High-pressure water jet pump

Abstract

To create a new operating mode in which a portion of the high-pressure water discharged from a discharge port of a plunger pump body can be stably and continuously extracted, thereby shifting the discharge pressure and discharge flow rate of the high-pressure water from a normal operating mode to a desired level and shifting it to a lower pressure side.SOLUTION: A bypass pipe 81, which directly or indirectly communicates with a spillway pipe 15, is connected across a discharge pipe 17. A high-pressure water jet sprayer 83, which sprays high-pressure water in a form of a jet water stream JW, is connected to a tip opening of the bypass pipe 81. The high-pressure water jet sprayer 83 is disposed inside a jet water stream collision section 84 having a cylindrical wall surface 84ab, so that the jet water stream JW is repeatedly reflected at a cylindrical wall surface 84ab, causing reflected water streams to collide with each other multiple times, thereby stably and quickly consuming its own energy (head). The water stream that has consumed its energy flows into the spillway pipe 15.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a high-pressure water jet pump, and more specifically, to a high-pressure water jet pump that can stably and continuously extract a portion of the high-pressure water discharged from the discharge port of the plunger pump body, thereby creating a new operating mode in which the discharge pressure and discharge flow rate of the high-pressure water are shifted to a lower pressure side by uniformly reducing them from the normal operating mode to a desired level, thereby making it possible to stably reduce the discharge flow rate at idling speed and to use a plunger pump with a large rated discharge flow rate in a water jet combined pressure-in construction method, etc., resulting in a highly versatile high-pressure water jet pump. [Background technology]

[0002] A water jet combined press-in method, in which a press-in machine and high-pressure water are used to drive sheet piles and other piles into the ground to be used as water-stopping means in revetment construction and the like, is widely known (see, for example, Non-Patent Document 1). The water jet combined press-in method uses a high-pressure water jet pump to pump high-pressure water. The high-pressure water jet pump sprays high-pressure water from a spray nozzle attached to the tip of the discharge line into the ground in the form of a jet of water (high-pressure jet water), reducing the penetration resistance of the pile into the ground and making it easier for the press-in machine to press the pile into the ground.

[0003] As shown in Figure 14, a high-pressure water jet pump consists of a pump body that supplies high-pressure water and an engine that provides rotational power to the pump body. Since high discharge pressure with a small discharge flow rate is required for the pump body, a positive displacement, reciprocating plunger pump is often used. Furthermore, for the engine body, a turbocharged diesel engine is often used, which is capable of generating high torque at low revolutions, has a simple mechanism, and is inexpensive to maintain.

[0004] The engine output shaft on the engine side (clutch section) and the input shaft on the pump main body side are connected by a shaft connecting means (coupling or pulley). By changing the engine rotation speed, it is possible to change the discharge pressure and discharge flow rate of the pump main body. The engine rotation speed is controlled manually or remotely using the control panel on the pump main body or a remote control.

[0005] Generally, a flexible discharge line (hose piping) is connected to the pump discharge port from the outside, and the discharge line is laid out close to the tip of the pile material. A jet nozzle is connected to the end of the discharge line, which sprays high-pressure jet water into the ground. Similarly, a flexible suction line (hose piping) is connected to the pump suction port from the outside, and the suction line is connected to a water tank. The water source for the water tank is river water or seawater pumped up by pump in the case of bank protection work, and water is transported by water truck and supplied to the water tank in the case of land work away from rivers or the sea.

[0006] In addition, a safety valve is provided between the pump discharge port and the discharge block, and when the pressure of the high-pressure water exceeds the set pressure of the safety valve, the safety valve opens and connects to the pump spill pipe, and the excess high-pressure water equivalent to the excess pressure exceeding the set pressure is returned to the water tank through the spill line (hose piping).

[0007] Fig. 15 is a graph showing an example of the correlation characteristics between "engine speed and discharge pressure of the pump body at that speed" and "engine speed and discharge flow rate of the pump body at that speed" of a conventional high-pressure water jet pump. The horizontal axis represents engine speed (rpm), and the vertical axis represents discharge pressure (MPa) and discharge flow rate (L / min). "Pn" in Fig. 15(a) represents the maximum normal discharge pressure (MPa), and "Fn" in Fig. 15(b) represents the maximum normal discharge flow rate (L / min). Fig. 16 is a graph showing an example of the correlation characteristics between discharge pressure and discharge flow rate of the pump body.

[0008] As shown in Figure 15(a), a high-pressure water jet pump can achieve a maximum discharge pressure of Pn+5 (MPa) at an engine speed of 1800 (rpm). However, the normal pressure range of the pump discharge pressure used in the water jet combined press-in method is, for example, Pn-3.25 to Pn (MPa), in which case the normal engine speed range is 1100 to 1350 (rpm). Therefore, a pressure range exceeding the normal maximum discharge pressure Pn (MPa) and an engine speed range exceeding 1350 (rpm) will not be used.

[0009] Similarly, as shown in Figure 15(b), a high-pressure water jet pump can achieve a maximum discharge flow rate of Fn+53 (L / min) at an engine speed of 1800 (rpm), but the normal flow rate range of the pump discharge flow rate used in the water jet combined press-in method is, for example, Fn-43 to Fn (L / min). Therefore, a flow rate range exceeding the normal maximum discharge flow rate Fn (L / min) and an engine speed range exceeding 1350 (rpm) will not be used.

[0010] As shown in Figure 16, the discharge pressure and discharge flow rate of a conventional high-pressure water jet pump have an almost linear relationship, and a pressure range exceeding the maximum normal discharge pressure Pn (MPa) and a flow rate range exceeding the maximum normal discharge flow rate Fn (L / min) are not used.

[0011] Incidentally, there is a known invention relating to a high-pressure washer in which a pressure regulating valve is provided midway in the discharge line inside the plunger pump as a means for regulating the discharge pressure of the plunger pump, and a spill water line inside the plunger pump, which is connected to a water tank, is further connected to the pressure regulating valve, and excess high-pressure water equivalent to the excess pressure exceeding the set pressure of the pressure regulating valve is returned to the water tank through the spill water line, thereby making the pressure in the discharge line inside the plunger pump equal to the set pressure (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Patent No. 7377397 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-136165 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-276187 [Non-patent literature]

[0013] [Non-Patent Document 1] https: / / www.giken.com / ja / technology / principle / penetration_tech / water_jetting / Summary of the Invention [Problem to be solved by the invention]

[0014] In order to minimize the impact of high-pressure water sprayed from the spray nozzle on the surrounding ground and to ensure the bearing capacity of the ground after the piles are driven in, it is necessary to minimize the pressure and flow rate of the high-pressure water sprayed from the spray nozzle when using the water jet combined press-in method, for example, during press-in in ground with low press-in load, during pile joint welding work, and during weld inspection.

[0015] Furthermore, at the start of construction (when the engine is idling), especially when the tip of the pile (sheet pile) is close to the ground surface, if the high-pressure water sprayed from the nozzle is large in volume and pressure, the water will splash over a wide area and hinder the work of surrounding workers. For this reason, users have requested that the pressure and flow rate of the high-pressure water sprayed from the nozzle be reduced as much as possible when the engine is idling, to prevent water from splashing.

[0016] Furthermore, water must be transported by sprinkler truck and supplied to the water tank, and in order to reduce the number and amount of water supplies, there is a demand from users to reduce as much as possible the amount of high-pressure water sprayed from the spray nozzle at the start of construction, during injection in ground with low injection load, during pile welding work and welding inspection.

[0017] On the other hand, the discharge flow rate of the pump body decreases as the engine speed is reduced. Therefore, by lowering the engine's idling speed, the discharge flow rate of the pump body at the engine's idling speed can be reduced. However, lowering the idling speed is within the scope of the engine manufacturer, and users themselves cannot lower the idling speed below the set value set by the engine manufacturer. The discharge flow rate of the pump body at the idling speed is the minimum discharge flow rate.

[0018] Therefore, when an engine manufacturer changes the engine specifications to increase the idling speed, it is necessary to ensure that the pump itself has the function to reduce the discharge flow rate in order to prevent the minimum pump discharge flow rate, which is determined by the idling speed, from increasing.

[0019] Furthermore, during busy periods when it is difficult to secure a pump that can provide the optimal discharge flow range for the target construction work, such as the water jet combined pressure injection method, even if a pump has a high rated discharge flow rate and would not normally be considered as a candidate, by ensuring that the pump itself has the function to reduce the discharge flow rate, it can still be used in the construction work.

[0020] By the way, it is conceivable to branch off a part of the discharge pipe connecting the pump discharge port and the safety valve, and to install a bypass line connected to the spillway of the pump body. Then, by installing an on-off valve in the bypass line, it is conceivable to open the valve and let some of the high-pressure water flowing through the discharge pipe flow into the spillway, thereby reducing the discharge flow rate of the pump body.

[0021] However, the pressure in the discharge pipe connecting the pump discharge port and the safety valve is at least 6.75 MPa, for example, while the pressure in the spillway pipe is atmospheric pressure (= 0 MPa). When the on-off valve is opened, the high-pressure water creates a water hammer effect that could damage the spillway. Furthermore, when the on-off valve is opened, the pressure fluctuations in the high-pressure water can cause the flow of high-pressure water through the discharge pipe to become unstable, which could also cause the flow of high-pressure water through the discharge line to become unstable.

[0022] Therefore, the present invention has been made in consideration of the above-mentioned problems of the conventional technology, and its object is to provide a high-pressure water jet pump with excellent versatility that can stably and continuously extract a portion of the high-pressure water discharged from the discharge port of the plunger pump body, thereby creating a new operating mode in which the discharge pressure and discharge flow rate of the high-pressure water are shifted to a lower pressure side by uniformly reducing them from the normal operating mode to a desired level, thereby making it possible to stably reduce the discharge flow rate at idling speed and to use a plunger pump with a large rated discharge flow rate in a water jet combined pressure-in construction method, etc. [Means for solving the problem]

[0023] The high-pressure water jet pump according to the present invention for achieving the above object comprises a plunger (5) for generating high-pressure water to increase the pressure of sucked water and make it easier for a pile material to penetrate into the ground, a safety valve (14) for releasing excess high-pressure water equivalent to the excess pressure when the pressure of the high-pressure water exceeds a set pressure, thereby making the pressure of the high-pressure water equal to or less than the set pressure, a discharge port (17a) for discharging the high-pressure water to the outside, a discharge pipe (17) for transferring the high-pressure water from the safety valve (14) to the discharge port (17a), a spillway (15a) for discharging excess water equivalent to the excess high-pressure water to the outside, and a spillway pipe (15b) for transferring the excess water from the safety valve (14) to the spillway (15a). and an engine body (30) for supplying power to the plunger (5), wherein the discharge pipe (17) is connected to a bypass pipe (81) that directly or indirectly communicates with the spill pipe (15) and crosses the discharge pipe (17), the bypass pipe (81) has an on-off valve (82) for passing / blocking the high-pressure water, and a high-pressure water jet spraying section (83) that sprays the high-pressure water in the form of a jet water stream (JW) by means of an injector (83a) "having a portion whose inner diameter is reduced to a diameter (φD1) smaller than the inner diameter (φD1) of the bypass pipe (81)," and the high-pressure water jet spraying section (83) "has a flow path cross-sectional area (πD2 2 / 4) larger than the cross-sectional area (πr 2, L 2 The jet water flow impingement section (84, 84') is connected to the wall surface (84ab, 84ab') having a wall surface (84ab, 84ab') having a wall surface (84ab, 84ab').

[0024] In the above configuration, a part of the high-pressure water flowing through the discharge pipe 17 is introduced into the bypass pipe 81 and is sprayed from the injector 83a in the form of a jet water stream JW. The jet water stream JW can be regarded as a bundle of symmetrical streamlines that form a predetermined angle with respect to the central axis 83aC of the injector, and therefore the collision of the jet water stream JW with the wall surfaces 84ab, 84ab' follows the general law of incidence and reflection.

[0025] The wall surfaces (84ab, 84ab') have a cross-sectional area (πD2 2 / 4) larger than the cross-sectional area (πr 2 , L 2 ), the jet water streams reflected at each reflection point on the wall surfaces (84ab, 84ab') collide with each other multiple times, and their energy (head) is consumed steadily and quickly. Finally, the jet water stream (JW) calms down to the point where it can no longer be reflected by the wall surfaces (84ab, 84ab') and is discharged to the outside as excess water from the spillway (15a).

[0026] In this manner, a portion of the high-pressure water discharged from the discharge port (17a) is sprayed from the injector (83a) in the form of a jet water stream (JW) and impinges on the wall surfaces (84ab, 84ab'), thereby enabling a portion of the high-pressure water to be continuously and stably extracted. As a result, the discharge pressure and discharge flow rate of the high-pressure water discharged from the discharge port (17a) are steadily reduced, thereby enabling the creation of a new operation mode in which the discharge pressure and discharge flow rate of the high-pressure water discharged from the discharge port (17a) are shifted to a lower pressure side by uniformly reducing them from the normal operation mode to a desired level.

[0027] A second feature of the high-pressure water jet pump according to the present invention is that the jet water flow collision section (84) has a T-shaped joint (84a), and the overflow pipe (15) is connected to the straight pipe portions (84b, 84c) of the T-shaped joint (84a).

[0028] In the above configuration, the jet water stream collision section (84) can be easily constructed by making minor modifications to an existing high-pressure water jet pump.

[0029] The third feature of the high-pressure water jet pump according to the present invention is that the jet water stream collision section (84') has an L-shaped joint, and the other port of the L-shaped joint to which the high-pressure water jet spraying section (83) is not connected is connected to a confluence pipe (15') that flows low-pressure water "calmed by repeated reflections of the jet water stream (JW) on the wall surfaces (84ab, 84ab')" into the spillway pipe (15).

[0030] In the above configuration, the jet water stream collision section (84') can be easily constructed by making minor modifications to an existing high-pressure water jet pump.

[0031] A fourth feature of the high-pressure water jet pump according to the present invention is that the high-pressure water jet spraying section (83) comprises an injector (83a) that sprays a jet water stream, an injector threaded joint (83b) having a male threaded portion (83bb) on a lower outer periphery and a female threaded portion (83bc) on an upper inner periphery for disposing the injector (83a) inside the jet water stream collision section (84), and a bypass pipe joint (83c) having a male threaded portion (83ca) on a lower outer periphery for connecting the bypass pipe (81) to the injector threaded joint (83b).

[0032] In the above configuration, the high-pressure water jet spraying unit (83) can be easily constructed by making minor modifications to an existing high-pressure water jet pump. In addition, since the components are fastened together with screws, maintenance such as replacement is easy.

[0033] A fifth feature of the high-pressure water jet pump according to the present invention is that the on-off valve (82) is an electromagnetic valve configured to be able to open and close by an electric signal.

[0034] In this configuration, the on-off valve (82) can be remotely controlled.

[0035] A sixth feature of the high-pressure water jet pump according to the present invention is that the opening degree of the on-off valve (82) is variable.

[0036] With the above configuration, when the engine speed is fixed, it is possible to continuously change the injection amount of the jet water (JW) injected from the injector (83a), thereby continuously changing the intermediate pressure mode between the high-pressure mode when the on-off valve (82) is fully closed and the low-pressure mode when the on-off valve (82) is fully open.

[0037] A seventh feature of the high-pressure water jet pump according to the present invention is that the overflow water discharged from the overflow outlet (15a) is returned to the water source or the water tank.

[0038] In the above configuration, it is possible to maintain the low-pressure mode, in which both the pressure and the flow rate are lower than those in the high-pressure mode, for a long period of time.

[0039] An eighth feature of the high-pressure water jet pump according to the present invention is that the on-off valve (82) is configured to be able to spray the high-pressure water in the form of a jet water stream (JW), and the high-pressure water jet spraying section (83) is omitted.

[0040] In the above configuration, the configuration of the operation mode switching unit (80'', 80A) can be simplified.

[0041] A ninth feature of the high-pressure water jet pump according to the present invention is that the jet water stream collision portion (84) is attached so that the jet water stream (JW) is parallel to a central axis (C) in the longitudinal direction of the jet water stream collision portion (84).

[0042] In the above configuration, the surface area of ​​the wall that repeatedly reflects and collides the jet water stream (JW) in the jet water stream collision section (84) is increased, so that the high-pressure water can be calmed down more quickly. [Effects of the Invention]

[0043] According to the high-pressure water jet pump of the present invention, a portion of the high-pressure water discharged from the discharge port of the plunger pump body can be stably and continuously extracted, thereby making it possible to create a new operating mode in which the discharge pressure and discharge flow rate are shifted to a lower pressure side by uniformly reducing them from the normal operating mode to a desired level.This makes it possible to stably reduce the discharge flow rate at idling speed, and to provide a highly versatile high-pressure water jet pump that can be used in a plunger pump with a large rated discharge flow rate in a water jet combined pressure-in construction method, etc. [Brief explanation of the drawings]

[0044] [Figure 1] 1 is a skeleton diagram showing a mechanism of a high-pressure water jet pump according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view illustrating a main part of an operation mode switching unit of the high-pressure water jet pump according to the present invention. FIG. [Figure 3] FIG. 2 is an explanatory diagram showing a high-pressure water jet ejecting section and a jet water stream collision section. [Figure 4] 1 is a schematic explanatory diagram showing repeated reflections and multiple collisions of a jet of water ejected from an ejector on a cylindrical wall surface. FIG. [Figure 5] 10 is a graph showing an example of correlation characteristics between "engine rotation speed and discharge pressure of the plunger pump main body at that rotation speed" and "engine rotation speed and discharge flow rate of the plunger pump main body at that rotation speed" of the high-pressure water jet pump according to the present invention. [Figure 6] 1 is a graph showing an example of correlation characteristics between discharge pressure and discharge flow rate in a plunger pump body of a high-pressure water jet pump according to the present invention. [Figure 7] 10 is a cross-sectional explanatory view of a main part showing another example of an operation mode switching unit of a high-pressure water jet pump according to the present invention. FIG. [Figure 8] 10 is a cross-sectional explanatory view of a main part showing another example of an operation mode switching unit of a high-pressure water jet pump according to the present invention. FIG. [Figure 9] FIG. 10 is an explanatory diagram showing a box-type joint that causes a jet of water to impinge on a flat wall surface. [Figure 10] 10 is a cross-sectional view illustrating a main part of an operation mode switching unit in which an electromagnetic on-off valve is arranged downstream of a high-pressure water jet ejecting unit. FIG. [Figure 11] 10 is an explanatory diagram showing an operation mode switching unit in which an electromagnetic on-off valve has the function of a high-pressure water jet spray unit. FIG. [Figure 12] 10 is an explanatory diagram showing an operation mode switching unit that is installed so that the jet water flow emitted from the electromagnetic on-off valve is parallel to the central axis of the jet water flow collision unit. FIG. [Figure 13] 10 is an explanatory diagram showing an operation mode switching unit that is installed so that the jet water flow ejected from the high-pressure water jet ejecting unit is parallel to the central axis of the jet water flow collision unit. FIG. [Figure 14] FIG. 1 is an explanatory diagram showing an example of a conventional water jet combined press-in method using a high-pressure water jet pump. [Figure 15] 10 is a graph showing an example of correlation characteristics between "engine rotation speed and discharge pressure of the plunger pump body at that rotation speed" and "engine rotation speed and discharge flow rate of the plunger pump body at that rotation speed" of a conventional high-pressure water jet pump. [Figure 16] 10 is a graph showing an example of correlation characteristics between discharge pressure and discharge flow rate in a plunger pump body of a conventional high-pressure water jet pump. DETAILED DESCRIPTION OF THE INVENTION

[0045] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0046] FIG. 1 is a skeleton diagram showing the mechanism of a high-pressure water jet pump 100 according to one embodiment of the present invention.

[0047] This high-pressure water jet pump 100 is configured to stably extract a portion of the high-pressure water flowing through the discharge pipe 17 in the form of a jet water stream JW, and to uniformly reduce the operating mode for the discharge pressure and discharge flow rate of the high-pressure water to a desired level. This makes it possible to stably reduce the discharge pressure and discharge flow rate of the high-pressure water during idling rotation speed, and the extracted jet water stream JW is calmed by repeated reflections and multiple collisions on the cylindrical wall surface 84ab and returned to the water source.

[0048] The high-pressure water jet pump 100 includes a plunger pump body 20 that pressurizes sucked water to generate high-pressure water, an engine body 30 that supplies rotational power to the plunger pump body 20, a hydraulic supply unit 40 that supplies hydraulic oil to each sliding part of the engine body 30 and the clutch 34, a fuel supply unit 50 that supplies fuel to the engine body 30, a cooling water supply unit 60 that supplies cooling water to the engine body 30, a pump control unit 70 that controls the plunger pump body 20, an operation mode switching unit 80 that selectively sets the operation mode to either a high-pressure mode or a low-pressure mode, and an engine control unit 90 that controls the engine body 30. Note that the "high-pressure mode" here refers to an operation mode in which the normal pressure range and normal flow rate range are relatively narrow but the maximum discharge pressure and maximum discharge flow rate are relatively large. Conversely, the "low-pressure mode" refers to an operation mode in which the maximum discharge pressure and maximum discharge flow rate are relatively small but the normal pressure range and normal flow rate range are relatively wide. Each component will be further described below.

[0049] The plunger pump body 20 includes a drive shaft 1 that receives rotational power from the engine body 30 and rotates the crankshaft 2, a crankshaft 2 that reciprocates a crosshead 4 along the longitudinal direction (horizontal direction), a connecting rod 3 that connects the crosshead 4 and the crankshaft 2, the crosshead 4 that transmits the pushing force (axial force) of the connecting rod 3 to the plunger 5, a plunger 5 that pressurizes the sucked water to generate high-pressure water, a packing case 6 within which the plunger 5 slides back and forth, a packing 7 that seals the gap between the plunger 5 and the packing case 6, a common block 8 that has three independent internal spaces that communicate with each of the three packing cases 6, and a suction The system is equipped with an intake block 9 that branches the intake water, a discharge block 10 that merges the high-pressure water, an intake valve 11 that only allows water to flow from the intake block 9 to the common block 8, a discharge valve 12 that only allows high-pressure water to flow from the common block 8 to the discharge block 10, a pressure sensor 13 that detects the pressure of the high-pressure water being discharged, a safety valve 14 that releases excess high-pressure water equivalent to the amount of high-pressure water that exceeds a set pressure to reduce the pressure to below the set pressure, a spillway pipe 15 that transfers excess high-pressure water equivalent to the amount of high-pressure water that exceeds the set pressure to a spillway outlet 15a, an intake pipe 16 that transfers water from the intake port 16a to the intake block 9, and a discharge pipe 17 that transfers high-pressure water from the discharge block 10 to a discharge port 17a.

[0050] A drive gear 1a is provided on the outer periphery of the drive shaft 1, and meshes with a driven gear 2a provided on the outer periphery of the crankshaft 2. Therefore, when rotational power from the engine body 30 is input to the drive shaft 1, the drive shaft 1 rotates and the crankshaft 2 is rotationally driven by the drive shaft 1. The drive shaft 1 and the crankshaft 2 are rotatably supported by bearings 1b and 2b, respectively, fixed to the crankshaft case 18.

[0051] As the crankshaft 2 rotates, the connecting rod 3 that links the crankshaft 2 and the crosshead 4 causes the crosshead 4 to reciprocate along the longitudinal direction (horizontal direction) inside the cylindrical portion 18a of the crankshaft case 18. As a result, the plunger 5 that is integrated with the crosshead 4 along the longitudinal direction (horizontal direction) reciprocates inside the packing case 6 along the longitudinal direction (horizontal direction).

[0052] When the plunger 5 is displaced upward in the figure, negative pressure is created inside the common block 8, which causes the suction valve 11 to open and the discharge valve 12 to close as it is pushed by a spring (not shown), and the water in the suction block 9 is drawn into the internal space surrounded by the plunger 5, packing case 6, packing 7, and common block 8.

[0053] The water taken into the internal space is pressurized as the plunger 5 moves up and down in the figure, becoming high-pressure water, which closes the suction valve 11 and opens the discharge valve 12, causing the high-pressure water to pass through the discharge block 10, safety valve 14, and discharge pipe 17 and be discharged to the outside from the discharge port 17a. Adjacent plungers 5 reciprocate inside the packing case 6 with a phase difference of 120°. Therefore, the time series value of the discharge flow rate of high-pressure water approximates a shape formed by combining three half-sine waves with a phase difference of 120°.

[0054] Normally, the discharge pressure of the high-pressure water is set to be smaller than the pressing force (set pressure) determined by the elastic force of spring 14a of safety valve 14. Therefore, communication between safety valve 14 and spillway pipe 15 is closed by piston 14b. When the discharge pressure of the high-pressure water exceeds the set pressure, the high-pressure water compresses spring 14a and lifts piston 14b. This allows communication between safety valve 14 and spillway pipe 15.

[0055] Then, until the discharge pressure of the high-pressure water falls below the set pressure determined by the elastic force of spring 14a, excess high-pressure water equivalent to the excess pressure is discharged to the outside through spillway 15, and when the discharge pressure of the high-pressure water becomes equal to the set pressure, spillway 15 is closed by piston 14b.

[0056] A filter 16b is provided in the suction pipe 16 that connects the suction block 9 and the suction port 16a. The filter 16b removes substances that may interfere with the reciprocating motion of the plunger 5, such as dust, pebbles, sand, gravel, and clay, contained in the water.

[0057] An air vent pipe 19 is provided between the discharge pipe 17 and the spillway pipe 15. This air vent pipe 19 is used to make the internal space surrounded by the suction pipe 16, discharge pipe 17, common block 8, suction block 9, discharge block 10, plunger 5, packing case 6, packing 7, and common block 8 liquid-tight. With the discharge outlet 17a installed as shown in Figure 14, a spillway line (not shown) is connected to the spillway outlet 15a, and the manual valve 19a of the air vent pipe 19 is opened to suck water from the suction port 16a and discharge high-pressure water from the spillway outlet 15a, thereby venting the air accumulated in the liquid piping to the outside together with the high-pressure water.

[0058] The engine body 30 is equipped with a combustion section 31 that compresses and burns fuel, and uses the combustion energy to move a piston (not shown) up and down in a reciprocating motion; an engine crankshaft 32 that converts the reciprocating motion of the piston (not shown) into rotational energy; an engine output shaft 33 that outputs the rotational energy of the engine crankshaft 32 to the outside as rotational power; a clutch 34 that directly connects the engine crankshaft 32 and the engine output shaft 33 to synchronize their rotation; a filter 35 that purifies the air; an intake manifold 36 that temporarily stores the clean air that has passed through the filter 35; an exhaust manifold 37 that temporarily stores the combustion gas; a catalyst 38 that purifies the combustion gas that is exhausted to the atmosphere; and a supercharger 39 that uses the energy of the exhaust combustion gas to generate highly concentrated compressed air.

[0059] The combustion unit 31 uses diesel fuel and burns the fuel by spontaneous ignition. Therefore, it does not have an igniter. The engine speed (the speed of the engine crankshaft 32) is controlled by the amount of fuel injected.

[0060] The engine output shaft 33 is connected to the engine crankshaft 32 via a clutch 34. Therefore, when the clutch 34 is engaged, the rotation speed of the engine output shaft 33 and the rotation speed of the engine crankshaft 32 are equal. Note that because the drive shaft 1 of the plunger pump main body 20 is directly connected to the engine output shaft 33 by a shaft coupling, the rotation speed of the drive shaft 1 is equal to the rotation speed of the engine output shaft 33, but the rotation speed of the crankshaft 2 of the plunger pump main body 20 is equal to the rotation speed of the engine output shaft 33 multiplied by the reduction ratio (= number of teeth of drive gear 1a / number of teeth of driven gear 2a). It is also possible to connect the drive shaft 1 of the plunger pump main body 20 and the engine output shaft 33 using a pair of pulley devices with the same diameter instead of the shaft coupling.

[0061] The clutch 34 is, for example, a wet multi-plate clutch. When hydraulic oil (oil) flows into the oil chamber of the clutch 34, the piston moves forward, pressing the friction discs together and connecting the engine crankshaft 32 to the engine output shaft 33. The hydraulic oil (oil) is supplied from a hydraulic pressure supply unit 40.

[0062] The hydraulic supply unit 40 supplies hydraulic oil to the engine body 30, the clutch 34, etc. via an oil pump, and the hydraulic oil is returned to an oil tank. The returned oil in the oil tank is cooled by air via an oil cooler.

[0063] The fuel supply unit 50 supplies fuel pressurized to a high pressure by a fuel pump to injectors arranged in the intake pipe, where it mixes with air to generate an air-fuel mixture. Each air-fuel mixture is supplied to each cylinder of the combustion unit 31 via each intake valve, where it is compressed by the piston and combusted.

[0064] The cooling water supply unit 60 uses a water pump to circulate cooling water through the engine block and the engine head cover, thereby cooling the engine block and the engine head cover, which have become hot due to the combustion of the air-fuel mixture.

[0065] The pump control unit 70 receives measurement signals relating to the discharge pressure of the plunger pump main body 20 (measurement value of the pressure sensor 13), the rotation speed of the engine main body 30 (rotation speed of the engine crankshaft 32), and the remaining amount of fuel in the fuel tank, and transmits a command value for the rotation speed of the engine main body 30 to the engine control unit 90 to control the pump in order to change the discharge pressure and discharge flow rate of the plunger pump main body 20.

[0066] The engine control unit 90 receives measurement signals relating to the rotation speed of the engine body 30, the fuel injection amount, the intake air amount, the combustion pressure, and the combustion temperature, and controls the rotation speed of the engine body 30 so that it is equal to a command value.

[0067] Fig. 2 is a cross-sectional explanatory view of a main part showing the operation mode switching unit 80 of the high-pressure water jet pump according to the present invention. For convenience of explanation, Fig. 2 shows the operation mode in the low-pressure mode when the electromagnetic on-off valve 82 is open. This "low-pressure mode" is an operation mode of the high-pressure water jet pump 100 in which the discharge pressure and discharge flow rate in the normal operation mode (high-pressure mode) are uniformly reduced to desired levels. Details of the low-pressure mode will be described later with reference to Figs. 5 and 6.

[0068] The operation mode switching unit 80 selectively switches between low pressure mode and high pressure mode by opening and closing the electromagnetic on-off valve 82. In the high pressure mode, all of the high pressure water flowing through the discharge pipe 17 flows and is discharged to the outside from the discharge port 17a. On the other hand, the high pressure water discharged from the discharge block 10, excluding the "high pressure water flowing through the bypass pipe 81", is discharged to the outside from the discharge port 17a.

[0069] The operation mode switching unit 80 includes a bypass pipe 81 that connects a portion of the high-pressure water flowing through the discharge pipe 17 to the spillway pipe 15, an electromagnetic valve 82 that controls the flow in the bypass pipe 81, a high-pressure water jet spraying unit 83 that sprays the high-pressure water flowing through the bypass pipe 81 in the form of a jet water stream JW, and a jet water stream collision unit 84 that causes the jet water stream JW to collide with a cylindrical wall surface 84ab, causing the jet water stream JW to "repeatedly reflect at the cylindrical wall surface 84ab" and "concentrated multiple collisions near the central axis C," thereby stably and quickly dissipating the energy (head) of the jet water stream JW. Note that the "jet water stream JW" here refers to a high-speed water stream that can be considered as a bundle of streamlines that are symmetrical about the injector central axis 83aC (FIG. 4) and form a predetermined angle δ. Each component is described in more detail below.

[0070] The bypass pipe 81 is formed, for example, by a combination of metal piping and flexible piping, but may be formed only of metal piping or only of flexible piping. The inner diameter φD1 of the bypass pipe 81 is smaller than the inner diameter φD4 of the discharge pipe 17 and the inner diameter φD3 of the spillway pipe 15. For example, φD4 = φD3 = 2 × φD1. Therefore, the flow path cross-sectional area of ​​the bypass pipe 81 is 1 / 4 the flow path cross-sectional area of ​​the discharge pipe 17 or the spillway pipe 15.

[0071] The electromagnetic on-off valve 82 is an on / off valve that is electromagnetically driven by, for example, a solenoid. When the electromagnetic on-off valve 82 is turned on, the bypass pipe 81 is opened and a portion of the high-pressure water flowing through the discharge pipe 17 is sprayed from the high-pressure water jet spraying section 83 onto the cylindrical wall surface 84ab of the jet water stream collision section 84. On the other hand, when the electromagnetic on-off valve 82 is turned off, the bypass pipe 81 is blocked and all of the high-pressure water pumped from the discharge block 10 flows through the discharge pipe 17 and is discharged to the outside from the discharge port 17a.

[0072] The electromagnetic on-off valve 82 is not limited to an off / off valve, but may be any valve, such as a needle valve whose opening is adjustable. Also, in addition to electromagnetically driven solenoid valves, manual valves may also be used.

[0073] The high-pressure water jet spraying unit 83 is configured, for example, by an injector 83a (FIG. 3) having an orifice, and sprays the high-pressure water flowing through the bypass pipe 81 in the form of a jet water stream JW. The nozzle of the high-pressure water jet spraying unit 83 is inserted into the inside of the jet water stream collision unit 84. In addition, to facilitate replacement of the injector 83a (FIG. 3), the high-pressure water jet spraying unit 83 is threadedly coupled to the jet water stream collision unit 84. Details of the high-pressure water jet spraying unit 83 will be described later with reference to FIG. 3.

[0074] The jet water stream collision section 84 is configured, for example, by a T-joint 84a (FIG. 3) having a cylindrical wall surface 84ab. The jet water stream JW sprayed from the high-pressure water jet spraying section 83 is repeatedly reflected by the cylindrical wall surface 84ab, and the reflected jet water streams JW collide with each other multiple times, thereby steadily and quickly dissipating the energy (head) of the jet water stream JW and calming it to the point where it can no longer be reflected. The calmed jet water stream JW flows through the overflow pipe 15 as overflow water and is discharged to the outside through the overflow outlet 15a and returned to a water tank (not shown). Details of the jet water stream collision section 84 will be described later with reference to FIG. 3.

[0075] Fig. 3 is an explanatory diagram showing the high-pressure water jet spraying unit 83 and the jet water stream collision unit 84. Fig. 3(a) shows a front view of the high-pressure water jet spraying unit 83 and the jet water stream collision unit 84, and Fig. 3(b) is a cross-sectional view of Fig. 3(a). 3(a), the high-pressure water jet spraying section 83 is configured to include an injector 83a that sprays water in the form of a jet water stream JW, an injector threaded joint 83b that stably supports the injector 83a and is used to position the injector 83a inside the jet water stream collision section 83, and a bypass pipe joint 83c that connects the bypass pipe 81 to the injector threaded joint 83b. Each component part is made of an iron-based metal such as stainless steel.

[0076] As shown in Figure 3(b), the injector 83a has an upper male thread 83aa that is threadedly connected to a lower female thread 83ba of the injector threaded fitting 83b. The injector threaded fitting 83b has a lower male thread 83bb on its lower outer periphery and an upper female thread 83bc on its upper inner periphery. The lower male thread 83bb is threadedly connected to a female thread 84aa of the T-type fitting 84a, and the upper female thread 83bc is threadedly connected to a male thread 83ca of the bypass pipe fitting 83c.

[0077] 3(a), the jet water stream collision section 84 is composed of a T-shaped joint 84a against which the jet water stream JW ejected from the injector 83a collides, a spillway pipe inlet joint 84b for connecting the upstream part of the spillway pipe 15, and a spillway pipe outlet joint 84c for connecting the downstream part of the spillway pipe 15. Each component is made of an iron-based metal such as stainless steel.

[0078] 3(b), the T-joint 84a has a female thread 84aa at the intersection, which is threadedly connected to the lower male thread 83bb of the injector threading joint 83b. The T-joint 84a also has a first female thread 84ad and a second female thread 84ac in the straight pipe portion, with the first female thread 84ad threadedly connected to the male thread 84ba of the spillway pipe inlet joint 84b and the second female thread 84ac threadedly connected to the male thread 84ca of the spillway pipe outlet joint 84c.

[0079] As described above, the high-pressure water jet spraying unit 83 and the jet water stream collision unit 84 are connected to each other by screws, which makes it easy to replace and clean the parts.

[0080] The inner diameter of the cylindrical wall surface 84ab of the T-joint 84a is equal to the inner diameter φD3 of the spillway pipe 15. This is larger than the outlet diameter φD2 of the injector 83a. Therefore, the jet water flow JW injected from the injector 83a is repeatedly reflected by the cylindrical wall surface 84ab, and the reflected water flows collide with each other multiple times.

[0081] 4 is a schematic explanatory diagram showing repeated reflections and multiple collisions of the jet water stream JW ejected from the injector 83a on the cylindrical wall surface 84ab. As shown in FIG. 4(b), the jet water stream JW ejected from the injector 83a can be considered as a two-dimensional, fan-shaped (three-dimensional, cone-shaped) streamline bundle consisting of numerous streamlines that form a predetermined angle with respect to the injector central axis 83aC. For ease of understanding, only the repeated reflections and multiple collisions on the cylindrical wall surface 84ab of the left-end jet water stream JWL and the right-end jet water stream JWR, which are located at the outermost positions when viewed from the central axis C, are shown. The repeated reflections and multiple collisions of the other streamlines between them are not shown.

[0082] As shown in Figure 4(a), the left-end jet water stream JWL, represented by the solid line, is emitted from the injector 83a and reflects off the cylindrical wall surface 84ab along the path of reflection points P1 → P2 → P3 → P4 → .... Reflection at reflection point P1 occurs along tangent line L1, and the normal to tangent line L1 coincides with the radius r of the cylindrical wall surface 84ab. In addition, triangle C·P1·P2 is an isosceles triangle with two equal sides. As a result, ∠C·P1·P2 = ∠P1·P2·C, and the reflection angle at reflection point P1 and the incident angle at reflection point P2 are equal. This means that the left-end jet water stream JWL, which enters at an incident angle θ relative to the radius r, exits at a reflection angle θ relative to the radius r, and then enters the next reflection point at an incident angle θ relative to the radius r and exits at a reflection angle θ, repeating this process. The same applies to the right-end jet water stream JWR, represented by the dashed-dotted line. Furthermore, the same applies to the other jet water flows sandwiched between the leftmost jet water flow JWL and the rightmost jet water flow JWR in Figure 4(b).

[0083] The above can be seen as if the jet water stream at each reflection point were an injection port, ejected toward the central axis C at an injection angle twice the angle of incidence (e.g., 2θ). As a result, the jet water streams from each reflection point collide multiple times within the area surrounding the central axis C (represented by the dotted line). As a result, the jet water stream JW ejected from the injector 83a loses its energy (head) through "repeated reflections on the cylindrical wall surface 84ab" and "multiple collisions within the area surrounding the central axis C." The jet water stream JW eventually calms down to the point where it can no longer be reflected, becoming spillwater with a pressure lower than that of the high-pressure water, and is returned to the water tank or water source through the spillway 15 and spillway outlet 15a (Figure 2).

[0084] The above facts indicate that by directing a portion of the high-pressure water flowing through the discharge pipe 17 (FIG. 2) into the bypass pipe 81 and spraying it from the injector 83a in the form of a jet water stream JW, which then collides with the cylindrical wall surface 84ab, a portion of the high-pressure water flowing through the discharge pipe 17 (FIG. 2) can be continuously and stably extracted. This indicates that the discharge flow rate and discharge pressure of the high-pressure water flowing through the discharge pipe 17 (FIG. 2), which are determined by the engine speed, can be continuously and stably reduced across the engine speed range by spraying the high-pressure water in the form of a jet water stream JW from the injector 83a and causing it to collide with the cylindrical wall surface 84ab. In other words, by spraying the high-pressure water in the form of a jet water stream JW from the injector 83a and causing it to collide with the cylindrical wall surface 84ab, a new operating mode (low-pressure mode) shifted to a lower pressure than the normal operating mode can be created. This low-pressure mode is described below.

[0085] Fig. 5(a) is a graph showing an example of the correlation characteristic between "engine rotation speed and the discharge pressure of the plunger pump main body 20 at that rotation speed" of the high-pressure water jet pump 100 according to the present invention. Fig. 5(b) is a graph showing an example of the correlation characteristic between "engine rotation speed and the discharge flow rate of the plunger pump main body 20 at that rotation speed". The horizontal axis represents engine rotation speed (rpm), and the vertical axis represents discharge pressure (MPa) and discharge flow rate (L / min), respectively. "Pn" in Fig. 5(a) represents the maximum normal discharge pressure (MPa), and "Fn" in Fig. 5(b) represents the maximum normal discharge flow rate (L / min).

[0086] As shown in Figure 5(a), for example, by selecting the outlet diameter φD2 (mm) of the injector 83a (Figure 3(b)) so that the discharge pressure becomes the normal maximum discharge pressure Pn (MPa) when the engine speed is 1700 (rpm), the high-pressure mode is reduced and a new mode (low-pressure mode) is created in which the discharge pressure continuously increases from the normal minimum discharge pressure Pn-5 (MPa) to the normal maximum discharge pressure Pn (MPa). This Pn-5 (MPa) is a discharge pressure that cannot be set in the high-pressure mode. In this case, it is desirable that the inner diameter φD1 of the bypass pipe 81 (Figure 3(b)) be smaller than the inner diameter φD3 of the spillway pipe 15 (Figure 3(b)).

[0087] The normal pressure range in the low pressure mode is expanded downward compared to the normal pressure range in the high pressure mode.

[0088] As shown in Figure 5(b), the discharge flow rate in low-pressure mode also increases continuously from the normal minimum discharge flow rate Fn-75 (L / min) to the normal maximum discharge flow rate Fn (L / min) in proportion to the engine speed. In particular, at an idling speed of 1100 rpm, the discharge flow rate decreases from Fn-43 (L / min) to Fn-75 (L / min). This Fn-75 (L / min) is a discharge flow rate that cannot be set in high-pressure mode.

[0089] The normal flow rate range in the low pressure mode is expanded downward compared to the normal flow rate range in the high pressure mode.

[0090] FIG. 6 is a graph showing an example of the correlation characteristics between the discharge pressure and the discharge flow rate in the plunger pump body 20 of the high-pressure water jet pump 100 according to the present invention. Figure 6 is a combination of Figures 5(a) and 5(b), and shows that the normal range of discharge pressure and discharge flow rate in low-pressure mode is expanded downward compared to the normal range of discharge pressure and discharge flow rate in high-pressure mode.

[0091] As described above, the high-pressure water jet pump 100 according to one embodiment of the present invention has been described with reference to the drawings, but the embodiment of the present invention is not limited to the above. In other words, various modifications and changes can be made within the scope of the technical scope of the present invention. For example, with regard to the jet water stream collision section 84, which collides the jet water stream JW injected from the injector 83, the flow path cross-sectional area (πD2 2 / 4) larger than the cross-sectional area (πr 2 , L 2 7, it is also possible to use an L-shaped joint.

[0092] The electromagnetic on-off valve 82 only needs to have the function of blocking / passing the high-pressure water flowing through the bypass pipe 81. Therefore, as shown in Fig. 8, it is also possible to use a valve whose opening can be adjusted, such as a needle valve or a ball valve. In this case, by adjusting the opening of the needle valve, it is possible to create an intermediate pressure mode located between the high-pressure mode and the low-pressure mode, in which the high-pressure mode is reduced to a desired level.

[0093] In the above embodiment, the jet water stream JW injected from the injector 83a is caused to collide with the cylindrical wall surface 84ab, but it is also possible to cause the jet water stream JW to collide with a wall surface other than the cylindrical wall surface 84ab, for example, with a flat wall surface 84ab'. An example in which the jet water stream JW is caused to collide with the flat wall surface 84ab' is shown below.

[0094] FIG. 9 is an explanatory diagram showing a box-shaped joint 84a" that causes the jet water flow JW to collide with a flat wall surface 84ab'. For convenience of explanation, only the left end jet water flow JWL is shown among the jet water flows JW ejected from the injector 83a. This box-shaped joint 84a" is a substitute for the T-shaped joint 84a (Fig. 3) that constitutes the jet water flow collision section 84. Therefore, the spillway pipe inlet joint 84b (Fig. 3) and the spillway pipe outlet joint 84c (Fig. 3) are screwed into the box-shaped joint 84a" along the central axis C' of the box-shaped joint 84a". In addition, the flow path cross-sectional area (L 2 ) is the cross-sectional area of ​​the outlet of the injector (83a) (πD2 2 / 4).

[0095] Regarding reflection from the flat wall surface 84ab', the left-end jet water stream JWL, which is ejected from the injector 83a at an ejection angle δ, is incident on the bottom and top of the flat wall surface 84ab' at an incident angle δ equal to the ejection angle δ, and is reflected at the same reflection angle δ. On the other hand, on the left and right sides of the flat wall surface 84ab', it is incident at an incident angle θ, which is 90° minus the ejection angle δ, and is reflected at the same reflection angle θ. The same applies to the right-end jet water stream JWR. Furthermore, multiple collisions between the jet water streams JW reflected from the flat wall surface 84ab' occur in the vicinity of the flat wall surface 84ab', away from the central axis C'.

[0096] In the above embodiment, the electromagnetic on-off valves 82 are all arranged upstream of the high-pressure water jet spraying section 83, but they may also be arranged downstream of the high-pressure water jet spraying section 83. An example in which the electromagnetic on-off valves 82 are arranged downstream of the high-pressure water jet spraying section 83 will be described below.

[0097] FIG. 10 is a cross-sectional explanatory view of a main part showing an operation mode switching unit 80′ in which the electromagnetic on-off valve 82 is arranged downstream of the high-pressure water jet spraying unit 83. The high-pressure water jet spraying section 83 is connected to the upper part of the bypass pipe 81 and is screwed into a jet water stream collision section 84' equipped with an L-shaped joint. The jet water stream collision section 84 is connected to the middle part of the bypass pipe 81, and an electromagnetic on-off valve 82 is connected to the middle part of the bypass pipe 81. The electromagnetic on-off valve 82 is connected to the lower part of the bypass pipe 81, and the lower part of the bypass pipe 81 is connected to the spillway pipe 15.

[0098] The high-pressure water flowing through the upper part of the bypass pipe 81 is sprayed in the form of a jet water stream JW from the high-pressure water jet spraying section 83. The jet water stream JW is repeatedly reflected by the cylindrical wall surface 84ab, and the reflected jet water streams JW collide with each other multiple times, thereby steadily and quickly dissipating the energy (head) of the jet water stream JW and calming it down to the point where it can no longer be reflected. The calmed jet water stream JW flows as overflow water through the middle part of the bypass pipe 81, flows through the electromagnetic on-off valve 82 → the lower part of the bypass pipe 81 → overflow pipe 15, and is discharged to the outside through the overflow outlet 15a and returned to the water tank (not shown).

[0099] At the start of the "high pressure mode" when the electromagnetic on-off valve 82 is closed, a very small amount of high-pressure water is sprayed in the form of a jet water stream JW for a very short period of time from the high-pressure water jet spraying unit 83. However, because the amount of water sprayed is very small, the effect on the discharge pressure and discharge flow rate of the high-pressure water discharged from the discharge port 17a is negligible, and the discharge pressure and discharge flow rate of the high-pressure water discharged from the discharge port 17a remain almost unchanged.

[0100] Furthermore, in the above-described operation mode switching units 80, 80', each component has its own individual function. For example, the electromagnetic on-off valve 82 has its own individual function of opening (passing) / closing (blocking) the high-pressure water flowing through the bypass pipe 81. Alternatively, each component can be made to have the functions of other components in addition to its own individual function. For example, the electromagnetic on-off valve 82' can be made to have the function of a high-pressure water jet spraying unit 83, or the spillway pipe 15 can be made to have the function of a jet water stream collision unit 84. In this case, the other component can be omitted. Below is an example of a component having the functions of other components.

[0101] FIG. 11 is an explanatory diagram showing an operation mode switching unit 80 ″ in which the function of a high-pressure water jet spraying unit 83 is provided to an electromagnetic on-off valve 82 ′. By adjusting the opening degree of the electromagnetic on-off valve 82', high-pressure water can be sprayed in the form of a jet water stream JW, so the electromagnetic on-off valve 82' is given the individual and unique function of the high-pressure water jet spraying unit 83. Therefore, it is possible to omit the high-pressure water jet spraying unit 83 from this operation mode switching unit 80".

[0102] 12, the jet water stream collision section 84 can also be installed so that the jet water stream JW ejected from the electromagnetic on-off valve 82' is parallel to the central axis C of the jet water stream collision section 84. In this case, the electromagnetic on-off valve 82' and the outlet of the spillway pipe 15 are connected to the straight section of the jet water stream collision section 84, and the inlet of the spillway pipe 15 is connected to the intersection section.

[0103] 13, the operation mode switching unit 80 can also be installed so that the jet water stream JW sprayed from the high-pressure water jet spraying unit 83 is parallel to the central axis C of the jet water stream collision unit 84. In this case, the high-pressure water jet spraying unit 83 and the outlet portion of the spillway pipe 15 are connected to the straight portion of the jet water stream collision unit 84, and the inlet portion of the spillway pipe 15 is connected to the intersection portion. [Explanation of symbols]

[0104] 1 drive shaft 1a drive gear 1b, 2b bearings 2 crankshaft 2a Driven gear 3 Connecting rod 4 Crosshead 5 plungers 6 Packing case 7. Packing 8 Common Blocks 9 Suction block 10 Discharge block 11 Suction valve 12 Discharge valve 13 Pressure Sensor 14 Safety valve 14a Spring 14b Piston 15 Spill pipe 15' merge pipe 15a Spill port 16 Suction pipe 16a Intake port 16b filter 17 Discharge pipe 17a Discharge port 18 Crankshaft case 18a Cylindrical part 19 Air vent pipe 19a Manual valve 20 Plunger pump body 30 Engine body 31 Combustion section 32 Engine crankshaft 33 Engine output shaft 34 Clutch 35 filters 36 Intake manifold 37 Exhaust manifold 38 Catalyst 39 Supercharger 40 Hydraulic supply unit 50 Fuel supply section 60 Cooling water supply section 70 Pump control section 80,80',80”,80A,80B Operation mode switching section 81 Bypass pipe 82,82' Solenoid valve 83 High-pressure water jet injection unit 83a injector 83aa Male thread 83aC Injector center axis 83b Injector threaded fitting 83ba Lower female thread 83bb Lower male thread 83bc upper female thread 83c Bypass pipe fitting 83ca male thread 84,84' Jet water flow collision section 84a T-joint 84a' L-shaped joint 84a" box joint 84aa female thread 84ab Cylindrical wall 84ab' flat wall 84ac second female thread 84ad First male thread 84b Spillway pipe inlet joint 84ba male thread 84c Spill pipe outlet fitting 84ca male thread 90 Engine control unit 100 High-pressure water jet pump C Central axis of the cylindrical wall C' Central axis of the plane wall JW Jet Water Stream JWL Left end jet water flow JWR Right-end jet stream δ injection angle θ Incident angle, reflection angle P1, P2, P3, P4 Leftmost jet water flow reflection point P1', P2', P3', P4' Right end jet water flow reflection points φD1 Inner diameter of bypass pipe φD2 Injector outlet diameter φD3 Inner diameter of spillway pipe φD4 Inner diameter of discharge pipe L1,L2,L3,L4 Tangent line L1',L2',L3',L4' Tangent line r Radius of the cross section of the cylindrical wall L: Length of one side of the cross section of the plane wall Pn Maximum normal discharge pressure Fn Normal maximum discharge flow rate

Claims

1. A plunger (5) that generates high-pressure water to increase the pressure of the sucked water and make it easier for the pile material to penetrate into the ground; a safety valve (14) that releases excess high-pressure water equivalent to the excess pressure when the pressure of the high-pressure water exceeds a set pressure, thereby reducing the pressure of the high-pressure water to below the set pressure; a discharge port (17a) for discharging the high-pressure water to the outside; a discharge pipe (17) for transferring the high-pressure water from the safety valve (14) to the discharge port (17a); an overflow port (15a) for discharging excess water corresponding to the excess high-pressure water to the outside; a spillway (15) for transferring the spillway water from the safety valve (14) to the spillway outlet (15a); A high-pressure water jet pump (100) comprising an engine body (30) that supplies power to the plunger (5), The discharge pipe (17) is connected to a bypass pipe (81) that directly or indirectly communicates with the spillway pipe (15), and the bypass pipe (81) crosses the discharge pipe (17). The bypass pipe (81) has an on-off valve (82) that passes / blocks the high-pressure water; a high-pressure water jet spraying section (83) that sprays the high-pressure water in the form of a jet water stream (JW) by means of an injector (83a) "having a portion whose inner diameter is reduced to be smaller than the inner diameter (φD1) of the bypass pipe (81)"; The high-pressure water jet spraying unit (83) has a flow path cross-sectional area (πD2 ２ / 4) ２ , L ２ ) are connected to the jet water impingement sections (84, 84') having wall surfaces (84ab, 84ab') A high-pressure water jet pump characterized by:

2. 2. The high-pressure water jet pump according to claim 1, The jet water flow collision section (84) has a T-shaped joint (84a), and the spillway pipe (15) is connected to the straight pipe portions (84b, 84c) of the T-shaped joint (84a). A high-pressure water jet pump characterized by:

3. 2. The high-pressure water jet pump according to claim 1, The jet water stream collision section (84') has an L-shaped joint, and the other port of the L-shaped joint to which the high-pressure water jet injection section (83) is not connected is connected to a confluence pipe (15') that flows low-pressure water "calmed by repeated reflections of the jet water stream (JW) on the wall surfaces (84ab, 84ab')" into the spillway pipe (15). A high-pressure water jet pump characterized by:

4. 2. The high-pressure water jet pump according to claim 1, The high-pressure water jet spraying section (83) is composed of an injector (83a) that sprays a jet water flow, an injector screw-in joint (83b) that has a male thread portion (83bb) on the lower outer periphery and a female thread portion (83bc) on the upper inner periphery for disposing the injector (83a) inside the jet water flow collision section (84), and a bypass pipe joint (83c) that has a male thread portion (83ca) on the lower outer periphery for connecting the bypass pipe (81) to the injector screw-in joint (83b). A high-pressure water jet pump characterized by:

5. 2. The high-pressure water jet pump according to claim 1, The on-off valve (82) is an electromagnetic valve that can be opened and closed by an electric signal. A high-pressure water jet pump characterized by:

6. 2. The high-pressure water jet pump according to claim 1, The opening degree of the on-off valve (82) is variable. A high-pressure water jet pump characterized by:

7. 2. The high-pressure water jet pump according to claim 1, The overflow water discharged from the overflow outlet (15a) is configured to be returned to the water source or water tank. A high-pressure water jet pump characterized by:

8. 2. The high-pressure water jet pump according to claim 1, The on-off valve (82) is configured to inject the high-pressure water in the form of a jet water flow (JW), and the high-pressure water jet injecting unit (83) is omitted. A high-pressure water jet pump characterized by:

9. 2. The high-pressure water jet pump according to claim 1, The jet water stream collision portion (84) is attached so that the jet water stream (JW) is parallel to the central axis (C) in the longitudinal direction of the jet water stream collision portion (84). A high-pressure water jet pump characterized by:

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