JP3234969B2 - How to control the rotation speed of the drainage pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the rotation speed of a drainage pump.

[0002]

2. Description of the Related Art Conventionally, a main shaft 2A of a drainage pump (for example, a vertical shaft volute pump) 2 installed in a water absorption well 1 shown in FIG.
A drain pump unit having a structure in which an output rotary shaft of a speed reducer 3 is connected to an output rotary shaft of a prime mover 6 composed of, for example, a diesel engine via a coupling 4 and a clutch 5; Alternatively, as shown in FIG.
A drain pump having a structure in which the output rotary shaft of a compound reducer 8 incorporating the same is connected, and the input rotary shaft of the compound reducer 8 is connected via a coupling 4 to the output rotary shaft of a prime mover 6 made of, for example, a diesel engine. Equipment is known.

In this type of drainage pump equipment, the output of the prime mover 6 is transmitted to the main shaft 2A of the drainage pump 2 via the speed reducer 3 or the composite speed reducer 8 and the drainage pump 2 is driven to perform a drainage operation. . Specifically, at the time of normal drainage such as heavy rainfall or normal rainfall, the rainwater flowing into the water intake well 1 from the river is drained by the rated operation of the motor 6. However, when the drainage pump 2 is driven by the rated operation of the prime mover 6 to drain the water even when the amount of water flowing from the river into the water absorption well 1 is small or when there is very little rainfall, the amount of water discharged from the water pump 2 flows into the water absorption well 1. It will be much higher than the water volume. As a result, when the water level of the water absorption well 1 rises to the operation start water level and the drainage operation of the drainage pump 2 is started, the water level of the water absorption well 1 rapidly decreases, rises again, and immediately starts operation. Will start to repeat.
In the worst case, the water level becomes lower than the operable water level, the air is sucked into the pump, and large vibrations and noises are generated, which causes various inconveniences on the drainage pump 2 and the drainage pump equipment.

Therefore,. A discharge valve control method for controlling the opening degree of a discharge valve provided on the discharge side of the drain pump 2;
A movable blade type in which the impeller blades of the drainage pump 2 are made to have a movable structure, and the opening degree of the impeller blades is controlled to adjust the drainage amount; It is conceivable that the amount of drainage at the time of light rainfall is suppressed by a rotation speed control method for controlling the output rotation speed of the prime mover 6 to avoid the above-mentioned inconvenience.

[0005] However, in the large capacity drainage pump 2,
In many cases, the use of the discharge valve is omitted and cannot be controlled by the above-described discharge valve control method. Even if a discharge valve is used, it takes a long time to open and close the discharge valve, and it cannot cope with a sudden flood. That is, there is a disadvantage that the response is poor. Further, the above-mentioned movable blade system has a drawback that the structure of the movable blade drive mechanism for controlling the opening degree of the impeller blade is complicated, and the cost is increased. Further, in the rotation speed control method for controlling the output rotation speed of the prime mover 6, when the prime mover 6 composed of a diesel engine is used, for example, by continuing the light load operation by low-speed operation, abnormal combustion peculiar to the diesel engine is performed. (Diesel knock), incomplete combustion, etc., causing the carbon to adhere and the number of overhauls of the engine to increase.
If the rotational speed is reduced below, there is a possibility that torsional vibration of the engine may occur, and there is a disadvantage that the rotational speed cannot be reduced to about 70% N or less. This is true even when the prime mover 6 including the gas turbine engine is used. That is, in the above-mentioned and methods, it is not possible to effectively suppress the amount of drainage at the time of light rainfall and at the time of very little rainfall with a simple structure and good responsiveness, and to reliably avoid the above-mentioned inconvenience.

On the other hand, when the compound speed reducer 8 incorporating the variable speed fluid coupling 7 is used, the input rotation is performed by moving the squeeze pipe 70 of the variable speed fluid coupling 7 forward and backward by the speed change operation rod (control rod) 71. The output rotation speed can be reduced to about 30% N of the number. However, even if it is reduced to 70% N by the prime mover 6 composed of a diesel engine and to 30% N by the variable speed fluid coupling 7 of the composite reduction gear 8, (0.7) × (0.3) = 0 .
21, that is, the limit is to reduce the rotation speed of the main shaft 2A of the drainage pump 2 to approximately 21% N of the rated rotation speed of the prime mover 6.

Therefore, as shown in FIG. 5, two variable speed fluid couplings 7A and 7B are provided in series in a power transmission system extending from the output rotary shaft 6A of the prime mover 6 to the main shaft 2A of the drainage pump 2. Thus, it is proposed that the rotational speed of the main shaft 2A be significantly reduced in total, including the decrease in the rotational speed by the control of the variable speed fluid coupling 7A and the decrease in the rotational speed by the control of the variable speed fluid coupling 7B. However, as described above, the variable speed fluid couplings 7A and 7B are separately provided with the squeeze pipe 70 and the speed change operation rod 71, and the speed change operation rods 71 are moved forward and backward by the separate control motors 10 and 10, respectively. It is configured as follows. Therefore, when controlling the two variable speed fluid couplings 7A, 7B, the variable speed fluid couplings 7A, 7
It is necessary to independently move the speed change operation rods 71 of each of the B types. That is, the individual control motors 10, 1
The operation of inputting a separate control signal to 0 is cumbersome in operation and is inferior in stability.

As a specific example, two variable speed fluid couplings 7
When it is desired to reduce the total number of revolutions to 36% N by the control of A and 7B, various combinations can be selected. That is. A combination of controlling the variable speed fluid coupling 7A to 40% N and controlling the variable speed fluid coupling 7B to 90% N, controlling the variable speed fluid coupling 7A to 50% N, and controlling the variable speed fluid coupling 7B to 72% N Or the variable speed fluid coupling 7A is controlled to 60% N and the variable speed fluid coupling 7B is controlled to 60% N
It can be executed by a combination or the like controlled to Therefore, one of the combinations is selected, and the forward / backward movement amount of the speed change operation rod 71 of the variable speed fluid coupling 7A and the forward / backward movement amount of the speed change operation rod 71 of the variable speed fluid coupling 7B in the selected combination are The setting must be made by inputting separate control signals to the individual control motors 10, 10.

[0009]

The problem to be solved is that a plurality of variable speed fluid couplings are interposed in series in a power transmission system from the output rotation shaft of the prime mover to the main shaft of the drain pump. Although the number of rotations of the main shaft can be greatly reduced, the amount of forward / backward movement of the speed change operation rod of each of the plurality of variable speed fluid couplings has a troublesome operation of inputting separate control signals to a plurality of control motors. This is inferior in stability.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a method for controlling the number of rotations of a drain pump in which a plurality of variable speed fluid couplings are interposed in series in a power transmission system from an output rotary shaft of a prime mover to a main shaft of the drain pump. The speed change operation rods of the plurality of variable speed fluid couplings are connected to the output rotation shaft of one control motor via a power transmission mechanism so that the speed change operation rods simultaneously move forward and backward by the same amount. By inputting a control signal to one control motor, the speed change operation rods of a plurality of variable speed fluid couplings are simultaneously controlled to the same value, thereby controlling the rotation speed of the drain pump. The goal of improving operability and stability has been achieved.

[0011]

According to the present invention, a control signal corresponding to the total control value of a plurality of variable speed fluid couplings is input to one control motor, so that the control motor is controlled by a predetermined amount in either the forward or reverse direction. Rotates, and this rotation simultaneously moves the speed change operation rods of the plurality of variable speed fluid couplings forward and backward by the same amount via the power transmission mechanism, and simultaneously controls the plurality of variable speed fluid couplings at a value corresponding to the total control value. be able to.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, in the drainage pump equipment, an output rotary shaft 3A of a speed reducer 3 is connected to a main shaft 2A of a drainage pump (for example, a vertical shaft centrifugal pump) 2 installed in a suction well 1.
The input rotary shaft 3B of the speed reducer 3 is connected via a first coupling 4A, a first variable speed fluid coupling 7A, a second coupling 4B, a second variable speed fluid coupling 7B and a third coupling 4C arranged in series. For example, it is connected to an output rotation shaft 6A of a main motor 6 composed of a diesel engine.

As shown in FIG. 2, the first variable speed fluid coupling 7A and the second variable speed fluid coupling 7B have an impeller 12 fixed to an input shaft 11, a runner 14 fixed to an output shaft 13, and And the runner 14 are concentrically opposed to each other, and hydraulic oil is supplied to a space between the impeller 12 and the runner 14 by a hydraulic oil supply system 15 including an oil tank 15A, an oil cooler 15B, and an oil pump 15C. It is swirled in the working chamber 17 surrounded by 16 and returned to the oil tank 15A through the squeeze pipe 70. The squeeze pipe 70 is connected to a shift operation rod 71 that can move forward and backward. Therefore, the amount of oil in the working chamber 17 is determined by moving the squeeze pipe 70 forward and backward in the working chamber 17 with the forward and backward movement of the speed change operation rod 71,
The rotation speed of the output shaft 13 is configured to be continuously controllable in a range from 100% N to 30% N.

The speed change operation rod 71 of each of the variable speed fluid couplings 7A and 7B is connected via a power transmission mechanism 9 to an output rotary shaft 10A of a control motor 10 composed of one servo motor, for example. The power transmission mechanism 9
As shown in FIG. 3, an intermediate gear 90 fixed to the output rotation shaft 10A of the control motor 10, this intermediate gear 90
The first gear 91A meshing with the first gear 91A is fixed, and the first rotating shaft 92A rotatably and axially immovably supported and the second gear 91B meshing with the intermediate gear 90 are fixed and rotatable and fixed. Second rotating shaft 9 that is supported so that it cannot move in the direction
2B, a male screw 92a is formed on a part of the outer periphery of the first rotating shaft 92A, and a male screw 92b formed by a screw opposite to the male screw 92a is formed on a part of the outer periphery of the second rotating shaft 92B.
Are formed. The male screw 92a of the first rotating shaft 92A is screwed into the female screw 93a of the first moving shaft 93A, and the male screw 92b of the second rotating shaft 92B is screwed into the female screw 93b of the second moving shaft 93B. The speed change operation rod 71 of the variable speed fluid coupling 7A is connected to the first movement cylinder 93A, and the speed change operation rod 71 of the variable speed fluid coupling 7B is connected to the second movement cylinder 93B.

In the above configuration, the variable speed fluid coupling 7A,
By inputting a control signal corresponding to the total control value of the control motor 7B to the control motor 10, the control motor 10 rotates by a predetermined amount in either the forward or reverse direction. It is simultaneously transmitted to the speed change operation rod 71 of the joints 7A and 7B and the squeeze pipe 70.
In other words, the intermediate gear 90 → the first gear 91A →
Rotates the first rotating shaft 92A along the path of the intermediate gear 90 → the second gear 91B → the second rotating shaft 92B
Are rotated in the reverse direction so that the first rotation shaft 92A and the second rotation shaft 92
B moves forward and backward in the same direction, and the variable speed fluid couplings 7A, 7A
The B shift operation rod 71 and the squeeze pipe 70 are simultaneously moved in the same direction by the same amount.

That is, the variable speed fluid couplings 7A and 7B can be simultaneously controlled with a value corresponding to the total control value. As a specific example, when it is desired to reduce the total rotation speed to 36% N by controlling the variable speed fluid couplings 7A and 7B, a control signal corresponding to the total control value of the variable speed fluid couplings 7A and 7B is input to the control motor 10. By doing so, the variable speed fluid coupling 7A can be controlled to 60% N, and the variable speed fluid coupling 7B can be controlled to 60% N, so that the total rotational speed can be easily and reliably reduced to 36% N. Operability and stability when controlling the rotation speed of the drain pump 2 are improved.

In the embodiment, the first variable speed fluid coupling 9 and the second variable speed fluid coupling 10 are connected in series between the input rotary shaft 3B of the speed reducer 3 and the output rotary shaft 6A of the prime mover 6. As shown in FIG. 4, a composite speed reducer 8 incorporating a second variable speed fluid coupling 10 is used, and the input rotary shaft 8B of the composite speed reducer 8 and the prime mover 6 are used. The first variable speed fluid coupling 9 may be interposed between the output rotary shafts 6A.

[0018]

As described above, according to the present invention,
By inputting a control signal corresponding to the total control value of a plurality of variable speed fluid couplings to one control motor, the shift operation rods of the plurality of variable speed fluid couplings are simultaneously advanced and retracted by the same amount via a power transmission mechanism. Since the plurality of variable speed fluid couplings can be moved and controlled simultaneously at a value corresponding to the total control value, the operation at the time of controlling the rotation speed of the drainage pump is facilitated, and the operability and stability are improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating an example of a variable speed fluid coupling.

FIG. 3 is a configuration diagram illustrating an example of a power transmission mechanism.

FIG. 4 is a configuration diagram showing a modification of the present invention.

FIG. 5 is a configuration diagram showing a comparative example.

FIG. 6 is a configuration diagram showing a conventional example.

FIG. 7 is a configuration diagram showing another conventional example.

[Description of Signs] 2 Drain pump 2A Main shaft of drain pump 6 Primer 6A Output rotary shaft of prime mover 7A First variable speed fluid coupling 7B Second variable speed fluid coupling 9 Power transmission mechanism 10 Control motor 10A Output rotary shaft of control motor 71 Speed change rod

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-77191 (JP, A) JP-A-53-4156 (JP, A) JP-A-55-135263 (JP, A) JP-A-62 101922 (JP, A) Japanese Utility Model Showa 56-27428 (JP, U) Japanese Utility Model Showa 62-105394 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04D 13/02 F04D 15 / 00 F04D 29/04 F16D 31/00

Claims (1)

(57) [Claims] 1. A method for controlling the number of rotations of a drain pump, comprising a plurality of variable speed fluid couplings arranged in series in a power transmission system from an output rotary shaft of a prime mover to a main shaft of the drain pump. The speed change operation rod of the fluid coupling is connected to the output rotation shaft of one control motor via a power transmission mechanism, so that a plurality of speed change operation rods are simultaneously moved forward and backward by the same amount. Drainage pump rotation speed control method.