Air-free portable spray gun

Abstract

The utility model discloses an airless portable spray gun, which solves the problem that the spraying effect is influenced by the movement frequency of a piston in the existing airless portable spray gun. The airless portable spray gun comprises a machine shell, a liquid pot, a nozzle, a pump body, a driving mechanism and a liquid outlet valve, the nozzle is arranged at the front end of the machine shell, the pump body comprises a pump cavity, the liquid inlet end of the pump cavity is communicated with the liquid pot, and the liquid outlet end of the pump cavity is communicated with the liquid outlet valve through a first check valve. The liquid outlet valve comprises a valve body with a buffering cavity, a valve seat, a valve head and a spring, the valve seat, the valve head and the spring are arranged in the valve body, a liquid outlet hole communicated with the nozzle is formed in the valve seat, the spring acts on the valve body to close the liquid outlet hole, and the pump body extracts liquid from the liquid pot and presses the liquid into the buffering cavity. And after the pressure of the valve head in the buffer cavity exceeds the preset liquid outlet pressure, the valve head is opened, so that liquid in the buffer cavity is sprayed out of the nozzle through the liquid outlet hole.

Description

Technical Field

[0001] The utility model relates to the field of spray guns, in particular to an airless portable spray gun. Background Art

[0002] Airless portable spray gun, also known as high-pressure airless portable spray gun, is a spray gun that is powered by a battery pack and uses a high-pressure plunger pump to pressurize paint, coatings, etc. to form high-pressure paint for spraying.

[0003] The spraying effect of the existing airless portable spray gun is often affected by the movement frequency of the plunger pump piston. The higher the piston movement frequency, the more uniform the liquid sprayed from the nozzle, the less intermittent spraying, and the better the spraying effect; if the piston movement frequency is low, the intermittent spraying is more obvious and the spraying effect is not improved. Utility Model Content

[0004] The technical problem to be solved by the utility model is to reduce the influence of the piston movement frequency on the spraying effect, reduce the degree of the intermittent spraying at the low working frequency of the piston, and improve the spraying quality.

[0005] In order to achieve the above technical objectives, the utility model provides an airless portable spray gun, comprising a casing, a liquid pot, a nozzle, a pump body, a driving mechanism and a liquid outlet valve, the nozzle being arranged at the front end of the casing, the pump body comprising a pump chamber, the liquid inlet end of the pump chamber being connected to the liquid pot, the liquid outlet end of the pump chamber being connected to the liquid outlet valve through a first check valve, the liquid outlet valve comprising a valve body having a buffer chamber and a valve seat, a valve head and a spring arranged in the valve body, the valve seat being provided with a liquid outlet hole connected to the nozzle, the spring acting on the valve body to close the liquid outlet hole, the driving mechanism driving the pump body to work to extract liquid from the liquid pot and press it into the buffer chamber, the valve head opening after the pressure in the buffer chamber exceeds a preset liquid outlet pressure so that the liquid in the buffer chamber is sprayed out from the nozzle through the liquid outlet hole.

[0006] Preferably, the valve seat includes a valve seat body and a tail seat, the tail seat is detachably fixedly connected to the valve seat body, the tail seat is installed at one end of the valve seat body away from the nozzle, and a limiting cavity for limiting the valve head and the spring is formed between the tail seat and the valve seat body, and the valve head is movable in the limiting cavity.

[0007] Preferably, the tail seat is hollow to form a liquid inlet hole connected to the liquid outlet hole, and the valve head seals the liquid inlet hole to close the liquid outlet hole.

[0008] Preferably, the valve seat also includes a movable rod, which is slidably disposed in the valve seat body, and the movable rod and the valve seat body are circumferentially sealed to form a sealed cavity between the movable rod and the tail seat, and the spring is disposed in the sealed cavity, one end of the spring abuts against the tail seat, and the other end abuts against the movable rod, and the valve head is fixed on the movable rod, and the valve head includes a conical head, and a portion of the head extends into the liquid outlet to close the liquid outlet.

[0009] Preferably, a fixing frame is provided at one end of the valve body close to the pump body, and the valve body also includes a movable rod, the valve head is fixed on the movable rod, the fixing frame is provided with a blind hole, one end of the movable rod can be movably extended into the blind hole, one end of the spring abuts on the fixing frame, and the other end abuts on the movable rod, and the valve head includes a conical head, a part of which extends into the liquid outlet to close the liquid outlet.

[0010] Preferably, the pump body comprises a pump chamber, the driving mechanism acts on the pump body to change the size of the pump chamber, and the ratio of the liquid volume of the pump chamber filled with liquid to the volume of the buffer chamber that can accommodate liquid is in the range of 1:1 to 1:50.

[0011] Preferably, the pump body also includes a pump chamber and a pressure relief channel, the pressure relief channel includes a first channel connected to the pump chamber and a second channel connected to the liquid pot, a pressure relief valve is provided between the first channel and the second channel, and a preset pressure relief pressure of the pressure relief valve is greater than the preset liquid outlet pressure of the valve body.

[0012] Preferably, the pressure relief valve is arranged in the casing, and the pressure relief valve includes a pressure relief valve housing, a pressure relief tail seat, a pressure relief valve stem, a pressure relief valve head and a pressure relief spring. The pressure relief valve housing is provided with a first pressure relief hole and a second pressure relief hole that are interconnected, the first pressure relief hole is connected to the first channel, and the second pressure relief hole is connected to the second channel, the pressure relief valve stem is movably mounted on the pressure relief tail seat, one end of the pressure relief spring abuts on the pressure relief tail seat, and the other end abuts on the pressure relief valve stem, the pressure relief valve head is fixed on the pressure relief valve stem, a conical surface is formed on the pressure relief valve head, the spring acts on the pressure relief valve stem to press the conical surface against the first pressure relief hole, and the pressure in the buffer chamber is sealed from the pressure relief valve head and the pump chamber when the pressure is less than the preset pressure relief pressure.

[0013] Preferably, the pressure relief valve also includes a pressure relief valve cover, the tail end of the pressure relief valve stem extends in a direction away from the pressure relief channel and passes through the pressure relief valve cover, and the tail end of the pressure relief valve stem is operably installed with a pressure relief component, and the pressure relief component is operated to make the pressure relief valve head open the first pressure relief hole, so that the pressure relief valve actively relieves pressure.

[0014] Preferably, the pressure relief component includes a knob, which is covered on the pressure relief valve cover and rotates relative to the pressure relief valve cover, one of the pressure relief valve cover and the knob is provided with a supporting portion, and the other is provided with an abutting portion, the pressure relief spring acts on the knob to make the abutting portion abut against the supporting portion, the supporting portion includes a first supporting portion and a second supporting portion, the pressure relief valve actively relieves pressure when the abutting portion abuts against the first supporting portion, and the pressure relief valve stops actively relieving pressure when the abutting portion abuts against the second supporting portion.

[0015] Preferably, the support portion further includes a spacing portion provided between the first support portion and the second support portion, and a surface of the spacing portion gradually changes from the first support portion to the second support portion.

[0016] Preferably, the abutting portion is in a convex arc shape, and the second supporting portion is in a concave arc shape adapted to the abutting portion.

[0017] Preferably, at least a portion of the first supporting portion is in a concave arc shape that is compatible with the abutting portion.

[0018] After adopting the above technical solution, the utility model has the following beneficial effects.

[0019] 1. The utility model proposes an airless portable spray gun, which forms a buffer chamber in the valve body of the liquid outlet valve, so that the sprayed liquid can be pre-pressurized in the buffer chamber before being sprayed, and a large amount of spraying liquid is stored in the buffer chamber with uniform liquid pressure. The pressure of the sprayed liquid can still be maintained during the gap when the pump body draws liquid, thereby reducing the degree of intermittent spraying and improving the spraying effect of the spray gun.

[0020] 2. By arranging a tail seat at the end of the valve seat away from the nozzle, the valve head and the spring are limited between the valve seat body and the tail seat, so that the size of the valve seat can be reduced, the available volume of the buffer chamber can be increased, and the size of the liquid outlet valve can be reduced under the premise of meeting the design requirements, saving the material cost of the liquid outlet valve; at the same time, the tail seat and the valve seat body are detachably fixedly connected, which is convenient for the disassembly and internal cleaning of the valve seat; furthermore, a limiting cavity for limiting the valve head and the spring is formed between the tail seat and the valve seat body, and the valve head can move in a limited manner in the limiting cavity, so that the valve seat, the valve head and the spring form a detachable integrated structure, the valve head and the spring are not easily lost when the valve seat is disassembled, and it is more convenient for the operator to assemble the valve seat and the valve body.

[0021] 3. By forming a liquid inlet hole on the tail seat, the liquid pressure in the buffer chamber can directly act on the valve head, the opening method of the valve head is simpler, and the spray sensitivity of the spray gun is higher.

[0022] 4. A movable rod is arranged in the valve body, and the movable rod and the valve seat body are circumferentially sealed to form a sealed cavity between the movable rod and the tail seat. The spring is arranged in the sealed cavity to prevent the liquid from contacting the spring and causing the spring to rust, and also to prevent the liquid from contacting rust and causing the contaminated liquid to affect the spraying effect or block the nozzle.

[0023] 5. One end of the movable rod is movably connected to the fixed frame, and the other end is fixed with a valve head. The valve head adopts a conical head to achieve the sealing and liquid discharge of the liquid outlet valve, thereby achieving the sealing and liquid discharge of the liquid outlet valve. The structure is simple and reliable, and the cost is low.

[0024] 6. By setting the volume ratio of the pump chamber and the buffer chamber, the buffer chamber can obtain better liquid storage and buffering effects, thereby improving the spraying quality of the spray gun.

[0025] 7. By setting a pressure relief channel in the pump body, when the pressure in the pump chamber is too high, the liquid in the pump chamber directly flows back to the liquid pot through the pressure relief channel, thereby avoiding excessive working resistance of the driving mechanism causing it to heat up.

[0026] 8. The pressure relief valve head adopts a conical head to achieve the sealing and liquid discharge of the pressure relief valve. The structure is simple and reliable with low cost.

[0027] 9. The pressure relief valve also includes a pressure relief valve cover. The tail end of the pressure relief valve stem extends in a direction away from the pressure relief channel and passes through the pressure relief valve cover. The tail end of the pressure relief valve stem is operably installed with a pressure relief component. The pressure relief component is operated to release the pressure of the pressure relief valve head on the first pressure relief hole, and the pressure relief valve actively relieves pressure. With this arrangement, the operator can actively relieve pressure on the pressure relief valve to avoid the buffer chamber remaining in a high-pressure state after the airless portable spray gun is shut down.

[0028] 10. The pressure relief component includes a knob, which is covered on the pressure relief valve cover and rotates relative to the pressure relief valve cover. A supporting portion is provided on one of the pressure relief valve cover and the knob, and an abutting portion is provided on the other. The pressure relief spring acts on the knob to make the abutting portion abut against the supporting portion. The supporting portion includes a first supporting portion and a second supporting portion. When the abutting portion abuts against the first supporting portion, the pressure relief valve actively relieves pressure, and when the abutting portion abuts against the second supporting portion, the pressure relief valve stops actively relieving pressure. With such an arrangement, an operator can realize active pressure relief or stop pressure relief of the pressure relief valve by turning the knob to make the abutting portion abut against different positions of the supporting portion, and the operation of the pressure relief component is simpler. At the same time, the knob occupies less space than a pull rod or a lever, thereby reducing the outer dimensions of the airless portable spray gun.

[0029] 11. A spacer is provided between the first support portion and the second support portion, and the surface of the spacer changes gradually from the first support portion to the second support portion. In this way, the knob can cooperate with the spacer to achieve switching between the first support portion and the second support portion during the rotation of the knob. The operator does not need to lift the knob when turning the knob to achieve the position switching of the abutment portion on the support portion, and the operation of active pressure relief of the pressure relief component is simpler.

[0030] 12. The abutting portion is in the shape of a convex arc surface, and the second supporting portion is in the shape of a concave arc surface adapted to the abutting portion. With such an arrangement, the abutting portion can slide more smoothly between the first supporting portion and the second supporting portion. At the same time, the shapes of the second supporting portion and the abutting portion are adapted to each other, so that the abutting portion and the second supporting portion can be better positioned when the pressure relief valve stops relieving pressure, thereby reducing or avoiding the string movement between the two.

[0031] 13. At least part of the first supporting portion is in the shape of a concave arc surface adapted to the abutting portion. With such a configuration, the abutting portion can be positioned when abutting against the first supporting portion, thereby reducing or avoiding the abutting portion from sliding off the first supporting portion during active pressure relief.

[0032] These features and advantages of the present invention will be disclosed in detail in the following specific implementation manners and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a partial cross-sectional schematic diagram of a spray gun in an embodiment of the utility model;

[0034] Figure 2 It is a schematic diagram of a pump body and a valve body in an embodiment of the utility model;

[0035] Figure 3 It is a cross-sectional schematic diagram of a pump body and a valve body in an embodiment of the utility model;

[0036] Figure 4 Another cross-sectional schematic diagram of the pump body and the valve body in the embodiment of the utility model;

[0037] Figure 5 Another cross-sectional schematic diagram of the pump body and the valve body in the embodiment of the utility model;

[0038] Figure 6 It is a cross-sectional schematic diagram of the pressure relief channel and the pressure relief valve in the embodiment of the utility model;

[0039] Figure 7 It is a cross-sectional schematic diagram of another pressure relief valve in an embodiment of the utility model;

[0040] Figure 8 for Figure 7 Schematic diagram of a valve cover of a pressure relief valve;

[0041] Fig. 9 for Figure 7 Schematic diagram of the knob of the pressure relief valve;

[0042] Reference numerals:

[0043] 100, housing, 110, liquid pot, 120, nozzle, 130, driving mechanism, 140, pump body, 141, pump chamber; 142, pressure relief valve mounting portion;

[0044] 200, liquid outlet valve, 201, first check valve, 210, valve body, 211, buffer chamber, 212, fixing frame, 220, valve seat, 221, valve seat body, 222, tail seat, 223, limit chamber, 224, liquid outlet hole, 225, liquid inlet hole, 230, valve head, 240, spring, 250, valve plate, 260, movable rod, 270, pressure relief channel, 271, first channel, 272, second channel, 28 0. Pressure relief valve, 281. Pressure relief valve housing, 2811. First pressure relief hole, 2812. Second pressure relief hole, 282. Pressure relief tail seat, 283. Pressure relief valve stem, 284. Pressure relief valve head, 285. Pressure relief spring, 286. Pressure relief valve cover, 290. Pressure relief component, 291. Knob, 292. Support portion, 2921. First support portion, 2922. Second support portion, 2923. Spacer portion, 293. Abutment portion. DETAILED DESCRIPTION

[0045] The following is an explanation and description of the technical scheme of the embodiment of the utility model in conjunction with the drawings of the embodiment of the utility model, but the following embodiment is only a preferred embodiment of the utility model, not all. Based on the embodiment in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the utility model.

[0046] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0047] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" and "several" mean two or more, unless otherwise clearly defined.

[0048] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0050] Embodiment 1:

[0051] like Figures 1 to 5 As shown, an airless portable spray gun proposed in an embodiment of the utility model comprises a housing 100, a liquid pot 110, a nozzle 120, a pump body 140, a driving mechanism 130 and a liquid outlet valve 200. The nozzle 120 is arranged at the front end of the housing 100, and the liquid pot 110 is used to store the liquid to be sprayed. The pump body 140 comprises a pump chamber 141, the liquid inlet end of the pump chamber 141 is connected to the liquid pot 110 through a first check valve 201, and the liquid outlet end of the pump chamber 141 is connected to the liquid outlet valve 200 through a second check valve 202. The liquid outlet valve 200 comprises a valve body 210 having a buffer chamber 211, a valve seat 220, a valve head 230 and a spring 240 arranged in the valve body 210, a liquid outlet hole 224 connected to the nozzle 120 is arranged on the valve seat 220, and the spring 240 acts on the valve head 230 to make the valve head 230 close the liquid outlet hole 224. The driving mechanism 130 drives the pump body 140 to extract liquid from the liquid pot 110 and press it into the buffer chamber 211. The valve head 230 opens after the pressure in the buffer chamber 211 exceeds the preset liquid outlet pressure to allow the liquid in the buffer chamber 211 to be sprayed out from the nozzle 120 through the liquid outlet hole 224.

[0052] By forming a buffer chamber 211 in the valve body 210 of the liquid outlet valve 200, the sprayed liquid is pre-pressurized in the buffer chamber 211 before being sprayed, and a large amount of spraying liquid is stored in the buffer chamber 211 with uniform liquid pressure. The pressure of the sprayed liquid can still be maintained during the gap when the pump body 140 draws liquid, thereby reducing the degree of spraying intermittently and improving the spraying effect of the spray gun.

[0053] The driving mechanism 130 includes a piston, which reciprocates in the pump body 140 to change the size of the pump chamber 141. The volume of the pump chamber 141 increases, and liquid is drawn from the liquid pot 110. The second check valve 202 restricts the liquid in the liquid outlet valve 200 from flowing into the pump chamber 141; the volume of the pump chamber 141 decreases, and the liquid in the pump chamber 141 is pressed into the liquid outlet valve 200. The first check valve 201 restricts the liquid in the pump chamber 141 from flowing into the liquid pot 110. The driving mechanism 130 is a volume change pump, such as a plunger pump, a piston pump, a gear pump, a diaphragm pump, and a screw pump.

[0054] Preferably, in this embodiment, a groove is provided on the outer circumference of the valve seat 220, and a sealing ring is installed in the groove. The sealing ring forms a circumferential seal between the valve seat 220 and the valve body 210, thereby preventing the liquid in the buffer chamber 211 from leaking through the gap between the valve seat 220 and the valve body 210.

[0055] In order to make the buffer chamber 211 obtain better liquid storage and buffering effect, it is preferred in this embodiment that the ratio of the volume filled with liquid in the pump chamber 141 to the volume that can accommodate liquid in the buffer chamber 211 is in the range of 1:1 to 1:50. If the buffer chamber 211 is set too large, the liquid in the buffer chamber 211 cannot be discharged after the operation is completed and the spraying is completed, which will cause waste; if the buffer chamber 211 is set too small, the liquid storage and buffering effect of the buffer chamber 211 will be affected. By setting the volume ratio of the pump chamber 141 and the buffer chamber 211, the buffer chamber 211 can obtain better liquid storage and buffering effects, thereby improving the spraying quality of the spray gun.

[0056] More preferably, in this embodiment, the ratio of the volume of liquid filled in the pump chamber 141 to the volume of liquid that can be accommodated in the buffer chamber 211 is in the range of 1:10 to 1:40; more preferably, the volume ratio is in the range of 1:1 to 1:30; more preferably, the volume ratio is in the range of 1:1 to 1:20.

[0057] Embodiment 2:

[0058] like Figure 3As shown, based on embodiment one, in this embodiment, a fixing frame 212 is provided at one end of the valve body 210 close to the pump body 140, and the fixing frame 212 is used to support the first check valve 201. At least one liquid inlet hole 225 is hollowed out on the fixing frame 212, and the liquid outlet valve 200 also includes a movable rod 260. A blind hole is provided at one end of the fixing frame 212 away from the first check valve 201, and one end of the movable rod 260 can be movably extended into the blind hole, and a valve head 230 is fixed on the other end. One end of the spring 240 presses on the fixing frame 212, and the other end presses on the movable rod 260, thereby pressing the valve head 230 against the liquid outlet hole 224. The valve head 230 includes a conical head, a valve plate 250 is provided on the liquid outlet 224, the valve plate 250 is circumferentially sealed with the liquid outlet 224, a through hole is provided in the valve plate 250, and a part of the conical head extends into the through hole to enable the valve head 230 to close the liquid outlet 224, and the part of the conical head is located in the buffer chamber 211.

[0059] The pressure of the liquid in the buffer chamber 211 is applied circumferentially to the conical head located in the buffer chamber 211, and the pressure is decomposed into a force in the direction away from the liquid outlet hole 224 and a force in the axial direction of the valve head 230. The circumferential forces in the axial direction of the valve head 230 offset each other. After the superposition of the circumferential forces away from the liquid outlet hole 224 exceeds the preset liquid outlet pressure, the liquid pushes the valve head 230 to move in the direction away from the liquid outlet valve, and the liquid enters the nozzle from between the valve head 230 and the liquid outlet hole 224 and is ejected.

[0060] A fixing frame 212 is provided at one end of the valve body 210 close to the pump body 140, one end of the movable rod 260 is movably connected to the fixing frame 212, and a valve head 230 is fixed on the other end. The valve head 230 adopts a conical head to achieve the sealing and liquid discharge of the liquid outlet valve 200, thereby achieving the sealing and liquid discharge of the liquid outlet valve 200, with a simple and reliable structure and low cost.

[0061] Embodiment three:

[0062] like Figures 4 to 5As shown, based on Example 1, different from Example 2, in this embodiment, the valve seat 220 includes a valve seat body 221 and a tail seat 222, and the tail seat 222 is detachably fixedly connected to the valve seat body 221. The tail seat 222 is installed at one end of the valve seat body 221 away from the nozzle 120, and a limiting cavity 223 for limiting the valve head 230 and the spring 240 is formed between the tail seat 222 and the valve seat body 221, and the valve head 230 can move in a limited manner in the limiting cavity 223. By arranging a tail seat 222 at one end of the valve seat 220 away from the nozzle 120, the valve head 230 and the spring 240 are limited between the valve seat body 221 and the tail seat 222, so that the size of the valve seat 220 can be reduced, the available volume of the buffer chamber 211 can be increased, and the size of the liquid outlet valve 200 can be reduced on the premise of meeting the design requirements, saving the material cost of the liquid outlet valve 200; at the same time, the tail seat 222 and the valve seat body 221 are detachably fixedly connected, which is convenient for the disassembly and internal cleaning of the valve seat 220; furthermore, a limiting cavity 223 for limiting the valve head 230 and the spring 240 is formed between the tail seat 222 and the valve seat body 221, and the valve head 230 can be limitedly movable in the limiting cavity 223, so that the valve seat 220, the valve head 230 and the spring 240 form a detachable integrated structure, the valve head 230 and the spring 240 are not easily lost when the valve seat 220 is disassembled, and it is more convenient for operators to assemble the valve seat 220 and the valve body 210.

[0063] In one embodiment, Figure 4 As shown, the tail seat 222 is hollow to form a liquid inlet hole 225 connected to the liquid outlet hole 224, one end of the spring 240 abuts against the valve seat body 221, and the other end acts on the valve head 230 to make the valve head 230 seal the liquid inlet hole 225 and close the liquid outlet hole 224. The valve head 230 is a sphere, the diameter of the valve head 230 is greater than the diameter of the liquid inlet hole 225, and part of the valve head 230 enters the liquid inlet hole 225 to achieve sealing. Liquid pressure is applied to the valve head 230 entering the liquid inlet hole 225, and when the pressure is greater than the preset liquid outlet pressure, the valve head 230 is pushed away from the liquid inlet hole 225. In some other embodiments, the valve head 230 can also be a cone or at least part of the valve head 230 is a cone.

[0064] By forming the liquid inlet hole 225 on the tail seat 222, the liquid pressure in the buffer chamber 211 can directly act on the valve head 230, the opening method of the valve head 230 is simpler, and the spray gun has a higher spray sensitivity.

[0065] In another embodiment, Figure 5As shown, the liquid outlet valve 200 further includes a movable rod 260, which is slidably disposed in the valve seat body 221, and a sealing ring is circumferentially disposed on the movable rod 260. The movable rod 260 and the valve seat body 221 are circumferentially sealed to form a sealed cavity between the movable rod 260 and the tail seat 222. The spring 240 is disposed in the sealed cavity, and one end of the spring 240 abuts on the tail seat 222, and the other end abuts on the movable rod 260. The valve head 230 is fixed on the movable rod 260, and the valve head 230 includes a conical head, and a part of the conical head extends into the liquid outlet hole 224 to achieve sealing. Among them, the liquid inlet hole 225 is disposed on the side of the valve seat body 221 and is connected to the liquid outlet hole 224.

[0066] The pressure of the liquid in the buffer chamber 211 is applied circumferentially to the conical head, and the pressure is decomposed into a force in the direction away from the liquid outlet hole 224 and a force in the axial direction of the valve head 230. The circumferential forces in the axial direction of the valve head 230 offset each other. After the superposition of the circumferential forces away from the liquid outlet hole 224 exceeds the preset liquid outlet pressure, the liquid pushes the valve head 230 to move in the direction away from the liquid outlet valve, thereby achieving spraying.

[0067] A movable rod 260 is provided in the liquid outlet valve 200, and the movable rod 260 and the valve seat body 221 are circumferentially sealed to form a sealed cavity between the movable rod 260 and the tail seat 222. The spring 240 is arranged in the sealed cavity to prevent liquid from contacting the spring 240 and causing the spring 240 to rust, and also to prevent liquid from contacting rust and causing contaminated liquid to affect the spraying effect or clog the nozzle 120.

[0068] Embodiment 4:

[0069] like Figure 2 , Figure 6 , Figure 7 As shown, based on embodiments one, two and three, in this embodiment, the pump body 140 also includes a pressure relief channel 270, the pressure relief channel 270 includes a first channel 271 connected to the pump chamber 141 and a second channel 272 connected to the liquid pot 110, and a pressure relief valve 280 is provided between the first channel 271 and the second channel 272, and the preset pressure relief pressure of the pressure relief valve 280 is greater than the preset liquid outlet pressure of the liquid outlet valve 200.

[0070] Specifically, the pump body 140 is provided with a pressure relief valve installation portion 142 for installing a pressure relief valve 280, a first channel 271 is communicated between the pump chamber 141 and the pressure relief valve installation portion 142, a second channel 272 is communicated between the liquid pot 110 and the pressure relief valve installation portion 142, and the pressure relief valve 280 seals the first channel 271 to limit the liquid in the pump chamber 141 from flowing into the liquid pot. The pressure relief valve 280 opens after the pressure exceeds the preset pressure relief pressure, and the pressure relief valve 280 opens to allow the liquid in the pump chamber 141 to flow back into the liquid pot 110, thereby preventing the liquid pressure in the buffer chamber 211 from being too high.

[0071] By setting a pressure relief channel 270 in the pump body 140, when the pressure in the buffer chamber 211 is too high, the liquid in the pump chamber 141 directly flows back to the liquid pot 110 through the pressure relief channel 270, thereby avoiding the driving mechanism 130 from heating up due to excessive working resistance.

[0072] In one embodiment, the pressure relief valve 280 is disposed in the housing 100 and is detachably fixedly connected to the third connection end 213. The pressure relief valve 280 includes a pressure relief valve housing 281, a pressure relief tail seat 282, a pressure relief valve stem 283, a pressure relief valve head 284 and a pressure relief spring 285. The pressure relief valve housing 281 is provided with a first pressure relief hole 2811 and a second pressure relief hole 2812 which are interconnected. The first pressure relief hole 2811 is opposite to the first pressure relief channel 270, and the second pressure relief hole 2812 is connected to the second channel 272. The pressure relief valve stem 283 is movably mounted on the pressure relief tail seat 282. One end of the pressure relief spring 285 abuts on the pressure relief tail seat 282, and the other end abuts on the pressure relief valve stem 283. The pressure relief valve head 284 is fixed on the pressure relief valve stem 283. The pressure relief spring 285 has an elastic force acting on the pressure relief valve stem 283 so that the pressure relief valve head 284 abuts on the first pressure relief hole 2811 to achieve sealing, thereby preventing the liquid in the buffer cavity from leaking from the pressure relief channel 270. The elastic force of the pressure relief spring 285 acting on the pressure relief valve head 284 determines the magnitude of the pressure relief pressure. When the liquid pressure in the buffer chamber exceeds the pressure relief pressure, the liquid pushes the pressure relief valve head 284 to move, so that the liquid in the buffer chamber enters from the first channel 271 and is discharged into the liquid pot from the second channel 272 through the first pressure relief hole 2811 and the second pressure relief hole 2812.

[0073] Among them, a pressure relief valve plate 286 is further provided at one end of the pressure relief valve 280 close to the first channel 271. The pressure relief valve plate 286 is provided between the first pressure relief hole 2811 and the pressure relief valve head 284. The pressure relief valve plate 286 is circumferentially sealed with the pressure relief valve housing 281, and the pressure relief valve head 284 presses the pressure relief valve plate 286 against the first pressure relief hole 2811. A conical surface is formed on the pressure relief valve head 284, and the conical surface presses against the first pressure relief hole 2811, so that the pressure relief valve head 284 and the pump chamber 141 are sealed when the pressure in the pump chamber 141 is less than the preset pressure relief pressure.

[0074] In order to achieve operable active pressure relief, in one embodiment, as Figure 6 , Figure 7As shown, the pressure relief valve 280 also includes a pressure relief valve cover 286, the tail end of the pressure relief valve stem 283 extends in a direction away from the pressure relief channel 270 and passes through the pressure relief valve cover 286, and the tail end of the pressure relief valve stem 283 is operably installed with a pressure relief component 290. The operator operates the pressure relief component 290 to drive the tail end of the pressure relief valve stem 283 to move in a direction away from the pressure relief channel 270 to drive the pressure relief valve head 284 to open the first pressure relief hole 2811, so that the pressure relief valve 280 actively releases pressure. In this way, the operator can actively release pressure on the pressure relief valve 280 to prevent the buffer chamber 211 from remaining in a high-pressure state after the airless portable spray gun is turned off.

[0075] In a preferred embodiment, the pressure relief component 290 is a pull rod or a lever, and the operator achieves active pressure relief by pulling or levering the pressure relief component 290. The force direction of the pull rod or the lever is parallel to the movement direction of the pressure relief valve stem 283, so that the operator can perform active pressure relief operations more intuitively.

[0076] In another preferred embodiment, Figure 7 , Figure 8 , Fig. 9 As shown, the pressure relief component 290 includes a knob 291, which covers the pressure relief valve cover 286 and can rotate relative to the pressure relief valve cover 286. The pressure relief valve cover 286 is provided with a support portion 292, and the knob 291 is provided with an abutment portion 293. The pressure relief spring 285 acts on the knob 291 to make the abutment portion 293 abut against the support portion 292. The support portion 292 includes a first support portion 2921 and a second support portion 2922. The first support portion 2921 and the second support portion 2922 respectively support the abutment portion 293 at different positions. When the abutment portion 293 abuts against the first support portion 2921, the pressure relief valve 280 actively relieves pressure. When the abutment portion 293 abuts against the second support portion 2922, the pressure relief valve 280 stops actively relieving pressure.

[0077] It is understandable that in some other embodiments, the abutment portion 293 may also be provided on the pressure relief valve cover 28 , and the support portion 292 may also be provided on the knob 291 .

[0078] With such arrangement, the operator can realize active pressure relief or stop pressure relief of the pressure relief valve 280 by turning the knob 291 to make the abutment portion 293 abut against different positions of the support portion 292, and the operation of the pressure relief component 290 is easier; at the same time, the knob 291 occupies less space than the pull rod or the lever, thereby reducing the outer dimensions of the airless portable spray gun.

[0079] There are through holes on the tail end of the pressure relief valve stem 283 and the knob 291 , and the rotation 291 drives the pressure relief valve stem 283 to move by inserting the positioning pin into the through holes of the two.

[0080] Preferably, in this embodiment, the support portion 292 further includes a spacer portion 2923 disposed between the first support portion 2921 and the second support portion 2922 , and a surface of the spacer portion 2923 gradually changes from the first support portion 2921 to the second support portion 2922 .

[0081] With such arrangement, the knob 291 can cooperate with the spacer portion 2923 to achieve switching between the first support portion 2921 and the second support portion 2922 during the rotation of the knob 291. The operator can switch the position of the abutment portion 293 on the support portion 292 without having to lift the knob 291 during the rotation of the knob 291, and the operation of active pressure relief of the pressure relief component 290 is simpler.

[0082] Preferably, in this embodiment, the abutting portion 293 is in a convex arc shape, and the second supporting portion 2922 is in a concave arc shape adapted to the abutting portion 293 .

[0083] With such arrangement, the abutment portion 293 slides more smoothly between the first support portion 2921 and the second support portion 2922; at the same time, the shapes of the second support portion 2922 and the abutment portion 293 are adapted to each other, so that the abutment portion 293 and the second support portion 2922 can be better positioned when the pressure relief valve 280 stops releasing pressure, thereby reducing or avoiding the string movement between the two.

[0084] More preferably, in this embodiment, at least a portion of the first supporting portion 2921 is in a concave arc shape that is compatible with the abutting portion 293 .

[0085] With such a configuration, the abutting portion 293 can be positioned when abutting against the first supporting portion 2921 , thereby reducing or avoiding the abutting portion 293 from sliding off the first supporting portion 2921 during active pressure relief.

[0086] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Those skilled in the art should understand that the utility model includes but is not limited to the contents described in the drawings and the above specific implementation. Any modification that does not deviate from the functional and structural principles of the utility model will be included in the scope of the claims.

Claims

1. An airless portable spray gun, comprising a housing, a liquid pot, a nozzle, a pump body, a driving mechanism and a liquid outlet valve, wherein the nozzle is arranged at the front end of the housing, the pump body comprises a pump chamber, the liquid inlet end of the pump chamber is connected to the liquid pot through a first check valve, and the liquid outlet end of the pump chamber is connected to the liquid outlet valve through a second check valve, characterized in that: The liquid outlet valve includes a valve body with a buffer cavity and a valve seat, a valve head and a spring arranged in the valve body. The valve seat is provided with a liquid outlet hole connected to the nozzle. The spring acts on the valve head to make the valve head close the liquid outlet hole. The driving mechanism drives the pump body to extract liquid from the liquid pot and press it into the buffer cavity. The valve head opens after the pressure in the buffer cavity exceeds the preset liquid outlet pressure to make the liquid in the buffer cavity sprayed out from the nozzle through the liquid outlet hole.

2. An airless portable spray gun as claimed in claim 1, characterized in that: The valve seat includes a valve seat body and a tail seat, the tail seat is detachably fixedly connected to the valve seat body, the tail seat is installed at one end of the valve seat body away from the nozzle, a limiting cavity for limiting the valve head and the spring is formed between the tail seat and the valve seat body, and the valve head is movable in the limiting cavity.

3. An airless portable spray gun as claimed in claim 2, characterized in that: The tail seat is hollow to form a liquid inlet hole connected to the liquid outlet hole, and the valve head seals the liquid inlet hole to close the liquid outlet hole.

4. An airless portable spray gun as claimed in claim 2, characterized in that: The valve seat also includes a movable rod, which is slidably disposed in the valve seat body. The movable rod and the valve seat body are circumferentially sealed to form a sealed cavity between the movable rod and the tail seat. The spring is disposed in the sealed cavity, one end of the spring abuts against the tail seat, and the other end abuts against the movable rod. The valve head is fixed on the movable rod, and the valve head includes a conical head, and a portion of the head extends into the liquid outlet to close the liquid outlet.

5. An airless portable spray gun as claimed in claim 1, characterized in that: A fixing frame is provided at one end of the valve body close to the pump body, and the valve body also includes a movable rod. The valve head is fixed on the movable rod. A blind hole is provided on the fixing frame. One end of the movable rod can be movably extended into the blind hole. One end of the spring abuts against the fixing frame, and the other end abuts against the movable rod. The valve head includes a conical head, and part of the head extends into the liquid outlet to close the liquid outlet.

6. An airless portable spray gun as claimed in claim 1, characterized in that: The driving mechanism acts on the pump body to change the size of the pump chamber, and the ratio of the liquid volume of the pump chamber filled with liquid to the volume of the buffer chamber that can accommodate liquid is in the range of 1:1 to 1:

50.

7. An airless portable spray gun as claimed in claim 1, characterized in that: The pump body also includes a pressure relief channel, which includes a first channel connected to the pump chamber and a second channel connected to the liquid pot. A pressure relief valve is provided between the first channel and the second channel. The preset pressure relief pressure of the pressure relief valve is greater than the preset liquid outlet pressure of the valve body.

8. An airless portable spray gun as claimed in claim 7, characterized in that: The pressure relief valve includes a pressure relief valve housing, a pressure relief tail seat, a pressure relief valve stem, a pressure relief valve head and a pressure relief spring. The pressure relief valve housing is provided with a first pressure relief hole and a second pressure relief hole that are interconnected. The first pressure relief hole is communicated with the first channel, and the second pressure relief hole is communicated with the second channel. The pressure relief valve stem can be movably mounted on the pressure relief tail seat. One end of the pressure relief spring abuts against the pressure relief tail seat, and the other end abuts against the pressure relief valve stem. The pressure relief valve head is fixed on the pressure relief valve stem. A conical surface is formed on the pressure relief valve head. The spring acts on the pressure relief valve stem to press the conical surface against the first pressure relief hole. When the pressure in the buffer chamber is less than the preset pressure relief pressure, the pressure relief valve head and the pump chamber are sealed.

9. An airless portable spray gun as claimed in claim 8, characterized in that: The pressure relief valve also includes a pressure relief valve cover, the tail end of the pressure relief valve stem extends in a direction away from the pressure relief channel and passes through the pressure relief valve cover, and the tail end of the pressure relief valve stem is operably installed with a pressure relief component. The pressure relief component is operated to make the pressure relief valve head open the first pressure relief hole, so that the pressure relief valve actively relieves pressure.

10. An airless portable spray gun as claimed in claim 9, characterized in that: The pressure relief component includes a knob, and the knob covers the pressure relief valve cover and rotates relative to the pressure relief valve cover. A supporting portion is provided on one of the pressure relief valve cover and the knob, and an abutting portion is provided on the other. The pressure relief spring acts on the knob to make the abutting portion abut against the supporting portion. The supporting portion includes a first supporting portion and a second supporting portion. When the abutting portion abuts against the first supporting portion, the pressure relief valve actively relieves pressure, and when the abutting portion abuts against the second supporting portion, the pressure relief valve stops actively relieving pressure.

11. An airless portable spray gun as claimed in claim 10, characterized in that: The support portion further includes a spacing portion disposed between the first support portion and the second support portion, and a surface of the spacing portion gradually changes from the first support portion toward the second support portion.

12. An airless portable spray gun as claimed in claim 11, characterized in that: The abutting portion is in a convex arc shape, and the second supporting portion is in a concave arc shape adapted to the abutting portion.

13. An airless portable spray gun as claimed in claim 12, characterized in that: At least a portion of the first supporting portion is in a concave arc shape that is adapted to the abutting portion.

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