JP2008232669A - Liquid level detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid level detector having a simple constitution and excellent maintainability, and causing few wrong detections, in a tank wherein high-concentration or high-temperature chemical liquid is used such as a pickling tank, or in a tank wherein highly viscous liquid such as slaked lime liquid is used. <P>SOLUTION: This liquid level detector 10 is equipped with: a container 12 having a built-in switch 14 and a built-in diaphragm 20 having a striker 18 for the switch 14 attached to a lower position of the switch 14; a body air pipe 22 connected in the vertical direction of a lower part of the container 12; a bell type opening part 50 connected to the lower end of the body air pipe 22, and provided with, for example, a groove 50a on the inside surface; an initial pressure air pipe 24 connected to the side of the bell type opening part 50; and a vertically opening/closing type lid 52 mounted on an upper part of the bell type opening part 50 in the body air pipe 22. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid level detector, and is particularly suitable for use in a manufacturing field having a tank that circulates a high-concentration, high-temperature chemical solution such as a stainless steel pickling tank, a waste liquid treatment facility having a slaked lime tank, and the like. The present invention relates to a liquid level detector having a simple configuration, less erroneous detection, and excellent maintainability.

  In a tank filled with acid fume or a tank storing a high viscosity liquid charged with slaked lime or the like, as shown in FIG. 4 of Patent Document 1, as shown in FIG. And a proximity switch (hereinafter simply referred to as a switch) 14, and a container 12 having a diaphragm 20 with a striker 18 for the switch 14 in a position below the switch 14, and a vertical direction below the container 12. Pressure of the main pressure air 24 a supplied from the main pressure air pipe 24, the main body air pipe 22 for liquid level contact, the detection air pipe 28 connected to the upper side of the main body air pipe 22, and the main pressure air pipe 24. There is known a liquid level detector 10 provided with a pressure control valve 26 for reducing the pressure of the gas and supplying the air as a detection air 28a to the detection air supply pipe 28.

  In the liquid level detector 10, the lower end of the main body air pipe 22 is usually installed at a predetermined height above the pickling solution 42 of the pickling tank 40, for example. Therefore, when the liquid level rises, the lower end opening 22a of the main body air pipe 22 is closed, the pressure in the main body air pipe 22 increases, the diaphragm 20 is pushed up, and the switch 14 is operated by the striker 18. Therefore, the contact of the switch 14 is taken into the control device (not shown) via the switch wiring 16 and used as a liquid level detection signal.

  However, in a tank filled with acid vapor (referred to as acid fume), the acid fume naturally enters the inside of the main body air pipe 22 and adheres to the inner wall of the pipe and solidifies. The solid material grows, closes the lower end opening 22 a of the main body air pipe 22, and traps the detection air 28 a supplied from the detection air pipe 28 in the main body air pipe 22. As a result, the pressure inside the main body air pipe 22 increases, the diaphragm 20 is pushed up, the switch 14 is activated, and the liquid level detector 10 erroneously detects an increase in the liquid level when the liquid level does not contact the main body air pipe 22. It had the problem of end up.

  In order to solve this problem, the applicant, as shown in FIG. 1 of the above-mentioned Patent Document 1, has a configuration similar to that of the prior art shown in FIG. A throttle portion 22b is provided in the middle, and a lower end opening 22a is expanded in a trumpet shape. Further, a contact portion cleaning air pipe 30 is provided which communicates the upstream side of the pressure regulating valve 26 and the side surface immediately above the lower end of the main body air pipe 22. Propose that.

  According to the configuration of FIG. 4, a part of the original pressure air 24 a upstream of the pressure regulating valve 26 is supplied as the cleaning air 30 a to the upper part of the main body air pipe 22 immediately above the opening by the contact part cleaning air pipe 30. Thus, it is possible to prevent acid fume from entering the inside of the main body air pipe 22 and prevent erroneous detection of the liquid level detector 10 due to clogging of the main body air pipe 22.

JP 2003-222550 A (FIGS. 1 and 4)

  However, the prior art shown in FIG. 4 not only complicates the configuration of the air piping, but also makes it difficult to adjust the pressure of the detection air 28a. If the pressure of the original pressure air 24a is too high, a part of the cleaning air 30a passes through the throttle portion 22b and flows above the main body air pipe 22 to increase the pressure inside the main body air pipe 22, and the diaphragm 20 And the switch 14 malfunctions. On the contrary, if the pressure of the original pressure air 24a is low, the pressure of the cleaning air 30a becomes insufficient, and when the highly viscous liquid is scattered and attached to the lower end opening 22a of the main body air pipe 22, it cannot be removed sufficiently. There is a problem that maintenance work such as regular and frequent cleaning is required.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a liquid level detector having a simple configuration, less erroneous detection, and excellent maintainability.

  The present invention relates to a switch, a container in which a diaphragm with a switch striker is installed at a position below the switch, a main body air pipe vertically connected to a lower portion of the container, and the main body air pipe A bell-shaped opening connected to the lower end of the bell-shaped opening, a source pressure air pipe connected to the side of the bell-shaped opening, and a vertical opening / closing type attached to the upper part of the bell-shaped opening in the main body air pipe The above-mentioned problem is solved by a liquid level detector comprising a lid.

  A cleaning effect can be enhanced by providing a groove on the inner surface of the bell-shaped opening.

  According to the present invention, in a tank using a high-concentration, high-temperature chemical solution such as a pickling tank, a tank using a highly viscous liquid such as slaked lime liquid, etc., without increasing the number of air piping, It is possible to provide a liquid level detector with few false detections and excellent maintainability.

  Accordingly, it is possible to prevent the overflow of the liquid from the tank and to prevent the occurrence of equipment damage due to the overflow of the liquid (particularly acid) and the problem of environmental pollution.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the liquid level detector 10 of the present embodiment includes a switch 14 that is a proximity switch such as a microswitch, and a diaphragm 20 with a striker 18 for the switch 14 at a position below the switch 14. A built-in container 12, a main body air pipe 22 connected vertically to the lower part of the container 12, and a spiral groove 50 a, for example, is provided on the inner surface connected to the lower end of the main body air pipe 22. A bell-shaped opening 50, a source pressure air pipe 24 connected to the side of the bell-shaped opening 50, and a vertically openable / closable lid attached to the top of the bell-shaped opening 50 in the main body air pipe 22. 52.

  A spiral groove 50 a as illustrated in the bottom view of FIG. 2 is formed on the inner side surface of the bell-shaped opening 50.

  The diameter of the diaphragm 20 can be set to 90 ± 10 mmφ, for example, and the inner diameter of the main body air pipe 22 can be set to 25 to 35 mmφ, for example. Moreover, the pressure of the original pressure air 24a can be 0.05-0.1 Mpa, for example.

  The liquid level detector 10 is such that the lower end of the bell-shaped opening 50 at the lower end of the main body air pipe 22 is 50 to 100 mm above the liquid level of the pickling liquid 42 in the pickling tank 40 during normal operation. And the liquid level detector 10 installs in the position where the pickling liquid 42 does not overflow from the pickling tank 40 immediately after liquid level detection.

  In such a configuration, the original pressure air 24a supplied from the original pressure air pipe 24 is blown into the bell-shaped opening 50 and constantly flows below the bell-shaped opening 50 along the internal spiral groove 50a.・ Fume and dew such as acid and waste liquid adhering to the vicinity of the opening are washed away to the outside. Since the lid 52 is closed by its own weight until the liquid level of the pickling tank 40 rises and contacts the lower end of the liquid level detector 10, the source pressure air 24a supplied from the source pressure air pipe 24 is It flows downward along the groove 50 a in the bell-shaped opening 50 and does not enter the main body air pipe 22.

  On the other hand, when the level of the pickling solution 42 reaches the lower end of the level detector 10, the pressure in the bell-shaped opening 50 increases, and the upper lid 52 is opened. Accordingly, the original pressure air 24 a supplied from the original pressure air pipe 24 enters the main body air pipe 22 through the lid 52, increases the pressure in the main body air pipe 22, raises the diaphragm 20, and is switched by the striker 18. 14 operates to detect the liquid level.

  According to the present embodiment, no malfunction occurred and the maintenance work was reduced by 50% compared to the conventional liquid level detector.

  In the present embodiment, since the spiral groove 50a is formed on the inner surface of the bell-shaped opening 50, the inner surface of the bell-shaped opening 50 is cleaned evenly. Note that the shape of the groove is not limited to a spiral, and for example, a plurality of oblique grooves may be provided, or the grooves may be omitted.

  In the above embodiment, the micro switch is provided as the switch 14 for detecting the rise of the diaphragm 20. However, the type of the switch for detecting the approach of the striker 18 due to the rise of the diaphragm 20 is not limited thereto. Other proximity switches may be used.

  In the above embodiment, the present invention is applied to the pickling liquid level detector of the pickling tank, but the application target of the present invention is not limited to this, and the liquid level of the waste liquid of the wastewater treatment facility, etc. It is obvious that the liquid level detection can be generally applied.

Sectional drawing which shows the structure of embodiment of this invention Similarly, a bottom view showing a state where the bell-shaped opening is viewed from below Sectional drawing which shows the prior art described in patent document 1 Sectional drawing which shows the prior art which the applicant proposed in patent document 1

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Liquid level detector 12 ... Container 14 ... Switch 18 ... Striker 20 ... Diaphragm 22 ... Main body air piping 24 ... Source pressure air piping 24a ... Source pressure air 40 ... Pickling tank 42 ... Pickling liquid 50 ... Bell type opening 50a ... groove 52 ... lid

Claims (2)

A container in which a diaphragm having a switch and a striker for a switch is installed at a position below the switch;
A main body air pipe connected vertically to the lower part of the container;
A bell-shaped opening connected to the lower end of the main body air pipe;
A source pressure air pipe connected to the side of the bell-shaped opening;
A vertically openable and closable lid attached to the top of the bell-shaped opening in the main body air pipe;
A liquid level detector.   The liquid level detector according to claim 1, wherein a groove is provided on an inner surface of the bell-shaped opening.

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