JPH04171506A - Water level controller - Google Patents

Abstract

PURPOSE:To keep a constant water level under stable control despite a small change of the water level by setting the opening amount of an inflow valve so as to be inversely proportional to the water level when the water level of a distributing reservoir approximates to a target level and controlling the opening amount of the inflow valve based on the difference between the set valve opening amount and the present opening amount. CONSTITUTION:An inflow valve 4 is provided together with a water level/valve opening amount setting means 7, a valve opening amount comparison means 8, and an inflow valve opening amount control means 9. When the water level signal received from a water level indicator 2 is inputted to the means 7, an inflow level opening amount is decided in response to the water level based on the prescribed control characteristic. That is, a constant inflow valve opening amount where the inflow exceeds the maximum outflow is kept until the water level approximates a target level. When the water level exceeds the target level, the inflow valve opening amount is set at a level inversely proportional to a level change set optionally. Then the valve opening amount is controlled based on the difference between the decided opening amount and the present one. Thus the water level is stably controlled despite a small change of the water level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a water level control device for controlling the water level of a water supply tank or reservoir to a constant level, for example.

[Prior art] This type of conventional water level control device detects the water level of a water distribution reservoir with a water level meter, compares the detected output with a set output corresponding to a target water level, and calculates the level based on the comparison difference. It was configured to directly control the inflow valve on the water inflow side of the water distribution reservoir to keep the water level constant.

[Problem to be Solved by the Invention 1] By the way, the water level change in the water distribution reservoir is determined from the relationship between the capacity of the reservoir, the amount of water flowing into the pond, and the amount of water flowing out from the pond. Depending on the changes in inflow and outflow compared to the area, the change in water level may become small.

However, in the case of a configuration in which water level control is performed by an inflow valve with only changes in water level as the control object as in the above-mentioned conventional configuration, when the change in water level becomes small, the inflow valve repeats full opening or closing in order to approach the target water level. Simple ON@OFF control tends to cause so-called hunting phenomenon,
There was a problem in that it was difficult to perform stable water level control.

The present invention has been made in view of the above circumstances, and provides a water level control device that can accurately control the inlet valve opening according to subtle changes in water level and stably control the water level near the target water level. The purpose is to provide

[Means for Solving the Problems] In order to achieve the above object, a water level control device according to the present invention includes an inflow valve provided on the water inflow side of a water distribution reservoir, and a water level gauge that detects the water level of the water distribution reservoir. In response to a water level signal from water level/valve opening setting means that has control characteristics that can be arbitrarily set; and a valve opening comparison that compares the inflow valve opening set by the water level/valve opening setting means with the current inflow valve opening. and an inflow valve opening/closing control means for adjusting the opening of the inflow valve based on the comparison difference from the valve opening comparing means.

[Function] According to the above configuration, when the water level signal from the water level meter is input to the water level/valve opening setting means, the water level/valve opening setting means performs the above operations based on predetermined control characteristics. Determine the opening degree of the inlet valve according to the water level. In other words, the inflow valve opening is set at a constant rate so that the inflow exceeds the maximum outflow until the water level reaches around the target water level, and when the water level reaches around the target water level or higher, the inflow valve opens at an arbitrarily set inverse proportion to the change in water level. The opening degree of the inflow valve is determined based on the comparison difference between the determined valve opening degree and the current valve opening degree. As a result, stable water level control is possible even when changes in water level are small.

[Example] Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a configuration diagram showing a water level control device according to an embodiment of the present invention.

In the figure, 1 is a water distribution reservoir, 2 is a water level gauge that detects the water level of water 3 in the water distribution reservoir 1, and 4 is an inflow valve provided on the water inflow side of the water distribution reservoir 1. This inflow valve 4 is provided with a multi-hole variable orifice valve.

7 is a water level/valve opening setting means to which the water level signal from the water level gauge 1 is applied; Until now, a control characteristic has been added that allows the valve opening to be set such that the inflow exceeds the maximum outflow, and when the water level is above the target water level, the valve opening can be arbitrarily set in inverse proportion to the water level. There is.

8 is a valve opening comparison circuit for comparing the valve opening based on the water level output from the water level/valve opening setting means 7 with the current valve opening of the inflow valve 4; 9 is the valve opening comparison circuit 8; It is an inflow valve opening/closing control means for controlling the valve opening of the inflow valve 4 according to the comparative difference output from the inflow valve 4, and constitutes the controller 10 together with the water level/valve opening setting means 7 and the valve opening comparison circuit 8. ing.

Next, the operation of the above configuration will be explained.

Water 3 from the outside flows into the water distribution reservoir 1 at an inflow amount according to the current opening degree of the inflow valve 4, and a water amount according to the demand flows out from the water distribution reservoir 1. The water level of the water distribution reservoir I is detected by a water level meter 2, and the detected water level value at that time is inputted to the water level Φ valve opening degree setting means 7 as a water level signal.

For example, if the amount of water in distribution reservoir l is increasing,
Until the water level of distribution reservoir 1 reaches around the target water level, the water level and
According to the pre-region a of the control characteristic in the valve opening degree setting means 7, the inflow amount is set to a constant inflow valve opening degree exceeding the maximum outflow amount, and the valve opening degree output is sent from the water level/valve opening degree setting means 7. . Furthermore, when the water level in the water distribution reservoir 1 exceeds the vicinity of the target water level, the valve opening is inversely proportional to the water level, that is, the valve opening is reduced in accordance with the latter part of the control characteristic in the water level/valve opening setting means 7. The water level/valve opening setting means 7 then outputs the valve opening.

The valve opening output from the water level/valve opening setting means 7 and the current valve opening output from the inflow valve 4 are compared in the valve opening comparison circuit 8, and according to the comparison difference, the inflow valve opening/closing control circuit 9 controls the opening degree of the inflow valve 4. Therefore, even if the change in water level is small due to a change in the amount of outflow, for example, the opening degree of the inflow valve 4 is finely controlled according to the water level, and the water level in the water distribution reservoir 1 is maintained without causing the hunting phenomenon. It will be kept constant.

In this embodiment, since the inflow valve 4 is provided with a multi-hole variable orifice valve, if there is no large pressure fluctuation on the primary side of the inflow valve 4, the inflow amount can be determined from the opening degree of the inflow valve. water level control can be carried out smoothly.

[Effects of the Invention] As described above, according to the present invention, 1. When the water level in the distribution reservoir reaches or exceeds the target water level, the inflow valve opening is set to be inversely proportional to the water level, and the inflow valve opening is controlled based on the difference between the valve opening setting and the current valve opening. Therefore, even if the water level changes are small, the water level can be kept constant under stable control.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a water level control device according to an embodiment of the present invention. l...Water reservoir, 2...Water level gauge, 3...Water, 4...
- Inflow valve, 7...Water level/valve opening setting means, 8...Valve opening comparison circuit, 9...Inflow valve opening/closing control circuit. Patent applicant Kubota Co., Ltd. agent
Patent attorney Takashi Suzue - (1 other person)

Claims (1)

[Claims] 1. In response to a water level signal from an inflow valve provided on the water inflow side of the water distribution reservoir and a water level meter that detects the water level of the water distribution reservoir, the inflow is stopped until the water level reaches around the target water level. A water level/valve opening setting means having a control characteristic that allows the inflow valve opening to be set at a constant value that exceeds the maximum outflow, and when the water level exceeds the target water level, to arbitrarily set the inflow valve opening to be inversely proportional to the water level change. , a valve opening comparison means for comparing the inflow valve opening set by the water level/valve opening setting means with the current inflow valve opening, and a valve opening comparison means for comparing the inflow valve opening set by the water level/valve opening setting means; A water level control device characterized by comprising an inflow valve opening/closing control circuit that adjusts the degree of opening.