JP2002340725A - Method for sensing leakage of cooling medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an infinitesimal leakage content of a cooling medium to be accurately sensed by being not liable to effect an influence of a temperature difference, an instrument error or the like to the medium. SOLUTION: A method for sensing the leakage of the cooling medium comprises the steps of detecting flow rates A and B of cooling water or the like at an inlet and an outlet of a flow passage by detectors 1 and 2, respectively, storing a difference of both the rates A and B obtained by an arithmetic unit 3 as an initial differential flow rate D, further obtaining a value obtained by multiplying the change amount (C-D) of the differential flow rate C from the rate D by a predetermined value α by an arithmetic unit 6, and monitoring the value to enable the value to be sensed and monitored with a small influence of the temperature difference, instrument error or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detection device capable of detecting minute leakage of a cooling medium in an apparatus or a plant which measures the flow rate of a cooling medium for cooling a cooling object at an inlet and an outlet of the cooling medium. About the method.

[0002]

2. Description of the Related Art Conventionally, as a method of this type, it is common to measure a flow rate of a cooling medium in an apparatus or a plant at an inlet / outlet of a cooling medium, and to monitor a difference flow rate.

[0003]

However, for example, when cooling a lance or sub-lance of a converter using cooling water, a cooling medium such as cooling water is affected by a temperature difference between an inlet and an outlet of the flow passage. Not only is it easy (especially in a batch plant), but there is a problem that errors occur due to variations in measuring instruments. Therefore, an object of the present invention is to make it difficult to be affected by a temperature difference, an individual difference of a measuring instrument, and the like, and to enable a minute difference flow rate to be accurately detected.

[0004]

In order to solve such a problem, according to the invention of claim 1, in a facility provided with flow meters at the inlet and the outlet of a flow path of a cooling medium for cooling an object to be cooled, After a lapse of a predetermined time after the state change of the equipment has occurred, the difference flow rate between the inlet and the outlet at that time is corrected to a zero point as a base point of the leak flow rate, and the cooling medium is monitored by monitoring the difference flow rate signal thereafter. Characterized in that minute leaks can be detected. In the first aspect of the invention, the flow rate difference between the inlet and the outlet can be constantly monitored (the invention of the second aspect). Here, the state change of the equipment corresponds to, for example, the start of blowing in the case of a lance of a converter which is a batch process. That is, the lance is lowered to start oxygen blowing, and at the same time, the heat generated by the decarburization reaction heats the lance and raises the temperature of the cooling water. The rate of temperature rise is initially high, gradually decreases, and approaches zero. When the temperature rise rate is high, the flow measurement system is not stable, and the measurement error is large. Therefore, at a timing when the flow rate measurement system becomes substantially stable after a predetermined time has elapsed from the start of blowing, the difference flow rate between the inlet and the outlet of the flow path is used as a base point for monitoring the leak flow rate. In the case of a continuous process, the state of the equipment may be changed, for example, by changing the absolute value of the cooling water flow rate itself.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram for explaining an embodiment of the present invention. 1, reference numerals 1 and 2 denote flow detectors such as an electromagnetic flow meter, 3 denotes a difference flow calculator, 6 denotes a subtraction / multiplier, and 8 denotes a device. Here, the apparatus 8 is assumed to be, for example, a lance or a sub-lance of a converter, but is not limited to this. Reference numerals 4 and 7 denote a monitoring device for monitoring the difference flow rate as a calculation result of the calculators 3 and 6, respectively, or a monitoring function and operation thereof.
Reference numeral 5 denotes a memory for storing the output of the arithmetic unit 3 or its contents (initial differential flow rate) in accordance with a command S given after a lapse of a predetermined time after the state change of the equipment has occurred.

That is, a cooling medium such as cooling water flows at its inlet and outlet by flow detectors 1 and 2 at flow rates A and B, respectively.
Is detected by the difference flow calculator 3 and the difference (AB) is calculated, and the difference flow is monitored as in the conventional case.
Then, the difference flow monitoring is performed for a predetermined time, and if the difference flow is within a certain range, a storage command S is issued and the difference flow rate C, which is the output from the difference flow rate calculator 3 at that time, is stored as the initial difference flow rate D (reference numeral). 5). The present invention regards this value D as the zero point (base point) of the difference flow rate, and further uses the subtraction / multiplier 6 to calculate the difference between the difference flow rate (change amount) C output from the difference flow rate calculator 3 and the above D. (CD) is obtained, amplified or multiplied by a predetermined coefficient (α), and the result is monitored (see reference numeral 7).

When the differential flow rate (AB) is out of the predetermined range, it is necessary not to issue the command S and to perform an operation such as issuing an alarm as an abnormality or stopping the operation. I do. By doing the above,
Complicated temperature correction becomes unnecessary, and it can be made independent of the accuracy of the instrument, thereby enabling highly accurate detection and monitoring.

[0008]

According to the present invention, a complicated temperature correction can be performed by monitoring a subsequent change based on a difference flow between the inlet and the outlet after a lapse of a predetermined time when the state of the apparatus has changed. Not only can it be unnecessary, but also the accuracy of the instrument can be almost neglected, and the advantage of high-precision monitoring can be obtained. Therefore, it can be said that the present invention is particularly suitable for a batch plant in which the operation is started and stopped frequently (repeatedly), rather than a plant in which the operation is continuously performed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an embodiment of the present invention.

[Explanation of symbols]

1, 2, flow rate detector, 3, differential flow rate calculator, 4, 7 differential flow rate monitor, 5 initial differential flow rate, 6 subtraction / multiplier, 8 apparatus (lance or sublance), S, differential flow rate storage Command.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuhiro Osu 1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (72) Inventor Shunji Matsumoto 20-1 Shintomi, Futtsu-shi, Chiba New Japan (72) Inventor Kiyomi Horikoshi 20-1 Shintomi, Futtsu City, Chiba Prefecture Nippon Steel Corporation Technology Development Headquarters (72) Inventor Seiji Matsuo 1-1 1-1 Tobata-cho, Tobata-ku, Kitakyushu, Fukuoka Prefecture Inside Nippon Steel Corporation Yawata Works (72) Inventor Taira Yakubo 1-1 1-1 Tobata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka F-term (reference) 2F030 CB02 CC19 CD11 CF11 2G067 AA34 BB02 CC01 DD04 EE09

Claims (2)

[Claims] 1. In a facility provided with a flow meter at each of an inlet and an outlet of a cooling medium for cooling a cooling object, after a lapse of a predetermined time after a change in the state of the facility,
The differential flow rate between the inlet and the outlet at that time is corrected to a zero point as a base point of the leak flow rate, and by monitoring the differential flow rate signal thereafter, a minute leak of the cooling medium can be detected. Cooling medium leak detection method. 2. The method according to claim 1, wherein the flow rate difference between the inlet and the outlet is constantly monitored.