Tubular membrane welding rod device

Abstract

The utility model discloses a tubular membrane welding rod device which comprises an outer rod, a middle rod and an inner rod, a non-woven fabric layer is welded and wound outside the outer rod; the middle rod comprises a middle rod body, a first coating head and a second coating head, the outer diameter of the first coating head is larger than that of the second coating head, the middle rod body is sleeved with the outer rod, and a first material liquid runner is formed between the inner wall of the outer rod and the outer wall of the middle rod body; the inner rod is sleeved with the middle rod, a second feed liquid flow channel is defined by the inner wall of the inner rod and the outer wall of the inner rod, a second feed liquid outlet of the second feed liquid flow channel is formed between the first coating head and the second coating head, and a core liquid flow channel used for core liquid flowing is formed in the inner rod; the first coating head is used for extruding first feed liquid output from the first feed liquid outlet to the inner layer of the non-woven fabric layer to form a first film layer, and the second coating head is used for extruding second feed liquid output from the second feed liquid outlet to the inner wall of the first film layer to form a second film layer. Through the arrangement, the bonding strength between the film layer and the non-woven fabric layer can be improved, and the uniformity of the thickness of the film layer is improved.

Description

Technical Field

[0001] This utility model relates to the field of tubular membrane preparation technology, and in particular to a tubular membrane welding rod device. Background Technology

[0002] Organic tubular membranes have wide flow channels, are less prone to concentration polarization, and are easy to clean and maintain. The pretreatment requirements for feed water are relatively simple, requiring only the removal of hard particles that could directly damage the membrane by passing the water through a grid and basket filter. In addition, the membrane material itself has characteristics such as high strength, antifouling, and high pressure resistance. Therefore, they are widely used in the separation of high-concentration industrial wastewater such as landfill leachate, pharmaceutical wastewater, alkali recovery, oily wastewater, electronic wastewater, and coking wastewater, as well as materials such as food, fermentation broth, and tea beverages.

[0003] Currently, organic tubular membranes are prepared using tubular membrane welding and coating equipment. Non-woven fabric strips are welded into non-woven tubes using ultrasonic waves, and then coated with a casting solution. The non-woven fabric serves as a support layer, providing mechanical support for the membrane separation layer, which in turn acts as a filter. Existing non-woven fabric support layers are generally single-layer or double-layer structures, resulting in problems such as low bonding strength between the membrane separation layer and the non-woven fabric layer, and uneven thickness of the membrane separation layer. Chinese patent CN218131074U discloses a welding rod device and a tubular membrane. By setting different feed solutions for the membrane base layer and the separation layer, the bonding strength between the membrane layer and the non-woven fabric is improved. However, this pre-phase-inversion membrane requires a pre-evaporation time of more than 10 seconds before immersion in the coagulation bath to complete the phase inversion membrane formation process. Excessive pre-evaporation time leads to the formation of finger-like pores or cavitation pores in the produced membrane tube, resulting in low pressure resistance and a tendency for fouling.

[0004] Therefore, how to provide a tubular membrane welding rod device to at least partially solve the above-mentioned problems is a technical problem that needs to be solved by those skilled in the art. Utility Model Content

[0005] The purpose of this invention is to provide a tubular membrane welding rod device that can improve the bonding strength between the membrane layer and the nonwoven fabric layer and improve the uniformity of the membrane thickness.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A tubular membrane welding rod device, comprising:

[0008] The outer rod has an outer layer for welding and wrapping a non-woven fabric layer.

[0009] The middle rod includes a middle rod body, a first coating head and a second coating head connected in sequence, and the outer diameter of the first coating head is larger than the outer diameter of the second coating head. The middle rod body is sleeved inside the outer rod, and a liquid flow channel is formed between the inner wall of the outer rod and the outer wall of the middle rod body. The liquid flow channel includes a liquid inlet and a liquid outlet.

[0010] The inner rod is sleeved inside the middle rod, and a liquid flow channel is formed between the inner wall of the middle rod and the outer wall of the inner rod. The liquid flow channel includes two liquid inlets and two liquid outlets. The liquid outlets are located between the first coating head and the second coating head. A core liquid flow channel is opened inside the inner rod, which includes a core liquid inlet and a core liquid outlet.

[0011] The first coating head is used to squeeze the first liquid output from the liquid outlet to the inner layer of the nonwoven fabric layer to form a first film layer, and the second coating head is used to squeeze the second liquid output from the liquid outlet to the inner wall of the first film layer to form a second film layer.

[0012] Preferably, 2-4 support bars are provided between the middle rod body and the outer rod, and the support bars limit the middle rod body to make it concentric with the outer rod.

[0013] Preferably, the outer diameter of the first coating head is larger than the outer diameter of the middle rod body, and the outer diameter of the first coating head is smaller than the outer diameter of the outer rod.

[0014] Preferably, the first coating head and the second coating head are provided with a groove with an annular structure in the middle, and a thickness control ring is installed in the groove to control the thickness of the first film layer and the second film layer.

[0015] Preferably, the thickness control ring is made of an elastic material.

[0016] Preferably, the depth of the card slot is 0.5-1mm and the width of the card slot is 1-2mm;

[0017] The outer diameter of the thickness control ring on the first coating head is 0.3-0.6 mm smaller than the diameter of the outer rod, and the outer diameter of the thickness control ring on the second coating head is 0.1-0.3 mm smaller than the outer diameter of the thickness control ring on the first coating head.

[0018] Preferably, the inner rod, middle rod, first coating head, and second coating head are arranged coaxially.

[0019] Preferably, the inner rod, middle rod, and outer rod are all equal-diameter circular tubes, and the first coating head and the second coating head are both variable-diameter circular tubes.

[0020] Preferably, the connection between the middle rod and the first coating head, and the connection between the second coating head and the first coating head, is welding.

[0021] Preferably, both the first and second feed inlets have flared structures.

[0022] Compared to the aforementioned background technology, the present invention provides a tubular membrane welding rod device, comprising: an outer rod, a middle rod, and an inner rod; the outer layer of the outer rod is used for welding and winding a non-woven fabric layer; the middle rod includes a middle rod body, a first coating head, and a second coating head connected in sequence, wherein the outer diameter of the first coating head is larger than the outer diameter of the second coating head, the middle rod body is sleeved inside the outer rod, and a liquid flow channel is formed between the inner wall of the outer rod and the outer wall of the middle rod body, the liquid flow channel including a liquid inlet and a liquid outlet; the inner rod is sleeved on the middle rod. Inside, a liquid flow channel is formed between the inner wall of the middle rod and the outer wall of the inner rod. The liquid flow channel includes a liquid inlet and a liquid outlet. The liquid outlet is located between the first coating head and the second coating head. A core liquid flow channel is opened inside the inner rod. The core liquid flow channel includes a core liquid inlet and a core liquid outlet. The first coating head is used to squeeze the liquid output from the liquid outlet to the inner layer of the nonwoven fabric layer to form a first film layer. The second coating head is used to squeeze the liquid output from the liquid outlet to the inner wall of the first film layer to form a second film layer.

[0023] Specifically, in the fabrication of the tubular membrane, a non-woven fabric layer is first welded and wrapped around the outer wall of the outer rod. Then, liquid liquid one is injected into the liquid liquid one channel through the liquid liquid one inlet. Liquid liquid one flows out from the liquid liquid one outlet and forms a first film layer on the inner wall of the non-woven fabric layer under the action of the first coating head. At the same time, liquid liquid two is injected into the liquid liquid two channel through the liquid liquid two inlet. Liquid liquid two flows out from the liquid liquid two outlet and forms a second film layer on the inner wall of the first film layer under the action of the second coating head. It should be noted that a special core liquid is always circulated in the inner rod, which effectively controls heat transfer during the welding process and prevents... The tubular membrane is damaged due to overheating; on the other hand, it is discharged from the core liquid outlet into the second membrane layer and reacts chemically with it, so that the coated first and second membrane layers undergo liquid-liquid phase separation, forming a porous membrane separation layer. This avoids uneven thickness caused by the flow of the liquid and reduces the residence time of the liquid layer in the air, which is beneficial for controlling the temperature and humidity of the air section. Finally, the structure of two coating heads allows for two-stage extrusion coating of the liquid, which can effectively avoid the problem of uneven membrane layer caused by single coating, and at the same time, it can make the liquid better bond with the nonwoven fabric layer. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the tubular membrane welding rod device provided in an embodiment of the present invention;

[0026] Figure 2 for Figure 1 Cross-sectional view of the AA structure.

[0027] in:

[0028] 100 - Outer rod;

[0029] 210 - Middle rod body, 220 - First coating head, 230 - Second coating head;

[0030] 300 - Inner rod, 310 - Core fluid flow channel, 320 - Core fluid inlet, 330 - Core fluid outlet;

[0031] 400-the first channel of material liquid, 410-the first inlet of material liquid, 420-the first outlet of material liquid;

[0032] 500-the second flow channel of material and liquid, 510-the second inlet of material and liquid, 520-the second outlet of material and liquid;

[0033] 600-Support bar;

[0034] 700 - Card slot, 710 - Thickness control ring. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0036] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] In the description of this utility model, it should be understood that the terms "upper", "lower", "inner", "outer", "top" and "bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the position or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations of this utility model.

[0038] The purpose of this invention is to provide a tubular membrane welding rod device that can improve the bonding strength between the membrane layer and the nonwoven fabric layer and improve the uniformity of the membrane thickness.

[0039] To achieve the above objectives, the present invention provides the following technical solution:

[0040] Please see Figure 1 and Figure 2 This embodiment provides a tubular membrane welding rod device, including: an outer rod 100, a middle rod, and an inner rod 300; the outer layer of the outer rod 100 is used for welding and winding a non-woven fabric layer; the middle rod includes a middle rod body 210, a first coating head 220, and a second coating head 230 connected in sequence, and the outer diameter of the first coating head 220 is larger than the outer diameter of the second coating head 230; the middle rod body 210 is sleeved inside the outer rod 100, and a liquid flow channel 400 is formed between the inner wall of the outer rod 100 and the outer wall of the middle rod body 210, the liquid flow channel 400 including a liquid inlet 410 and a liquid outlet 420; the inner rod 300 is sleeved inside the middle rod, and the middle rod body 300 is used for welding and winding a non-woven fabric layer; the outer layer of the outer rod 1 ... A liquid flow channel 500 is formed between the inner wall of the rod and the outer wall of the inner rod 300. The liquid flow channel 500 includes a liquid inlet 510 and a liquid outlet 520. The liquid outlet 520 is located between the first coating head 220 and the second coating head 230. A core liquid flow channel 310 is provided inside the inner rod 300. The core liquid flow channel 310 includes a core liquid inlet 320 and a core liquid inlet 330. The first coating head 220 is used to squeeze the liquid output from the liquid outlet 420 to the inner layer of the nonwoven fabric layer to form a first film layer. The second coating head 230 is used to squeeze the liquid output from the liquid outlet 520 to the inner wall of the first film layer to form a second film layer.

[0041] Specifically, such as Figure 1 As shown, the outer rod 100, middle rod, and inner rod 300 are all hollow tubular structures. The outer rod 100 is welded and wrapped with a non-woven fabric layer, the thickness of which is set according to the specific requirements. The middle rod consists of a middle rod body 210, a first coating head 220, and a second coating head 230. The middle rod body 210 is fitted inside the outer rod 100 with a gap between them, which is the first material flow channel 400. The first coating head 220 and the second coating head 230 are located below the outer rod 100 and the middle rod. Finally, the inner rod 300 runs through the entire middle rod from top to bottom. There is also a gap between the inner rod 300 and the middle rod, which is the second material flow channel 500. The channel inside the inner rod 300 is the core liquid flow channel 310. In this embodiment, the first and second materials are the casting liquids required for manufacturing tubular membranes, while the core liquid is a specially formulated liquid to control the temperature of the first and second materials during flow.

[0042] It should be noted that the first liquid flow channel 400, the second liquid flow channel 500, and the core liquid flow channel 310 are all equipped with inlets, and all are located in... Figure 1The top of the welding rod device has three inlets: a first liquid inlet 410, a second liquid inlet 510, and a core liquid inlet 320. The first liquid outlet 420 is located at the lower end of the outer rod 100. After flowing out of this outlet, the first liquid passes over the surface of the first coating head 220 and is squeezed against the inner wall of the nonwoven fabric layer to form a first film layer. The second liquid outlet 520 is located at the connection between the first coating head 220 and the second coating head 230 and extends radially. This arrangement is to allow the second liquid to be squeezed against the inner wall of the first film layer by the second coating head 230 after flowing out, thus forming a second film layer. In this way, tubular membranes can be manufactured using the welding rod device.

[0043] Furthermore, the core liquid inlet 330 is located at the lower end of the inner rod 300, meaning that the core liquid flowing into the core liquid channel 310 will flow out from the lower end of the welding rod device and into the tubular membrane formed by the first membrane layer and the second membrane layer. The core liquid can chemically react with the first and second liquids to promote the phase transformation of the first and second liquids.

[0044] In general, during the fabrication of the tubular membrane, the nonwoven fabric layer is first welded and wound onto the outer wall of the outer rod 100. Then, liquid one is injected into the liquid one flow channel 400 through the liquid one inlet 410. Liquid one flows out from the liquid one outlet 420 and forms a first membrane layer on the inner wall of the nonwoven fabric layer under the action of the first coating head 220. Simultaneously, liquid two is injected into the liquid two flow channel 500 through the liquid two inlet 510. Liquid two flows out from the liquid two outlet 520 and forms a second membrane layer on the inner wall of the first membrane layer under the action of the second coating head 230. It should be noted that a special core liquid is always introduced into the inner rod 300, which effectively... The process controls heat transfer during welding to prevent damage to the tubular membrane due to overheating. On the other hand, the liquid is discharged from the core liquid inlet 330 into the second membrane layer, where it undergoes a chemical reaction to induce a phase transformation between the coated first and second membrane layers, creating a porous membrane separation layer. This avoids uneven thickness caused by the flow of the liquid and reduces the residence time of the liquid layer in the air, which is beneficial for controlling the temperature and humidity of the air section. Finally, the structure with two coating heads allows for two-stage extrusion coating of the liquid, effectively avoiding the unevenness of the membrane layer caused by a single coating, and enabling the liquid to better bond firmly to the nonwoven fabric layer.

[0045] Preferably, 2-4 support bars 600 are provided between the middle rod body 210 and the outer rod 100. The support bars 600 limit the middle rod body 210 so that it is concentric with the outer rod 100.

[0046] like Figure 2As shown, in this embodiment, the middle rod body 210 and the outer rod 100 are preferably connected by four support bars 600, and the four support bars 600 are of equal length and evenly distributed so that the middle rod body 210 and the outer rod 100 are concentric; the gap between two adjacent support bars 600 is the liquid outlet 420; with this arrangement, it can be ensured that the liquid can be evenly distributed on the circumference of the first coating head 220 when it flows out, so that the first membrane layer of the manufactured tubular membrane is evenly distributed.

[0047] Of course, the number of support bars 600 can be adjusted according to actual needs, and this article does not make a specific limit.

[0048] Preferably, the outer diameter of the first coating head 220 is larger than the outer diameter of the middle rod body 210, and the outer diameter of the first coating head 220 is smaller than the outer diameter of the outer rod 100.

[0049] Understandably, in order to ensure that the first coating head 220 can squeeze the liquid material into the nonwoven fabric layer to form the first film layer, in this embodiment, the outer diameter of the first coating head 220 is set to be larger than the outer diameter of the middle rod body 210. At the same time, in order to ensure smooth manufacturing of the tubular film, the outer diameter of the first coating head 220 needs to be set smaller than the outer diameter of the outer rod 100. In this way, when the nonwoven fabric is welded and wound on the circumference of the outer rod 100, there will be a gap between it and the first coating head 220 for coating the liquid material, and the smooth sliding of the first coating head 220 can also be ensured.

[0050] Preferably, the first coating head 220 and the second coating head 230 are provided with a groove 700 with an annular structure in the middle, and a thickness control ring 710 is installed in the groove 700 to control the thickness of the first film layer and the second film layer.

[0051] Understandably, in order to further control the thickness of the first and second membrane layers in the tubular membrane, in this embodiment, a thickness control ring 710 is fitted at the middle of the first coating head 220 and the second coating head 230, i.e., at the point of maximum outer diameter; specifically, as shown... Figure 1 As shown, a ring-shaped groove 700 is provided in the middle of the first coating head 220 and the second coating head 230, and the thickness control ring 710 is installed in the groove 700.

[0052] When the thickness of the thickness control ring 710 is changed, the gap between it and the nonwoven fabric layer is changed, thereby changing the thickness of the membrane layer. Specifically, the thicker the thickness control ring 710, the thinner the first and second membrane layers will be, and the thinner the tubular membrane as a whole will be.

[0053] With this configuration, membrane tubes of different thicknesses can be produced by simply replacing the thickness control ring 710 without changing the welding rod device, thus improving the versatility of this embodiment.

[0054] Preferably, the thickness control ring 710 is made of an elastic material.

[0055] Understandably, in order to facilitate the fitting of the thickness control ring 710, in this embodiment, the thickness control ring 710 is specifically made of an elastic material, specifically, the material can be one or a mixture of several of silicone rubber, fluororubber, fluorosilicone rubber, and neoprene rubber.

[0056] Preferably, the depth of the slot 700 is 0.5-1mm and the width of the slot 700 is 1-2mm; the outer diameter of the thickness control ring 710 on the first coating head 220 is 0.3-0.6mm smaller than the diameter of the outer rod 100, and the outer diameter of the thickness control ring 710 on the second coating head 230 is 0.1-0.3mm smaller than the outer diameter of the thickness control ring 710 on the first coating head 220.

[0057] In this embodiment, the depth of the slot 700 is preferably between 0.5-1mm, and the width is preferably between 1-2mm. The specific dimensions can be adjusted according to actual conditions, and are not specifically limited herein. It is understood that since the first coating head 220 needs to coat the first film layer on the non-woven fabric layer, and the second coating head 230 coats the second film layer within the first film layer, it is necessary to ensure that the outer diameter of the first coating head 220 is larger than that of the second coating head 230. In this embodiment, the outer diameter of the thickness control ring 710 on the first coating head 220 is 0.3-0.6mm smaller than the diameter of the outer rod 100, while the outer diameter of the thickness control ring 710 on the second coating head 230 is 0.1-0.3mm smaller than that of the thickness control ring 710 on the first coating head 220.

[0058] Preferably, the inner rod 300, the middle rod, the first coating head 220, and the second coating head 230 are arranged coaxially.

[0059] Understandably, this arrangement can maximize the uniformity of the tubular film thickness produced by the welding rod device provided in this embodiment. Since the outer rod 100, inner rod 300, middle rod, first coating head 220 and second coating head 230 are coaxially arranged, the gap between the nonwoven fabric layer and the first coating head 220 is the same, which ensures the uniformity of the thickness of the first film layer. Similarly, the coaxial arrangement of the second coating head 230 and the first coating head 220 can also ensure the uniformity of the thickness of the second film layer.

[0060] Preferably, the inner rod 300, the middle rod and the outer rod 100 are all equal-diameter round tubes, and the first coating head 220 and the second coating head 230 are both variable-diameter round tubes.

[0061] like Figure 1 As shown, in this embodiment, the inner rod 300, the middle rod, and the outer rod 100 are all equal-diameter circular tubes. The flow channel formed by the three is mainly used to transport the liquid material. Since the first coating head 220 and the second coating head 230 need to squeeze the liquid material to form a film, the first coating head 220 and the second coating head 230 are both set as variable-diameter circular tubes with thinner ends and thicker middle. The thinner ends facilitate the flow of liquid material to prevent defects in the film layer during the coating process.

[0062] Preferably, the connection between the middle rod and the first coating head 220, the second coating head 230 and the first coating head 220 is a welding connection.

[0063] In this embodiment, the inner rod 300, middle rod, outer rod 100, first coating head 220 and second coating head 230 are preferably made of one or more of tungsten steel, high-speed steel and stainless steel. These materials have high hardness and corrosion resistance, which can extend the service life of the welding rod device.

[0064] Preferably, both the first inlet 410 and the second inlet 510 are flared structures.

[0065] like Figure 1 As shown in this embodiment, in order to facilitate the filling of liquid one and liquid two, both the liquid one inlet 410 and the liquid two inlet 510 are set as annular flared structures, and in order to facilitate their connection with the liquid filling device, their inner walls are also provided with threads.

[0066] Of course, the shapes of the first liquid inlet 410 and the second liquid inlet 510 can be adjusted according to actual needs, and this article does not make specific limitations.

[0067] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0068] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0069] The embodiments provided by this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this utility model. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of this utility model.

Claims

1. A tubular membrane welding wand apparatus, characterized by, The utility model relates to a kind of coating device, including: Outer rod, outer layer is used to weld winding non-woven fabric layer; Middle rod, including sequentially connected middle rod body, first coating head and second coating head, and the outer diameter of the first coating head is greater than the outer diameter of the second coating head, the middle rod body is sleeved in the outer rod, and the inner wall of the outer rod and the outer wall of the middle rod body form a first flow channel of liquid material, and the first flow channel of liquid material includes first liquid inlet and first liquid outlet; Inner rod, sleeved in the middle rod, and the inner wall of the middle rod and the outer wall of the inner rod form a second flow channel of liquid material, and the second flow channel of liquid material includes second liquid inlet and second liquid outlet, and the second liquid outlet is arranged between the first coating head and the second coating head, and the inner rod is provided with a core liquid flow channel, and the core liquid flow channel includes core liquid inlet and core liquid outlet; The first coating head is used to extrude the first liquid material output by the first liquid outlet to the inner layer of the non-woven fabric layer to form a first film layer, and the second coating head is used to extrude the second liquid material output by the second liquid outlet to the inner wall of the first film layer to form a second film layer.

2. The tube membrane welding wand apparatus of claim 1, wherein, 2-4 support bars are arranged between the middle rod body and the outer rod, the support bars limit the middle rod body to be concentric with the outer rod.

3. The tube membrane welding wand apparatus of claim 1, wherein, The outer diameter of the first coating head is greater than the outer diameter of the middle rod body, and the outer diameter of the first coating head is less than the outer diameter of the outer rod.

4. The tube membrane welding wand apparatus of claim 1, wherein, The first coating head and the second coating head are provided with a clamping groove in the middle in the form of a ring structure, and a thickness control ring is installed in the clamping groove to control the thickness of the first film layer and the second film layer.

5. The tube membrane welding wand apparatus of claim 4, wherein, The material of the thickness control ring is specifically an elastic material.

6. The tube membrane welding wand apparatus of claim 5, wherein, The depth of the clamping groove is 0.5-1mm, and the width of the clamping groove is 1-2mm. The outer diameter of the thickness control ring on the first coating head is 0.3-0.6mm less than the diameter of the outer rod, and the outer diameter of the thickness control ring on the second coating head is 0.1-0.3mm less than the outer diameter of the thickness control ring on the first coating head.

7. The tube membrane welding wand apparatus of claim 2, wherein, The inner rod, the middle rod, the first coating head and the second coating head are coaxially arranged.

8. The tube membrane welding wand apparatus of claim 7, wherein, The inner rod, the middle rod and the outer rod are all equal-diameter circular tubes, and the first coating head and the second coating head are variable-diameter circular tubes.

9. The tube membrane welding wand apparatus of claim 1, wherein, The middle rod and the first coating head, the second coating head and the first coating head are connected by welding.

10. The tube membrane welding wand apparatus of claim 1, wherein, The first liquid inlet and the second liquid inlet are both flared structures.

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