CN215134616U - Anti-backflow extension tube and infusion apparatus - Google Patents

Abstract

The application provides an anti-backflow extension tube and an infusion apparatus, wherein the anti-backflow extension tube comprises a fluid inlet, a fluid outlet and a bypass port, wherein the fluid outlet and the bypass port are communicated with the fluid inlet; an integration channel in communication with the fluid outlet; the fluid inlet and the bypass port can be respectively communicated with the integrated channel, and the liquid medicine can enter the integrated channel through the fluid inlet and the bypass port and is discharged through the fluid outlet; the anti-backflow device comprises a first anti-backflow device, and the first anti-backflow device is arranged in the integrated channel. The anti-backflow extension tube is arranged, so that on one hand, the mixture of the backflow liquid medicine and the blood is prevented from polluting the residual liquid medicine, and the backflow blood is flushed into the blood vessel again through the forward flowing of the liquid in the infusion tube and the extension tube; on the other hand, when different kinds of liquid medicines are added through the side opening, the problem of mutual pollution of the different kinds of liquid medicines is effectively avoided.

Description

Anti-backflow extension tube and infusion apparatus

Technical Field

The application relates to the technical field of medical equipment, in particular to an anti-backflow extension tube and an infusion apparatus.

Background

The venous transfusion technology is widely applied in clinic at present, but in the transfusion process, blood return phenomenon can be generated due to overhigh hand lifting of a transfusing person or increased pressure of upper limbs, and blood can accidentally flow back into a transfusion tube when a patient moves. The blood return phenomenon can be large or small, because the blood that flows back easily produces little clot, then can block up the pinhole and need puncture again, then has the potential danger that forms the thrombus, and the consequence that brings for patient is beyond the limit of thinking, in the infusion in-process, sometimes need simultaneously or intermittently carry multiple liquid medicine, the phenomenon of flowing backwards can appear between many conveyer pipes, the condition of polluting other liquid medicines exists.

CN202277585U anti-reflux blood return infusion set relates to a medical infusion set, and consists of an infusion bottle, an infusion tube and a puncture needle. The lower port of the infusion bottle is connected with an infusion tube, a drip cup is connected in series in the infusion tube, an infusion speed regulator is arranged on the tube, the lower end of the infusion tube is connected with a puncture needle, and the root of the puncture needle is provided with a check valve and is connected with the infusion tube. The check valve is characterized in that a valve seat is arranged in the pipe column, and a floater is arranged at the lower opening of the valve seat. Prevent the device against current among the prior art all sets up in the transfusion system trunk line, however, in actual use, the transfer line that is close to the syringe needle position is owing to link to each other with the syringe needle, so the diameter taper, itself is because the diameter is thinner, just take place the blood return phenomenon easily when the fluid velocity of flow is lower, the valve is prevented against current in this place installation, can further restrict its velocity of flow and flow lower, can solve the blood return problem to a certain extent, but this structure can make fluidic velocity of flow, the flow further reduces, has adverse effect to infusion process.

SUMMERY OF THE UTILITY MODEL

The utility model provides an anti-backflow extension tube and an infusion apparatus, which solve at least one technical problem in the technical problems.

The utility model discloses the technical scheme who adopts does:

in a first aspect, the present application provides an anti-backflow extension tube comprising a fluid inlet, and a fluid outlet and a bypass port in communication with the fluid inlet; an integration channel in communication with the fluid outlet; the fluid inlet and the bypass port can be respectively communicated with the integrated channel, and liquid medicine can enter the integrated channel through the fluid inlet and the bypass port and is discharged through the fluid outlet; the integrated channel is characterized by also comprising an anti-backflow device, wherein the anti-backflow device comprises a first anti-backflow device, and the first anti-backflow device is arranged in the integrated channel; the first anti-backflow device comprises a main body, the main body is integrally cylindrical, one end of the main body is provided with a liquid inlet, and the other end of the main body is provided with a liquid outlet; the cross-sectional area of the liquid inlet is smaller than that of the liquid outlet; the liquid inlet is communicated with the flow limiting hole and the liquid outlet in sequence; the first anti-backflow device further comprises a flow limiting piece, a first connecting part is arranged at the lower part of the liquid inlet, a second connecting part is arranged at the lower part of the flow limiting hole, and the flow limiting piece is fixedly connected with the first connecting part and the second connecting part respectively; the flow limiting cavity is arranged between the liquid inlet and the flow limiting hole; the flow limiting piece comprises a first flow limiting pair and a second flow limiting pair, the first flow limiting pair comprises a first anti-backflow sheet and a second anti-backflow sheet, the first connecting part comprises two oppositely arranged grooves, and at least one part of each of the first anti-backflow sheet and the second anti-backflow sheet is arranged in the two grooves respectively; the second flow limiting pair comprises a third anti-backflow sheet and a fourth anti-backflow sheet, the second connecting part comprises two oppositely arranged grooves, and at least one part of each of the third anti-backflow sheet and the fourth anti-backflow sheet is arranged in the two grooves respectively; the first anti-backflow piece is shorter than the second anti-backflow piece, and the third anti-backflow piece is shorter than the fourth anti-backflow piece.

As a preferred embodiment of the present invention, the anti-backflow extension pipe further comprises a bypass pipe, one end of the bypass pipe is communicated with the integrated channel, and the other end of the bypass pipe is provided with the bypass port; the anti-backflow device further comprises a second anti-backflow device, and the second anti-backflow device is arranged in the bypass pipe.

As a preferred embodiment of the present invention, the first anti-backflow device is disposed downstream of a communication position between the integrated channel and the bypass port in a flow direction of the liquid medicine; or, the first anti-backflow device is arranged at the downstream of the communication position of the integrated channel and the bypass pipe along the flow direction of the liquid medicine.

As a preferred embodiment of the present invention, the flow restriction hole and the liquid outlet are provided with a guide slope therebetween.

As a preferred embodiment of the utility model, inlet department upper portion is provided with first spacing portion, the liquid outlet lower part is provided with the spacing portion of second.

In a second aspect, the utility model also provides an infusion apparatus, including venous transfusion pipe and transfusion needle and as above anti-backflow extension pipe, the fluid entry is linked together with the one end that is close to the transfusion needle of venous transfusion pipe, the fluid outlet with the transfusion needle intercommunication, by-pass port and external liquid medicine source intercommunication.

As a preferred embodiment of the present invention, the infusion needle comprises an infusion needle connecting tube and an infusion needle head; the diameter of the anti-backflow extension pipe is 1.5-3 times of that of the infusion needle connecting pipe, and the diameter of the anti-backflow extension pipe is 0.8-1 times of that of the venous infusion tube.

Since the technical scheme is used, the utility model discloses the beneficial effect who gains does:

1. the anti-backflow extension tube is arranged, so that on one hand, the mixture of the backflow liquid medicine and the blood is prevented from polluting the residual liquid medicine, and the backflow blood is flushed into the blood vessel again through the forward flowing of the liquid in the infusion tube and the extension tube; on the other hand, when different kinds of liquid medicines are added through the side opening, the problem of mutual pollution of the different kinds of liquid medicines is effectively avoided; the arrangement of the integrated channel discharges the liquid medicine through the fluid outlet, thereby being beneficial to improving the anti-backflow effect and ensuring the mixing effect of the liquid medicine, and the stable and safe operation of the infusion process is realized.

2. First anti-reflux device sets up the low reaches in the intercommunication department of integrated channel and by pass port or bypass pipe along liquid medicine flow direction in this application for the pressure of the liquid medicine that comes from transfer line and by pass port or bypass pipe has been concentrated to first anti-reflux device upper reaches, helps promoting the anti-reflux ability of anti-reflux extension pipe.

3. The first anti-backflow device and the second anti-backflow device are cylindrical as a whole, are matched with the inner wall of the extension pipe more tightly, have better sealing effect and avoid liquid leakage and seepage; the cross-sectional area of the liquid inlet is smaller than that of the liquid outlet, so that the liquid medicine pressure at the liquid inlet is larger, and the anti-backflow effect is improved.

4. The length of two anti-backflow pieces in each current-limiting pair of the anti-backflow device is different, and the anti-backflow pieces are overlapped more easily to seal the current-limiting holes and/or the liquid inlet when liquid medicine flows back.

5. When the setting of direction inclined plane makes the liquid medicine take place to flow backwards in this application, the pressure of liquid medicine at first acts on the fixed connection department of anti backflow piece and connecting portion for two anti backflow pieces that the second current-limiting is right overlap more easily and seal the restricted aperture, help promoting anti backflow effect.

6. The relation between anti-backflow extension pipe diameter and vein transfer line diameter and infusion needle connecting pipe diameter makes the fluid resistance in the extension pipe less and can not influence the fluid flow in the transfer line, can realize anti-backflow effect, can guarantee the steady safety of infusion process again and go on.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 is a schematic view of an anti-reflux extension tube according to the present application;

FIG. 2 is a schematic view of another embodiment of an anti-reflux extension tube of the present application;

FIG. 3 is a schematic view of an anti-reflux device according to the present application;

FIG. 4 is a schematic diagram of an exemplary anti-reflux device;

FIG. 5 is a schematic view of an infusion set according to the present application;

fig. 6 is a schematic structural diagram of another infusion set of the present application.

Wherein:

1-anti-reflux extension tube, 11-fluid inlet, 12-fluid outlet, 13-bypass port, 14-bypass tube, 15-integrated channel, 2A-first anti-reflux device, 2B-second anti-reflux device, 20-main body, 21-liquid inlet, 22-flow limiting hole, 23-liquid outlet, 24-flow limiting cavity, 25-first connecting part, 26-second connecting part, 27-guiding inclined plane, 28-first limiting part, 29-second limiting part, 201-first anti-reflux sheet, 202-second anti-reflux sheet, 203-third anti-reflux sheet, 204-fourth anti-reflux sheet, 3-venous transfusion tube, 41-transfusion needle connecting tube, 42-transfusion needle head, and 5-connector.

Detailed Description

In order to more clearly explain the overall concept of the present application, the following detailed description is given by way of example in conjunction with the accompanying drawings.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, however, the present application may be practiced in other ways than those described herein, and therefore the scope of the present application is not limited by the specific embodiments disclosed below.

In addition, in the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", and the like, indicate orientations and positional relationships based on those shown in the drawings, are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

As shown in fig. 1 to 6, the present invention provides an anti-backflow extension pipe 1, which includes a fluid inlet 11, and a fluid outlet 12 and a bypass port 13 communicated with the fluid inlet 11; an integration channel 15, the integration channel 15 being in communication with the fluid outlet 12; the fluid inlet 11 and the bypass port 13 can be respectively communicated with the integrated channel 15, and the liquid medicine can enter the integrated channel 15 through the fluid inlet 11 and the bypass port 13 and be discharged through the fluid outlet 12; the anti-backflow device comprises a first anti-backflow device, and a first anti-backflow device 2A is arranged in the integrated channel 15.

The arrangement of the integrated channel 15 discharges the liquid medicine from the fluid outlet 12, which is beneficial to improving the anti-reflux effect and ensuring the mixing effect of the liquid medicine, and the stable and safe operation of the transfusion process.

It should be understood that the structure of the anti-backflow extension pipe 1 of the present invention is not limited in particular, and may be the structure of fig. 1, the structure of fig. 2, or other structures.

Further, as shown in fig. 1, the anti-backflow extension pipe 1 in the present application further includes a bypass pipe 14, one end of the bypass pipe 14 is communicated with the integrated channel 15, and the other end of the bypass pipe 14 is provided with a bypass port 13; the anti-reflux device further comprises a second anti-reflux device 2B arranged in a second anti-reflux device bypass pipe 14.

The second anti-backflow device 2B in the present application has the same structure as the first anti-backflow device 2A.

On one hand, when the backflow phenomenon occurs, the arrangement of the first backflow device and the second backflow device effectively prevents the liquid medicine and the blood from flowing back through the integrated channel 15 and the bypass pipe 14, prevents the residual liquid medicine in the integrated channel 15 and the bypass pipe 14 from being polluted by the backflow liquid medicine and the blood, and improves the backflow prevention effect; on the other hand, when different types of liquid medicines are added into the infusion tube through the bypass tube 14, the second backflow device is used for regulating and controlling the mixing speed of the liquid medicines in the bypass tube 14, and the mixing effect of the liquid medicines is improved. In addition, under normal conditions, the arrangement of the second backflow device is also beneficial to preventing the liquid medicine in the infusion tube from flowing out through the bypass tube 14 due to the large pressure in the infusion tube, and further ensuring the stable and safe infusion process.

It should be understood that the present invention is not limited to the connection manner and connection structure of the integration passage 15 and the bypass pipe 14, and as a preferred embodiment of the present invention, the bypass pipe 14 and the integration passage 15 are integrally formed as shown in fig. 1. Of course, the connection mode can also be a threaded connection, a snap connection and the like.

The bypass pipe 14 and the integrated channel 15 are integrally formed, the structure is simple, the processing is convenient, a connecting piece is not additionally arranged between the bypass pipe 14 and the integrated channel 15, and the cost is saved. Meanwhile, the bypass pipe 14 and the integrated channel 15 are integrally formed, so that the tightness between the bypass pipe 14 and the integrated channel 15 can be ensured, and external bacteria and the like can be prevented from entering the bypass pipe 14 and/or the integrated channel 15 to pollute the liquid medicine.

Further, as shown in fig. 1 and 2, the first anti-backflow device 2A is disposed downstream of the communication of the integrated passage 15 and the bypass port 13 in the flow direction of the liquid medicine.

Further, in one example, continuing to refer to fig. 1, the first anti-reflux device 2A is disposed downstream of the communication of the integrated passage 15 with the bypass pipe 14 in the flow direction of the liquid medicine.

The first anti-backflow device 2A is arranged at the downstream of the communication position of the integrated channel 15 and the bypass port 13 or the bypass pipe 14 along the flow direction of the liquid medicine, so that the pressure of the liquid medicine from the liquid conveying pipe and the bypass port 13 or the bypass pipe 14 is concentrated at the upstream of the first anti-backflow device 2A, and the anti-backflow capacity of the anti-backflow extension pipe 1 is improved.

It should be understood that the arrangement of the first anti-backflow device 2A and the second anti-backflow device 2B is not limited to the above example, which is only a preferred embodiment of the present invention, and it is also possible to only retain the first anti-backflow device 2A.

Further, as shown in fig. 3, the first anti-backflow device 2A and the second anti-backflow device 2B include a main body 20, the main body 20 is integrally cylindrical, one end of the main body 20 is provided with a liquid inlet 21, and the other end is provided with a liquid outlet 23; the cross-sectional area of the liquid inlet 21 is smaller than that of the liquid outlet 23; the liquid inlet 21 is communicated with the flow limiting hole 22 and the liquid outlet 23 in sequence. The anti-backflow device is cylindrical as a whole, is matched with the inner wall of the extension pipe more tightly, has better sealing effect and avoids the liquid leakage and seepage phenomena; the cross-sectional area of the liquid inlet 21 is smaller than that of the liquid outlet 23, so that the liquid medicine pressure at the liquid inlet 21 is higher, and the anti-backflow effect is improved.

In a specific example, as shown in fig. 3, the first anti-backflow device 2A and the second anti-backflow device 2B further include flow-limiting members, a first connection portion 25 is disposed at a lower portion of the liquid inlet 21, a second connection portion 26 is disposed at a lower portion of the flow-limiting hole 22, and the flow-limiting members are fixedly connected to the first connection portion 25 and the second connection portion 26 respectively; and a flow restricting cavity 24, the flow restricting cavity 24 being disposed between the liquid inlet 21 and the flow restricting orifice 22. The current-limiting piece can seal inlet 21 and restricted aperture 22, and restricted flow chamber 24 can keep in addition and flow back the partial liquid medicine that flows back so far, and the pressure of the partial liquid medicine that flows back of release, and then the tendency of flowing back of alleviating the liquid medicine helps promoting anti-reflux effect.

First anti-reflux device 2A and second in this application are resisted and are flowed device 2B and utilize the cooperation each other of current-limiting piece and restriction chamber 24 to make the fluid forward flow through anti-reflux device very easy, it is difficult to flow to return, it is the cooperation each other of current-limiting piece and restriction chamber 24 that is the most important in the anti-reflux device, so their positional relationship and structure are extremely important to anti-reflux effect, for make between current-limiting piece and the restriction chamber 24 positional relationship can not flow along with the fluid and the live time is longer for taking place the deformation and then influence anti-reflux effect, this application sets up the position of connecting portion with the current-limiting piece and fixes.

As a preferred embodiment under the present example, with continued reference to fig. 3, the flow restriction member includes a first flow restriction pair including a first anti-backflow sheet 201 and a second anti-backflow sheet 202, and a second flow restriction pair, the first connection portion 25 includes two oppositely disposed grooves, at least a portion of each of the first anti-backflow sheet 201 and the second anti-backflow sheet 202 is disposed in the two grooves, respectively; the second flow restriction pair comprises a third anti-backflow sheet 203 and a fourth anti-backflow sheet 204, the second connecting part 26 comprises two oppositely arranged grooves, and at least one part of each of the third anti-backflow sheet 203 and the fourth anti-backflow sheet 204 is respectively arranged in the two grooves; the first anti-backflow tab 201 is shorter than the second anti-backflow tab 202, and the third anti-backflow tab 203 is shorter than the fourth anti-backflow tab 204. The inner wall structure and the groove of the main body 20 are utilized, so that the anti-backflow sheet is fixed in the groove, the matching structure of the anti-backflow sheet and the groove is simple, the connection is reliable, and the assembly efficiency is improved. In addition, because the lengths of the two anti-backflow pieces in each flow limiting pair are different, the anti-backflow pieces are easier to overlap together to seal the flow limiting hole 22 and/or the liquid inlet 21 when the liquid medicine flows back.

It should be understood that the material and structure of the flow restriction member are not limited in the present invention, and as a preferred embodiment of the present invention, the first anti-backflow piece 201, the second anti-backflow piece 202, the third anti-backflow piece 203, and the fourth anti-backflow piece 204 are made of rubber material, but other materials and structures shown in fig. 4 may be used.

It should also be understood that the present invention is not limited to the connection manner and the specific structure of the current-limiting member and the first connection portion 25 and the second connection portion 26, and the current-limiting member may be fastened, bonded, or screwed.

As a preferred embodiment of the present invention, as shown in fig. 3, a guide slope 27 is provided between the restriction hole 22 and the liquid outlet 23. When the liquid medicine flows backwards due to the arrangement of the guide inclined plane 27, the pressure of the liquid medicine acts on the fixed connection part of the anti-backflow sheet and the connecting part at first, so that the two anti-backflow sheets of the second flow limiting pair can be overlapped and sealed with the flow limiting hole 22 more easily, and the anti-backflow effect is improved.

As a preferred embodiment of the present invention, as shown in fig. 3, a first position-limiting portion 28 is disposed at the upper portion of the liquid inlet 21, and a second position-limiting portion 29 is disposed at the lower portion of the liquid outlet 23. The arrangement of the first limiting part 28 and the second limiting part 29 prevents the anti-reflux device from displacing in the extension pipe and affecting the anti-reflux effect.

In one specific example, with continued reference to fig. 3, both the upper portion of the inlet port 21 and the lower portion of the outlet port 23 are provided with limit bosses. The limiting boss is simple in structure and simple to process.

The structure of the first stopper 28 and the second stopper 29 according to the present invention is not particularly limited, and other structures such as a stopper rib may be used.

As shown in fig. 5 and 6, an infusion apparatus comprises a venous infusion tube 3, an infusion needle and the anti-reflux extension tube 1 disclosed in the foregoing, wherein a fluid inlet 11 is communicated with one end of the venous infusion tube 3 close to the infusion needle, a fluid outlet 12 is communicated with the infusion needle, and a bypass port 13 is communicated with an external liquid medicine source.

It should be understood that the connection mode and connection structure of the fluid inlet 11 and the intravenous infusion tube 3, the fluid outlet 12 and the infusion needle, and the bypass port 13 and the external drug liquid source are not particularly limited, and the following embodiments can be adopted:

example 1: as shown in fig. 5 and 6, the fluid inlet 11 and the intravenous line 3, the fluid outlet 12 and the infusion needle, and the bypass port 13 and the external drug liquid source are connected by the connector 5.

The infusion device is connected through the connector 5, so that the structure is simple and reliable, and the assembly and disassembly are convenient, thereby being beneficial to improving the infusion efficiency. Of course, it can also adopt the connection mode of snap connection, screw connection, etc.

Further, as shown in fig. 5 and 6, the infusion needle includes an infusion needle connection tube 41 and an infusion needle head 42; the diameter of the anti-reflux extension tube 1 is 1.5-3 times of the diameter of the transfusion needle connecting tube 41, and the diameter of the anti-reflux extension tube 1 is 0.8-1 time of the diameter of the intravenous transfusion tube 3.

Through a plurality of tests of the inventor, the relationship between the diameter of the anti-backflow extension pipe 1, the diameter of the intravenous infusion tube 3 and the diameter of the infusion needle connecting pipe 41 enables the fluid resistance in the extension pipe to be small, the fluid flow in the infusion tube cannot be influenced, the anti-backflow effect can be achieved, and the stable and safe operation of the infusion process can be guaranteed.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims (7)

1. An anti-backflow extension pipe, characterized in that the anti-backflow extension pipe comprises a fluid inlet, a fluid outlet and a bypass port which are communicated with the fluid inlet;

an integration channel in communication with the fluid outlet; the fluid inlet and the bypass port can be respectively communicated with the integrated channel, and liquid medicine can enter the integrated channel through the fluid inlet and the bypass port and is discharged through the fluid outlet;

the integrated channel is characterized by also comprising an anti-backflow device, wherein the anti-backflow device comprises a first anti-backflow device, and the first anti-backflow device is arranged in the integrated channel;

the first anti-backflow device comprises a main body, the main body is integrally cylindrical, one end of the main body is provided with a liquid inlet, and the other end of the main body is provided with a liquid outlet; the cross-sectional area of the liquid inlet is smaller than that of the liquid outlet; the liquid inlet is communicated with the flow limiting hole and the liquid outlet in sequence;

the first anti-backflow device further comprises a flow limiting piece, a first connecting part is arranged at the lower part of the liquid inlet, a second connecting part is arranged at the lower part of the flow limiting hole, and the flow limiting piece is fixedly connected with the first connecting part and the second connecting part respectively; the flow limiting cavity is arranged between the liquid inlet and the flow limiting hole;

the flow limiting piece comprises a first flow limiting pair and a second flow limiting pair, the first flow limiting pair comprises a first anti-backflow sheet and a second anti-backflow sheet, the first connecting part comprises two oppositely arranged grooves, and at least one part of each of the first anti-backflow sheet and the second anti-backflow sheet is arranged in the two grooves respectively; the second flow limiting pair comprises a third anti-backflow sheet and a fourth anti-backflow sheet, the second connecting part comprises two oppositely arranged grooves, and at least one part of each of the third anti-backflow sheet and the fourth anti-backflow sheet is arranged in the two grooves respectively; the first anti-backflow piece is shorter than the second anti-backflow piece, and the third anti-backflow piece is shorter than the fourth anti-backflow piece.

2. The anti-backflow extension pipe as claimed in claim 1, further comprising a bypass pipe, one end of the bypass pipe being communicated with the integration channel, and the other end of the bypass pipe being provided with the bypass port;

the anti-backflow device further comprises a second anti-backflow device, and the second anti-backflow device is arranged in the bypass pipe.

3. The extension tube of claim 2, wherein the first anti-backflow device is disposed downstream of the connection between the integrated channel and the bypass port in the flow direction of the liquid medicine;

or, the first anti-backflow device is arranged at the downstream of the communication position of the integrated channel and the bypass pipe along the flow direction of the liquid medicine.

4. The anti-backflow extension tube as claimed in claim 3, wherein a guide slope is provided between the flow restriction hole and the liquid outlet.

5. The anti-backflow extension pipe as claimed in claim 4, wherein a first limiting portion is disposed at an upper portion of the liquid inlet, and a second limiting portion is disposed at a lower portion of the liquid outlet.

6. An infusion apparatus, comprising a venous infusion tube and an infusion needle, characterized in that, the infusion apparatus further comprises the anti-reflux extension tube of any one of claims 1 to 5, the fluid inlet is communicated with one end of the venous infusion tube close to the infusion needle, the fluid outlet is communicated with the infusion needle, and the bypass port is communicated with an external liquid medicine source.

7. The infusion set according to claim 6, wherein the infusion needle comprises an infusion needle connection tube and an infusion needle head;

the diameter of the anti-backflow extension pipe is 1.5-3 times of that of the infusion needle connecting pipe, and the diameter of the anti-backflow extension pipe is 0.8-1 times of that of the venous infusion tube.

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