JPS5920815A - Water level meter - Google Patents

Abstract

PURPOSE:To measure the level of a water surface without temperature correction, by forming the configuration of a float so that the up and down movement of the float due to temperature change is offset by the change of the part, which is formed between the water surface and a level measuring position, based on the thermal expansion of the part. CONSTITUTION:Level meters 10, which are arranged at two points are connected by a communicating pipe 12. A container 11 is filled with water. A float 14 is floated on the water surface. A difference L between the water level and the height of a level measuring position is read by a level measuring device 18 through an arm 15 of the float. The float 14 comprises a part 14a which is always immersed below the water surface, and a part 14b which is always protruded above the water surface. The configuration of a part 14c of the float 14, which is contacted with the water surface, is formed, so that the change in the density of the water based on the temperature change and the displacement of the float 14 with respect to the water surface due to the thermal expansion of the float 14 are offset by the thermal expansion of a part, whose length is L, between the water surface and the level measuring position. Thus the level of the water surface can be accurately measured without temperature compensation.

Description

[Detailed Description of the Invention] The xylophone is measured by the height of the water surface of the water that is poured into containers connected to each other by level fire communication pipes at two or more distant locations, and the height of the water surface. A float floating on the surface of the water and the movement of the float are converted into electrical signals using a differential transformer, etc., causing sweat. , Concerning water level gauges.

In general, when this type of water level meter is used in a place where the ambient temperature changes, it is important to note that the temperature of the water inside the container changes due to the density force 1 temperature, and that the water temperature is uneven due to the occurrence of natural convection. Because of this, the rising part (height) of the container should be made extremely low, and the arm should be extended upwards from the float.
While transmitting the movement of the float using the localization voice, it also corrects the water surface height due to changes in the density of the water, and the changes in the vertical movement of the float due to the thermal expansion of the arms, the thermal expansion 3d of the float, and changes in the density of the water. Conventionally, these supplementary iEs have been calculated and corrected individually. However, the correction is complicated, and errors in the respective Ω correction amounts accumulate, making it difficult to improve measurement accuracy.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and provide a water level meter that does not require temperature correction.

According to the present invention, the above object is achieved by the change in the density of water due to temperature IK and the vertical movement change with respect to the water surface caused by thermal expansion of the float, which causes thermal expansion of the portion formed between the water surface and the level % 11111 fixed position. IC so that they cancel each other out due to changes in
This is achieved by means of a ridge that forms the contact part of the float with the water surface.

Furthermore, in the present invention, the float, the arm of the float, and the level d11
1. If the arm of the constant device is made of the same material, the float's water TI
It is easy to determine the shape of the contact area with the container, the float, the arms of the float, and the level (the arms of the fixed equipment ffj are the same).
B11. (If the water is stored in a container, it will be easier to maintain the same temperature.Example of the sewage invention will be explained based on the drawings.First
The figure shows an embodiment of the present invention, and is a diagram of the main part of a water level meter that extends an arm above the float and transmits the movement of the float until it reaches the measuring point. In the Dowa, it consists of a rotary position f and a measuring device gJ, 18 which are made up of a water heater transformer and the like, and these are housed in a common case-shaped cover 13. It is a 19-piece thermometer. When measuring the levels 17a, 17b, and t, water level gauges 10 are placed at two locations on a common floor surface 20. Then, these water level meters 10 are connected to each other through a communication pipe 12, a container 11 is filled with water, and a float 1.
Install 111 localization M, 17a, 17b K.

As a result, the current of the float 14 is transmitted to the level measuring device 18 via the arm 15 of the float, and the water surface and level II'11 are
j The change in the height difference of the fixed part is level 1lllll fixed W,
18K is read and the level adjustment with 117aξ17b becomes possible in 7 rows 5.

FIG. 2 shows an elevated view of the floats 1 and 10 shown in FIG. 1.

The shape of the part 14a of the float 14 that sinks below the water surface and the part 14b that always protrudes from the water surface can be arbitrary.
For example, a weight 14d is provided at the bottom to keep the float in a steady state, and the shape is suitable for attaching the arm 15. The shape of the portion 14c of the float in contact with the water surface is configured as follows so that the thermal expansion of the portion of length L between the configuration m1 and the fixed position of level 611 exactly cancels out each other.

This will be explained below based on the formula. Float 14 and float @1
5 is made of the same material, heat 1) :ro, (T
+20) The specific gravity at °C is r, the total weight of the float (adding the weight of the float 14 and the arm 15, t) VW and -
Eel. Volume V of a float submerged in the water surface when the temperature is 20°C. is the buoyant force balance equation 7% (T + 20) When the volume of the float submerged below the water surface vT at 20°C is calculated as the volume (Vo + V)K at 20°C, It is expressed as t+β'r >, and if we consider the balance equation of buoyancy again, the following equation holds true for vTγ-W.

w −voγ. -γ (Vo+V) ・ (1-
βT)3 Therefore, compared to the case of 20°C, (T -4
-20) °c, the part of the float corresponding to ■ will be newly submerged under the water surface, and V is expressed as follows〇On the other hand, the relationship between the water surface and the fixed position of the level The part of length L between (
part of the float and the arms of the float) from 20℃ (=T+
20) βI, TO) Thermal expansion due to temperature change in °C.

If the height of the float corresponding to (■) above is set to exactly βLTK, the change in the submerged height of the float and the thermal expansion of the L portion will cancel each other out, and the water surface will always remain constant regardless of temperature changes. The correct value of high can be measured. That is, if the line of intersection of the float with the water surface at 20° C. is the base line 1), and the cross-sectional area of the float at a distance h SEβLT from there is A(h), the following equation holds true.

The surface fJIAITl is Atr+=-! −・”2 should be sufficient.

βI, clT - As an example, the shape 7 of the portion 14c of the float in contact with the water surface is determined based on the above subtraction formula. In order to make it easier to obtain a uniform temperature by reducing the heat capacity of the measurement part and by using a material with good thermal conductivity, what materials should be used for the float 14 and the arm 15? The weight of the whole float is 10 using aluminum with a W thickness! i+-, the height from the water surface to the measurement position L) 1000 pm, the specific gravity of water at 20°C i ro = 0.9982 g ~, the thermal expansion coefficient of aluminum β-2,303 No-' is 11 magnitude Accordingly, when the shape of the portion 14c of the float in contact with the water surface is determined, it becomes a value that is approximately missing.

(T+20)℃r (pha) A(mf) D (
h (-βI, Tflfi)20 0.9
98 59 9 030 0
．． 996 101 11 0.23
40 0.992 1B7 13
0.46511 0.988 170
．． 15 0.6960 0.983
200 16 0.9270 0.
978 230 17 1.15 From the above values, the shape of the portion 14c of the float which is in contact with the water surface is an inverted cone.

The water level meter of the present invention is based on the above-mentioned condition that the temperature of each part of the float and arm is equal to 5K, but by placing them in a common housing-like cover 13, a uniform temperature can be achieved. From the above, the cross-sectional area of the part of the float that comes into contact with the water surface is
By setting up the float so that the vertical movement of the float due to buoyancy is canceled out by the thermal expansion of the length and eye part between the water surface and the level measurement position, the float and its arms will remain stable regardless of temperature changes. Water surface height can be measured accurately without the need for temperature correction due to thermal expansion.

Figure 3 shows another embodiment of the invention, and is a diagram of the main part of water level control 1 which measures the movement of a float by taking out the downward KPA from the measurement position. In the figure, components K that are the same as those shown in FIG. 1 are the same reference numerals)! By adding 1-, the name of the station is omitted. This water level meter 30 has a float 31 with an upper arm 32, and has a horizontal position of 11.17a, +7
From b, the movement of the float is measured by the level measuring part fff 18, which has an arm 33 extended to the lower blade, and the position measuring part fit 18, which is made up of the differential transformer 7 and the paddle at the tip of the lower blade, measures the movement of the float.
A, 17b level adjustment method is used! For the case of the c method ((), the same 1 mK as shown in Fig. 1 can be obtained by using the float and l.

In other words, the contact of the float with the water surface is canceled out by changes in water density due to temperature and thermal expansion of the float - changes due to thermal expansion pressure of the part of the world and the level ωIJ The shape of the part? By deciding, the above-mentioned purpose can be achieved.

The present invention is a water level fi+ system in which a container connected by a communication pipe is filled with water as described above, a float is floated on the water surface, and the movement of the float is read. By shaping the float so that the vertical movement of the float relative to the water surface that occurs when the temperature changes due to temperature changes is canceled out by the thermal expansion of the portion formed between the water surface and the measurement position, It is possible to provide a water level meter that can accurately determine the water surface level lff1l regardless of the temperature without temperature correction.

[Brief explanation of the drawing]

1st. The figure shows an embodiment of the present invention, and is a configuration diagram of the main parts of a water level meter that extends the arm above the float and transmits the movement of the float to the measuring position. Figure 2 is a structural diagram of the float shown in Figure 1. Figure 3 is 'A-: Other embodiments of the invention (not shown): A configuration diagram of the main parts of a water level meter that measures the movement of a float by extending its arm downward from the measurement position. Water level meter, 11. ...container, 1
2...Communication pipe, 13...Casing-shaped grinder, 14, 31
... Float, 14c... Part of the float in contact with the water surface, 1
5.32... Arm of float, 16... Water surface, 33...
Arm of level measuring device. Ding 1 Diagram T2 Opening 13 Mouth

Claims (1)

[Claims]]) A water leveling system in which containers whose bottoms are connected to each other by a communicating pipe are filled with water, a float is placed on the water surface, and the level is determined by the movement of the float.・The change in the vertical movement of the water surface caused by the change in water density due to temperature and the thermal expansion of the float causes the I between the water surface and level +1111 orientation r.
II''
In the water level division described in Claims No. 2, the water surface and the level 611 are
A water level cap characterized in that the Ir11 VC formed portion with one fixed position is part of the float and the float is ll:ij. 3) Feature R'"In the water level cutting described in claim 1, the part formed between the water surface and the out-of-level measuring position is a part of the float, the arm of the float, and the level measuring device r. A water level meter characterized by having an arm. 4) At the water level described in the range of the special n'r request from the 1st m to the 3rd J peak, the float and the float σ) arm and level 1llll.
The arm of the device is made of the same material as the one bell meter. 5) The water level needle according to claim J, characterized in that the height of the container filled with water is relatively small. 6) At the water level fJt' according to claims 131 to 5, the container, the float, the arm of the float 9 and the arm of the leveling device are arranged within a common housing-like cover. Features a water level meter that is housed in