JPH08284866A - Horizontal shaft pump - Google Patents

Abstract

PURPOSE: To eliminate generation of large vibrations and noises in this horizontal shaft pump while avoiding any no-discharge operation by loading one side or the other side of negative pressure and atmospheric pressure at the suction side of this pump, on a driving means, and making a blade regulating member shift to the expanding direction of a blade clearance or to the formation position of a normal blade clearance. CONSTITUTION: Till a discharge valve 6 is opened, a blade clearance selector control means 11 makes a driving means 10 load one side of negative pressure and atmospheric pressure at the suction side of this horizontal shaft pump, shifting a blade clearance adjusting member 9 in the expanding direction of a blade clearance. At a point of time when the discharge valve 6 is opened, the blade clearance selector means 11 makes the driving means 10 load the other side of the negative pressure and the atmospheric pressure at the suction side of this pump, shifting the blade clearance regulating member 9 to the formation position of a normal blade clearance. Since it is selected from air operation to pumping operation, supposing that a water level in the pump is raised up to a full water level HHWL by a vacuum system 2, any no-discharge operation at an interval till the discharge valve 6 is opened from this point of time is avoidable.

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 the pressure switch 20 of the vacuum system 2 or a water level detection means (not shown), and the vacuum pump 21 of the vacuum system 2 is started based on this detection signal. As a result, the inside of the suction pipe 4 arranged on the upstream side of the impeller 3 has a high negative pressure, and the water in the suction pipe 4 is pumped into the pump casing 5.
It reaches the impeller 3 inside and is raised to a full water level HHWL where it can be drained by the self-priming ability of the horizontal axis pump, where the discharge valve 6 provided in the discharge pipe 8 on the downstream side of the impeller 3 is fully opened. Then, perform drainage operation (pumping operation).

Further, when the water level of the suction well 1 drops to the operation stop water level LWL due to continuous pumping operation, this water level LWL
Is detected by the pressure switch 20 of the vacuum system 2 or a water level detecting means (not shown), and based on this detection signal, the intake valve 7A provided in the intake pipe 7 is opened to release air into the intake pipe 4. Suction, break the vacuum, stop pumping, switch to air operation, and perform pre-standby operation. In this case, the discharge valve 6 is closed.

In the conventional horizontal axis pump in which the pumping operation or the preceding standby operation is performed by such a method, the water level in the water intake well 1 rises to the pumping start water level HWL, and the vacuum pump 21 is activated, whereby the water level in the pump is increased. When the water level is raised to the full water level HHWL, the water is sent to the discharge valve 6 side by the impeller 3 from this point until the discharge valve 6 is opened, and the horizontal axis pump vibrates greatly. Makes noise.

[0005]

The problem to be solved is to switch from air operation to pumping operation. Therefore, when the pump internal water level is raised to the full water level by the vacuum system, the discharge valve is opened from this point. Until that time, the system will be in a deadline operation state and large vibration and noise will occur in the horizontal axis pump.

[0006]

The present invention comprises a vacuum system connected to a suction pipe upstream of an impeller to generate a negative pressure in the suction pipe, and a discharge valve provided in a discharge pipe downstream of the impeller. In the provided horizontal shaft pump, a blade gap adjusting member movably provided at an inlet of a pump casing accommodating the impeller, a driving unit connected to the blade gap adjusting member, and a connecting unit to the driving unit. One of the negative pressure and the atmospheric pressure on the suction side of the horizontal shaft pump is loaded to move the blade gap adjusting member in the direction of expansion of the blade gap, and the driving means has a large negative pressure on the suction side of the horizontal pump. Load the other side of atmospheric pressure,
And a blade gap switching control means for moving the blade gap adjusting member to a normal blade gap forming position, and in order to switch from the air operation to the pumping operation, the vacuum system is used to change the pump water level to the full water level. Even if it is pulled up to, the shut-off operation from this point until the discharge valve is opened is avoided, and the purpose of preventing large vibration and noise from occurring in the horizontal shaft pump was achieved.

[0007]

According to the present invention, the water level of the suction well in which the horizontal axis pump is installed rises to the pumping start water level, this water level is detected, and the inside of the suction pipe is made highly negative by the vacuum system, Until the water level inside is raised to a full water level where it can be drained by the self-priming ability of the impeller, and the discharge valve on the downstream side of the impeller is opened, the drive control is performed by the switching control of the blade clearance switching control means. One of the negative pressure and the atmospheric pressure on the suction side of the horizontal axis pump is loaded on the blade, and the blade gap adjusting member is moved in the blade gap expanding direction to expand the blade gap. As a result, water does not flow to the discharge valve side, and the shutoff operation is avoided. On the other hand, when the discharge valve is opened, the drive clearance is loaded with the negative pressure and the atmospheric pressure on the suction side of the horizontal shaft pump by the switching control of the blade clearance switching control means, and the blade clearance adjusting member is operated normally. By moving to the position where the gap is formed, the self-priming ability of the impeller is restored and the drainage operation (pumping operation) is performed.

[0008]

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. 3 are designated by the same reference numerals, and detailed description thereof will be omitted.
In FIG. 1, a blade gap adjusting member 9 is movably provided at an inlet of a pump casing 5 in which the impeller 3 is housed, and a driving means 10 is connected to the blade gap adjusting member 9. The blade gap switching control means 11 is connected to the drive means 10.

The blade gap adjusting member 9 has an axis C of the main shaft 12.
From the normal blade gap formation position shown above to the enlarged blade gap position shown below the axis C of the main shaft 12 so that the pump casing 5 can move forward and backward along the axis C of the main shaft 12. It is built into the entrance. The drive means 10 is composed of a plurality of cylinder devices, each of which is a cylinder 10A, and a piston 10B and a cylinder 10A which are incorporated in the cylinder 10A so as to be movable back and forth.
The piston rod 10C is provided so as to project from the blade and is connected to the blade gap adjusting member 9. Blade gap switching control means 11
Is for switching control of the blade gap to either the normal blade gap formation position shown above the axis C of the main shaft 12 or the enlarged blade gap position shown below the axis C of the main shaft 12. One of the ports on the secondary side is connected to the rear chamber of the cylinder 10A via the passage 11A, and the other port on the secondary side is connected to the front of the cylinder 10A via the passage 11B. Connected to the room,
One port on the primary side is connected to the suction side negative pressure portion of the horizontal shaft pump via the passage 11C, and the other port on the primary side is open to the atmosphere.

In the above structure, when the water level of the intake well 1 rises to the pumping start water level HWL, this water level is detected by, for example, a water level gauge (not shown), and the intake pipe 7 is installed based on this detection signal. The intake valve 7A is closed and the vacuum pump 21 of the vacuum system 2 is started. Thereby, the suction pipe 4 arranged on the upstream side of the impeller 3
Is highly negatively pressured, the water in the suction pipe 4 reaches the impeller 3 in the pump casing 5, and is pulled up to a full water level HHWL at which the horizontal axis pump can drain water. Then, until the discharge valve 6 on the downstream side of the impeller 3 is opened, the blade gap switching control means 11 is moved to the axis C of the main shaft 12.
The switching control is performed in the state illustrated below. As a result, a negative pressure on the suction side of the horizontal shaft pump is applied to the rear chamber of the cylinder 10A in the driving means 10, atmospheric pressure is applied to the front chamber of the cylinder 10A, and the blade gap is generated by the differential pressure between the front chamber and the rear chamber. The adjusting member 9 is moved in the expanding direction of the blade gap (leftward in the drawing) to expand the blade gap. As a result, the flow of water shown by the arrow occurs, and the water stops flowing to the discharge valve 6 side,
Deadline operation can be avoided. Therefore, large vibration and noise do not occur in the horizontal shaft pump as in the conventional case.

On the other hand, when the discharge valve 6 is opened, the blade gap switching control means 11 is controlled to switch to the state shown above the axis C of the main shaft 12. Thereby, the driving means 1
At 0, the atmospheric pressure is applied to the rear chamber of the cylinder 10A, the negative pressure on the suction side of the horizontal axis pump is applied to the front chamber of the cylinder 10A, and the blade gap adjusting member 9 is normally operated by the differential pressure between the front chamber and the rear chamber. The blade gap is moved to the position where the blade gap is formed, and the blade gap is set to an appropriate value. As a result, the self-priming ability of the impeller 3 is recovered and the drainage operation (pumping operation) is performed.

When the water level of the suction well 1 is lowered to the operation stop water level LWL by continuing the pumping operation, this water level is detected by the water level gauge, and the intake valve 7A installed in the intake pipe 7 based on this detection signal. The valve is opened to suck air into the suction pipe 7 to break the vacuum, stop the pumping and switch to the air operation, and perform the preceding standby operation. Then, the discharge valve 6 may be closed, and the blade gap adjusting member 9 may be moved in the expanding direction of the blade gap by the above-mentioned operation.

As described above, even if the pump internal water level is raised to the full water level HHWL by the vacuum pump 21 and the discharge valve 6 is closed, a large vibration or noise is generated in the horizontal axis pump while avoiding the shutoff operation. Can be prevented. Moreover,
It is configured such that the driving means 10 is operated and the blade gap adjusting member 9 is moved forward and backward by utilizing the differential pressure between the negative pressure on the suction side of the horizontal axis pump and the atmospheric pressure without using a special pressure source. Therefore, the structure is simple, and the initial cost and running cost can be kept low.

In the above embodiment, the negative pressure on the suction side of the horizontal shaft pump is applied to the rear chamber of the cylinder 10A in the drive means 10, and the atmospheric pressure is applied to the front chamber of the cylinder 10A to adjust the blade clearance. The member 9 is moved in the expanding direction of the blade gap, the atmospheric pressure is applied to the rear chamber of the cylinder 10A, and the negative pressure on the suction side of the horizontal axis pump is applied to the front chamber of the cylinder 10A.
Although it has been described that the blade gap adjusting member 9 is moved to the normal blade gap forming position, as shown in FIG. 2, the driving means 10 is connected to the blade gap adjusting member 9 from the opposite side, and the driving means 10 is connected. The negative pressure on the suction side of the horizontal shaft pump is applied to the front chamber of the cylinder 10A, and the atmospheric pressure is applied to the rear chamber of the cylinder 10A to move the blade gap adjusting member 9 in the expanding direction of the blade gap. Atmospheric pressure is applied to the front chamber of the cylinder 10A, and negative pressure on the suction side of the horizontal axis pump is applied to the rear chamber of the cylinder 10A to move the blade gap adjustment member 9 to the normal blade gap formation position. Good.

[0015]

As described above, according to the present invention, even if the water level in the pump is raised to the full water level by the vacuum system and the discharge valve is closed, the horizontal shaft pump avoids a large vibration while avoiding the shutoff operation. And noise can be prevented. Moreover, without using a special pressure source, the differential pressure between the negative pressure and the atmospheric pressure on the suction side of the horizontal axis pump is used to operate the drive means to move the blade gap adjusting member forward and backward. Therefore, the structure is simple, and the initial cost and running cost can be kept low.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of a horizontal shaft pump of the present invention, in which the upper side of the one-dot chain line shows a case where the blade gap adjusting member is brought closer to the impeller to normalize the blade gap, and the one below the one-dot chain line. The side shows the case where the blade gap adjusting member is separated from the impeller to expand the blade gap.

FIG. 2 is a cross-sectional view showing an example in which the relationship between the driving means and the blade gap adjusting member is different.

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

[Explanation of symbols]

 2 vacuum system 3 impeller 4 suction pipe 5 pump casing 6 discharge valve 8 discharge pipe 9 blade gap adjusting member 10 driving means 11 blade gap switching control means

Claims (1)

[Claims] 1. A horizontal shaft pump comprising a vacuum system connected to a suction pipe upstream of an impeller to generate a negative pressure in the suction pipe, and a discharge valve provided in a discharge pipe downstream of the impeller. A vane gap adjusting member movably provided at an inlet of a pump casing accommodating the impeller, a driving unit connected to the vane gap adjusting member, and a suction side of the horizontal shaft pump connected to the driving unit. Negative pressure and atmospheric pressure are loaded to move the blade gap adjusting member in the direction of expansion of the blade gap, and the driving unit is loaded with the negative pressure and atmospheric pressure on the suction side of the horizontal shaft pump. A horizontal axis pump, comprising: a blade clearance switching control means for moving the clearance adjusting member to a normal blade clearance forming position.