JPH08318260A - Drainage control device - Google Patents

Abstract

(57) [Summary] [Purpose] Drain a specified flow rate at each water level without using a regulating tank. [Structure] The water level of the sewage 6b stored in the water storage tank 1 is measured by a water level measuring means 9, and the pump control device 10 causes the sewage to have a required drainage capacity required to discharge a predetermined flow rate at each water level. By controlling the drainage capacity of the pump 7, it is possible to drain water at a predetermined flow rate without using an adjusting tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drainage control device, and more particularly to a drainage control device for a domestic wastewater treatment device.

[0002]

2. Description of the Related Art In a sewage treatment apparatus, it is desirable that the flow rate of drainage water from a water storage tank to an aeration tank be controlled to a predetermined amount according to the treatment capacity of the aeration tank. As a drainage control device for this purpose, as disclosed in JP-A-60-168592, it has been proposed to install an adjusting tank between the water storage tank and the aeration tank. This drainage control device adjusts the drainage amount of the wastewater pump that transfers the wastewater accumulated in the water storage tank to the aeration tank to the aeration tank by the adjustment tank so that the drainage amount changes depending on the specifications of the equipment and the water level. Therefore, the excess water pumped into the adjustment tank is returned to the water storage tank. The sewage pump is controlled by a high water level float switch and a low water level float switch that detect the water level in the water tank.When the high water level float switch is activated, drainage operation is started, and when the low water level float switch is activated, drainage operation is stopped. To do.

This drainage control device has an advantage that a wastewater pump can be standardized for a plurality of types of wastewater treatment devices.

[0004]

A sewage treatment apparatus for treating domestic miscellaneous wastewater is one of a plurality of types of water storage tanks having a size corresponding to the amount of wastewater, for example, 50 person tank, 100 person tank, 150 person tank.
It is equipped with one of the water tanks, such as the human tank and the 200-person tank, and the aeration tank of a suitable scale. Therefore, a trader who installs such a sewage treatment apparatus using the above-described wastewater control device needs to prepare a plurality of types of adjustment tanks corresponding to these treatment scales in order to control the amount of wastewater. Yes, inventory management is troublesome and uneconomical.

An object of the present invention is to provide a drainage control device capable of draining a predetermined amount of water from a water storage tank without using such an adjustment tank.

[0006]

One of the features of the present invention is as follows.
In a drainage control device comprising a water storage means for storing water, a drainage means for draining the water from the water storage means, and a drainage control means for controlling the drainage means, the drainage control means includes a water level of the water stored in the water storage means. A water level measuring means for measuring the water level, a water level data fetched from the water level measuring means, and a required drainage capacity calculating means for calculating a required drainage capacity necessary for draining a predetermined flow rate at the water level; A control signal generating means for generating a control signal converted into a capacity control amount for obtaining a required drainage capacity, and a drainage variable control means for controlling the drainage capacity of the drainage means by the control signal are provided. .

Another feature of the present invention is a drainage control device comprising a water storage tank for storing wastewater, a wastewater pump for draining the wastewater from the water storage tank, and a pump control device for controlling the wastewater pump, The pump control device takes in water level measuring means for measuring the water level in the water tank and water level data from the water level measuring means, calculates the required drainage capacity necessary for draining a predetermined flow rate at the water level, and controls the required drainage capacity. Control signal generating means for generating a signal, and pump variable control means for controlling the drainage capacity of the wastewater pump based on the required drainage capacity control signal are provided.

As the water level measuring means, an ultrasonic sensor for measuring the distance from the upper part of the water tank to the water surface is used, or a water pressure measuring means installed in the water tank is used.

The drainage capacity computing means fetches the water level data at predetermined time intervals to compute the required drainage capacity.

The drainage means is an electric pump, and the drainage variable control means controls the rotation speed of the electric pump.

Further, the drainage control means drains the drainage means at a water level within a predetermined range.

[0012]

The water level measuring means measures the water level of the water storage means, and the required drainage capacity computing means fetches the water level data from the water level measuring means and computes the required drainage capacity necessary for draining a predetermined flow rate at the water level. Then, the control signal generation means generates a control signal converted into a capacity control amount for obtaining the required drainage capacity in the drainage means, and the drainage variable control means uses the control signal to change the drainage capacity of the drainage means to a required drainage flow rate. Control so that.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram showing a sewage treatment apparatus according to the present invention. As shown in the figure, a general sewage treatment apparatus includes a water storage tank 1, an aeration tank 2, a settling tank 3 and a disinfection tank 4, and the drainage control apparatus according to the present invention is a storage water located at the first stage of the sewage treatment apparatus. Used for wastewater treatment from tank 1 to aeration tank 2. The water storage tank 1 temporarily stores miscellaneous wastewater (sewage) 6a flowing from each household through the wastewater pipe 5. The sewage pump 7 pumps up the sewage 6b stored in the water storage tank 1 and discharges it to the aeration tank 2 through the drain pipe 8 (6c). The drainage control device includes a water storage tank 1, a sewage pump 7, a water level measuring means 9, and a pump control device 10.

The pump control device 10 in this drainage control device monitors the water level of the sewage 6b stored in the water tank 1 on the basis of the water level detection signal (water level data) obtained from the water level measuring means 9, and the inside of the water tank 1 is monitored. The drainage capacity of the wastewater pump 7 is controlled so that the water level of the wastewater 6b falls within a predetermined range and the inflow amount of the wastewater 6c discharged to the aeration tank 2 becomes an amount suitable for the aeration treatment capacity of the aeration tank 2. The water level measuring means 9
For example, an ultrasonic distance sensor installed on the top plate 1a of the water tank 1 measures the distance (water level) to the dirty surface in the water tank 1 and outputs the water level detection signal (water level data). To do. The water level measuring means 9 can be configured by using a water pressure sensor (water pressure measuring means) installed in the water tank, a float switch, or the like, in addition to the distance sensor. The pump control device 10 is mainly composed of a microcomputer, and periodically takes in the distance (water level) detection signal output from the water level measuring means 9 at a predetermined time interval to obtain the water level of the dirty water 6b in the water tank 1. And calculates the required drainage capacity of the sewage pump 7 required to drain the sewage 6b in the water storage tank 1 to the aeration tank 2 at a predetermined flow rate at each water level,
The pump rotation speed (rotation speed) that exerts the drainage capacity is calculated, and the rotation speed of the drive motor that drives the wastewater pump 7 is controlled to be the pump rotation speed.

FIG. 2 is a block diagram showing an embodiment of such a pump control device 10. Pump control device 10
Is connected to the AC power supply 12 via the power cord 11,
The high voltage rectified by the rectifier circuit 13 is smoothed by the smoothing capacitor 14, and the power conversion circuit 1 is connected via the load current detection resistor 15.
6, a variable AC voltage is generated by the power conversion circuit 16 and is supplied to the drive motor 7a of the wastewater pump 7. The drive motor 7a has a configuration in which the rotation speed is changed by performing PWM control of the supplied variable AC voltage, and is an encoder or F that generates a rotation speed (encoder) signal.
G (not shown) is provided to drive the pump 7b.

The protection circuit 17 includes the load current detection resistor 1
The voltage drop generated at 5 is input, the load state is detected from the magnitude thereof, and an overload signal is generated if an overload state occurs.

The control microcomputer 18 comprises a control signal generating means 18a, a drainage amount calculating means 18b, a time measuring means 18c and a time storing means 18d. Each of these means is realized by a CPU, a memory, and a program. Then, the control microcomputer 18 takes in the water level detection signal output from the water level measuring means 9 and the overload signal and the encoder signal output from the protection circuit 17, so that the pump 7b has a predetermined drainage amount (drainage capacity). The rotation speed control of the drive motor 7a is executed so that the rotation speed becomes as follows. Specifically, the control microcomputer 18 calculates the required number of revolutions required for the sewage pump 7 to have a predetermined amount of drainage at the water level based on the water level detection signal, and the actual number of revolutions detected by the encoder signal is calculated. A PWM control signal for correcting and controlling the rotation speed of the drive motor 7a so as to be equal to the required rotation speed is generated.

The variable control circuit 19 PWM-controls the output voltage supplied from the power conversion circuit 16 to the drive motor 7a based on the PWM control signal supplied from the control microcomputer 18.

Next, the relationship between the drainage head height of the sewage pump 7 and the amount of drainage will be described with reference to FIG. The sewage pump 7 is
It is started when the water level in the water storage tank 1 reaches the height H (cm), and 50 cm is drained until it reaches h (cm).
For example, the ideal amount of waste water in a sewage treatment apparatus using the water storage tank 1 of 50 people is 7 liters / minute. At a pumping height H (100 cm) at which the sewage pump 7 is activated, the sewage pump 7 can obtain a drainage capacity of a predetermined drainage amount (7 liters / minute) at 1500 rpm, but the drainage amount decreases as the water level decreases (the pumping height increases). Therefore, in order to maintain 7 liters / minute, it is necessary to increase the rotation speed as the water level decreases. At a height of h (150 cm), which is the water level immediately before the sewage pump 7 is stopped, the sewage pump cannot maintain a predetermined drainage rate unless it is rotated at 1650 rpm. With this drainage characteristic, the speed increase rate in the pumping height range (H-h) in which the sewage pump 7 operates is 3 {= (1650-1500) ÷ 50} rp.
m / cm.

The pump control device 10 calculates, as an offset rotation speed, the rotation speed required to correct the change in the drainage amount due to the change amount of the water level (lift height) based on the water level detection signal fetched from the water level measuring means 9. The offset rotation speed is added to the reference rotation speed (rotation speed at startup) to control the rotation speed of the drive motor 7a so as to maintain a predetermined drainage amount.

FIGS. 4 and 5 show the sewage pump 7 as described above.
The control process of the control microcomputer 18 in the pump control device 10 for controlling the drive motor 7a of FIG.

When the power is turned on, the control microcomputer 18 performs initial processing in step 101. The size of the water tank 1 is usually 50 people, 10 people.
There are four types: 0 person tank, 150 person tank and 200 person tank. The ideal drainage to the next stage aeration tank 2 is 7 liters / minute for 50 person tank, 14 liter / minute for 100 person tank, 150 It is 21 liters / minute for a human tank and 28 liters / minute for a 200 person tank. Further, the sewage pump 7 has a head height H at startup.
= 100 (cm), the number of rotations that exerts the drainage capacity to obtain the respective drainage amounts is about 1500 rpm, 1600 rpm,
1700 rpm and 1800 rpm, and the speed increase rate is 3 rpm / c in the head height range (H-h).
m, each of these data is stored in advance in the control microcomputer 18.

In steps 102 to 104, it is determined what kind of water storage tank 1 the waste water treatment device uses, and steps 105 to 10 corresponding to the size of the water storage tank 1 (ideal discharge amount).
Move to 8 and set the reference speed. This reference speed is
As described above, this is the initial rotation speed when the dirty water pump 7 (drive motor 7a) is started when the water level becomes H (cm). The information indicating what kind of water storage device 1 uses the waste water treatment device 1 is set in advance when the device is installed.

Next, the control microcomputer 18
In step 109, the water level detection signal (water level data) output from the water level measuring means 9 is fetched, and in step 110, it is compared and judged whether the water level is lower than H (cm). If the water level is higher than H (cm), the process returns to step 109 to fetch the water level data, and if the water level is lower than H (cm), step 111 is executed.
Then, a delay process for generating a predetermined interval (4 ms) for taking in the water level data is executed. When the predetermined delay time has elapsed, the routine proceeds to step 112, where the rotation speed conversion processing is performed.

FIG. 5 shows details of the rotation speed conversion process 112. In this embodiment, the rotation speed of the sewage pump 7 is calculated according to the following equation.

Rotational speed = reference rotational speed + {(water level data-starting head height) × 3 rpm} (1) For example, in a 50-person tank, the starting head height for starting drainage operation is 100 (cm), and The rotation speed of the sewage pump 7 that obtains a predetermined amount of drainage at the water level is 1500 rpm. And the water level (lift height) at which the drainage operation is stopped is 1
It is 50 (cm), and the rotation speed of the sewage pump 7 that obtains a predetermined amount of drainage at the water level is 1650 rpm. Normally, when the wastewater pump 7 is operated for drainage, the water level in the water storage tank 1 is lowered, but the amount of drainage water from each household is large and the water storage tank 1
When the inflow amount of the sewage 6 that flows into the water is larger than the drainage amount of the sewage pump 1, the water level rises. The above calculation formula can be directly applied even in such a case.

First, in step 112a, water level data is loaded. Next, in step 112b, the starting lift height H = 100 (cm) is loaded. Then, in step 112c, {(water level data-starting head height) × 3 rpm} is calculated to obtain offset data (rotation speed), and the process proceeds to step 112d to store the offset data in the memory. In step 112e, the reference rotation speed (= 1500 rpm) is loaded, and in step 112f, the offset rotation speed is added to the reference rotation speed to obtain the required rotation speed of the sewage pump 7. Then, in step 112g, the required rotation speed is stored in the memory.

Next, returning to the processing of FIG. 4, step 113
In step 114, the required rotation speed is set as a command speed for the drive motor 7a, and in step 114, power conversion processing is performed to generate a voltage to be supplied to the drive motor 7a so that the rotation speed of the drive motor 7a becomes the command speed.

In step 115, the water level detection signal is fetched, and in step 16, it is compared and judged whether the water level is lower than h (cm). If the water level is lower than h (cm), move to step 117 and drive motor 7a.
Step 10 to stop drainage by the water pump 7
Returning to step 9, if it is higher than h (cm), the process returns to step 111 to execute the delay process, and then moves to step 112 to perform the rotation speed conversion process.

The delay processing 111 for generating the sampling interval for fetching and processing the water level detection signal is performed by using the time measuring means 18c and the time storing means 18d.

According to such a sewage pump rotation speed control, the sewage pump 7a controls the sewage 6 stored in the water storage tank 1 such that the water level (lift height) is within the range of 100 to 150 (cm). It is possible to perform drainage operation with a predetermined amount of drainage at each water level.

Although the embodiment applied to the sewage treatment apparatus has been described above, the present invention can be applied to other water (liquid) treatment apparatuses.

[0034]

INDUSTRIAL APPLICABILITY The present invention measures the water level of the water stored in the water storage means and adjusts the drainage capacity of the drainage means so that the required drainage capacity is achieved to drain a predetermined flow rate at each measured water level. Since it is controlled, it is possible to drain water at a predetermined flow rate without using an adjusting tank.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a sewage treatment apparatus according to the present invention.

FIG. 2 is a block diagram showing an embodiment of a pump control device according to the present invention applied to the wastewater treatment device shown in FIG.

FIG. 3 is a characteristic graph showing the relationship between the drainage head height of a sewage pump and the amount of drainage.

4 is a flowchart of drainage control processing in the pump control device shown in FIG.

5 is a detailed process flowchart of a rotation speed conversion process in the drainage control process shown in FIG.

[Explanation of symbols]

 1 Water Storage Tank 2 Aeration Tank 3 Precipitation Tank 4 Disinfection Tank 5 Sewage Pipe 6a to 6c Miscellaneous Wastewater (Sewage) 7 Sewage Pump 7a Drive Motor 7b Pump 9 Water Level Measuring Unit 10 Pump Control Device 16 Power Conversion Circuit 18 Control Microcomputer 19 Variable Control circuit

Claims (9)

[Claims] 1. A drainage control device comprising water storage means for storing water, drainage means for draining the water from the water storage means, and drainage control means for controlling the drainage means, wherein the drainage control means collects water in the water storage means. A water level measuring means for measuring the water level of the obtained water, and a required drainage capacity amount calculating means for calculating the required drainage capacity necessary for draining the water level data from the water level measuring means and discharging a predetermined flow rate at the water level, The drainage means comprises control signal generating means for generating a control signal converted into a capacity control amount for obtaining the required drainage capacity, and drainage variable control means for controlling the drainage capacity of the drainage means by the control signal. A drainage control device characterized in that 2. The drainage control device according to claim 1, wherein the water storage means is a water storage tank, and the water level measurement means is an ultrasonic sensor for measuring the distance from the upper part of the water storage tank to the water surface. . 3. The drainage control device according to claim 1, wherein the water storage means is a water storage tank, and the water level measurement means is a water pressure measurement means installed in the water storage tank. 4. The drainage control device according to claim 1, wherein the drainage capacity calculating means calculates the required drainage capacity by taking in the water level data at every predetermined time. 5. The drainage control device according to claim 1, wherein the drainage means is an electric pump, and the drainage variable control means controls a rotation speed of the electric pump. 6. The drainage control means according to claim 1,
A drainage control device, wherein the drainage means performs drainage operation at a water level within a predetermined range. 7. A drainage control device comprising a water storage tank for storing waste water, a waste water pump for draining the waste water from the water storage tank, and a pump control device for controlling the waste water pump, wherein the pump control device is a water storage device. A water level measuring means for measuring the water level of the tank, and a control signal for fetching the water level data from the water level measuring means, calculating a required drainage capacity necessary for draining a predetermined flow rate at the water level, and generating a required drainage capacity control signal. A drainage control device comprising: a generator and a pump variable controller that controls the drainage capacity of the wastewater pump based on the required drainage capacity control signal. 8. The drainage control device according to claim 7, wherein the control signal generation means fetches the water level data at predetermined time intervals to calculate a required drainage capacity. 9. The drainage control device according to claim 7, wherein the pump control device drains the sewage pump at a water level within a predetermined range.