Pump and pump device

Abstract

To provide a pump that allows liquid necessary for self-priming operation to remain in a pump casing without requiring a check valve.SOLUTION: A pump comprises a suction side liquid tank part having a gas-liquid separation chamber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pump and a pumping device. [Background technology]

[0002] While a typical centrifugal pump needs to be multi-staged to achieve a low flow rate and a high head, there are also known pumps (e.g., cascade pumps) that have a compact structure that achieves a low flow rate and a high head without being multi-staged.

[0003] Miniaturized pumps are expected to be used in a variety of fields, including pharmaceuticals and chemical synthesis. In particular, in recent years, there has been active development of chemical synthesis flows specialized for small-lot, multi-product production, and it is desirable to incorporate such pumps into chemical synthesis flows. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 50-138406 [Patent Document 2] Japanese Patent Publication No. 51-25811 [Patent Document 3] Japanese Patent Publication No. 59-103987 [Patent Document 4] Jikko No. 45-32185 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, a check valve is installed in the suction pipe connected to the pump to prevent water from falling into the suction pipe when the pump stops operating. The check valve keeps the pumped liquid remaining in the pump casing. Therefore, the pump can resume self-priming operation without supplying priming water to the pump casing.

[0006] However, when transferring special liquids such as chemicals, it is necessary to improve the cleanability of the pump. The purpose of improving cleanability is to prevent chemical A from mixing with chemical B when transferring another chemical (e.g., chemical A) after transferring another chemical (e.g., chemical B).

[0007] Because cleaning fluid is expensive, it is necessary to minimize the amount of pumped fluid remaining in the pump casing and reduce the amount of cleaning fluid used in order to reduce costs. One way to reduce the amount of pumped fluid remaining in the pump casing is to omit the check valve. On the other hand, if more pumped fluid than necessary is discharged from the pump, priming water must be supplied again to the pump when it is restarted.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a pump and a pump device that allows the liquid necessary for self-priming operation to remain in the pump casing without requiring a check valve. [Means for solving the problem]

[0009] In one aspect, a pump is provided that includes a rotating shaft, an impeller attached to the rotating shaft, a pump casing that houses the impeller and forms an annular flow path between the impeller and the pump casing, and a suction-side liquid tank portion that communicates with a suction flow path connected to the annular flow path and has a gas-liquid separation chamber.

[0010] In one aspect, the pump is provided with a discharge-side liquid tank portion that communicates with a discharge flow path connected to the annular flow path and has a gas-liquid separation chamber, and the suction-side liquid tank portion has a gas-liquid separation chamber that is larger than that of the discharge-side liquid tank portion. In one embodiment, the suction-side liquid tank portion and the discharge-side liquid tank portion are integrally formed. In one aspect, the suction-side liquid tank portion and the discharge-side liquid tank portion are formed in the pump casing.

[0011] In one embodiment, the pump includes a tank cover that closes the suction-side liquid tank portion. In one embodiment, the suction passage has a cross-sectional area equal to or larger than that of the discharge passage connected to the annular passage. In one aspect, the suction-side liquid tank section is disposed downstream of the suction flow path in the direction of flow of liquid flowing backward through the pump.

[0012] In one aspect, a pump device is provided, the pump device comprising the pump described above and a motor that drives the pump.

[0013] In one aspect, the pump device comprises a drive shaft connected to a rotating element of the motor and a magnetic coupling that transmits the rotational force of the drive shaft to the rotating shaft, and the magnetic coupling comprises a motor-side magnet fixed to the drive shaft and a pump-side magnet fixed to the rotating shaft, and the motor-side magnet and the pump-side magnet are arranged in a straight line along a central axis extending parallel to the rotating shaft and the drive shaft. In one aspect, the pump device comprises a coupling case that houses the pump side magnet, a coupling cover that closes the open end of the coupling case, and a detachment prevention pin that prevents the coupling cover from detaching from the coupling case, the detachment prevention pin being inserted into a fastening hole formed in the rotating shaft. In one aspect, the pump device comprises a disk holder fixed to the rotating shaft, a communicating hole formed in the impeller, and a locking pin connected to the disk holder, and the locking pin is inserted into the communicating hole to fix the disk holder to the impeller.

[0014] In one embodiment, the pump device includes a thrust disk accommodated in the accommodation recess of the disk holder, and the thrust disk has a rotation prevention portion formed on its outer circumferential surface. In one aspect, the pump casing includes a casing cover arranged opposite the impeller, and the casing cover has a flow groove that communicates with the communication hole and extends toward the low-pressure side flow path of the annular flow path. In one aspect, the pump device includes a bearing that rotatably supports the rotating shaft, and the bearing has a groove that allows liquid that has flowed into the gap between the rotating shaft and the bearing to pass through. In one aspect, the bearing has a main body portion extending parallel to the rotation axis and a flange portion connected to the main body portion, and the groove has an axial groove formed in the main body portion and a radial groove formed in the flange portion. [Effects of the Invention]

[0015] The pump is provided with a suction-side liquid tank having a gas-liquid separation chamber, so that the pump can retain the liquid necessary for self-priming operation inside the pump casing. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 illustrates an embodiment of a pump. [Figure 2] 2 is a diagram showing a pump device including the pump shown in FIG. 1. FIG. [Figure 3] FIG. 2 is a perspective view showing the pump shown in FIG. [Figure 4] FIG. 1 is a diagram showing the flow of liquid during self-priming operation (and normal operation) of the pump. [Figure 5] FIG. 10 is a diagram showing the flow of liquid immediately after the pump operation is stopped. [Figure 6] FIG. 10 is a diagram showing the flow of liquid flowing backward after the pump is stopped. [Figure 7] FIG. 10 is a diagram showing a rotation axis that moves along the central axis direction. [Figure 8] FIG. 10 is a diagram showing a comparative example of a rotation axis inclined relative to the central axis. [Figure 9] 10A and 10B are views showing a coupling case and a coupling cover fixed to a rotating shaft. [Figure 10] FIG. 10 is a diagram showing a disk holder that transmits the rotational force transmitted to the rotating shaft to the impeller. [Figure 11] FIG. 10 is a diagram showing a disk holder that transmits the rotational force transmitted to the rotating shaft to the impeller. [Figure 12] FIG. 10 is a view showing a thrust disk accommodated in an accommodating recess of a disk holder. [Figure 13] FIG. 10 is a view showing a thrust disk accommodated in an accommodating recess of a disk holder. [Figure 14] FIG. 14(a) is a perspective view showing a bearing arranged on the motor side, and FIG. 14(b) is a cross-sectional view taken along line aa in FIG. 14(a). [Figure 15] FIG. 10 is a diagram showing a number of communication holes greater than the number of anti-rotation pins. [Figure 16] 10A and 10B are diagrams showing flow grooves formed in a casing cover. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings described below, identical or corresponding components are designated by the same reference numerals, and duplicated descriptions will be omitted. In the multiple embodiments described below, the configuration of an embodiment that is not particularly described is the same as that of other embodiments, and therefore duplicated descriptions will be omitted.

[0018] Fig. 1 is a diagram showing one embodiment of a pump. Fig. 2 is a diagram showing a pump device including the pump shown in Fig. 1. Fig. 3 is a perspective view showing the pump shown in Fig. 1. The pump device PA includes a pump P and a motor M that drives the pump P.

[0019] In this embodiment, the pump P is a self-priming cascade pump that can achieve a small flow rate and a high head. The pump P includes a rotating shaft 2, an impeller 1 attached to the rotating shaft 2, and a pump casing PC that houses the impeller 1 and forms an annular flow passage 13 between the impeller 1 and the pump casing PC.

[0020] The impeller 1 has a disk shape and has a plurality of radial grooves 1a formed on the periphery of the impeller 1. The annular flow passage 13 is arranged to surround these plurality of radial grooves 1a. The pump P as a cascade pump is configured to generate a pressure difference in the annular flow passage 13 that surrounds the impeller 1 by rotating the impeller 1 having the plurality of radial grooves 1a formed therein.

[0021] The pump casing PC includes a casing main body 3, an inner casing 4 disposed inside the casing main body 3, and a casing cover 30 that closes the open end of the casing main body 3. In this embodiment, the casing main body 3 and the inner casing 4 are formed as separate members, but they may also be formed as an integrally molded member. Note that the inner casing 4 is not shown in FIG. 1.

[0022] The pump casing PC has a suction passage 12 connected to the annular passage 13, a discharge passage 14 connected to the annular passage 13 and arranged adjacent to the suction passage 12, and a return passage 20 arranged adjacent to the discharge passage 14. The suction passage 12, the discharge passage 14, and the return passage 20 are connected to the upper part of the annular passage 13 and extend upward from the annular passage 13.

[0023] The pump P is equipped with an intake-side liquid tank section 5A that is connected to the intake flow path 12 and has a gas-liquid separation chamber CH1, and an exhaust-side liquid tank section 5B that is connected to the discharge flow path 14 and the return flow path 20 and has a gas-liquid separation chamber CH2.

[0024] The suction-side liquid tank 5A and the discharge-side liquid tank 5B are integrally configured. More specifically, the suction-side liquid tank 5A and the discharge-side liquid tank 5B are recesses formed in the upper surface of the pump casing PC (more specifically, the casing main body 3) and are arranged adjacent to each other.

[0025] If the suction-side liquid tank 5A and the discharge-side liquid tank 5B were constructed as separate members from the pump casing PC, it would be necessary to place seal members between the suction-side liquid tank 5A and the discharge-side liquid tank 5B and the pump casing PC to prevent liquid leakage. By constructing the suction-side liquid tank 5A and the discharge-side liquid tank 5B as an integrated unit, it is possible to omit seal members while reliably preventing liquid leakage.

[0026] The suction flow path 12 is connected to the lower part of the suction-side liquid tank section 5A. The discharge flow path 14 is connected to the upper part of the discharge-side liquid tank section 5B. The return flow path 20 is connected to the lower part of the discharge-side liquid tank section 5B.

[0027] The suction-side liquid tank section 5A is located upstream of the suction flow path 12 in the flow direction of the liquid sucked into the pump P. The discharge-side liquid tank section 5B is located downstream of the discharge flow path 14. Here, the "flow direction of the liquid sucked into the pump P" refers to the flow direction of the liquid during normal operation of the pump P.

[0028] In other words, when the liquid flows backward after the pump P is stopped, the suction-side liquid tank 5A is located downstream of the suction flow path 12 in the flow direction of the backward flowing liquid. The discharge-side liquid tank 5B is located upstream of the discharge flow path 14.

[0029] The pump P includes a tank cover 100 connected to a pump casing PC (more specifically, the casing main body 3). The tank cover 100 is a flat plate-shaped lid member. With the tank cover 100 placed on the casing main body 3, the tank cover 100 closes the suction-side liquid tank portion 5A and the discharge-side liquid tank portion 5B by tightening a plurality of bolts B. The tank cover 100 has a simple structure, which allows for simplification of the overall components of the pump P.

[0030] The pump P has a suction port 10 formed in the tank cover 100 and communicating with the gas-liquid separation chamber CH1, and a discharge port 15 formed in the tank cover 100 and communicating with the gas-liquid separation chamber CH2. The suction port 10 is connected to the suction pipe SP, and the discharge port 15 is connected to the discharge pipe DP.

[0031] The suction port 10 is located above the suction-side liquid tank 5A (in other words, the gas-liquid separation chamber CH1) when the tank cover 100 is connected to the pump casing PC. Similarly, the discharge port 15 is located above the discharge-side liquid tank 5B (in other words, the gas-liquid separation chamber CH2) when the tank cover 100 is connected to the pump casing PC.

[0032] The gas-liquid separation chamber CH1 has a liquid chamber LCHa formed on the pump casing PC side and a gas chamber GCHa formed on the tank cover 100 side. The suction port 10, located at the top of the suction-side liquid tank section 5A, is connected to the gas chamber GCHa.

[0033] The gas-liquid separation chamber CH2 has a liquid chamber LCHb formed on the pump casing PC side and a gas chamber GCHb formed on the tank cover 100 side. The discharge port 15, located at the top of the discharge-side liquid tank portion 5B, is in communication with the gas chamber GCHb.

[0034] The pump P is equipped with seal members (e.g., O-rings) Sa and Sb arranged between the pump casing PC and the tank cover 100. The seal member Sa is arranged to surround the discharge-side liquid tank 5B and prevents leakage of the liquid present in the discharge-side liquid tank 5B. Similarly, the seal member Sb is arranged to surround the suction-side liquid tank 5A and prevents leakage of the liquid present in the suction-side liquid tank 5A.

[0035] Figure 4 shows the flow of liquid during self-priming (and normal) operation of the pump. In order to quickly resume operation of the pump P, it is necessary to quickly discharge the gas that has entered the suction pipe SP after the water has fallen into the suction pipe SP.

[0036] During self-priming operation of the pump P, the liquid flowing through the suction pipe SP, together with the gas, flows into the annular flow path 13 through the suction port 10 and the suction flow path 12. When the impeller 1 rotates, the liquid that has flowed into the annular flow path 13 flows through the annular flow path 13 and is gradually pressurized. The pressurized liquid then flows out of the annular flow path 13 into the discharge flow path 14.

[0037] The liquid that has passed through the discharge flow path 14 and flowed into the discharge-side liquid tank section 5B is separated from the gas in the gas-liquid separation chamber CH2 and returned to the annular flow path 13 through the return flow path 20 (see the arrow in FIG. 4). The gas separated from the liquid is discharged to the outside through the discharge port 15.

[0038] In this embodiment, the gas-liquid separation chamber CH2 formed in the discharge-side liquid tank portion 5B has a volume necessary to separate the liquid and gas that have flowed in. Therefore, during self-priming operation of the pump P, the pump P can separate the gas from the liquid and quickly start normal operation. When the pump P starts normal operation, the liquid that has passed through the annular flow path 13 and been pressurized is transferred to the outside through the discharge flow path 14 and the discharge port 15.

[0039] Figure 5 shows the flow of liquid immediately after the pump is stopped. Figure 6 shows the flow of liquid that flows backward after the pump is stopped. When the transfer of the liquid is completed and the pump P is stopped, the liquid in the suction pipe SP drops, and air at atmospheric pressure flows into the pump P through the discharge port 15 (see Figure 5).

[0040] The air that flows into the pump P pushes the liquid present in the discharge-side liquid tank 5B toward the suction side of the pump P due to atmospheric pressure, causing the liquid to flow back (siphon effect). The gas that flows into the discharge-side liquid tank 5B passes through the gap between the impeller 1 and the pump casing PC and flows into the suction-side liquid tank 5A.

[0041] The gas-liquid separation chamber CH1 in the suction-side liquid tank 5A has a volume necessary to separate the liquid and gas that have flowed in. Therefore, the liquid remains in the suction-side liquid tank 5A (more specifically, the liquid chamber LCHa), while the gas that has separated from the liquid is discharged through the suction port 10. Once the gas is discharged, the backflow of the liquid eventually stops (the siphoning action stops). At this time, the liquid remains in the pump casing PC. Therefore, at least the annular flow path 13 is filled with liquid.

[0042] According to this embodiment, the pump P equipped with the suction-side liquid tank 5A can retain the liquid necessary for self-priming operation inside the pump P. Therefore, the pump P can start self-priming operation without supplying priming water. Furthermore, since the liquid can be retained inside the pump P, there is no need to install a check valve in the suction pipe SP.

[0043] By eliminating the check valve, the number of components for transporting the liquid can be reduced, and a simple flow path for transporting the liquid can be formed, which results in the liquid flow path being able to be cleaned with a minimum amount of cleaning liquid.

[0044] It is desirable that the gas-liquid separation chamber CH1 formed in the suction-side liquid tank 5A have a volume equal to or greater than that of the gas-liquid separation chamber CH2 formed in the discharge-side liquid tank 5B. More preferably, the gas-liquid separation chamber CH1 of the suction-side liquid tank 5A has a volume greater than that of the gas-liquid separation chamber CH2 of the discharge-side liquid tank 5B. With this configuration, gas can be more actively discharged when liquid backflows, and the siphoning action can be more effectively stopped.

[0045] Furthermore, in one embodiment, it is preferable that the cross-sectional area of ​​the suction passage 12 is equal to or greater than that of the discharge passage 14. With this configuration, the suction passage 12 as a whole is not covered with gas contained in the liquid flowing backward, so the siphoning action continues.

[0046] Generally, as the siphoning action continues, most of the liquid in the pump casing PC is discharged, making it necessary to supply priming water when restarting the pump P. In this embodiment, the pump P is equipped with a suction-side liquid tank portion 5A having a gas-liquid separation chamber CH1. Therefore, the siphoning action can be easily stopped. Furthermore, since the suction flow path 12 has a cross-sectional area equal to or greater than that of the discharge flow path 14, the liquid sucked into the pump P can be sufficiently transported. As a result, the pump performance of the pump P can be improved.

[0047] In this embodiment, the pump P includes both the suction-side liquid tank 5A and the discharge-side liquid tank 5B, but in one embodiment, the pump P may include at least the suction-side liquid tank 5A. Even with this configuration, the pump P can retain the liquid necessary for self-priming operation in the pump casing PC without requiring a check valve.

[0048] The following describes the differences between the pump P according to the above-described embodiment and the pump described in Patent Document 4. Patent Document 4 discloses a self-priming pump having complex curved surfaces and enclosed spaces. Patent Document 4 does not disclose a manufacturing method for such a pump, but pumps having such complex internal shapes are generally manufactured by casting.

[0049] In the chemical, medical, and pharmaceutical fields, the pump casing PC is cleaned with a cleaning liquid to prevent chemical liquid from remaining inside (especially the suction-side liquid tank 5A and discharge-side liquid tank 5B). From the viewpoint of improving cleanability, it is preferable that the liquid-contacting surface of the pump casing PC is a machined surface with a regular surface roughness rather than a cast surface. In particular, it is preferable that the suction-side liquid tank 5A (and discharge-side liquid tank 5B) have an inner surface that is a machined surface.

[0050] As described above, the pump in Patent Document 4 has a complex inner surface shape. Therefore, it is difficult to machine the inner surface of the pump, and when a pump with a cast metal surface is applied to the chemical / medical / pharmaceutical fields, it is difficult to improve the cleanability.

[0051] In this embodiment, the pump P has a divided structure including a pump casing PC and a tank cover 100 that closes the pump casing PC. Therefore, an operator can directly access the suction-side liquid tank 5A and the discharge-side liquid tank 5B, and easily machine the suction-side liquid tank 5A and the discharge-side liquid tank 5B into machined surfaces.

[0052] By removing all of the bolts B, the worker can remove the tank cover 100 from the casing body 3. By removing the tank cover 100, the worker can see the suction-side liquid tank section 5A and the discharge-side liquid tank section 5B formed on the top surface of the casing body 3. Therefore, the worker can visually check whether or not there is any liquid remaining inside the pump casing PC.

[0053] Furthermore, by removing the tank cover 100, the seal members Sa and Sb are exposed, so that an operator can easily replace the seal members with those that correspond to the quality of the handled liquid, as needed.

[0054] The structure of the pump device PA will be described below with reference to Fig. 2. The pump device PA includes a bracket 40 disposed between the pump casing PC and the motor M, and an inner housing BH disposed between the inner casing 4 and the bracket 40.

[0055] The bracket 40 and the inner housing BH have a cylindrical shape, and are arranged concentrically with the central axis CL of the rotary shaft 2. The inner housing BH is attached to the bracket 40.

[0056] The casing body 3, the inner casing 4, and the inner housing BH are sandwiched between the casing cover 30 and the bracket 40. In this state, the pump device PA is assembled by inserting the positioning pin PP into the casing cover 30, the inner casing 4, the inner housing BH, and the bracket 40.

[0057] The pump device PA includes bearings BR1 and BR2 that rotatably support the rotating shaft 2, a drive shaft MS that is connected to a rotating element RE of the motor M and is arranged in a straight line with the rotating shaft 2 along the direction of the central axis CL, and a magnetic coupling MC that transmits the rotational force of the drive shaft MS to the rotating shaft 2.

[0058] The rotating element RE is a combination of a rotor fixed to the drive shaft MS and a stator surrounding the rotor. Each of the bearings BR1 and BR2 is made of a non-metallic material such as resin. The bearings BR1 and BR2 are, for example, plain bearings. The bearing BR1 is mounted in an inner housing BH, which serves as a stationary member. The bearing BR2 is mounted in a casing cover 30, which also serves as a stationary member.

[0059] The magnetic coupling MC has a motor-side magnet MCa fixed to the drive shaft MS and a pump-side magnet MCb fixed to the rotating shaft 2. The motor-side magnet MCa and the pump-side magnet MCb are arranged in a straight line along the direction of the central axis CL.

[0060] The pump device PA includes a cover plate CP disposed between the motor-side magnet MCa and the pump-side magnet MCb. The cover plate CP is attached to the bracket 40 in a liquid-tight manner and is disposed between the bracket 40 and the inner housing BH. The cover plate CP is made of a non-magnetic material (e.g., resin) that is not affected by the magnetic force generated by the magnetic coupling MC.

[0061] The magnetic coupling MC is configured to generate a magnetic force between the motor-side magnet MCa and the pump-side magnet MCb. Therefore, when the motor-side magnet MCa rotates together with the drive shaft MS due to the driving of the rotating element RE, the magnetic force of the rotating motor-side magnet MCa acts on the pump-side magnet MCb. The magnetic force of the motor-side magnet MCa causes the pump-side magnet MCb to rotate the rotating shaft 2. In this way, the rotating shaft 2 rotates together with the pump-side magnet MCb.

[0062] The flow of liquid sucked into the pump device PA will be described below with reference to Fig. 2. When the impeller 1 rotates together with the rotation of the rotary shaft 2, the liquid flows into the annular flow path 13 through the suction port 10 and the suction flow path 12.

[0063] 2, the inner casing 4 has a through-flow passage 4a extending in the direction of the central axis CL. The through-flow passage 4a is connected to the annular flow passage 13. Therefore, most of the liquid flowing through the annular flow passage 13 flows through the discharge flow passage 14, while a portion of the liquid is introduced into the space on the motor M side through the through-flow passage 4a.

[0064] The inner housing BH has a communication passage BHa that communicates with the bearing BR1 (and the pump-side magnet MCb). The liquid that passes through the through passage 4a is introduced into the communication passage BHa and supplied to the internal space of the inner housing BH. The liquid supplied to the inner housing BH comes into contact with the bearing BR1 attached to the inner housing BH, cooling and lubricating the bearing BR1.

[0065] The motor-side magnet MCa is disposed in a sealed space surrounded by the motor M, the bracket 40, and the cover plate CP. Therefore, the liquid supplied to the internal space of the internal housing BH comes into contact with the cover plate CP, but does not come into contact with the motor-side magnet MCa.

[0066] This configuration eliminates the need for waterproofing the motor-side magnet MCa, while the pump-side magnet MCb is disposed in the internal space of the inner housing BH, making the pump-side magnet MCb waterproof.

[0067] Fig. 7 is a diagram showing the rotating shaft moving along the central axis. As shown in Fig. 7, in this embodiment, the magnetic coupling MC has a motor-side magnet MCa and a pump-side magnet MCb adjacent to each other along the central axis CL. Therefore, the rotating shaft 2 moves along the central axis CL toward the drive shaft MS due to the magnetic force generated between the motor-side magnet MCa and the pump-side magnet MCb.

[0068] Fig. 8 is a diagram showing a comparative example of a rotating shaft that is inclined relative to the central axis. As shown in Fig. 8, the rotating shaft is rotatably supported by bearings. In Fig. 8, the size of the gap between the rotating shaft and the bearings is exaggerated.

[0069] If a configuration different from the magnetic coupling MC according to this embodiment is used to apply a rotational force to the rotating shaft, the rotating shaft may tilt relative to the bearing. If the rotating shaft is rotated in this state, the rotation of the rotating shaft may cause it to slide against the bearing more than necessary, which may damage the bearing (and / or the rotating shaft).

[0070] According to this embodiment, the rotating shaft 2 and the drive shaft MS are connected by a magnetic coupling MC. Therefore, the rotating shaft 2 is rotatably supported by the bearing BR1 (and bearing BR2) without tilting. In other words, a constant gap can always be formed between the rotating shaft 2 and the bearing BR1 (and bearing BR2). This configuration can prevent damage to the bearings BR1 and BR2 (and / or the rotating shaft 2).

[0071] 9 is a diagram showing the coupling case and coupling cover fixed to the rotating shaft. The pump device PA includes a coupling case CCA that houses the pump-side magnet MCb, a coupling cover CCO that closes the open end of the coupling case CCA, and a detachment prevention pin P that prevents the coupling cover CCO from detaching from the coupling case CCA.

[0072] 9, the coupling case CCA has an outer cylinder portion CCA-1 and an inner cylinder portion CCA-2 that are connected to each other. The outer cylinder portion CCA-1 and the inner cylinder portion CCA-2 extend in the direction of the central axis CL and are arranged concentrically with the rotating shaft 2.

[0073] The inner cylinder portion CCA-2 is disposed radially inward of the outer cylinder portion CCA-1 and extends so as to protrude further toward the impeller 1 than the outer cylinder portion CCA-1. In other words, the length of the inner cylinder portion CCA-2 in the direction of the central axis CL is longer than the length of the outer cylinder portion CCA-1.

[0074] The inner cylindrical portion CCA-2 has an insertion hole CCA-2a extending perpendicular to the direction of the central axis CL. The insertion hole CCA-2a is formed on the tip side of the inner cylindrical portion CCA-2 and communicates with a fastening hole 2a formed in the rotating shaft 2. A separation prevention pin P is inserted into the insertion hole CCA-2a and the fastening hole 2a. The separation prevention pin P is a pin (e.g., a spring pin) configured so that its diameter can be elastically deformed.

[0075] When the coupling cover CCO is closed with the pump-side magnet MCb housed in the coupling case CCA, the insertion hole CCA-2a is exposed, allowing the operator to insert the anti-detachment pin P into the insertion hole CCA-2a and the fastening hole 2a while visually observing the insertion hole CCA-2a (and the fastening hole 2a).

[0076] The separation prevention pin P prevents the coupling cover CCO from separating from the coupling case CCA, and can fix the coupling case CCA (and the pump-side magnet MCb) to the rotating shaft 2.

[0077] 10 and 11 are diagrams showing a disk holder that transmits the rotational force transmitted to the rotating shaft to the impeller. The pump device PA includes a disk holder DH fixed to the rotating shaft 2, a communication hole 50 formed in the impeller 1, and a plurality of anti-rotation pins WP for fastening the disk holder DH to the impeller 1. In one embodiment, at least one anti-rotation pin WP may be provided.

[0078] The disc holder DH is fixed to the rotating shaft 2 by, for example, shrink fitting SF (see FIG. 7). The disc holder DH may also be fixed to the rotating shaft 2 by means of press fitting or the like.

[0079] The disc holder DH has a connecting hole DHa formed in the surface facing the impeller 1. The communicating hole 50 and the connecting hole DHa extend in the direction of the central axis CL. The anti-rotation pin WP is inserted into the connecting hole DHa and the communicating hole 50.

[0080] When the anti-rotation pin WP is inserted, it fixes the disc holder DH to the impeller 1. The disc holder DH is fixed to the rotating shaft 2. Therefore, when the rotating shaft 2 rotates, the rotational force of the rotating shaft 2 is transmitted to the impeller 1 through the disc holder DH.

[0081] According to this embodiment, the anti-rotation pin WP has a structure that connects the disc holder DH and the impeller 1. With this structure, the impeller 1 does not need to have a structure (for example, a protrusion) on either side for connecting to the disc holder DH, and the impeller 1 can have both flat sides.

[0082] Therefore, the size of the gap between the impeller 1 and the inner casing 4 and casing cover 30 arranged on both sides of the impeller 1 can be minimized (see FIG. 2). Since the pump performance depends on the size of this gap, minimizing this gap is important for improving the pump performance. In one embodiment, the impeller 1 may have machined surfaces formed on both sides. In this way, manufacturing the impeller 1 by surface grinding allows for easy dimensional control.

[0083] 12 and 13 are diagrams showing a thrust disk accommodated in the accommodation recess of the disk holder. The pump device PA includes a thrust disk TD accommodated in the accommodation recess RC of the disk holder DH.

[0084] The thrust disk TD is made of, for example, ceramics, etc. The thrust disk TD is held by the disk holder DH and is disposed opposite the bearing BR1 (see FIG. 2), and is configured to rotate together with the disk holder DH.

[0085] The thrust disk TD has a rotation prevention portion TDa that prevents the thrust disk TD from rotating relative to the disk holder DH. The rotation prevention portion TDa is formed on the outer peripheral surface of the thrust disk TD and has a flat shape. The installation recess RC of the disk holder DH has a flat portion DHb, just like the thrust disk TD.

[0086] The thrust disk TD is accommodated in the disk holder DH so that the anti-rotation portion TDa and the flat portion DHb face each other. As a result, the thrust disk TD does not rotate relative to the disk holder DH but rotates integrally with the disk holder DH.

[0087] Fig. 14(a) is a perspective view showing a bearing arranged on the motor side, and Fig. 14(b) is a cross-sectional view taken along line aa in Fig. 14(a). The bearing BR1 has a main body portion BR1a extending parallel to the rotating shaft 2, and a flange portion BR1b connected to the main body portion BR1a.

[0088] The bearing BR1 has grooves BG that allow the passage of liquid that has flowed into the gap between the rotating shaft 2 and the bearing BR1. More specifically, the grooves BG include axial grooves BGa formed on the inner circumferential surface of the main body portion BR1a and radial grooves BGb formed on the surface of the flange portion BR1b that faces the thrust disk TD. These axial grooves BGa and radial grooves BGb are connected to each other. In this embodiment, the bearing BR1 has multiple grooves BG, but it may also have at least one groove BG.

[0089] As described above, the liquid supplied to the inner housing BH cools and lubricates the bearing BR1 mounted in the inner housing BH. By forming the groove BG in the bearing BR1, the liquid can actively pass through the gap between the bearing BR1 and the rotating shaft 2, more efficiently lubricating and cooling the bearing BR1.

[0090] In one embodiment, a groove (not shown) corresponding to the groove BG may be formed on the surface of the thrust disk TD facing the bearing BR1. This configuration allows the liquid to flow more efficiently through the gap between the flange portion BR1b of the bearing BR1 and the thrust disk TD.

[0091] A portion of the liquid flowing through the annular flow passage 13 passes through the gap between the impeller 1 and the casing cover 30 and is introduced into the space in which the bearing BR2 is disposed. This liquid comes into contact with the bearing BR2 to cool and lubricate it. Therefore, in one embodiment, a groove (not shown) corresponding to the groove BG may be formed in the bearing BR2.

[0092] As shown in Figure 2, the inner housing BH is disposed to surround the disc holder DH. Therefore, the liquid that passes through the gap between the flange portion BR1b and the thrust disc TD passes through the gap between the disc holder DH and the inner housing BH. The liquid then passes through the gap between the disc holder DH and the inner casing 4 and is returned to the pump P.

[0093] Fig. 15 is a diagram showing communication holes having a greater number than the number of anti-rotation pins. Fig. 16 is a diagram showing flow grooves formed in a casing cover. In the embodiment shown in Fig. 15, the number of communication holes 50 is greater than the number of anti-rotation pins WP. Therefore, part of the liquid returned to the pump P side passes through communication holes 50 that do not have anti-rotation pins WP inserted therein.

[0094] 16, the casing cover 30 has a communication groove 110 formed in its inner surface 30a. The inner surface 30a of the casing cover 30 faces the impeller 1. The communication groove 110 communicates with the communication hole 50 formed in the impeller 1 and extends toward the low-pressure side flow path of the annular flow path 13.

[0095] Therefore, the liquid that has passed through the communication hole 50 flows through the circulation groove 110 and is returned to the low-pressure side flow path of the annular flow path 13. In this way, by forming the communication hole 50 and the circulation groove 110, a circulation flow of liquid can be created between the motor M side and the pump P side. By creating such a circulation flow, gas remaining in the pump P immediately after starting operation of the pump P and gas that is mixed into the pumped liquid during self-priming operation can be efficiently discharged.

[0096] The above-described embodiments have been described for the purpose of enabling a person of ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments would be obvious to a person skilled in the art, and the technical concept of the present invention may be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope in accordance with the technical concept defined by the claims. [Explanation of symbols]

[0097] 1 impeller 1a Radial groove 2 rotation axes 2a Fastening hole 3 Casing body 4 Inner casing 4a Through-flow channel 5A Suction side liquid tank 5B Discharge side liquid tank section 10 Intake port 12 Suction passage 13 Annular flow path 14 Discharge flow path 15 Outlet 20 Return flow path 30 Casing cover 40 Bracket 50 Communication hole 100 Tank Cover 110 Distribution groove P pump Medium motor PA pump device PC pump casing SP suction piping DP discharge piping Sa, Sb sealing material CH1 gas-liquid separation chamber LCHa liquid chamber GCHa gas chamber CH2 gas-liquid separation chamber LCHb liquid chamber GCHb gas chamber B Bolt BH inner housing BHa communication channel PP Locating Pin BR1,BR2 bearings BR1a main body BR1b flange RE Rotation Element BG Groove BGa axial groove BGb Radial groove CL center axis MS drive shaft MC magnetic coupling MCa motor side magnet MCb pump side magnet CP Cover Plate CCA coupling case CCA-1 outer cylinder CCA-2 inner cylinder part CCA-2a insertion hole CCO Coupling Cover P Anti-detachment pin DH Disc Holder DHa connection hole DHb flat area WP anti-rotation pin SF Shrink Fit RC storage recess TD Thrust Disc TDa Anti-rotation part

Claims

1. A pump, A rotation axis; an impeller attached to the rotating shaft; a pump casing that houses the impeller and forms an annular flow path between the impeller and the pump casing; a suction-side liquid tank portion that communicates with a suction flow path connected to the annular flow path and has a gas-liquid separation chamber.

2. the pump includes a discharge-side liquid tank portion that is in communication with a discharge flow path connected to the annular flow path and has a gas-liquid separation chamber; 2. The pump according to claim 1, wherein the suction-side liquid tank portion has a gas-liquid separation chamber that is larger than the discharge-side liquid tank portion.

3. The pump according to claim 2 , wherein the suction-side liquid tank portion and the discharge-side liquid tank portion are integrally formed.

4. The pump according to claim 3 , wherein the suction-side liquid tank portion and the discharge-side liquid tank portion are formed in the pump casing.

5. The pump according to claim 1 , further comprising a tank cover that closes the suction-side liquid tank portion.

6. The pump according to claim 1 , wherein the suction passage has a cross-sectional area equal to or greater than that of the discharge passage connected to the annular passage.

7. The pump according to claim 1 , wherein the suction-side liquid tank portion is disposed downstream of the suction flow path in a flow direction of liquid flowing backward through the pump.

8. 1. A pump device comprising: A pump according to any one of claims 1 to 7; a motor that drives the pump.

9. The pump device a drive shaft connected to a rotating element of the motor; a magnetic coupling that transmits the rotational force of the drive shaft to the rotation shaft, The magnetic coupling is a motor-side magnet fixed to the drive shaft; a pump-side magnet fixed to the rotating shaft, 9. The pump device according to claim 8, wherein the motor-side magnet and the pump-side magnet are arranged in a straight line along a central axis extending parallel to the rotation shaft and the drive shaft.

10. The pump device a coupling case that accommodates the pump-side magnet; a coupling cover that closes an open end of the coupling case; a detachment prevention pin that prevents the coupling cover from being detached from the coupling case, The pump device according to claim 9, wherein the anti-detachment pin is inserted into a fastening hole formed in the rotating shaft.

11. The pump device a disk holder fixed to the rotating shaft; A communication hole formed in the impeller; a locking pin connected to the disc holder, The pump device according to claim 8 , wherein the anti-rotation pin is inserted into the communication hole to fix the disk holder to the impeller.

12. the pump device includes a thrust disk accommodated in an accommodating recess of the disk holder; 12. The pump device according to claim 11, wherein the thrust disk has a rotation prevention portion formed on an outer circumferential surface thereof.

13. the pump casing includes a casing cover disposed opposite the impeller, The pump device according to claim 11, wherein the casing cover has a flow groove that communicates with the communication hole and extends toward the low-pressure side flow passage of the annular flow passage.

14. the pump device includes a bearing that rotatably supports the rotary shaft, 9. The pump device according to claim 8, wherein the bearing has a groove that allows passage of liquid that has entered a gap between the rotating shaft and the bearing.

15. The bearing is a main body extending parallel to the rotation axis; a flange portion connected to the main body portion, The groove is an axial groove formed in the body portion; 15. The pump apparatus of claim 14, further comprising a radial groove formed in the flange portion.

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