JPS62228117A - Liquid level detector - Google Patents

Abstract

PURPOSE:To continuously detect the change in the liquid level within a liquid tank with high accuracy, by sensing liquid pressure by a pressure-sensitive element equipped with a flow blocking means buffering a liquid stream. CONSTITUTION:A pressure-sensitive element 22 using a semiconductive strain resistor type sensor is arranged to an inner wall part of a liquid tank 6 at a position of a level H0 lower than a high water level H1 and the porous filter 23 of a flow blocking means buffering the liquid stream from a spigot 7 is provided to constitute a liquid level detection device 21. The liquid pressure corresponding to the level difference from the surface of a liquid to the arranged position is sensed by the pressure-sensitive element 22 and the continuous change in the liquid level is detected as the change in a resistance value to be transmitted to the level detection circuit of a hot water supply control unit 13 as an electric signal. The electric signal is converted to the liquid level corresponding to the resistance value of the pressure-sensitive element 22 on the basis of the conversion reference of a predetermined resistance value/liquid level by a converter through amplifier.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid level detection device suitable for installation in bathtubs, various liquid tanks, and the like.

[Prior Art] Conventionally, as a liquid level detection device for a bathtub, etc., a float that moves upward according to changes in the liquid level in the bathtub, a magnetic proximity switch fixedly placed at a predetermined level in the bathtub, and a float have been used. A type of magnet is used which is provided in the magnetic proximity switch to enable the magnetic proximity switch to turn on and off.

[Problems to be Solved by the Invention] However, the conventionally used liquid level detection device described above is only capable of detecting a liquid level that is the same as the set level of the m-air proximity switch. It was not possible to continuously detect changes in surface level.

In addition, as a conventional liquid level detection device,
A device using a pressure switch as described in Publication No. 595 has been proposed, but even this liquid level detection device using a pressure switch cannot detect only a certain level of liquid level corresponding to the set pressure of the pressure switch. It just makes it possible.

In addition, when detecting the liquid level in bathtubs, etc.

The hydraulic shock of the liquid flowing in from a faucet or the like with a strong force may reach the liquid level detection device, causing a malfunction of the liquid level detection device, such as a pressure switch turning on and off repeatedly. It is necessary to prevent stable operation from occurring.

An object of the present invention is to enable continuous and highly accurate detection of changes in liquid level using a simple structure.

[Means for Solving the Problems] The liquid level detection device according to the present invention includes a pressure-sensitive element in a portion of the liquid tank that communicates with the liquid storage part, and a liquid level detection device on the side of the liquid storage part of the pressure-sensitive element. A flow blocking means is provided to transmit the liquid pressure of the liquid to the pressure-sensitive element in a state where the flow is buffered, and the liquid level in the liquid tank is detected by the liquid pressure sensed by the pressure-sensitive element. be.

[Function] According to the present invention, the liquid level detection device is set at a predetermined level in the portion of the liquid tank that communicates with the liquid storage section, buffers the liquid flow in the liquid tank by the flow blocking means, and buffers the liquid flow in the liquid tank by the flow blocking means. The pressure-sensitive element applies the liquid pressure of the converted liquid to the pressure-sensitive element.The pressure-sensitive element senses the liquid according to the level difference (hydraulic head H) from the liquid level in the liquid tank to the set position of the pressure-sensitive element. Continuously detecting all changes in the surface level becomes the t1 function.

In addition, the flow blocking means has the ability to prevent a strong liquid flow in the liquid tank from directly acting on the pressure-sensitive element, so that a hydraulic shock is not exerted on the pressure-sensitive element, and the pressure-sensitive element can be detected. It becomes possible to stabilize the condition and improve the detection accuracy.

C Embodiment] FIG. 1 is a schematic diagram showing an embodiment of the present invention, FIG. 2 is a control block diagram of the embodiment, FIG. 3 is a sectional view showing a liquid level detection device of the embodiment, and FIG. FIG. 4 is a block diagram showing the liquid level detection circuit of the same embodiment.

In FIG. 1, reference numeral 1 denotes a water heater, in which a cooling supply pipe (water pipe) 2 is connected to a water supply port, and a hot water supply pipe 9 is connected to a hot water supply port.
A is connected. It is assumed that this hot water supply device 1 delivers a fixed amount of hot water (temperature To) per unit time during steady state. The hot water supply pipe 9A is connected to the hot water supply pipe 3 via the mixing valve 4, and the hot water supply v3 extends to the serpentine lower portion of the bathtub 6 via the electromagnetic valve 5. Further, a cold water supply pipe (water pipe) 9B that bypasses the water heater ll is connected to the mixing valve 4. The bathtub 6 is provided with a water faucet 8 in the form of a solenoid valve with an open/close confirmation switch.

Reference numeral 10 denotes an operation panel, which has a hot water supply push button switch 11 and a drain push button switch 12.

Reference numeral 13 denotes a hot water supply control device, which includes a hot water supply amount control section 14 and a faucet control section 15 . The hot water supply amount control unit 14 receives an operation signal from the hot water supply push button switch 11 and controls the opening and closing of the solenoid valve 5 .
In response to the operation signal, the faucet 8 is turned off.

Reference numeral 16 denotes a setting board, which has a temperature setting device 17 and a level setting device 18.

On the other hand, a temperature detection device 19 is attached to the hot water supply pipe 3 closer to the bathtub 6 than the electromagnetic valve 5. Further, the hot water supply control device 13 is provided with a temperature control section 20 . The fjA degree control section 20 takes in the set temperature TO set by the temperature setting device 17 and the output T of the temperature detection device 19, and generates a temperature control signal when there is a difference in temperature. The mixing ratio control signal X is given to the mixing valve 4 to obtain the desired hot water supply temperature To.

Furthermore, there is a liquid level detection device on the inner wall of the bathtub 6! ! 12
1 is installed. The liquid level detection device 21 is installed at a level Ho, which is lower than the full water level H1. This liquid level detection device 21 is provided with a pressure sensitive element 22 in a recess 6B that communicates with the liquid storage part 6A of the two bathtubs 6, and a water flow flowing through a lower snake on the side of the pressure sensitive element 22 facing the liquid storage part 6A. A porous filter 23 is provided as a flow blocking means to transmit the water pressure of the water flow to the pressure sensitive element 22 side in a buffered state, and the liquid in the bathtub 6 is The surface level is the detection capability. Liquid level detection device! 21 uses, for example, a semiconductor strain resistance type sensor as the pressure sensitive element 22, and measures continuous changes in the level difference (water head H) from the water surface to the installation position of the pressure sensitive element 22 of the water pressure acting on the pressure sensitive element 22. Detection a is defined as a resistance value change of the pressure sensitive element 22 based on the change.

The detection result of the liquid level detection device 21 is transmitted to a level detection circuit 24 provided in the hot water supply control device 13. The level detection circuit 24 is constructed as shown in FIG. That is, an electric signal corresponding to the change in the resistance value of the pressure sensitive element 22 constituting the liquid level detection device 21 is transmitted to the converter 26 via the amplifier 25. The converter 26 converts the liquid level corresponding to the resistance value of the pressure sensitive element 22 using the resistance value/liquid level relationship predetermined in the setting device 27 as a conversion standard, and converts the converted liquid level. The surface level is transmitted to the level output device 28.

That is, the pressure sensitive element 22 of the liquid level detection device i21 detects the level difference (
It senses the water pressure according to the water head (H) and continuously detects any changes in the liquid level. Also, a liquid level detection bag! !
21 prevents the strong water flow inside the bathtub 6 from directly acting on the pressure sensitive element 22 due to the presence of the porous filter 23. The detection state of the pressure element 22 is stabilized, and its detection accuracy is improved.

Note that the liquid level value output by the level detection circuit 24 is determined by the full water check section 2 provided in the hot water supply control device 13.
9, transmitted to the leak check section 30.

The full water check section 29 generates a full water signal F when the liquid level value output by the level detection circuit 24 reaches the full water level H1 set by the level setting device 18, and uses this full water signal F as the hot water supply amount. The information is transmitted to the control unit 14. Water supply quantity system! [114 closes the solenoid valve 5 when receiving the full water signal F.

The leak check section 30 has a 1-year leak check section 30A and a post-filling leak check section 30B. monitors the rising speed of the valve, and outputs a leak detection signal A when the rising speed is lower than the standard speed. The post-filling leak check section 30B outputs a leak detection signal B when the output value of the level detection circuit 24, ie, the liquid level, decreases after filling with water. The leak detection signals A and B are transmitted to the hot water supply amount control section 14, and when the hot water supply amount control section 14 receives the leak detection signals A and B, the solenoid valve 5 is activated.
Close the valve.

The 0 display panel 31, which is a leather panel 31, is equipped with an indicator light 32, and when the hot water supply amount control section 14 is in hot water supply operation, the indicator light 32 flickers slowly, and the water filling check section 2
9 outputs the full water signal F, the indicator light 32 is turned on stationary, and the leak check section 30 outputs the leak detection signal 30A, 30.
When outputting B, the indicator lamp 32 is turned on with a rapid flicker.

According to the above embodiment, the pressure sensitive element 22 and the porous filter 2
By using the liquid level detection device 21 equipped with 3, as described above, it becomes possible to continuously and highly accurately detect changes in the liquid level with a simple structure.

In addition, the porous filter 2 of the liquid level detection device 121
3, when cleaning the inner wall surface of the bathtub 6, the pressure sensitive element 22 is maintained. In addition, the liquid level detection bag 21
The porous filter 23 21 prevents dirt from entering the recess 6B in which the pressure sensitive element 23 is installed.

FIG. 5 is a cross-sectional view of a modified example of the liquid level detection device of the present invention. This liquid level detection device 40 includes a pressure sensing element 41 in a recess 6B communicating with the liquid storage part 6A of the bathtub 6, and covers the side of the pressure sensing element 41 facing the liquid storage part 6A with a cover 42. A liquid inlet 43 is provided in the door portion, and an F outlet 44 is provided in the upper part of the cover 42.

It should be noted that the present invention is also applicable to a telecontrol device in which the operation panel is a telephone.

Further, the present invention is widely applicable to, for example, liquid level detection devices in chemical plants.

C Effects of the Invention J As described above, the liquid level detection device according to the present invention is provided with a pressure sensitive element in the part communicating with the liquid storage part of the liquid tank, and also has a pressure sensitive element on the liquid storage part side of the pressure sensitive element. Providing a fast flow means for transmitting the liquid pressure of the liquid to the pressure sensitive element side while buffering the flow,
The liquid level in the liquid tank is detected by the liquid pressure sensed by a pressure sensitive element. Therefore, with a simple structure, it is possible to detect changes in the liquid level continuously and with high precision.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an embodiment of the present invention, Fig. 2 is a control block diagram of the embodiment, Fig. 3 is a sectional view of the liquid level detection device of the embodiment, and Fig. 4 is a schematic diagram showing an embodiment of the present invention. FIG. 5 is a block diagram showing the liquid level detection circuit of the same embodiment, and a sectional view showing a modification of the present invention. 6... Bathtub, 8A... Liquid storage part, 6B... Recessed part,
21.40...Liquid level detection device, 22.41...
・Pressure sensitive element, 23...porous filter [fast flow means]
, 42...Cover [fast flow means]. Patent applicant Representative of Sekisui Chemical Co., Ltd. Tomb 1) Kei No. 3 Figure 4 Figure 4, □, □o□, , 2

Claims (1)

[Claims] (1) A pressure-sensitive element is provided in the part of the liquid tank that communicates with the liquid storage part, and the liquid pressure of the liquid is applied to the liquid storage part side of the pressure-sensitive element in a state where the liquid flow is buffered. A liquid level detection device that detects the liquid level in a liquid tank by the liquid pressure detected by a pressure-sensitive element.