JPH05231396A - Pump - Google Patents

Abstract

PURPOSE:To perform siphon breaking associated with a water level by connecting an upper end side of a siphon breaking pipe, whose lower end opening is positioned in the lowest water level of a suction water level, to the top part of a siphon pipe, in a pump wherein the halfway of a delivery pipe is constituted into the siphon pipe. CONSTITUTION:When an impeller 7 is rotated through a rotary shaft 6 by a driving gear, water in a water suction path 2 is sucked up, to induce residual air in a top part 5a of a siphon pipe 5 which constitutes a delivery pipe. In this way, the inside of the siphon pipe 5 is vacuumized to form a siphon and to automatically perform suction/deliver. Next, a delivery process of water in the water suction path 2 is advanced, and when the water in the suction water path 2, that is, a pump suction water level is lowered down to the lowest water level LWL, a lower end opening 9b of a siphon breaking pipe 9 appears above the water surface. Then by generating a pressure in the top part 5a of the siphon pipe 5 at the atmospheric pressure or less, air is sucked from the lower end opening 9b of the siphon breaking pipe 9 to generate siphon breaking, and action of suction and delivery is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump configured to discharge a large amount of water with a low head having a small difference in height between suction and discharge.

[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 set at a level position higher than the maximum water level (HWL) on the discharge side. In some cases, it is configured as a siphon tube, that is, a so-called siphon type installation. This is because, for example, in the case of a vertical shaft type, the residual air in the top part of the siphon tube is attracted by suction by the impeller at the time of start-up to form a siphon in a vacuum state to automatically perform suction and discharge, and the suction water level is When stopping at the minimum water level, a valve as a vacuum breaker attached to the top of the siphon tube is opened to cause siphon breakage and drop water.

[0003]

However, according to the conventional structure as described above, in order to break the siphon when the pump is stopped, it is necessary to attach a valve as a vacuum breaking device to the top of the siphon tube, and the suction suction is performed. Since it is necessary to open the valve when the water level reaches the minimum water level, there is a problem that not only the equipment cost is high, but also failure is likely to occur unless the valve maintenance is strictly managed.

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 surely cause siphon destruction when the pump is stopped and can be manufactured at low cost. To do.

[0005]

In order to achieve the above object, the present invention is directed to a pump in which a siphon tube is constructed by setting the middle of the discharge pipe at a position higher than the highest water level on the discharge side, and The upper end side of the siphon breakage pipe located at the lowest water level of the suction water level is connected to the top of the siphon pipe.

[0006]

With the above structure, when the pump suction water level drops to the minimum water level, the lower end opening of the siphon breakage pipe appears on the water surface, and air is sucked from the lower end opening to cause siphon breakage and stop the pump. . Therefore, there is no need to provide a special vacuum breaking valve, which reduces costs and eliminates the risk of valve failure.
The reliability of the operation is increased in combination with the fact that the siphon destruction is linked to the water level.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below 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 casing, one end side of which is connected with a suction pipe 3 located in a water suction passage 2 and the other end thereof. A discharge pipe 5 extending to the drainage channel 4 is connected to the side. Reference numeral 6 denotes a rotary shaft which is provided so as to vertically penetrate the casing 1 and is driven by an external rotary drive device (not shown), and an impeller 7 and the like are attached to the lower end side thereof. The discharge pipe 5 is arranged at a level higher than the highest water level (HWL) with the apex 5a in the middle thereof as a siphon pipe.

Reference numeral 9 is a siphon breaking pipe whose upper end 9a side is connected to the top 5a of the siphon pipe 5, and a lower end opening 9b thereof is located at the lowest water level (LWL) of the suction water level. An emergency valve 10 is attached to the top portion 5a of the siphon pipe 5 so that the siphon can be arbitrarily destroyed regardless of the water level when necessary.

Next, the operation of the above configuration will be described. If the rotary shaft 6 is driven by the rotary drive device,
The impeller 7 rotates to suck up the water in the water suction passage 2 and draw out the residual air in the top portion 5a of the siphon pipe 5 forming the discharge pipe 3. As a result, the siphon tube 5
The inside is evacuated to form a siphon, and suction and discharge are performed automatically.

When the water in the introduction water channel 2, that is, the pump suction water level is lowered to the lowest water level (LWL), the lower end opening 9b of the siphon breaking pipe 9 appears on the water surface. At this time, since the top portion 5a of the siphon pipe 5 is below atmospheric pressure, air is sucked from the lower end opening 9b of the siphon breaking pipe 9 to cause siphon breakage, and suction / discharge operations are stopped. In this way, the siphon can be broken without providing a valve as a vacuum breaking device, so that it can be manufactured at a low cost. Moreover, there are fewer failures than the valve, and when the suction water level drops to the minimum water level (LWL), the siphon can be reliably destroyed in response to it, so it is more reliable than the valve. Becomes
Further, by operating as the water level responsive type, an automatic flow rate adjusting function is provided.

The siphon breakage depends on the diameter of the siphon breakage pipe 9. The diameter may be determined according to the flow velocity of water in the siphon pipe 5.

[0012]

As described above, according to the present invention, by connecting the upper end side of the siphon breaking pipe whose lower end opening is located at the lowest water level of the suction water to the top of the siphon pipe which constitutes the discharge pipe, Even without using a valve as a vacuum breaker, it is possible to reliably cause siphon breakage in conjunction with the water level. Therefore, there is an effect that it is possible to provide a pump having excellent reliability in vacuum breaking operation while being manufactured at low cost.

[Brief description of drawings]

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

[Explanation of symbols]

 5 Discharge pipe (siphon pipe) 5a Top part 9 Siphon break pipe 9a Upper end 9b Lower end opening LWL Minimum water level

Claims (1)

[Claims] 1. A pump in which a siphon pipe is constructed by setting the middle of the discharge pipe at a higher level position than the highest water level on the discharge side, and the upper end side of the siphon breaking pipe whose lower end opening is located at the lowest water level of the suction water level. Is connected to the top of the siphon tube.