JP6637784B2 - Horizontal axis pump suction cover structure - Google Patents

Description

  The present invention relates to a suction cover structure of a horizontal shaft pump installed at a boundary between one waterway and another waterway.

  Conventionally, for the purpose of flood control, for example, at the junction of rivers and waterways, a water stop gate equipped with a drainage pump is installed on a water stop gate door body that can be freely opened and closed, and one of the water gates is partitioned off A pump gate has been constructed to transfer water from the channel to the other channel by a drain pump. In response to a demand for downsizing of a pump gate, a horizontal axis pump installed so that a suction port of the pump is parallel to a water surface of a water channel is used as a drainage pump.

  Since the horizontal axis pump takes in the water flowing in the water channel into the pump as it flows, the flow direction is stable, and the water can be sucked to a lower water level than a pump gate using a vertical axis pump.

  However, when the water level drops near the upper end of the suction part of the horizontal axis pump, an air suction vortex that sucks air from the water surface is generated, leading to a reduction in pump performance such as a decrease in pumping amount and cavitation, noise, vibration, There has been a problem that mechanical inconvenience such as wear of the underwater bearing occurs.

  For this reason, Patent Document 1 discloses that the horizontal axis pump is installed such that the suction port of the horizontal axis pump and the upper wall of the suction cover face obliquely downward with respect to the free water surface of the water flowing through the water channel, so that the trueness of the suction port is reduced. There has been proposed a submersible pump capable of preventing suction from above as much as possible and suppressing the occurrence of air suction vortices, while enabling stable suction to a low water level.

  Patent Document 2 discloses a vortex generation preventing member capable of changing the direction of flow of flowing water flowing from the rear side of a submersible pump, in order to prevent the generation of vortices of flowing water sucked from near a lower portion of a suction port of the submersible pump. A submersible pump provided near the lower part of the suction port has been proposed.

JP-A-2002-21050 JP 2007-31968 A

  In the submersible pumps disclosed in Patent Documents 1 and 2 described above, water can be stably sucked to a low water level, but the operation and stop of the pump may be frequently repeated.

  Even if the water level of the channel separated upstream from the suction cover is higher than the suctionable water level, the suction water flow generated by the pump causes the water level near the suction cover to drop below the suctionable water level. Is stopped immediately, and when the pump stops, the water level near the suction cover instantaneously rises above the suctionable water level, and when the rise in the water level is detected, the pump starts operating immediately.

  Therefore, in order to prevent the operation and stop of the pump from being repeated frequently, it is necessary to continue the operation of the pump regardless of the water level, such that the operation becomes aerial when the water level decreases and the pumping operation is performed when the water level increases. Conceivable.

  However, even in this case, if the pumping operation and the aerial operation are frequently repeated, mechanical inconveniences such as noise, vibration, and wear of the underwater bearing may occur.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a suction pump structure for a horizontal axis pump that can suppress occurrence of frequent start and stop of the pump or occurrence of frequent switching between pumping operation and air operation in view of the above-described problems. On the point.

In order to achieve the above-mentioned object, a first characteristic configuration of the suction cover structure of the horizontal pump according to the present invention is as described in claim 1 of the claims. A suction cover structure of the horizontal shaft pump installed in the section, a switching valve mechanism for switching between aerial operation and pumping operation based on the water level is arranged on the upper or side of the suction cover, and the switching valve mechanism is A first suction opening is formed near the lowest suction water level, and a discharge opening is formed at a position higher than the first suction opening, and water drawn from the first suction opening is discharged from the discharge opening. An inverted U-turn flow path that passes through a higher position and leads to the discharge opening, and a second suction opening that is formed at a position higher than the minimum suction water level and that passes through a position lower than the second suction opening. And the reverse U-turn flow path Comprising a forward U-turn flow path communicated, and the second suction opening is open toward the outside of the suction cover, together with the discharge opening is open toward the inside of the suction cover And the switching valve mechanism constitutes a part of the suction cover .

  When the water level of the water channel is higher than the second suction opening, each U-turn flow path is filled with water drawn from the first and second suction openings, so that the inside of the suction cover is filled with water and stable. Pumping operation is performed. When the water level of the water channel falls below the second suction opening and becomes near the lower part of the forward U-turn flow path, air flows in from the second suction opening and the water seal of the reverse U-turn flow path is released, and as a result, suction is performed. Air flows into the inside of the cover and the operation switches to in-air operation.

  When the water level of the water channel rises from the lowest suction water level and becomes higher than the second suction opening, each U-turn flow path is filled with water drawn from the second suction opening and is water-sealed. Is filled with water, and the operation switches from aerial operation to pumping operation.

Therefore, a hysteresis characteristic of the water level can be obtained when switching between the in-air operation and the pumping operation, frequent switching between the in-air operation and the pumping operation is avoided, and the generation of an air suction vortex near the minimum suction water level is achieved. Can also be avoided. Moreover, since a part of the suction cover is constituted by the switching valve mechanism, a simple structure can be realized, and the cost of parts can be reduced.

The second feature structure, in addition to the first characteristic feature of the above mentioned, the forward U turns passage located outside the suction cover, the inverted U-turn flow path positioned inside the suction cover As described above, the forward U-turn flow path and the reverse U-turn flow path have a multilayer structure overlapping in the thickness direction.

  Since the forward U-turn flow path and the reverse U-turn flow path have a multilayer structure in which they are superposed in the thickness direction, it is sufficient to arrange the respective flow paths so that they are superposed in the thickness direction. Also, the switching valve mechanism can be configured simply and inexpensively.

The third feature structure, in addition to the first or second characteristic feature of the above mentioned, the forward U-turn flow path and the inverted U-turn flow path at different positions from each other in the surface direction of the suction cover Consists of a single-layer structure

  Since the forward U-turn flow path and the reverse U-turn flow path may be arranged at different positions in the surface direction of the suction cover, the switching valve mechanism can be configured to be thin.

The fourth characterizing feature of the from the first upper mentioned in addition to the third one of characteristic configuration of the forward U-turn flow path and the inverted U-turn flow path, the flow path arranged in the suction cover The point is that it is constituted by a forming member.

  For example, if the reverse U-turn flow path and the forward U-turn flow path are configured by a flow path forming member such as a pipe and arranged on the suction cover, the switching valve mechanism can be easily configured.

The fifth characterizing feature of the from the first upper mentioned in addition to the fourth one of characteristic structure of the inverted U-turn flow path and the forward U-turn flow path and there is no bent portion communicating flow path Having a second suction opening on the opposite side of the forward U-turn flow path and a discharge opening on the opposite side of the reverse U-turn flow path.

  With such a configuration, the switching valve mechanism can be configured very easily. For example, a very simple configuration can be achieved by arranging two bent plate-shaped members at an interval.

The sixth characterizing feature of from the first upper mentioned in addition to the fourth one characteristic feature of the no channel-portion and the first suction opening and the inverted U-turn flow path communicates bending In which the forward U-turn flow path is disposed adjacent thereto.

Characteristic feature of the horizontal axis pump according to the present invention, from the first upper predicates in that it has a suction cover structure with a sixth one characterizing feature of the.

Characteristic feature of the horizontal pump gate apparatus according to the present invention is that it comprises a horizontal axis pump with characteristic feature of the above mentioned.

  As described above, according to the present invention, it is possible to provide a suction cover structure of a horizontal shaft pump that can suppress occurrence of frequent start and stop of the pump, or occurrence of frequent switching between pumping operation and air operation. Now you can.

Front view of a pump gate according to the present invention Front view of a pump gate according to the present invention (A) Top view of a pump gate according to the present invention, (b) Main part plan sectional view of a pump gate according to the present invention (A) Illustration of pumping operation of pump gate according to the present invention (b) Illustration of aerial operation of pump gate according to the present invention (c) Illustration of air / water mixing operation of pump gate according to the present invention (A) is a sectional side view of a suction cover structure provided with a switching valve mechanism showing another embodiment, and (b) is a plan view of the switching valve mechanism. (A) is a sectional side view of a suction cover structure provided with a switching valve mechanism showing another embodiment, and (b) is a plan view of the switching valve mechanism. Side sectional view of a suction cover structure provided with a switching valve mechanism showing another embodiment.

  An embodiment of the suction cover structure of the horizontal shaft pump according to the present invention will be described below. As shown in FIG. 1 to FIG. 3A, a pump gate 3 is installed at a boundary between the first water channel 1 (for example, a tributary river) and the second water channel 2 (for example, main river). The pump gate 3 is provided on a concrete floor panel 4 (4a) supporting a sluice column 4 (4b) erected at the boundary, a floor member 4c laid laterally at the bottom of the water channel, and a lifting mechanism 7, and is made of a steel plate. A water stop gate door 6 is supported by an elevating mechanism 7 so as to be freely opened and closed.

  The elevating mechanism 7 rotates a pair of rack rods 7a fixed to the water stop gate door body 6 via a joint 7b and a pinion gear in a gear box 7c disposed above the sluice post 4 (4a) in the forward or reverse direction. It comprises an electric motor 7f to be driven, a manual operation handle 7d, and a drive connection mechanism 7e for driving the other gear box 7c side in conjunction with the other motor box 7c side by an electric motor 7f drivingly connected to one gear box 7c side. ing.

  When the pinion gear is rotated by the electric motor 7f or the manual operation handle 7d, the water stop gate door body 6 supported by the rack bar 7a can move up and down.

  A pair of left and right through-holes is formed in the center of the water stop gate 6 to communicate between the two water channels 1 and 2, and the water stop gate 6 is lowered in each of the through holes when the water stop gate 6 is lowered. A pump device 11 for draining water from one channel 1 to the second channel 2 is provided.

  The pump device 11 includes a horizontal axis pump including a pump casing having an axis P installed in a substantially horizontal posture and an impeller housed in the pump casing.

  A base end of a suction cover 23 is flange-connected to a pump casing at a suction side end facing the first waterway 1 which is a tributary river of the pump device 11, and a switching valve mechanism 22 according to the present invention is incorporated in the suction cover 23. I have.

  A flap valve 12 is openably and closably attached to a discharge-side end facing the second waterway 2 which is a mainstream river, and allows a flow from the first waterway 1 which is a tributary river to the second waterway 2 which is a mainstream river. The configuration is such that the flow of water from the second waterway 2 which is a mainstream river to the first waterway 1 which is a tributary river is prevented.

  A driving device 5 for driving and controlling the pump device 11 installed on the gate floor member 4b of the pump gate 3 is arranged. The driving device 5 and the pump device 11 are connected by a power supply cable PL, and a signal of a water level sensor (not shown) is input to the driving device 5. When power is supplied to the pump device 11 via the power supply cable PL based on the water level of the first water channel 1 detected by the water level sensor, the pump device 11 is started, and when the power supply is stopped, the pump device 11 is stopped.

  That is, when the water level of the first water channel 1 reaches the pump activation water level in a closed state with the water stop gate door body 3 lowered, the pump device 11 is operated, and the water of the first water channel 1 is discharged to the suction side end of the pump device 11. The flap valve 12 is pushed open by the water pressure, and is drained from the discharge side end into the second water channel 2.

  Further, when the pump device 11 is stopped when the water stop gate door 3 is in the closed state, drainage from the first water passage 1 to the second water passage 2 is stopped, and the flap valve 12 has its own weight and the first water passage. It is automatically closed by the combined action with the water pressure of the two water passages 2, and backflow of water from the second water passage 2 to the first water passage 1 is prevented.

  As shown in FIG. 3 (b), the suction cover 23 is formed of a tubular body arranged such that the opening 24 on the distal end side faces the bottom of the first water channel 1. More specifically, the suction cover 23 has an upper plate portion 23A having a distal end arranged in an inclined posture toward the bottom of the first water channel 1, and left and right side plates formed to extend downward from left and right edges of the upper plate portion 23A. And a bottom plate 23C connecting the lower edges of the left and right side plate portions 23B.

  A switching valve mechanism 22 that functions as a switching valve that switches between aerial operation and pumping operation based on the water level of the first water channel 1 is welded or bolted to the upper plate portion 23A of the suction cover 23.

  The switching valve mechanism 22 includes a reverse U-turn flow path 22e located on the suction side of the pump casing, and a forward U-turn flow path 22d located farther from the suction side of the pump casing than the reverse U-turn flow path 22e. ing.

  In the reverse U-turn flow passage 22e, the first suction opening 22a is formed near the lowest suction water level LWL, and is higher than the first suction opening 22a. In the present embodiment, the impeller shaft center of the pump device 1 is used. A discharge opening 22b is formed at a position higher than P, and is a flow path that guides water drawn from the first suction opening 22a to a position higher than the discharge opening 22b to the discharge opening 22b.

  The forward U-turn flow path 22d is formed at a position higher than the lowest suction water level LWL, and in the present embodiment, the second suction opening 22c is formed on the intermediate water level MWL side, and passes through a position lower than the second suction opening 22c. The third opening 22f formed at substantially the same height is a flow path that communicates with the reverse U-turn flow path 22e.

  That is, the second suction opening 22 c is opened toward the outside of the suction cover 23, and the discharge opening 22 b is opened toward the inside of the suction cover 23.

  Further, the forward U-turn flow path 22d and the reverse U-turn flow path 22d are located such that the forward U-turn flow path 22d is located outside the suction cover 23 and the reverse U-turn flow path 22d is located inside the suction cover 23. It has a multilayer structure overlapping in the thickness direction.

  The reverse U-turn flow path 22e guides water drawn from the first suction opening 22a to a discharge opening 22b from a position higher than the discharge opening 22b via the third opening 22f along the flow path. The forward U-turn channel 22d is formed so as to communicate with the reverse U-turn channel 22e at the third opening 22f.

  As shown in FIG. 4A, when the water level sensor detects that the water level in the first water channel 1 has reached the pump start water level HWL, the driving device 5 supplies power to the pump device 11 to start the pump device 11. .

  When the pump device 11 is started, water is sucked into the pump casing from the first suction opening 22a along the reverse U-turn flow path 22e, and at the same time, the pump is drawn from the second suction opening 22c along the forward U-turn flow path 22d. Water is sucked into the casing.

  As a result, the reverse U-turn flow path 22e and the forward U-turn flow path 22d that constitute the switching valve mechanism 22 are in a water-sealed state filled with water, the inside of the suction cover 23 is in a negative pressure state, and the first water path is formed. The pump 1 is in a pumping operation state in which the water 1 is sucked from the opening 24 of the suction cover 23, and the flap valve 12 is opened by the pumping pressure at this time, and drained to the second water channel 2.

  Even if the water level of the first water channel 1 decreases in the pumping operation state, if the water level is higher than the intermediate water level MWL corresponding to the second suction opening 22c, the water sealing state of the switching valve mechanism 22 is maintained. Therefore, the pumping operation state is continuously maintained.

  However, as shown in FIG. 4B, when the water level of the first water channel 1 drops below the intermediate water level MWL and drops to near the lowest point of the forward U-turn flow path 22d, the water sealing state of the switching valve mechanism 22 is reached. Is released, and the air sucked from the second suction opening 22c flows into the suction cover 23 from the discharge opening 22b of the reverse U-turn flow passage 22e via the forward U-turn flow passage 22d. Become. As a result, the inside of the suction cover 23 that has been in the negative pressure state becomes equal to the atmospheric pressure, so that the pumping operation is blocked and the operation is switched to the in-air operation.

  As shown in FIG. 4C, even if the water level of the first water channel 1 subsequently rises, if the water level is lower than the intermediate water level MWL corresponding to the second suction opening 22c, the air is discharged from the discharge opening 22b. Is sucked, so that the pump device 11 is maintained in the air operation state. At this time, the air-water mixing operation may be slightly performed.

  Further, when the water level rises and becomes higher than the intermediate water level MWL corresponding to the second suction opening 22c, water is sucked from the second suction opening 22c, and the switching is performed in the same manner as in FIG. The valve mechanism 22 enters the water seal state. As a result, the inside of the suction cover 23 becomes negative pressure, the suction of water from the opening 24 is restored, and the operation is switched from the aerial operation to the pumping operation.

  Therefore, when the water level of the first water channel 1 is significantly lower than the intermediate water level MWL, the water sealing state of the switching valve mechanism 22 is released and the pumping operation state shifts to the air operation state, the water level becomes the intermediate water level MWL. When the water level in the first water channel 1 rises above the intermediate water level MWL until the switching valve mechanism 22 enters the water-sealed state and shifts to the pumping operation state, the intermediate operation is performed until the water level rises. Since the pumping operation state is maintained until the water level drops significantly below the water level MWL, frequent switching between the in-air operation and the pumping operation is avoided. That is, the pump device 11 performs the hysteresis operation for the water level fluctuation by the switching valve mechanism 22.

  In addition, as shown in FIG. 4B, during the in-air operation, the heat sucked from the discharge opening 22b can suppress the heat generation of the pump device.

  When such operation is repeated and the water level in the first water channel 1 decreases and the state in which the minimum suction water level LWL is detected by the water level sensor continues for a predetermined time, the driving device 5 determines that the drainage is no longer necessary. The power supply to the pump device 11 is stopped.

  Since the switching valve mechanism 22 is configured as a part of the suction cover 23, a simple structure can be realized, and component costs can be reduced. In addition, the second suction opening 22c of the switching valve mechanism 22 is provided with the opening in a horizontal straight line, so that even if there are foreign substances on the water surface, the entire opening is not completely clogged by them, and the air and the air can be reliably removed. Suction of water can be performed.

  Further, the switching valve mechanism 22 has a simple manufacturing process, and easily creates a plurality of flow paths by cutting and bending a sheet metal using, for example, SUS304 or the like, and welding processing in which the processed sheet metals are layered and welded. And can be constructed inexpensively.

  In the above-described embodiment, the example in which the switching valve mechanism 22 is provided above the suction cover 23 has been described. However, the switching valve mechanism 22 can be provided not on the suction cover upper part 23A but on the suction cover side part 23B. The above-described effects unique to the present invention are effective even when the switching valve mechanism 22 is provided not only on the suction cover upper portion 23A but also on the suction cover side portion 23B or on both the upper and side portions.

  As shown in FIG. 5, the reverse U-turn flow path 22e and the forward U-turn flow path 22d may have a single-layer structure arranged at different positions in the surface direction of the suction cover 23. With this configuration, the forward U-turn flow path 22e and the reverse U-turn flow path 22d may be arranged at different positions in the surface direction of the suction cover, so that the switching valve mechanism 22 can be configured to be thin. become.

  As shown in FIG. 6, the reverse U-turn flow path 22e and the forward U-turn flow path 22d may be configured by a flow path forming member such as a pipe disposed in the suction cover. For example, if the reverse U-turn flow path and the forward U-turn flow path are configured by a flow path forming member such as a pipe and arranged on the suction cover, the switching valve mechanism 22 can be easily configured.

  As shown in FIG. 7, a portion 22f in which the reverse U-turn flow path 22e and the forward U-turn flow path 22d communicate with each other is formed by an unbent flow path. It may be configured to have the suction opening 22c and to have the discharge opening 22b on the opposite side of the reverse U-turn flow path 22e. With this configuration, it can be manufactured very easily. For example, it can be configured by arranging three plate-like bodies at intervals.

  Further, a portion where the first suction opening communicates with the reverse U-turn flow path may be configured by a flow path without bending, and a forward U-turn flow path may be arranged adjacent thereto.

  In the above-described embodiment, an example is described in which the pump gate is constructed at the boundary which is the junction of the tributary river as one of the waterways and the main river as the other waterway, but the construction position of the pump gate according to the present invention is The type of the channel is not limited as long as it is constructed at the boundary between one channel and the other channel. Needless to say, one waterway and the other waterway may correspond to the upstream and downstream sides or the upstream and downstream sides of the same waterway.

  The material of the switching valve mechanism 22 is not limited to a sheet metal using, for example, SUS304, but may be any known material such as a hard resin or carbon reinforced fiber.

  In the above-described embodiment, the suction cover structure of the horizontal axis pump installed on the pump gate has been described.However, the suction cover structure of the horizontal axis pump according to the present invention is not limited to that installed on the pump gate, It can be applied to horizontal shaft pumps widely used for flood control in civil engineering works and civil engineering facilities.

  The embodiment described above is an aspect of the present invention, and the present invention is not limited to the description, and the specific configuration of each unit can be appropriately changed and designed within a range in which the operation and effect of the present invention is exerted. Needless to say.

1: First waterway 2: Second waterway 3: Pump gate 4: Gate 4a: Gate 4b: Floor member 4c: Concrete floor panel 5: Drive unit 6: Water stop gate door 7: Elevating mechanism 7a: Rack rod 7b: joint 7c: gear box 7d: manual operation handle 7e: drive connection mechanism 11: pump device 12: flap valve 22: switching valve mechanism 22a: first suction opening 22b: discharge opening 22c: second suction opening 22d. : Forward U-turn flow path 22e: Reverse U-turn flow path 22f: Third opening 23: Suction cover 23A: Upper part of suction cover (upper plate part)
23B: suction cover side (side plate)
23C: Suction cover bottom (bottom plate)
24: Opening HWL: Pump starting water level MWL: Intermediate water level LWL: Minimum suction water level PL: Power supply cable

Claims (8)

A suction cover structure of a horizontal axis pump installed at a boundary between one waterway and the other waterway,
A switching valve mechanism that switches between aerial operation and pumping operation based on the water level is arranged on an upper portion or a side portion of the suction cover,
The switching valve mechanism,
A first suction opening is formed near the lowest suction water level, and a discharge opening is formed at a position higher than the first suction opening, and water drawn from the first suction opening is discharged from the discharge opening through the discharge opening. An inverted U-turn channel that passes through a high position and leads to the discharge opening;
A second suction opening formed at a position higher than the lowest suction water level, and a forward U-turn flow path passing through a position lower than the second suction opening and communicating with the reverse U-turn flow path;
Wherein the second suction opening is opened toward the outside of the suction cover, the discharge opening is opened toward the inside of the suction cover, and the switching valve mechanism is used to open the suction cover. Is a suction cover structure of a horizontal axis pump, a part of which is configured . The forward U-turn channel and the reverse U-turn channel are arranged in the thickness direction such that the forward U-turn channel is located outside the suction cover and the reverse U-turn channel is located inside the suction cover. 2. The suction cover structure for a horizontal shaft pump according to claim 1 , wherein the suction cover structure has a multi-layer structure superimposed on the suction shaft.   The horizontal shaft pump according to claim 1, wherein the reverse U-turn flow path and the forward U-turn flow path have a single-layer structure arranged at different positions in a plane direction of the suction cover. Suction cover structure. The inverted U-turn flow path and the forward U-turn passage, the suction cover structure of the horizontal axis pump according claims 1-3 which is composed of a flow passage forming member disposed on the suction cover. A portion where the reverse U-turn flow path and the forward U-turn flow path communicate with each other is formed by a flow path without bending, and has a second suction opening on the opposite side of the forward U-turn flow path, suction cover structure of the horizontal axis pump of claims 1 4 further comprising the discharge opening on the opposite side of the U-turn flow path. Wherein the first suction opening and the inverted U-turn flow path portions communicating constituted by free channel-bending, the horizontal axis of claims 1 to 4, wherein adjacent thereto to place the order U-turn flow path Pump suction cover structure. The horizontal axis pump having a suction cover structure of claims 1-6. A horizontal pump gate device comprising the horizontal shaft pump according to claim 7 .

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