Pneumatic return valve and gluing equipment

Abstract

The utility model relates to the technical field of gluing equipment, and discloses a pneumatic return valve and gluing equipment, the pneumatic return valve comprises a valve body, an ejector pin and a piston, the valve body is provided with an air inlet connector, a liquid inlet, a return hole and a valve port, the ejector pin and the piston are arranged in the valve body, and the ejector pin is used for blocking the valve port. When the first acting force of fluid on the ejector pin through the liquid inlet and the valve port is larger than the second acting force of gas entering through the gas inlet connector of the valve body on the piston, the liquid can push the ejector pin to open the valve port, liquid backflow is achieved, and constant-pressure conveying of the liquid conveying system is facilitated. When the liquid pressure is weakened to make the first acting force smaller than the second acting force, the piston pushes the ejector pin to close the valve port under the second acting force, and therefore the backflow hole is blocked. Movement of the ejector pin and the piston is directly controlled by pressure changes of liquid and gas, adjustment through spring force is not needed, the adjusting mode is more direct and not affected by spring performance, the adjusting precision is easier to control, and stability and reliability are improved.

Description

Technical Field

[0001] The present application relates to the technical field of glue coating equipment, and in particular to a pneumatic reflux valve and glue coating equipment. Background Art

[0002] In the related art, a return valve is set in the glue delivery system of the glue coating equipment to prevent the system from being damaged due to excessive pressure. A return spring is usually set inside the return valve. By adjusting the relative position between the adjusting stud and the valve body, the tightness of the pressure spring is adjusted to achieve the adjustment of different opening and closing pressures to meet different usage requirements. This adjustment method is cumbersome to operate and it is difficult to control the adjustment accuracy. To solve this problem, in other technologies, the return valve is connected to the air source, and the air source pressure pushes the piston against the return spring to adjust the spring tightness. This solution has certain difficulties in practical application. On the one hand, since the elastic force of the spring changes with the compression amount, it is difficult to accurately change the opening pressure of the glue by changing the air source pressure. On the other hand, the use effect of this solution is affected by the performance of the spring. After long-term use, the loss of the spring will affect the accuracy of the opening and closing pressure of the return valve. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides a pneumatic reflux valve to improve the accuracy of the opening and closing pressure.

[0004] The utility model also provides a glue coating device with the pneumatic reflux valve.

[0005] The first embodiment of the utility model provides a pneumatic reflux valve, including a valve body, a ejector pin and a piston, wherein:

[0006] The valve body has an inner cavity, one end of the valve body is provided with a liquid inlet connected to the inner cavity, and the valve body is provided with a valve port at a position set distance from the liquid inlet in the inner cavity, and a reflux hole connected to the inner cavity is also provided on the side wall of the valve body, the reflux hole passes through the inner wall of the valve body corresponding to the position of the valve port away from the liquid inlet, and the other end of the valve body is provided with an air inlet interface connected to the inner cavity, and the air inlet interface is used to connect to an air source;

[0007] The ejector pin is arranged in the inner cavity, and one end of the ejector pin facing the liquid inlet can abut against and block the valve port. The ejector pin is sealed with the inner wall of the valve body at the side of the reflux hole away from the valve port. The side of the ejector pin facing the valve port defines a first pressure-bearing surface for bearing fluid pressure. The ejector pin can be driven to slide relative to the valve body in a direction close to or away from the valve port to close or open the valve port. A gap for fluid to flow through is provided between the peripheral wall of the ejector pin corresponding to the position of the reflux hole and the inner wall of the valve body.

[0008] The piston is disposed in the inner cavity and is located between the ejector pin and the air inlet interface. One end of the piston abuts against one end of the ejector pin away from the valve port. The side of the piston away from the ejector pin defines a second pressure-bearing surface for bearing gas pressure. The piston is sealingly connected to the inner wall of the valve body and can be driven to slide relative to the valve body in a direction close to or away from the valve port. Wherein, when the pressure applied to the first pressure-bearing surface is greater than the pressure applied to the second pressure-bearing surface, the ejector pin pushes the piston to move in a direction away from the valve port, so that the valve port is opened to communicate the liquid inlet and the return hole.

[0009] The pneumatic return valve according to the embodiment of the present invention has at least the following beneficial effects: During application, the gas entering through the air inlet interface has a second acting force on the second pressure-bearing surface of the piston, and the fluid has a first acting force on the first pressure-bearing surface of the ejector pin through the liquid inlet and the valve port. When the first acting force is greater than the second acting force, the liquid can push the ejector pin to move in a direction away from the valve port to open the valve port, so that the liquid inlet is communicated with the return hole to realize liquid return. When the liquid pressure weakens such that the first acting force is less than the second acting force, the piston pushes the ejector pin to move in the direction of the valve port to close the valve port, thereby blocking the return hole, which helps the liquid delivery system to maintain constant pressure delivery. The movement of the ejector pin and the piston is directly controlled by the pressure changes of the liquid and the gas, without the need to adjust through the spring force. By changing the air pressure of the gas introduced into the air inlet channel, the opening and closing pressure of the valve port can be directly adjusted. The adjustment method is more direct, not affected by the spring performance, and it is easier to control the adjustment accuracy, improving stability and reliability.

[0010] According to the pneumatic return valve of some embodiments of the present invention, the valve body includes a lower main body and an upper main body, wherein:

[0011] The inside of the lower main body is hollow to form a first cavity. The lower main body has opposite ends. The first cavity penetrates through the two ends of the lower main body and forms the liquid inlet at one end. A raised shoulder is provided on the inner wall of the lower main body corresponding to the proximal end of the liquid inlet to form the valve port. The return hole penetrates through the inner wall of the lower main body on the side of the valve port away from the liquid inlet.

[0012] The upper main body has opposite ends. The inside of the upper main body is hollow to form a second cavity, and the second cavity penetrates through the two ends of the upper main body. One end of the upper main body is sealingly connected to one end of the lower main body away from the liquid inlet.

[0013] The second cavity is communicated with the first cavity to form the inner cavity. The piston passes through the second cavity, and the ejector pin passes through the first cavity. The other end of the upper main body away from the lower main body is adapted to be connected to an air inlet joint for connecting to a gas source.

[0014] According to the pneumatic return valve of some embodiments of the present utility model, the thimble includes a first rod portion and a first sealing portion surrounding the outer peripheral wall of the first rod portion, wherein:

[0015] One end of the first rod portion is used to block the valve port, and one side surface of the first rod portion and the first sealing portion facing the valve port defines the first pressure-bearing surface;

[0016] The first sealing portion is connected to the first rod portion, and the first sealing portion is slidably disposed in the first cavity to drive the first rod portion to open or close the valve port, and the first sealing portion is in sealing contact with the inner wall of the lower body;

[0017] The return hole is located between the sealing portion and the valve port.

[0018] According to the pneumatic return valve of some embodiments of the present utility model, a first annular groove is provided on the outer wall of the first sealing portion, a first sealing ring is sleeved in the first annular groove, and the first sealing ring is pressed between the groove wall of the first annular groove and the inner wall of the lower body.

[0019] According to the pneumatic return valve of some embodiments of the present utility model, the piston includes a second rod portion and a second sealing portion surrounding the outer peripheral wall of the second rod portion, wherein:

[0020] One end of the second rod portion is used to abut against the thimble;

[0021] The second sealing portion is connected to the second rod portion, the second sealing portion is slidably disposed in the second cavity to drive the second rod portion to move in a direction close to or away from the valve port, the second sealing portion is in sealing connection with the inner wall of the upper body, and one side surface of the second sealing portion and the second rod portion facing away from the thimble defines the second pressure-bearing surface.

[0022] According to the pneumatic return valve of some embodiments of the present utility model, a second annular groove is provided on the outer wall of the second sealing portion, a second sealing ring is sleeved in the second annular groove, and the second sealing ring is pressed between the groove wall of the second annular groove and the inner wall of the upper body.

[0023] According to the pneumatic return valve of some embodiments of the present utility model, the valve body further includes an upper cover, the upper cover is sealingly connected to one end of the upper body facing away from the lower body, the inside of the upper cover is hollow to form the air inlet interface, and the air inlet interface is adapted to be connected to an air inlet joint for accessing a gas source.

[0024] According to the pneumatic return valve of some embodiments of the present utility model, the area of the second pressure-bearing surface is larger than the area of the first pressure-bearing surface.

[0025] According to the pneumatic reflux valve of some embodiments of the present utility model, a third annular groove is provided on the outer wall of the valve body corresponding to the proximal end of the liquid inlet, the third annular groove is located between the liquid inlet and the reflux hole, and a third sealing ring is provided in the third annular groove;

[0026] And / or, an annular boss and a clamping groove are provided on the outer wall of the valve body between the liquid inlet and the reflux hole, the clamping groove is located between the annular boss and the liquid inlet, a fourth sealing ring is sleeved on the outer wall of the valve body between the clamping groove and the annular boss, and a retaining ring is clamped in the clamping groove for limiting the fourth sealing ring.

[0027] The second aspect embodiment of the present utility model also provides a glue application device, which includes a branch seat and the pneumatic reflux valve of the first aspect embodiment above. A liquid channel, a valve body installation cavity and a reflux channel are provided inside the branch seat. The valve body installation cavity is communicated with the liquid channel, the reflux channel is communicated with the valve body installation cavity, one end of the valve body of the pneumatic reflux valve having the liquid inlet is hermetically connected to the inner wall of the valve body installation cavity, the liquid inlet is communicated with the liquid channel, and the reflux hole is communicated with the reflux channel. When the pressure of the liquid in the liquid channel applied to the first pressure-bearing surface is greater than the pressure of the gas entering from the air inlet interface applied to the second pressure-bearing surface, the liquid can push the thimble to move so as to open the valve port, and the liquid channel is communicated with the reflux channel through the opened valve port and the reflux hole.

[0028] The glue application device of the embodiment of the present utility model has at least the following beneficial effects: During application, the liquid channel can be used to connect the adhesive conveying channel of the glue application device, and the conveyed liquid can be the adhesive to be sprayed. When the first acting force of the liquid in the liquid channel of the branch seat on the thimble is greater than the second acting force of the gas pressure in the air inlet channel on the piston, the liquid can push the thimble to open the valve port to realize liquid reflux, which helps the adhesive conveying system to maintain a constant pressure. Moreover, for the glue application device of the present utility model, by changing the air pressure of the gas introduced into the air inlet channel, the opening and closing pressure of the valve port can be changed, so as to adapt to different use requirements. The adjustment method is flexible and convenient, easy to control the adjustment accuracy, improve the stability and reliability, thereby ensuring the stability of the output glue pressure and guaranteeing the spraying quality.

[0029] The additional aspects and advantages of the present utility model will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present utility model. Description of the Drawings

[0030] Figure 1 It is a cross-sectional view schematic diagram of the pneumatic reflux valve according to an embodiment of the present utility model;

[0031] Figure 2 Schematic diagram of the pneumatic return valve Figure 1 for disassembly;

[0032] Figure 3 Assembly diagram (sectional view) of the lower body and components such as the ejector pin in an embodiment;

[0033] Figure 4 Schematic diagram of the Figure 3 lower body in

[0034] Figure 5 Schematic diagram of the Figure 3 ejector pin in

[0035] Figure 6 Assembly diagram (sectional view) of the upper body, piston, upper cover, air inlet joint and other components in an embodiment;

[0036] Figure 7 Schematic diagram of the Figure 6 upper body in

[0037] Figure 8 Schematic diagram of the Figure 6 piston in

[0038] Figure 9 Partial structural schematic diagram of the glue application device according to an embodiment of the present utility model, wherein the valve port of the pneumatic return valve is in a closed state;

[0039] Figure 10 Partial structural schematic diagram of the glue application device according to an embodiment of the present utility model, wherein the valve port is open and the pneumatic return valve is in a constant pressure state;

[0040] Figure 11 Partial structural schematic diagram of the glue application device according to an embodiment of the present utility model, wherein the valve port is open and the pneumatic return valve is not in a constant pressure state.

[0041] Reference numerals:

[0042] Air inlet joint 100; air inlet passage 110; upper cover 120;

[0043] Upper body 200; second cavity 210; air inlet interface 220; limiting part 230; sealing structure 240; mounting hole 250; shaft seal 260; gasket 270; circlip 280; through hole 290;

[0044] Lower body 300; first cavity 310; gap 311; liquid inlet 320; valve port 330; return hole 340; shoulder 350; third annular groove 360; annular boss 370; clamping groove 380;

[0045] Ejector pin 400; First sealing part 410; First annular groove 411; First sealing ring 412; First rod part 420; End part 421; First pressure-bearing surface 430;

[0046] Piston 500; Second sealing part 510; Second annular groove 511; Second sealing ring 512; Second rod part 520; Second pressure-bearing surface 530;

[0047] Third sealing ring 600; Fourth sealing ring 700; Retaining ring 710;

[0048] Diverging seat 800; Liquid channel 810; Glue inlet 811; Valve body installation cavity 820; Return channel 830; Fifth sealing ring 840. Detailed implementation manners

[0049] The following will clearly and completely describe the concept and technical effects generated by the present utility model in combination with the embodiments, so as to fully understand the purpose, features and effects of the present utility model. Obviously, the described embodiments are only part of the embodiments of the present utility model, rather than all embodiments. Based on the embodiments of the present utility model, other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present utility model.

[0050] In the description of the embodiments of the present utility model, if it involves orientation description, such as "upper", "lower", "front", "rear", "left", "right", etc., the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present utility model.

[0051] In the description of the embodiments of the present utility model, if a certain feature is referred to as "set", "fixed", "connected", "installed" on another feature, it can be directly set, fixed, connected, installed on another feature, or indirectly set, fixed, connected, installed on another feature. In the description of the embodiments of the present utility model, if it involves "several", its meaning is more than one, if it involves "multiple", its meaning is more than two, if it involves "greater than", "less than", "exceeding", it should be understood as not including the number itself, if it involves "above", "below", "within", it should be understood as including the number itself. If it involves "first", "second", it should be understood as used to distinguish technical features, rather than indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0052] The embodiment of the utility model provides a pneumatic reflux valve and a gluing device having the pneumatic reflux valve, which can adjust the opening and closing pressure of the valve port by adjusting the intake air pressure, can achieve online adjustment, and the adjustment method is convenient and reliable, and the accuracy is easy to control. The embodiment of the utility model is introduced below in conjunction with the drawings of the specification:

[0053] refer to Figures 1 to 4 The pneumatic reflux valve of the first embodiment of the utility model comprises a valve body, a ejector pin 400 and a piston 500, wherein:

[0054] The valve body has an inner cavity, one end of the valve body is provided with a liquid inlet 320 connected to the inner cavity, and the valve body is provided with a valve port 330 at a position in the inner cavity at a set distance from the liquid inlet 320, and the side wall of the valve body is also provided with a reflux hole 340 connected to the inner cavity, and the reflux hole 340 passes through the inner wall of the valve body corresponding to the position of the valve port 330 away from the liquid inlet 320. The other end of the valve body is provided with an air inlet interface 220 connected to the inner cavity, and the air inlet interface 220 is used to connect to the air source.

[0055] The ejector pin 400 is disposed in the inner cavity. One end of the ejector pin 400 facing the liquid inlet 320 can abut against and block the valve port 330. The ejector pin 400 is sealed and connected to the inner wall of the valve body at the side of the reflux hole 340 away from the valve port 330. The ejector pin 400 defines a first pressure-bearing surface 430 for bearing fluid pressure on the side facing the valve port 330. The ejector pin 400 can be driven to slide relative to the valve body in a direction close to or away from the valve port 330 to close or open the valve port 330. A gap 311 for fluid to flow through is provided between the peripheral wall of the ejector pin 400 corresponding to the position of the reflux hole 340 and the inner wall of the valve body. When the valve port 330 is open, the liquid inlet 320 is connected to the reflux hole 340 through the gap 311, so that liquid (such as adhesive) can flow into the gap 311 through the liquid inlet 320 and flow out through the reflux hole 340.

[0056] The piston 500 is arranged in the inner cavity and is located between the ejector pin 400 and the air inlet interface 220. The piston 500 is sealed and connected to the inner wall of the valve body. One end of the piston 500 abuts against the end of the ejector pin 400 away from the valve port 330. The side of the piston 500 away from the ejector pin 400 defines a second pressure-bearing surface 530 for bearing gas pressure. The piston 500 can be driven to slide relative to the valve body in a direction close to or away from the valve port 330.

[0057] Among them, when the pressure applied to the first pressure-bearing surface 430 is greater than the pressure applied to the second pressure-bearing surface 530, the ejector pin 400 pushes the piston 500 to move in a direction away from the valve port 330, so that the valve port 330 is opened to connect the liquid inlet 320 and the return hole 340. In application, the gas entering through the air inlet interface 220 has a second acting force on the second pressure-bearing surface 530 of the piston 500, and the fluid has a first acting force on the first pressure-bearing surface 430 of the ejector pin 400 through the liquid inlet 320 and the valve port 330. When the first acting force is greater than the second acting force, the liquid can push the ejector pin 400 to move in a direction away from the valve port 330 to open the valve port 330, so that the liquid inlet 320 is connected to the return hole 340 to realize liquid reflux. When the liquid pressure weakens so that the first acting force is less than the second acting force, the piston 500 pushes the ejector pin 400 to move in the direction of the valve port 330 to close the valve port 330, thereby blocking the return hole 340, which helps the liquid delivery system to maintain constant-pressure delivery.

[0058] Therefore, the movement of the ejector pin 400 and the piston 500 is directly controlled by the pressure changes of the liquid and the gas, without the need for spring force adjustment. The spring is omitted. By changing the air pressure of the gas introduced into the air inlet passage 110, the opening and closing pressure of the valve port 330 can be directly adjusted. The adjustment method is more direct, not affected by the spring performance, and it is easier to control the adjustment accuracy, improving stability and reliability.

[0059] Reference Figures 9 to 11 , when used in the glue application equipment, the pneumatic reflux valve can be arranged in the adhesive delivery channel. The liquid inlet 320 is connected to the liquid channel 810, the return hole 340 is connected to the return channel 830, and the air inlet interface 220 is connected to the air source. The hydraulic set value for opening the valve port 330 for reflux can be determined by setting the air source pressure. During use, the air source pressure can be set so that the piston 500 receives a set second acting force. When the liquid pressure at the liquid inlet 320 is less than the set value, the first acting force received by the ejector pin 400 is less than the second acting force received by the piston 500. The piston 500 and the ejector pin 400 keep the valve port 330 closed under the action of the air pressure, and the liquid inlet 320 and the return hole 340 are isolated from each other. When the hydraulic pressure in the liquid channel 810 increases so that the liquid pressure at the liquid inlet 320 is greater than the set value, the first acting force acting on the ejector pin 400 is greater than the second acting force of the air pressure acting on the piston 500. Thus, the liquid pushes the ejector pin 400 and the piston 500 to move to open the valve port 330 (reference Figure 10 、 Figure 11), when the valve port 330 is opened, the reflux hole 340 is connected with the liquid inlet 320, and the liquid can enter the valve port 330 through the liquid inlet 320 and flow out from the reflux hole 340. The reflux hole 340 is used to connect to the reflux channel 830 to achieve reflux pressure relief of the liquid. When the hydraulic pressure in the liquid channel 810 decreases to less than the set value, the piston 500 pushes the ejector pin 400 back to close the valve port 330 under the second force (refer to Figure 9 ).

[0060] Therefore, the opening pressure of the valve port 330 is determined by the incoming air pressure. Changing the air pressure of the gas entering the air inlet interface 220 can change the hydraulic upper limit required to open the valve port 330 in the liquid channel 810, thereby adapting to different usage requirements. The adjustment method is flexible and convenient, and it is easy to control the adjustment accuracy.

[0061] refer to Figure 1 and Figure 2 In some embodiments, the pneumatic reflux valve further includes an air inlet connector 100, which can be sealed and connected to the end of the valve body away from the liquid inlet 320, and cover the air inlet interface 220, or the valve body further includes an upper cover 120, which is sealed and connected to the end of the valve body away from the liquid inlet 320, and the upper cover 120 is hollow inside to form the air inlet interface 220, and the air inlet interface 220 is suitable for connecting the air inlet connector 100 for accessing the gas source. The end of the upper cover 120 facing the piston 500 can be used to abut the piston 500. Among them, the air inlet connector 100 is hollow inside to form an air inlet channel 110, and the air inlet channel 110 is connected to the inner cavity. The air inlet channel 110 is used to access the gas source, such as passing high-pressure gas of a set pressure, so as to apply a force to the second pressure-bearing surface 530 of the piston 500.

[0062] It is understandable that the gas pressure acts on the second pressure-bearing surface 530 of the piston 500, so the second force can be obtained by multiplying the gas pressure and the area of the second pressure-bearing surface 530. The liquid acts on the first pressure-bearing surface 430 through the valve port 330, so the first force can be obtained by multiplying the hydraulic pressure and the area of the cross section of the valve port 330. In some embodiments, the area of the second pressure-bearing surface 530 is larger than the area of the cross section of the valve port 330, so that the gas has a larger effective area relative to the liquid. Since the pressure acting on the surface is the product of the pressure and the effective area (F=pS), the requirements for the air pressure strength can be reduced under the set opening pressure of the valve port 330. Similarly, a larger effective area is also more conducive to expanding the adjustable range of the opening pressure of the valve port 330 by adjusting the air pressure, and optimizing the applicability of the pneumatic reflux valve.

[0063] It can be understood that various control requirements can be met by reasonably configuring the area ratio / difference between the cross-section of the second pressure-bearing surface 530 and the valve port 330, which is beneficial to the optimal design of the pneumatic return valve. When the required pressure is the same, increasing the effective area can reduce the required pressure, and, when the provided pressure remains unchanged, the provided force can be increased.

[0064] refer to Figures 2 to 5 In some embodiments, the valve body includes a lower body 300 and an upper body 200, which are sealed and connected to form a split valve body, which can facilitate processing and assembly of internal structural parts. Figure 3 and Figure 4 The interior of the lower body 300 is hollow to form a first cavity 310. The lower body 300 has two opposite ends. The first cavity 310 runs through the two ends of the lower body 300, and forms a liquid inlet 320 at one end, and is connected to the upper body 200 at the other end.

[0065] The ejector pin 400 is inserted into the first cavity 310 , and a raised shoulder 350 is provided on the inner wall of the lower body 300 corresponding to the proximal end of the liquid inlet 320 to form a valve port 330 . The reflux hole 340 passes through the valve port 330 of the lower body 300 and the inner wall on the side away from the liquid inlet 320 .

[0066] refer to Figure 3 and Figure 4 The upper body 200 has two opposite ends, and one end of the upper body 200 is sealed and connected to the lower body 300. The interior of the upper body 200 is hollow to form a second cavity 210, and the second cavity 210 passes through both ends of the upper body 200. The piston 500 is arranged in the second cavity 210. The second cavity 210 is connected to the first cavity 310 at one end of the upper body 200 connected to the lower body 300. The second cavity 210 and the first cavity 310 together constitute the inner cavity of the valve body. The other end of the upper body 200 away from the lower body 300 is suitable for connecting to the air inlet connector 100 for accessing the air source. For example, the second cavity 210 passes through the other end of the upper body 200 to form an air inlet interface 220, and the air inlet interface 220 is suitable for connecting to the air inlet connector 100, so as to allow air to enter the second cavity 210; or, the second cavity 210 passes through the other end of the upper body 200 to form a connecting hole, and the connecting hole is suitable for connecting to the upper cover 120 provided with the air inlet interface 220, and the air inlet interface 220 is used to connect to the air inlet connector 100.

[0067] refer to Figure 1 and Figure 2, the sealing connection method between the upper main body 200 and the lower main body 300 can be: an installation hole 250 is provided at one end of the upper main body 200 facing away from the air inlet interface 220, and the lower main body 300 is connected to the upper main body 200 within the installation hole 250 at one end facing away from the liquid inlet 320, and a sealing structure 240 (such as a sealing ring) is provided between the outer wall of the lower main body 300 and the inner wall of the installation hole 250; or, an installation hole 250 is provided at one end of the lower main body 300 facing away from the liquid inlet 320, and the upper main body 200 is connected to the lower main body 300 within the installation hole 250 at one end facing away from the air inlet interface 220, and a sealing structure 240 (such as a sealing ring) is provided between the outer wall of the upper main body 200 and the inner wall of the installation hole 250.

[0068] Reference Figures 3 to 5 , in the pneumatic return valve of some embodiments, the ejector pin 400 includes a first rod portion 420 and a first sealing portion 410 surrounding the outer peripheral wall of the first rod portion 420. One end of the first rod portion 420 is used to block the valve port 330, and a gap 311 for liquid to flow through is formed between the first rod portion 420 and the inner wall of the first cavity 310. The side surfaces of the first rod portion 420 and the first sealing portion 410 facing the valve port 330 define a first pressure-bearing surface 430. The first sealing portion 410 is connected to the first rod portion 420, and the first sealing portion 410 is slidably disposed within the first cavity 310 to drive the first rod portion 420 to open or close the valve port 330. The first sealing portion 410 is in sealing contact with the inner wall of the lower main body 300 (i.e., the inner wall of the first cavity 310). The return hole 340 is located between the sealing portion and the valve port 330, so as to achieve sealing on the side of the return hole 340 facing away from the valve port 330, ensuring that the liquid flows out through the return hole 340 after the valve port 330 is opened, and preventing the liquid from entering the side of the first sealing portion 410 facing away from the valve port 330 and affecting the stability of the hydraulic pressure.

[0069] Among them, the end portion 421 of the first rod portion 420 for blocking the valve port 330 can be a cylindrical structure or a conical structure. The first sealing portion 410 has an outer cylindrical surface coaxial with the end portion 421 of the first rod portion 420. The first cavity 310 is a cylindrical cavity, and the valve port 330 is a circular hole structure coaxial with the first cavity 310. Thus, the ejector pin 400 is slidably disposed within the first cavity 310 through the first sealing portion 410, which can make the first sealing portion 410, the end portion 421 of the first rod portion 420 facing the valve port 330, and the valve port 330 coaxial, helping to ensure the effectiveness of the closure of the valve port 330. The first sealing portion 410 is used to guide the first rod portion 420, effectively avoiding the problem that the valve port 330 is not tightly closed due to the deviation of the end portion 421 of the first rod portion 420.

[0070] Among them, the outer wall of the first sealing portion 410 may be provided with a first annular groove 411. A first sealing ring 412 is sleeved in the first annular groove 411. The bottom wall of the first annular groove 411 is coaxial with the end portion 421 of the first rod portion 420. Thus, the outer wall of the first sealing ring 412 is coaxial with the end portion 421 of the first rod portion 420. Therefore, after the first sealing portion 410 with the first sealing ring 412 is disposed in the first inner cavity, the end portion 421 of the first rod portion 420 is coaxial with the valve port 330, and during the process of the first sealing portion 410 sliding along the inner wall of the first cavity 310, the first rod portion 420 remains coaxial with the valve port 330, effectively preventing the end portion 421 of the first rod portion 420 from deflecting. The first sealing ring 412 is pressed between the groove wall of the first annular groove 411 and the inner wall of the lower main body 300, realizing the sealed connection between the first sealing portion 410 and the inner wall of the first cavity 310, and being able to effectively block the liquid entering from the liquid inlet 320 on the side of the return hole 340 facing away from the liquid inlet 320.

[0071] The first sealing ring 412 may be an O-ring, forming a line seal, which can reduce the flatness requirement of the sealing surface and improve the effectiveness of the seal. The number of the first annular grooves 411 may be one or at least two. The at least two first annular grooves 411 may be arranged at intervals along the axial direction of the first sealing portion 410. Each first annular groove 411 may be respectively provided with a first sealing ring 412. Thus, at least two first sealing rings 412 may be provided on the first sealing portion 410, thereby improving the reliability of the seal and the stability of the movement of the first sealing portion 410.

[0072] Reference Figures 6 to 8 , in the pneumatic return valve of some embodiments, the piston 500 includes a second rod portion 520 and a second sealing portion 510 surrounding the outer peripheral wall of the second rod portion 520. One end of the second rod portion 520 is used to abut against the thimble 400. The second sealing portion 510 is connected to the second rod portion 520. The second sealing portion 510 is slidably disposed in the second cavity 210 to drive the second rod portion 520 to move in a direction close to or away from the valve port 330. The second sealing portion 510 is sealingly connected to the inner wall of the upper main body 200 (i.e., the inner wall of the second cavity 210). Thus, the gas entering the second cavity 210 from the air inlet interface 220 can be sealed. The surface of the second sealing portion 510 and the second rod portion 520 on the side facing away from the thimble 400 defines a second pressure-bearing surface 530, effectively ensuring that the air acts on the second pressure-bearing surface 530 and preventing leakage to the side of the second sealing portion 510 facing away from the air inlet interface 220 and affecting the pressure stability. The second sealing ring 512 may be an O-ring, forming a line seal, which can reduce the flatness requirement of the sealing surface and improve the effectiveness of the seal. Or a star-shaped ring may also be selected to form a lip seal. The star-shaped ring can generate a seal through the interference deformation of the lip, and has a small contact area, which can reduce the friction force with the inner wall of the second cavity 210.

[0073] Among them, an outer wall of the second sealing portion 510 is provided with a second annular groove 511, a second sealing ring 512 is sleeved in the second annular groove 511, and the second sealing ring 512 is pressed between a groove wall of the second annular groove 511 and an inner wall of the upper main body 200. To achieve a sealed connection between the second sealing portion 510 and the inner wall of the second cavity 210, and can effectively block the entering gas on a side of the second sealing portion 510 facing the air inlet interface 220. The second rod portion 520 can pass through one end of the upper main body 200 facing the lower main body 300 and extend into the first cavity 310 to abut against the thimble 400. Among them, a through hole 290 is formed at one end of the second cavity 210 facing the lower main body 300, and the second rod portion 520 passes through the through hole 290.

[0074] Reference Figures 6 to 8 , in some embodiments, an installation hole 250 is provided at one end of the upper main body 200 facing away from the air inlet interface 220. The lower main body 300 is connected to the upper main body 200 within the installation hole 250 at one end facing away from the liquid inlet 320. The through hole 290 of the second cavity 210 communicates with the installation hole 250 and is aligned with the thimble 400, so that the second rod portion 520 passes through the through hole 290 and the installation hole 250 and extends into the first cavity 310 to abut against the thimble 400. Among them, a shaft seal 260 is sleeved on a portion of the second rod portion 520 located within the installation hole 250. An installation platform for axially abutting against a side of the shaft seal 260 facing away from the lower main body 300 is provided within the installation hole 250, and a gasket 270 groove and a snap ring 710 groove are provided on a side of the shaft seal 260 facing away from the installation platform. A gasket 270 is provided within the gasket 270 groove, a snap ring 280 is installed within the snap ring 710 groove, the gasket 270 abuts against a side of the shaft seal 260 facing away from the installation platform, and the snap ring 280 abuts against the gasket 270, thereby restricting the axial position of the shaft seal 260. When the second sealing portion 510 drives the second rod portion 520 to move relative to the upper main body 200, the sealant remains in contact with an outer peripheral wall of the second rod portion 520, so that a seal between the second rod portion 520 and the installation hole 250 can be achieved on a side of the through hole 290 facing the lower main body 300, and the movement of the second rod portion 520 can be guided, effectively preventing the second rod portion 520 from deflecting.

[0075] Reference Figures 1 to 4 , in the pneumatic reflux valve of the above embodiment, an outer wall of the valve body corresponding to a proximal end of the liquid inlet 320 may further be provided with a third annular groove 360 and / or a fourth annular groove for playing a certain sealing role when the lower main body 300 is connected to an installation structure (such as a manifold 800).

[0076] In some embodiments, the third annular groove 360 is located between the liquid inlet 320 and the reflux hole 340, and a third sealing ring 600 is provided in the third annular groove 360. The third sealing ring 600 may be selected as an O-ring to form a line seal.

[0077] The valve body (e.g., the lower body 300) may also be provided with an annular boss 370 and a slot 380 on the outer wall corresponding to the liquid inlet 320 and the reflux hole 340. The slot 380 is located between the annular boss 370 and the liquid inlet 320. The valve body is provided with a fourth sealing ring 700 on the outer wall between the slot 380 and the annular boss 370. A retaining ring 710 is clamped in the slot 380. The retaining ring 710 is located on the side of the fourth sealing ring 700 away from the reflux hole 340, and is used to limit the fourth sealing ring 700. The fourth sealing ring 700 and the third sealing ring 600 may be closer to the liquid inlet 320 relative to the third sealing ring 600.

[0078] In some embodiments, only one of the third sealing ring 600 and the fourth sealing ring may be provided, which can also play a certain sealing role when connected with the branch seat 800.

[0079] refer to Figure 1 , Figures 9 to 10 , and in combination with the foregoing, the glue coating equipment provided by the second embodiment of the utility model includes a branch seat 800 and the pneumatic reflux valve of the first embodiment, and also includes a glue gun for spraying glue. The branch seat 800 is used for diversion and filtering in the glue delivery system. The branch seat 800 is provided with a liquid channel 810, a valve body installation cavity 820 and a reflux channel 830. One end of the liquid channel 810 passes through the branch seat 800 to form a glue inlet 811 for passing the glue. The valve body is connected to the valve body installation cavity 820 and can be connected by threads. For example, the outer wall of the lower body 300 is provided with an external thread, and the valve body installation cavity 820 is provided with an internal thread suitable for being screwed with the external thread, thereby realizing the threaded connection between the two. A third sealing ring 600 and / or a fourth sealing ring 700 are also provided between the lower body 300 and the valve body installation cavity 820 to achieve the sealing of the valve body installation cavity 820. A fifth sealing ring 840 is further provided between the port position of the valve body installation cavity 820 and the lower body 300 .

[0080] During the spraying process, the high-pressure fluid pumped by the pump enters the liquid channel 810 through the glue inlet 811, and then enters the branch seat 800 for transportation. The valve body installation cavity 820 is connected to the liquid channel 810, and the reflux channel 830 is connected to the valve body installation cavity 820. The valve body of the pneumatic reflux valve has an end of the liquid inlet 320 that is sealed and connected to the inner wall of the valve body installation cavity 820. The liquid inlet 320 is connected to the liquid channel 810, and the reflux hole 340 is connected to the reflux channel 830. When the liquid pressure does not reach the reflux valve opening pressure, the first force applied by the liquid in the liquid channel 810 to the first pressure-bearing surface 430 is not greater than the second force applied by the gas entering from the air inlet interface 220 to the second pressure-bearing surface 530. Under the action of the second force, the piston 500 remains abutting against the ejector pin 400 to close the valve port 330 (refer to Figure 9 ), the liquid is transported through the liquid channel 810.

[0081] When the first acting force exerted by the liquid in the liquid passage 810 on the first pressure-bearing surface 430 is greater than the second acting force exerted by the gas entering from the air inlet interface 220 on the second pressure-bearing surface 530, the liquid in the liquid passage 810 can push the ejector pin 400 to move so as to open the valve port 330, and the liquid passage 810 is communicated with the return passage 830 through the opened valve port 330 and the return hole 340. Thus, after the fluid enters the manifold 800, it first passes through the pneumatic return valve, part of the liquid enters the valve body, and then part of the fluid is returned to the melting cylinder through the return passage 830, and part continues to be conveyed to the glue gun for glue application work. The return of the liquid can prevent the system from being damaged due to excessive pressure, and at the same time helps the adhesive conveying system to maintain a constant pressure and reach a constant pressure state under the action of air pressure (refer to Figure 10 ), so as to ensure the stability of the output glue pressure and guarantee the spraying quality. After turning off the air source connected to the air inlet interface 220, at this time, the liquid pushes the ejector pin 400 to drive the piston 500 to move upward until it abuts against the upper cover 120 of the valve body, and the pneumatic return valve does not perform constant pressure regulation, and all the liquid returns through the return valve (refer to Figure 11 ).

[0082] Moreover, as can be seen from the above, for the glue application device of the present invention, by changing the air pressure of the gas introduced into the air inlet passage 110, the upper limit of the hydraulic pressure required to open the valve port 330 in the liquid passage 810 can be changed, so as to adapt to different usage requirements. The pneumatic return valve omits the setting of a spring, and the adjustment of the opening pressure is not affected by the performance of the spring. The adjustment method is more reliable and stable, and it is easy to control the adjustment accuracy, so as to ensure the stability and accuracy of the glue pressure in the glue cavity and guarantee the spraying quality.

[0083] The glue application device of the embodiment of the present invention can be used for polyamine hot melt adhesives and can be applied to the glue spraying of various products, such as for the adhesion of carton handles, the adhesion of paper boxes, paper cups, sanitary products and straws, etc. By configuring a PLC controller, the pressure of the air inlet interface 220 can be adjusted online to meet different opening and closing pressure requirements.

[0084] The above has described the embodiments of the present application in detail with reference to the accompanying drawings. However, the present application is not limited to the above embodiments. Within the knowledge scope of those of ordinary skill in the art to which the present application pertains, various changes can be made without departing from the purpose of the present application. In addition, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

Claims

1. Pneumatic reflux valve, characterized in that, include: A valve body having an inner cavity, one end of the valve body being provided with a liquid inlet connected to the inner cavity, and the valve body being provided with a valve port at a position in the inner cavity at a set distance from the liquid inlet, a reflux hole connected to the inner cavity being further provided on the side wall of the valve body, the reflux hole penetrating the inner wall of the valve body corresponding to a position of the valve port away from the liquid inlet, and an air inlet interface connected to the inner cavity being provided at the other end of the valve body, the air inlet interface being used to connect to an air source; an ejector pin disposed in the inner cavity, wherein one end of the ejector pin facing the liquid inlet can abut against and block the valve port, the ejector pin is sealedly connected to the inner wall of the valve body at a side of the reflux hole away from the valve port, the ejector pin can be driven to slide relative to the valve body in a direction close to or away from the valve port to close or open the valve port, the side of the ejector pin facing the valve port defines a first pressure-bearing surface for bearing fluid pressure, and a gap for fluid to flow through is provided between the peripheral wall of the ejector pin corresponding to the position of the reflux hole and the inner wall of the valve body; A piston is disposed in the inner cavity and located between the ejector pin and the air inlet port, one end of the piston abuts against one end of the ejector pin away from the valve port, a side of the piston away from the ejector pin defines a second pressure-bearing surface for bearing gas pressure, the piston is sealingly connected to the inner wall of the valve body, and the piston is driven to slide relative to the valve body in a direction close to or away from the valve port; When the pressure applied to the first pressure-bearing surface is greater than the pressure applied to the second pressure-bearing surface, the ejector pin pushes the piston to move in a direction away from the valve port, so that the valve port is opened to connect the liquid inlet and the reflux hole.

2. The pneumatic return valve according to claim 1, wherein The valve body comprises a lower body and an upper body, wherein: The lower body is hollow inside to form a first cavity, the lower body has two opposite ends, the first cavity runs through the two ends of the lower body, and forms the liquid inlet at one end, the inner wall of the lower body is provided with a raised shoulder corresponding to the proximal end of the liquid inlet to form the valve port, and the reflux hole runs through the inner wall of the valve port of the lower body away from the liquid inlet; The upper body has two opposite ends, the interior of the upper body is hollow to form a second cavity, and the second cavity passes through the two ends of the upper body, and one end of the upper body is sealed and connected to one end of the lower body away from the liquid inlet; The second cavity is connected to the first cavity to form the inner cavity, the piston is inserted into the second cavity, the ejector pin is inserted into the first cavity, and the other end of the upper body away from the lower body is suitable for connecting to an air inlet connector for accessing an air source.

3. The pneumatic return valve according to claim 2, characterized in that, The ejector pin comprises a first rod portion and a first sealing portion surrounding an outer peripheral wall of the first rod portion, wherein: One end of the first rod portion is used to block the valve port, and the first rod portion and the first sealing portion define the first pressure-bearing surface on one side facing the valve port; The first sealing portion is connected to the first rod portion, the first sealing portion is slidably disposed in the first cavity to drive the first rod portion to open or close the valve port, and the first sealing portion is in sealing contact with the inner wall of the lower body; The return hole is located between the sealing portion and the valve port.

4. The pneumatic reflux valve according to claim 3, characterized in that, The outer wall of the first sealing portion is provided with a first annular groove, a first sealing ring is sleeved in the first annular groove, and the first sealing ring is pressed tightly between the groove wall of the first annular groove and the inner wall of the lower body.

5. The pneumatic return valve according to claim 2, characterized in that, The piston comprises a second rod portion and a second sealing portion surrounding an outer peripheral wall of the second rod portion, wherein: One end of the second rod portion is used to abut against the ejector pin; The second sealing portion is connected to the second rod portion, and the second sealing portion is slidably disposed in the second cavity to drive the second rod portion to move toward or away from the valve port. The second sealing portion is sealingly connected to the inner wall of the upper body, and the second sealing portion and the second rod portion define the second pressure-bearing surface on a side surface facing away from the ejector pin.

6. The pneumatic reflux valve according to claim 5, wherein, The outer wall of the second sealing portion is provided with a second annular groove, a second sealing ring is sleeved in the second annular groove, and the second sealing ring is pressed between the groove wall of the second annular groove and the inner wall of the upper body.

7. The pneumatic reflux valve according to claim 2, characterized in that, The valve body further comprises an upper cover, which is sealed to an end of the upper body facing away from the lower body, and the interior of the upper cover is hollow to form the air inlet interface, which is suitable for connecting to an air inlet connector for accessing an air source.

8. The pneumatic reflux valve according to claim 1, characterized in that, The area of the second pressure-bearing surface is larger than the area of the cross section of the valve port.

9. The pneumatic return valve according to any one of claims 1 to 8, characterized in that, The outer wall of the valve body corresponding to the proximal end of the liquid inlet is provided with a third annular groove, the third annular groove is located between the liquid inlet and the reflux hole, and a third sealing ring is provided in the third annular groove; And / or, the valve body is provided with an annular boss and a groove on the outer wall corresponding to the liquid inlet and the reflux hole, the groove is located between the annular boss and the liquid inlet, the valve body is provided with a fourth sealing ring on the outer wall between the groove and the annular boss, and a retaining ring is clamped in the groove for limiting the fourth sealing ring.

10. A glue - applying device, characterized in that, include: A branch seat and a pneumatic return valve as claimed in any one of claims 1 to 9, wherein: The branch seat is provided with a liquid channel, a valve body installation cavity and a reflux channel inside, the valve body installation cavity is connected to the liquid channel, and the reflux channel is connected to the valve body installation cavity; The valve body of the pneumatic reflux valve has one end of the liquid inlet sealedly connected to the inner wall of the valve body mounting cavity, the liquid inlet is connected to the liquid channel, and the reflux hole is connected to the reflux channel. When the pressure applied by the liquid in the liquid channel to the first pressure-bearing surface is greater than the pressure applied by the gas entering from the air inlet interface to the second pressure-bearing surface, the liquid can push the ejector pin to move and thus open the valve port, and the liquid channel is connected to the reflux channel through the opened valve port and the reflux hole.

Images