JPS598021A - Water level controller - Google Patents

Abstract

PURPOSE:To ensure smooth automatic control for a water level controller for pumping well, by switching between the unit number control system and the revolving number control system with the pump in response to the change of the water inflow. CONSTITUTION:A fixed revolving number signal generator 21 and a unit number control circuit 31 are newly provided. Then switching is carried out between these generator 21 and the control 31 in case the water inflow is extremely small. Therefore it is always possible to exercise automatic control smoothly and stably regardless of the change of the water inflow.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water level control device which drains inflowing filtrate fluid by means of a pump and has control means χ for keeping the water level on the suction side of the pump constant.

Conventionally, for example, in a pump well that uses a pump to drain fluid that flows into a drainage pump station, in order to maintain a constant water level in the pump well, control is performed by increasing or decreasing the number of pumps in operation and by controlling the rotation speed of the pump. It should be done in combination. Generally, in such conventional drainage pump stations, as shown in Figure 1, the water level of the pump well into which raw water flows from the inflow pipe l is measured by a water level gauge, such as a float type water level gauge, and the pump Lead wire 5V as well water level signal
PID/next adjustment measurement/TL is input from c. This PI
In the D/order control gauge 1, the pump well water level signal is adjusted and controlled together with the pump well target water level set value input from the lead MA, and the PTDj order control gauge λ is sent as the required total pump displacement signal via the lead line. and number control circuit/3
It should be output to . In this PID/secondary controller 72, the required total pump displacement signal from the PID/secondary controller 1 and the pump rotation sent from the pump rotation speed control device/f of the pump 3 via the lead wire 9 are used. The number is adjusted and controlled and output as a pump rotational speed manipulated variable to the pump rotational speed control device/lI via the lead wire g to determine the pump 30 rotational speed. On the other hand, the number control circuit/3 determines the required number of pumps 3 based on the required pump total displacement signal from the PID/next adjustment/monitor/, and outputs a start/stop signal for the pumps 3 to the pump 3 via the lead wire 10. do. In this way, the water level of the bong well is maintained at the Mesakaki water level setting value by controlling the number of 30 pumps and controlling the rotation speed.

Conventional water level control devices for pump wells configured in this manner generally keep the water level in the pump well constant;
When the amount of inflow water is extremely small, that is, when the target value is below the control range of the pump flow rate or rotation speed,
Rotational speed control using PID control became impossible, and the entire control system malfunctioned, with the unit controller repeatedly outputting pump start/stop signals, and as a result, manual operation was required at the operator's discretion. There are drawbacks such as the fact that automated equipment is of no use.

Therefore, an object of the present invention is to provide a new constant rotation speed signal generator and a number control circuit in order to eliminate the drawbacks of the conventional device, and to reduce the amount of inflow water to an extremely high level that cannot be controlled with the conventional device. It is an object of the present invention to provide a water level control '11 device which can always smoothly control the water level of a pump well by switching to the constant rotation speed signal generator and the number control circuit when the number of pumps is low.

According to this invention, the water level control device performs control by increasing or decreasing the number of operating pumps and control by the rotation speed of the pump in order to maintain a constant water level of the pump whose water level changes depending on the inflowing fluid. One type of combination is provided, and these combinations are switched and used depending on the amount of water flowing into the pump 1.

The features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings.

FIG. VC shows an embodiment in which a water level control device according to the present invention is applied to a drainage pump station, and the same parts as in FIG. 1 described above are given the same reference numerals. As shown in FIG. 2, the water level control device of the present invention, like the conventional control system, has a pump well into which water enters from the inflow pipe l.
A PID primary controller whose water level is measured by a water level meter and inputted as a pump well water level signal, a PID primary regulator connected to this PID, and a number control circuit 13. , a pump rotation speed control device connected to the PID secondary controller/intelligence controller, a number control circuit/3, and a pump 3 for pump well drainage connected to the pump rotation speed control device II. In addition, a constant rotation speed signal generator 21 and a number control circuit 31 are newly provided. In cases where the amount of water flowing into the inflow pipe/cutter is extremely small, which is poorly controlled with conventional equipment, when controlling the pump 30 rotation speed, the output is applied via the lead wire from the PID and primary controller 12. Bot 1 rotation speed operation amount is lead wire II/
The output from the constant rotation speed signal generating circuit is switched by the loop switching signal, and the output from the lead wire λ2. The rotation speed of the pump 3 is fixed by acting on the pump rotation speed control device/g via the pump 3. On the other hand, in controlling the number of operating pumps 3, the number control circuit 13 uses a system that determines the required number of pumps to be operated from the total amount of water required from the PID/next adjustment/detector.
The output of the pump operation/stop signal is switched by the switching signal from the lead wire Goo, which is applied via the separately determined pump well target water level set value from the lead wire 3θ and the lead wire S from the water level gauge. A number control circuit 31 that determines the number of pumps 3 based on the t'L pump well water level signal.
The output of lead #! 3s,,acts on pump 3 via y3. By doing this, the water level in the bong well is kept constant by the water level from the lead 830. For example, if the pump 3 is a stand-alone pump, as shown in FIG. That is, the second pump starts pump well water level AI
and the first pump stop bong well water level A'l. Furthermore, if the switching signal from the lead wire II/ is reversed, the control returns to the same as in the conventional control system. Regarding this embodiment, the switching signal from lead βψ&/ is manually switched at the operator's discretion;
If the water condition from the inflow pipe can be measured, the switching point can be set in advance from this measurement value and the switching can be done, or if the water level from the inflow pipe cannot be directly measured, the pump well λ It is also possible to estimate the amount of inflow water based on changes in the water level and the amount of water discharged from the drain pipe of the pump 3, and to switch the method. In addition, the PID surrounded by the dashed line in Figure 2
/Next, 2 measuring meters//, /ko, number control circuit/3. The portion including the constant rotational speed signal generator j/ and the number control circuit 31 may be controlled by a single digital instrumentation control device, for example.

As described above, the water level control device for a pump valve of the present invention is configured to switch between the number control method and the rotation speed control method for the pumps according to changes in the amount of inflow water. Regardless of the situation, automatic control will always be performed smoothly and stably, and the work environment for operators will be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a conventional water level control device for a pump valve, FIG. FIG. 2 is a schematic explanatory diagram of an example of a water level control device. In the figure, l...
Inflow pipe, installation...pump well, 3...pump, gφ, drainage'
fJ, s, t,, q. g, q, io, 2 pieces, 23. '30, 32. ．． 3,
1... Lead wire, //... PID/next controller weight 7.2.
ΦPID,! Next controller, /,? I 3/-One unit control circuit, /4'・Fist pump rotation speed control a device 1.2/...
Constant pump rotation speed signal generator, 4'/... switching signal, S
/... f41 pump operating range, S2... 1st co-pump operating range, AI... 2nd pump starting pump well water level, 62...
＠ll Song moving pump well water level, 63...1st pump stopped pump well water level, 63·O 1st pump stopped pump well water level. In addition, the same reference numerals in each figure indicate the same or corresponding parts; 1i-N. Agent Shin Kuzuno - Figure 1

Claims (1)

[Claims] +11 In a water level control device that controls a pump to maintain a constant water level in a pump well whose water level changes depending on the inflow of water, control by increasing or decreasing the number of operating pumps and control by the rotation speed of the pump. A water level divider 1 device characterized in that two types of combinations are provided, and these combinations are switched and used depending on the amount of fluid flowing in. (2) In order to control the pump so as to keep the water level in the pump well constant, a PID/next control meter 1 that is connected to a water level gauge and into which the pump well target water level setting value is input.
Water level control 7+111 device 'I' equipped with a PID controller and unit number control circuit, a PID controller and a bong rotational speed control device. At t, a constant pump rotation speed signal generator is connected to the pump rotation speed tlj control device e in a switchable manner by a switching signal to the PID and secondary controller, and a constant pump rotation speed signal generator is connected to the water level gauge and outputs the pump well target water level. The water level control according to claim 7, further comprising a pump number control circuit into which a set value is input and which is switchably connected to the pump by the switching signal to the number control circuit.