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 added with a powdery additive may be injected onto a target object. As an example of such a liquid, there is, 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 the fire extinguishing workers 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 swellable layered clay minerals and light-shielding pigments in water.

[0003] Also, as another example of a liquid containing powder, there is the "flame spread prevention agent" disclosed in Patent Document 2. Old houses equipped with a thatched roof or other plant roofs are at high risk of ignition and flame spread due to flying fire from a surrounding fire. Therefore, as a flame spread prevention measure, it may be necessary to spray fire extinguishing water on such houses. However, the plant roof easily allows the sprayed fire extinguishing water to flow out, and it was necessary to continuously spray the fire extinguishing water. Therefore, by using a flame spread prevention agent such as that in Patent Document 2, a high-viscosity flame spread prevention agent 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 prevention agent 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. As the injection device, for example, there are those in which the above liquid is stored in a backpack tank or the like and carried by an operator, and the liquid is supplied from the tank to a nozzle at a predetermined pressure and injected. 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. As the on-off valve device, for example, a manual on-off valve device in which an operator manually moves a lever to open and close the flow path is known.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in an injection device that injects a liquid containing powder, when using the above-described manual on-off valve device, there are the following problems.

[0007] In a manual on-off valve device, normally, the valve body is pressed against the valve seat by a spring and is in a closed state. On the other hand, when an operator operates by tilting the lever or the like, the spring is compressed, and as the spring is compressed, the valve body separates from the valve seat and the valve opens. The opening degree of the valve increases according to the angle at which the lever is tilted. However, as the opening degree of the valve increases, the spring compresses and the repulsive force of the spring also increases. Therefore, the operator needs to operate the lever while gradually increasing the operating force applied to the lever. When the lever is tilted to the maximum, the valve is fully open. However, if the force applied by the operator to the lever is stopped halfway, it may be used in a half-open state.

[0008] However, when continuous use is made with a small gap between the valve body and the valve seat, there is a problem that the powder in the liquid stays in the gap between the valve body and the valve seat and the components are separated. In addition, there is also a problem that the gap between the valve body and the valve seat is gradually clogged by the retained powder, causing the on-off valve device to malfunction.

[0009] The present invention has been made to solve such problems, and in a manual on-off valve device used in an injection device for injecting a liquid containing powder, it is an object to provide an on-off valve device that prevents use in an intermediate open state and prevents separation of liquid components and clogging due to powder in the liquid.

Means for Solving the Problems

[0010] (1) The on-off valve device according to the present invention is provided on the upstream side of a nozzle in an injection device that supplies a liquid containing powder to the nozzle at a predetermined pressure and injects it from the nozzle, and opens and closes a flow path leading to the nozzle. It includes a valve body having an operation part, a valve seat, biasing means for biasing the valve body in the closing direction, and an operation lever for operating the operation part to push down the valve body in the opening direction. 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 such that when the pressure of the liquid acts, the pressure acts in the direction of opening the valve body.

[0011] (2) Further, in the one described in (1) above, the valve seat has an annular part, the valve body has an insertion part that can be inserted into the annular part, and when the insertion part of the valve body is inserted into the annular part of the valve seat and abuts against the inner peripheral surface of the annular part, the valve is in a closed state, and when the insertion part and the annular part do not abut, the valve is in an open state.

[0012] (3) Further, in the one described in (1) or (2) above, it has a cylinder member that guides a part of the valve body to be able to advance and retreat, the biasing means is accommodated in the cylinder member, and the cylinder member is sealed so that the liquid does not enter.

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 opened, and 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, immediately after the valve is opened, the force resisting the valve operation is greatly reduced. Furthermore, by configuring the pressure of the liquid when the valve body is opened to act 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 grip the lever to the fully open state with the same force applied to the lever until immediately before the valve is opened. Accordingly, a situation of a semi-open state as in the conventional case is less likely to occur, and it is possible to prevent liquid component separation and clogging due to powder in the liquid.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

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Figure 5

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Figure 8

Figure 9

Figure 10

Figure 11

Best Mode for Carrying Out the Invention

[0015] Prior to the description of the on-off valve device according to an embodiment of the present invention, first, a conventional manual on-off valve device and its problems will be described in detail. The injection device 50 in which the conventional on-off valve device 35 was provided injects a liquid containing powder (hereinafter simply referred to as "liquid"). As shown in the cross-sectional view of FIG. 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 in the tank to the nozzle 3, and a pump (not shown) for sending the liquid in the tank to the supply pipe 5 at a predetermined pressure. Instead of the pump, the liquid in the tank may be sent to the water supply pipe 5 by gas pressure.

[0016] The conventional on-off valve device 35 includes a valve body 39 provided inside the supply pipe 5 and composed of a shaft portion 9 and a main body portion 37, a valve seat 41, a biasing spring 17 for biasing the valve body 39 in the closing direction, and an operation lever 19 provided outside the supply pipe 5 for operating the shaft portion 9 to push down the valve body 39 in the opening direction. The shaft portion 9 is composed of a protruding portion 9a that penetrates the pipe wall of the supply pipe 5 and protrudes outside the supply pipe 5, and a small-diameter portion 9b that is arranged inside the supply pipe 5 and has a smaller diameter than the protruding portion 9a. An O-ring 21 is fitted on the outer periphery of the protruding portion 9a, and seals the portion penetrating the supply pipe 5 so as to be vertically movable.

[0017] An O-ring 43 is also fitted on the outer periphery of the main body portion 37 of the valve body 39. Normally, the main body portion 37 is pressed against the valve seat 41 by the biasing spring 17, so that the O-ring 43 is in close contact with the valve seat 41, and the valve is in a closed state (see FIG. 7(a)).

[0018] In use, the operator holds the supply pipe 5 and grasps the operation lever 19 with the same hand, and tilts it from the "closed position" in FIG. 6 to the "fully open position" 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, in the conventional on-off valve device 35, the operator opens the valve by grasping the operation lever 19 (tilting 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 with reference to 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 compression amount 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 , F 1PIn order to push down the valve body 39 against it, F 1S +F 1P It is necessary to apply the above force to the shaft portion 9. Therefore, as shown in Fig. 8(b), the operator gradually increases the force applied to the shaft portion 9 by gradually increasing the force of gripping the operation lever 19, and increases the force F o applied to the shaft portion 9.

[0021] F o >F 1S +F 1P When it becomes, as shown in Fig. 9(a), the shaft portion 9 is pushed down by the force F o and the valve body 39 descends. When the valve body 39 descends, the O-ring 43 that was in close contact with the valve seat 41 separates from the valve seat 41, and the primary side and the secondary side of the valve communicate with each other. When the primary side and the secondary side of the valve communicate with each other and the liquid 34 flows into the secondary side of the valve, the primary side and the secondary side of the valve become the same pressure, so the force F 1P in the valve closing direction due to the pressure of the liquid 34 does not act. On the other hand, a new force F 2P in the valve closing direction is generated by the liquid 34 that has flowed into the secondary side of the valve. Specifically, the pressure of the liquid 34 acts on the lower surface of the protruding portion 9a by the liquid 34 filled in the secondary side of the valve, and the force F 2P acts in the upward direction, that is, the valve closing direction.

[0022] The force F 1P and F 2P in the valve closing direction due to the pressure of the liquid 34 increases according to the size (outer diameter) of the working surface on which the pressure of the liquid 34 acts. And the size of the working surface increases according to the cross-sectional area of the part where the working surface is provided (specifically, the cross-sectional area of the part separating the atmospheric pressure part and the part filled with the liquid 34). That is, the force F 1P acting with the lower surface of the main body portion 37 of the valve body 39 as the working surface has a magnitude corresponding to the cross-sectional area of the portion shown by the broken-line circle in Fig. 8(a) of the main body portion 37, and the force F 2P acting with the lower surface of the protruding portion 9a as the working surface has a magnitude corresponding to the cross-sectional area of the portion shown by the broken-line circle in Fig. 9(a) of the protruding portion 9a.

[0023] In this example, since the cross-sectional area of the portion shown by the dashed circle in Fig. 9(a) is smaller than the cross-sectional area of the portion shown by the dashed circle in Fig. 8(a), F 1P >F 2P results. Therefore, the force acting in the valve closing direction is smaller immediately after valve opening (F 1S(min) +F 1P ) than when the valve is closed (F 1S(min) +F 2P ). As shown in Fig. 9(b), the force required to push down the valve body 39 temporarily decreases immediately after valve opening. Strictly speaking, since the biasing spring 17 immediately after valve opening is compressed more than when the valve is closed, the biasing force is larger than F 1S(min) , but since the increment is negligible, it is ignored here.

[0024] As described above, the force acting in the valve closing direction temporarily decreases immediately after valve opening. However, as the valve opening degree increases thereafter, the biasing spring 17 compresses and the biasing force F 1S increases, so the force acting in the valve closing direction also increases. Specifically, the force acting in the valve closing direction gradually increases from the force F 1S(min) +F 2P when the valve is immediately opened in Fig. 9(a) to the force F 1S(max) +F 2P when the valve is fully open in Fig. 10(a). Therefore, as shown in Fig. 10(b), the operator operates the operation lever 19 so as to gradually increase the force F o applied to the shaft portion 9 by gradually increasing the force of gripping the operation lever 19. When the operation lever 19 is tilted 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, after the valve is opened, the opening degree of the valve increases as the operator gradually increases the force of grasping the operation lever 19. Therefore, depending on the operator's force control, it is easy to hold the operation lever 19 in a half-open state. For example, if the operation lever 19 is held immediately after the valve is opened and the water discharge is continued while the opening degree is small, the powder dispersed in the liquid 34 tends to stay between the valve body 39 and the valve seat 41, and as a result, clogging 45 due to powder as shown in FIG. 11 may occur. The clogging 45 due to powder in the liquid 34 is a problem because it causes component separation of 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 the present embodiment, the injection device 1 is prevented from being used in a half-open state, so that clogging 45 due to powder in the liquid 34 as described above can be prevented. This will be described in detail below with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view showing a part of the injection device 1 in which the on-off valve device is provided, and FIGS. 2(a) and 2(b) are partial enlarged views showing the closed state and the fully open state of the on-off valve device. In FIGS. 1 and 2, the same reference numerals are given to the same or corresponding parts as those in FIGS. 6 and 7 for explaining the conventional example.

[0027] The on-off valve device 7 of the present embodiment is provided on the upstream side 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, similar to the conventional example. As shown in FIG. 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 to be able to advance and retreat, a biasing spring 17 that biases the valve body 13 in the closing direction, and an operation lever 19 that operates the shaft portion 9 to push down the valve body 13 in the opening direction. Each configuration will be described in detail below.

[0028] <Valve body> The valve body 13 normally abuts against the valve seat 15 to close the liquid flow path, and is composed of a shaft portion 9 corresponding to the operation portion of the present invention and a main body portion 11. The shaft portion 9 has, as in the conventional example, a protruding portion 9a that penetrates the pipe wall of the supply pipe 5 and protrudes outside the supply pipe 5, and a small-diameter portion 9b having a diameter smaller than that of the protruding portion 9a. The main body portion 11 has an insertion portion 23 that can be inserted into an annular portion 15a of a valve seat 15 described later, and an O-ring 25 is fitted on the outer periphery of the insertion portion 23. When the insertion portion 23 is inserted into the annular portion 15a of the valve seat 15, the outer peripheral portion of the O-ring 25 abuts against the inner peripheral surface of the annular portion 15a, and the liquid flow path is closed. Also, when the insertion portion 23 comes out of the annular portion 15a of the valve seat 15 and the annular portion 15a and the O-ring 25 are separated (do not abut), the liquid flow path is opened.

[0029] Also, the lower part of the main body portion 11 is accommodated in a cylinder member 16 so as to be able to advance and retreat. And an O-ring 27 is also fitted on the outer periphery of the portion accommodated in the cylinder member 16. By the O-ring 27 fitted on the lower part of the main body portion 11 always abutting against the inner peripheral surface of the cylinder member 16, it seals so that liquid does not enter the cylinder member 16.

[0030] Also, the valve body 13 has a pressure acting surface on which the liquid pressure acts when the valve body 13 is opened. The pressure acting surface of the present embodiment is composed of two acting surfaces, a first pressure acting surface 29 that is the lower surface of the protruding portion 9a and a second pressure acting surface 31 that is the upper surface of the main body portion 11. In order for the pressure to act in the direction of opening the valve body 13 when the liquid pressure acts on the above two acting surfaces, the protruding portion 9a is formed to have a smaller diameter than the main body portion 11. The reason for this will be described in detail in the operation explanation described later.

[0031] <Valve seat> The valve seat 15 normally abuts against the main body portion 11 of the valve body 13 to close the liquid flow path, and has an annular portion 15a into which the insertion portion 23 of the main body portion 11 can be inserted. In this embodiment, as shown in Fig. 2(a), the O-ring 25 provided on the insertion portion 23 of the main body portion 11 abuts against the inner peripheral surface of the annular portion 15a of the valve seat 15 to achieve a valve closing state. Compared with the case where the valve is in a closed state by the contact between the corner portion of the valve seat 41 and the O-ring 43 of the valve body 39 as in the conventional example shown in Fig. 7(a), the biasing force for maintaining the seated state of the valve body 13 can be reduced. Reducing the biasing force for maintaining the valve closed state can further achieve the effects of the present invention. This will be described in detail in the operation explanation below.

[0032] <Cylinder member> The cylinder member 16 guides a part of the valve body 13 (specifically, the lower part of the main body portion 11) so as to be able to advance and retreat. An urging spring 17 is accommodated in the cylinder member 16. As described above, since the O-ring 27 provided at the lower part of the main body portion 11 always abuts against the inner peripheral surface of the cylinder member 16, no liquid enters the portion where the urging spring 17 of the cylinder member 16 is accommodated. Therefore, the internal pressure of the cylinder member 16 is about atmospheric pressure.

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

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

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

[0036] In the conventional example of Fig. 8(a), in addition to the biasing force F of the biasing spring 17, the force F in the valve closing direction due to the pressure of the liquid 34 acts. However, in the present embodiment, since the lower surface of the main body portion 11 of the valve body 13 is accommodated 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 the force F 1S(min) does not occur. 1P Therefore, the force acting in the valve closing direction when the valve is in the closed state is only the biasing force F of the biasing spring 17. Therefore, as shown in Fig. 3(b), the operator gradually increases the force of grasping the operation lever 19 and applies the force F 1P to the shaft portion 9 so as to be equal to or greater than F When F 1S(min) > F o becomes, as shown in Fig. 4(a), the shaft portion 9 is pushed down by the force F 1S(min) and the valve body 13 descends. When the valve body 13 descends, the insertion portion 23 comes out of the annular portion 15a of the valve seat 15, the O-ring 25 of the insertion portion 23 separates from the valve seat 15, and the primary side and the secondary side of the valve communicate with each other.

[0037] F o > F 1S(min) When this occurs, as shown in Fig. 4(a), the shaft portion 9 is pushed down by the force F o and the valve body 13 descends. When the valve body 13 descends, the insertion portion 23 comes out of the annular portion 15a of the valve seat 15, the O-ring 25 of the insertion portion 23 separates from the valve seat 15, and the primary side and the secondary side of the valve communicate with each other. When the primary side and the secondary side of the valve communicate and the liquid 34 flows into the secondary side of the valve, the pressure of the liquid 34 filled in the secondary side of the valve acts on the first pressure acting surface 29 and the second pressure acting surface 31 of the valve body 13. When the primary side and the secondary side of the valve communicate and the liquid 34 flows into the secondary side of the valve, the pressure of the liquid 34 filled in the secondary side of the valve acts on the first pressure acting surface 29 and the second pressure acting 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 acts as in the conventional example. 2P acts. 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 portion 11, a force F in the downward direction, that is, the valve opening direction, acts. 3P acts.

[0039] The force F in the valve opening direction that did not occur in the conventional example of FIG. 9(a) occurs in this embodiment for the following reasons. 3P 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 are both generated 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 valve closed state of the conventional example shown in FIG. 8(a), with respect to the primary side and secondary side 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 the atmospheric pressure. Therefore, when the pressure of the liquid 34 acts on the lower surface of the main body portion 37, since the pressure above the main body portion 37 is low, a pressing force is generated in the upward direction, resulting in the force F in the valve closing direction 1p to be. Also, in the valve open state as in the conventional example of FIG. 9(a) or the present embodiment of FIG. 4(a), with respect to the pressures 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), while the external pressure of the supply pipe 5 is the atmospheric pressure. Therefore, when the pressure of the liquid 34 acts on the lower surface (first pressure acting surface) of the protruding portion 9a, since the pressure above the protruding portion 9a is low, a pressing force is generated in the upward direction, resulting in the force F in the valve closing direction 2p to be.

[0040] Similarly, in the present embodiment of FIG. 4, regarding the supply pipe 5 and the internal space of the cylinder member 16 separated by the 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 the 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, since the pressure on the lower side of the main body 11 is small, a downward pressing force is generated, and the force F in the valve opening direction 3p is obtained.

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

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

[0043] Also, as described above, in the present embodiment, the biasing force F of the biasing spring 17 at the time of valve closure 1S(min) is smaller than that of the conventional example. When the biasing force F of the biasing spring 17 1S(min) is small, the effect of reducing the force in the valve closing direction described above becomes relatively large. Therefore, the operator can open the valve with a smaller force than in the conventional example, and furthermore, immediately after valve opening, it feels as if the force resisting the operation of the operation lever 19 is significantly reduced (see Fig. 4(b)).

[0044] After valve opening, as in the conventional example, as the opening degree of the valve increases, the biasing spring 17 contracts and the biasing force F 1S increases, so the force F o required to push down the valve body 13 also increases. However, in the present embodiment, the force in the valve opening direction due to the pressure of the liquid 34 (= F 3P - F 2P ) is configured to be larger than 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 immediately before valve opening (see Figs. 5(a) and 5(b)).

[0045] As described above, according to the present embodiment, by having the pressure acting surface configured such that the pressure of the liquid acts in the direction of opening the valve body 13 when the valve body 13 is opened, immediately after valve opening, the force resisting valve operation is significantly reduced. Furthermore, the force required to fully open the valve is smaller than the force required for valve opening. Therefore, when the operator operates the on-off valve device 7, since the operator can grip the lever to the maximum with only the force required for valve opening, the situation where the operator interrupts the operation and uses it in the half-open state as in the conventional case is less likely to occur, and component separation of the liquid and clogging due to powder in the liquid can be prevented.

[0046] In the present embodiment, 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 abuts against the inner peripheral surface of the annular portion 15a to bring the valve into a closed state. However, the present invention is not limited to this. For example, as in the conventional example, the O-ring 43 of the valve body 39 may abut against the corner portion of the valve seat 41 to bring the valve into a closed state. However, in the present embodiment, the biasing force of the biasing spring 17 can be reduced, and the valve can be opened with a small force. Therefore, it is difficult for a situation to occur in which the valve is used in a state where the opening degree of the valve is extremely small, which is preferable.

[0047] Also, in the present embodiment, the operating force required to fully open the valve is configured to be smaller than the operating force required to open the valve. However, the present invention is not limited to this. The present invention was devised for the purpose of preventing the valve from being used in a state where the opening degree of the valve is extremely small. If the liquid pressure acts in the direction of opening the valve body, at least the situation where the valve is used in a state where the opening degree of the valve is extremely small is less likely to occur. Therefore, the present invention has an effect. However, in the present embodiment, the valve can be fully opened without increasing the force applied when the valve is opened. Therefore, the opening degree of the valve is more preferably stable.

Explanation of Reference Numerals

[0048] 1 Injector 3 Nozzle 5 Supply Pipe 7 On-Off Valve Device 9 Shaft Portion 9a Protrusion 9b Small-Diameter Portion 11 Main Body Portion 13 Valve Body 15 Valve Seat 15a Annular Portion 16 Cylinder Member 17 Biasing Spring 19 Operating Lever 19a Convex Portion 21 O-Ring (Protrusion) 23 Insertion Portion 25 O-Ring (Insertion Portion) 27 O-Ring (Main Body Portion) 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 part (conventional example) 39 Valve body (conventional example) 41 Valve seat (conventional example) 43 O-ring (conventional example) 45 Clogging 50 Injection device (conventional example)

Claims

1. An on-off valve device provided upstream of a nozzle in an injection device that supplies a liquid containing powder to the nozzle at a predetermined pressure and injects it from the nozzle, the on-off valve device opening and closing a flow path leading to the nozzle, comprising: a valve body having an operation part, a valve seat, biasing means for biasing the valve body in a closing direction, and an operation lever for operating the operation part to push down the valve body in an opening direction; 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 such that when the pressure of the liquid acts, the pressure acts in a direction to open the valve body. An on-off valve device characterized by this.

2. The valve seat has an annular part, the valve body has an insertion part that can be inserted into the annular part, and when the insertion part of the valve body is inserted into the annular part of the valve seat and abuts against the inner peripheral surface of the annular part, the valve is in a closed state, and when the insertion part and the annular part do not abut, the valve is in an open state. The on-off valve device according to Claim 1, characterized by this.

3. having a cylinder member that guides a part of the valve body to be movable forward and backward; The on-off valve device according to Claim 1 or 2, characterized in that the biasing means is accommodated in the cylinder member and the cylinder member is sealed so that the liquid does not enter.

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