JPH05231397A - Pump - Google Patents

Abstract

PURPOSE:To shorten a siphon forming time and further to reduce a cost and improve reliability by promptly removing residual air in the top part of a siphon pipe of constituting a delivery pipe even without using a vacuum pump or the like at the time of starting. CONSTITUTION:An air suction pipe 11 having a negative pressure generating opening 10 directed in a flow direction of water is set up in a flow path outlet part 5b of a siphon pipe 5, to connect this air suction pipe 11 to inside a top part 5a of the siphon pipe 5 through a communication pipe 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large capacity pump used when a large amount of waste water is discharged with a low head.

[0002]

2. Description of the Related Art As is well known, in a pump having a low head with a small water level difference between suction and discharge, the middle of the discharge pipe is located at a level higher than the maximum water level (HWL) and the discharge pipe is siphoned. Often installed in a shape. In this siphon-type installed pump, it is necessary to eliminate air in the siphon-type discharge pipe at the time of starting to form a siphon. In this case, conventionally, the flow velocity in the siphon pipe is constant (at least 1).
It is said to be more than m / s) so that the residual air in the top of the siphon flows out, or
A means for forming an intake hole at the top of the siphon and forcibly discharging residual air using a vacuum pump or the like has been adopted.

[0003]

However, of the above-mentioned conventional siphon forming means, the former one has a structure in which residual air is introduced only by increasing the flow velocity above a certain level, so that it is considerably long for siphon formation. It takes time, and the start of normal operation is delayed, especially for large-capacity pumps, it may be delayed for more than ten minutes. In the latter case, a vacuum pump or the like is required, which leads to an increase in equipment cost and an increase in the number of pump station components, resulting in a decrease in reliability of the entire system.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a pump which can shorten the siphon formation time and is simple in terms of equipment and cost. .

[0005]

In order to solve the above problems, the pump of the present invention has an air suction pipe having an opening for generating negative pressure in the flow of water at the flow path outlet of the siphon type discharge pipe. The air suction pipe is installed and communicated with the inside of the top of the siphon type discharge pipe through a communication pipe.

Further, in the pump of the present invention, the inner bottom end portion of the flow path outlet portion of the siphon type discharge pipe is formed in a convex portion upward,
An air suction pipe having an opening directed in a direction orthogonal to the flow direction is installed so as to utilize the negative pressure generated on the downstream side of the convex portion, and the air suction pipe and the top of the siphon-shaped discharge pipe are connected to each other. The configuration is such that they are communicated with each other through a communication pipe.

[0007]

With the above structure, when the water sucked by the start of the pump is discharged through the siphon type discharge pipe, a negative pressure is generated on the opening side of the air suction pipe at the flow path outlet of the siphon type discharge pipe. Therefore, the residual air in the top part of the siphon is drawn into the air suction pipe side through the communication pipe and is discharged together with the water flow, thus promoting the formation of the siphon.

[0008] Further, an air suction is provided in which the inner bottom end of the flow path outlet of the siphon type discharge pipe is formed in a convex upward, and an opening is formed so as to utilize the negative pressure generated on the downstream side of the convex. Even when a pipe is installed, a negative pressure is generated in front of the opening by the water flow at the time of starting, the residual air in the top of the siphon is discharged through the communication pipe, and the formation of the siphon is promoted.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a pump according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a pump casing, and one end of the pump casing has a suction pipe 3 located in a water suction passage 2.
And a discharge pipe 5 extending to the drainage channel 4 is connected to the other end. Reference numeral 6 designates an external rotary drive device (not shown) provided vertically through the pump casing 1.
Is a rotating shaft driven by an impeller 7 at its lower end.
Is attached. Reference numerals 8 and 8 ′ are bearings for supporting the rotary shaft 6, and 9 is a fixed guide vane located above the impeller 7 and fixed to the pump casing 1. The discharge pipe 5 is formed as a siphon pipe by arranging the middle portion thereof as a top portion 5a at a level higher than the highest water level (HWL).

At the flow path outlet portion 5b of the siphon tube 5,
An air suction pipe 11 having a substantially C-shaped cross section having a plurality of negative pressure generating openings 10 oriented in the water flow direction is arranged in a horizontal position so as to cross the outlet portion 5b as shown in FIG. The air suction pipe 11 and the top 5 of the siphon pipe 5
The inside of a is communicated with each other through a communication pipe 12. Reference numeral 13 is an electromagnetic valve or a check valve which is interposed in the communication pipe 12 and which prevents a backflow after the siphon is formed. Reference numeral 14 denotes a vacuum breaking valve attached to the top portion 5a of the siphon tube 5 for opening the valve when the pump is stopped to break the siphon.

Next, the operation of the above configuration will be described. When the rotary shaft 6 is driven by the rotary drive device, the impeller 7 rotates and the water in the water suction passage 2 is sucked up and is discharged to the drainage passage 4 from the flow passage outlet portion 5b over the top portion 5a of the siphon pipe 5. It Since the air suction pipe 11 opening in the flow direction of water is arranged at the flow path outlet portion 5b, a negative pressure P is generated on the downstream side of the air suction pipe 11 by the flow of water. Therefore, the residual air A in the top portion 5a of the siphon pipe 5 is drawn into the air suction pipe 11 side through the communication pipe 12, becomes bubbles and is discharged together with the water flow. Therefore, the siphon formation of the siphon tube 5 is performed in a short time, and the transition to the normal operation is promptly performed. In addition, the siphon tube 5 is used to promote the siphon formation.
Since it can be achieved by a simple structure in which the air suction pipe 11 having the opening 10 is provided in the flow path outlet portion 5b of the above, it can be manufactured at a lower cost than that in which residual air is forcibly discharged using a vacuum pump or the like. Becomes

In the above embodiment, the air suction pipe 11 is installed in a horizontal posture so as to traverse the siphon pipe 5, but as shown in FIGS. 3 and 4, the air suction pipe 1 is shown.
Even if 1 is installed in a vertical position, the same effect can be obtained.

FIG. 5 shows a modified example of the essential part of the present invention, in which the inner bottom end portion 5c of the flow path outlet portion 5b of the siphon tube 5 is formed in a convex shape upward, and the flow direction of the inner bottom end portion 5c. An air suction pipe 51 having a C-shaped cross section having an opening 50 for generating a negative pressure that is upward and orthogonal to the flow direction is provided in the front. In this case as well, a negative pressure P is generated above the opening 50 by the flow of the water, and siphon formation can be promoted similarly to the above.

[0014]

As described above, according to the present invention, an air suction pipe having an opening for generating a negative pressure facing the flow direction of water is installed at the flow path outlet of the siphon type discharge pipe, Since the suction pipe and the inside of the siphon are connected to each other, the residual air in the top of the siphon is drawn out to the air suction pipe side by the negative pressure generated before the opening due to the flow of water at the time of start, thereby forming the siphon. It can be performed in a short time, and the structure is simple and the cost can be reduced as compared with the case where a vacuum pump or the like is provided.

Further, according to the present invention, the inner bottom end of the flow path outlet of the siphon type discharge pipe is turned upside down, and an opening for generating a negative pressure is provided in front of the inner bottom end of the siphon type discharge pipe. Since an air suction pipe was provided and this air suction pipe was connected to the top of the siphon, residual air was drawn above the air suction pipe using effective negative pressure to promote siphon formation and the siphon formation time. Can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a pump according to an embodiment of the present invention.

FIG. 2 is a plan cross-sectional view of an arrangement portion of an air suction pipe in the pump.

FIG. 3 is a schematic configuration diagram of a pump when the air suction pipe is arranged in a vertical posture.

4 is a cross-sectional view taken along the line IV-IV of FIG.

FIG. 5 is a schematic sectional view showing a modified example of the main part of the present invention.

[Explanation of symbols]

 5 Discharge pipe (siphon pipe) 5a Top part 5b Flow path outlet part 10 (50) Opening 11 (51) Air suction pipe 12 Communication pipe HWL Maximum water level P Negative pressure

Claims (2)

[Claims] 1. A pump in which the middle portion of the discharge pipe is located at a level higher than the maximum water level and the discharge pipe is arranged in a siphon shape, wherein in the flow path outlet of the siphon type discharge pipe, the A pump characterized in that an air suction pipe having an opening for generating a negative pressure is installed, and the air suction pipe and the inside of the top of the siphon type discharge pipe are communicated with each other via a communication pipe. 2. A pump in which the middle of the discharge pipe is located at a level higher than the highest water level and the discharge pipe is arranged in a siphon shape, wherein the inner bottom end of the flow path outlet of the siphon type discharge pipe faces upward. An air suction pipe having an opening directed in the direction orthogonal to the flow direction is installed so as to utilize the negative pressure generated on the downstream side of the projection, and this air suction pipe and the siphon type A pump characterized in that it communicates with the inside of the discharge pipe via a communication pipe.