JPH05187991A - Corrosion amount measuring device - Google Patents

Abstract

PURPOSE:To test samples in a case that temperature difference and voltage difference work on the sample simultaneously and to reproduce a condition which is very close to the operational condition of an actual engine, for instance. CONSTITUTION:A corrosion amount measuring device is provided with a ring shape path 2 and which is filled with a liquid 39 such as an anti-freeze liquid, a pump 4 which is provided to a part of the path, a test piece attaching part 5 which supports a pair of the test pieces 12 and 13 of aluminum and others each one surface of which contacts to the liquid 39, and heaters 20 and 21 which can heat up each the test piece 12 and 13 directly from behind sides thereof. Moreover, the device equipped with an electric circuit 26 which contains an electric power source 28, and is connected to the test pieces 12 and 13 to enable providing voltage difference between the teat pieces or just connecting the test pieces, a path part which is a part of the ring shape path 2 and of which axial line is actually horizontal as well as which is removable from the ring shape path 2 by an outlet and an inlet joints 34 and 33, and a cooling part 6 which can be cooled down the path part from outside thereof, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a specific physical condition such as the relationship between an engine made of an aluminum alloy in an operating state and an antifreeze coolant flowing in a passage formed inside the engine. The present invention relates to a corrosion amount measuring device for accurately measuring the amount of corrosion that occurs in a metal under a given condition, as well as performing an experiment easily on the state of metal corrosion that can occur due to the contact between a metal and a liquid under various conditions. .

[0002]

2. Description of the Related Art A paper entitled "Problems of Antifreeze and Anticorrosive Agents in Aluminum Engines" is published on pages 21 to 27 of the March 1973 issue of the magazine "Rust Prevention Management".
This paper summarizes the results of experiments and studies on the corrosion of aluminum engines by antifreeze cooling liquid (antifreeze liquid). Aluminum, which is usually considered not to be attacked by commercially available antifreeze liquid, is It has been reported that some parts may be attacked by antifreeze, which causes corrosion. Furthermore, a "heat transfer surface corrosion test device" has been proposed to test the condition.

[0003]

The "heat transfer surface corrosion test apparatus" proposed in the above-mentioned paper is a conventional test in which a test piece is simply immersed in a heated liquid to examine the progress of corrosion. Compared with the method, it is advanced in that it is possible to reproduce the state close to the actual operating state of the aluminum engine and investigate the corrosion state in that state. However, the cylinder block or cylinder head of an actual engine is often a part of some electric circuit, and a considerably strong current is generated due to, for example, the electric power of the ignition system or the AC electric power generated by the alternator. If the antifreeze contains an electrolyte substance, such as when there is a potential difference between the cylinder block and the cylinder head, the aluminum alloys that make up the antifreeze liquid are in an environment that is susceptible to corrosion in the electrochemical sense. However, the above-mentioned "heat transfer surface corrosion test apparatus" cannot create a state in which not only a temperature difference but also a potential difference is applied to the test piece.

According to the experiments conducted by the present inventors, the degree of corrosion of an aluminum engine by some antifreeze solution is not limited to the temperature difference, but when a potential difference is added to the temperature difference, the corrosion amount when they are added alone is It has been confirmed that corrosion far progresses far beyond the sum. In another page of the above paper, as a "radiator tube blockage test device", two aluminum test pieces are supported at intervals in a flow of heated antifreeze liquid, and an AC voltage is applied between them. Then, a device that simulates a situation in which a cooling pipe is blocked by a hydroxide or the like generated by corrosion of aluminum has been proposed. It is not possible to perform a test in which the voltage and the potential difference are applied at the same time.

These prior art test devices not only cannot perform a test when a temperature difference and a potential difference act on a test piece at the same time, but also facilitate the determination of corrosion products such as aluminum hydroxide. It also has the problem that it cannot be done. The present invention aims to provide an easy-to-use test apparatus capable of reproducing a state closer to the environment in which an actual engine is placed by further improving in order to solve the problems of the conventional art. It is the object of the invention.

[0006]

As a means for solving the above problems, the present invention provides an annular passage filled with a liquid to be tested and a liquid to be tested provided in a part of the annular passage. A pump capable of forcibly flowing, a test piece attachment part that supports a pair of test pieces so that one surface of each of the annular passages comes into contact with the liquid to be tested, and the test piece. A heater that can be heated directly from the back, an electric circuit that includes a power source and that is connected to the pair of test pieces and that can provide a potential difference between them or simply conduct electricity, and become a part of the annular passage. A cooling part having an axis which is substantially horizontal and which has a passage part which can be removed from the annular passage by means of inlet and outlet joints, the cooling part being able to cool the passage part from the outside, respectively. Equipped to provide a corrosion amount measuring device according to claim it is.

[0007]

The front surface of the pair of test pieces is in contact with the liquid to be tested, and the back surface of the test piece is directly heated by the heater. Therefore, the test piece is exposed to liquid from the metal side like the engine cylinder block and cylinder head. A temperature difference is given that transfers heat to the. Moreover, at the same time, a potential difference can be applied between the pair of test pieces by the power source of the electric circuit, so that a corrosive environment close to the operating state of the actual engine where the temperature difference and the potential difference simultaneously act can be easily created. It becomes possible to easily reproduce the actual state.

[0008] Corrosion products are separated from the liquid due to a decrease in solubility due to the cooling of the liquid to be tested in the cooling section which is a part of the annular passage, and the precipitation occurs in the passage section of the cooling section. Since the axis is substantially horizontal, it does not flow out together with the liquid, and stays in the passage in the cooling unit and is efficiently collected. The amount of corrosion products collected in the cooling section in this way can be easily and accurately measured with the passage section by removing the passage section of the cooling section at the inlet and outlet joints. Corrosion products can be metered.

[0009]

FIG. 1 schematically shows the overall structure of a corrosion amount measuring apparatus 1 which is an embodiment of the present invention. This device imitates a cooling water system of an engine and constitutes a passage for a liquid, which is composed of one annular passage 2 and an open passage 3 for opening the upper portion thereof to the atmosphere. These passages can be made of a material such as glass. This is not only because the liquid flowing inside can be observed due to the transparency, but also because the glass is an electrically insulating material, the current flowing through the annular passage 2 itself can be interrupted. Therefore, although metal pipes are unsuitable, it is possible to use hard pipes made of synthetic resin instead of glass.

The inside of the passage is filled with a liquid for the test, for example, an antifreeze liquid for cooling the engine. Circular passage 2
A pump 4 is provided in a part of the above, and the antifreeze liquid can be forcedly circulated in the direction of the arrow in the figure. If the drive speed of the pump 4 can be adjusted by a variable speed motor, a continuously variable transmission, or the like, the circulation amount of the antifreeze liquid can be arbitrarily changed, which is convenient. A test piece mounting portion 5 is formed in the downstream annular passage 2 of the pump 4, and a cooling portion 6 corresponding to the radiator of the engine is formed in the upstream annular passage 2.

The test strip mounting portion 5 is provided with projecting portions 7 and 8 of the passage 2 facing each other as shown in the drawing, which are provided with flanges 9 and 10 as shown in an enlarged view in FIG. ing. Test pieces 12 and 13 made of, for example, an aluminum alloy to be tested are screwed to these flanges 9 and 10 via a seal 11 in a liquid-tight manner. As the test pieces 12 and 13, other metallic materials such as cast iron and brass, or a combination thereof can be used.

The screwing method will be described in detail. As shown in FIG. 3, the heating block 15 having the flange 14 is the test piece 1.
It is advisable to place them so as to come into close contact with 2 and 13 from behind, and attach them to some extent elastically using bolts 16, nuts 17, compression springs 18, washers 19, and the like. Sheath heaters 20 and 21 are attached to the heating block 15 and generate heat when energized to heat the test pieces 12 and 13 directly from the side opposite to the antifreeze solution in the annular passage 2, that is, from the back. ing. Temperature sensors 22 and 23 are attached to the test pieces 12 and 13, respectively, and the temperature of the test pieces 12 and 13 can be measured by being pulled out by a lead wire.

Further, the lead wires 2 are attached to the test pieces 12 and 13.
4 and 25 are attached and they are connected to an electrical circuit 26 as shown in FIG. In the electric circuit 26, a variable resistor 27 and a power source 2 such as a battery
Either the urging circuit 29 composed of 8 or the short circuit 30 composed of a simple conductor wire can be selectively connected to the lead wires 24 and 25 by a changeover switch 31. The power supply 28 can be a constant voltage power supply or a constant current power supply. Although not shown, an ammeter may be provided on one of the lead wires 24 and 25, and a voltmeter or the like may be provided between the lead wires 24 and 25.

Although the cooling unit 6 in FIG. 1 is schematically shown, the actual structure is as illustrated in FIG. In the example of FIG. 2, what constitutes a part of the annular passage 2 is a curved pipe 32 made of brass or aluminum alloy wound in a coil shape, and the curved pipe 32 has an inlet and an outlet both located above the curved pipe 32. It can be easily disconnected from the annular passage 2 by means of suitable joints 33 and 34 provided on the. The curved pipe 32 is supported so as to be in the cooling water tank 35 in a state (posture) in which the axis of the curved pipe 32 is directed substantially horizontally.

Even when the straight pipe is used without the curved pipe 32, a part of the annular passage 2 in the cooling portion 6 can be separated from the annular passage 2 by means of the joints 33 and 34. Moreover, a part of the separable passage 2 is supported in the cooling water tank 35 in a substantially horizontal direction, whereby the test pieces 12 and 13 placed in the annular passage 2 are provided.
Substances produced by corrosion, such as the hydroxide of the above, are configured to easily stay in the separable portion of the annular passage 2. The cooling water tank 35 is provided with a cooling water inlet 36 and a cooling water outlet 37, and the cooling water 3
8 is supplied, for example, in a circulating manner to cool the curved pipe 32.

An open passage 3 connected to the upper part of the annular passage 2.
Is connected to the atmosphere by the tip of the annular passage 2.
The pressure of the antifreeze liquid 39 used for the internal test can be maintained at atmospheric pressure. A cooling device 40 may be provided in the open passage 3 as needed. Further, temperature sensors 41 are provided at various places in the annular passage 2 to measure the temperature of the antifreeze liquid 39 supplied to the test piece attachment part 5, and the cooling water tank 35 in the cooling part 6 is measured.
The temperature of the antifreeze liquid 39 can be maintained at a predetermined value by adjusting the supply amount of the cooling water 38 to the. Test pieces 12 and 13
It is also possible to keep the temperature detected by the temperature sensors 22 and 23 attached to the constant in the same manner.

Since the corrosion amount measuring apparatus 1 of the illustrated embodiment is constructed in this way, the test piece mounting portion 5 is provided with test pieces 12 and 13 such as the same aluminum alloy as the cylinder block and cylinder head of the engine. Bolt 1
6, the antifreeze liquid 39 is filled into the annular passage 2 from the open passage 3, and the antifreeze liquid 39 is circulated to the test piece attachment portion 5 by the pump 4 at an arbitrary flow rate. The temperature of the antifreeze liquid 39 is determined by the temperature and flow rate of the cooling water 38 supplied to the cooling unit 6.

The short circuit 30 is selected by the changeover switch 31 of the electric circuit 26, and the lead wires 24 and 25 are selected.
When the test pieces 12 and 13 are made to have the same potential via
The corrosion state due to the contact between the antifreezing liquid 39 in the annular passage 2 and the test piece 12 or 13 can be tested. At this position of the change-over switch 31, if the test pieces 12 and 13 are of the same kind, the amount of corrosion is usually small, but the test pieces 12 and 13 are heated from behind by the sheath heaters 20 and 21, and come into contact with the surface. When the temperature difference with the antifreezing liquid 39 is large, the amount of corrosion is relatively large. This is close to the state where the actual cylinder block and cylinder head are placed.

Even when the changeover switch 31 selects the short circuit 30, if the test piece 12 and the test piece 13 are made of different metals, the test pieces 12 and 13 and the antifreeze solution 39 are used.
A kind of battery is constituted by the electrolyte substance contained in the test piece 12 and the surface of the test piece 12 or 13 is ionized and eluted into the antifreeze solution 39 by the flow of current through the lead wires 24 and 25 and the short circuit 30. Corroded relatively quickly. When the test piece 12 and the test piece 13 have a large difference in ionization tendency, the corrosion rate becomes high.
Furthermore, if the sheath heaters 20 and 21 heat the test pieces 12 and 13 from the rear, the rate of corrosion increases significantly. This is different from the case where the antifreeze liquid is heated and tested, for example, when the test pieces 12 and 13 have a higher temperature than the antifreeze liquid 39, the corrosion further progresses.

Changeover switch 3 in electric circuit 26
When the energizing circuit 29 is selected by 1, a potential difference adjusted by the variable resistor 27 is applied between the power source 28 and the test pieces 12 and 13. In this case, the test piece 12
Even if 13 and 13 are made of the same metal, the degree of corrosion is generally large. When the test pieces 12 and 13 have a temperature difference with respect to the antifreeze liquid 39 by being heated by the sheath heaters 20 and 21, further progress of corrosion is the same as in the above case.

However, when the test piece 12 and the test piece 13 are made of different metals, the potential difference by the power source 28 is appropriately adjusted by the variable resistor 27, and the current direction is selected appropriately. Is a test piece 1 that is electrically biased.
It is also possible to suppress the ionization of 2 and 13 to prevent corrosion, and this corrosion amount measuring device 1 can also be used to find such preferable conditions.

Thus, the corrosion amount measuring device 1 of the embodiment
Can give a temperature difference to the antifreeze liquid 39 to the test pieces 12 and 13 and at the same time give a potential difference between them, so that a cylinder block or cylinder head of an actual engine in which a current such as an ignition system or an alternator is flowing. It is possible to easily reproduce a corrosive environment close to the above condition, and to perform measurement with high accuracy.

As the test pieces 12 and 13 are corroded, the metal forming them is changed to the antifreeze solution 39.
Almost all of the metal that has been eluted into the interior of the antifreeze solution 39 is dissolved in the antifreeze solution 39.
Furthermore, it binds to water and the like and forms a hydroxide such as aluminum hydroxide to separate from the antifreeze. In this embodiment, the cooling section 6 is provided in a part of the annular passage 2, and it has a structure as shown in FIG. 2 and the axis of the curved pipe 32 is placed in the horizontal direction, so that the components that are easily separated are provided. When the antifreeze liquid 39 containing the water passes through the curved pipe 32 of the cooling unit 6,
When the cooling water 38 removes heat and is cooled, the solubility is lowered and precipitation occurs. As a result, metal hydroxide and the like are bent into the bent pipe 32.
It is separated from the antifreeze liquid 39 inside, adheres to the pipe wall of the curved pipe 32 and stays in the pipe like mud. Therefore, the corrosion products are prevented from flowing through the cooling unit 6 and are efficiently collected in the curved pipe 32.

Since the curved pipe 32 can be easily separated from the annular passage 2 by the joints 33 and 34, the corrosion test is performed for a predetermined time, and after the corrosion is advanced as necessary, the curved pipe 32 is moved to the annular passage. By separating from 2, taking out to the outside, removing the liquid, and measuring its weight, and comparing it with the initial weight, the amount of the corrosion product can be measured relatively accurately. After the measurement, the corrosion product such as mud attached to the curved pipe 32 may be washed away with a cleaning agent or the like to be regenerated, and may be repeatedly used for the next measurement.

[0025]

According to the corrosion amount measuring device of the present invention, it is possible to easily obtain the same corrosion environment as an actual engine,
Since it is possible to create a state in which the temperature difference and the potential difference are simultaneously acting, it becomes easy to reproduce the actual corrosive environment. Moreover, since the corrosion product can be collected efficiently and its quantification is easy, the test and measurement are extremely easy and the measurement accuracy is improved. The invention not only allows the corrosion of the test piece in a particular liquid to be tested, but also allows the performance of a particular liquid, for example an antifreeze, to be tested.

[Brief description of drawings]

FIG. 1 is a schematic overall configuration diagram showing an embodiment of a corrosion amount measuring device of the present invention.

FIG. 2 is a schematic cross-sectional view showing an embodiment of a cooling unit.

FIG. 3 is a partial cross-sectional view showing an enlarged part of a test piece attachment part.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Corrosion amount measuring device 2 ... Annular passage 4 ... Pump 5 ... Test piece attachment part 6 ... Cooling part 12, 13 ... Test piece 15 ... Heating block 20, 21 ... Sheath heater 22, 23 ... Temperature sensor 26 ... Electric circuit 27 ... Variable resistor 28 ... Power source 29 ... Energizing circuit 30 ... Short circuit 31 ... Changeover switch 32 ... Curved tubes 33, 34 ... Joint 35 ... Cooling water tank 39 ... Antifreeze liquid 41 ... Temperature sensor

Claims (1)

[Claims] 1. An annular passage filled with a liquid to be tested, a pump provided in a part of the annular passage for forcibly flowing the liquid to be tested, and the pump in a part of the annular passage. A pair of test pieces including a test piece mounting portion that supports a pair of test pieces so that one surface of the test piece is in contact with the liquid to be tested, a heater that can directly heat the test piece from behind, and a power source. An electrical circuit connected to the pieces to provide a potential difference between them or to simply conduct them, and to form a part of the annular passage, the axis of which is substantially horizontal and the inlet and outlet joints A corrosion amount measuring device, comprising: a cooling part having a passage part that can be removed from the passage and capable of cooling the passage part from the outside.