CN218376874U - Roots vacuum pump - Google Patents
Roots vacuum pump Download PDFInfo
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- CN218376874U CN218376874U CN202222599685.9U CN202222599685U CN218376874U CN 218376874 U CN218376874 U CN 218376874U CN 202222599685 U CN202222599685 U CN 202222599685U CN 218376874 U CN218376874 U CN 218376874U
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Abstract
The utility model relates to a vacuum pump body technical field particularly, relates to a roots vacuum pump. The Roots vacuum pump comprises a cylinder body, a first rotor and a second rotor; the cylinder body is provided with a cylinder chamber, an inlet, an outlet and at least two conduction bypasses; the first rotor and the second rotor are both rotatably arranged in the cylinder chamber; the inlet and the outlet are distributed at two ends of the cylinder body and are communicated with the cylinder chamber; at least two bypass ducts are used to guide the air flow at the outlet towards the inlet. The roots vacuum pump can guide the gas flow at the outlet to the inlet through one or more guide outlets in at least two conduction bypasses in the operation process, and then can guide the compressed gas which is discharged from the outlet and is not processed by the backing pump to the inlet, thereby avoiding the damage of a motor caused by overlarge pressure, and simultaneously continuously operating the roots pump and the backing pump at the same time, adjusting the discharge speed, improving the operability of the pump body and being suitable for operation under the condition of multiple pumping speeds.
Description
Technical Field
The utility model relates to a vacuum pump body technical field particularly, relates to a roots vacuum pump.
Background
The roots vacuum pump is a positive displacement vacuum pump which moves gas by means of a pair of rotors in a pump cavity synchronously and through the pushing action of reverse rotation, so as to realize air suction, and is evolved from a roots blower. The method is widely applied in the industrial fields of petroleum, chemical industry, metallurgy, textile and the like.
When an exhaust port of the conventional Roots vacuum pump is at a specified pressure, a bypass valve is in a closed state; when the pressure of the exhaust port exceeds the specified pressure, the valve of the bypass valve is automatically pushed open, so that the compressed gas which is not processed by the backing pump is discharged, and the damage of the motor caused by overlarge pressure is avoided. By adopting the design, the roots pump and the backing pump can be continuously operated at the same time, but the set discharge speed can be maintained, the operability is poor, and the device is not suitable for operation under the condition of multiple pumping speeds.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a roots vacuum pump can avoid leading to the motor impaired because of pressure is too big, is making roots pump and backing pump continuous operation simultaneously moreover in, adjustable discharge velocity improves the maneuverability of the pump body from this to be applicable to the operation under the condition of many pump speeds.
The embodiment of the utility model is realized like this:
the utility model provides a Roots vacuum pump, which comprises a cylinder body, a first rotor and a second rotor;
the cylinder body is provided with a cylinder chamber, an inlet, an outlet and at least two conduction bypasses;
the first rotor and the second rotor are both rotatably arranged in the cylinder chamber; the inlet and the outlet are distributed at two ends of the cylinder body and are communicated with the cylinder chamber;
at least two bypass ducts are used to guide the air flow at the outlet towards the inlet.
This application is through the setting that at least two switched on the bypass, can be at the in-process of roots vacuum pump operation, the gaseous current that leads the exit through at least two one or more in the bypass of switching on leads the exit to the entry flows, and then can lead the entrance with the exhaust compressed gas of being handled by the backing pump in exit, and then avoided leading to the motor impaired because of the pressure is too big, and when making roots pump and backing pump continuous operation simultaneously, adjustable exhaust speed improves the maneuverability of the pump body from this, and be applicable to the operation under the condition of many pumping speeds.
In an alternative embodiment, the at least two conduction bypasses include a first conduction bypass and a second conduction bypass;
the pressure difference between the inlet and the outlet is a first pressure difference, the pressure difference between the first conduction bypass and the outlet is a second pressure difference, and the pressure difference between the second conduction bypass and the outlet is a third pressure difference; when the second pressure difference is smaller than the first pressure difference and the third pressure difference, the first conduction bypass communicates the outlet with the inlet; the second bypass connects the outlet to the inlet when the third pressure differential is less than the first pressure differential.
The air flow at the outlet can be guided to flow to the inlet through the first conduction bypass when the second pressure difference is smaller than the first pressure difference and the third pressure difference by adopting the arrangement mode of the first conduction bypass and the second conduction bypass; the second bypass is capable of guiding the airflow at the outlet to the inlet when the third pressure difference is smaller than the first pressure difference; and the compressed gas which is discharged from the outlet and is not processed by the backing pump can be guided to the inlet, so that the damage of the motor caused by overlarge pressure is avoided.
In an alternative embodiment, a first valve body is arranged in the first conduction bypass;
the first valve body is used for conducting the first conduction bypass when the second pressure difference is smaller than the first pressure difference and the third pressure difference;
a second valve body is arranged in the second conduction bypass; the second valve body is used for conducting the second conducting bypass when the third pressure difference is smaller than the first pressure difference.
This application can be according to the first conducting state who switches on bypass and export and entry of second pressure differential and the relation adjustment of first pressure differential through the setting of first valve body and second valve body, and in the same way, the second switches on the conducting state of bypass and export and entry through the relation adjustment of third pressure differential and first pressure differential.
In an alternative embodiment, the first valve body and the second valve body are both pressure regulating valves.
What this application adopted is that set up first valve body and second valve body into pressure regulating valve's mode, can guide the compressed gas who is not handled by the backing pump of exit exhaust to the entrance in good time according to the pressure differential relation, and then avoided leading to the motor impaired because of pressure is too big.
In an alternative embodiment, the first conduction bypass includes a first end and a second end, the first end communicating with the inlet and the second end communicating with the outlet.
This application is setting up the first bypass that switches on, for making the first bypass that switches on can switch on export and entry, so adopt make the first end and the entry intercommunication of the first bypass that switches on, its second end and export intercommunication.
In an alternative embodiment, the first valve body is disposed at the first end.
This application is when setting up first valve body, what adopt is that to set up first valve body in the mode of first end, and then makes the first one end that switches on the bypass and be close to the export keep the state of normal open to avoid appearing the condition of backflowing.
In an alternative embodiment, the second conduction bypass includes a third end and a fourth end, the third end communicating with the inlet port and the fourth end communicating with the outlet port.
This application is when setting up the second and leading to the bypass, for making the second to lead to the bypass and can lead to export and entry, so adopt to make the second lead to the third end and the entry intercommunication of bypass, its fourth end and export intercommunication.
In an alternative embodiment, the second valve body is disposed at the third end.
This application is when setting up the second valve body, what adopt is that to set up the second valve body in the mode of third end, and then makes the second switch on the bypass and is close to the one end of export and keep the state of normal open to avoid appearing the condition of backflowing.
In an optional embodiment, the cylinder body is further provided with a first air guide cavity and a second air guide cavity;
the first air guide cavity and the second air guide cavity are communicated with the cylinder chamber;
the inlet, the first end and the third end are communicated with the first air guide cavity; the outlet, the second end and the fourth end are communicated with the second air guide cavity.
When the cylinder body is arranged, the first air guide cavity is arranged so that the inlet, the first end and the third end are communicated with the cylinder chamber conveniently, and the inlet, the first end and the third end are communicated with the first air guide cavity; similarly, a second air guide cavity is arranged, and the outlet, the second end and the fourth end are communicated with the second air guide cavity.
In an alternative embodiment, the direction of rotation of the first rotor is opposite to the direction of rotation of the second rotor.
In the process that the first rotor and the second rotor rotate in the cylinder chamber, the rotating directions of the first rotor and the second rotor are opposite, and then the gas is moved through the pushing and pressing action of the reverse rotation of the first rotor and the second rotor, so that the suction is realized.
The utility model discloses beneficial effect includes:
the Roots vacuum pump comprises a cylinder body, a first rotor and a second rotor; the cylinder body is provided with a cylinder chamber, an inlet, an outlet and at least two conduction bypasses; the first rotor and the second rotor are both rotatably arranged in the cylinder chamber; the inlet and the outlet are distributed at two ends of the cylinder body and are communicated with the cylinder chamber; at least two bypass ducts are used to guide the air flow at the outlet towards the inlet. The roots vacuum pump can discharge compressed gas which is not processed by the backing pump, avoids damage to a motor caused by overlarge pressure, and can adjust the discharge speed while continuously operating the roots pump and the backing pump at the same time, thereby improving the operability of the pump body and being suitable for operation under the condition of multiple pumping speeds.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a schematic structural diagram of a roots vacuum pump in an embodiment of the present invention.
The figure is 200-Roots vacuum pump; 210-cylinder body; 220-a first rotor; 230-a second rotor; 211-cylinder chamber; 212-an inlet; 213-an outlet; 214-a first conduction bypass; 215-second conduction bypass; 216 — a first valve body; 217-a second valve body; 218-a first end; 219-a second end; 241-a third end; 242-a fourth end; 243-first air conducting cavity; 244-second conductive cavity.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the position or positional relationship based on the position or positional relationship shown in the drawings, or the position or positional relationship which is usually placed when the product of the present invention is used, and are only for convenience of description and simplification of the description, but do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.
Furthermore, the terms "horizontal", "vertical" and the like do not imply that the components are required to be absolutely horizontal or pendant, but rather may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.
In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Referring to fig. 1, the present embodiment provides a roots vacuum pump 200, where the roots vacuum pump 200 includes a cylinder block 210, a first rotor 220 and a second rotor 230;
the cylinder block 210 is provided with a cylinder chamber 211, an inlet 212, an outlet 213 and at least two conduction bypasses;
the first rotor 220 and the second rotor 230 are both rotatably disposed in the cylinder chamber 211; the inlet 212 and the outlet 213 are distributed at two ends of the cylinder 210 and are both communicated with the cylinder chamber 211;
at least two bypass bypasses are used to direct the airflow at the outlet 213 towards the inlet 212.
Referring to fig. 1, the roots vacuum pump 200 operates according to the following principle:
the roots vacuum pump 200 includes a cylinder block 210, a first rotor 220 and a second rotor 230; wherein, the cylinder 210 is provided with at least two conduction bypasses; when the first rotor 220 and the second rotor 230 rotate in the cylinder chamber 211, so that the gas enters the cylinder chamber 211 from the inlet 212, is compressed in the cylinder chamber 211 and then is led out from the outlet 213, in the process, the gas flow at the outlet 213 can be led to the inlet 212 through one or more of at least two conducting bypasses;
thus, the roots vacuum pump 200 can guide the compressed gas discharged from the outlet 213 of the roots vacuum pump 200 and not treated by the backing pump to the inlet 212 by the gas guiding function of one or more of the at least two conducting bypasses, thereby preventing the motor from being damaged due to excessive pressure, and the exhaust speed can be adjusted while the roots pump and the backing pump are continuously operated at the same time, thereby improving the operability of the pump body and being suitable for operation under the condition of multiple pumping speeds.
Further, in the present embodiment, the at least two conduction bypasses including the first conduction bypass 214 and the second conduction bypass 215 are taken as an example for explanation, and when the first conduction bypass 214 and the second conduction bypass 215 are provided, the conduction conditions of the first conduction bypass 214 and the second conduction bypass 215 are different according to the pressure in the first conduction bypass 214 and the second conduction bypass 215 and the pressure at the outlet 213 and the inlet 212;
specifically, the difference between the pressure at the inlet 212 and the pressure at the outlet 213 is a first pressure difference, the difference between the pressure at the first conduction bypass 214 and the pressure at the outlet 213 is a second pressure difference, and the difference between the pressure at the second conduction bypass 215 and the pressure at the outlet 213 is a third pressure difference;
when the second pressure difference is smaller than the first pressure difference and the third pressure difference, the first conduction bypass 214 communicates the outlet 213 with the inlet 212;
when the third pressure difference is less than the first pressure difference, the second conduction bypass 215 communicates the outlet 213 with the inlet 212.
Thus, with such an arrangement, the gas flow at the outlet 213 can be guided to the inlet 212 by one or more of the first and second conducting bypasses 214 and 215 under different pressure adjustments, and the compressed gas discharged from the outlet 213 and not processed by the backing pump can be guided to the inlet 212, thereby preventing damage to the motor due to excessive pressure.
Based on the above, referring to fig. 1, in the present embodiment, in order to enable the first conduction bypass 214 to be in a conduction state under the above conditions, a first valve body 216 is disposed in the first conduction bypass 214; the first valve body 216 is configured to open the first opening bypass 214 when the second pressure difference is smaller than the first pressure difference and the third pressure difference;
similarly, a second valve body 217 is arranged in the second conduction bypass 215; the second valve body 217 is configured to conduct the second conduction bypass 215 when the third pressure difference is smaller than the first pressure difference.
Accordingly, the first valve element 216 and the second valve element 217 are provided, whereby the communication state between the first communication bypass 214 and the outlet 213 and the inlet 212 can be adjusted according to the pressure difference between the first communication bypass 214 and the outlet 213, and similarly, the communication state between the second communication bypass 215 and the outlet 213 and the inlet 212 can be adjusted by the pressure difference between the second communication bypass 215 and the outlet 213.
Referring to fig. 1, in the present embodiment, a manner of setting the first valve body 216 and the second valve body 217 as pressure regulating valves is adopted to adjust the conduction states of the first conduction bypass 214, the outlet 213 and the inlet 212 according to the pressure difference between the first conduction bypass 214 and the outlet 213, and adjust the conduction states of the second conduction bypass 215, the outlet 213 and the inlet 212 according to the pressure difference between the second conduction bypass 215 and the outlet 213, so that the compressed gas discharged from the outlet 213 and not processed by the backing pump can be guided to the inlet 212 at a proper time according to the pressure difference relationship between the first conduction bypass 214, the second conduction bypass 215 and the outlet 213, thereby preventing the motor from being damaged due to an excessive pressure.
Based on the above-mentioned structure, referring to fig. 1, in the present embodiment, to facilitate the installation of the first valve body 216 and the second valve body 217, the first conduction bypass 214 includes a first end 218 and a second end 219, the first end 218 is communicated with the inlet 212, the second end 219 is communicated with the outlet 213, and the first valve body 216 is disposed at the first end 218.
That is, when the first conduction bypass 214 is provided, in order to allow the first conduction bypass 214 to communicate the outlet 213 with the inlet 212, it is adopted that the first end 218 of the first conduction bypass 214 communicates with the inlet 212 and the second end 219 communicates with the outlet 213. When the first valve body 216 is provided, the first valve body 216 is provided at the first end 218, and the end of the first conduction bypass 214 connected to the outlet 213 is kept in a normally open state to avoid the backflow.
Similarly, when the second conduction bypass 215 is provided, the third end 241 of the second conduction bypass 215 is communicated with the inlet 212 and the fourth end 242 is communicated with the outlet 213 so that the outlet 213 and the inlet 212 can be communicated with each other by the second conduction bypass 215. And the second valve body 217 is disposed at the third end 241, so that the end of the second conduction bypass 215 connected to the outlet 213 is kept in a normally open state to prevent a backflow.
In summary, referring to FIG. 1, the inlet 212 of the Roots vacuum pump 200 has a pressure P a The pressure at the outlet 213, i.e. at the inlet end of the backing pump, is P v The pressure of the first bypass 214 near the outlet 213 is P 1 The pressure of the second bypass 215 near the outlet 213 is P 2 (ii) a The simultaneous continuous operation of the Roots vacuum pump 200 and the backing pump can be maintained when starting at atmospheric pressure by adjusting the allowable pressure difference of the Roots vacuum pump 200, i.e., the first pressure difference Δ P between the gas pressure at the pump inlet 212 and the pressure at the outlet 213; since the exhaust rate of the roots vacuum pump 200 is 5 to 10 times faster than the exhaust rate of the backing pump connected to the pump, in the present embodiment, when the two pumps are operated simultaneously, more gas exhausted by the roots vacuum pump 200 than the backing pump thereof will be introduced into the first conducting bypass 214 and the second conducting bypass 215; as known from "the model selection technique of the vacuum pump", during the conduction of the first conduction bypass 214 and the second conduction bypass 215, the pumping speed of the roots pump is:
wherein, in the formula: s V The pumping speed of the backing pump is set; p V Outlet 213 pressure; p A Is the inlet 212 pressure; Δ P is the first pressure difference of the Roots vacuum pump 200, Δ P = P v -P A ；
As can be seen from equation (1-1), the pumping speed S of the Roots vacuum pump 200 is a function of the pressure P at the inlet 212 A The voltage drops and increases, so that the starting time can be shortened.
Outside of it, the second pressure difference is Δ P 1 The third pressure difference is Δ P 2 (ii) a A second pressure difference Δ P between the pressure in the first bypass passage 214 and the outlet 213 of the ROOTS vacuum pump 200 1 Is less than the allowable pressure difference delta P of the Roots vacuum pump 200, and is less than the third pressure difference delta P between the pressure entering the second conductive bypass 215 and the outlet 213 of the Roots vacuum pump 200 2 When (wherein, Δ P) 1 And Δ P 2 Unequal size), the first valve body 216 is unseated and compressed process gas that has not been processed by the backing pump of the roots vacuum pump 200 will be exhausted through the first conductive bypass 214 to maintain simultaneous continuous operation of the roots vacuum pump 200 and the backing pump, at which time the evacuation time of the vessel can be reduced by 30-50% relative to a single conductive bypass. Similarly, when Δ P 1 <ΔP 2 <Δ P, the first bypass 214 and the second bypass 215 are both open, and the compressed gas that has not been processed by the backing pump is discharged; in this state, the air exhaust time of the vacuum container in the rough vacuum state can be shortened by 60-70%; and Δ P<ΔP 1 <ΔP 2 At this time, both the first conduction bypass 214 and the second conduction bypass 215 are in the off state.
Referring to fig. 1, in the present embodiment, when the cylinder 210 is disposed, in order to facilitate the communication between the inlet 212, the first end 218 and the third end 241 and the cylinder chamber 211, a first air guide cavity 243 is disposed, and the inlet 212, the first end 218 and the third end 241 are all communicated with the first air guide cavity 243; similarly, a second air conducting cavity 244 is provided, and the outlet 213, the second end 219 and the fourth end 242 are all communicated with the second air conducting cavity 244.
Further, referring to fig. 1, in the present embodiment, the rotation direction of the first rotor 220 is opposite to the rotation direction of the second rotor 230. That is, while the first rotor 220 and the second rotor 230 rotate in the cylinder chamber 211, the rotation directions thereof are opposite to each other, so that the gas is moved by the pressing action of the relative synchronous rotation to achieve the suction.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A roots vacuum pump which is characterized in that:
the Roots vacuum pump (200) comprises a cylinder body (210), a first rotor (220) and a second rotor (230);
the cylinder body (210) is provided with a cylinder chamber (211), an inlet (212), an outlet (213) and at least two conduction bypasses;
the first rotor (220) and the second rotor (230) are both rotatably arranged in the cylinder chamber (211); the inlet (212) and the outlet (213) are distributed at two ends of the cylinder body (210) and are communicated with the cylinder chamber (211);
the at least two conductance bypasses are each for directing the airflow at the outlet (213) towards the inlet (212).
2. A roots vacuum pump as claimed in claim 1, wherein:
the at least two conduction bypasses include a first conduction bypass (214) and a second conduction bypass (215);
wherein the difference between the pressure at the inlet (212) and the pressure at the outlet (213) is a first pressure difference, the difference between the pressure in the first conducting bypass (214) and the pressure at the outlet (213) is a second pressure difference, and the difference between the pressure in the second conducting bypass (215) and the pressure at the outlet (213) is a third pressure difference; the first conduction bypass (214) communicates the outlet (213) with the inlet (212) when the second pressure difference is less than a first pressure difference and a third pressure difference; the second conduction bypass (215) communicates the outlet (213) with the inlet (212) when the third pressure difference is less than the first pressure difference.
3. A roots vacuum pump according to claim 2, wherein:
a first valve body (216) is arranged in the first conduction bypass (214); the first valve body (216) is used for conducting the first conducting bypass (214) when the second pressure difference is smaller than the first pressure difference and the third pressure difference;
a second valve body (217) is arranged in the second conduction bypass (215); the second valve body (217) is configured to communicate the second communication bypass (215) when the third pressure differential is less than the first pressure differential.
4. A roots vacuum pump according to claim 3, wherein:
the first valve body (216) and the second valve body (217) are both pressure regulating valves.
5. A roots vacuum pump according to claim 3, wherein:
the first conduction bypass (214) includes a first end (218) and a second end (219), the first end (218) communicating with the inlet (212), the second end (219) communicating with the outlet (213).
6. A Roots vacuum pump as claimed in claim 5, wherein:
the first valve body (216) is disposed at the first end (218).
7. A Roots vacuum pump as claimed in claim 5, wherein:
the second conduction bypass (215) includes a third end (241) and a fourth end (242), the third end (241) communicates with the inlet (212), and the fourth end (242) communicates with the outlet (213).
8. A Roots vacuum pump as claimed in claim 7, wherein:
the second valve body (217) is disposed at the third end (241).
9. A Roots vacuum pump as claimed in claim 7, wherein:
the cylinder body (210) is also provided with a first air guide cavity (243) and a second air guide cavity (244);
the first air guide cavity (243) and the second air guide cavity (244) are communicated with the cylinder chamber (211);
the inlet (212), the first end (218) and the third end (241) are all communicated with the first air guide cavity (243); the outlet (213), the second end (219), and the fourth end (242) are all in communication with the second plenum (244).
10. A roots vacuum pump according to any one of claims 1-9, wherein:
the first rotor (220) rotates in a direction opposite to that of the second rotor (230).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222599685.9U CN218376874U (en) | 2022-09-29 | 2022-09-29 | Roots vacuum pump |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222599685.9U CN218376874U (en) | 2022-09-29 | 2022-09-29 | Roots vacuum pump |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218376874U true CN218376874U (en) | 2023-01-24 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202222599685.9U Active CN218376874U (en) | 2022-09-29 | 2022-09-29 | Roots vacuum pump |
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| Country | Link |
|---|---|
| CN (1) | CN218376874U (en) |
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2022
- 2022-09-29 CN CN202222599685.9U patent/CN218376874U/en active Active
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