JPH0693479A - Cooling device of electronic computer - Google Patents

Abstract

PURPOSE:To execute corrosion pre-inhibition of a cooling device by replenishing a corrosion inhibitor corresponding to a measured result of an absorption characteristic of white light out of a mixed corrosion inhibitor added to a cooling water. CONSTITUTION:The mixed corrosion inhibitor consisting of BTA and a molybdate is added to a cooling water 1 in the cooling device 5 of an electronic computer, the absorption characteristic of the white light out of respective corrosion inhibitors is measured and the corrosion inhibitor is replenished in the cooling water corresponding to the measured absorbance value in respective wave lengths. Since the mixed corrosion inhibitor exists in the cooling water in the cooling device and the corrosion inhibitor is automatically replenished by detecting the concentration condition of the corrosion inhibitor, the corrosion of the cooling device is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the prevention of corrosion of a cooling device for an electronic computer, and more particularly to a cooling device for an electronic computer capable of easily managing a corrosion inhibitor.

[0002]

2. Description of the Related Art As the capacity and speed of electronic computers have increased, the heat generation density of LSIs used in electronic computers has greatly increased, and measures for heat dissipation have become important. Conventionally, a cooling method of a computer has been a so-called forced air cooling method, that is, a cooling method by blowing air from a fan.
Along with the increase in the heat generation density of I, the air cooling is being shifted to a water cooling system having a higher cooling efficiency. The water cooling device is composed of a cooling structure in contact with a semiconductor element such as an LSI, a heat exchanger, a circulation pump, and piping connecting them. When the cooling water flows through the internal flow path of the cooling structure, it takes heat from the semiconductor element to increase its temperature, is cooled by the heat exchanger, and is circulated again. Pure water is used as the cooling water, and an ion exchanger for purifying the cooling water is built in the device (Japanese Patent Laid-Open No. 2000-242242).
63-15317 and 63-251779). Further, a copper-based material having high thermal conductivity is used for the heat exchange part of the cooling device, and stainless pipe or resin pipe is used for the pipe part.

[0003]

The prior art described above takes into consideration the cooling efficiency and maintainability of the electronic computer.
It is difficult to say that sufficient consideration is given to corrosion of the cooling system. That is, a copper-based material having high thermal conductivity is used for the heat exchange part of the cooling system, a stainless steel pipe or a copper pipe is used for the pipe, and Sn-Ag solder or Ag-Cu braze is used for the joining material.
Corrosion of these materials is a problem even if ion-exchanged pure water is used as cooling water. As a means for preventing corrosion of metallic materials, a method of removing dissolved oxygen in cooling water or a method of controlling the copper ion concentration in cooling water is known.
However, it is difficult to say that the former is a sufficient method such as laying high-pressure inert gas such as argon gas for deoxidation, and the latter is high-purity water from which metal ions have been removed to promote corrosion of copper.
In addition to the above, recently, a method for preventing corrosion by adding a corrosion inhibitor to cooling water has been investigated. This method can suppress corrosion of metal materials more easily than the above two methods, but requires equipment other than a normal cooling device such as concentration control of a corrosion inhibitor and maintenance. In particular, in a cooling device for an electronic computer, which is formed from a plurality of types of metal materials, in which cooling water to which a plurality of types of corrosion inhibitors, which selectively show anticorrosion performance for a plurality of types of metal materials, are circulated,
The conventional method of sampling and analyzing to investigate the concentration of the corrosion inhibitor is inefficient and cannot be said to be a sufficient method, and there is a problem in terms of corrosion resistance.

An object of the present invention is to easily control the concentration of a corrosion inhibitor in a computer cooling device to which a plurality of types of corrosion inhibitors are added in order to prevent corrosion of a cooling device using a wide variety of constituent materials. An object of the present invention is to provide a cooling device for an electronic computer equipped with a device capable of

[0005]

In the cooling device for a computer of the present invention, the concentration of the corrosion inhibitor contained in the circulating cooling water in the device is constantly monitored, and the concentration is kept stable. This device is designed to suppress corrosion, and the gist of the present invention is as follows.

(1) In a cooling device of an electronic computer in which a cooling medium containing a plurality of types of corrosion inhibitors, which selectively show anticorrosive properties for a plurality of types of metal materials, is circulated, each corrosion inhibition in the cooling medium is suppressed. A cooling device for an electronic computer, comprising: a means for measuring the white light absorption characteristics of the agent; and a concentration detecting means for determining the concentration of the corrosion inhibitor from the measured absorbance values at each wavelength of the white light.

(2) In a cooling device of an electronic computer in which a cooling medium to which a plurality of types of corrosion inhibitors, which selectively show anticorrosive properties for a plurality of types of metal materials, is circulated, is used the corrosion inhibitor as the cooling medium. Corrosion inhibitor replenishing means to be replenished in, and means for measuring the white light absorption characteristics of each corrosion inhibitor in the cooling medium, the measured value of the absorbance at each wavelength of white light is a predetermined width from the reference value Injecting the corrosion inhibitor into the cooling medium when it decreases, equipped with a control means for outputting a control signal to the corrosion inhibitor replenishing means to stop the addition of the corrosion inhibitor when the measured value is restored to the reference value Electronic computer cooling system.

(3) In an electronic computer having a cooling structure closely attached to a semiconductor module, which is a central processing unit of the electronic computer, and a cooling device connected to the cooling structure,
An electronic computer in which the cooling device is provided with a control means including (1) and (2).

[0009]

[Function] Copper easily corrodes in contact with circulating cooling water in a cooling device open to the atmosphere, forming a film of oxide or hydroxide on the surface, and part of it in the cooling water as ions. Elute. The copper ions eluted in the cooling water are reduced and deposited on metals such as stainless steel pipes that are baser than copper. Local corrosion damage such as pitting corrosion, crevice corrosion or stress corrosion cracking occurs at the reduced precipitation portion, which causes leakage of cooling water.
Then, as a result of various studies on corrosion inhibitors effective for preventing corrosion of copper and stainless steel, it was found that a mixed corrosion inhibitor of benzotriazole (BTA) and molybdate is effective. Further, it was found that this mixed corrosion inhibitor is also effective for Sn-Ag solder and Ag-Cu brazing material for the joint material. That is, molybdate has an effect of passivating the Sn surface, which is the main component of the solder material, while the Ag-Cu brazing material has a high anticorrosion effect of BTA, and Ag and Cu are protective against BTA. It is thought that this is because a compound film having a high degree of formation is formed. The method for controlling the concentration of mixed corrosion inhibitors is to install a spectrophotometer that measures the white light absorption characteristics of the corrosion inhibitor in the cooling water in the cooling water path, and measure the corrosion of each corrosion from the measured value of the white light at a specific wavelength. This can be achieved by providing means for detecting the concentration of the inhibitor.
A feature of the present invention is to image-process the peak intensity ratio of a specific wavelength of white light to measure the concentration of the corrosion inhibitor. That is, 270 nm for BTA and 220 n for molybdate.
It is only necessary to measure the peak value of absorbance at m, and in the case of mixing, the peak value of concentration and the peak value of absorbance are in a proportional relationship that always maintains a ratio of 7 to 1, so the difference between the peak value of mixing at 220 nm and the peak value of BTA. Is the concentration of molybdate, and similarly, the difference between the peak value of the mixture at 270 nm and the peak value of molybdate is the concentration of BTA.
Therefore, the concentration state of the mixed corrosion inhibitor can be known by obtaining the respective peak intensity ratios at 270 nm and 220 nm.

As described above, the BT is used in the cooling device of the electronic computer.
A cooling water containing a mixed corrosion inhibitor consisting of A and molybdate is circulated, and a white light absorption characteristic measurement system of the corrosion inhibitor, a corrosion inhibitor injection system, and a control system for injecting the corrosion inhibitor into the cooling system It became clear that the cooling device of the electronic computer has high reliability by providing the.

[0011]

FIG. 1 is a system diagram of a computer cooling device of the present invention.
Shown in. Cooling water 1 is cooling water containing a mixed corrosion inhibitor. This cooling water 1 is sent by a pump 2 to a cooling unit 3 of a module having a plurality of LSI elements of an electronic computer, and the LSI elements that have been heat-exchanged to generate heat are cooled, and at the same time, the cooling water 1 is heated. Then, it is flowed into the cooling water tank 4. The cooling water 1 discharged from the cooling water tank 4 is sent to the cooler 5 by the pump 2. The cooler 5 is provided with a heat exchanger 7 connected to the refrigerator 6, and the cooling water 1 that has been heated by cooling the heating element of the electronic computer is cooled again in the cooler 5. Then, the cooling water 1 discharged from the cooler 5 is controlled by the flow rate control device 8 and sent to the cooling unit 3 of the electronic computer.
A spectrophotometer 9 and a controller 10 for controlling the concentration of the corrosion inhibitor are installed in the cooling water system. Spectrophotometer 9
Then, the absorbance at the wavelengths of 270 nm and 220 nm in the cooling water is measured by the flow cell, and the controller 10 directly processes the concentration of the corrosion inhibitor directly by performing image processing of the peak intensity ratio of each absorbance and measuring. Further, the control device 10 includes a pump 12 and a flow rate control valve 1 for introducing the corrosion inhibitor in the corrosion inhibitor storage tank 11 into the system.
3 are connected. The control unit 10 analyzes the concentration state of the corrosion inhibitor from the measured peak intensity value based on the correlation between the reference value of the peak intensity and the corrosion inhibitor concentration which is input in advance. If the measured value becomes equal to or less than the set value by analysis, the pump 12 is operated and the flow control valve 13 is opened according to an instruction from the control device 10.
The corrosion inhibitor in the corrosion inhibitor storage tank 11 is introduced into the cooling system. If the measured value returns above the set value, the control device 10 is restarted.
, The pump 12 is automatically stopped, the flow control valve 13 is closed, and the cooling module 1 of the computer is cooled by the cooling water 1 containing the corrosion inhibitor component that has returned to the normal concentration.

The corrosion inhibitor storage tank is provided separately for the inorganic corrosion inhibitor and the organic corrosion inhibitor, and the control device 10 is provided.
The corrosion inhibitors may be replenished in the system independently of each other based on the signal from the.

Next, an embodiment forming the basis of the present invention will be described with reference to FIGS. FIG. 2 shows, as an example, the results of examining the effect of BTA concentration on the amount of corrosion of copper by conducting a corrosion test for 200 hours in pure water at 40 ° C. and 2 m / s, simulating in a cooling water environment. From the figure, corrosion of copper can be suppressed if the BTA concentration is 5 ppm or more. Here, the effective concentration range of the corrosion inhibitor is from 5 ppm to 2 × 10 ⁴ ppm. This is because at low addition concentrations, there is no corrosion inhibiting effect,
At high addition concentrations, a precipitate is formed due to the solubility of BTA,
This is because the precipitate floats in the system and adheres to the heat transfer section and causes troubles such as deterioration of cooling performance. The mixing ratio of the mixed corrosion inhibitor is 1:10 to 10 :.
It is effective in the range of 1, but preferably 1: 1.

FIG. 3 shows BTA, molybdate and BTA.
The results of measuring the respective absorption curves by the absorptiometric method of white light in the case of mixing and molybdate are shown. In each case, the concentration was 10 ppm. From the figure, the absorption curve in the case of mixing is at the position where the absorption curves of BTA and molybdate are added at any wavelength. Therefore, in the case of mixing, the concentration of each corrosion inhibitor can be estimated by subtracting each absorption curve from the absorption curve. That is, the wavelength 270n
The absorption peak of m indicates the concentration of BTA regardless of the molybdate concentration, and the absorbance composition at the wavelength of 220 nm is the absolute value of 1/7 of the absorbance of BTA obtained from the absorbance of molybdate and the absorption peak at 270 nm. Consistency of the values can be used to estimate the concentration of molybdate and the concentration of BTA from the absorbance at two wavelengths.

Thus, according to the present invention, the corrosion inhibitor concentration can be easily controlled by measuring the white light absorption characteristics of the corrosion inhibitor and comparing the measured absorbance values at each wavelength.

[0016]

According to the cooling device for the electronic computer of the present invention, the state of the concentration of the mixed corrosion inhibitor in the cooling water can be grasped, the consumption amount thereof is detected, and the corrosion inhibitor of the corrosion inhibitor is automatically detected by the control device. Since replenishment is possible, troubles such as leakage of cooling water due to corrosion of the cooling device can be prevented in advance.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a computer cooling device of the present invention.

FIG. 2 is an explanatory diagram showing a corrosion inhibiting effect of a corrosion inhibitor according to an embodiment of the present invention.

FIG. 3 is a white light absorption characteristic diagram of a corrosion inhibitor according to an embodiment of the present invention.

[Explanation of symbols]

1 ... Cooling water, 2 ... Pump, 3 ... Module cooling unit, 4 ...
Cooling water tank, 5 ... Cooler, 6 ... Refrigerator, 7 ... Heat exchanger, 8 ... Flow control device, 9 ... Spectrophotometer, 10 ... Control device, 11 ... Corrosion inhibitor storage tank, 12 ... Pump, 13 ... Flow control valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noriyuki Onaka 4026 Kujimachi, Hitachi City, Ibaraki Prefecture Hitachi Research Laboratory, Ltd. (72) Inventor Kenichi Kasai 1 Horiyamashita, Hadano City, Kanagawa Prefecture Factory Kanagawa factory

Claims (7)

[Claims] 1. A cooling device for an electronic computer, comprising a plurality of types of metal materials, and circulating a cooling medium to which a plurality of types of corrosion inhibitors, which selectively show corrosion resistance with respect to the plurality of types of metal materials, are circulated. In, a means for measuring the white light absorption characteristics of each corrosion inhibitor in the cooling medium, and a concentration detecting means for determining the concentration of the corrosion inhibitor from the measured value of the absorbance at each wavelength of white light. Characteristic computer cooling device. 2. A cooling device for an electronic computer in which a cooling medium, which is composed of a plurality of types of metal materials, and to which a plurality of types of corrosion inhibitors that selectively exhibit anticorrosion performance with respect to the plurality of types of metal materials is added, circulates. In, a corrosion inhibitor replenishing means for replenishing the corrosion inhibitor in the cooling medium, and a means for measuring the white light absorption characteristics of each corrosion inhibitor in the cooling medium, each wavelength of white light Injecting a corrosion inhibitor into the cooling medium when the measured value of the absorbance at a predetermined width is reduced from the reference value, a control signal for stopping the addition of the corrosion inhibitor at the time when the measured value is restored to the reference value. A cooling device for an electronic computer, comprising: a control unit that outputs the corrosion inhibitor replenishing unit. 3. The cooling device for a computer according to claim 1, wherein the corrosion inhibitor is a mixture of an inorganic oxidant type molybdate and an organic benzotriazole and its derivative. 4. The white light absorption characteristic measuring means of the corrosion inhibitor according to claim 3, wherein wavelengths are 270 nm and 220 nm.
Cooling device for electronic calculator, which is a spectrophotometer capable of measuring the absorbance at. 5. The cooling device for an electronic computer according to claim 3, wherein the corrosion inhibitor concentration detecting means measures the concentration of the corrosion inhibitor by image-processing the peak intensity ratio at a wavelength of 270 nm and a wavelength of 220 nm. 6. The method according to claim 5, wherein the absorption peak at a wavelength of 270 nm indicates the concentration of benzotriazole regardless of the molybdate concentration, and the absorbance composition at a wavelength of 220 nm is the absorbance of molybdate and the absorption peak at 270 nm. 1/7 of the absorbance of benzotriazole obtained from
The cooling device for an electronic computer, which uses as an image processing method to estimate the concentration of molybdate and the concentration of benzotriazole from the absorbances of the above two wavelengths by using the absolute value of. 7. A cooling structure closely attached to a semiconductor module, which is a central processing unit of the electronic computer, and a cooling device connected to the cooling structure according to claim 1, 2, 3, 4, 5 or 6. An electronic computer in which the cooling device is provided with a corrosion inhibitor for the electronic computer and a control means for controlling the concentration thereof.