Turbo-type pump

Abstract

To inexpensively realize a constitution for pouring water into a portion of a mechanical seal.SOLUTION: A turbo-type pump comprises; a rotating shaft; a bearing supporting the rotating shaft; an impeller attached to the rotating shaft; a casing arranged so as to surround the impeller; and a suction nozzle and a discharge nozzle which are arranged at the casing. The pump also comprises: a mechanical seal arranged in a portion of the casing through which the rotating shaft passes on a suction nozzle side and sealing a clearance between the rotating shaft and the casing; a mechanical seal attachment portion arranged at the casing and accommodating the mechanical seal; a cooling space formed on an external peripheral side of the mechanical seal in the mechanical seal attachment portion; a suction fluid intake portion for taking in a part of a flow of a suction fluid which is sucked in from the suction nozzle; and an introduction flow passage for introducing the fluid taken in from the suction fluid intake portion into the cooling space.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a turbo pump having a mechanical seal at a portion of a casing through which a rotating shaft passes. [Background technology]

[0002] An example of a conventional turbo pump (such as a centrifugal pump) equipped with a mechanical seal at the portion of the casing through which the rotating shaft passes is described in Japanese Utility Model Application Laid-Open Publication No. 58-2392 (Patent Document 1). Patent Document 1 describes a structure in which a fluid (such as water) from the high-pressure side (discharge side) of the pump is injected into the mechanical seal portion via a pipe in order to cool the sliding members in the mechanical seal and to clean the mechanical seal portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 58-2392 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to cool and clean the sliding members that make up the mechanical seal, a sufficient effect cannot be achieved unless there is a flow of fluid around the sliding members of the mechanical seal. For this reason, in the design of Patent Document 1, a flow is forcibly generated by injecting the high-pressure side fluid into the part of the mechanical seal provided in the shaft through-hole close to the pressure on the low-pressure side.

[0005] However, in order to guide the high-pressure fluid to the low-pressure mechanical seal, it was necessary to install piping, and it was also necessary to provide a cooling fluid inlet hole in the casing to introduce the fluid from the piping to the mechanical seal, which resulted in increased manufacturing man-hours and equipment costs.

[0006] An object of the present invention is to provide a turbo pump that can inexpensively implement a structure for injecting water into the mechanical seal portion. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention provides a turbo pump comprising a rotating shaft, a bearing supporting the rotating shaft, an impeller attached to the rotating shaft, a casing arranged to surround the impeller, and a suction nozzle and a discharge nozzle provided in the casing, characterized in that the pump is equipped with a mechanical seal provided at a portion of the casing where the rotating shaft penetrates the suction nozzle side and seals a gap between the rotating shaft and the casing, a mechanical seal mounting portion provided on the casing and accommodating the mechanical seal, a cooling space formed on the outer periphery of the mechanical seal in the mechanical seal mounting portion, a suction fluid intake portion that takes in a portion of the flow of suction fluid sucked in from the suction nozzle, and an introduction flow path that leads the fluid taken in from the suction fluid intake portion to the cooling space. Effect of the Invention

[0008] According to the present invention, it is possible to obtain a turbo pump that can inexpensively realize a configuration for injecting water into the mechanical seal portion. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a vertical sectional view showing a first embodiment of a turbo pump according to the present invention. [Diagram 2] FIG. 2 is an enlarged view of a main portion of the mechanical seal shown in FIG. [Diagram 3] 3 is an enlarged view of a main portion around the suction fluid intake portion of FIG. 2, seen from direction A. FIG. [Figure 4] FIG. 1 is a vertical cross-sectional view showing an example of a typical turbo pump. [Diagram 5] 5 is an enlarged view of a main part of the mechanical seal shown in FIG. 4. [Figure 6]FIG. 4 is a diagram showing a turbo pump according to a second embodiment of the present invention, and corresponds to FIG. 2. [Figure 7] 7 is an enlarged view of a main portion around the suction fluid intake portion of FIG. 6, as viewed from the direction A. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the turbo pump of the present invention will be described with reference to the drawings. In each drawing, the same reference numerals denote the same or corresponding parts. EXAMPLES

[0011] A turbo pump according to a first embodiment of the present invention will be described with reference to FIGS. Before describing the first embodiment of the present invention, a general example of a turbo pump equipped with a mechanical seal will be described with reference to Figures 4 and 5. Figure 4 is a vertical cross-sectional view showing an example of a single-shaft multi-stage centrifugal pump as a general turbo pump, and Figure 5 is an enlarged view of the main part of the mechanical seal in Figure 4.

[0012] As shown in Fig. 4, a single-shaft multi-stage centrifugal pump as a turbo pump is roughly composed of a rotating shaft (main shaft) 2 provided to penetrate a casing 1, a bearing 3 supporting the rotating shaft 2, a plurality of impellers (centrifugal impellers) 4 attached to the rotating shaft 2 in multiple stages, a suction nozzle 5 for directing suction fluid to the first impeller of the multi-stage impellers 4, and a discharge nozzle 6 for guiding the high-pressure discharge fluid discharged from the last impeller of the multi-stage impellers 4 and sending it to a use. The casing 1 is provided to surround the impellers 4 provided in multiple stages, and the suction nozzle 5 and discharge nozzle 6 are provided in the casing 1.

[0013] The rotating shaft 2 is rotated directly or via a coupling or the like by a driving source such as a motor or an engine (not shown), and a fluid such as water sucked in from a suction nozzle 5 is pressurized by a plurality of impellers 4 fixed to the rotating shaft 2, successively from the first stage impeller to the final stage impeller, and discharged from a discharge nozzle 6 and sent to the application via a discharge piping.

[0014] Further, a mechanical seal 7 is provided at a portion where the rotating shaft 2 penetrates the suction side (suction nozzle 5 side) of the casing 1 to seal a gap formed between the casing 1 and the rotating shaft 2. This mechanical seal 7 is configured to suppress leakage of fluid to the outside of the casing 1.

[0015] In order to cool the sliding members constituting the mechanical seal 7, the mechanical seal 7 is configured so that a portion of the high-pressure discharge fluid discharged from the final stage impeller 4 is introduced through a piping 8 provided outside the casing 1 and a cooling fluid introduction hole 9 formed in the casing 1.

[0016] The configuration of the mechanical seal 7 will be described in detail with reference to FIG. 5, which is an enlarged view of the main part of the mechanical seal 7 and its vicinity in FIG. 5, the mechanical seal 7 is composed of a fixed ring 7a fixed to the casing 1 and a rotating ring 7b fixed to the rotating shaft 2 and rotating with the rotating shaft, and the fixed ring 7a and the rotating ring 7b are brought into contact with each other and caused to slide at a sliding portion 10, thereby preventing leakage of fluid to the outside of the casing 1. For this reason, the sliding portion 10 of the mechanical seal 7 generates heat.

[0017] The mechanical seal 7 is installed in a mechanical seal mounting portion 11 provided in the shaft-penetrating portion of the casing 1, and this mechanical seal mounting portion 11 is provided with a cooling space 11a formed on the outer periphery of the mechanical seal 7.

[0018] In order to prevent overheating of the mechanical seal 7 due to heat generation at the sliding part 10 of the mechanical seal 7, a part of the discharge fluid is introduced into the cooling space 11a as shown by arrow a via piping 8 and cooling fluid introduction hole 9. The flow of the cooling fluid shown by arrow a cools the mechanical seal 7 as it flows through the cooling space 11a, and then flows out from a gap (shaft outer periphery gap) 12 between the outer periphery of the rotating shaft 2 and the casing 1, merges with the suction flow b from the suction nozzle 5, and is sucked into the impeller 4.

[0019] The flow a of the cooling fluid flowing into the cooling space 11a not only cools the mechanical seal 7 but also washes away foreign matter remaining in the mechanical seal mounting portion 11, thereby cleaning it.

[0020] Furthermore, when the turbo pump is stopped, the fluid that had been accumulated in the casing 1 is released, and external air flows in, causing air to accumulate in the cooling space 11a. If air accumulates in the cooling space 11a when the turbo pump is started, the mechanical seal 7 may not be cooled sufficiently. For this reason, air bleeding is required to bleed the air out of the cooling space 11a when the turbo pump is started. To bleed the air, the casing 1 has an air bleed hole 13 at one location on the circumference (on the upper side) that connects the cooling space 11a with the suction flow passage 5a side (see FIG. 4).

[0021] By providing this air vent hole 13, when the water level in the casing 1 is raised at the start of the turbo pump, the air remaining in the cooling space 11a can be vented to the suction passage 5a side through the air vent hole 13. Therefore, it is possible to prevent the cooling effect of the mechanical seal 7 from decreasing due to air remaining in the cooling space 11a.

[0022] In the example shown in FIG. 4, the fluid pressurized by the operation of the centrifugal pump itself is taken out through piping 8, but there is also a case where the cooling fluid is supplied to the cooling fluid inlet hole 9 from an external high-pressure water source.

[0023] In a typical turbo pump as shown in Fig. 4 and Fig. 5 described above, in order to cool and clean the sliding members such as the stationary ring 7a and the rotating ring 7b constituting the mechanical seal 7, a part of the discharge fluid discharged from the impeller 4 in the final stage is introduced into the mechanical seal 7 through a piping 8 and a cooling fluid introduction hole 9 formed in the casing 1. For this reason, in a turbo pump as shown in Fig. 4 and Fig. 5, in order to guide the high-pressure side fluid to the low-pressure side mechanical seal portion, it is necessary to provide a piping 8 provided outside the casing 1, and a cooling fluid introduction hole 9 formed in the casing 1 to introduce the fluid from the piping 8 to the mechanical seal mounting portion 11, which poses a problem of increased manufacturing man-hours and high equipment costs.

[0024] A turbo pump according to a first embodiment of the present invention for solving this problem will be described below with reference to Figures 1 to 3. Figure 1 is a longitudinal sectional view of the turbo pump according to the first embodiment of the present invention, Figure 2 is an enlarged view of the mechanical seal in Figure 1, and Figure 3 is an enlarged view of the periphery of the suction fluid intake in Figure 2, as viewed from the direction A. In the turbo pump according to this first embodiment shown in Figures 1 to 3, the parts given the same reference numerals as those in Figures 4 and 5 above are the same or corresponding parts, and in the description of this first embodiment, the same parts as those in Figures 4 and 5 will be omitted, and the different parts will be mainly described.

[0025] As shown in Fig. 1, the turbo pump (single-shaft multi-stage centrifugal pump) of the present embodiment 1 has the same basic configuration as the turbo pump described with reference to Fig. 4, and includes a rotating shaft 2, a bearing 3 supporting the rotating shaft 2, an impeller 4 attached to the rotating shaft 2, a casing 1 provided to surround the impeller 4, and a suction nozzle 5 and a discharge nozzle 6 provided in the casing 1. As shown in Figs. 1 and 2, a mechanical seal 7 for sealing a gap between the rotating shaft 2 and the casing 1 is provided at a portion where the rotating shaft 2 penetrates the suction side (suction nozzle 5 side) of the casing 1, and this mechanical seal 7 is accommodated in a mechanical seal mounting portion 11 provided in the casing 1. In addition, a cooling space 11a is formed on the outer circumferential side of the mechanical seal 7 in the mechanical seal mounting portion 11.

[0026] The above configuration is the same as that of the turbo pump shown in Figures 4 and 5, but the turbo pump of this embodiment does not have the piping 8 shown in Figure 4 or the cooling fluid introduction hole 9 formed in the casing 1. Instead, as shown in Figures 1 and 2, this embodiment is provided with a suction fluid intake section 14 for taking in a part of the flow of suction fluid (suction flow) b sucked into the impeller 4 from the suction nozzle 5 into the cooling space 11a, and an introduction flow path 15 for guiding the fluid taken in from the suction fluid intake section 14 to the cooling space 11a. In this embodiment, an example is shown in which the introduction flow path 15 is also used as the air vent hole 13, but the introduction flow path 15 may be provided in the casing 1 separately from the air vent hole 13, or a part of the suction flow b taken in by the suction fluid intake section 14 may be taken in the cooling space 11a via an introduction flow path formed of a piping.

[0027] In this embodiment, the suction fluid intake section 14 is disposed downstream close to the introduction flow passage 15 (air vent hole 13) on a wall surface (suction flow passage wall surface) 5b of the suction flow passage 5a formed in the casing 1. The suction fluid intake section 14 is composed of a protrusion (protrusion) 14a protruding from the suction flow passage wall surface 5b toward the suction flow passage 5a.

[0028] The configuration of the suction fluid intake section 14 will be described in detail with reference to Fig. 3. Fig. 3 is a view of the periphery of the suction fluid intake section 14 as viewed from the direction A in Fig. 2, and the suction fluid intake section 14 formed with the protrusions 14a is formed in a crescent shape as viewed from the direction A (the suction flow path 5a side). That is, the suction fluid intake section 14 is formed in a concave shape in the direction toward the suction flow b (the direction facing the upstream side of the suction flow b), and is configured to efficiently take in a part of the suction flow b into the introduction flow path 15 (air vent hole 13).

[0029] The suction fluid intake portion 14 may be formed as a crescent-shaped protrusion by machining on the suction flow path wall surface 5b of the casing 1. Alternatively, the suction fluid intake portion 14 may be provided by joining a crescent-shaped part to the suction flow path wall surface 5b by welding.

[0030] In this embodiment, the air vent hole 13 is used as the introduction flow passage 15 for guiding the fluid taken in from the suction fluid intake portion 14 to the cooling space 11a, but the air vent hole 13 is generally provided at one location on the upper side of the circumference of the casing 1 so as to communicate only with the suction flow passage 5a and the upper side of the cooling space 11a. For this reason, in order to further enhance the cooling effect of the mechanical seal 7, it is preferable to provide an introduction flow passage 15 that communicates with the suction flow passage 5a and the lower side and the middle side of the cooling space 11a. In this case, it is preferable to provide the air vent hole 13 and another introduction flow passage 15 different from the air vent hole 13, and configure the air vent hole 13 and the introduction flow passage 15 as an introduction flow passage that introduces a part of the suction flow into the cooling space 11a.

[0031] In the above description of this embodiment, an example has been shown in which the suction fluid intake portion 14 is configured with a crescent-shaped protrusion 14a, but the shape of the suction fluid intake portion 14 is not limited to a crescent shape and may be a semicircular shape, a V-shape, a U-shape, or the like. Any shape may be used as long as the concave protrusion 14a facing the upstream side of the suction flow b to the impeller 4 can guide a portion of the suction flow b to the cooling space 11a of the mechanical seal mounting portion 11 via an introduction passage (air vent hole 13 and introduction passage 15).

[0032] In the first embodiment, with the above-described configuration, a part of the suction flow b such as water sucked from the suction nozzle 5 collides with the suction fluid intake 14 such as the crescent-shaped protrusion 14a formed on the suction flow passage wall surface 5b, and flows into the cooling space 11a of the mechanical seal mounting portion 11 from the air vent hole 13 (introduction flow passage 15) provided on the upstream side of the suction fluid intake 14 as shown by the arrow c. The fluid that has flowed into the cooling space 11a flows as shown by the arrow c, and cools the mechanical seal 7 when passing near the sliding portion 10 of the mechanical seal 7. The fluid that has flowed into the cooling space 11a also washes away foreign matter remaining in the mechanical seal mounting portion 11, thereby cleaning it.

[0033] Then, as shown by the arrow c, the fluid in the cooling space 11a passes through the shaft outer periphery gap 12 between the casing 1 and the rotating shaft 2, flows out into the suction flow passage 5a, merges with the suction flow b, and is sucked into the impeller 4. The fluid sucked into the impeller 4 is successively pressurized by the impellers 4 provided in multiple stages, and is discharged from the discharge nozzle 6 and sent to the intended use via the discharge piping. When the turbo pump is started, air is bled from the cooling space 11a through the air bleed hole 13, in the same manner as in the turbo pump described with reference to FIGS.

[0034] In this embodiment, the air vent hole 13 also serves as an introduction passage 15 for introducing a portion of the suction flow b into the cooling space 11a. Therefore, during normal operation of the turbo pump, a portion of the suction flow b sucked in from the suction nozzle 5 collides with the suction fluid intake portion 14 and flows into the cooling space 11a of the mechanical seal mounting portion 11 from the air vent hole 13 (introduction passage 15) located upstream of the suction fluid intake portion 14 as shown by the arrow c. Therefore, a flow of the cooling fluid is generated in the cooling space 11a, so that the mechanical seal can be effectively cooled and cleaned.

[0035] As described above, the air vent hole 13 is provided at one location on the circumference of the casing 1 so as to communicate only with the suction passage 5a and the upper side of the cooling space 11a. There are cases where only this one air vent hole 13 is not able to introduce a sufficient amount of fluid into the cooling space 11a. In this case, it is advisable to provide the casing 1 with one or more introduction passages 15 and suction fluid intakes 14 that communicate with the suction passage 5a and the lower and middle sides of the cooling space 11a in addition to the air vent hole 13, and to introduce a part of the suction flow into the cooling space 11a through the air vent hole 13 and the introduction passage 15. This can further improve the cooling effect and cleaning effect of the mechanical seal 7.

[0036] In this embodiment, during normal operation, the air vent hole 13 also serves as the introduction flow path 15 that guides a portion of the suction flow b to the cooling space 11 a. However, the air vent hole 13 may not also serve as the introduction flow path 15, and the introduction flow path 15 may be provided separately from the air vent hole 13.

[0037] According to this embodiment, a part of the suction flow b sucked into the impeller 4 is guided to the cooling space 11a of the mechanical seal mounting portion 11, which makes it possible to eliminate the need for the piping 8 and the cooling fluid introduction hole 9 for sending a part of the discharge fluid to the cooling space 11a of the mechanical seal mounting portion 11 in order to cool and clean the mechanical seal 7. Therefore, it is possible to obtain a turbo pump that can inexpensively realize a configuration for injecting water into the mechanical seal 7. EXAMPLES

[0038] Next, a turbo pump according to a second embodiment of the present invention will be described with reference to Figures 6 and 7. Figure 6 is a view showing a turbo pump according to a second embodiment of the present invention, and corresponds to Figure 2, and Figure 7 is an enlarged view of the periphery of the suction fluid intake section in Figure 6, viewed from the direction A. In the turbo pump of this second embodiment, parts denoted with the same reference numerals as in Figures 1 to 5 described above are the same or corresponding parts, and in the description of this second embodiment, the same parts as in Figures 1 to 5 will be omitted, and different parts will be mainly described below.

[0039] The turbo pump (single-shaft multi-stage centrifugal pump) of the second embodiment has the same basic configuration as the turbo pump of the first embodiment described with reference to Figs. 1 and 2. The differences from the first embodiment will be described below. In the first embodiment described above, an example was described in which the suction fluid intake portion 14 is configured with a protrusion 14a in order to take in a part of the flow (suction flow) b of the suction fluid sucked in from the suction nozzle 5 (see Fig. 1) into the cooling space 11a of the mechanical seal mounting portion 11. That is, an example was described in which the protrusion 14a is provided on the suction flow passage wall surface 5b on the downstream side close to the air vent hole 13 or the introduction flow passage 15 to form the suction fluid intake portion 14.

[0040] 6 and 7, in the second embodiment, instead of the protrusion 14a, a recessed portion 14b is provided upstream from the position of the air vent hole 13 or the introduction flow path 15 to serve as the suction fluid intake portion 14. The recessed portion 14b is shaped to become gradually deeper toward the air vent hole 13 or the introduction flow path 15, and is configured to guide a part of the suction flow b of the suction flow path 5a (see FIG. 1) into the cooling space 11a of the mechanical seal mounting portion 11 via the air vent hole 13 or the introduction flow path 15. The recessed portion 14b can be formed by, for example, machining the suction flow passage wall surface 5b of the casing 1. The other configurations are the same as those of the first embodiment described above.

[0041] The configuration of this embodiment 2 can provide the same effects as those of the above-mentioned embodiment 1. Furthermore, according to this embodiment 2, as shown in Fig. 6, a part of the suction flow b can be smoothly guided to the air vent hole 13 or the introduction flow path 15, which has the effect of increasing the amount of fluid that can be taken in from each introduction flow path (or air vent hole).

[0042] The present invention is not limited to the above-described embodiment, but includes various modified examples. For example, in the above-described embodiment, the present invention is applied to a single-shaft multi-stage centrifugal pump as a turbo pump, but the present invention is not limited to the single-shaft multi-stage centrifugal pump, and can be similarly applied to a single-stage centrifugal pump or a mixed-flow pump. Also, although an example has been described in which the suction fluid intake portion 14 is configured with the protrusions 14a and the recessed portions 14b, the present invention is not limited to these and may be configured such that a portion of the suction flow path 5a (for example, a portion of the suction flow path wall surface 5b) is provided with a portion whose shape changes suddenly to forcibly introduce part of the suction flow b into the mechanical seal attachment portion 11. Also, the suction fluid intake portion is not limited to being provided on the suction flow path wall surface 5b and may be provided in the suction flow path 5a via piping or the like, and even when piping is provided, the suction flow is introduced into the portion of the mechanical seal provided on the suction side, which has the effect of shortening the piping. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Also, the above-mentioned embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all of the described configurations. [Explanation of symbols]

[0043] 1: casing, 2: rotating shaft, 3: bearing, 4: impeller, 5: suction nozzle, 5a: suction flow passage, 5b: wall surface of the suction flow passage (wall surface of the suction flow passage), 6: Discharge nozzle, 7: mechanical seal, 7a: stationary ring, 7b: rotating ring, 8: piping, 9: cooling fluid inlet hole, 10: sliding part, 11: mechanical seal mounting portion, 11a: cooling space, 12: shaft outer periphery gap, 13: air vent hole (inlet flow path), 14: suction fluid intake portion (14a: protrusion portion, 14b: recessed portion), 15: inlet channel, a, c: Cooling fluid flow, b: Suction fluid flow (suction flow).

Claims

1. A turbo pump comprising: a rotating shaft; a bearing supporting the rotating shaft; an impeller attached to the rotating shaft; a casing provided to surround the impeller; and a suction nozzle and a discharge nozzle provided in the casing, a mechanical seal provided at a portion of the casing on the suction nozzle side where the rotary shaft passes through, for sealing a gap between the rotary shaft and the casing; a mechanical seal mounting portion provided in the casing and accommodating the mechanical seal; a cooling space formed on an outer circumferential side of the mechanical seal in the mechanical seal mounting portion; a suction fluid intake section that takes in a portion of the flow of the suction fluid sucked through the suction nozzle; an introduction flow passage that introduces the fluid taken in through the suction fluid intake portion into the cooling space; A turbo pump comprising:

2. 2. The turbo pump according to claim 1, 2. A turbo pump according to claim 1, wherein the suction fluid intake portion is provided on a wall surface of the suction flow passage in the casing.

3. 3. The turbo pump according to claim 2, A turbo pump characterized in that the suction fluid intake portion is composed of a protrusion provided on a wall surface of the suction flow passage in the casing, the protrusion being located downstream adjacent to the introduction flow passage.

4. 4. The turbo pump according to claim 3, A turbo pump characterized in that the protrusion is formed so as to protrude from a wall surface of the suction flow passage toward the suction flow passage, and the protrusion is formed in a concave shape in a direction facing the upstream side of the flow of the suction fluid.

5. 5. The turbo pump according to claim 4, A turbo pump, characterized in that the protrusion is formed in a crescent shape facing upstream of the flow of the suction fluid.

6. 6. The turbo pump according to claim 5, 2. A turbo pump according to claim 1, wherein the protrusion is formed on a wall surface of the suction passage by machining, or by welding a crescent-shaped part to the wall surface of the suction passage.

7. 5. The turbo pump according to claim 4, 2. A turbo pump, comprising: a first protrusion portion having a first shape and a second shape, the first shape being a semicircular shape, a V shape, or a U shape, the second shape being directed toward the upstream side of the flow of the suction fluid.

8. 2. The turbo pump according to claim 1, a suction flow passage through which the suction fluid flowing in from the suction nozzle flows and an upper part of the cooling space is provided, the suction fluid intake section is disposed downstream adjacent to the air vent hole, and the air vent hole is utilized as the introduction flow passage.

9. 9. The turbo pump according to claim 8, a suction passage through which the suction fluid flowing in from the suction nozzle flows and the cooling space are communicated with each other, and an introduction passage different from the air vent hole is provided; the suction fluid intake portion is provided for each of the air vent hole and another of the introduction flow paths different from the air vent hole, 2. A turbo pump according to claim 1, wherein the introduction passage is constituted by the air vent hole and another introduction passage different from the air vent hole.

10. 3. The turbo pump according to claim 2, The intake fluid intake portion is formed by a recessed portion provided on a wall surface of the intake passage in the casing, The turbo pump, wherein the recessed portion is provided upstream from the inlet flow passage and is configured to have a shape that gradually becomes deeper toward the inlet flow passage.

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