JPH0249974A - Intake water path for pump - Google Patents

Abstract

PURPOSE:To prevent the generation of a turbulent flow following partial operation of a pump by forming two or more circulating parts, connecting each water path between partitions to communicate, in the two or more partitions, provided to be arranged in the inside of a water introducing path, and setting the total of sectional area of each circulating part not less than the sectional area of each water path. CONSTITUTION:Three sets of pumps 2a to 2c and two or more partitions 3a, 3b, partitioning these pumps, are provided to be arranged in the inside of an intake water tank 1. While is intake water tank 1 connects to its upstream side successively a spread flow path part 4, curving flow path part 5 and an introducing water flow path part 6, providing each partition 3a' to 3''', 3b' to 3''', mutually continued, to be arranged in the inside of the flow path part. Here each partition 3a''', 3b''' of the introducing water flow path part 6 forms many circulating parts 7 (7a to 7a'', 7b to 7b'') connecting each water path of communicate. And each opening width L1 to L3 of each circulating part 7 is set for width W of each water path so as to satisfy a relation where L1+L2+L3>=W.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an intake channel that is provided upstream of a pump water intake tank and has a conduit for supplying water to the water intake tank.

[Conventional technology]

A pump intake channel is usually composed of a headrace, an enlarged channel section connected to the downstream side of the headrace channel, and a water intake tank connected to the downstream side thereof.

Depending on the topographical conditions of the pumping station, a bent portion may be provided between the water conduit and the expanded flow path section, or the expanded flow path portion may be bent.

If multiple main pumps are installed in the above water intake tank,
A partition wall is provided to partition the main pumps (specifically, between the suction ports of the main pumps) to prevent harmful vortices from occurring near the pump suction ports. With the present invention.

The term "pump" also refers to the main pump.

In order to supply evenly rectified water to each of the areas partitioned by the above-mentioned partition walls in the water intake tank, the main pumps are installed in both the expanded flow path and the headrace channel. A bulkhead is installed to divide the waterway into the same number of waterways.

Regarding this type of technology, for example, one experiment (25
Page 1 (C)) is known.

Although the above-mentioned known document discusses the suction pit of two chamber shaft pumps, this known technique is also applicable to pumps other than the shaft pump, and also to three or more pumps.

FIG. 4 is an explanatory diagram schematically depicting a conventional example of an intake channel.

There are three pumps in the water intake tank 1, namely pump A 2a and pump B.
A pump 2b and a C pump 2c are provided.

In the water intake tank 1, there is a partition wall 3a that partitions the pumps.

3b is provided.

An enlarged channel section 4, a bent section 5, and a water conduit 6 are provided on the upstream side of the water intake tank 1.

Enlarged section partitions 3 a' and 3 b' are provided in the enlarged channel section 4 to face the partition walls 3 a and 3 b.

Inside the bent portion 5, the enlarged portion partition walls 3a' and 3b are provided.
Bent part partition walls 3a' and 3b' are provided connected to the bent part partition walls 3a' and 3b', and the bent part partition walls 3a' and 3b' are connected to the above-mentioned bend part partition walls 3a' and 3b'.
'.

Water conduit partition walls 3a'' and 3b'' are provided in communication with 3b'.

In this way, in the conventional technology, water channels for the number of pumps are formed from the headrace channel that is the most upstream side of the pump intake channel to prevent swirling or uneven flow in the flowing water, and to create a uniform flow for multiple pumps. It is devised to provide rectification.

[Problem to be solved by the invention]

In the conventional example shown in FIG. 4, three pumps 2a, 2
When pumps b and 2c are operating evenly, there will be no problem with separate installations, but when one part of multiple pumps is operated, there is a problem that uneven flow or swirling flow may occur. For example, if one of the three pumps
This often occurs when the machine is a spare machine.

FIG. 5 is an explanatory diagram of the above problem.

To simplify the explanation, regarding the two pumps A and B,
A case where two units are operated and a case where one unit is operated are illustrated.

FIG. 5(a) schematically depicts the state in which 82 pumps A are in operation.
It is divided into two waterways 6A and 6B.

A. The 82 pumps are operating equally.

Flowing water is supplied in an even and smooth rectified flow as shown by the additional arrows.

FIG. 5(b) shows a case where pump B is stopped and pump A is operated at its rated value.

In this case, since it cannot flow into the waterway 6B, the water that has flowed as shown by the arrow A changes direction as shown by the arrow C and enters the waterway 6B.
Concentrate on A.

Therefore, a separation area 12 is generated on the water channel 6A side at the upstream end of the partition wall 11, and a swirling flow (arrows 2 to 7) is generated downstream of the separation area 12.

In this way, the disturbance of the streamlines adversely affects the flow in the pump water intake tank and induces a vortex flow at the pump suction port.

A similar problem also occurs when one pump B is operated, as shown in FIG. 5 <c>.

In order to solve this problem, an attempt was made to provide one opening 12 in the partition wall 11 as shown in FIG. 5(C), but this did not produce a sufficient effect.

The present invention has been made in view of the above-mentioned circumstances, and is designed to provide an intake channel that does not cause separation flow, drift flow, or swirling flow in the headrace channel even when a plurality of main pumps are partially operated. The purpose is to

[Means to solve the problem]

The intake channel of the present invention created in order to solve the above problems includes: (i) a water channel bulkhead that divides the interior of the water channel connected to the upstream side of the pump water intake tank in which a plurality of main pumps are installed into a plurality of water channels; (ii) The above-mentioned headrace partition wall is configured to be cut out intermittently in the longitudinal direction (ie, the direction of the flow path). The cutout portion forms a flow section that connects the water channels separated on both sides of the water conduit partition.

(iii) A plurality of the above-mentioned flow sections shall be provided per one headrace partition wall, and the total cross-sectional area of the flow section shall be greater than or equal to the cross-sectional area of the divided waterway.

Specifically, the total cross-sectional area of the plurality of flow portions provided in one headrace partition is greater than or equal to the cross-sectional area of each divided waterway.

When a bent part or an expanded channel is connected to the downstream side of the headrace, the flow part located on the most downstream side among the plurality of flow parts provided in the headrace partition wall is connected to the headrace. It is desirable to keep it 1.5 parts or more away from the downstream end of the waterway bulkhead. However, W is the width dimension of the waterway divided by the waterway partition wall.

Furthermore, when a screen is provided along with the water conduit, it is desirable to provide the screen upstream of the most downstream flow section among the plurality of flow sections.

[Effect]

FIG. 6 is an explanatory diagram of the operation of means for solving the problems shown in the upper column.

FIG. 6(a) schematically depicts a state in which a conventional headrace partition wall 11 is provided to divide the inside of the headrace 6', the B pump is in operation, and the A pump is stopped.

In such a conventional example, the water flowing as shown by arrows A and A' cannot flow into the water channel 6A, so the water flows as shown by arrows A and A'.
Concentrates on waterway 6B.

Therefore, near the most upstream portion b1 of the water channel 6B, the flow channel cross-sectional area is narrowed down to 172, and the flow velocity suddenly becomes about twice as large. For this reason, the separation flow and swirling flow described above occur.

As shown in FIG. 6(b), the isolation 13 has a distribution section 13a, 13
If b is provided, the water flowing as shown by arrow A will flow into the water channel 6B as shown by arrow C, but the water that has flowed as shown by arrow A' will be diverted as shown by arrows N and R, and a part of it will be diverted as shown by arrows N and R. Into waterway 6B, the rest is waterway 6A
flow inside.

For this reason, although the flow velocity increases slightly near the most upstream portion bl of the waterway 6B, a sudden doubling of the flow velocity does not occur.

The water that has flowed into the waterway 6B as shown by the arrows wo, wa,
Proceed like a force.

A portion of the water that has flowed into the waterway 6A as shown by the arrow is flowing into the flow section 1.
3a and merges with the water flow in the water channel 6B as indicated by the arrow y.

Therefore, the water flow in the water channel 6B rises slightly near the point b2 corresponding to the flow section 13a.

The remainder of the water flow in the water channel 6A passes through the flow section 13b and joins the water flow in the water channel 6B as indicated by the arrow.

In this way, the flow velocity in the water channel 6B is changed to the point bI+ shown in the figure.
At bZ+ b3, the speed increases in three stages, and finally the arrow forces and arrows merge completely, resulting in approximately twice the flow speed.

The total cross-sectional area of the flow passages of the above-mentioned flow sections 13a and 13b is:
It is equal to or larger than the channel cross section of the water channel 6A (or 6B).

For this reason, the speed of the water flows that merge through the flow section as shown by arrows y and y becomes smaller than the flow speed in the water channel 6B (the flow speed of the water flow on the side receiving the merging), resulting in vortices and separation flows caused by the merging. The occurrence of is suppressed.

The effect that the flow velocity in the water conduit increases in stages and does not locally cause excessive flow velocity is achieved by the unique design of the present invention, which is achieved by specially devising the number, arrangement, and cross-sectional area of the flow sections. This is because it depends on the configuration.

〔Example〕

FIG. 1 shows an embodiment of the pump intake channel according to the present invention,
FIG. 2 is a schematic plan view.

This embodiment is an improvement by applying the present invention to the conventional example shown in FIG. 4, and the same drawing reference numbers as in FIG. It is a constituent part.

Next, points different from the conventional example (FIG. 4) will be explained.

The headrace waterway bulkhead 3a'' provided in the headrace waterway 6 and the same 3
For each of ``b'', there are three flow parts 7a, 7a', 7a' and 7b, 7b in the long plane direction (direction along the water flow, left-right direction in the figure) to interrupt the water conduit partition. ', 7b' are provided.

Thereby, the water channels divided by the headrace partition wall are communicated with each other at a plurality of locations.

The water conduit in this example is configured to have a uniform depth.

W is the width dimension of each divided waterway.

Distribution section 7a, 7a', 7a' and 7b, 7b
The opening width dimension in the plan view of ', 7b' is Ll +
It is LZt L3.

And the dimension of Ll r L2+ L3 above is Ll+
Set so that L2+L3≧W.

In this example, for example, when the B pump 2b is stopped and the A pump 2a and the C pump 2C are operated at their rated operation, the flow velocity (arrow) V+l is compared to the flow velocity (arrow) 2. Same v3
is increased to approximately 3/2. (It is not exactly 3/2. There is an effect of the narrowing of the channel width due to the thickness of the headrace partition wall and the exchange between channels at the downstream end of the expanded channel 4.) However, since multiple flow sections were provided, Flow velocity (arrow)
V+ is increased in speed in four stages before and after each flow section without rapidly increasing the flow velocity (arrow) to V3 at one point.

Since the speed is increased in stages in this way, the rectification in the headrace is not disturbed, and no eddies, swirling flows, or separated flows occur.6 Moreover, the total width of the channel in the flow section Ig + L2 + L
Since 3 is larger than W, there is no possibility that a portion of excessive flow velocity will occur in the flow section and induce a vortex flow.

The illustrated section L4 is between the junction of the water conduit 6 and the bent portion 5 and the most downstream flow portions 7a' and 7b'. The length 4 of this section is set to 1.5W or more (W is the waterway width). By providing the linear portion with L4=1.5W in this way, the water flow that merges in the flow portions 7 a' and 7 b' is almost completely rectified before flowing into the bent portion 5.
The water flow distribution within the bent portion 5 is not adversely affected.

Although not shown in the drawings, when directly connecting the headrace channel to the enlarged flow channel, similarly, 1.5
It is desirable to provide a straight portion of W or more.

FIG. 2 shows a different embodiment from the above. The difference from the previous embodiment is that a screen 9 (or screen 10) is provided.

It is desirable that a screen for preventing foreign matter (for example, driftwood) from flowing in is provided on the upstream side of the water conduit partition wall 38''3b'' as shown in FIG. Although it may be provided in the middle of the headrace partition wall as shown in 10, at least the most downstream flow section 7a
', installed on the upstream side of the 7-bit.

When foreign matter gets stuck on the screen, there is a risk that the foreign matter will cause drifting or swirling flow, but if there is a flow section downstream, the turbulence of the water flow caused by the foreign matter on the screen will be alleviated in the flow section. This is because that.

FIG. 3 shows a different embodiment from the above. In this embodiment, a water conduit 6. Bent portion 5. The expanded flow path 4 is connected to six main pumps 2a'
This is an example installed on the upstream side of ~2f'.

As shown in this example, the intake channel of the present invention is constructed by (N/2)-1 water channel partitions so as to divide the water channel into N/2 channels for every two of the N pumps. It can also be applied to intake channels with

〔Effect of the invention〕

As explained above, the pump intake channel of the present invention is applied to an intake channel that has a water channel partition that divides the interior of the water channel connected upstream of a water intake tank in which a plurality of main pumps are installed into a plurality of flow channels. Since a plurality of flow sections are provided in the water conduit partition, when one of the plurality of main pumps is operated, the flow rate increases stepwise in each of the plurality of flow sections, and does not increase rapidly at one point. Since the flow speed is not increased, the generation of drifting flow, separated flow, swirling flow, and vortex flow is prevented.

Furthermore, since the total cross-sectional area of the flow section is set larger than the cross-sectional area of each individual waterway, the flow velocity within the flow section is suppressed, and there is no possibility that excessive flow velocity may locally occur and disturb the overall flow. None.

As a result, when the intake channel of the pump according to the present invention is applied,
Even if a plurality of main pumps are partially operated (partly stopped), there is no risk of harmful eddy currents being generated at the pump suction ports.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing an embodiment of the intake channel of a pump according to the present invention. FIGS. 2 and 3 are schematic plan views showing embodiments different from those described above. FIG. 4 is a schematic plan view of a conventional intake channel. FIG. 5 is an explanatory diagram of an aliIM in a conventional intake channel. FIG. 6 is an explanatory diagram of the operation and effect of the present invention. 1.1'... Water intake tank, 3a, 3b... Partition wall provided in the water intake tank, 3a', 3b'... Enlarged channel partition wall, 3a'. 3b'...bent part partition, 3a'', 3b''...conductor partition. 4... Enlarged channel portion, 5... Bent portion, 6... Water conduit, 7a. 7a', 7a', 7b, 7b', 7b''=Distribution Department, 9.10...Screen.Representative Patent Attorney Tadashi Akimoto Jitsusa S Figure 12 (Width) Fig.

Claims (1)

[Scope of Claims] 1. In an intake waterway in which a waterway partition wall that divides the waterway into a plurality of waterways is provided in the waterway connected to the upstream side of a pump water intake tank in which a plurality of pumps are installed, (a ) A plurality of flow parts are provided in the shape of the headrace partition wall intermittently cut out in the longitudinal direction thereof to allow the water channels divided by the headrace partition wall to communicate with each other; (b) a series of headrace partition walls; A pump intake channel characterized in that the total cross-sectional area of the plurality of flow sections provided in the pump is greater than or equal to the cross-sectional area of each divided water channel. 2. (a) The headrace and the headrace partition are linear in plan view, and (b) the headrace is directly connected to at least one of the bent portion and the enlarged flow path. (c) at least one of the bent portion and the enlarged channel portion is also divided into a plurality of water channels by a partition wall; (e) the flow section provided on the headrace partition is at least 1.5 W away from the connection section;
The intake channel of the pump according to claim 1. However, W is the width dimension of each water channel divided by the headrace partition wall. 3. Claim 1, wherein the water conduit is provided with a screen, and at least one of the plurality of flow sections is provided downstream of the screen. Pump intake channel described in .