JP5075390B2 - pump - Google Patents

Description

  The present invention relates to a household well pump.

  A conventional well pump includes a control device that can control the rotational speed, and includes a pump unit that is directly connected to an electric motor that can change the rotational speed by the control device and incorporates an impeller. The water pumped and pressurized by the pump is sent to the pressure tank and comes out of the faucet through the pipe connected to the pressure tank. At this time, the pump device detects the pressure increasing / decreasing according to the opening degree and the number of uses of the faucet from the signal from the pressure detector, and controls the rotation speed of the electric motor so as to be a constant pressure determined by the control device. An upper limit is set for the rotation speed of the motor so that it can be operated and stopped normally under various installation conditions. When the amount of water exceeds a certain amount, the upper limit of the motor rotation speed is reached and a constant pressure cannot be maintained and the pressure decreases. When the faucet is closed, an increase in pressure is detected and the rotation speed of the motor is reduced to keep the pressure constant. At this time, when the faucet was completely closed, the rotation speed was the minimum for maintaining the pressure, and when the rotation speed was below a certain rotation speed, the pump device was stopped.

JP-A-63-253193

  In the conventional pump device, when the faucet is opened, a decrease in pressure is detected, and the number of revolutions of the electric motor is increased to control the target number of revolutions. The upper limit of the motor rotational speed is determined in consideration of various installation conditions of the pump device so that the electrical load applied to the electric motor and the control device is within an allowable range under the installation conditions where the maximum load is reached.

  For this reason, under the installation conditions where the maximum load is not reached, the set speed of the motor is reached with a low electrical load applied to the motor and the control device, so that the performance of the pump device itself cannot be maximized. Is in a state. Further, even when the control of the pump device is changed in accordance with the installation conditions, there is a problem that the control is periodically changed because the installation conditions are different depending on the water level of the well that changes depending on the season.

  Next, when the well level is deep, when the faucet is opened, a pressure drop is detected, and control is performed so that the rotational speed of the electric motor is increased to the target rotational speed. At this time, if the faucet is further opened, the rotational speed of the electric motor is increased. However, if cavitation occurs before the rotational speed of the electric motor reaches the predetermined upper limit, the pressure and the amount of pumped water are drastically decreased. However, since the control unit of the pump device determines that the pressure is reduced and further increases the motor rotation speed, the cavitation increases accordingly and there is a problem that the operation is performed in a state where the pressure and the pumped water amount are extremely reduced.

Electric load is allowed by the function of detecting the shaft output of the motor in a pump device equipped with a pressure tank that stores pumped water and pressurized water and a pressure detector that detects the discharge pressure of the pump The rotation speed of the motor is controlled so that the shaft output of the motor is maximized within the range. Further, the discharge pressure is controlled to be constant, and when the pumping amount is increased, the rotation speed can be increased until the motor shaft output reaches a predetermined upper limit. In addition, when the discharge pressure is controlled to a constant level and the pumping amount is increased, the motor shaft output that increases with the number of rotations increases, the motor shaft output does not follow the increase in the number of rotations, and the motor shaft output decreases. If this happens, control is performed to reduce the motor speed.

According to the present invention, the pump device is provided with a control device capable of controlling the rotational speed, the electric motor capable of changing the rotational speed by the control device is provided, and the pump unit directly connected to the electric motor and incorporating the impeller is provided. A component for determining the magnitude of the shaft output of the motor is provided inside the control device. It is equipped with a pressure tank that stores pumped and pressurized water and a pressure detector that detects the pump discharge pressure, and is a component that determines the magnitude of the shaft output of the motor. By controlling the rotation speed of the motor so that the shaft output is maximized, first, when the well water level is deep (8m suction height), the rotation speed of the motor is increased to maintain the set discharge pressure. And increase it to the upper limit of the shaft output. The number of rotations at this time is N1, and the amount of water is Q1.

  In addition, since the power consumption of the pump device is higher when the water level is deeper, the conventional pump device sets the upper limit of the rotational speed based on the case where the water level is deep.

Next, in the case the water level in the well is shallow (wicking height 0 m), the amount of water when the driving rotation speed of the motor as N1 is Q2 becomes, Q2-Q1 = ΔQ (2-1 ) is the level difference of the well It becomes the difference in the amount of water that fluctuates.

Next, in the case the water level in the well is shallow, in order to maintain the discharge pressure that has been set, increases the rotational speed to the upper limit value of the shaft output increases the rotational speed of the motor. The rotation speed at this time is N2, N1 <N2, and the water volume at that time is Q3. Q3-Q2 = ΔQ (3-2) is the amount of water increased by increasing the rotation speed.

  For this reason, the amount of ΔQ (3-2) water can be increased compared to the conventional pump device.

  Secondly, when a pressure higher than the set discharge pressure is required and the amount of water is relatively small, the setting is changed and operation is performed at the upper limit value of the motor shaft output.

Next, a control device that can control the rotation speed is provided, an electric motor that can change the rotation speed by the control device is provided, and a pump unit that is directly connected to the motor and incorporates the impeller is provided. A component for determining the magnitude of the shaft output of the motor is provided inside the control device. The pump unit is equipped with a pressure tank that stores water that has been pumped and pressurized, and a pressure detector that detects the pump discharge pressure, and the control device controls the pump discharge pressure to a constant level. In the motor shaft output that increases with the rotational speed that increases when the pumping amount is increased by keeping the pump constant, the well water level can be reduced by following the increase in the rotational speed and lowering the rotational speed by ΔN when the motor shaft output decreases. The set discharge pressure when the pipe diameter is narrow due to geographical conditions, etc., or when the horizontal pulling distance from the well to the pump device becomes long in the piping conditions when the depth is deep (suction height 8m) If the rotational speed of the electric motor is increased to maintain the pressure, cavitation may occur on the suction side of the pump device. At this time, the motor shaft output is extremely reduced. Therefore, if the motor shaft output decreases while the motor rotation speed is increasing, it is determined that the amount of water in the cavitation or well is insufficient, and the rotation speed is decreased by ΔN. As a result, the motor shaft output is increased, and the amount of pumped water can be secured.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a pump device.

  An impeller (not shown) directly connected to the electric motor 2 is watertightly incorporated in the casing 7 and the casing cover 6 to constitute a pump unit 13. A suction port (not shown) and a discharge port (not shown) formed in the casing 7 are provided at the top of the pump unit 13 with a check valve (not shown) through a water sealing material (not shown). The separation chamber 3 having a

  A pressure sensor 4 that detects the pressure pressurized by the pump unit 13 is attached to a discharge pipe 15 that connects the separation chamber 3 and a pressure tank 5 for the purpose of accumulating pressure.

  A control device 20 having an inverter function for controlling the operation of the pump device 1 is configured near the electric motor 2. The control device 20 is supplied with electricity through the power cable 11.

  FIG. 2 shows the flow of the pump device 1.

  A rotation speed sensor 18 for detecting the rotation speed of the electric motor 2 is attached to the opposite side of the pump section 13 of the electric motor 2 connected to the pump section 13. The rotational speed of the electric motor 2 is transmitted from the rotational speed sensor 18 to the control device 20 as an electrical signal.

  The pressure pumped and pressurized by the pump unit 13 is detected by the pressure sensor 4 and transmitted to the control device 20 as an electrical signal. Based on the transmitted signal, the control device 20 controls the rotation speed of the electric motor 2 so that the discharge pressure set in advance is obtained. At this time, a current sensor 19 for detecting a current flowing through the electric motor 2 is provided.

  Further, the control device 20 is provided with a display portion 20a that can display the state of the pump device 1 and an input switch 20b so that an external input is possible.

  FIG. 3 shows a construction state of the pump device 1.

  The pump device 1 pipes a pipe to the suction flange 9 and connects it to the well 90 in a watertight manner. Similarly, the discharge flange 16 is piped to the faucet 89 using a pipe.

  Next, the operation of the pump device 1 will be described.

  When the faucet 89 is opened, water comes out of the faucet 89 due to the pressure in the pressure tank 5. At this time, the pressure sensor 4 detects that the pressure inside the pressure tank 5 is lowered, and the electric motor 2 is started.

  Since the internal pressure of the pump device 1 rises when the electric motor 2 is started, the control device 20 increases or decreases the rotational speed of the electric motor 2 from the signal from the pressure sensor 4 so that the discharge pressure is set.

  As the faucet 89 is closed, the pressure inside the pump device 1 increases, and the rotational speed of the electric motor 2 decreases accordingly, and the pump device 1 finally stops.

  Next, the operation of the present invention will be described.

  The current value, shaft output, and rotation speed data of the motor 2 are input to the control device 20 in advance. The rotation speed and current sensor 19 of the motor to be operated detects the current value and inputs the current value to the control device 20. Can be estimated.

The control device 20 sets an upper limit value of the motor shaft output without particularly setting an upper limit value of the motor rotation speed.
As shown in Fig. 4, the characteristics when the well water level is deep (sucking height 8m)
Curve1-1: Shaft output-Pumped amount
Curve1-2: Rotation speed-Pumped amount
Curve1-3: Expressed as pressure-pumped amount.

  When the faucet 89 is opened and the pressure inside the pump device 1 decreases and the electric motor 2 is started, the control device 20 increases the rotational speed of the electric motor 2 in order to maintain the set discharge pressure. The shaft output reaches the upper limit W1, and then decreases as the pressure decreases at the point X1. The number of rotations at this time is N1, and the amount of water is Q1.

  Further, since the power consumption of the pump device 1 is higher when the water level is deeper, the conventional pump device 1 generally sets the upper limit of the rotational speed based on the case where the water level is deep.

Next, the characteristics when the well level is shallow (the suction height is 0m)
Curve2-1: Shaft output-Pumped amount
Curve2-2: Rotation speed-Pumped amount
Curve1-3: Expressed as pressure-pumped amount.

  When the faucet 89 is opened and the pressure inside the pump device 1 decreases and the electric motor 2 is started, the control device 20 increases the rotational speed of the electric motor 2 in order to maintain the set discharge pressure. The shaft output reaches the upper limit W1, and then decreases in the same way as the pressure decreases at the point X2. The number of rotations at this time is N1, and the amount of water is Q2.

  The amount of water when the motor speed is N1 is Q2, and Q2−Q1 = ΔQ (2-1) is the difference in the amount of water that fluctuates due to the water level difference in the well.

Next, when the well level is shallow, the characteristics of the present invention are
Curve3-1: Shaft output-Pumped amount
Curve3-2: Rotational speed-Pumped amount
Curve3-3: Expressed as pressure-pumped amount.

  When the faucet 89 is opened and the pressure inside the pump device 1 decreases and the electric motor 2 is started, the control device 20 increases the rotational speed of the electric motor 2 in order to maintain the set discharge pressure. When the faucet 89 is further opened to increase the amount of water, the pressure starts to decrease at the point X3 when the number of rotations is increased while the shaft output is increased and maintained to the upper limit value W1. The rotation speed N2 at this time is N1 + ΔN, N1 <N2, and the water amount at that time is Q3. Q3-Q2 = ΔQ (3-2) is the amount of water increased by increasing the rotational speed to the upper limit of the shaft output.

  For this reason, the amount of ΔQ (3-2) water can be increased compared to the conventional pump device.

  Next, in the piping conditions when the well water level is deep (8m suction height), when the pipe diameter is narrowed due to geographical conditions, etc., or when the horizontal pulling distance from the well to the pump device 1 becomes long, When the rotational speed of the electric motor 2 is increased to maintain the set discharge pressure, cavitation may occur on the suction side of the pump device 1. At this time, since the shaft output of the electric motor 2 is extremely reduced, if the shaft output of the electric motor 2 is reduced while the rotational speed of the electric motor 2 is increasing, it is determined that the amount of water in the cavitation or well is insufficient, and the rotational speed is reduced by ΔN. As a result, the shaft output of the electric motor 2 is increased, and the amount of pumped water can be secured.

  Further, when a pressure higher than the set discharge pressure is required and the amount of water is relatively small, the setting is changed to always operate at the upper limit value of the shaft output of the electric motor 2.

  Since the work volume of the pump device 1 can be expressed by coefficient x water volume Q x pressure P, if the water volume is small, increasing the pressure and operating at the upper limit of the motor shaft output will give too much electrical load. High pressure can be obtained.

The external view of the pump apparatus containing this invention. Flow diagram of the pump device. The figure which shows the piping example of a pump apparatus. The figure explaining a pump characteristic.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pump apparatus, 2 ... Electric motor, 3 ... Separation chamber, 4 ... Pressure sensor, 5 ... Pressure tank, 6 ... Casing cover, 7 ... Casing, 8 ... Suction pipe, 9 ... Suction flange, 10 ... Base, 11 ... Power supply Cable, 12 ... Pump cover, 13 ... Pump part, 14 ... Bolt, 15 ... Discharge pipe, 16 ... Discharge flange, 18 ... Revolution sensor, 19 ... Current sensor, 20 ... Control part, 89 ... Water faucet, 90 ... well.

Claims (1)

Provided with a control device capable of controlling the rotation speed, provided with an electric motor capable of changing the rotation speed by the control device, provided with a pump unit directly connected to the electric motor and incorporating an impeller, and detecting the shaft output of the electric motor inside the control device Or a pressure tank for storing the water pumped and pressurized by the pump unit, and a pressure detector for detecting the pump discharge pressure, and the controller discharges the pump discharge pressure. In the pump device that is controlled to be constant,
The pump device is piped to the suction flange and connected to the well in a watertight manner, and the discharge flange is also piped to the faucet using the pipe,
The control device receives the motor current value, shaft output, and rotation speed data, and inputs the motor rotation speed and the current value detected by the current sensor to the control device to thereby output the motor shaft output. Estimate
In the control device, not the upper limit of the rotation speed but the upper limit value of the shaft output is set,
When the pumping height of the pump is small , opening the faucet and detecting the pressure drop inside the pump with the pressure detector, the electric motor is activated, and the control device is configured to maintain the discharge pressure. Increasing the rotational speed of the electric motor, further opening the faucet increases the rotational speed to the upper limit of the shaft output , increasing the rotational speed while maintaining the shaft output of the electric motor ,
When the pumping height of the pump is large , the pump speed is reduced when the shaft output of the motor decreases while the rotation speed of the motor increases.

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