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 for opening and closing a flow path for a liquid in an injection device that injects a liquid containing powder. [Background technology]

[0002] In firefighting activities, a liquid containing a powdered additive may be sprayed onto a target. An example of such a liquid is the "light blocking agent" disclosed in Patent Document 1. If a fire breaks out in a house equipped with solar panels, spraying water to extinguish the fire poses a risk of short circuits and electric shock to firefighters due to the electricity generated by the solar panels. Therefore, it is possible to block light incident on a solar panel by applying a light-blocking agent to the surface of the solar panel as described in Patent Document 1. Such a light-blocking agent is composed of, for example, powdered additives such as swellable layered clay minerals and light-blocking pigments dispersed in water.

[0003] Another example of a liquid containing a powder is the "fire prevention agent" disclosed in Patent Document 2. Old houses and other buildings with thatched or other vegetative roofs are at high risk of ignition and fire spread due to sparks flying from nearby fires. Therefore, fire extinguishing water is sometimes sprayed on such houses as a fire prevention measure, but sprayed water tends to run off easily on vegetative roofs, making it necessary to spray water continuously. Therefore, by using a fire prevention agent such as that described in Patent Document 2, a highly viscous fire prevention agent is retained on the vegetative roof, eliminating the need for large amounts of fire extinguishing water and reducing the amount of water sprayed. Such fire prevention agents are also composed of inorganic powder dispersed in water to ensure the viscosity is retained on the roof surface.

[0004] The liquid containing the powder described above is sprayed onto a target object using a spraying device, such as a device in which the liquid is stored in a backpack-like container carried by an operator, and the liquid is supplied from the container to a nozzle at a predetermined pressure and sprayed. In the injection device as described above, an on-off valve device for opening and closing the liquid flow path is provided upstream of the nozzle. Known on-off valve devices include, for example, manual on-off valve devices in which an operator opens and closes the flow path by manually operating a lever. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-93288 [Patent Document 2] Japanese Patent Application Publication No. 2018-68672 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in an injection device for injecting a liquid containing powder, when the above-mentioned manual on-off valve device is used, the following problems arise.

[0007] In a manual on-off valve device, the valve disc is normally pressed against the valve seat by a spring, keeping the valve closed. When the operator operates the lever, the spring is compressed, and as the spring compresses, the valve disc moves away from the valve seat, opening the valve. The valve opening increases depending on the angle at which the lever is tilted, but the greater the valve opening, the more the spring compresses and the greater the spring's repulsive force, so the operator must operate the lever while gradually increasing the operating force applied to it. The valve is fully open when the lever is tilted to its maximum, but it may also be used in a partially open state if the operator stops applying force to the lever halfway.

[0008] However, if the valve continues to be used with a small gap between the valve disc and the valve seat, powder in the liquid can accumulate in the gap between the valve disc and the valve seat, causing the components to separate.Furthermore, the accumulated powder can gradually clog the gap between the valve disc and the valve seat, causing the on-off valve device to malfunction.

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

[0010] (1) The on-off valve device of 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 injects it from the nozzle, and opens and closes a flow path leading to the nozzle. It comprises a valve body having an operating part, a valve seat, a biasing means that biases the valve body in a closing direction, and an operating lever that operates the operating part to press down the valve body in an opening direction, and is characterized in that the valve body has a pressure acting surface on which the pressure of the liquid acts when the valve body is opened, and the pressure acting surface is configured so that when the pressure of the liquid acts, the pressure acts in a direction that opens the valve body.

[0011] (2) Furthermore, in the above (1), the valve seat has a circular ring portion, the valve body has an insertion portion that can be inserted into the circular ring portion, and the insertion portion of the valve body is inserted into the circular ring portion of the valve seat and abuts against the inner surface of the circular ring portion to enter a valve closed state, and the valve is opened when the insertion portion and the circular ring portion do not abut.

[0012] (3) Furthermore, in the device described in (1) or (2) above, a cylinder member is provided to guide a part of the valve body so that it can move back and forth, and the biasing means is housed within the cylinder member, and the cylinder member is sealed to prevent the liquid from entering. [Effects of the Invention]

[0013] The valve element of the on-off valve device of the present invention has a pressure application surface on which the pressure of the liquid acts when the valve element opens, and the pressure application surface is configured so that when the pressure of the liquid acts on the pressure application surface, the pressure acts in the direction of opening the valve element, thereby significantly reducing the force resisting valve operation immediately after the valve opens. Furthermore, by configuring the pressure of the liquid when the valve element opens to act in the direction of opening the valve element, the operating force required to fully open the valve can be made smaller than the operating force required to start opening the valve, so the operator can grip the lever to the fully open state while maintaining the same force applied to the lever just before the valve opened. Therefore, since the situation of the valve opening being partially opened as in the conventional technology is less likely to occur, separation of liquid components and clogging due to powder in the liquid can be prevented. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is an explanatory diagram (part 1) of an on-off valve device according to an embodiment of the present invention. [Figure 2] FIG. 2 is an explanatory diagram (part 2) of an on-off valve device according to an embodiment of the present invention. [Figure 3] 1A and 1B are diagrams for explaining the operation of the on-off valve device according to the embodiment (part 1). [Figure 4] 6A and 6B are diagrams for explaining the operation of the on-off valve device according to the embodiment (part 2). [Figure 5] 10A and 10B are diagrams illustrating the operation of the on-off valve device according to the embodiment (part 3). [Figure 6] FIG. 1 is an explanatory diagram of a conventional on-off valve device (part 1). [Figure 7] FIG. 2 is an explanatory diagram of a conventional on-off valve device (part 2). [Figure 8] FIG. 1 is a diagram for explaining the operation of a conventional on-off valve device (part 1). [Figure 9] FIG. 10 is a diagram illustrating the operation of a conventional on-off valve device (part 2). [Figure 10] FIG. 10 is a diagram for explaining the operation of a conventional on-off valve device (part 3). [Figure 11] 1A and 1B are diagrams illustrating problems with a conventional on-off valve device. DETAILED DESCRIPTION OF THE INVENTION

[0015] Before describing an on-off valve device according to an embodiment of the present invention, a conventional manual on-off valve device and its problems will be described in detail. 6, the spraying device 50 equipped with the conventional on-off valve device 35 sprays a liquid containing powder (hereinafter simply referred to as "liquid"), and has a tank (not shown) for storing the liquid, a nozzle 3 for discharging the liquid, a supply pipe 5 for supplying the liquid in the tank to the nozzle 3, and a pump (not shown) for feeding the liquid from the tank to the supply pipe 5 at a predetermined pressure. Note that the liquid in the tank may be fed to the water feed pipe 5 by gas pressure instead of the pump.

[0016] The conventional on-off valve device 35 includes a valve body 39 arranged inside the supply pipe 5 and 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 arranged outside the supply pipe 5 that operates the shaft portion 9 to push the valve body 39 down in the opening direction. Shaft portion 9 is composed of protruding portion 9a that penetrates the wall of supply pipe 5 and protrudes to the outside of supply pipe 5, and small diameter portion 9b that is disposed inside supply pipe 5 and has a smaller diameter than protruding portion 9a. An O-ring 21 is fitted around the outer periphery of protruding portion 9a, sealing the portion that penetrates supply pipe 5 so that it can move up and down.

[0017] In addition, an O-ring 43 is fitted around the outer periphery of the main body 37 of the valve element 39, and under normal circumstances, the main body 37 is pressed against the valve seat 41 by the biasing spring 17, causing the O-ring 43 to adhere tightly to the valve seat 41, and the valve is in a closed state (see Figure 7(a)).

[0018] During use, the operator grips operating lever 19 with the hand holding supply pipe 5 and tilts it from the "closed position" to the "fully open position" in Figure 6 to open the valve. Specifically, by tilting operating lever 19, convex portion 19a on operating lever 19 presses downward the upper end of shaft portion 9 (protruding portion 9a) that protrudes from the wall of supply pipe 5, pushing valve element 39 down against the biasing force of biasing spring 17. Because liquid is supplied to the primary side of the valve by the pump at a predetermined pressure, when valve element 39 moves and a gap is created between valve element 39 and valve seat 41, the liquid on the primary side of the valve flows through this gap into the secondary side of the valve. The liquid that has flowed into the secondary side of the valve is supplied to the nozzle 3 by the water supply pressure of the pump and is sprayed from the nozzle 3.

[0019] As described above, the conventional on-off valve device 35 opens the valve when the operator grips the operating lever 19 (pushing it from the "closed position" to the "fully open position" in Figure 6). The force that the operator applies to the operating lever 19 at this time, i.e., the force required to press down the valve body 39, will be described in detail below with reference to Figures 8 to 10. 8(a) shows the state of the on-off valve device 35 when the valve is closed. At this time, two forces F act on the valve element 39 in the valve closing direction, as shown by the arrows in the figure. 1S and F 1P has been added. force F 1S is the biasing force of the biasing spring 17, and this biasing force F 1S The biasing force F increases in accordance with the compression amount of the biasing spring 17. 1S Regarding the normal (valve closed) biasing force, especially F 1S(min) The force when the spring is most compressed (when the valve is fully open) is expressed as F 1S(max) It is written as follows. force F 1P is the force generated by the pressure of the liquid 34 filling the primary side of the valve acting on the underside of the valve body. 1P This will be explained in detail later.

[0020] The force F acting in the valve closing direction 1S , F 1PIn order to push down the valve body 39 against the 1S +F 1P The force F 100 must be applied to the shaft 9. Therefore, as shown in FIG. 8(b), the operator gradually increases the force with which he grips the operating lever 19 to apply the force F 100 to the shaft 9. o Increase.

[0021] F o >F 1S +F 1P As shown in Figure 9(a), the force F o The shaft portion 9 is pushed down by the pressure, and the valve element 39 descends. When the valve element 39 descends, the O-ring 43 that had been in close contact with the valve seat 41 separates from the valve seat 41, and the primary side of the valve communicates with the secondary side of the valve. When the primary side and secondary side of the valve communicate and the liquid 34 flows into the secondary side of the valve, the pressure on the primary side and the secondary side of the valve becomes the same, so the force F in the valve closing direction due to the pressure of the liquid 34 is 1P will no longer work. On the other hand, the liquid 34 flowing into the secondary side of the valve generates a new force F in the valve closing direction. 2P Specifically, the pressure of the liquid 34 that fills the secondary side of the valve acts on the lower surface of the protruding portion 9a, and a force F is generated in the upward direction, i.e., in the valve closing direction. 2P works.

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

[0023] In this example, the cross-sectional area of the portion shown in the dashed circle in FIG. 9(a) is smaller than the cross-sectional area of the portion shown in the dashed circle in FIG. 8(a), so F 1P >F 2P This becomes: Therefore, the force acting in the valve closing direction is 1S(min) +F 1P ) immediately after the valve is opened (F 1S(min) +F 2P ) becomes smaller, and as shown in FIG. 9(b), the force required to press down the valve element 39 temporarily decreases immediately after the valve is opened. Strictly speaking, the biasing spring 17 is compressed immediately after the valve is opened compared to when the valve is closed, so the biasing force is F 1S(min) However, this increase is so small that it is ignored here.

[0024] As described above, the force acting in the valve closing direction temporarily decreases immediately after the valve is opened, but as the valve opening degree increases, the biasing spring 17 contracts and the biasing force F 1S As the force acting in the valve closing direction increases, the force acting in the valve closing direction also increases. Specifically, the force acting in the valve closing direction is the force F immediately after the valve is opened in Figure 9(a). 1S(min) +F 2P From Fig. 10(a), the force F when the valve is fully open is 1S(max) +F 2P Therefore, as shown in FIG. 10(b), the operator gradually increases the force with which he grips the operating lever 19, and the force F applied to the shaft portion 9 o When the operating lever 19 is pushed to the maximum, the valve is fully open and the valve opening operation is completed.

[0025] As described above, in the conventional on-off valve device 35, the valve opening increases as the operator gradually increases the force with which they grip the operating lever 19 after the valve is opened. Therefore, depending on the amount of force applied by the operator, it is easy to hold the operating lever 19 in a partially open position. For example, if the operating lever 19 is held and water is continued to be discharged while the valve is still in a small opening position immediately after opening, powder dispersed in the liquid 34 tends to accumulate between the valve disc 39 and the valve seat 41, which can cause a powder clog 45 as shown in Figure 11. The powder clog 45 in the liquid 34 is problematic because it can cause the components of the liquid 34 to separate and the on-off valve device 35 to malfunction, as described above.

[0026] Therefore, the on-off valve device according to this embodiment is designed to prevent the injection device 1 from being used in a partially open state, and to prevent clogging 45 caused by powder in the liquid 34 as described above. Hereinafter, this will be described in detail with reference to Figs. 1 and 2. Fig. 1 is a cross-sectional view showing a part of an injection device 1 provided with an on-off valve device, and Fig. 2(a) and Fig. 2(b) are enlarged partial views showing the on-off valve device in a closed state and a fully open state. In Fig. 1 and Fig. 2, parts that are the same as or correspond to those in Fig. 6 and Fig. 7, which explain the conventional example, are given the same reference numerals.

[0027] The on-off valve device 7 of this embodiment, like the conventional example, is provided 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 injects it from the nozzle 3, and opens and closes the flow path leading to the nozzle 3. 1, the on-off valve device 7 includes a valve element 13 having a shaft portion 9, a valve seat 15, a cylinder member 16 that guides a portion of the valve element 13 so that it can move back and forth, a biasing spring 17 that biases the valve element 13 in the closing direction, and an operating lever 19 that operates the shaft portion 9 to push the valve element 13 down in the opening direction. Each component will be described in detail below.

[0028] <Valve body> The valve element 13 normally abuts against a valve seat 15 to close the liquid flow path, and is composed of a shaft portion 9, which corresponds to the operating portion of the present invention, and a main body portion 11. As in the conventional example, the shaft portion 9 has a protruding portion 9a that penetrates the 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 part 23 that can be inserted into the annular part 15a of the valve seat 15, which will be described later, and an O-ring 25 is fitted around the outer periphery of the insertion part 23. When the insertion part 23 is inserted into the annular part 15a of the valve seat 15, the outer periphery of the O-ring 25 abuts against the inner circumferential surface of the annular part 15a, closing the liquid flow path. When the insertion part 23 comes out of the annular part 15a of the valve seat 15 and the annular part 15a and the O-ring 25 are separated (no longer abutting), the liquid flow path is opened.

[0029] The lower part of the main body 11 is housed in a cylinder member 16 so that it can move back and forth. An O-ring 27 is also fitted around the outer periphery of the part housed in the cylinder member 16. The O-ring 27 fitted around the lower part of the main body 11 is always in contact with the inner circumferential surface of the cylinder member 16, thereby sealing the cylinder member 16 so that liquid does not enter.

[0030] The valve body 13 also has a pressure action surface on which the pressure of the liquid acts when the valve body 13 is opened. In this embodiment, the pressure action surface is made up of two action surfaces: a first pressure action surface 29 which is the lower surface of the protrusion 9a, and a second pressure action surface 31 which is the upper surface of the main body 11. In order to ensure that when the pressure of the liquid acts on the two acting surfaces, the pressure acts in a direction that opens the valve element 13, the protruding portion 9a is formed to have a smaller diameter than the main body portion 11. The reason for this will be explained in detail later in the explanation of operation.

[0031] <Valve seat> The valve seat 15 normally abuts against the main body 11 of the valve element 13 to close the liquid flow path, 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 Fig. 2(a), the valve is closed when the O-ring 25 provided on the insertion portion 23 of the main body 11 abuts against the inner circumferential surface of the annular portion 15a of the valve seat 15, so that the biasing force for keeping the valve disc 13 seated can be reduced compared to the conventional example shown in Fig. 7(a) where the valve is closed when the corner of the valve seat 41 abuts against the O-ring 43 of the valve disc 39. Reducing the biasing force for keeping the valve closed can further enhance the effects of the present invention, which will be explained in detail later in the explanation of operation.

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

[0033] <Energy spring> The biasing spring 17 corresponds to the biasing means of the present invention, and biases the valve element 13 in the closing direction. The biasing spring 17 is the same as that of the conventional example, and therefore a description thereof will be omitted. As mentioned above, in this embodiment, the biasing force required to maintain the valve closed state is smaller than that of the conventional example, so the biasing force F of the biasing spring 17 of this embodiment is 1S(min) is the biasing force F of the biasing spring 17 of the conventional example. 1S(min) shall be smaller than

[0034] <Operation lever> Operating lever 19 operates shaft portion 9 of valve element 13 to push valve element 13 down in the opening direction, and is normally in the "closed position" state shown in Fig. 1. When an operator grips operating lever 19 together with supply pipe 5 with the hand that holds supply pipe 5, operating lever 19 rotates around operating lever shaft 33 toward the "fully open position." As the operating lever 19 rotates, a protrusion 19a provided on the operating lever 19 presses the upper end of the shaft portion 9 downward, depressing the valve body 13 and opening the liquid flow path (see FIG. 2(b)).

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

[0036] In the conventional example of FIG. 8(a), the biasing force F of the biasing spring 17 1S(min) In addition, a force F in the valve closing direction due to the pressure of the liquid 34 1P However, in this embodiment, the lower surface of the main body 11 of the valve body 13 is housed in the cylinder member 16, so the pressure of the liquid 34 does not act on the lower surface of the main body 11, and the force F 1P does not occur. Therefore, when the valve is closed, the force acting in the valve closing direction is the biasing force F of the biasing spring 17. 1S(min) Therefore, the operator gradually increases the force with which he grips the operating lever 19 to apply a force F o F 1S(min) Increase it so that it is equal to or greater than this.

[0037] F o >F 1S(min) As shown in Figure 4(a), the force F o The shaft portion 9 is pushed down by the force, and the valve element 13 descends. When the valve element 13 descends, the insertion portion 23 comes out of 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, thereby connecting the primary valve side and the secondary valve side. When the primary side and secondary side of the valve are connected 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 action surface 29 and the second pressure action 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 protruding portion 9a, a force F in the valve closing direction is generated, as in the conventional example. 2P works. 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 3P works.

[0039] The force F in the valve opening direction, which did not occur in the conventional example of Fig. 9(a), 3P However, the reason why this occurs in this embodiment is as follows. First, the force F in the valve closing direction due to the pressure of the liquid 34 described above 1P and F 2P Both of these are caused by a pressure difference in the space separated by the O-rings 43 and 21 fitted to the valve body 13. For example, in the closed state of the conventional valve shown in Figure 8(a), the internal pressure on the primary valve side and the secondary valve side separated by the O-ring 43 is the pressure of the liquid 34 (pump pressure), while the internal pressure on the secondary valve side is atmospheric pressure. Therefore, when the pressure of the liquid 34 acts on the underside of the main body 37, an upward pressing force is generated because the pressure on the upper side of the main body 37 is small, and a force F in the valve closing direction is generated. 1p This becomes: 9(a) or the present embodiment in FIG. 4(a), in the valve open state, with respect to the pressure inside and outside the supply pipe 5 separated by the O-ring 21 fitted to the protruding portion 9a, the internal pressure of the supply pipe 5 is the pressure of the liquid 34 (pump pressure), whereas the pressure outside 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 protruding portion 9a, an upward pressing force is generated because the pressure on the upper side of the protruding portion 9a is small, and a force F in the valve closing direction is generated. 2p This becomes:

[0040] Similarly, in the present embodiment shown in Fig. 4, with respect to the internal space between the supply pipe 5 and the cylinder member 16 separated by the O-ring 27 fitted to the bottom 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, and a force F in the valve opening direction is generated. 3p This is what happens.

[0041] In this way, when the valve is opened and the liquid 34 flows into the secondary side of the valve, the pressure of the liquid 34 acts on the first pressure action surface 29 and the second pressure action surface 31, and two opposing forces F 2p , F 3p However, in this embodiment, the force F 3p The first pressure action surface 29 and the second pressure action surface 31 are configured so that the pressure applied to the first pressure action surface 29 is larger than the pressure applied to the second pressure action surface 31. This point will be explained below. As described above, the force due to the pressure of the liquid 34 increases in accordance with the size (outer diameter) of the acting surface on which the pressure of the liquid 34 acts. The size of the acting surface increases in accordance with the cross-sectional area of the portion where the acting surface is provided.

[0042] As described above, the protrusion 9a on which the first pressure action surface 29 is provided is formed to have a smaller diameter than the main body 11 on which the second pressure action surface 31 is provided. Therefore, the force F acting on the first pressure action surface 29 2P is the force F acting on the second pressure acting surface 31 3P It becomes smaller. Therefore, immediately after the valve opens, two opposing forces F 2p , F 3p occurs, but F 2P <F 3P Therefore, the force in the valve closing direction immediately after the valve is opened (F 1S(min) +F 2P -F 3P ) is the force in the valve closing direction when the valve is closed (F 1S(min) ) becomes smaller.

[0043] As described above, in this embodiment, the biasing force F of the biasing spring 17 when the valve is closed is 1S(min) is smaller than that of the conventional example. 1S(min) When the value of the force acting in the valve closing direction is small, the effect of reducing the force acting in the valve closing direction becomes relatively large. Therefore, the operator can open the valve with less force than in the conventional example, and furthermore, immediately after the valve is opened, the operator feels that the force resisting the operation of the operating lever 19 is significantly reduced (see FIG. 4(b)).

[0044] After the valve is opened, as in the conventional example, the biasing spring 17 contracts as the valve opening increases, and the biasing force F 1S Since the force F required to push down the valve element 13 becomes larger, o 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) ), so the valve can be fully opened without increasing the operating force from the force applied just before the valve is opened (see Figures 5(a) and 5(b)).

[0045] As described above, according to this embodiment, the force resisting valve operation is greatly reduced immediately after the valve is opened by providing a pressure acting surface configured so that when the valve element 13 is opened, the pressure of the liquid acts in a direction that opens the valve element 13. Furthermore, the force required to fully open the valve is smaller than the force required to open the valve. Therefore, when an operator operates the on-off valve device 7, the lever can be gripped to the maximum using only the force required to open the valve, which makes it less likely that an operator will interrupt the operation and leave the valve in a partially open state as in the past, and prevents separation of the liquid components and clogging due to 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 inner surface of the annular portion 15a abuts against the O-ring 25 of the insertion portion 23. However, the present invention is not limited to this, and the valve may be closed when the O-ring 43 of the valve body 39 abuts against a corner of the valve seat 41, as in the conventional example. However, this embodiment is preferable because it is possible to reduce the biasing force of the biasing spring 17 and the valve opens with a light force, making it less likely that the valve will be used with an extremely small opening.

[0047] Furthermore, although this embodiment is configured so that the operating force required to fully open the valve is smaller than the operating force required to open the valve, the present invention is not limited to this. The present invention was devised with the aim of preventing the valve from being used with an extremely small opening, and is effective because if the pressure of the liquid acts in a direction that opens the valve body, it becomes less likely that the valve will be used with an extremely small opening. However, this embodiment is more preferable because it allows the valve to be fully open without increasing the force applied when the valve is opened, and the degree of opening of the valve is stable. [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 seat 15a Circular part 16 Cylinder parts 17. Biasing spring 19 Operating lever 19a Convex part 21 O-ring (protrusion) 23 Insertion section 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 Clogging 50 Injector (conventional example)

Claims

1. 1. An on-off valve device that is provided upstream of a nozzle in an injection device that supplies a liquid containing powder to a nozzle at a predetermined pressure and injects the liquid from the nozzle, and that opens and closes a flow path leading to the nozzle, a valve body having an operating portion, a valve seat, a biasing means for biasing the valve body in a closing direction, and an operating lever for operating the operating portion to press down the valve body in an opening direction, an opening / closing valve device characterized in that the valve body has a pressure action surface on which the pressure of the liquid acts when the valve body is opened, and the pressure action surface is configured so that when the pressure of the liquid acts, the pressure acts in a direction that opens the valve body.

2. 2. The opening and closing valve device according to claim 1, wherein the valve seat has an annular portion, the valve body has an insertion portion that can be inserted into the annular portion, and the valve is closed when the insertion portion of the valve body is inserted into the annular portion of the valve seat and abuts against the inner surface of the annular portion, and the valve is open when the insertion portion and the annular portion do not abut.

3. a cylinder member that guides a portion of the valve body so that the portion can move back and forth; 3. The on-off valve device according to claim 1, wherein the biasing means is housed in the cylinder member, and the cylinder member is sealed to prevent the liquid from entering the cylinder member.

Images