JPS60111117A - Water level detecting element - Google Patents

Abstract

PURPOSE:To detect a water level with few mulfunction of water level detection and reduced noises by providing a cover having a flowing out and in hole for water, air and water vapor and covering at least a detecting part of a water level detecting element. CONSTITUTION:The uncovered water level detecting element 3 using alumina porcelain and a thick film platinum-alumina as an insulator 1 and an electrode 2 respectively is covered with a cover 6 made of glass reinforced nylon having at the side surface a slit extending to up-and-down direction and serving as a water flowing-out hole 4 and also as a flowing out and in hole 5 for air and water vapor. Thus, the water level detecting element is obtained. By covering at least the detecting part with the cover having the flowing out and in hole for water, air and water vapor in such a way, the water level can be detected with a few mulfunction of the water level detection or decreased noises, even at the time of boiling and violent surface vibration of water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water level detection element for detecting the water level of various conductive aqueous solutions, which causes less malfunction or noise in water level detection even during boiling or when water surface vibrations are severe.

Conventionally, it has an electrode and an insulating material that holds the electrode,
Conduction-type water level detection elements that detect the water level based on the presence or absence of electrical continuity between such electrodes and the water surface are widely known.
There are known devices that hold a ferrite electrode or a stainless steel electrode and use a container containing a liquid whose water level is to be detected as a counter electrode.

However, this type of element has many malfunctions or noises in detecting the water level during boiling or when the water surface vibrates violently, and cannot accurately detect the water level. Moreover, it cannot be used if the liquid storage container is made of an insulating material such as plastic, and even if the container is made of conductive material,
If the inner surface of the container corrodes or oxidizes, it will be affected and cannot be used stably for a long period of time.

The present invention was made to solve this drawback.
The purpose of this system is to detect water level with high accuracy, with less malfunction or noise in water level detection, even during boiling or when the water surface vibrates violently.

A second object of the present invention is to confine the detection current within the cover by making at least a portion of the cover a conductor that also serves as a counter electrode, thereby detecting the water level without being affected by the conductivity of the container.

The present invention includes an electrode and an insulating material holding the electrode,
The water level detection element detects the water level based on the presence or absence of conduction due to contact between the electrode and the water surface, and the water level detection element includes a cover having inflow and outflow holes for water, air and water vapor, and covering at least a detection part of the water level detection element. This is a water level detection element.

By the way, the shape of the cover in the present invention is not limited as long as it covers at least the detection part of the water level detection element, but if the detection part is plate-shaped, rod-shaped, etc., the cover covers the side surface of the detection part and the inner surface of the cover. A cylindrical shape is preferable because the distance between the two is uniform. The distance between the side surface of the detection part and the inner surface of the cover is preferably one square or more so that a film of water is not formed. In addition, if the cover has a bottom surface, for the same reason, the distance between the tip of the detection unit and the inside bottom surface of the cover should be at least 1 mm if the cover is an insulator, and at least 2 mm if the cover is a conductor.
It is preferably 2, and more preferably 10 or less in order to enhance the wave-proofing effect of the cover.

Moreover, water provided in the cover in the present invention.

The air and water vapor inflow and outflow holes are for water inflow and outflow and air and water vapor inflow and outflow. The water inflow and outflow holes prevent the inflow of water due to local elevation of the water surface caused by water droplets and air bubbles, and also restrict the flow rate against sudden changes in water level, with the cover acting as a kind of integral circuit. , reducing the noise of the detection signal.

Furthermore, the water inflow and outflow holes in the present invention have a structure that does not impair water level detection responsiveness, prevents the influence of local upheaval of the water surface due to water droplets and air bubbles, and is effective in reducing noise in the detection signal. Preferably, it has a slit structure as shown in Fig. 1, which also serves as an inflow/outflow hole for air and water vapor, or a slit structure with, for example, four slits on the end face of the circular pipe as shown in Figs. 2(a) and (b). A structure in which a cut is made and the four end pieces are folded sequentially or alternately from the cut, or a structure in which the direction of water flow is changed, such as a double ME/7 structure as shown in FIG. 3, is preferable. Further, these small holes, slits, etc. are preferably arranged on the side surface of the cover.

Furthermore, since the water inflow and outflow holes become a source of bubbles within the cover in boiling water, it is preferable that the surface has a smooth surface shape without any sharp edges or edges.

If the air and water vapor inflow and outflow holes provided in the cover of the present invention also serve as water inflow and outflow holes, it is preferable that they be placed farther from the water surface than the detection part, especially when the cover is in boiling water. In order to prevent the water surface from being pushed down by an increase in atmospheric pressure, it is preferable that the size of the tank is large enough to allow water vapor or air to flow out.

The cover of the present invention needs to have the necessary strength as a protective tube for a conductive water level detection element, and its material is preferably metal, ceramics, plasticsock, etc. It is more preferable to use it also as a counter electrode because it can be used without being affected by the conductivity of the container containing the liquid whose water level is to be measured. Further, the voltage applied to the water level detection element of the present invention is not limited to direct current, but may be alternating current or pulse voltage.

Hereinafter, the illustrated embodiments of the present invention will be described in detail.

First, as shown in FIG. 1, a water level detecting element 3 without a cover using alumina porcelain as the insulating material 1 and thick film platinum-alumina as the electrode 2 is connected to the inlet/outlet hole 4 for water and the outlet for air and water vapor. It was covered with a cover 6 made of glass-reinforced nylon having a vertically extending slit on the side surface which also served as an inlet 5 to obtain a water level detection element of the present invention. Water level detection element 3
The distance between the side surface of the detection section and the inner surface of the cover 6 was 2.5-, and the distance between the tip of the detection section and the bottom surface of the cover was 51i.

In addition, as shown in Fig. 2 <a> and (b), four notches are made in the end surface of the circular tube for the water level detection element 3 without a cover, and the four end pieces are sequentially inserted from the notches. A water level detecting element of the present invention was obtained by covering with a stainless steel cover 6 having a folded tip.

Further, as shown in FIG. 4, a water level detection element without a cover using alumina porcelain as the insulating material 1 and thick film platinum-alumina as the electrode 2 was wired as shown in FIG. 5(a). The voltage of the DC power supply 9 is 5V, the voltage dividing resistor 10a,
The values of 10b were 60Ω and LMΩ, respectively, and the area of the electrode 1 shown in FIG. 4 was 61,112.

Using the water level detection element shown in Fig. 4 without this cover, 10
The results of detecting the water level of boiling water at 0°C are shown in Figure 6 (
Shown in a) to FIG. 6(g).

In Figure 6 (al) to Figure 6 fgl, the vertical axis is the output voltage and the horizontal axis is time. FIGS. 6(b) to 6(gl) show the output signals when the water level detection element is successively separated from the reference position by 5 mm in the direction perpendicular to the water surface.

Further, FIG. 3 shows the water level detection section of the element shown in FIG. 4.

The water level detection elements of the present invention each covered with a stainless steel cover having the structure shown in FIGS. 7 and 8 are shown in FIG. 5(b).
Connect the cover as a counter electrode as shown in 10
The results of water level detection of boiling water at 0°C are shown below.

In other words, the water inflow and outflow holes 4 in Fig. 3 are doubled.
It is a 0 mesh stainless steel mesh, and the distance between the tip of the detection part and the inner stainless steel mesh surface that is the bottom of the cover is 8 mm. The water inflow/outflow hole 4 in Fig. 7 is a circular hole with a diameter of 8 mm.
The distance between the tip of the detector and the bottom of the cover is l, Q+u.

In addition, the water inflow and outflow holes 4 in Fig. 8 are circular holes 8 with a diameter of 1.1 fins.
The sensors are arranged near the bottom of the cover, and the distance between the tip of the detection unit and the bottom of the cover is 6 distances.

The results of detecting the water level of boiling water at I 00 "c using the water level detecting elements of FIGS. 3, 7, and 8 covered with covers are shown in FIG. 9 (al to FIG. 9). fd
+ and shown in FIGS. 10(a) to 10(f) and FIGS. 11(a) to 11tc+.

In each case, the vertical axis is the output voltage, and the horizontal axis is time. Figures 9(a), 10fa) and 11(al)
The output signals at the reference position where the tip of the detection unit is 0 to 2 degrees below the water surface are shown, and
Figure 0 (bl to Figure 10 (out) and Figure 11 (b) to Figure 11 (C1) show the output signals when the water level detection element is sequentially separated from the reference position by 5 squares in the vertical direction to the water surface. It shows.

Detection by a water level detection element without a cover is shown in Figure 6 (a).
As shown in GL, the noise reach distance is 30'+n or more from the reference position, the width of the water level uncertainty area is approximately 101 m, and the underwater noise level is 0.5 ■, but it is covered with a cover. The three types of water level detection elements of the present invention are
As seen in Figures (al to d), Figures 10 (a) to fl, and Figures 11 (a) to C), the noise reach distances are less than 15 and 25 from the reference position, respectively. and less than 10 fins, the width of the water level uncertainty region is less than about 5 fins, and the underwater noise level is reduced to 0.2 V, 0.3 V, and 0.1 ■, respectively;
It can be seen that the system has been improved, has less noise, and has high water level detection accuracy.

As is clear from the above description, the water level detection element of the present invention covers at least the detection part with a cover having inflow and outflow holes for water, air, and water vapor, so that the water level detection element can be used even during boiling or when water surface vibration is severe. It is possible to perform water level detection with less detection malfunction and noise, and is particularly useful for detecting the water level of boilers and the water level of cooling water in various devices such as engines, and can also be detected without being affected by containers. Therefore, the present invention is an extremely advantageous water level sensing element for industry.

[Brief explanation of drawings]

FIGS. 1, 3, 7 and 8 are half-sectional views of specific examples of the water level detection element of the present invention, and FIGS. 2(a) and 2(b) are respectively half-sectional views of water level detection elements according to the present invention. A perspective view and partially cutaway front view of the bottom part of a specific example of the element, FIG. 4 is an external view of a specific example of a water level detection element without a cover, and FIG. 5(a) is a water level detection element without a cover. FIG. 5(b) is an explanatory diagram showing a specific example of the water level detection circuit used in the present invention. FIG. 6(al) to 6(g) are explanatory diagrams showing the output signals of the water level detection element without a cover, respectively, and FIG. 9(al to 9(dl), and FIG. 10 1a) to 1θ diagram (f) and FIGS. 11 (a) to 11 tc+ are explanatory diagrams showing output signals of the water level detection element of the present invention, each of which is provided with a cover that covers at least the detection part. 1; Insulating material 2 : Electrode 3; Water level detection element without cover 4: Water inflow/outflow hole 5: Air and water vapor inflow/outflow hole 6: Cover 7: Detection section 8: Signal terminal 9: DC power supply 10a, 10b: Voltage dividing resistor 11; Water surface 12; water level detection element of the present invention Fig. 4 Fig. 7 Fig. 8 Fig. 6 Fig. 9 Fig. 10 (a) (b) (C) (d) (e) (f) 1 (a) 1 Time (min) (b) (c)

Claims (1)

[Scope of Claims] (1) A water level detection element that has an electrode and an insulating material that holds the electrode, and detects the water level based on the presence or absence of continuity due to contact between the electrode and the water surface. A water level detection element characterized by having an inflow/outflow hole and a cover that covers at least a detection part of the water level detection element. (2) The water level detection element according to claim 1, wherein the cover is cylindrical. (3) The water level detection element according to claim 1, wherein the cylindrical cover has inflow and outflow holes for water, air, and water vapor only on the side surface. The water level detection element according to claim 2. (4) The water level detection element according to claim 1, 2, or 3, wherein at least a part of the cover is a conductor and serves as a counter electrode.