Pressure conversion device, glue solution conveying system and gluing equipment

Abstract

The utility model relates to the technical field of gluing equipment, and discloses a pressure conversion device, a glue solution conveying system and gluing equipment.The pressure conversion device comprises a first pressure regulating valve, a second pressure regulating valve, a pneumatic return valve and a switching valve, the pneumatic return valve comprises an air inlet connector, a liquid inlet and a return hole, and the liquid inlet is communicated with a liquid channel of the glue solution conveying system; the reflowing hole is communicated with a reflowing channel for reflowing the glue solution; the switching valve is connected to the first pressure regulating valve, the second pressure regulating valve and the pneumatic return valve; the switching valve is used for switching the air inlet interface to be communicated with the output end of the first pressure regulating valve or the output end of the second pressure regulating valve; during application, the first pressure regulating valve can be used for high-pressure regulation, and the second pressure regulating valve can be used for low-pressure regulation. Through switching of the switching valve, the pneumatic return valve can be quickly switched to be communicated with the first pressure regulating valve or the second pressure regulating valve, so that quick switching between high-pressure regulation and low-pressure regulation is realized, the valve opening pressure of the pneumatic return valve is conveniently and quickly switched, and the switching efficiency is improved.

Description

Technical Field

[0001] This application relates to the technical field of gluing equipment, and in particular to a pressure conversion device, a glue liquid conveying system and a gluing equipment. Background Art

[0002] In the related art, the gluing equipment sprays glue by conveying glue liquid to a glue gun through a glue liquid conveying system. An air-operated reflux valve is arranged in the glue liquid conveying system. The air-operated reflux valve connects an air source and a liquid conveying channel. At a set air pressure, when the pressure of the pumped glue liquid exceeds the set value, the hydraulic pressure drives the air-operated reflux valve to open, realizing partial reflux to prevent the system from being affected by too high hydraulic pressure and even causing system damage to the gluing quality. The opening pressure is controlled by changing the air pressure introduced into the air-operated reflux valve, but the conversion of the air pressure is rather troublesome and the switching efficiency is low. Content of the Utility Model

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. For this purpose, the utility model provides a pressure conversion device capable of improving the air pressure switching efficiency.

[0004] The utility model also provides a glue liquid conveying system and a gluing equipment having the pressure conversion device.

[0005] In the first aspect of the embodiments of the utility model, a pressure conversion device is provided, which is applicable to the glue liquid conveying system of a gluing equipment, and includes a first pressure regulating valve, a second pressure regulating valve, an air-operated reflux valve and a switching valve, wherein:

[0006] The first pressure regulating valve is adapted to connect to an air source and is used for regulating the output air pressure within a first air pressure range;

[0007] The second pressure regulating valve is adapted to connect to an air source and is used for regulating the output air pressure within a second air pressure range. The second pressure regulating valve is independent of the first pressure regulating valve, and the second air pressure range is smaller than the first air pressure range;

[0008] The air-operated reflux valve includes an air inlet interface, a liquid inlet and a reflux hole. The liquid inlet is adapted to communicate with the liquid channel of the glue liquid conveying system, and the reflux hole is adapted to communicate with a reflux channel for glue liquid reflux;

[0009] The switching valve is connected to the output end of the first pressure regulating valve, the output end of the second pressure regulating valve, and the air inlet interface of the pneumatic reflux valve. The switching valve is used to switch the air inlet interface to communicate with the output end of the first pressure regulating valve or the output end of the second pressure regulating valve. Wherein, the pneumatic reflux valve is configured such that when the air inlet interface is in a state of communicating with the output end of the first pressure regulating valve, the hydraulic pressure at the liquid inlet is greater than a first set value, the liquid inlet and the reflux hole are conducted; when the air inlet interface is in a state of communicating with the output end of the second pressure regulating valve, the hydraulic pressure at the liquid inlet is greater than a second set value, the liquid inlet and the reflux hole are conducted; and the first set value is greater than the second set value.

[0010] The pressure conversion device according to an embodiment of the present invention has at least the following beneficial effects: During application, the first pressure regulating valve adjusts the output air pressure within a first air pressure range, and the second pressure regulating valve is used to adjust the output air pressure within a second air pressure range. The second air pressure range is smaller than the first air pressure range. Thus, the first pressure regulating valve can perform high-pressure regulation relative to the second pressure regulating valve, and the second pressure regulating valve can perform low-pressure regulation relative to the first pressure regulating valve. By switching the switching valve, the pneumatic reflux valve can be quickly switched to communicate with the first pressure regulating valve or the second pressure regulating valve, thereby realizing the quick switching between high-pressure regulation and low-pressure regulation, and thus facilitating the quick switching of the opening pressure of the pneumatic reflux valve and improving the switching efficiency.

[0011] According to the pressure conversion device of some embodiments of the present invention, an exhaust valve is further connected between the second pressure regulating valve and the switching valve.

[0012] According to the pressure conversion device of some embodiments of the present invention, it further includes at least one of a first measuring device, a second measuring device, and a third measuring device; wherein,

[0013] The first measuring device is connected to the first pressure regulating valve and is used to measure the output air pressure of the first pressure regulating valve;

[0014] The second measuring device is connected to the second pressure regulating valve and is used to measure the output air pressure of the second pressure regulating valve;

[0015] The third measuring device is connected between the air inlet interface and the air outlet end of the switching valve and is used to measure the air pressure input into the air inlet interface of the pneumatic reflux valve.

[0016] According to the pressure conversion device of some embodiments of the present invention, the pneumatic reflux valve includes a valve body, a piston, and a thimble, wherein:

[0017] The valve body has an inner cavity. One end of the valve body is provided with the liquid inlet communicating with the inner cavity, and a valve port is arranged in the inner cavity of the valve body at a set distance from the liquid inlet. A return hole communicating with the inner cavity is also arranged on the side wall of the valve body, and the return hole penetrates through the inner wall of the valve body corresponding to the position on the side of the valve port away from the liquid inlet. The other end of the valve body is provided with the air inlet interface communicating with the inner cavity;

[0018] The thimble is arranged in the inner cavity. One end of the thimble facing the liquid inlet can abut against and block the valve port. The thimble is hermetically connected to the inner wall of the valve body on the side of the return hole away from the valve port. The thimble 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 first pressure-bearing surface for bearing fluid pressure is defined on the side of the thimble facing the valve port. A gap through which fluid can flow is formed between the peripheral wall of the thimble corresponding to the position of the return hole and the inner wall of the valve body;

[0019] The piston is arranged in the inner cavity and is located between the thimble and the air inlet interface. One end of the piston abuts against the end of the thimble away from the valve port. A second pressure-bearing surface for bearing gas pressure is defined on the side of the piston away from the thimble. The piston is hermetically connected to the inner wall of the valve body. The piston can be driven to slide relative to the valve body in a direction close to or away from the valve port;

[0020] Wherein, when the pressure applied to the first pressure-bearing surface is greater than the pressure applied to the second pressure-bearing surface, the thimble 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.

[0021] According to the pressure conversion device of some embodiments of the present invention, the valve body includes a lower main body and an upper main body, wherein:

[0022] 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 near 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;

[0023] 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 hermetically connected to the end of the lower main body away from the liquid inlet;

[0024] 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.

[0025] According to the pressure conversion device of some embodiments of the utility model, the switching valve is a two-position three-way solenoid valve, having a first air inlet end, a second air inlet end and an air outlet end, the first air inlet end is connected to the output end of the first pressure regulating valve through a first pipeline, the second air inlet end is connected to the output end of the second pressure regulating valve through a second pipeline, and the air outlet end is connected to the air inlet interface; the switching valve is used to switch the air outlet end to be connected with the first air inlet end or the second air inlet end, so as to switch the air outlet end to be connected with the first pressure regulating valve or the second pressure regulating valve.

[0026] The second aspect of the present invention also provides a glue delivery system, which is used in a glue coating device to deliver glue to a glue gun. The glue delivery system includes a branch seat, a delivery pump, and a pressure conversion device according to any one of the first aspects, wherein:

[0027] A liquid channel and a reflux channel are provided inside the branch seat, wherein the liquid channel is used to connect the glue container and the glue gun, and the reflux channel is suitable for connecting the glue container;

[0028] The delivery pump is connected to the liquid channel, and the delivery pump is suitable for delivering the glue in the glue container to the glue gun through the liquid channel;

[0029] A pressure conversion device, wherein the liquid inlet of the pneumatic reflux valve is connected to the liquid channel, and the reflux hole is connected to the reflux channel.

[0030] The glue delivery system of the embodiment of the utility model has at least the following beneficial effects: when used, the valve opening pressure of the pneumatic reflux valve can be quickly switched by the pressure conversion device, so that the liquid channel can transport liquid under high pressure or low pressure. After switching from high pressure to low pressure, the second pressure regulating valve is connected to the air inlet interface of the pneumatic reflux valve. Under the action of the pressure difference, the pneumatic reflux valve opens to form a larger channel, and most of the liquid in the liquid channel flows back from the reflux channel, so that the hydraulic pressure drops to the second set value, and the liquid channel maintains a low pressure state. When switching from low pressure to high pressure again, the first pressure regulating valve is connected to the air inlet interface of the pneumatic reflux valve, and the opened channel of the pneumatic reflux valve is reduced or closed, a small part of the liquid flows back or does not flow back, and the hydraulic pressure rises to the first set value. The hydraulic pressure in the liquid channel maintains a high pressure state for transportation. Therefore, the pressure switching is convenient and fast.

[0031] In a third aspect of the embodiments of the present utility model, a glue application device is further provided, which includes a glue gun and the glue liquid delivery system of the second aspect of the embodiments. The glue gun includes a glue spraying valve, and the glue spraying valve communicates with the liquid passage for spraying glue.

[0032] The glue application device of the embodiments of the present utility model has at least the following beneficial effects: During application, the switching of the liquid delivery pressure is facilitated through the glue liquid delivery system, enabling the glue gun to switch between the high-pressure spraying state or the low-pressure spraying state, or to switch to the low-pressure state during shutdown. Thus, when switching back to the high-pressure state, the pressure boost speed can be increased, and a large amount of glue spraying during startup can be avoided, thereby enhancing the applicability of the glue application device.

[0033] According to some embodiments of the present utility model, the glue application device further includes an air inlet pipeline and a solenoid valve. The air inlet pipeline is adapted to connect to an air source, the glue spraying valve communicates with the solenoid valve, and the solenoid valve communicates with the air inlet pipeline.

[0034] According to some embodiments of the present utility model, the glue application device further includes an air source filter. The first pressure regulating valve and the second pressure regulating valve are respectively connected to the air inlet pipeline, and the air source filter is connected to the air inlet pipeline for filtering the gas passing through the air inlet pipeline at the front ends of the first pressure regulating valve, the second pressure regulating valve, and the solenoid valve.

[0035] Additional aspects and advantages of the present utility model will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present utility model. Description of the Drawings

[0036] Figure 1 Schematic diagram of a pressure conversion device according to an embodiment of the present utility model;

[0037] Figure 2 Cross-sectional view of a pneumatic return valve in the pressure conversion device of the embodiments of the present utility model;

[0038] Figure 3 For Figure 2 Exploded view of the shown pneumatic return valve;

[0039] Figure 4 Assembly diagram (cross-sectional view) of the lower main body and the thimble and other components in the pneumatic return valve of an embodiment;

[0040] Figure 5 Assembly diagram (cross-sectional view) of the upper main body and the piston, the upper cover, the air inlet joint and other components in an embodiment;

[0041] Figure 6 Partial structural diagram of a glue application device according to an embodiment of the present utility model, in which the valve port of the pressure conversion device is in a closed state;

[0042] Figure 7 The partial structural schematic diagram of the glue coating device according to an embodiment of the present utility model, where the valve port is open and the pressure conversion device is in a constant pressure state;

[0043] Figure 8 The partial structural schematic diagram of the glue coating device according to an embodiment of the present utility model, where the valve port is open and the pressure conversion device is not in a constant pressure state.

[0044] Reference numerals:

[0045] The first pressure regulating valve 1; the second pressure regulating valve 2; the pneumatic return valve 3; the switching valve 4; the first air inlet end 41; the second air inlet end 42; the air outlet end 43; the exhaust valve 5; the first measuring device 6; the second measuring device 7; the third measuring device 8; the first pipeline 9; the second pipeline 10; the third pipeline 11; the air inlet pipeline 12; the solenoid valve 13; the glue spraying valve 14; the air source filter 15; the delivery pump 16; the motor 17; the glue liquid container 18;

[0046] The air inlet joint 100; the air inlet channel 110; the upper cover 120;

[0047] The upper main body 200; the second cavity 210; the air inlet interface 220; the limiting part 230; the sealing structure 240; the mounting hole 250; the shaft seal 260; the gasket 270; the snap ring 280; the passing hole 290;

[0048] The lower main body 300; the first cavity 310; the gap 311; the liquid inlet 320; the valve port 330; the return hole 340; the shoulder 350; the third annular groove 360; the annular boss 370; the clamping groove 380;

[0049] The thimble 400; the first sealing part 410; the first annular groove 411; the first sealing ring 412; the first rod part 420; the end part 421; the first bearing surface 430;

[0050] The piston 500; the second sealing part 510; the second annular groove 511; the second sealing ring 512; the second rod part 520; the second bearing surface 530;

[0051] The third sealing ring 600; the fourth sealing ring 700; the retaining ring 710;

[0052] The branch seat 800; the liquid channel 810; the glue inlet 811; the valve body installation cavity 820; the return channel 830; the fifth sealing ring 840. Detailed implementation manners

[0053] The concept and technical effects of the present utility model will be clearly and completely described below in conjunction with embodiments to fully understand the purpose, features, and effects of the present utility model. Obviously, the described embodiments are only a 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 scope of protection of the present utility model.

[0054] 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 positional relationship indicated is based on the orientation or positional relationship shown in the drawings. It 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.

[0055] In the description of the embodiments of the present utility model, if a certain feature is described as "set", "fixed", "connected", "installed" on another feature, it can be directly set, fixed, connected, or installed on another feature, or indirectly set, fixed, connected, or 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 present number. If it involves "above", "below", "within", it should be understood as including the present number. 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.

[0056] Reference Figure 1 and Figure 2 and, an embodiment of the first aspect of the present utility model provides a pressure conversion device, which is applicable to the glue liquid conveying system of a glue coating device, and includes a first pressure regulating valve 1, a second pressure regulating valve 2, a pneumatic return valve 3, and a switching valve 4.

[0057] The first pressure regulating valve 1 is adapted to connect to an air source and is used to regulate the output air pressure within a first air pressure range. The second pressure regulating valve 2 is adapted to connect to an air source and is used to regulate the output air pressure within a second air pressure range. The second pressure regulating valve 2 is independent of the first pressure regulating valve 1, and the second air pressure range is smaller than the first air pressure range. Thus, the first pressure regulating valve 1 can perform high-pressure regulation relative to the second pressure regulating valve 2, and the second pressure regulating valve 2 can perform low-pressure regulation relative to the first pressure regulating valve 1. Therefore, the first pressure regulating valve 1 can be a high-pressure regulating valve, and the second pressure regulating valve 2 can be a low-pressure regulating valve.

[0058] The pneumatic return valve 3 includes an air inlet interface 220, a liquid inlet 320, and a return hole 340. The liquid inlet 320 is adapted to communicate with the liquid channel 810 of the glue delivery system, and the return hole 340 is adapted to communicate with the return channel 830 for glue return. The switching valve 4 is connected to the output end of the first pressure regulating valve 1, the output end of the second pressure regulating valve 2, and the air inlet interface 220 of the pneumatic return valve 3. The switching valve 4 is used to switch the air inlet interface 220 to communicate with the output end of the first pressure regulating valve 1 or the output end of the second pressure regulating valve 2.

[0059] Wherein, the pneumatic return valve 3 is configured such that when the air inlet interface 220 communicates with the output end of the first pressure regulating valve 1, the liquid pressure at the liquid inlet 320 is greater than a first set value, the liquid inlet 320 and the return hole 340 are conducted; when the air inlet interface 220 communicates with the output end of the second pressure regulating valve 2, the liquid pressure at the liquid inlet 320 is greater than a second set value, the liquid inlet 320 and the return hole 340 are conducted; the first set value is greater than the second set value. In application, through the switching of the switching valve 4, the pneumatic return valve 3 can be quickly switched to communicate with the first pressure regulating valve 1 or the second pressure regulating valve 2, so as to realize the quick switching between high-pressure regulation and low-pressure regulation, thereby facilitating the quick switching of the opening pressure of the pneumatic return valve 3 and improving the switching efficiency.

[0060] Wherein, the first pressure regulating valve 1 is provided with a first air inlet and a first air outlet. The first air inlet is adapted to connect to an air source. The first pressure regulating valve 1 is configured to regulate the air pressure output from the first air outlet within a first air pressure range. The second pressure regulating valve 2 is provided with a second air inlet and a second air outlet. The second air inlet is adapted to connect to an air source. The second pressure regulating valve 2 is configured to regulate the air pressure output from the second air outlet within a second air pressure range.

[0061] The switching valve 4 can be a two-position three-way solenoid valve, having a first air inlet end 41, a second air inlet end 42, and an air outlet end 43. The first air inlet end 41 is connected to the first air outlet through a pipeline, and the second air inlet end 42 is connected to the second air outlet through a pipeline. The switching valve 4 is used to switch the air outlet end 43 to communicate with the first air inlet end 41 or the second air inlet end 42, so as to switch the air outlet end 43 to communicate with the first air outlet or the second air outlet, thereby quickly switching the first pressure regulating valve 1 or the second pressure regulating valve 2 to communicate with the pneumatic return valve 3, realizing the switching of the opening pressure of the pneumatic return valve 3, and thus quickly regulating the liquid pressure in the liquid channel 810.

[0062] Reference Figure 1 In some embodiments, an exhaust valve 5 is further connected between the second pressure regulating valve 2 and the switching valve 4. The second pressure regulating valve 2 and the first pressure regulating valve 1 can be connected to the same air source pipeline. When the switching valve 4 switches from the state where the first pressure regulating valve 1 communicates with the pneumatic return valve 3 to the state where the second pressure regulating valve 2 communicates with the pneumatic return valve 3, the air pressure can be quickly exhausted through the exhaust valve 5 to reduce the air pressure, improving the efficiency of low-pressure switching.

[0063] ReferenceFigure 1 In some embodiments, the pressure conversion device further includes at least one of a first measuring device 6, a second measuring device 7, and a third measuring device 8.

[0064] The first measuring device 6 is connected to the first pressure regulating valve 1 and is used to measure the output air pressure of the first pressure regulating valve 1, which is convenient for confirming the current pressure value. Specifically, the first measuring device 6 can be a voltmeter, which can intuitively reflect the current pressure value of the first pressure regulating valve 1.

[0065] The second measuring device 7 is connected to the second pressure regulating valve 2 and is used to measure the output air pressure of the second pressure regulating valve 2, which is convenient for confirming the current pressure. Specifically, the second measuring device 7 can be a voltmeter, which can intuitively reflect the current pressure value of the second pressure regulating valve 2.

[0066] The third measuring device 8 is connected between the air inlet interface 220 and the air outlet end 43 of the switching valve 4, and is used to measure the air pressure of the air inlet interface 220 of the pneumatic return valve 3, which is convenient for confirming the air pressure value of the current input to the pneumatic return valve 3. Specifically, the third measuring device 8 can be a voltmeter, which can intuitively reflect the current air pressure value of the input pneumatic return valve 3, so as to facilitate confirming the current working state of the pneumatic return valve 3. When there is an abnormal pressure, it can also be quickly identified through the reading of the pressure gauge.

[0067] Reference Figure 1 In some embodiments, the first air inlet end 41 of the switching valve 4 can be connected to the output end of the first pressure regulating valve 1 through the first pipeline 9, the second air inlet end 42 can be connected to the output end of the second pressure regulating valve 2 through the second pipeline 10, and the air outlet end 43 can communicate with the air inlet interface 220 of the pneumatic return valve 3 through the third pipeline 11. The first pipeline 9 can be connected with the first measuring device 6, the second pipeline 10 can be connected with the second measuring device 7, and the third pipeline 11 can be connected with the third measuring device 8. Thus, the first pressure regulating valve 1, the second pressure regulating valve 2, the switching valve 4, the pneumatic return valve 3, the first measuring device 6, the second measuring device 7, and the third measuring device 8 can be assembled to form a module for the glue conveying system, which is convenient for modular disassembly, loading, and maintenance.

[0068] The pressure conversion device can adjust the intake air pressure of the pneumatic return valve 3 through the switching valve 4, the first pressure regulating valve 1, and the second pressure regulating valve 2, so as to change the opening and closing pressure of the pneumatic return valve 3, and can achieve online adjustment. The adjustment method is convenient and reliable, and the accuracy is easy to control.

[0069] Reference Figures 1 to 5, in some embodiments, the pneumatic reflux valve 3 is provided with a valve port 330 communicating the liquid inlet 320 and the reflux hole 340. The opening and closing of the valve port 330 are driven by the pressure difference between the air source pressure of the air inlet interface 220 and the liquid pressure of the liquid inlet 320. When the valve port 330 is opened, a channel can be formed to communicate the liquid inlet 320 and the reflux hole 340. When the valve port 330 is closed, the channel is closed, realizing the conduction and blocking of the liquid inlet 320 and the reflux hole 340.

[0070] In some embodiments, the pneumatic reflux valve 3 includes a valve body, a thimble 400 and a piston 500, wherein:

[0071] The valve body has an inner cavity. One end of the valve body is provided with a liquid inlet 320 communicating with the inner cavity, and a valve port 330 is arranged at a set distance from the liquid inlet 320 in the inner cavity. A reflux hole 340 communicating with the inner cavity is also arranged on the side wall of the valve body. The reflux hole 340 penetrates the inner wall of the valve body corresponding to the position on the side 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 communicating with the inner cavity, and the air inlet interface 220 is used to connect to an air source.

[0072] The thimble 400 is arranged in the inner cavity. One end of the thimble 400 facing the liquid inlet 320 can abut against and block the valve port 330, and the thimble 400 is hermetically connected to the inner wall of the valve body on the side of the reflux hole 340 away from the valve port 330. A first pressure-bearing surface 430 for bearing fluid pressure is defined on the side of the thimble 400 facing the valve port 330. The thimble 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 through which fluid can flow is formed between the peripheral wall of the thimble 400 and the inner wall of the valve body corresponding to the position of the reflux hole 340. In the state where the valve port 330 is opened, the liquid inlet 320 communicates with the reflux hole 340 through the gap 311. Thus, liquid (such as adhesive) can flow into the gap 311 through the liquid inlet 320 and flow out through the reflux hole 340.

[0073] The piston 500 is arranged in the inner cavity and is located between the thimble 400 and the air inlet interface 220. The piston 500 is hermetically connected to the inner wall of the valve body. One end of the piston 500 abuts against the end of the thimble 400 away from the valve port 330. A second pressure-bearing surface 530 for bearing gas pressure is defined on the side of the piston 500 away from the thimble 400. 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.

[0074] 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 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 communicate the liquid inlet 320 and the return hole 340. During 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 communicated with the return hole 340, realizing liquid reflux. When the liquid pressure weakens and 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.

[0075] 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, easier to control the adjustment accuracy, and improves the stability and reliability.

[0076] Reference Figures 6 to 8 , when used in a glue application device, the pneumatic reflux valve 3 can be arranged in the adhesive delivery channel. The liquid inlet 320 is communicated with the liquid channel 810, the return hole 340 is communicated with the return channel 830, and the air inlet interface 220 is communicated with 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 is subjected to 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 and 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 7 、 Figure 8 ), when the valve port 330 is opened, the return hole 340 is communicated with the liquid inlet 320, and the liquid can enter the valve port 330 through the liquid inlet 320 and flow out from the return hole 340. The return hole 340 is used to communicate with the return channel 830 to realize the 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 to fall back to close the valve port 330 under the second acting force (referenceFigure 6 ).

[0077] Therefore, the opening pressure of the valve port 330 is determined by the air pressure introduced. When the air inlet interface 220 is connected to the output end of the first pressure regulating valve, when the hydraulic pressure of the liquid inlet 320 is greater than the first set value, the first force is greater than the second force, and the liquid can push the ejector pin 400 to move in the direction away from the valve port 330 to open the valve port 330, and connect the liquid inlet 320 and the reflux hole 340. When the air inlet interface 220 is connected to the output end of the second pressure regulating valve, when the hydraulic pressure of the liquid inlet 320 is greater than the second set value, the first force is greater than the second force, and the liquid can push the ejector pin 400 to move in the direction away from the valve port 330 to open the valve port 330, and connect the liquid inlet 320 and the reflux hole 340. Changing the air pressure of the gas introduced into the air inlet interface 220 can change the upper limit of the hydraulic pressure 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.

[0078] refer to Figures 1 to 3 In some embodiments, the pneumatic reflux valve 3 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, and 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.

[0079] 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 3.

[0080] 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 3. 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.

[0081] 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.

[0082] 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 .

[0083] refer to Figures 3 to 5 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.

[0084] refer to Figure 2 and Figure 3, 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.

[0085] Reference Figures 3 to 4 , in the pneumatic return valve 3 of some embodiments, the thimble 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 in 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, ensure that the liquid flows out through the return hole 340 after the valve port 330 is opened, and prevent 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.

[0086] 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 thimble 400 is slidably disposed in 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 end portion 421 of the first rod portion 420 is skewed and the valve port 330 is not tightly closed.

[0087] 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 is kept coaxial with the valve port 330, effectively avoiding the deflection of the end portion 421 of the first rod portion 420. 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 capable of effectively blocking the liquid entering from the liquid inlet 320 on the side of the return hole 340 facing away from the liquid inlet 320.

[0088] 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. 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.

[0089] Reference Figure 3 and Figure 5 Referring to and, in the pneumatic return valve 3 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 second sealing surface 530 is defined by the surface of the second sealing portion 510 and the second rod portion 520 on the side facing away from the thimble 400, 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 the contact area is small, which can reduce the friction force with the inner wall of the second cavity 210.

[0090] 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. 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 realize a sealed connection between the second sealing portion 510 and the inner wall of the second cavity 210, and be able to effectively block the incoming 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.

[0091] Reference Figure 3 and Figure 5 In some embodiments, a mounting 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 mounting hole 250 at one end facing away from the liquid inlet 320. The through hole 290 of the second cavity 210 communicates with the mounting hole 250 and is aligned with the thimble 400, so that the second rod portion 520 passes through the through hole 290 and the mounting 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 in the mounting hole 250. A mounting table for axially abutting against a side of the shaft seal 260 facing away from the lower main body 300 is provided in the mounting hole 250. And a gasket groove and a snap ring groove are provided on a side of the shaft seal 260 facing away from the mounting table. A gasket 270 is provided in the gasket groove, and a snap ring 280 is installed in the snap ring groove. The gasket 270 abuts against a side of the shaft seal 260 facing away from the mounting table, 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 the outer peripheral wall of the second rod portion 520, so that a seal between the second rod portion 520 and the mounting 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.

[0092] Reference Figures 2 to 4 In the above embodiments, a third annular groove 360 and / or a fourth annular groove may further be provided on an outer wall of the valve body corresponding to a proximal end of the liquid inlet 320, for playing a certain sealing role when the lower main body 300 is connected to a mounting structure (such as a branch seat 800).

[0093] In some embodiments, the third annular groove 360 is located between the liquid inlet 320 and the return hole 340. A third sealing ring 600 is provided in the third annular groove 360. The third sealing ring 600 can be an O-ring, forming a line seal.

[0094] 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.

[0095] In some embodiments, only one of the third sealing ring 600 and the fourth sealing ring 700 may be provided, which can also play a certain sealing role when connected with the branch seat 800.

[0096] refer to Figure 1 , Figure 2 and Figure 6 The second aspect of the utility model also provides a glue delivery system, which is used in glue coating equipment to deliver glue to a glue gun. The glue delivery system includes a branch seat 800, a delivery pump 16 and a pressure conversion device of any embodiment of the first aspect.

[0097] A liquid channel 810 and a reflux channel 830 are provided inside the branch seat 800. The liquid channel 810 is used to connect the glue container 18 and the glue gun, and the reflux channel 830 is suitable for connecting the glue container 18. The delivery pump 16 is connected to the liquid channel 810, and the delivery pump 16 is suitable for delivering the glue in the glue container 18 to the glue gun through the liquid channel 810. The delivery pump 16 can be a gear pump, which is driven to rotate by the motor 17 to realize the delivery of glue. The liquid inlet 320 of the pneumatic reflux valve 3 in the pressure conversion device is connected to the liquid channel 810, and the reflux hole 340 is connected to the reflux channel 830.

[0098] Among them, when the pneumatic reflux valve 3 is opened, a channel can be formed to connect the liquid inlet 320 and the reflux hole 340. When the valve port is opened to a greater extent, a larger channel can be formed. When the valve port is opened to a lesser extent, a smaller channel can be formed. When the valve port is closed, the channel is closed. For example, in some embodiments, the glue delivery system adopts the pneumatic reflux valve 3 in some of the aforementioned embodiments of the present application. When the ejector pin 400 opens the valve port 330, a channel can be formed between the ejector pin 400 and the valve port 330. When the distance between the ejector pin 400 and the valve port 330 is large, a larger channel is formed, and most of the liquid entering from the liquid inlet 320 can flow back through the reflux hole 340. When the distance between the ejector pin 400 and the valve port 330 is reduced, a smaller channel is formed, and a small part of the liquid can flow back. When the ejector pin 400 closes the valve port 330, the channel is closed and the liquid does not flow back.

[0099] During application, the opening pressure of the pneumatic return valve 3 can be quickly switched through a pressure conversion device, correspondingly enabling the liquid passage 810 to convey liquid under high pressure or low pressure. For example, after switching from high pressure to low pressure, the second pressure regulating valve 2 is communicated with the air inlet interface 220 of the pneumatic return valve 3. Under the action of the pressure difference, the pneumatic return valve 3 opens to form a larger passage, and most of the liquid in the liquid passage 810 flows back through the return passage 830, causing the hydraulic pressure to drop to the second set value. The liquid passage 810 maintains a low-pressure state. When switching from low pressure to high pressure, the first pressure regulating valve 1 is communicated with the air inlet interface 220 of the pneumatic return valve 3. The opened passage of the pneumatic return valve 3 is reduced or closed, and a small part of the liquid flows back or does not flow back, and the hydraulic pressure rises to the first set value, so that the hydraulic pressure in the liquid passage 810 is maintained at a high-pressure state for conveying. Thus, by switching the first pressure regulating valve 1 or the second pressure regulating valve 2 to communicate with the pneumatic return valve 3 through the switching valve 4, the rapid switching between high-pressure conveying and low-pressure conveying can be realized. Therefore, the switching of the pressure is convenient and fast.

[0100] Reference Figure 1 、 Figures 6 to 8 , in some embodiments, the manifold 800 is used for shunting and filtering in the glue conveying system. A liquid passage 810, a valve body installation cavity 820, and a return passage 830 are arranged inside the manifold 800. One end of the liquid passage 810 penetrates through the manifold 800 to form a glue inlet 811 for introducing glue. The pneumatic return valve 3 of the pressure conversion device can be connected to the valve body installation cavity 820 through the valve body, and can be connected by threads. For example, an external thread is provided on the outer wall of the lower main body 300 of the valve body, and an internal thread suitable for screwing with the external thread is provided in the valve body installation cavity 820, thereby realizing the threaded connection between the two. A third sealing ring 600 and / or a fourth sealing ring 700 are also arranged between the lower main 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 also provided between the port position of the valve body installation cavity 820 and the lower main body 300.

[0101] During the spraying process, the high-pressure fluid pumped by the conveying pump 16 enters the liquid passage 810 through the glue inlet 811, and thus enters the manifold 800 for conveying. The valve body installation cavity 820 is communicated with the liquid passage 810, the return passage 830 is communicated with the valve body installation cavity 820, and one end of the valve body of the pneumatic return valve 3 having the liquid inlet 320 is sealingly connected to the inner wall of the valve body installation cavity 820. The liquid inlet 320 is communicated with the liquid passage 810, and the return hole 340 is communicated with the return passage 830. When the liquid pressure does not reach the opening pressure of the pneumatic return valve 3, the first acting force exerted by the liquid in the liquid passage 810 on the first bearing surface 430 is not greater than the second acting force exerted by the gas entering from the air inlet interface 220 on the second bearing surface. The piston 500 remains in contact with the ejector pin 400 to close the valve port 330 (reference Figure 6 ), and the liquid is conveyed through the liquid passage 810.

[0102] 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, 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 branch seat 800, it first passes through the pneumatic return valve 3, 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 transported 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 can reach a constant pressure state under the action of air pressure (refer to Figure 7 ), 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 3 does not perform constant pressure adjustment, and all the liquid returns through the return valve (refer to Figure 8 ).

[0103] Moreover, as can be seen from the above, by switching the first pressure regulating valve or the second pressure regulating valve to communicate with the pneumatic return valve 3 through the pressure conversion device, thereby 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.

[0104] The high-pressure and low-pressure switching efficiency is improved through the pressure switching device. Among them, the pneumatic return valve 3 omits the setting of the 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 chamber and guarantee the spraying quality.

[0105] In the related art, when the glue spraying equipment stops, the system hydraulic pressure is in the high-pressure state during operation, resulting in unstable glue spraying of the glue gun when starting up again (such as excessive glue spraying amount), which not only causes waste of glue liquid but also affects the glue application effect. If the air source of the pneumatic return valve 3 is cut off after stopping work, the glue liquid in the glue liquid conveying system returns through the return valve, which will cause a certain time to boost the pressure to the working pressure when starting up again, resulting in the glue gun not being able to perform glue application work in time. The third aspect embodiment of the present invention also provides a glue application device that can effectively solve this problem.

[0106] Refer to Figure 1, the glue application device of the embodiment of the present utility model includes a glue gun and the glue liquid conveying system of the embodiment of the second aspect above. The glue gun includes a glue spraying valve 14, and the glue spraying valve 14 is communicated with a liquid channel 810 for spraying glue. During application, the switching of the liquid conveying pressure is facilitated through the glue liquid conveying system, so that the glue gun can be switched between the high-pressure spraying state and the low-pressure spraying state. Or, it can be switched to the low-pressure state during shutdown, so that when switching to the high-pressure state again after starting up in the low-pressure state, the pressure boosting speed can be increased, and the excessive spraying of glue due to excessive pressure during startup can be avoided, thereby improving the applicability of the glue application device.

[0107] In some embodiments, the glue application device further includes an air inlet pipeline 12 and a solenoid valve 13. The air inlet pipeline 12 is adapted to connect to an air source. The glue spraying valve 14 is communicated with the solenoid valve 13, and the solenoid valve 13 is communicated with the air inlet pipeline 12. The solenoid valve 13 realizes the on-off control of the glue output of the glue spraying valve 14 by controlling the air intake of the glue spraying valve 14. It can be understood that controlling the on-off of the glue outlet of the glue spraying valve 14 through air pressure is a commonly used means in the art, and the specific structure and pneumatic principle of the glue spraying valve 14 will not be elaborated here.

[0108] In some embodiments, the glue application device further includes an air source filter 15. The first pressure regulating valve 1 and the second pressure regulating valve 2 are respectively connected to the air inlet pipeline 12, and the air source filter 15 is connected to the air inlet pipeline 12 for filtering the gas passing through the air inlet pipeline 12 at the front ends of the first pressure regulating valve 1, the second pressure regulating valve 2, and the solenoid valve 13, which can reduce the impurities in the gas and reduce the probability of the impurities affecting the first pressure regulating valve 1, the second pressure regulating valve 2, and the solenoid valve 13.

[0109] The embodiments of the present application have been described in detail above with reference to the accompanying drawings. However, the present application is not limited to the above embodiments. Various changes can be made without departing from the purpose of the present application within the scope of knowledge possessed by those of ordinary skill in the art. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A pressure conversion device, characterized in that, In a glue solution delivery system applicable to a glue coating device, it includes: A first pressure regulating valve, adapted to connect to an air source and used to regulate the output air pressure within a first air pressure range; A second pressure regulating valve, adapted to connect to the air source and used to regulate the output air pressure within a second air pressure range. The second pressure regulating valve is independent of the first pressure regulating valve, and the second air pressure range is smaller than the first air pressure range; A pneumatic reflux valve, including an air inlet interface, a liquid inlet, and a reflux hole. The liquid inlet is adapted to communicate with the liquid channel of the glue solution delivery system, and the reflux hole is adapted to communicate with a reflux channel for glue solution reflux; A switching valve, connected to the output end of the first pressure regulating valve, the output end of the second pressure regulating valve, and the air inlet interface of the pneumatic reflux valve. The switching valve is used to switch the air inlet interface to communicate with the output end of the first pressure regulating valve or the output end of the second pressure regulating valve; Wherein, the pneumatic reflux valve is configured such that when the air inlet interface communicates with the output end of the first pressure regulating valve, the liquid pressure at the liquid inlet conducts the liquid inlet and the reflux hole when it is greater than a first set value; when the air inlet interface communicates with the output end of the second pressure regulating valve, the liquid pressure at the liquid inlet conducts the liquid inlet and the reflux hole when it is greater than a second set value; the first set value is greater than the second set value.

2. The pressure conversion device according to claim 1, wherein An exhaust valve is also connected between the second pressure regulating valve and the switching valve.

3. The pressure conversion device according to claim 1, characterized in that It also includes at least one of a first measuring device, a second measuring device, and a third measuring device; wherein, The first measuring device is connected to the first pressure regulating valve and used to measure the output air pressure of the first pressure regulating valve; The second measuring device is connected to the second pressure regulating valve and used to measure the output air pressure of the second pressure regulating valve; The third measuring device is connected between the air inlet interface and the outlet end of the switching valve and used to measure the air pressure input to the air inlet interface of the pneumatic reflux valve.

4. The pressure conversion device according to claim 1, characterized in that, The pneumatic reflux valve includes a valve body, a piston, and a thimble, wherein: The valve body has an inner cavity. One end of the valve body is provided with the liquid inlet communicating with the inner cavity, and the valve body is provided with a valve port at a position within the inner cavity at a set distance from the liquid inlet. A reflux hole communicating with the inner cavity is also provided on the side wall of the valve body. The reflux hole penetrates through the inner wall of the valve body corresponding to the position on the side of the valve port away from the liquid inlet. The other end of the valve body is provided with the air inlet interface communicating with the inner cavity; The thimble is arranged in the inner cavity. One end of the thimble facing the liquid inlet can abut against and block the valve port. The thimble is hermetically connected to the inner wall of the valve body on the side of the reflux hole away from the valve port. The thimble 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 thimble facing the valve port defines a first pressure-bearing surface for bearing fluid pressure. A gap through which fluid can flow is provided between the peripheral wall of the thimble corresponding to the position of the reflux hole and the inner wall of the valve body; 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. A second pressure-bearing surface for bearing gas pressure is defined on the side of the piston away from the ejector pin. 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 connect the liquid inlet and the return hole.

5. The pressure conversion device according to claim 4, characterized in that The valve body includes a lower body and an upper body, wherein: The inside of the lower body is hollow to form a first cavity. The lower body has opposite ends. The first cavity penetrates through the two ends of the lower body and forms the liquid inlet at one end. A raised shoulder is provided on the inner wall of the lower 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 body on the side of the valve port away from the liquid inlet. The upper body has opposite ends. The inside of the upper body is hollow to form a second cavity, and the second cavity penetrates through the two ends of the upper body. One end of the upper body is sealingly connected to one end of the lower body away from the liquid inlet. 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 body away from the lower body is adapted to be connected to an air inlet joint for accessing a gas source.

6. The pressure conversion device according to claim 1, wherein The switching valve is a two-position three-way solenoid valve, having a first air inlet end, a second air inlet end and an air outlet end. The first air inlet end is connected to the output end of the first pressure regulating valve through a first pipeline, the second air inlet end is connected to the output end of the second pressure regulating valve through a second pipeline, and the air outlet end is communicated with the air inlet interface. The switching valve is used to switch the communication between the air outlet end and the first air inlet end or the second air inlet end, so as to switch the communication between the air outlet end and the first pressure regulating valve or the second pressure regulating valve.

7. A glue solution conveying system is applied to a glue coating device to convey glue solution to a glue gun, and is characterized in that The glue liquid conveying system includes: A manifold block, internally provided with a liquid channel and a return channel. The liquid channel is used to connect a glue liquid container and a glue gun, and the return channel is adapted to connect the glue liquid container. A delivery pump, connected to the liquid channel. The delivery pump is adapted to convey the glue liquid in the glue liquid container to the glue gun through the liquid channel. The pressure conversion device according to any one of claims 1 to 6, wherein the liquid inlet of the pneumatic return valve is communicated with the liquid channel, and the return hole is communicated with the return channel.

8. A glue - applying device, characterized in that, It includes a glue gun and the glue liquid conveying system according to claim 7. The glue gun includes a glue spraying valve, and the glue spraying valve is communicated with the liquid channel for spraying glue.

9. The glue coating device according to claim 8, wherein It further includes an air inlet pipeline and a solenoid valve. The air inlet pipeline is adapted to connect to a gas source. The glue spraying valve is communicated with the solenoid valve, and the solenoid valve is communicated with the air inlet pipeline.

10. The gluing device according to claim 9, characterized in that, It further includes an air source filter. The first pressure regulating valve and the second pressure regulating valve are respectively connected to the intake pipeline, and the air source filter is connected to the intake pipeline for filtering the gas passing through the intake pipeline at the front ends of the first pressure regulating valve, the second pressure regulating valve and the solenoid valve.

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