JP6497996B2 - Water jet propulsion machine - Google Patents

Description

  The present invention relates to a water jet propulsion device.

  In general, a water jet propulsion device is known in which water sucked from the bottom of a ship is guided to a pump through a suction casing, and water pressurized by the pump is jetted behind the stern to propel the ship. Conventionally, this type of water jet propulsion device is known to have an axial flow type impeller (impeller) as a pump shape (see, for example, Patent Document 1). In general, an axial flow type pump accommodates an outer diameter of an impeller, that is, an impeller, when equivalent performance is required as compared with a mixed flow type pump having a mixed flow type impeller (impeller). Since the outer diameter (installation diameter) of the pump casing is smaller than that of the mixed flow type, there is an advantage that the installation space on the hull can be reduced.

JP 2002-225796 A

  By the way, in recent years, for the purpose of further reducing the installation space, there has been a demand for reducing the pipe diameter of the suction casing attached to the water intake on the ship bottom. However, when the pipe diameter of the suction casing is reduced, the pipe diameter of the pump casing connected to the outlet portion of the suction casing is reduced, so that the outer diameter of the impeller accommodated in the pump casing is inevitably reduced. For this reason, there was a concern about the deterioration of the performance due to the small size of the pump.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a water jet propulsion device that can realize downsizing of the suction casing without reducing the performance of the pump.

  In order to solve the above-described problems and achieve the object, the present invention provides a suction casing that is attached to a water intake at the bottom of a ship, a pump casing that is connected to an outlet portion of the suction casing, and a rotation that is disposed in the pump casing. A water jet propulsion device having an axial flow type impeller that rotates around an axis and propelling the ship by injecting water pressurized by the impeller to the rear of the stern, wherein the pump casing is an outlet of the suction casing A cylindrical main body having a larger pipe diameter than the part, and a reduced diameter part that gradually decreases from the pipe diameter of the main body part to the pipe diameter of the outlet portion of the suction casing on the upstream side of the front edge of the impeller, It is provided with.

  According to this configuration, the pump casing includes a cylindrical main body portion having a pipe diameter larger than the outlet portion of the suction casing, and an outlet portion of the suction casing from the pipe diameter of the main body portion on the upstream side of the front edge of the impeller. Therefore, it is possible to connect the pump casing to the outlet portion of the suction casing having a small pipe diameter without reducing the outer diameter of the impeller. Accordingly, the suction casing can be reduced in size without reducing the performance of the pump, and the installation space of the water jet propulsion device can be reduced. Furthermore, since the amount of water held in the suction casing is reduced, the hull weight during operation can be reduced.

  In this configuration, the reduced diameter portion may be formed concentrically around the main body portion and the rotation axis. According to this configuration, the pump casing can be created more easily, and the suction casing can be downsized with a simple configuration.

  In addition, the diameter-reduced portion has the center of the outlet portion with respect to the center of the main body portion so that the bottom surface of the outlet portion and the bottom surface of the main body portion are at the same height. It may be eccentric vertically downward. According to this configuration, by changing the cross-sectional area ratio of the upper and lower spaces in the reduced diameter portion with respect to the rotation axis, the difference in the flow rate flowing up and down can be suppressed, and the flow rate balance can be equalized.

  Further, the amount of eccentricity between the pipe center of the outlet and the pipe center of the main body relative to the pipe diameter of the main body may be 10% or less. According to this configuration, the flow rate balance of the water flowing through the pump casing can be suitably adjusted, and the inflow into the pump casing can be made uniform.

  Moreover, the raising / lowering part which raises / lowers the main-body part of a pump casing is provided, and a diameter reducing part is good also as a structure which follows the raising / lowering of a main-body part, and decenters. According to this configuration, rectification can be realized by dynamically adjusting the amount of eccentricity of the reduced diameter portion and suppressing a difference in flow rate flowing up and down in the pump casing.

  The reduced diameter portion includes a plurality of annular members arranged so that the pipe diameter is gradually reduced from the main body portion toward the outlet portion, and a seal member that seals between adjacent annular members. Also good. According to this configuration, the eccentric amount of the reduced diameter portion can be easily adjusted by displacing the center position of each annular member.

  According to the present invention, the pump casing includes a cylindrical main body portion having a pipe diameter larger than the outlet portion of the suction casing, and an outlet portion of the suction casing from the pipe diameter of the main body portion on the upstream side of the front edge of the impeller. Therefore, the suction casing can be downsized without reducing the performance of the pump.

FIG. 1 is a schematic cross-sectional view of a water jet propulsion device according to a first embodiment. FIG. 2 is a schematic cross-sectional view of a water jet propulsion device according to the second embodiment. FIG. 3 is a partial cross-sectional view of the reduced diameter portion viewed from the axial direction. FIG. 4 is a schematic cross-sectional view of the water jet propulsion device according to the third embodiment. FIG. 5 is a schematic cross-sectional view showing the configuration of the reduced diameter portion. FIG. 6 is a schematic cross-sectional view showing a state after the reduced diameter portion is eccentric. FIG. 7 is a schematic cross-sectional view showing the water jet propulsion device after the reduced diameter portion is eccentric.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, the constituent elements in the embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined, and when there are a plurality of embodiments, the embodiments can be combined.

[First Embodiment]
FIG. 1 is a schematic cross-sectional view of a water jet propulsion device according to a first embodiment. As shown in FIG. 1, the water jet propulsion device 10 includes a suction casing 11 attached to a water intake 2 </ b> A formed in the ship bottom 2, a pump casing 12 connected to the suction casing 11, and a connection to the pump casing 12. The discharge casing 13 is provided. The discharge casing 13 is fixed to a drain outlet 3A formed in the stern 3. These casings 11 to 13 connect the ship bottom 2 and the stern 3 of the ship to form a piping 14 through which water for propulsion flows.

  The suction casing 11 has a curved pipe shape. The suction port 11A opens toward the water intake port 2A on the bottom 2 of the ship, and after rising upward and tilting from the water intake port 2A, the discharge port (exit part) 11B is stern. Open toward 3. A strainer (not shown) is attached in the vicinity of the suction port 11 </ b> A in the suction casing 11 so that underwater foreign matter sucked from the suction port 11 </ b> A does not flow into the piping 14.

  An inlet 12A of the pump casing 12 is flange-connected to the discharge port 11B of the suction casing 11, and an axial flow type impeller (impeller) 15 is rotatably accommodated inside the pump casing 12. The impeller 15 includes a cone portion 16 having a substantially conical shape, and a plurality of guide blades 17 fixed to the outer peripheral surface of the cone portion 16. A rotating shaft 18 that rotates the impeller 15 is connected to the tip of the cone portion 16. The rotary shaft 18 is drawn to the outside through a drawer pipe 11 </ b> C provided in the suction casing 11, and the distal end side of the rotary shaft 18 is connected to an engine (drive source) 19.

  An inlet 13 </ b> A of the discharge casing 13 is flange-connected to the outlet 12 </ b> B of the pump casing 12, and guide vanes 20 are fixed to the inner surface of the discharge casing 13. The guide vane 20 is a stationary blade that straightens the flow without reducing the flow rate of the water pressurized by the impeller 15. An outlet 13 </ b> B of the discharge casing 13 is fixed to a drain port 3 </ b> A formed in the stern 3.

  In the configuration described above, when the engine 19 is driven to rotate the impeller 15, water is sucked into the suction casing 11 from the water intake port 2 </ b> A formed in the ship bottom 2 along with this rotation. This water is pressurized by the impeller 15, then rectified by the guide vanes 20, and sprayed to the rear of the stern through the drain port 3 </ b> A. The ship can be propelled by the propulsion of the water jet sprayed out of the ship.

  By the way, in this kind of water jet propulsion machine, reduction of the installation space to a ship is desired. On the other hand, when each casing constituting the water jet propulsion unit is simply reduced in size, the outer diameter of the impeller accommodated in the pump casing is reduced. Since the outer diameter of the impeller is closely related to the propulsive force of the ship, there was a concern that the propulsion performance would decrease with downsizing.

  In this embodiment, the pump casing 12 is provided on the upstream side of the main body portion 21 formed in a cylindrical shape and the main body portion 21, and is gradually reduced toward the discharge port 11 </ b> B of the suction casing 11. And a diameter portion 22. The main body 21 is formed with a pipe diameter D2 larger than the pipe diameter D1 of the discharge port 11B of the suction casing 11, and the impeller 15 is accommodated inside the main body 21. Further, the reduced diameter portion 22 is provided on the upstream side of the front edge 17A of the guide vane 17 of the impeller 15 and is reduced in diameter from the pipeline diameter D2 of the main body portion 21 to the pipeline diameter D1 of the discharge port 11B.

  According to this configuration, the pump casing 12 includes the reduced diameter portion 22 that gradually reduces the pipe diameter toward the discharge port 11 </ b> B of the intake casing 11, so that the suction casing 11 connected to the reduced diameter portion 22 discharges. The pipe diameter D1 of the outlet 11B can be reduced, and as a result, the suction casing 11 can be reduced in size. According to the inventor's experiments and simulations, it has been found that the volume of the suction casing 11 can be reduced by 10 to 20% compared to the prior art. Thus, by reducing the size of the suction casing 11, it is possible to reduce the manufacturing cost of the suction casing 11 and to reduce the installation space on the ship. In addition, since the amount of water retained in the suction casing 11 is reduced, the weight of the hull during operation can be reduced.

  Further, the main body 21 of the pump casing 12 is formed to have a pipe diameter D2 larger than the pipe diameter D1 of the discharge port 11B of the suction casing 11, so that the outer diameter of the impeller 15 is reduced as the suction casing 11 is downsized. There is no need to convert Accordingly, it is possible to prevent the impeller 15 (pump) from supplying water, that is, to reduce the propulsion power of the ship, while realizing the suction casing 11. Furthermore, since the reduced diameter portion 22 is provided on the upstream side of the front edge 17A of the guide vane 17 of the impeller 15, the guide vane 17 of the impeller 15 does not contact the reduced diameter portion 22.

  Further, by using the pump casing 12 of the present embodiment, the impeller 15 having the same outer diameter can be used for the suction casing 11 having different pipe diameters, so that the manufacturing cost of the impeller 15 (pump) is reduced. Can be achieved.

  In the present embodiment, the pump casing 12 has a main body portion 21 and a reduced diameter portion 22 formed concentrically. Specifically, both the main body 21 and the reduced diameter portion 22 are formed concentrically around the axis of the rotating shaft 18. In this configuration, the pump casing 12 can be created more easily, and the suction casing 11 can be downsized with a simple configuration. Further, the rotation shaft of the impeller 15 can be easily attached to the rotation shaft 18 disposed on the central axis of the suction casing 11.

  Here, the shape of the reduced diameter portion 22 is determined by the ratio of the pipe area before and after the diameter reduction (the pipe diameter) and the expansion angle θ. In this case, the enlarged angle θ is preferably set to an angle that does not allow the entire length of the pump casing 12 to be longer than that of the previous pump casing. Furthermore, since the pipe area rapidly increases as the enlargement angle θ is increased, the main flow in the pipe 14 may be peeled off. For this reason, in order to suppress generation | occurrence | production of peeling effectively, it is preferable to set the magnitude | size of the expansion angle (theta) to 20 degrees or less.

[Second Embodiment]
Next, the water jet propulsion device 110 according to the second embodiment will be described. FIG. 2 is a schematic cross-sectional view of the water jet propulsion device according to the second embodiment, and FIG. 3 is a partial cross-sectional view of the reduced diameter portion viewed from the axial direction. In addition, the same code | symbol is attached | subjected to the same component as 1st Embodiment, and detailed description is abbreviate | omitted. In the second embodiment, the basic configuration is the first embodiment, and the shape of the pump casing 112 is different from that of the first embodiment.

  In the piping 14 configured to draw water from the water intake 2 </ b> A formed in the ship bottom 2 as in this configuration, the flow rate balance of the water flowing through the piping 14 is disrupted, and the flow rate decreases above the rotating shaft 18 of the impeller 15. However, the flow rate tends to increase below the rotating shaft 18.

  As shown in FIG. 2, the pump casing 112 is provided on the upstream side of the cylindrical main body 21 and the main body 21, and the pipe diameter is gradually reduced toward the discharge port 11 </ b> B of the suction casing 11. And a reduced diameter portion 122. In the second embodiment, the reduced diameter portion 122 is formed eccentrically with respect to the main body portion 21 in order to eliminate the above-described tendency.

  Specifically, the reduced diameter portion 122 is formed such that the bottom surface 21A of the main body 21 and the bottom surface 122A of the reduced diameter portion 122 connected to the discharge port 11B of the suction casing 11 are at the same height position. As shown in FIG. 3, the pipe center O1 on the upstream side of the reduced diameter portion 122 (on the discharge port 11B side of the suction casing 11) is located at the pipe center O2 of the main body portion 21 (at the axial center position of the rotary shaft 18). It is located vertically below the equivalent).

  According to the second embodiment, the pump casing 112 has an upper and lower space with respect to the rotary shaft 18 because the upstream side (inlet side) of the reduced diameter portion 122 is eccentric downward relative to the downstream side (outlet side). By changing the cross-sectional area ratio, it is possible to suppress the difference in the flow rate flowing up and down, and to realize equalization of the flow rate balance. For this reason, the water in which the upper and lower flow rate balance is adjusted flows into the impeller 15 so that the water pressurized uniformly by the impeller 15 can be injected.

  Further, according to the second embodiment, the reduced diameter portion 122 is formed such that the pipe bottom surface 21A of the main body portion 21 and the pipe bottom surface 122A of the reduced diameter portion 122 are formed at the same height position. Separation of the water flowing into the pump casing 112 can be prevented.

  Moreover, in 2nd Embodiment, as shown in FIG. 3, the pipe line center O1 and the main-body part 21 of the diameter-reduced part 122 upstream (discharge port 11B of the suction casing 11) with respect to the pipe-diameter D2 of the main-body part 21 are shown. The amount of eccentricity h with respect to the pipe center O2 is preferably 10% or less. The limit of the eccentricity h is set by the expansion angle θ (FIG. 1) and the pipe diameter expansion rate. In the eccentric direction, the pipe center O2 of the main body 21 is always set above the pipe center O1 of the discharge port 11B of the suction casing 11. If the amount of eccentricity h becomes excessively large, the pipe bottom surface 122A of the reduced diameter portion 122 is inclined upward toward the downstream side, which adversely affects the flow into the pump casing 112. According to this configuration, the flow rate balance of the water flowing through the pump casing 112 can be suitably adjusted, and the inflow into the pump casing 112 can be made uniform.

[Third Embodiment]
Next, the water jet propulsion device 210 according to the third embodiment will be described. FIG. 4 is a schematic cross-sectional view of the water jet propulsion device according to the third embodiment. FIG. 5 is a schematic cross-sectional view showing the configuration of the reduced diameter portion. FIG. 6 is a schematic cross-sectional view showing a state after the reduced diameter portion is eccentric. FIG. 7 is a schematic cross-sectional view showing the water jet propulsion device after the reduced diameter portion is eccentric. In addition, the same code | symbol is attached | subjected to the same component as 1st Embodiment, and detailed description is abbreviate | omitted. In the third embodiment, the basic configuration is the first embodiment, and the configuration of the pump casing 212 is different from that of the first embodiment.

  As described above, in the piping 14 configured to draw water from the water intake 2 </ b> A formed in the ship bottom 2, the flow rate balance of the water flowing through the piping channel 14 is lost, and the flow rate is reduced above the rotating shaft 18 of the impeller 15. The flow rate tends to increase below the rotary shaft 18. Further, the deviation in the flow rate balance varies greatly depending on the relationship between the ship speed and the pump flow rate.

  As shown in FIG. 4, the pump casing 212 is provided on the upstream side of the main body portion 21 and the main body portion 21, and the pipe diameter is gradually reduced toward the discharge port 11 </ b> B of the suction casing 11. And a reduced diameter portion 222. In the third embodiment, the reduced diameter portion 222 is configured to be able to adjust the amount of eccentricity with respect to the main body portion 21.

  The water jet propulsion unit 210 includes an elevating device (elevating unit) 30 that supports the pump casing 212 and the discharge casing 13 to be movable up and down on the ship bottom 2. The lifting device 30 is constituted by, for example, a hydraulic cylinder provided with a rod 31 that expands and contracts vertically, and the main body 21 of the pump casing 212 is fixed to the tip of the rod 31. Thereby, the main body 21 and the discharge casing 13 of the pump casing 212 are moved up and down by the expansion and contraction of the rod 31. Although not shown in FIGS. 4 and 7, between the outlet 13 </ b> B of the discharge casing 13 and the drain outlet 3 </ b> A of the stern 3, the structure prevents the intrusion of water following the elevation of the discharge casing 13. It has become.

  In the present embodiment, the impeller 15 also moves up and down together with the pump casing 212. Therefore, the first rotating shaft 118A connected to the cone portion 16 of the impeller 15 and the second rotating shaft 118B connected to the engine 19 are crank-connected by the joint shaft 118C and the pair of connecting pins 119. ing. Thereby, even if the pump casing 212 is raised and lowered, the rotation of the engine 19 can be suitably transmitted to the impeller 15.

  The diameter-reduced portion 222 of the pump casing 212 is configured to be eccentric following the elevation of the main body 21. Specifically, as shown in FIG. 5, the discharge port 11B ( A plurality of annular members 40A, 40B, 40C, and 40D that are arranged so that the pipe diameter is reduced in a stepwise manner, and a seal member 41 that seals water tightly between adjacent annular members. Configured. The seal member 41 is formed of a flexible resin material or the like, and can be deformed following the displacement of the annular member 40A. For this reason, as shown in FIG. 6, the diameter-reduced portion 222 follows the ascent of the main body portion 21, and the center positions of the annular members 40 </ b> A, 40 </ b> B, 40 </ b> C, 40 </ b> D are displaced. The amount of eccentricity on the (inlet side) can be easily adjusted. 5 and 6, the number of the annular members 40A, 40B, 40C, and 40D is four, but the present invention is not limited to this.

  According to the third embodiment, the diameter-reduced portion 222 of the pump casing 212 is configured to be eccentric following the elevation of the main body portion 21. For example, as shown in FIG. When the reduced diameter portion 222 is arranged concentrically with the main body portion 21 and the boat speed and the flow rate of water (engine speed) increase, as shown in FIG. The upstream side of 222 can be eccentric. According to this configuration, by dynamically adjusting the amount of eccentricity of the reduced diameter portion 222, a difference in flow rate flowing up and down in the pump casing 212 can be suppressed, and rectification in the pipeline 14 can be realized.

  As mentioned above, although embodiment of this invention was described, it is not restricted to an above-described form.

2 Ship bottom 2A Intake port 3 Stern 3A Drain port 10, 110, 210 Water jet propulsion machine 11 Suction casing 11A Suction port 11B Discharge port (exit part)
12, 112, 212 Pump casing 13 Discharge casing 14 Pipe line 15 Impeller (impeller)
17 Guide vane 17A Front edge 18 Rotating shaft 19 Engine 21 Body 21A Pipe bottom 22, 122, 222 Reduced diameter part 30 Lifting device (lifting unit)
40A, 40B, 40C, 40D Annular member 41 Seal member 122A Pipe bottom

Claims (2)

A suction casing attached to a water intake on the bottom of the ship, a pump casing connected to an outlet portion of the suction casing, and an axial flow type impeller disposed in the pump casing and rotating around a rotation axis, A water jet propulsion device that propels a ship by injecting water pressurized by an impeller to the rear of the stern,
The pump casing includes a cylindrical main body having a pipe diameter larger than the outlet portion of the suction casing, and an upstream side of the front edge of the impeller, and the outlet of the suction casing from the pipe diameter of the main body portion. A diameter-reduced portion that gradually decreases to the pipe diameter of the portion ;
An elevating part that elevates and lowers the main body part of the pump casing,
The reduced diameter portion is eccentric following the elevation of the main body, and is a water jet propulsion device. The reduced diameter portion includes a plurality of annular members arranged so that the pipe diameter is gradually reduced from the main body portion toward the outlet portion, and a seal member that seals between adjacent annular members. The water jet propulsion device according to claim 1 .

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