JPH08284868A - Horizontal shaft pump - Google Patents

Abstract

PURPOSE: To shorten a span of time till pumping operation is started as well as to make it conformable even to a sudden rise in a water level. CONSTITUTION: A suction chamber 8B of an ejector 8 is connected to a pump casing 5 via a suction pipe 9, while an air tank 10B of a compressed air supply source 10 is connected to an inlet 8C of the ejector 8 via a second feed pipe 12, and compressed air is fed to the ejector 8 from the air tank 10B, whereby the inner part of a pump is made into promotion of negative pressure in a short time by means of ejector action, and thereby a water level in the pump is made to be raised up to a self-primable water level (for example, a full water level HHWL) of the impeller 3.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a horizontal shaft pump.

[0002]

2. Description of the Related Art Conventionally, a horizontal axis pump installed in a pump suction well 1 of a drainage pump station shown in FIG. 3 has a structure that when the water level of the suction well 1 rises to a pumping start water level HWL, this water level HW
L is detected by a water level detecting means (not shown), and the intake valve 7 installed in the intake pipe 7 based on the detection signal.
The valve A is opened and the vacuum pump 21 is started.
As a result, the inside of the pump casing 5 and the inside of the suction pipe 4 are made to have a high negative pressure, and the water in the suction pipe 4 reaches the impeller 3 in the pump casing 5 and is drained by the self-priming ability of the horizontal shaft pump. Is raised to a full water level HHWL
Here, the pump is started by operating the full water detector 22, and the discharge valve 6 on the downstream side of the impeller 3 is fully opened to perform the drainage operation (pumping operation).

That is, the conventional horizontal axis pump is constructed so that the pumping operation is performed by raising the water level in the pump to the full water level HHWL by the vacuum pump 21. Therefore, the water level of intake well 1 is the pumping start water level HWL.
It takes a long time to raise the water level in the pump to the full water level HHWL and start the pumping operation. For this reason, when the water level of the water intake well 1 rises rapidly, there is a risk that the response may be delayed.

[0004]

The problem to be solved is that it takes a long time to raise the water level in the pump to a level that allows the impeller to self-prime and start the pumping operation. If the water level of No. 1 suddenly rises, there is a risk that the response may be delayed.

[0005]

DISCLOSURE OF THE INVENTION According to the present invention, an ejector for reducing the internal pressure of a pump to a water level capable of self-priming the impeller, and an ejector connected to an inlet of the ejector to provide compressed air to the ejector. It is characterized by having a compressed air supply source for supplying water, and it has achieved the purpose of shortening the time until the start of pumping operation and being able to cope with a sudden rise in water level.

[0006]

According to the present invention, by supplying compressed air from the compressed air supply source to the inlet of the ejector, the negative pressure in the pump can be reduced in a short time by the action of the ejector, and the water level in the pump can be sucked by the impeller. It is possible to raise the water level to a certain level (eg full water level).

[0007]

An embodiment of the present invention will be described below with reference to the drawings. The same or corresponding parts as those of the conventional example described in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.
In FIG. 1, the ejector 8 is connected to the pump casing 5. Specifically, the suction chamber 8B, into which the throttle portion 8A is inserted and which is open, is connected to the pump casing 5 via the intake valve 9A and the intake pipe 9. In addition, the pump casing 5 has a full water detector 22 in parallel with the intake pipe 9.
Is connected. The compressed air supply source 10 is connected to the inlet 8C of the ejector 8. The compressed air supply source 10 includes an air compressor 10A and an air tank 10B that stores compressed air supplied from the air compressor 10A. The air compressor 10A and the air tank 10B are provided with a first check valve 11A. Trachea 11
The air tank 10B and the inlet 8C of the ejector 8 are connected to each other by the second air supply pipe 12 provided with the air supply valve 12A.

In the above structure, when the water level of the water intake well 1 rises to the pumping start water level HWL, this water level HWL is detected by the water level detecting means (not shown), and based on this detection signal, it is passed to the second air supply pipe 12. Air supply valve 12 installed
A and the intake valve 9A provided in the intake pipe 9 are opened. As a result, the compressed air in the air tank 10B enters the ejector 8 from the inlet 8C through the second air supply pipe 12, and is discharged into the atmosphere from the outlet 8D. The compressed air that has entered the ejector 8 from the inlet 8C passes through the narrowed portion 8A, so that the pressure in the suction chamber 8B decreases and the inside of the pump (the pump casing 5, the suction pipe 4, the discharge pipe) passes through the intake pipe 9. Is sucked, the pressure in the pump is made negative in a short time, the water level in the pump is raised to the full water level HHWL, and the pumping operation is started.

As described above, by supplying the compressed air from the compressed air supply source 10 to the inlet 8A of the ejector 8, the inside of the pump is negatively pressured in a short time by the ejector action, and the water level in the pump is raised to the full water level HHWL. Therefore, as compared with the conventional horizontal axis pump configured to perform the pumping operation by raising the water level in the pump to the full water level HHWL by the vacuum pump 21 shown in FIG. The time can be greatly reduced. Therefore, even if the water level of the suction well 1 rises rapidly, it is possible to cope with the water level rise without delay. In addition, when using it as a preceding standby operation pump,
As shown in FIG. 2, it may be attached to the upper part of the suction pipe 4.

[0010]

As described above, according to the present invention, by supplying compressed air from the compressed air supply source to the inlet of the ejector, the pressure inside the pump is reduced to a negative pressure in a short time by the ejector action and the water level in the pump is increased. Since the water level of the impeller can be raised to a self-priming water level (for example, full water level), the time required to start the pumping operation can be significantly shortened as compared with the conventional horizontal axis pump. As a result, it is possible to respond to the rapid rise in the water level of the intake well without delay.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view when performing a preceding standby operation.

FIG. 3 is a sectional view of a conventional example.

[Explanation of symbols]

 3 Impeller 4 Suction pipe 5 Pump casing 8 Ejector 10 Compressed air supply source HHWL Full water level (water level at which the impeller can self-prime)

Claims (1)

[Claims] 1. An ejector for reducing the negative pressure in the pump to raise the water level in the pump to a water level at which the impeller can self-prime.
A horizontal shaft pump comprising a compressed air supply source connected to an inlet of the ejector to supply compressed air to the ejector.