On / off valve device

Abstract

To provide a manual on-off valve device which is used in a jetting device that jets liquid containing powder and which prevents the use in the halfway opening state and prevents separation of a component of the liquid and clogging due to the powder in the liquid.SOLUTION: An on-off valve device 7 according to the present invention which is provided on the upstream side of a nozzle 3 in a jetting device 1 that jets liquid containing powder from the nozzle 3 by supplying the liquid to the nozzle 3 with the prescribed pressure and opens / closes a flow passage leading to the nozzle 3 comprises: a valve body 13 which has an operation part; a valve seat 15; biasing means which biases the valve body 13 in the closing direction; and an operation lever 19 which operates the operation part to push down the valve body 13 in the opening direction. The valve body 13 includes a pressure acting surface on which the pressure of the liquid acts when the valve body 13 is opened, and the pressure acting surface is configured such that the pressure of the liquid acts in the direction of opening the valve body when the pressure acts thereon.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an on-off valve device that opens and closes a flow path of a liquid in an injection device that injects a liquid containing powder.

Background Art

[0002] In fire extinguishing activities, a liquid to which a powdery additive is added may be injected onto a target object. Examples of such a liquid include, for example, the "light-shielding agent" disclosed in Patent Document 1. When a fire breaks out in a house equipped with a solar panel, if water is discharged for fire extinguishing, there is a risk of electric leakage or electric shock to fire extinguishers due to the electricity generated by the solar panel. Therefore, by applying a light-shielding agent such as that in Patent Document 1 to the surface of the solar panel, the light incident on the solar panel can be blocked. Such a light-shielding agent is composed of, for example, dispersing powdery additives such as swelling layered clay minerals and light-shielding pigments in water.

[0003] Another example of a liquid containing powder is the "flame spread inhibitor" disclosed in Patent Document 2. Old houses equipped with a thatched roof or other plant roof are at high risk of ignition and spread of fire from a neighboring fire by flying fire. Therefore, as a measure to prevent the spread of fire, it may be necessary to spray fire extinguishing water on such houses. However, the sprayed fire extinguishing water easily flows out from the plant roof, and it was necessary to continuously spray fire extinguishing water. Therefore, by using a flame spread inhibitor such as that in Patent Document 2, a high-viscosity flame spread inhibitor is retained on the plant roof, so a large amount of fire extinguishing water is not required and the spraying amount can be reduced. Such a flame spread inhibitor is also composed of dispersing inorganic powder in water in order to ensure the viscosity retained on the roof surface.

[0004] The liquid containing powder as described above is injected onto a target object using an injection device. Examples of the injection device include, for example, one that accommodates the above liquid in a backpack tank or the like and is carried by an operator, and supplies the liquid from the tank to a nozzle at a predetermined pressure and injects it. The injection device described above is equipped with an on-off valve device upstream of the nozzle for opening and closing the liquid flow path. Among the on-off valve devices, there are known manual on-off valve devices in which the flow path is opened and closed by an operator manually moving a lever. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-93288 [Patent Document 2] Japanese Patent Publication No. 2018-68672 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, when using a manual on-off valve device as described above in a spraying device that sprays a liquid containing powder, the following problems arose.

[0007] In a manually operated valve mechanism, the valve body is normally pressed against the valve seat by a spring, keeping the valve closed. However, by operating a lever, the operator compresses the spring, causing the valve body to separate from the seat and the valve to open. The valve opening angle increases with the angle the lever is moved. As the valve opening increases, the spring compresses further and the spring's repulsive force increases; therefore, the operator must gradually increase the force applied to the lever. Moving the lever all the way down results in a fully open valve, but if the operator stops applying force to the lever midway, the valve may operate in a partially open state.

[0008] However, if the valve continues to be used with a small gap between the valve body and the valve seat, there is a problem in that the powder in the liquid accumulates in the gap between the valve body and the valve seat, causing the components to separate. In addition, the accumulated powder can gradually clog the space between the valve body and the valve seat, causing the valve opening and closing device to malfunction.

[0009] The present invention has been made to solve the aforementioned problems, and aims to provide a manually operated on-off valve device used in an injection device that sprays a liquid containing powder, which prevents the valve from being used in an partially open state, and prevents the separation of liquid components and clogging by powder in the liquid. [Means for solving the problem]

[0010] (1) The on / off valve device according to the present invention is provided upstream of a nozzle in an injection device that supplies a liquid containing powder to a nozzle at a predetermined pressure and ejects it from the nozzle, and opens and closes the flow path to the nozzle, and comprises a valve body having an operating part, a valve seat, a biasing means for biasing the valve body in the closing direction, and an operating lever for operating the operating part to push down the valve body in the opening direction, wherein the valve body has a pressure acting surface on which the pressure of the liquid acts when the valve body is open, and the pressure acting surface is configured such that when the pressure of the liquid acts, the pressure acts in the direction that opens the valve body.

[0011] (2) Furthermore, in the present invention described in (1) above, the valve seat has an annular portion, the valve body has an insertion portion that can be inserted into the annular portion, the valve is closed when the insertion portion of the valve body is inserted into the annular portion of the valve seat and comes into contact with the inner circumferential surface of the annular portion, and the valve is open when the insertion portion and the annular portion do not come into contact.

[0012] (3) The device described in (1) or (2) above is characterized in that it has a cylinder member that guides a part of the valve body so that it can move forward and backward, the biasing means is housed in the cylinder member and the cylinder member is sealed so that the liquid does not enter it. [Effects of the Invention]

[0013] The valve body of the on-off valve device of the present invention has a pressure acting surface on which the pressure of the liquid acts when the valve body is open. The pressure acting surface is configured such that when the pressure of the liquid acts on the pressure acting surface, the pressure acts in the direction of opening the valve body. As a result, the force resisting valve operation is greatly reduced immediately after the valve opens. Furthermore, because the liquid pressure when the valve body opens acts in the direction of opening the valve body, the operating force required to fully open the valve can be made smaller than the operating force required at the start of valve opening. Therefore, the operator can squeeze the lever all the way to the fully open state with the same force applied to the lever just before the valve opens. Consequently, situations where the valve is partially open, as in the conventional case, are less likely to occur, thus preventing separation of liquid components and clogging by powder in the liquid. [Brief explanation of the drawing]

[0014] [Figure 1] This is an explanatory diagram (part 1) of an on / off valve device according to one embodiment of the present invention. [Figure 2] This is an explanatory diagram (part 2) of an on / off valve device according to one embodiment of the present invention. [Figure 3] This is a diagram illustrating the operation of the on-off valve device according to the embodiment (part 1). [Figure 4] This is a diagram illustrating the operation of the on / off valve device according to the embodiment (part 2). [Figure 5] This is a diagram illustrating the operation of the on-off valve device according to the embodiment (part 3). [Figure 6] This is a diagram illustrating a conventional on-off valve device (Part 1). [Figure 7] This is a diagram illustrating a conventional on-off valve device (part 2). [Figure 8] This is a diagram illustrating the operation of a conventional on-off valve device (Part 1). [Figure 9] This is a diagram (part 2) illustrating the operation of a conventional on-off valve device. [Figure 10] This is a diagram (part 3) illustrating the operation of a conventional on-off valve device. [Figure 11] This diagram illustrates the challenges of conventional on-off valve devices. [Modes for carrying out the invention]

[0015] Before describing an on-off valve device according to one embodiment of the present invention, we will first describe in detail the conventional manual on-off valve device and its problems. The conventional injection device 50, which was equipped with an on / off valve device 35, injects a liquid containing powder (hereinafter simply referred to as "liquid"), and as shown in the cross-sectional view of Figure 6, it has a tank (not shown) for storing the liquid, a nozzle 3 for discharging the liquid, a supply pipe 5 for supplying the liquid from the tank to the nozzle 3, and a pump (not shown) for sending the liquid from the tank to the supply pipe 5 at a predetermined pressure. Alternatively, the liquid from the tank may be sent to the supply pipe 5 by gas pressure instead of the pump.

[0016] The conventional on / off valve device 35 is provided inside the supply pipe 5 and includes a valve body 39 consisting of a shaft portion 9 and a main body portion 37, a valve seat 41, a biasing spring 17 that biases the valve body 39 in the closing direction, and an operating lever 19 provided outside the supply pipe 5 that operates the shaft portion 9 to push down the valve body 39 in the opening direction. The shaft portion 9 consists of a protruding portion 9a that penetrates the pipe wall of the supply pipe 5 and protrudes to the outside of the supply pipe 5, and a smaller diameter portion 9b that is located inside the supply pipe 5 and has a smaller diameter than the protruding portion 9a. An O-ring 21 is fitted around the outer circumference of the protruding portion 9a, sealing the portion that penetrates the supply pipe 5 so that it can move up and down.

[0017] Furthermore, an O-ring 43 is fitted around the outer circumference of the main body 37 of the valve body 39. Under normal conditions, the biasing spring 17 presses the main body 37 against the valve seat 41, causing the O-ring 43 to tightly adhere to the valve seat 41 and keeping the valve closed (see Figure 7(a)).

[0018] In use, the operator holds the supply pipe 5 and grasps the operation lever 19 with the hand holding the supply pipe 5, and tilts it from the "closed position" to the "fully open position" in FIG. 6 to open the valve. Specifically, by tilting the operation lever 19, the convex portion 19a provided on the operation lever 19 presses downward on the upper end of the shaft portion 9 (protruding portion 9a) protruding from the pipe wall of the supply pipe 5, and presses down the valve body 39 against the biasing force of the biasing spring 17. Since liquid is supplied to the primary side of the valve at a predetermined pressure by a pump, when the valve body 39 moves and a gap is formed between the valve body 39 and the valve seat 41, the liquid on the primary side of the valve flows into the secondary side of the valve through this gap. The liquid flowing into the secondary side of the valve is supplied to the nozzle 3 by the water supply pressure of the pump and is ejected from the nozzle 3.

[0019] As described above, the conventional on-off valve device 35 opens the valve when the operator grasps the operation lever 19 (tilts it from the "closed position" to the "fully open position" in FIG. 6). At this time, the force applied by the operator to the operation lever 19, that is, the force required to press down the valve body 39, will be described in detail below based on FIGS. 8 to 10. FIG. 8(a) shows the state of the on-off valve device 35 when the valve is closed. At this time, two forces F 1S and F 1P acting in the valve closing direction are applied to the valve body 39 as shown by the arrows in the figure. The force F 1S is the biasing force of the biasing spring 17, and this biasing force F 1S increases according to the amount of compression of the biasing spring 17. Therefore, regarding the biasing force F 1S , the biasing force during normal times (when the valve is closed) is particularly denoted as F 1S(min) , and the biasing force when the biasing spring is most compressed (when the valve is fully open) is particularly denoted as F 1S(max) . The force F 1P is the force generated when the pressure of the liquid 34 filling the primary side of the valve acts on the lower surface of the valve body. The force F 1P due to the pressure of the liquid 34 will be described in detail later.

[0020] The forces F 1S and F 1P acting in the above valve closing directionIn order to push down the valve body 39 against the force, F 1S +F 1P The above force must be applied to the shaft portion 9. Therefore, the operator applies the force F to the shaft portion 9 by gradually increasing the force with which they grip the operating lever 19, as shown in Figure 8(b). o To increase.

[0021] F o >F 1S +F 1P As a result, as shown in Figure 9(a), the force F o This pushes down the shaft portion 9, causing the valve body 39 to descend. As the valve body 39 descends, the O-ring 43, which was in close contact with the valve seat 41, separates from the valve seat 41, and the primary side of the valve and the secondary side of the valve come into communication. When the primary and secondary sides of the valve are in communication and liquid 34 flows into the secondary side, the primary and secondary sides of the valve become equal in pressure, and a force F in the valve closing direction is exerted by the pressure of the liquid 34. 1P It stops working. On the other hand, the liquid 34 that flows into the secondary side of the valve creates a new force F in the direction of valve closing. 2P This occurs. Specifically, the liquid 34 filling the secondary side of the valve exerts pressure on the lower surface of the protruding portion 9a, creating a force F in the upward direction, i.e., in the valve closing direction. 2P It works.

[0022] Force F in the valve closing direction due to the pressure of liquid 34 1P and F 2P The force F increases in proportion to the size (outer diameter) of the surface on which the pressure of the liquid 34 acts. The size of the surface on which the surface is acted increases in proportion to the cross-sectional area of ​​the part where the surface is provided (specifically, the cross-sectional area of ​​the part separating the atmospheric pressure area from the part filled with liquid 34). That is, the force F acting on the lower surface of the main body 37 of the valve body 39 as the surface on which the force F acts. 1P The size of the force F is proportional to the cross-sectional area of ​​the portion of the main body 37 shown by the dashed circle in Figure 8(a), and acts with the lower surface of the protrusion 9a as the surface of action. 2P The size of the projection 9a corresponds to the cross-sectional area of ​​the portion shown by the dashed circle in Figure 9(a).

[0023] In this example, the cross-sectional area of ​​the portion shown by the dashed circle in Figure 9(a) is smaller than the cross-sectional area of ​​the portion shown by the dashed circle in Figure 8(a), therefore F 1P >F 2P This is the result. Therefore, the force acting in the direction of valve closure is (F) when the valve is closed. 1S(min) +F 1P ) is better than immediately after valve opening (F 1S(min) +F 2P As the force required to push down the valve body 39 becomes smaller, the force required to push down the valve body 39 temporarily decreases immediately after the valve opens, as shown in Figure 9(b). Strictly speaking, the biasing spring 17 is more compressed immediately after the valve opens than when the valve is closed, so the biasing force is F. 1S(min) It will be larger than that, but the increase is small, so we will ignore it here.

[0024] As described above, the force acting in the valve closing direction temporarily decreases immediately after the valve opens, but as the valve opening degree increases thereafter, the biasing spring 17 compresses and the biasing force F increases. 1S As this increases, the force acting in the valve closing direction also increases. Specifically, the force acting in the valve closing direction is the force F shown in Figure 9(a) immediately after valve opening. 1S(min) +F 2P From Figure 10(a), the force F when the valve is fully open. 1S(max) +F 2P The force gradually increases until the operator gradually increases the force with which they grip the operating lever 19, as shown in Figure 10(b), thereby applying force F to the shaft 9. o Operate the control lever 19 to increase the valve. When the control lever 19 is pushed to its maximum position, the valve is fully open and the valve opening operation is completed.

[0025] As described above, in conventional on-off valve devices 35, the valve opening degree increases as the operator gradually increases the force with which they grip the operating lever 19 after the valve has been opened. Therefore, it is easy to hold the operating lever 19 in a partially open state depending on the force applied by the operator. For example, if the operating lever 19 is held while the valve is still partially open immediately after it has been opened and water is being discharged, the powder dispersed in the liquid 34 is likely to accumulate between the valve body 39 and the valve seat 41, which can cause a blockage 45 due to the powder as shown in Figure 11. This blockage 45 due to the powder in the liquid 34 is problematic because it can cause the separation of components in the liquid 34 and malfunction of the on-off valve device 35, as described above.

[0026] Therefore, in the on / off valve device according to this embodiment, the injection device 1 is prevented from being used in an partially open state, thereby preventing clogging 45 by powder in the liquid 34 as described above. A detailed explanation will follow below with reference to Figures 1 and 2. Figure 1 is a cross-sectional view showing a part of the injection device 1 in which an on-off valve device is provided, and Figures 2(a) and 2(b) are enlarged partial views showing the closed and fully open states of the on-off valve device. In Figures 1 and 2, the same reference numerals are used for parts that are the same as or corresponding to those in Figures 6 and 7 which describe the conventional example.

[0027] The on-off valve device 7 of this embodiment, similar to the conventional example, is installed upstream of the nozzle 3 in the injection device 1 that supplies a liquid containing powder to the nozzle 3 at a predetermined pressure and sprays it from the nozzle 3, and opens and closes the flow path leading to the nozzle 3. As shown in Figure 1, the on / off valve device 7 includes a valve body 13 having a shaft portion 9, a valve seat 15, a cylinder member 16 that guides a part of the valve body 13 so that it can move back and forth, a biasing spring 17 that biases the valve body 13 in the closing direction, and an operating lever 19 that operates the shaft portion 9 to push down the valve body 13 in the opening direction. Each component will be described in detail below.

[0028] <valve body> The valve body 13 normally contacts the valve seat 15 to close the liquid flow path, and consists of a shaft portion 9, which corresponds to the operating part of the present invention, and a main body portion 11. The shaft portion 9, as in the conventional example, has a protruding portion 9a that penetrates the pipe wall of the supply pipe 5 and protrudes to the outside of the supply pipe 5, and a small-diameter portion 9b that has a smaller diameter than the protruding portion 9a. The main body 11 has an insertion portion 23 that can be inserted into the annular portion 15a of the valve seat 15, which will be described later, and an O-ring 25 is fitted around the outer circumference of the insertion portion 23. When the insertion portion 23 is inserted into the annular portion 15a of the valve seat 15, the outer circumference of the O-ring 25 comes into contact with the inner surface of the annular portion 15a, and the liquid flow path is closed. When the insertion portion 23 is removed from the annular portion 15a of the valve seat 15 and the annular portion 15a and the O-ring 25 are separated (no longer in contact), the liquid flow path is opened.

[0029] Furthermore, the lower part of the main body 11 is housed in the cylinder member 16 so as to be able to move back and forth. An O-ring 27 is also fitted around the outer circumference of the part housed in the cylinder member 16. The O-ring 27 fitted to the lower part of the main body 11 is always in contact with the inner surface of the cylinder member 16, sealing it to prevent liquid from entering the cylinder member 16.

[0030] Furthermore, the valve body 13 has a pressure acting surface on which the liquid pressure acts when the valve body 13 is open. In this embodiment, the pressure acting surface consists of two acting surfaces: a first pressure acting surface 29 which is the lower surface of the protrusion 9a and a second pressure acting surface 31 which is the upper surface of the main body 11. In order to ensure that when liquid pressure acts on the two surfaces mentioned above, the pressure acts in a direction that opens the valve body 13, the protrusion 9a is formed to have a smaller diameter than the main body 11. The reason for this will be explained in detail in the operation description below.

[0031] <Valve seat> The valve seat 15 normally contacts the main body 11 of the valve body 13 to close the flow path of liquid, and has an annular portion 15a into which the insertion portion 23 of the main body 11 can be inserted. In this embodiment, as shown in Figure 2(a), the valve is closed when the O-ring 25 provided in the insertion portion 23 of the main body 11 comes into contact with the inner circumferential surface of the annular portion 15a of the valve seat 15. Compared to the conventional example shown in Figure 7(a), where the valve is closed when the corner of the valve seat 41 comes into contact with the O-ring 43 of the valve body 39, the biasing force required to maintain the seated state of the valve body 13 can be reduced. Reducing the biasing force required to maintain the valve closed state enhances the effects of the present invention, which will be explained in detail in the operation description below.

[0032] <Cylinder component> The cylinder member 16 guides a portion of the valve body 13 (specifically, the lower part of the main body 11) so that it can move back and forth. A biasing spring 17 is housed inside the cylinder member 16. As mentioned above, the O-ring 27 provided at the lower part of the main body 11 is always in contact with the inner circumferential surface of the cylinder member 16, so no liquid enters the part of the cylinder member 16 where the biasing spring 17 is housed. Therefore, the internal pressure of the cylinder member 16 is approximately atmospheric pressure.

[0033] <Bounce spring> The biasing spring 17 corresponds to the biasing means of the present invention and biases the valve body 13 in the closing direction. The biasing spring 17 is the same as in the conventional example, so its description is omitted. As mentioned above, in this embodiment, the biasing force required to maintain the valve closed state is smaller than in the conventional example, so the biasing force F of the biasing spring 17 in this embodiment 1S(min) The biasing force F of the biasing spring 17 in the conventional example. 1S(min) It should be smaller than [this value].

[0034] <Operating lever> The operating lever 19 operates the shaft portion 9 of the valve body 13 to push the valve body 13 downward in the opening direction, and under normal circumstances it is in the "closed position" as shown in Figure 1. When the operator grasps the operating lever 19 together with the supply pipe 5 with the hand that is holding the supply pipe 5, the operating lever 19 rotates towards the "fully open position" around the operating lever axis 33. As the operating lever 19 is rotated, the protrusion 19a on the operating lever 19 presses downward against the upper end of the shaft portion 9, pushing down the valve body 13 and opening the liquid flow path (see Figure 2(b)).

[0035] Next, the operation of the on-off valve device 7 when manually opening the on-off valve device 7 of this embodiment, and the force required to push down the valve body 13 at that time, will be described in detail below. Figure 3(a) shows the state of the on / off valve device 7 when the valve is closed. At this time, the valve body 13 is subjected to the biasing force F of the biasing spring 17 acting in the valve closing direction, as indicated by the arrow in the figure. 1S(min) It has been added.

[0036] In the conventional example shown in Figure 8(a), the biasing force F of the biasing spring 17 1S(min) In addition, there is a force F in the valve closing direction due to the pressure of the liquid 34. 1P Although it was working, in this embodiment, since the lower surface of the main body portion 11 of the valve body 13 is housed in the cylinder member 16, the pressure of the liquid 34 does not act on the lower surface of the main body portion 11, and force F 1P This does not occur. Therefore, when the valve is closed, the force acting in the direction of valve closure is the biasing force F of the biasing spring 17. 1S(min) Therefore, as shown in Figure 3(b), the operator gradually increases the force with which they grip the operating lever 19, thereby applying force F to the shaft portion 9. o F 1S(min) Increase it so that it exceeds the above amount.

[0037] F o >F 1S(min) As a result, as shown in Figure 4(a), the force F o This pushes down the shaft portion 9, causing the valve body 13 to descend. As the valve body 13 descends, the insertion portion 23 disengages from the annular portion 15a of the valve seat 15, and the O-ring 25 of the insertion portion 23 separates from the valve seat 15, creating communication between the primary and secondary sides of the valve. When the primary and secondary sides of the valve are in communication and liquid 34 flows into the secondary side of the valve, the pressure of the liquid 34 filling the secondary side of the valve acts on the first pressure surface 29 and the second pressure surface 31 of the valve body 13.

[0038] First, when the pressure of the liquid 34 acts on the first pressure acting surface 29, which is the lower surface of the protrusion 9a, a force F in the valve closing direction is exerted, similar to the conventional example. 2P It works. Then, when the pressure of the liquid 34 acts on the second pressure acting surface 31, which is the upper surface of the main body 11, a force F is exerted in the downward direction, i.e., in the valve opening direction. 3P It works.

[0039] In the conventional example shown in Figure 9(a), a force F in the valve opening direction did not occur. 3P However, the reasons for this in this embodiment are as follows. First, there is the force F in the valve closing direction due to the pressure of the liquid 34 mentioned above. 1P and F 2P Both of these phenomena occur due to a pressure difference in the space separated by the O-rings 43 and 21 fitted to the valve body 13. For example, in the conventional valve closed state shown in Figure 8(a), with respect to the primary and secondary sides of the valve separated by the O-ring 43, the internal pressure on the primary side of the valve is the pressure of the liquid 34 (pump pressure), while the internal pressure on the secondary side of the valve is atmospheric pressure. Therefore, when the pressure of the liquid 34 acts on the lower surface of the main body 37, the pressure on the upper side of the main body 37 is small, resulting in an upward pressing force, and a force F in the valve closing direction. 1p This is the result. Furthermore, as in the conventional example in Figure 9(a) or the embodiment in Figure 4(a), in the valve open state, regarding the pressure inside and outside the supply pipe 5 separated by the O-ring 21 fitted to the protrusion 9a, the internal pressure of the supply pipe 5 is the pressure of the liquid 34 (pump pressure), while the external pressure of the supply pipe 5 is atmospheric pressure. Therefore, when the pressure of the liquid 34 acts on the lower surface (first pressure acting surface) of the protrusion 9a, an upward pressing force is generated because the pressure on the upper side of the protrusion 9a is small, resulting in a force F in the valve closing direction. 2p This is the result.

[0040] Similarly, in this embodiment shown in Figure 4, with respect to the internal space between the supply pipe 5 and the cylinder member 16 separated by an O-ring 27 fitted to the lower part of the main body 27, the internal pressure of the supply pipe 5 is the pressure of the liquid 34 (pump pressure), while the internal pressure of the cylinder member 16 is atmospheric pressure. Therefore, when the liquid 34 flows into the secondary side of the valve and the pressure of the liquid 34 acts on the upper surface (second pressure acting surface) of the main body 11, a downward pressing force is generated because the pressure on the lower side of the main body 11 is small, resulting in a force F in the valve opening direction. 3p And that's how it is.

[0041] Thus, when the valve opens and liquid 34 flows into the secondary side of the valve, the pressure of the liquid 34 acts on the first pressure surface 29 and the second pressure surface 31, resulting in two opposing forces F. 2p F 3p Although this occurs, in this embodiment, the force F in the valve opening direction 3p The first pressure surface 29 and the second pressure surface 31 are configured such that the latter is larger, and this point will be explained. As mentioned above, the force due to the pressure of the liquid 34 increases in proportion to the size (outer diameter) of the surface on which the pressure of the liquid 34 acts. And the size of the surface on which the pressure acts increases in proportion to the cross-sectional area of ​​the part on which the surface on which the pressure is provided.

[0042] As mentioned above, the protrusion 9a on which the first pressure surface 29 is provided is formed to have a smaller diameter than the main body portion 11 on which the second pressure surface 31 is provided. Therefore, the force F acting on the first pressure surface 29 2P This is the force F acting on the second pressure surface 31. 3P It will become smaller. Therefore, immediately after the valve opens, there are two opposing forces F 2p F 3p However, F 2P <F 3P Therefore, the force in the direction of valve closing immediately after valve opening (F 1S(min) +F 2P -F 3P ) is the force (F) in the direction of valve closure when the valve is closed. 1S(min) It becomes smaller than ).

[0043] Furthermore, as mentioned above, in this embodiment, the biasing force F of the biasing spring 17 when the valve is closed 1S(min) However, this is smaller than in conventional examples. The biasing force F of the biasing spring 17. 1S(min) If this value is small, the effect of reducing the force in the valve closing direction, as described above, becomes relatively larger. Therefore, the operator can open the valve with less force than in conventional examples, and furthermore, immediately after opening the valve, the force resisting the operation of the operating lever 19 is perceived to be significantly reduced (see Figure 4(b)).

[0044] After the valve opens, as in the conventional example, the biasing spring 17 compresses as the valve opening increases, and the biasing force F 1S As this increases, the force F required to push down the valve body 13 o This also increases. However, in this embodiment, the force in the valve opening direction due to the pressure of the liquid 34 (=F 3P -F 2P ) is the increment of the biasing force of the biasing spring 17 (=F 1S(max) -F 1S(min) Since it is configured to be larger than the force applied just before valve opening, the valve can be fully opened without increasing the operating force (see Figures 5(a) and 5(b)).

[0045] As described above, according to this embodiment, the pressure acting surface is configured such that when the valve body 13 is opened, the liquid pressure acts in the direction that opens the valve body 13. As a result, the force resisting valve operation is greatly reduced immediately after the valve opens. Furthermore, the force required to fully open the valve is less than the force required to open the valve. Therefore, when the operator operates the valve opening / closing device 7, they can squeeze the lever to its maximum extent using only the force required to open the valve. This makes it less likely that the operator will interrupt the operation and continue using the device in a partially open state, as has happened in the past, thus preventing the separation of liquid components and clogging by powder in the liquid.

[0046] In this embodiment, the valve is closed when the insertion portion 23 of the valve body 13 is inserted into the annular portion 15a of the valve seat 15 and the O-ring 25 of the insertion portion 23 comes into contact with the inner circumferential surface of the annular portion 15a. However, the present invention is not limited to this, and for example, as in the conventional example, the valve may be closed when the O-ring 43 of the valve body 39 comes into contact with the corner of the valve seat 41. However, this embodiment is preferable because it allows the biasing force of the biasing spring 17 to be reduced, and the valve can be opened with little force, making it less likely that the valve will be used in a state where the valve opening is extremely small.

[0047] Furthermore, this embodiment is configured such that the operating force required to fully open the valve is less than the operating force required to open the valve, but the present invention is not limited to this. This invention was conceived to prevent the valve from being used with an extremely small opening. If the liquid pressure acts in a direction that opens the valve body, the situation in which the valve is used with an extremely small opening becomes less likely, and therefore this invention is effective. However, this embodiment is more preferable because it allows the valve to be fully opened without increasing the force applied when opening the valve, thus stabilizing the valve opening. [Explanation of symbols]

[0048] 1 Injector 3 nozzles 5 Supply pipe 7. On / off valve device 9. Shaft section 9a Protrusion 9b Small diameter section 11 Main body 13 Valve body 15 valve seats 15a Annular section 16 Cylinder Member 17. Biasing spring 19. Operating lever 19a Convex part 21 O-ring (protruding part) 23 Insertion part 25 O-ring (insertion part) 27 O-ring (main body) 29 First pressure acting surface 31 Second pressure acting surface 33 Operating lever shaft 34 (Liquid containing powder) 35. On / off valve device (conventional example) 37 Main body (conventional example) 39 Valve body (conventional example) 41. Valve seat (conventional example) 43 O-ring (conventional example) 45. Blockage 50 Injection device (conventional example)

Claims

[Claim 1] A spraying device that supplies a liquid containing powder to a nozzle at a predetermined pressure and sprays it from the nozzle, The nozzle has a valve body provided on the upstream side for opening and closing the flow path, and an operating lever for pushing the valve body downward in the opening direction. The valve body is configured such that when it opens, the pressure of the liquid acts in a direction that opens the valve body. The valve body has a cylinder member that guides a portion of the valve body so that it can move forward and backward, and a biasing means housed within the cylinder member that biases the valve body in the closing direction. An injection device characterized in that the cylinder member is sealed to prevent the liquid from entering, so that when the valve body is closed, the pressure of the liquid does not act in the direction of closing the valve body.

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