat plate and the vibration rod is more than or equal to 50Hz, and the frequency of the ultrasonic vibration device is 20-40 KHz.

Furthermore, agitating unit is including setting up dilute the agitator motor of pond top, and with the (mixing) shaft that agitator motor is connected, the (mixing) shaft stretches into in the liquid in the dilute pond and be equipped with a plurality of layers of stirring vane on the (mixing) shaft. The stirring shaft and the stirring blades are driven to rotate by the stirring motor, so that backwater and sand and stone wastewater are fully mixed in the dilution tank.

Further, the rotating speed of the stirring device is more than or equal to 200 rpm.

Further, the diluting tank is of a closed structure and is provided with a top plate capable of being opened and closed, and the stirring device is installed in the middle of the top plate; and a plurality of support frames are further arranged above the top plate and used for supporting and fixing the backwater fixed container and the sandstone wastewater fixed container. The provision of the top plate facilitates the mounting and securing of these components.

Furthermore, the support frame includes a plurality of bracing pieces, the one end spiro union of bracing piece is in on the roof, the other end welding has the backup pad of slope, the backup pad butt the container is decided to the return water or the grit waste water decides the outer wall of container, the backup pad with be equipped with the damping pad between the outer wall, play the damping effect, reduce the vibration and decide the negative effects of container to these.

Furthermore, a through hole for the cable to pass through is formed in the top plate, and a wire clamp or a hook is arranged in the through hole. The fastener perhaps setting of hook can be fixed the cable, works as behind the suspended solid concentration meter sensor submergence to reasonable position, can with the cable is fixed, avoids its position at will to change at the measuring in-process.

Furthermore, volumetric meters are respectively arranged in the backwater fixed container and the sandstone wastewater fixed container, and the backwater fixed container and the sandstone wastewater fixed container are respectively connected with a water inlet pipe with an electromagnetic valve; the volumetric meter the solenoid valve agitating unit's agitator motor mechanical oscillation device's drive device (like driving motor or drive power supply etc.) with suspended solid concentration meter sensor all is connected with the PLC controller, the PLC controller can set up in the suspended solid concentration meter host computer, also can independently set up again with the suspended solid concentration meter host computer is connected.

The PLC is a programmable industrial controller, a control program is arranged in the PLC to realize full-automatic control, the control precision is higher, and the operation is simple and convenient.

Furthermore, a clamping groove is formed in the vibrating flat plate, the bottom of the diluting pool is clamped in the clamping groove, and a plurality of limiting blocks are further arranged on the periphery of the clamping groove.

Compared with the prior art, the utility model has the beneficial effects that: 1. the online rapid detection device ensures a good dilution effect by accurately controlling the proportion of the return water and the sandstone wastewater, further ensures the mixing effect of the return water and the sandstone wastewater by a combined mode of mechanical stirring and mechanical vibration, and further ensures the good dilution effect; 2. the online rapid detection device can realize low-cost and high-precision measurement of high-concentration sandstone flushing wastewater, theoretically can realize measurement of any high-concentration wastewater by adjusting the dilution multiple, and solves the problem that the existing concentration detection instrument cannot be matched with a sandstone wastewater system for use due to reasons that the range precision does not meet the requirement or the manufacturing cost is too high and the like; 3. the mechanical vibration device is arranged below the dilution tank, the mixing effect of the backwater and the sand and stone wastewater in the dilution tank is further enhanced through the vibration effect, and meanwhile, the inaccurate test result and the blockage of the emptying pipe caused by the natural sedimentation of SS are avoided; 4. through the cooperation of suspended solid concentration meter sensor and host computer can directly acquire the concentration of mixing back solution, and it is also accurate to measure the convenience.

Drawings

FIG. 1 is an overall schematic diagram of an online rapid detection device for SS concentration of high-concentration hydroelectric sandstone wastewater according to the utility model;

FIG. 2 is a schematic structural view of the stand according to the present invention;

FIG. 3 is a view of the cable fixing structure on the top plate of the diluting pool according to the present invention;

FIG. 4 is a schematic structural view of a vibrating plate under a diluting well according to the present invention;

in the figure: 1. a dilution tank; 101. a top plate; 102. a through hole; 2. a backwater fixed container; 201. a water return outlet pipe; 202. a backwater inlet pipe; 3. a sand and stone waste water container; 301. a sandstone wastewater outlet pipe; 302. a sandstone wastewater inlet pipe; 4. a stirring motor; 5. a stirring shaft; 6. a stirring blade; 7. a vibrating rod; 8. emptying the pipe; 9. a suspended matter concentration meter sensor; 10. a suspended matter concentration meter host; 11. an electromagnetic valve; 12. a capacity meter; 13. a cable; 14. wire clamps; 15. a support bar; 16. a support plate; 17. a vibration damping pad; 18. vibrating the flat plate; 19. a clamping groove; 20. a limiting block; 21. a vibration motor.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "middle", "upper", "lower", "left", "right", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The first embodiment is as follows:

as shown in fig. 1, an online rapid detection device for SS concentration of high-concentration hydroelectric sandstone wastewater comprises a dilution tank 1, a backwater fixed container 2 and a sandstone wastewater fixed container 3 which are arranged above the dilution tank 1, wherein a backwater water outlet pipe 201 with a solenoid valve and a sandstone wastewater water outlet pipe 301 are respectively arranged below the backwater fixed container 2 and the sandstone wastewater fixed container 3 and respectively extend into the dilution tank 1, a stirring device is further arranged on the dilution tank 1, a vibrating bar is arranged below the dilution tank 1, and a drain pipe 8 with a solenoid valve is arranged on the side wall of the dilution tank 1 close to the bottom; still be equipped with suspended solid concentration meter sensor 9 in the dilution pond 1, suspended solid concentration meter sensor 9 passes through cable 13 and sets up the outside suspended solid concentration meter host computer 10 in dilution pond 1 is connected.

This online short-term test device guarantees good dilution effect through accurate control return water and grit waste water proportion, further guarantees the mixed effect of return water and grit waste water through mechanical stirring and mechanical vibration compound mode, and then guarantees good dilution effect.

The vibrating spear 7 is arranged below the dilution tank 1, the mixing effect of the backwater and the sand and stone wastewater in the dilution tank 1 is further enhanced through the vibrating action, and meanwhile, the inaccurate test result and blockage of the emptying pipe caused by SS natural sedimentation are avoided.

Through suspended solid concentration meter sensor 9 can directly acquire the concentration of mixing back solution, measures both conveniently also accurate, during the use suspended solid concentration meter sensor 9 needs the submergence below the waste water liquid level to realize diluting the real-time detection of back waste water.

Furthermore, volumetric meters 12 are respectively arranged in the backwater fixed container 2 and the sandstone wastewater fixed container 3, and the backwater fixed container 2 and the sandstone wastewater fixed container 3 are respectively connected with a backwater water inlet pipe 202 with a solenoid valve and a sandstone wastewater inlet pipe 302; the volume meter 12 the solenoid valve 11 agitating unit's agitator motor with suspended solid concentration meter sensor 9 all is connected with the PLC controller. The PLC is a programmable industrial controller, a control program is arranged in the PLC to realize full-automatic control, the control precision is higher, and the operation is simple and convenient.

Further, agitating unit is including setting up the agitator motor 4 of dilution pond 1 top, and with agitator motor 4 connects (mixing) shaft 5, agitator shaft 5 stretches into in the liquid in dilution pond 1 and be equipped with a plurality of layers of stirring vane 6 on (mixing) shaft 5. The stirring shaft 5 and the stirring blades 6 are driven to rotate by the stirring motor 4, so that the return water and the sandstone wastewater are fully mixed in the dilution tank.

The detection method of the online rapid detection device is carried out according to the following steps:

(1) quantitatively pumping 10ml of wastewater and 90ml of return water into a sand and stone wastewater fixed container and a return water fixed container respectively according to the required dilution multiple of the high-concentration sand and stone wastewater set as 10, and controlling the water inflow by a volumetric meter;

(2) opening electromagnetic valves below the volume settlers to add wastewater and backwater into the dilution tank, and simultaneously opening the stirring device and the vibrating rods, wherein the rotating speed of the stirring device is set to be 200rpm, and the frequency of the vibrating rods is set to be 50 Hz; reading the readings on the suspended matter concentration meter host 10 after uniform mixing and calculating the actual concentration of the sandstone wastewater SS according to the dilution times;

the sand and stone wastewater SS actual concentration calculation formula is as follows: c ═ C₁/10。

Wherein C is the actual concentration of the sandstone wastewater SS, C₁The concentration of the diluted wastewater is tested by an online suspended matter concentration meter, and 10 is the dilution multiple of the sandstone wastewater.

(3) And after the test is finished, opening the emptying pipe to empty the diluted wastewater, and independently pumping the diluted wastewater into 100ml of backwater to clean the dilution tank. During cleaning, the stirring device and the mechanical vibration device are both in a working state, and the dilution tank is emptied after cleaning to wait for the next measurement; the detection interval time may be set by a writing program.

Example two:

this example provides an alternative method of measuring dilution factor.

(1) Quantitatively pumping 10ml of wastewater and 190ml of return water into a sand and stone wastewater fixed container and a return water fixed container respectively according to the required dilution multiple set by the high-concentration sand and stone wastewater of 20, and controlling the water inflow by a volumetric meter;

(2) opening electromagnetic valves below the volume settlers to add wastewater and backwater into the dilution tank, and simultaneously opening the stirring device and the vibrating rods, wherein the rotating speed of the stirring device is set to be 300rpm, and the frequency of the vibrating rods is set to be 80 Hz; reading readings on a host machine of the suspended matter concentration meter after uniform mixing, and calculating the actual concentration of the sandstone wastewater SS according to the dilution times;

the sand and stone wastewater SS actual concentration calculation formula is as follows: c ═ C₁/20。

Wherein C is the actual concentration of the sandstone wastewater SS, C₁The concentration of the diluted wastewater is tested by an online suspended matter concentration meter, and 20 is the dilution multiple of the sandstone wastewater.

(3) And after the test is finished, opening the emptying pipe to empty the diluted wastewater, and independently pumping 200ml of return water to clean the dilution tank. And during cleaning, the stirring device and the mechanical vibration device are both in a working state, and the dilution tank is emptied after cleaning to wait for the next measurement.

Example three:

this example provides a structure of a dilution tank.

As shown in fig. 2, the dilution tank 1 is a rectangular closed structure, the dilution tank 1 has a top plate 101 that can be opened and closed, and the stirring motor 4 is installed in the middle of the top plate 101; a plurality of support frames are further arranged above the top plate 101 and used for supporting and fixing the backwater fixing container 2 and the sandstone wastewater fixing container 3. The top plate 101 is provided to facilitate mounting and securing of these components.

Furthermore, the support frame includes a plurality of bracing pieces 15, the one end spiro union of bracing piece 15 is in on the roof 101, and the welding of the other end has inclined backup pad 16, backup pad 16 butt the outer wall that container 2 was decided to the return water or container 3 was decided to grit waste water, backup pad 16 with be equipped with damping pad 17 between the outer wall, play the damping effect, reduce the negative effects of vibration to these decide the container.

Further, as shown in fig. 3, a through hole 102 for the cable 13 to pass through is formed in the top plate 101, a wire clamp 14 is arranged in the through hole 102, and the wire clamp 14 is an elastic clamp. The setting of fastener 14 can be fixed cable 13, work as behind the suspended solid concentration meter sensor 9 submergence to reasonable position, can with cable 13 is fixed, avoids its position at will to change at the measuring in-process.

Example four:

the present embodiment provides another structure of the mechanical vibration device.

As shown in fig. 4, the mechanical vibration device is a vibration plate 18 disposed below the dilution pool 1, and the vibration plate 18 is connected and driven by a vibration motor 21.

Furthermore, a clamping groove 19 is formed in the vibrating plate 18, the bottom of the diluting pool 1 is clamped in the clamping groove 19, and a plurality of limiting blocks 20 are further arranged on the periphery of the clamping groove 19 to limit the diluting pool 1.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the utility model, the scope of which is defined in the appended claims and their equivalents.

Claims (10)

1. The device comprises a dilution pool, a return water volume fixing device and a sandstone wastewater volume fixing container, wherein the return water volume fixing device and the sandstone wastewater volume fixing container are arranged above the dilution pool, a water outlet pipe with an electromagnetic valve is respectively arranged below the return water volume fixing container and the sandstone wastewater volume fixing container and respectively extend into the dilution pool, and a stirring device is further arranged on the dilution pool; still be equipped with the suspended solid concentration meter sensor in the dilution pond, the suspended solid concentration meter sensor passes through the cable and sets up the outside suspended solid concentration meter host computer of dilution pond is connected.

2. The device for rapidly detecting the SS concentration of the high-concentration hydroelectric sandstone wastewater according to claim 1, wherein the mechanical vibration device is one or more of a vibration flat plate, a plurality of vibration rods arranged in parallel and an ultrasonic vibration device which are arranged below the dilution tank, the vibration flat plate or the vibration rods are connected and driven through a vibration motor, and the ultrasonic vibration device is connected and driven through an ultrasonic driving power supply.

3. The device for online rapid detection of SS concentration of high-concentration hydroelectric sandstone wastewater according to claim 2, wherein the vibration frequency of the vibration plate and the vibration rod is not less than 50Hz, and the frequency of the ultrasonic vibration device is 20-40 KHz.

4. The device for rapidly detecting the SS concentration of the high-concentration hydroelectric sandstone wastewater according to claim 1, wherein the stirring device comprises a stirring motor arranged above the dilution tank and a stirring shaft connected with the stirring motor, and the stirring shaft extends into the liquid in the dilution tank and is provided with a plurality of layers of stirring blades.

5. The device for rapidly detecting the SS concentration of the high-concentration hydroelectric sandstone wastewater according to claim 1 or 4, wherein the rotating speed of the stirring device is more than or equal to 200 rpm.

6. The device for rapidly detecting the SS concentration of the high-concentration hydroelectric sandstone wastewater according to claim 1, wherein the dilution tank is of a closed structure and is provided with a top plate which can be opened and closed, and the stirring device is arranged in the middle of the top plate; and a plurality of support frames are further arranged above the top plate and used for supporting and fixing the backwater fixed container and the sandstone wastewater fixed container.

7. The device for rapidly detecting the SS concentration of the high-concentration hydroelectric sandstone wastewater according to claim 6, wherein the support frame comprises a plurality of support rods, one end of each support rod is screwed on the top plate, the other end of each support rod is welded with an inclined support plate, and the support plates are abutted against the outer walls of the backwater fixed container or the sandstone wastewater fixed container.

8. The device for rapidly detecting the SS concentration of the high-concentration hydroelectric sandstone wastewater according to claim 6, wherein a through hole for the cable to pass through is arranged on the top plate, and a wire clamp or a hook is arranged in the through hole.

9. The device for the on-line rapid detection of the SS concentration of the high-concentration hydroelectric sandstone wastewater according to claim 1, wherein the backwater fixed container and the sandstone wastewater fixed container are respectively provided with a volumetric meter, and are respectively connected with a water inlet pipe with a solenoid valve; the volumetric meter the solenoid valve agitating unit's agitator motor mechanical oscillation device's drive device with the suspended solid concentration meter sensor all is connected with the PLC controller.

10. The device for online rapid detection of SS concentration of high-concentration hydroelectric sandstone wastewater according to claim 2, wherein a clamping groove is arranged on the vibrating plate, the bottom of the diluting pool is clamped in the clamping groove, and a plurality of limiting blocks are arranged on the periphery of the clamping groove.

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