JP3234968B2 - Blade angle self-control type movable blade impeller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a movable blade type pump,
The present invention relates to a blade angle self-controllable movable blade impeller in a fluid device such as a water wheel or a blower.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, an impeller boss 2 fixed to a main shaft 1 and a plurality of impeller blades 4 having a blade shaft 3 non-rotatably mounted on the impeller boss 2 are provided. As shown in FIG. 6, in the fixed-wing type vertical shaft pump provided with the pump, when the pump is operating at or near the highest efficiency point in the open state of the discharge valve 5, the discharge valve 5 is throttled to reduce the discharge amount. When it is reduced, the operating point shifts from A to B, and the hydraulic power loss at the discharge valve 5 increases by an amount corresponding to the increase of the total head, thereby lowering the overall efficiency. Further, although the discharge amount is reduced by narrowing the discharge valve 5, the pump shaft power (consumption shaft power) increases from LA to LB, and in the case of motor driving, the power consumption increases. Here, the overall efficiency is defined as η _T = [{discharge amount × {(total pressure of outlet of discharge valve) − (total pressure of suction cover)) / power consumption of pump shaft] × conversion coefficient.

Therefore, when the discharge amount is reduced by the throttle operation of the discharge valve 5, the hydraulic power loss at the discharge valve 5 is reduced as much as possible, and a decrease in efficiency is avoided. It is desired to realize an operation state in which the power consumption is reduced. However, it cannot be realized with the above-mentioned fixed-wing vertical shaft pump.

On the other hand, as shown in FIGS. 7 and 8, an impeller boss 2 fixed to a main shaft 1 and a blade shaft 3 are connected to the impeller boss 2.
A plurality of impeller blades 4 rotatably mounted around the axis of the blade shaft with respect to the main shaft 1. There is known a movable blade type vertical shaft pump having an operation rod 6, the tip of the operation rod 6 being connected to a blade shaft 3 via a crosshead 7 and a connecting member 8.

In this type of vertical shaft pump, for example, as shown in FIG. 9, the pump is operated at or near the highest efficiency point at an opening angle of the impeller blade 4 of 0 ° with the discharge valve 5 open. During operation, when the discharge valve 5 is throttled and the impeller blades 4 are turned 10 ° to the closing side (minus side), the operating point shifts from A to C, and the pump efficiency curve also shifts, thereby achieving high efficiency. Becomes In addition, the power consumption of the shaft is also reduced from the LA to the LC by reducing the hydraulic power loss at the discharge valve, and the power consumption is reduced when the motor is driven.

On the other hand, in the movable blade type vertical mixed flow pump,
Generally, a load acts to rotate the impeller blades 4 to the closing side by a fluid force in a large water volume region, and a load acts to rotate the impeller blades 4 to an open side by a fluid force in a small water volume region. Also, by changing the thickness of the impeller blades 4 and the like, the moment acting on the blade shaft 3 due to centrifugal force is adjusted,
At the highest efficiency point of the pump at a given vane angle,
It can be said that the moment acting on the blade shaft 3 can be reduced to zero.

The present inventor paid attention to these points, and as a result of diligent research, when reducing the discharge amount by restricting the discharge valve 5, the hydraulic loss at the discharge valve 5 was reduced as much as possible. An operation that avoids a decrease in efficiency and brings the blade axis direction closer to the main axis direction, drastically changes the characteristics of the momentum acting on the blade axis with respect to the water amount, and reduces the power consumption of the shaft due to the decrease in the discharge amount. A blade angle self-controllable movable blade impeller that can realize the state has been proposed.

[0008]

The problem to be solved is that when the discharge amount is reduced by the throttle operation of the discharge valve, the hydraulic power loss at the discharge valve is made as small as possible to avoid a decrease in efficiency, The realization of an operating state in which the consumed shaft power is reduced with a decrease in the discharge amount is impossible with a fixed-wing-type fluid device, and requires a manual operation with a movable-wing-type fluid device.

[0009]

According to the present invention, there is provided an impeller boss fixed to a main shaft and a plurality of wing shafts extending in a radially outward direction of the main shaft so as to be rotatable therearound with the wing shaft. A plurality of impeller blades attached to the impeller boss, a crosshead externally rotatably fitted to a center boss portion of the impeller boss, and a cross axis and a blade axis of the impeller blade. And a connecting member that converts the rotation of the impeller blade around the blade axis by the fluid force into the rotation of the crosshead in the circumferential direction and transmits the rotation.
Even if the discharge amount is adjusted by the throttle operation of the discharge valve, the blade angle is self-controlled according to the adjusted discharge amount.
The objective was to reduce the hydraulic power loss at the discharge valve when reducing the discharge rate, and to reduce energy consumption by reducing the power consumption of the shaft.

[0010]

According to the present invention, when the discharge amount is adjusted by opening and closing the discharge valve, the plurality of impeller blades are turned to the open side or the close side by the fluid force corresponding to the adjusted discharge amount, and the centrifugal force is increased. Is added, and the attitude of the impeller blade can be specified at the blade angle at which the moment acting on the blade axis becomes zero. The rotation of each impeller blade and the blade shaft around the blade axis is transmitted to the crosshead via the connecting member and rotates the crosshead in the circumferential direction, so that the plurality of impeller blades open or close. The side has a fixed blade angle with the same blade angle, that is, a blade angle at which the blade axis moment near the highest efficiency point becomes zero, corresponding to the discharge amount adjusted by the opening / closing operation of the discharge valve.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view of a vertical mixed flow pump provided with the present invention, and FIG. 2 is an enlarged sectional view of a main part. The same or corresponding parts as those in the conventional example shown in FIGS. 5 to 9 are denoted by the same reference numerals. 1 and 2, the vertical mixed-flow pump includes an impeller boss 2 fixed to a main shaft 1 and a main shaft 1.
A plurality of (for example, four) impeller blades 4 (FIG. 1) attached to the impeller boss 2 so as to be rotatable therearound along with the plurality of blade shafts 3 extending in the radial direction.
And FIG. 2 shows only two impeller blades 4), and a crosshead 9 is fitted to the center boss portion 2A of the impeller boss 2 so as to be rotatable in the circumferential direction. .

The crosshead 9 is connected to the four
Connected to the three blade shafts 3. That is, as shown in FIG. 3, four screw holes 9A, 9A... Are formed in the crosshead 9 at equal intervals in the circumferential direction in the radial direction. Screw holes 3A, 3A
.. Are formed. On the other hand, the connecting member 8 is formed of a universal joint having a pair of ball joints 8A and 8B, and has a male screw 8a formed at one end and a male screw 8b formed at the other end.
Are formed. Then, the male screw 8a is screwed into the screw hole 3A of each blade shaft 3, and the male screw 8b is screwed into the screw hole 9A of the crosshead 9, whereby the crosshead 9 is connected to the four blade shafts 3 via the connecting member 8. It is connected to the structure.

With such a configuration, the discharge valve 5 shown in FIG.
When the discharge amount is adjusted by the opening and closing operation of the above, the plurality of impeller blades 4 are turned to the open side or the close side by the fluid force corresponding to the adjusted discharge amount, and the moment acting on the blade shaft 3 together with the centrifugal force is increased. The attitude of the impeller blade 4 can be specified at a blade angle of zero.
The rotation of each impeller blade 4 and the blade shaft 3 around the blade axis is transmitted to the crosshead 9 via the connecting member 8 and rotates the crosshead 9 in its circumferential direction. 4 is the same blade angle on the opening side or the closing side, that is, the discharge valve 5
Adapting to the discharge rate adjusted by the opening / closing operation, the blade axis moment near the highest efficiency point is fixed with a blade angle at which the blade moment becomes zero.

As an example, in FIGS. 1 and 4, when the pump is operated (A) at or near the highest efficiency point at the opening angle of the impeller blade 4 of 0 ° with the discharge valve 5 open. When the discharge valve 5 is throttled, the plurality of impeller blades 4 are both rotated to the closing side (minus side) by the fluid force corresponding to the throttled discharge amount. The rotation of the blade shaft 3 at this time is transmitted to the crosshead 9 via the connecting member 8 and rotates the crosshead 9 in its circumferential direction.
Are fixed with the same wing angle on the closed side. In this case, the operating point shifts from A to C, and the hydraulic head loss at the discharge valve 5 is reduced by an amount corresponding to the decrease in the total head as compared with B, so that the overall efficiency becomes high. In addition, the consumption shaft power is also L
From A to LC, the power consumption is reduced in the case of motor drive. That is, the pump efficiency is high in a wide range of the pump efficiency.

The present invention is not limited to a mixed flow pump or an axial flow pump, but can be applied to a movable blade fluid device such as a water wheel or a blower.

[0016]

As described above, according to the present invention, when the discharge amount is reduced by the throttling operation of the discharge valve, the hydraulic loss at the discharge valve is reduced as much as possible, and the reduction in the discharge amount is avoided. As a result, it is possible to realize an operation state in which the consumed shaft power is reduced with a decrease in the power consumption.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a vertical mixed flow pump provided with an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part.

FIG. 3 is a diagram viewed from an arrow in FIG. 2;

FIG. 4 is a diagram showing operating characteristics of the present invention.

FIG. 5 is a vertical sectional view showing an example of a fixed blade type vertical shaft pump.

FIG. 6 is a diagram showing operating characteristics of a fixed-wing type vertical shaft pump.

FIG. 7 is a longitudinal sectional view showing an example of a movable blade type vertical shaft pump.

FIG. 8 is a perspective view showing a relationship between an impeller and an operation rod.

FIG. 9 is a diagram showing operating characteristics of a movable blade type vertical shaft pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main shaft 2 Impeller boss 2A Center boss part of impeller boss 3 Blade shaft 4 Impeller blade 8 Connecting member 9 Crosshead

Claims (1)

(57) [Claims] 1. An impeller boss fixed to a main shaft, and a plurality of impeller bosses rotatably mounted on the impeller via a plurality of wing shafts extending radially outward of the main shaft. Impeller blades, a crosshead externally rotatably fitted to the center boss portion of the impeller boss, and connecting the crosshead and the blade axis of the impeller blade to each other, and using fluid force. A self-controlled movable blade impeller, comprising: a connecting member that converts rotation of the impeller blades around the blade axis into rotation of the crosshead in the circumferential direction and transmits the rotation.