JP2002021050A - Gate pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gate pump installed to permit the operation at a low water level aid also to prevent eddy and vortex. SOLUTION: In a water channel, an impeller 27 for discharging water sucked from the inflow side and a motor unit 21 for turning and driving the impeller 27 are built in, and a gate pump 2 equipped with a guide casing 6 having a suction hole 32 at the inflow side is installed, which is arranged at the same core with the drive axis line of the motor unit 21 at the outer periphery of the motor unit 21 forming a ring-shaped gap with the motor unit 21, and the turning and drive shaft line of the gate pump 2 has an angle with the horizontal line and installed at a lower portion in the water channel. As a result, the eddy and vortex are avoided and the operation at the low water level is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a gate pump. More specifically, the present invention relates to a gate pump which is a submersible pump fixedly disposed on a door of a floodgate provided across a river or the like.

[0002]

2. Description of the Related Art A submersible pump placed directly on the door of a floodgate,
That is, various gate pumps (registered trademark of the present applicant) have been proposed. This gate pump generally includes a suction bell mouth, an impeller, a rear guide blade, a discharge casing, a discharge flap valve, and the like. The following three types are known as mounting types of the pump on the gate body. A vertical axis type in which the pump is arranged on the upstream side surface of the door body, a gate built-in type in which the pump is arranged inside the gate, and a horizontal axis type in which the rotation axis of the pump is horizontally arranged.

[0003] In all types, the gate pumps are generally arranged in the direction of the axis of rotation vertically, ie vertically, or horizontally, ie horizontally. Since these formats are not the gist of the present invention, detailed description will be omitted. Gate pump
If the shape of the water channel is inappropriate, or if the water level drops and the required submergence depth cannot be ensured, an air suction vortex, a water vortex, and a swirling flow are generated.

[0004] That is, a vortex vortex that can dent the water surface, an air vortex that grows and reaches the suction port, especially an underwater vortex generated in the riverbed, a concentric vortex generated when the water level drops to the pump suction port, In addition, swirling flow is generated due to drift, vortex, rotation of the impeller, and the like in the water channel, and disturbs uniform inflow to the impeller.

[0005] The minimum operable water level of a vertical pump or a vertical suction pipe is generally the height from the riverbed of the bell mouth (the bottom clearance C).
1) and the distance (submerged depth S1) from the bellmouth to the free water surface required to avoid the air suction vortex. Here, when C1 is reduced, the flow velocity passing around the suction port increases in inverse proportion to the decrease in the passage area, and the occurrence of a submerged vortex or swirling flow is likely to occur.

Further, when S1 is reduced, the distance from the bell mouth to the vortex generated on the free water surface is shortened, so that the air suction vortex is easily generated. These air suction vortices, submerged vortices, and swirling flow cause mechanical problems such as reduced pump performance such as reduced pumping amount, cavitation, and reduced head, noise, vibration, underwater bearing wear, and blade erosion.

Therefore, in order to avoid these problems, the pump diameter d is generally set to C to prevent continuous vortex suction.
It is determined that 1 ≧ d and S1 ≧ 1.5 to 2d. If the C and S dimensions are small, it is possible to operate to a low water level without digging.

In particular, when it is necessary to lower the minimum operable water level, a vertical shaft pump excavates a riverbed. on the other hand,
Regarding the horizontal axis pump, air suction vortices are likely to be generated on the upstream side of the pump. To avoid this, recommended values for the pump mounting height C2 and the required submergence depth S2 are determined similarly to the vertical axis pump.

[0009]

Particularly, in the case of the horizontal axis gate pump, since the flow direction of the water channel and the suction and discharge directions coincide with each other, the loss is small, and the flow is uniform and hard to be disturbed. The air suction vortex is less likely to be generated, and the channel width can be made smaller than that of a vertical shaft pump having the same diameter. However, a simple horizontal-axis pump (horizontal trumpet pipe) that is installed horizontally has a limit in the installation depth when air suction vortex is generated upstream of the pump when the suction depth of the suction port is reduced.

When the suction port is installed close to the riverbed or the side wall, the water flows downward from the water surface toward the suction port to generate a swirling flow between the suction port, the side wall, and the riverbed, and the swirling flow turns the vortex into the air suction vortex. Enhances growth and adversely affects pump performance. In order to avoid hollow vortices, etc., an appropriate depth was absolutely necessary from the water surface. Therefore, in the case of the horizontal axis pump, if the flow in the water channel is the same, the bottom surface interval and the depth of submersion tend to be longer than that of the vertical axis pump.

The present invention has been made under the above-mentioned technical background, and achieves the following objects. SUMMARY OF THE INVENTION It is an object of the present invention to provide a gate pump which is mounted and installed so as to reduce the influence of a vortex, an air suction vortex, a swirling flow and the like. Another object of the present invention is to provide a gate pump capable of operating in a low water level waterway.

[0012]

A gate pump according to the present invention includes a guide casing having a built-in impeller and a motor unit, an annular gap formed between the impeller and the motor unit, and having a suction port on an inflow side. And the gate pump is provided so that the rotary drive axis is installed below the waterway at an angle to the horizontal line. Further, the gate pump of the present invention is characterized in that a mounting portion to the gate is provided on the guide casing.

Further, the gate pump of the present invention is characterized in that the suction port is made wider than the inner hole of the guide casing. Further, the gate pump of the present invention is characterized in that a horizontal side edge of the suction port is made longer in an axial direction of the gate pump than a riverbed side edge.
Further, the gate pump according to the present invention is characterized in that a cover is provided at the edge of the horizontal surface on the suction port side so as to protrude in the inflow direction.

Further, the gate pump of the present invention is characterized in that the suction port is rectangular. Further, the gate pump of the present invention is characterized in that the guide casing is attached to the door so that the impeller is located on the downstream side of the door. Further, the gate pump according to the present invention is characterized in that the motor unit portion of the guide casing is exposed to the inflow side from the suction port.

[0015]

[First Embodiment] A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional side view showing a gate pump according to the present invention. FIG. 1 shows an example in which the rotation axis 50 of the impeller 27 is fixed and installed at a position at an inclination angle α from the horizontal. This installation method according to the present invention has a small energy loss because the discharge of the gate pump 2 is directed upward, but has a great advantage that the water can be pumped up to a position where the water depth is shallower than the horizontal axis pump. The details will be described below.

The door 1 is a weir constituting a gate. In the present embodiment, a gate pump 2 is arranged and fixed to a door 1 constituting a roller gate which is a kind of the gate. Both ends of the back surface of the door 1 are supported up and down in a door groove (not shown) and receive water pressure. To receive the water pressure, a roller (not shown) is fixedly disposed on a portion of the rear surface of the door body 1 which is in contact with the door groove. These structures and functions are well-known technologies, and description thereof will be omitted.

A pump fixing plate 3 is fixed to the inflow side, which is one of the side surfaces of the door 1, with bolts 4. This fixing may be performed by welding. The pump fixing plate 3 is for fixing the gate pump 2 related to the present invention to the door 1 in a detachable manner, and is a rectangular fixing plate having a predetermined thickness.

In the first embodiment, the pump fixing plate 3
Is shaped so that the pump is inclined. That is, the door 1
In contrast, the water surface side 3a of the pump fixing plate 3 is made longer than the riverbed side 3b to give the pump fixing plate 3 an acute inclination angle α. Therefore, the gate pump 2 inclines the suction port 32 downward.

The gate pump 2 is connected to the pump fixing plate 3
There is also a method of directly attaching a guide casing 6 to be described later to the inclination angle without using the
However, when the inclination angle needs to be changed, it becomes inflexible. Attachment via the pump fixing plate 3 is effective in such a case, and it is possible to cope with a change in the inclination angle by changing only the pump fixing plate 3 without changing the gate pump 2.

An opening 5 is formed in the center of the pump fixing plate 3. The opening 5 is a through hole for passing the pumped up water. A guide casing 6 is fixedly arranged on the water inflow side (normally, on the upstream side) of the opening 5. The guide casing 6 is an outer main body constituting the gate pump 2. The guide casing 6 includes an annular portion 7 and a tapered portion 8 which is integral with and continuous with the annular portion 7.

A fixed flange 9 is integrally formed in front of the guide casing 6, and a rear portion has a suction port 32 which is an annular space communicating with the tapered portion 8 with an annular gap. The suction port 32 is for sucking water from the inflow side. The pump fixing plate 3 is formed by a plurality of bolts 10.
By fixing the fixing flange 9 to the gate pump 2
Is fixed to the door 1.

In the present embodiment, six guide blades 15 are arranged at equal angular positions on the inner peripheral surface of the tapered inner hole 12 of the tapered portion 8. The guide blade 15 is twisted with respect to the central axis so that the inflowing water can be rotated. The water flowing from the annular inner hole 11 is given a swirling motion according to the twist. A motor unit mounting portion 20 having a cylindrical outer shape is arranged at the center position and integrally connected to the guide blade 15.

Therefore, the guide vanes 15 have a function of imparting swirling motion to water and fixing the motor unit 21. The outer shape of the motor unit mounting portion 20 is substantially the same as that of the tapered inner hole 12, and the inside thereof is hollow. The motor unit mounting portion 20 and the motor unit 21 are connected to each other by bolts 22.
Is fixed to the rear end. The guide blade 15 gives a swirling flow to the water flowing into the suction port 32 in a direction opposite to an impeller 27 described later.

The motor unit 21 is a motor having a built-in squirrel-cage induction motor and generating a rotational driving force by electric power. An impeller hub 25 is key-fixed to the output shaft of the motor unit 21. In this example, four (or two or three) rotating blades 26 are arranged on the outer periphery of the impeller hub 25 at equal angular intervals on the outer periphery in this example. The impeller hub 25 and the rotating blades 26 constitute an impeller 27. The motor unit 21 drives the impeller 27 to rotate.

In front of the impeller hub 25, an impeller boss 28 having a curved surface with a rounded front and a flat end surface is fixed to an output shaft of the motor unit 21 with a nut (not shown). I have. On the other hand, one end of the cover 30 is fixed to the upper part of the rear end face of the guide casing 6 by bolts 31. The cover 30 is a rectangular plate so as to avoid inhaling air when the water level drops. That is, when the gate pump 2 is operating, the water level near the suction port 32 of the guide casing 6 decreases.

The lowering of the water level causes the air to be sucked in, causing harmful vibrations and lowering the pumping efficiency. This is to cover the vicinity of the water surface and prevent the air from flowing into the suction port 32. There is also a function for removing dust floating on the water surface so as not to be sucked. By providing the cover 30, the point of occurrence of the vortex is separated to the upstream side of the pump suction port 32.

The flow from the free surface around the dimple vortex to the suction port 32 becomes a flow nearly parallel to the riverbed in a state in which the flow wraps around the cover 30, so that the dimple vortex hardly occurs. Further, taking into account the fact that the cross-sectional area of the passage through the suction port 32 is increased, the downward flow to the suction port 32 is alleviated, and the vortex is less likely to grow into the air suction vortex.

[Second Embodiment] FIG. 2 shows a second embodiment in which the guide casing 6 is formed obliquely. In the second embodiment, the portion incorporating the motor unit 21 (not shown) is inclined, and the downstream portion of the door body 1 attached is horizontal. The structure of the gate pump according to the second embodiment is different from that of the first embodiment, and the suction side and the discharge side are covered by a casing having the same diameter. For example, this type is known in Japanese Patent Application Laid-Open No. 11-166496, Japanese Patent Application No. 299164, and the description of the structure is omitted.

In the case of the second embodiment, since the flow in the downstream portion is horizontal, the loss is reduced in that the flow does not flow upward due to the resistance to gravity, as compared with the case where the flow flows obliquely upward. Further, with this configuration, the suction port 32a can be positioned below the door body 1. Therefore, even when operation at a particularly low water level is required, the riverbed near the suction port 32a may be dug similarly to the case of the vertical shaft pump, and operation at a low water level is possible.

Third Embodiment FIG. 3 is a conceptual diagram showing an example in which a suction port 32b of an inclined gate pump 2 is widened like a trumpet according to a third embodiment. FIG. 4 is a diagram showing the suction port 32b in FIG. 3 in which the horizontal dimension is longer than the vertical dimension (the direction between the water surface and the riverbed) and the water surface side edge is longer. That is, the dimension between the horizontals 43 and 44 is set to be longer than the dimension between the upper part 41 on the water surface side and the lower part 42 on the riverbed side of the trumpet-shaped inlet 40.

The passage cross section of the suction port 40 is larger than the passage cross section of the annular inner hole 11. Furthermore, since the suction port 40 is installed obliquely downward, a wide passage area is provided even when the water level is lowered, and since the suction port 40 is close to the riverbed, the flow velocity distribution is uniform, and a configuration in which a hollow vortex or the like is hardly generated. Becomes

Even if a vortex is generated, the position of the vortex is located upstream of the suction port 40, and
Since it is located at a position apart from 0, it is hardly affected by the dent vortex. Also, the downward flow velocity near the vortex is small, and the vortex does not easily grow into an air suction vortex. Therefore, operation at a low water level becomes possible.

FIG. 5 shows another embodiment showing the shape of the suction port 40, in which the water surface side edge of the suction port 40 is formed in an arc shape. The effect is the same as in FIG. FIG. 6 shows an example in which a cover 45 is attached to the upper part of the suction port 32c which is widened like a trumpet. The effect in this case is the same as that of the cover 30.

[Embodiment 4] The flow passing through the pump turns to the downstream side of the pump and turns, and depending on the shape of the water channel and the angle of inclination of the pump, even in the case of the oblique shaft pump, the flow is directed to the suction port like a vertical shaft pump and the vortex is formed. May occur. The configuration of the present invention weakens that. FIGS. 7, 8 and 9 show a fourth embodiment in which the impeller 27 of the gate pump is provided downstream of the door 1. 7 is a side view, FIG. 8 is a front view thereof, and FIG. 9 is a plan view thereof. The fourth embodiment is characterized in that the impeller 27 is arranged on the downstream side, so that the gate pump 2 can be installed closer to the door body 1, so that it is difficult to generate a vortex.

By shortening the length of the guide casing 6, FIG.
However, as shown, the motor unit 21 projects to the inflow side of the guide casing 6 and is exposed. As a result, the suction port 32d is made closer to the door 1 side, so that it is difficult to generate a vortex as in the case described above. A cover 46 is provided above the suction port 32d of the guide casing 6 so that the suction port 32d of the gate pump 2 faces downward. The cover 46 may be installed so that the angle of the cover 46 can be adjusted so that the inclination angle of the cover 46 is at an optimum position.

Vortex suction tends to occur on the downstream side of the vertical pump and on the upstream side of the horizontal pump. Therefore, when the vortex is generated on the downstream side of the diagonal axis, the inclination angle α is reduced, and when the vortex is generated on the upstream side, the inclination angle α is increased. It is. The adjustment of the inclination angle may be performed by a cover.

The passage cross-sectional area of the suction port 32d is made larger than that of the annular inner hole 11 in the guide casing 6 in the same manner as described above, and further, the horizontal width is larger than the vertical width (the width in the direction between the water surface and the riverbed). Is longer. Since the distance from the door 1 mounting surface to the pump suction port 32d is reduced, the stagnation area downstream of the pump is narrowed, the downward flow from the free surface to the pump suction port 32d is weakened, and the vortex is turned into an air suction vortex. It becomes difficult to grow. In addition, since the suction port 32d is directed downward, it is hardly affected by the dent vortex or the air suction vortex. Therefore, operation at a low water level becomes possible.

[Fifth Embodiment] FIG. 10 shows an example applied to a gate pump of a type different from that of FIG. Figure 1
Will be described with reference to FIG. The entire gate pump 2 is installed so as to protrude toward the inflow side.

The guide casing 6 receiving the motor unit 21 is divided into three parts, the guide blade 15 is provided on the downstream side 6a, and the suction port 32 is provided on the inlet side 6b.
To cover the rotating blades 26 of the motor unit 21. Further, the door body side 6c constitutes a mounting portion to the door body 1 and has a motor unit 21 built therein.

In the case of the fifth embodiment, the guide casing 6 serves as a mounting portion for the door body 1. The door body side 6c is further divided so that a fixing plate corresponding to the pump fixing plate 3 in FIG. May be provided. The annular inner hole 11 on the inflow side 6b of the guide casing forms a curve toward the water surface and reaches the suction port 32, which is widened. The suction port 32 forms a trumpet-shaped deformed body. The edge on the water surface side is wider than the riverbed side.

This is similar to the other embodiments described above,
It is for taking in the water current of the horizontal flow smoothly. The motor unit 21 is mounted in a direction opposite to that of FIG. That is, in the case of FIG.
The rotary blade 26 that rotates with respect to 5 is disposed on the inflow side.

The motor unit 21 is installed at an angle of α degrees with respect to the horizontal axis. This motor unit 2
The impeller boss 28 attached to the tip of one has a streamline shape that is deformed to assist a smooth water flow.
The guide casing 6 is fixed to the door 1 via the pump fixing plate 3. The water sucked in from the inflow side changes its direction in the lateral direction from around the motor unit 21, passes through the inside of the pump fixing plate 3, and is guided in the downstream direction.

[Other Embodiments] The suction opening 32 formed between the guide casing 6 and the motor unit 21 is an annular gap having a circular cross section. However, the cross-sectional shape of the suction port 32 may have a cross section such as a horizontal or vertical polygon, a flat circular shape, or an elliptical shape. It is not limited to the embodiment.

[0044]

The gate pump 2, which is a small submersible pump according to the present invention, is attached to the door body 1 at an angle with respect to the horizontal axis to prevent a dent vortex, an air suction vortex, a swirling flow, etc., and a suction port close to the riverbed. Can be installed, allowing operation at a lower water level than conventional horizontal shaft pumps.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration and an attached state of a gate pump.

FIG. 2 is a conceptual diagram showing an installation state of a gate pump in which a portion incorporating a motor unit is inclined and a downstream portion of the gate is horizontally installed.

FIG. 3 is a conceptual diagram showing that a suction port of an inclined gate pump is widened like a trumpet.

FIG. 4 is a partial view showing a rectangular suction port of FIG. 3;

FIG. 5 is a partial view in which only the upper part of the suction port of FIG. 4 is shortened.

FIG. 6 is a conceptual diagram showing that a cover is provided above the suction port of FIG. 3;

FIG. 7 is a conceptual diagram of a gate pump showing an example in which an impeller is provided on the downstream side of a gate and a riverbed side is cut away in a guide casing.

FIG. 8 is a front view of FIG. 7;

FIG. 9 is a plan view of FIG. 7;

FIG. 10 is a sectional view showing another embodiment different from FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Door body 2 ... Gate pump (submersible pump for gate pumps) 3 ... Pump fixing plate 6 ... Guide casing 7 ... Annular part 9 ... Fixing flange 15 ... Guide blade 21 ... Motor unit 26 ... Blade 27 ... Impeller 30 ... Cover 32: suction port 40: suction port α: inclination angle

Continuation of the front page (72) Inventor Takahiro Maeda 15-1 Ise-cho, Saga-shi, Saga Mizota Co., Ltd. F term (reference) 2D019 AA41

Claims (8)

[Claims] An impeller for discharging water sucked from an inflow side and a motor unit for driving the impeller to rotate are provided in a water channel, and an outer periphery of the motor unit is provided. A gate pump having a guide casing disposed concentrically with a drive axis of the motor unit, forming an annular gap with the motor unit, and having a suction port on an inflow side, wherein the gate pump is connected to the drive axis. The gate pump is configured to be installed at a lower angle in a waterway at an acute angle with a horizontal line. 2. The gate pump according to claim 1, wherein a portion for attaching the gate pump to the gate is provided on the guide casing. 3. The gate pump according to claim 1, wherein a cross-sectional area of flowing water at a suction port of the guide casing is larger than a cross-sectional area of an inner hole of the guide casing. 4. The gate pump according to claim 1, wherein a water surface side edge of the suction port of the guide casing is longer than a riverbed side edge in an axial direction of the gate pump. Gate pump to do. 5. The gate pump according to claim 1, wherein a cover is provided at a water-side edge of the suction port so as to protrude in an inflow direction. 6. The gate pump according to claim 1, wherein an edge of the suction port is rectangular. 7. The gate pump according to claim 1, wherein the guide casing is attached to the door so that the impeller is positioned downstream of the door. 8. The gate pump according to claim 1, wherein the motor unit portion of the guide casing is exposed to an inflow side from the suction port.