Submersible pump with air pipe and its equipment

Abstract

To make it possible to maintain an operation at a rated speed and inhibit repeated starts and stops of a pump even if the suction port side water level is equal to or less than a lowest water level allowing an all-volume pumping-out operation.SOLUTION: A horizontal-shaft submersible mixed flow pump 1 has a discharge port 65 disposed to face an impeller 32, and inspired air is supplied from the discharge port 65 formed in a suction cover 5. When the water level decreases, air is supplied from the discharge port 65 at a time right before entry to an air-water mixing discharge operation. Water in a casing 2 of the submersible mixed flow pump 1 instantaneously drops so that the impeller 32 stops causing discharge of water, and thus the intra-pump pressure drops and a flap valve 4 is closed by its own weight and the external water pressure, so as to start an aerial stand-by operation in which the impeller 32 is exposed into air (a motor 3 maintains a rotary drive state at a rated speed). The oscillation is small and the burden on the motor 3 is small. If the water level increases during the aerial stand-by operation, then the air from the discharge port 65 is blocked to cause an instantaneous transition to an all-volume pumping-out operation.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a submersible pump with an air pipe and its equipment. More specifically, for example, in a submersible pump fixedly arranged on the door body of a sluice provided across a river or the like, even when the water level on the suction side is below the lowest water level at which full-capacity drainage operation is possible, the operation at the rated rotational speed is maintained, and the present invention relates to a submersible pump with an air pipe and its equipment that enables suppression of repeated startup and stop of the pump.

Background Art

[0002] In a submersible pump, when the water level on the suction side drops below a certain level, air is sucked from the suction port into the pump casing, resulting in a gas-liquid mixed operation, a decrease in the drainage volume, and an increase in vibration and noise. Therefore, when the water level on the suction side drops below a certain level, the operation of the pump is temporarily stopped, and then the pump is restarted when the inflow volume increases and the water level on the suction side rises. In this way, if the pump is frequently turned on and off according to the water level on the suction side, the operation management becomes complicated, the frequency of starting and stopping the pump becomes complicated, and the burden on the submersible motor and starter increases, which is not preferable.

[0003] In order to avoid the above-described air-water mixed operation, the vertical shaft pump described in Patent Document 1 is provided with a float that moves up and down according to the water level on the water intake side. When the water level drops below the lowest water level, the air valve is opened to suck in air, causing the water in the bellmouth to fall and performing air operation. The prior standby operation pump described in Patent Document 2 is provided with a compressed air supply passage in the main shaft of the pump, which is a vertical shaft, in order to prevent abnormal vibration and noise when switching from drainage operation to holding operation. This compressed air supply passage discharges compressed air from the inlet side of the impeller, quickly drops the residual water in the discharge pipe into the water supply well, and shortens the holding operation in which full-speed operation is possible regardless of the water level in the pump well. Furthermore, when the water level on the suction port side of the submersible pump described in Patent Document 3 drops, air is sucked through a notch provided in the suction cover or an air intake pipe, and air-water mixed operation is performed to reduce the drainage volume. Even when the water level on the suction port side is below the water level during full-capacity drainage operation, operation at the rated rotational speed is maintained, and repeated on / off operation of the pump is suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the pump described in Patent Document 1 is a fixed vertical shaft pump in which the pump body is fixed to a structure such as a slab, and is not applicable to a horizontal shaft or an inclined shaft submersible pump that is horizontal or inclined at a predetermined angle from the horizontal. Therefore, it cannot be applied to a movable horizontal shaft submersible pump such as a gate pump (Trademark Registration No. 2585973, general name is "pump gate") in which a submersible pump is mounted on a gate body of a water gate or a sluice gate and the two are integrated. Similarly, the prior standby operation pump described in Patent Document 2 is also a fixed vertical shaft pump in which the pump body is fixed to a structure such as a slab, and is not assumed for a horizontal shaft or an inclined shaft submersible pump, and cannot be applied to a gate pump which is a movable submersible pump. The submersible pump applied to the pump gate described in Patent Document 3 is a horizontal shaft submersible pump, and introduces air when the water level falls below a certain level. However, during the air-water mixed operation, the vibration and noise increase, and the drainage volume also decreases. Further, when the water level further drops and the pump is operated at the rated rotational speed while the drainage volume is lost, it shifts from the air-water mixed operation to the air standby operation. This air-water mixed operation should preferably be as short as possible or practically non-existent. The present invention has been invented against the above background and achieves the following objects.

[0006] An object of the present invention is to provide a horizontal shaft or inclined shaft submersible pump with an air pipe and its equipment without air-water mixed operation, using a mechanical air shut-off valve that can open and close the valve with a float. Another object of the present invention is to provide a horizontal shaft or inclined shaft submersible pump with an air pipe and its equipment that enables operation at the rated rotational speed even when the water level on the suction side is below the lowest water level at which full volume drainage operation is possible, and suppresses repeated startup and stop of the pump.

Means for Solving the Problems

[0007] In order to solve the above problems, the present invention takes the following means. That is, the submersible pump with an air pipe of the first aspect of the present invention a casing having a suction port on one side and a discharge port on the other side, an electric motor fixed in the casing for rotational drive, A lateral direction in which the axis of the output shaft of the motor is horizontal, or an impeller that is arranged with the axis inclined at a predetermined angle from the horizontal and is connected to the output shaft and driven to rotate, A suction cover fixed to the casing and having an opening for sucking in fluid In a submersible pump comprising: An air pipe for sucking air into the submersible pump from a discharge port disposed upstream of the impeller and within the submersible pump, Comprising an air on-off valve control mechanism for supplying or blocking air to the air pipe, The air on-off valve control mechanism An air on-off valve for supplying or blocking air to the air pipe, A float that moves up and down by buoyancy according to the water level on the suction port side, And a lever mechanism that transmits the up and down movement of the float to the air on-off valve to control the opening and closing of the air on-off valve, The timing of the water level when opening and closing the air on-off valve is different when the water level rises and when the water level falls, The lever mechanism has one end fixed to the float, and the other end is provided with the air on-off valve that serves as a lid for opening and closing. It swings around a swing axis and has a position that selectively locks at two different positions when the water level rises and when the water level falls, and has a float wobbling prevention mechanism, The float wobbling prevention mechanism The float (86) fixed to one end, the air Open and close A rod body (85) that swings around a swing axis (86) composed of the on-off valve fixed to the other end, A spring case (201) that swings together with the rod body and is provided with a spring (204), A first concave portion (202a) of a locking portion formed on the fixed cam plate (201), and a steel ball or roller (203) that is urged by the spring (204) and fits into the first concave portion (202a) to form a first locking portion that locks at the position when the water level rises, It is a second recess (202b) of a locking portion formed in the cam plate (201), and is composed of a second locking portion that locks at a position when the water level drops, which is composed of the steel ball or roller (203) urged by the spring (204) and fitted into the second recess (202b).

[0008] The submersible pump with an air pipe according to the second aspect of the present invention is the submersible pump with an air pipe according to the first aspect of the present invention, wherein the submersible pump with an air pipe is an underwater diagonal flow pump in which a flow path of a fluid driven by the impeller is inclined with respect to the axial center, or an underwater axial flow pump in which the flow path of the fluid is in the axial direction. The submersible pump with an air pipe according to the third aspect of the present invention is the submersible pump with an air pipe according to the first or second aspect of the present invention, wherein the discharge port is characterized in that the central axis of the discharge port is arranged parallel to the axial center.

[0009] The submersible pump with an air pipe according to the fourth aspect of the present invention is the submersible pump with an air pipe according to the 1 or 2 present invention, wherein the discharge port is arranged facing the impeller. The submersible pump with an air pipe according to the fifth aspect of the present invention is the submersible pump with an air pipe according to the 1 or 2 present invention, wherein the air pipe is connected to the suction cover or the casing.

[0010] The submersible pump facility with an air pipe according to the sixth aspect of the present invention is the submersible pump facility with an air pipe according to the 1 to 5 present invention, wherein the submersible pump with an air pipe is mounted on a floodgate or a sluice gate that crosses a river or a waterway.

Advantages of the Invention

[0012] The submersible pump with an air pipe and its equipment of the present invention controls the air valve by a mechanical float-type automatic air opening and closing valve control mechanism that can open and close the air valve with a float, enabling an instantaneous transition from full-capacity drainage operation to air standby operation or from air standby operation to full-capacity drainage operation. Specifically, when the water level on the suction side drops below the lowest water level at which full-capacity drainage operation is possible, air is supplied from the air pipe, allowing for an instantaneous transition from full-capacity drainage operation to air standby operation. If the water level on the suction side rises during air standby operation, the air supply is cut off, enabling an instantaneous transition from air standby operation to full-capacity drainage operation. Therefore, the air-water mixed operation can be terminated in a short time or eliminated, reducing vibration while maintaining operation at the rated rotational speed and suppressing repeated startup and shutdown of the pump. Furthermore, the float-type automatic air opening and closing valve control mechanism that controls the opening and closing of the air valve is equipped with a float anti-wobbling mechanism, enabling reliable and stable opening and closing of the air valve.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0014] [Axial-flow pump 1 in the first embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an axial-flow pump 1 in the first embodiment of the present invention. As shown in FIG. 1, the axial-flow pump 1 in the first embodiment of the present invention is fixed to a gate or sluice door body 100 provided across a river, waterway, sewer, etc. with bolts or the like via a bracket 101 or the like. Note that the structure may be such that the flange portion of the casing 2 of the axial-flow pump 1 is directly fixed to the gate or sluice door body 100. As described above, these structures are those in which an underwater pump is mounted on a gate (gate) and the two are integrated, and are called gate pumps (trademark registration No. 2585973, general name is "pump gate").

[0015] The axial-flow pump 1 in the present embodiment is a so-called axial-flow pump in which the flow of the fluid discharged from the impeller sends the fluid in an oblique direction from the center line of the output shaft 31. The axial-flow pump 1 has a casing 2 having a suction port 21 (on the left side in FIG. 1) on one side and a discharge port 22 on the other side (on the right side in FIG. 1). Inside the casing 2, an electric motor 3 for rotationally driving the impeller 32 is fixed. An output shaft 31 is attached to the electric motor 3 of the axial-flow pump 1 on the suction port 21 side, the impeller 32 is fixed to the output shaft 31, and the rotational torque of the electric motor 3 is transmitted to the impeller 32. Adjacent to the downstream side of the impeller 32, a guide vane 33 is fixed between the inner peripheral surface of the casing 2 and the outer peripheral surface of the oil chamber 34. The guide vane 33 guides the water pumped up by the impeller 32.

[0016] A flap valve 4 supported to be openable and closable is disposed on the discharge port 22 side of the casing 2. The flap valve 4 is swingably attached by a fulcrum 4a disposed on the upper part of the casing 2. When the discharge pressure of water from the discharge port 22 is low, the flap valve 4 closes by its own weight, and when the discharge pressure of water becomes high, it opens about the upper fulcrum 4a, enabling the discharge of water from the discharge port 22. A suction cover 5 for smoothly guiding water to the suction port 21 is fixed to the suction port 21 of the casing 2 on the opposite side of the discharge port 22. The opening 53 at the tip of the suction cover 5 faces obliquely downward from the horizontal (angle of attack θ), and river water (or water in a waterway) on the upstream side is sucked in from this opening 53.

[0017] As shown in Fig. 1, in the underwater diagonal flow pump 1 of this embodiment, the axis 311 of the output shaft 31 is arranged substantially horizontally. Assuming that the height from the bottom surface 102 of the water channel to the upper edge (the lower surface of the suction guide plate 511) 531 of the opening 53 of the suction cover 5 is Y1, and the height from the bottom surface 102 of the water channel to the lower end of the impeller 32 is Y3, Y1 is arranged at a position higher than Y3. Note that the upper edge 531 of the opening 53 of the suction cover 5 is arranged at a position lower than the axis 311 of the output shaft 31. The lower edge 532 of the opening 53 is at a height of Y2 from the bottom surface 102 of the water channel. When the water level is at or below the water level Y2 of the lower edge 532 of the opening 53, since it is at a position lower than the height Y3 to the lower end of the impeller 32, the underwater diagonal flow pump 1 does not suck in river water (or water in the water channel). Here, the "air valve opening and closing water level" shown on the left side of Fig. 1 will be described. During the air standby operation, when the water level rises and the water level reaches 60% or more of the height of the impeller 32, the impeller 32 can discharge the water in the casing 2 by itself, and the full amount drainage operation becomes possible. Until the water level reaches this level in the vicinity during the water level rise, the impeller 32 does not discharge water by itself, so the air standby operation is carried out. And when the water level reaches 60% of the impeller 32, the air valve 89 closes and blocks the air supplied to the underwater diagonal flow pump 1 through the air pipe 64. Therefore, even if the impeller 32 discharges water, air is not supplied, and it can instantly shift from the air standby operation to the full amount drainage operation. Therefore, the "air valve opening and closing water level" shown on the left side of Fig. 1 is the water level at which the air opening and closing valve opens and closes, and is approximately 60% of the water level of the impeller 32. The full amount drainage operation and the air standby operation are switched at this opening and closing water level.

[0018] Float type automatic air opening and closing valve control mechanism 80 The underwater diagonal flow pump 1 of the first embodiment controls the supply and cutoff of air into the underwater diagonal flow pump 1 by means of a float-type automatic air valve control mechanism 80 mounted on the underwater diagonal flow pump 1. FIG. 2 is an enlarged cross-sectional view of the float-type automatic air valve control mechanism 80. The float-type automatic air valve control mechanism 80 is a mechanical opening and closing mechanism in which the float 84 moves up and down according to the water level, and the air valve is automatically opened and closed by this up and down movement. On the upper part of the suction cover 5, a dust removal cover 81 in the shape of a box with a space surrounded by an upper plate and side plates is fixed. The dust removal cover 81 is not an essential component for the basic function of the float-type automatic air valve control mechanism 80, but protects the air valve 89 and the like from the flow of dust and the like. A plurality of through air holes 83 are formed in the upper part of the side plate 82 of the dust removal cover 81. Therefore, when the water level drops, outside air can freely enter the dust removal cover 81 from the outside. In addition, a through hole (not shown) is formed in the dust removal cover 81 so that the water in the river (or waterway) on the water intake side can also freely enter. The water level in the dust removal cover 81 is the same as the water level of the river (or waterway).

[0019] The float 84 is a hollow metal sphere that moves up and down according to the water level of the river (or water channel). One end of a rod 85 is fixed to the sphere of the float 84 in the radial direction thereof. The other end of the rod 85 is swingably attached to a flange 87 by a swing shaft 86. The flange 87 is fixed to an attachment pipe 88 which is an air pipe. The lower end of the attachment pipe 88 is connected to the upper end of an L-shaped air pipe 64. This air pipe 64 is fixed to the suction cover 5. The upper end of the attachment pipe 88 is open, and an air valve 89 is arranged to cover this opening. One end of the air valve 89 is fixed to the end of the above-mentioned rod 85. Therefore, when the float 84 moves up and down according to the water level of the river (or water channel), the air valve 89 opens and closes the opening at the upper end of the attachment pipe 88 according to this up and down movement. The lower end of the attachment pipe 88 is connected to the upper end of the air pipe 64, and air conducts between them. The other end of the air pipe 64 has one end of a discharge port 65 which is a pipe fixed thereto. The central axis of the discharge port 65 is arranged parallel to the axial direction of the output shaft 31. Also, the discharge port 65 is arranged facing the impeller 32.

[0020] Air is sucked into the inside of the casing 2 from the tip of this discharge port 65 through the attachment pipe 88 and the air pipe 64. Since this float-type automatic air opening / closing valve control mechanism 80 uses a float 84 that moves up and down by the buoyancy of water, it has the advantage that the air valve 89 can be automatically opened and closed according to the water level of the river (or water channel) without using an electric control device. The air, which is the atmosphere, is sucked into the casing 2 from the discharge port 65 through the attachment pipe 88 and the air pipe 64 by the suction force (negative pressure) during the operation of the underwater diagonal flow pump 1. That is, the discharge port 65 is piped to the air pipe 64 attached to the suction cover 5. As shown in FIG. 1, the central axis of the discharge port 65 which is a pipe is arranged parallel to the axis 311 of the output shaft 31 of the underwater diagonal flow pump 1. More precisely, the central axis of the discharge port 65 is arranged at a position lower than the axis 311 of the output shaft 31. That is, the discharge port 65 is arranged facing the impeller 32 at a position lower than the axis 311. As a result, the air sucked from the discharge port 65 is expected to be sucked in almost uniformly up and down in the central direction of the impeller 32 while slightly upward due to the buoyancy of the air.

[0021] Operation of the float type automatic air opening and closing valve control mechanism 80 Summarizing the above operations, the control is as follows. For example, when the driver turns on the switch (not shown) of the motor 3 of the underwater diagonal flow pump 1 to turn it on, the motor 3 starts to rotate, sucking up the upstream river water (or canal water) and flowing it to the downstream side. For example, when the water level is dropping and during the full-capacity drainage operation, the float 84 in the trash removal cover 81 is located at the uppermost position in the water due to its buoyancy, so the air valve 89 is closed. Therefore, even if the water level on the suction side drops, as shown in Fig. 1, if the water level on the suction side is higher than the "air valve opening / closing water level", the air valve 89 is in the closed state, so no air is sucked in from the air pipe 64 and no air is sucked in from the opening 53 either. Thus, the inside of the suction cover 5 and the casing 2 are filled with water. Therefore, the underwater diagonal flow pump 1 continues to operate in full-capacity drainage at the rated rotational speed. When the water level reaches the "air valve opening / closing water level" position below the water level of the "full-capacity drainage operation", the float 84 drops, opening the air valve 89 and supplying air to the underwater diagonal flow pump 1 through the air pipe 64. Due to this supply of air, the underwater diagonal flow pump 1 immediately enters the air standby operation mode. As a result, the water inside the suction cover 5 and the casing 2 of the underwater diagonal flow pump 1 instantly drops, and the impeller 32 stops discharging water. Therefore, the pressure inside the pump drops, the flap valve 4 closes due to its own weight and the pressure of the outside water, and the impeller 32 is exposed to the air for air standby operation (the motor 3 continues to rotate in the rotation drive state at the rated rotational speed). Therefore, the vibration is small and the operation with less burden on the motor 3 continues.

[0022] Also, when the water level is rising and in the water level range of "air standby operation", the air valve 89 is open, and since the impeller 32 has not reached the water level at which it can discharge water, the air standby operation continues. Then, as the water level further rises and the suction side water level reaches the "air valve opening and closing water level" (see Fig. 1), the air valve 89 is closed to cut off the air from the air pipe 64 to the submersible diagonal flow pump 1. As a result, even if the impeller 32 discharges water, air is not supplied into the submersible diagonal flow pump 1, so the submersible diagonal flow pump 1 shifts from the air standby operation to the full discharge operation at the rated rotational speed. Fig. 3 is a graph showing the current (A) and vibration (note: the combined vibration in the X direction, Y direction, and Z direction) (μm) of the motor 3 of the submersible diagonal flow pump 1 (pump diameter: 300 mm) according to the present embodiment of the present invention. In Fig. 3, after raising the suction side water level from 200 mm to 600 mm, it is then lowered to 200 mm. As shown in Fig. 3, when the water level rises, it instantaneously shifts from the air standby operation to the full discharge operation, and when the water level drops, it instantaneously shifts from the full discharge operation to the air standby operation, and no air-water mixed operation occurs, or for a short time, the fluctuations in the current (A) and the vibration (μm) become small.

[0023] Fig. 4 is a graph showing the current (A) and vibration (note: the combined vibration in the X direction, Y direction, and Z direction) (μm) of the motor 3 of a conventional submersible diagonal flow pump (pump diameter: 300 mm) without an air pipe. As shown in Fig. 4, in the conventional submersible diagonal flow pump, air is sucked in from above the upper edge 531 of the opening 53, causing air-water mixed operation. Therefore, it takes time to switch from the air standby operation to the full discharge operation and from the full discharge operation to the air standby operation, and the vibration is also large. In contrast, for the submersible diagonal flow pump 1 according to the first embodiment of the present invention, as shown in Fig. 3, no air-water mixed operation occurs, or for a short time, the switching from the air standby operation to the full discharge operation and the switching from the full discharge operation to the air standby operation are performed instantaneously, and the vibration is also small.

[0024] 〔Submersible Diagonal Flow Pump 1 of the Second Embodiment〕 Figure 5 shows the underwater diagonal flow pump 1 of the second embodiment. The underwater diagonal flow pump 1 (not shown) of the second embodiment has the same structure as that of the first embodiment, but only the structure of the float-type automatic air valve control mechanism 90 is changed. Figure 5 is an enlarged cross-sectional view of this float-type automatic air valve control mechanism 90. In the float-type automatic air valve control mechanism 80 (Figure 2) of the first embodiment, when the water level fluctuates up and down unstably near the water level at which the air valve 89 is opened and closed, the opening and closing of the air valve 89 may be frequently performed and become unstable. The float-type automatic air valve control mechanism 90 has a "float wobbling prevention mechanism 200" for reliably and stably controlling the opening and closing timing of the air valve 89.

[0025] [Float wobbling prevention mechanism 200] The float wobbling prevention mechanism 200 is locked (a kind of temporary fixing) at either one of two positions: the position of the "air valve closing water level" that closes the air valve 89 according to the water level, or the position of the "air valve opening water level" that opens the air valve 89. With this float wobbling prevention mechanism 200, the water level (timing) at which the air valve 89 is opened and closed can be made different when the water level rises and when the water level drops. Hereinafter, this float wobbling prevention mechanism 200 will be described. In the first pattern (the type in which both the rod body 85 and the spring case 205 move remotely), the cam plate 201 constituting the float wobbling prevention mechanism 200 is fixedly arranged on the flange 87 (see Figure 2), the dust removal cover 81, etc. by a fixing member (not shown). The cam plate 201 has an arc surface centered on the swing axis 86 of the rod body 85. Two hemispherical depressions, an upper recess 202a and a lower recess 202b, are formed on this arc surface.

[0026] The diameters of the upper concave portion 202a and the lower concave portion 202b are substantially the same as the diameter of the steel ball (or roller) 203, and the steel ball (or roller) 203 selectively fits into the upper concave portion 202a or the lower concave portion 202b. The steel ball (or roller) 203 is biased toward the cam plate 201 by a coil spring 204. The coil spring 204 is housed in a hole of a spring case 205 having one end opened. The spring pressure of the coil spring 204 can be adjusted by an adjustment bolt 206 screwed into the other end of the spring case 205. The spring case 205 is fixed to a rod 85 that swings together with the float 84. Therefore, the spring case 205 also swings together with the rod 85. Note that the mechanism is not limited to this, and a second pattern (a type in which both the rod 85 and the cam plate 201 swing together) may be used. In this mechanism, the cam plate 201 constituting the float wobbling prevention mechanism 200 is fixed to the rod 85 that swings together with the float 84. Therefore, the cam plate 201 also swings together with the rod 85.

[0027] The cam plate 201 is formed with an arc surface centered on the swing axis 86 of the rod body 85. On this arc surface, an upper recess 202a and a lower recess 202b, which are two hemispherical depressions, are formed. The diameters of the upper recess 202a and the lower recess 202b are substantially the same as the diameter of the steel ball (or roller) 203, and the steel ball (or roller) 203 selectively fits into the upper recess 202a or the lower recess 202b. The steel ball (or roller) 203 is biased toward the cam plate 201 side by a coil spring 204. The coil spring 204 is housed in a hole of a spring case 205 with one end open. The spring pressure of the coil spring 204 can be adjusted by an adjustment bolt 206 screwed into the other end of the spring case 205. In addition, in the mechanism of the second pattern, the spring case 205 is fixedly arranged on the flange 87 (see FIG. 2), the dust cover 81, etc. by a fixing member (not shown). Further, in the third pattern, compared with the above two patterns, the basic structure is the same, but two spring cases 205 and cam plates 201 are provided for the upper part and the lower part respectively. Specifically, the upper cam plate is formed with an upper recess 202a which is a hemispherical depression on the arc surface, and the lower cam plate is formed with a lower recess 202b which is a hemispherical depression on the arc surface. Corresponding to this, using an upper spring case and a lower spring case, two positions, namely the position of the "air valve closing water level" for closing the air valve 89 according to the water level and the position of the "air valve opening water level" for opening the air valve 89, are locked (a kind of temporary fixing). With this configuration, the positions of the "air valve closing water level" and the "air valve closing water level" can be adjusted respectively. Therefore, it is a structure that facilitates the adjustment of the float wobbling prevention mechanism 200 at the place where the pump (the underwater diagonal flow pump 1) is installed, that is, at the site.

[0028] Operation of the float wobbling prevention mechanism 200 In the structures of the above first to third patterns, since the operations of the float 84, the rod 85, the air valve 89, the cam plate 201 (201a, 201b), and the spring case 205 (205a, 205b) are basically the same, the operation in the case of the first pattern will be described. When the water level on the suction port side drops from the water level of the "full drainage operation" and becomes below the "air valve opening water level" (see Fig. 5), it is necessary to open the air valve 89 to avoid the air-water mixed operation. At this time, even if the water level fluctuates slightly and the float 84 moves up and down somewhat accordingly, since the steel ball (or roller) 203 is fitted into the upper concave portion 202a of the float wobbling prevention mechanism 200, the steel ball (or roller) 203 will not escape from the upper concave portion 202a. However, when the float 84 further descends and the buoyancy becomes smaller, when the condition of "the resistance (frictional force, inclination angle) of the wobbling prevention mechanism < (│buoyancy of the float - self-weight of the float 84│)" is satisfied, due to the self-weight of the float 84, the steel ball (or roller) 203 escapes from the upper concave portion 202a and the air valve 89 opens. That is, even if there is a slight fluctuation in the water level, the air valve 89 will not open until the "air valve opening water level", so there will be no unstable air-water mixed operation. This "air valve opening water level" is set to operate stably when the water level drops and is the water level at which the underwater diagonal flow pump 1 is switched from the full drainage operation to the air standby operation. Therefore, this "air valve opening water level" is preset according to the structure and function of the underwater pump.

[0029] Conversely, during the air standby operation, if the water level rises and exceeds the "air valve closed water level", it is necessary to close the air valve 89 to avoid the air-water mixed operation. At this time, similar to when the water level drops, even if the water level fluctuates slightly up and down and the float 84 moves up and down somewhat accordingly, since the steel ball (or roller) 203 is fitted into the lower concave portion 202b of the float sway prevention mechanism 200, the steel ball (or roller) 203 will not escape from the lower concave portion 202b. However, if the buoyancy of the float 84 further increases and the condition of "the resistance (frictional force, inclination angle) of the anti-sway mechanism < (|the buoyancy of the float - the self-weight of the float 84|)" is satisfied, the steel ball (or roller) 203 will escape from the lower concave portion 202b due to the buoyancy of the float 84, closing the air valve 89. That is, even if there are some fluctuations in the water level before and after the opening and closing of the air valve 89, the air valve 89 cannot be closed until the "air valve closed water level", so an unstable air-water mixed operation will not occur and the air standby operation can be performed. This "air valve closed water level" is set to operate stably when the water level rises and is the water level at which the underwater diagonal flow pump 1 is switched from the air standby operation to the full drainage operation. Therefore, this "air valve closed water level" is preset according to the structure and function of the underwater pump.

[0030] As can be understood from the above description, "the float sway prevention mechanism 200 can make the water levels (timings) at which the air valve 89 is opened and closed different when the water level rises and when the water level drops." By this, the following controls 1 and 2 can be achieved, and the effect of suppressing the repeated start and stop of the drainage operation (full drainage operation and air standby operation) of a wide range of pumps that avoid the air-water mixed operation can be expected. 1. When the water level drops, the operation can be performed until the "air valve open water level" at which air is not sucked in from the suction cover with a water level lower than the air valve opening and closing water level (about 60% water level of the impeller 32) in the first embodiment for the "full drainage operation" water level. By supplying air at the "air valve open water level", the control can be achieved to instantly shift from the full drainage operation to the air standby operation. 2. When the water level rises, it is assumed that the air-water mixed operation cannot be reliably avoided at the air valve opening and closing water level (about 60% water level of the impeller 32) in the first embodiment. Therefore, by closing the air valve at a lower water level to cut off the air, an "air valve closing water level" (about 55% water level of the impeller 32 in this embodiment) is set that can reliably avoid the air-water mixed operation. As a result, compared with the air valve opening and closing water level (about 60% water level of the impeller 32) in the first embodiment, the "full discharge operation possible water level" (about 60% water level of the impeller 32) in Fig. 5 can surely enable the "full discharge operation", and by cutting off the air at the "air valve closing water level", control can be performed to instantaneously shift from the air standby operation to the full discharge operation.

[0031] [Submersible axial flow pump 10 of the third embodiment] Fig. 6 shows the submersible axial flow pump 10 of the third embodiment. The submersible axial flow pump 10 is a pump with a structure different from those of the first and second embodiments described above. The submersible axial flow pump 10 is a pump that sends fluid in the direction of the axis 311 of the output shaft 31, and has a casing 2 with a suction port 21 on one side (the left side in Fig. 6) and a discharge port 22 on the other side (the right side in Fig. 6). Inside the casing 2, a motor 3 for rotational drive is fixed. To the motor 3, an output shaft 31 is attached on the discharge port 22 side, an impeller 32 is fixed to the output shaft 31, and the rotation of the motor 3 is transmitted to the impeller 32. A guide vane 33 is fixed between the inner circumference of the casing 2 and the outer circumference of the oil chamber 34 on the suction port 21 side (upstream side) of the impeller 32. The guide vane 33 guides the water pumped up by the impeller 32.

[0032] A flap valve 4 that is supported on the casing 2 so as to be openable and closable on the discharge port 22 side is attached. When the discharge pressure of water from the discharge port 22 is low, the flap valve 4 closes by its own weight, and when the discharge pressure of water increases, it opens around the upper fulcrum 4a, enabling the discharge of water from the discharge port 22. A suction cover 5 for smoothly guiding water to the suction port 21 is fixed to the suction port 21 of the casing 2. As shown in FIG. 6, the suction cover 5 is formed of an upper plate, side plates, etc. from one or more plate materials. In the axial flow pump 10 in water of the third embodiment, a float type automatic air opening and closing valve control mechanism 90 that operates on the same principle as the second embodiment described above is arranged. It consists of a float 84, a rod body 85, a remote control shaft 86, an air valve 89, a float wobbling prevention mechanism 200, an air pipe 64, a discharge port 65, etc.

[0033] Air, which is the atmosphere, is sucked into the casing 2 from two discharge ports 65 by the suction force during the operation of the axial flow pump 10 in water, causing the air pipe 64 connected to the attachment pipe 88 to be bifurcated into two, and then being sucked from the two discharge ports 65 through branch pipes (not shown). The two discharge ports 65 are respectively arranged in the suction cover 5 on the left and right of the outer periphery of the electric motor 3, that is, sandwiching both sides of the electric motor 3. These discharge ports 65 are piped to the air pipe 64 fixed to the suction cover 5. The central axis of the discharge port 65 is arranged parallel to the axis 311 of the output shaft 31 of the axial flow pump 10 in water. Exactly, the central axis of the discharge port 65 is arranged at a position lower than the axis 311 of the output shaft 31. That is, the discharge port 65 is arranged at a position lower than the axis 311 so as to face the front of the impeller 32. The operation of the float type automatic air opening and closing valve control mechanism 90 of the axial flow pump 10 in water of the third embodiment and the full - volume drainage operation and air - medium standby operation of the axial flow pump 10 in water that are interlocked therewith are substantially the same as those of the axial flow pump 1 in water of the second embodiment, and the description thereof is omitted.

[0034] [Other Embodiments] The embodiments of the present invention have been described above, but the present invention is not limited to these examples. For example, in the above-described diagonal flow pump 1 and axial flow pump 10 in water, the output shaft 31 of the motor 3 and the axis of the impeller 32 connected thereto are arranged horizontally in the lateral direction. However, the axis may be inclined from the horizontal. Further, the shape of the suction cover 5 of the above-described diagonal flow pump 1 and axial flow pump 10 in water varies depending on the structure of the pump in water. Therefore, the suction cover 5 referred to in the present invention is not limited to the cover on the suction side of the pump body, but is a concept including the main body portion. Furthermore, in the above-described embodiment, the vertical movement of the float 84 directly drives the air valve 89 with the rod body 85. However, instead of the rod body 85, the vertical movement of the float 84 may open and close the air valve 89 via a link mechanism. For example, a link mechanism having a plurality of fulcrums, force points, and action points, known by names such as a double ball tap, may be used.

Explanation of Signs

[0035] 1... Diagonal flow pump in water 10... Axial flow pump in water 100... Door body 101... Bracket 102... Bottom surface of waterway 2... Casing 21... Suction port 22... Discharge port 3... Motor 31... Output shaft 311... Axis 32... Impeller 33... Guide vane 34... Oil chamber 4... Flap valve 5... Suction cover 64... Air pipe 65... Discharge port 80, 90... Float type automatic air valve control mechanism 84... Float 85... Rod body 89... Air valve 200... Float wobbling prevention mechanism

Claims

1. A casing having a suction port on one side and a discharge port on the other side, an electric motor fixed within the casing and rotationally driven, a centrifugal impeller disposed in a lateral direction in which the axis of the output shaft of the electric motor is horizontal, or disposed at a predetermined angle inclined from the horizontal and connected to the output shaft to be rotationally driven, a suction cover fixed to the casing and having an opening formed therein for sucking fluid, in a submersible pump comprising: an air pipe disposed upstream of the centrifugal impeller and within the submersible pump for sucking air into the submersible pump from a discharge port, an air on-off valve control mechanism for supplying or shutting off air to the air pipe, wherein the air on-off valve control mechanism comprises an air on-off valve for supplying or shutting off air to the air pipe, a float that moves up and down by buoyancy according to the water level on the suction port side, and a lever mechanism that transmits the up and down movement of the float to the air on-off valve to control the opening and closing of the air on-off valve, wherein the timing of the water level when opening and closing the air on-off valve is different between when the water level rises and when the water level falls, the lever mechanism has one end fixed to the float and the other end provided with the air on-off valve serving as a lid for opening and closing, and has a float anti-vibration mechanism that swings about a swing axis and has positions that selectively lock at two different positions when the water level rises and when the water level falls, wherein the float anti-vibration mechanism comprises a rod body that swings about a swing axis formed by the float fixed to one end and the air on-off valve fixed to the other end, a spring case that swings together with the rod body and is provided with a spring, a first locking portion that is a first recess of a locking portion formed in a fixed cam plate and that locks at the position when the water level rises and comprises a steel ball or a roller that is urged by the spring and fits into the first recess, and a second locking portion that is a second recess of the locking portion formed in the cam plate and that locks at the position when the water level falls and comprises the steel ball or the roller that is urged by the spring and fits into the second recess, and is characterized in that it is a submersible pump with an air pipe.

2. In the submersible pump with an air pipe according to Claim 1, the submersible pump with an air pipe is a submersible mixed-flow pump in which the flow path of the fluid driven by the centrifugal impeller is inclined with respect to the axis, or a submersible axial-flow pump in which the flow path of the fluid is in the axial direction of the axis. and is characterized in that it is a submersible pump with an air pipe.

3. In the submersible pump with an air pipe according to claim 1 or 2, the center axis of the discharge port is arranged parallel to the axis. A submersible pump with an air pipe, characterized by the above.

4. In the submersible pump with an air pipe according to claim 1 or 2, the discharge port is arranged facing the impeller. A submersible pump with an air pipe, characterized by the above.

5. In the submersible pump with an air pipe according to claim 1 or 2, the air pipe is connected to the suction cover or the casing. A submersible pump with an air pipe, characterized by the above.

6. A submersible pump facility using the submersible pump with an air pipe according to any one of claims 1 to 5, wherein the submersible pump with an air pipe is mounted on a sluice gate or a weir gate that crosses a river or a waterway. A submersible pump facility with an air pipe, characterized by the above.

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