JPH02679Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a freezing/thawing test device used for temperature change durability testing of various materials such as concrete, asphalt, and stone.

That is, test pieces obtained by molding the above-mentioned materials into shapes and dimensions of predetermined standards are repeatedly frozen and thawed a predetermined number of times within a certain temperature range, and then subjected to various strength tests to determine the actual results. The purpose of this research is to find out how well the materials used in the construction can withstand temperature changes in summer and winter, and how to make them able to withstand given temperature changes.

Conventionally, as a freeze/thaw test device, the special public
As shown in Publication No. 23034, a test tank and a reserve tank having the same heat capacity are provided, and the heat taken from the test tank is stored in the reserve layer to reduce the loss of heat. It was hot.

However, in this case, the heat is simply stored in the reserve tank, and the capacity of the reserve tank is
It hardly contributed to the repeated melting addition.

The present invention provides two test tanks with the same heat capacity, and when cooling the test piece in one test tank, the test piece in the other test tank is heated; By transferring the heat taken from one test tank to the other test tank, it is possible to reduce the loss of heat and reduce the capacity of the refrigerator. Explain in detail.

1 is a first test tank, the inside of which is filled with antifreeze such as calcium chloride, and in the antifreeze,
A container 3 containing a test piece 2 is provided, a heat exchanger 4 is provided, and a pump 5 for circulating the antifreeze in the first test tank is provided.

Reference numeral 6 designates a second test tank, the inside of which is filled with antifreeze such as calcium chloride, a container 3 containing the test piece 2 is provided in the antifreeze, a heat exchanger 7 is provided, and a second test tank is provided with the antifreeze. A pump 8 is provided for circulation in the test tank.

The first test tank 1 and the second test tank 6 have the same heat capacity, and the heat exchanger 4 and the heat exchanger 7 have the same heat capacity.

Further, the first test tank 1 and the second test tank 6 are each provided with a temperature sensing element (not shown) for detecting the temperature of the antifreeze solution.

Further, the heat exchangers 4 and 7 are connected to each other, and the connection is made as follows.

Both one end of the heat exchanger 4 and one end of the heat exchanger 7 are selectively connected to the refrigerant suction side and the refrigerant discharge side of the refrigerator 12 via valves 9 and 10 and a four-way switching valve 11. At the same time, one end of the heat exchanger 4 and one end of the heat exchanger 7 are connected via a check valve 13 and a valve 14 so that the refrigerant can flow into the heat exchanger 7.

Further, the other end of the heat exchanger 4 and the other end of the heat exchanger 7 are connected to a pair of check valves 1 facing in opposite directions.
5, 16, 17, 18, and the check valves 15, 17 facing in opposite directions are connected in series, and the check valves 16, 18 are connected in series. An expansion valve 19 is connected between the connection point of the check valves 16 and 18 and the connection point of the check valves 16 and 18.

A valve 20 and an external heat exchanger 21 are connected in series between the refrigerant discharge side of the refrigerator 12 and the connection point of the check valves 15 and 17.

Note that 22 is a fan that quickly dissipates heat held by the refrigerant flowing inside the external heat exchanger 21 into the atmosphere.

The operation of the test piece freezing/thawing adding apparatus having the above configuration is as follows.

Now, to explain the effect of repeatedly freezing and thawing test piece 2 in the range of -25℃ to 10℃ for a predetermined number of times, since the room temperature is usually higher than 10℃, The antifreeze filled in the second test tank 6 must be cooled to 10°C,
In this case, all the valves 9, 10, and 20 may be opened, and the four-way switching valve 11 may be switched to connect both the valves 9, 10 to the refrigerant suction side of the refrigerator 12. Therefore, the refrigerant that has taken heat from the antifreeze in the heat exchanger 4 is sent to the external heat exchanger 21 through the valve 9, the four-way switching valve 11, the refrigerator 12, and the valve 20, and is refrigerated in the heat exchanger 7. The refrigerant that has taken heat from the machine is sent to the external heat exchanger 21 through the valve 10, the four-way switching valve 11, the refrigerator 12, and the valve 20, and both refrigerants are released into the atmosphere while passing through the external heat exchanger 21. It is cooled by dissipating heat. Then, the cooled refrigerant is transferred to each check valve 1
6 and 18 to the heat exchangers 4 and 7, and by repeating the above operation, the temperature of the antifreeze inside both the first test tank 1 and the second test tank 6 can be lowered. (See area A in Figure 2).

After the temperature of the antifreeze drops to 10°C, the cooling of the antifreeze in the second test tank 6 is stopped by closing the valve 10, and the cooling of the antifreeze in the first test tank 1 is continued. Antifreeze in tank 1 -
It is possible to cool down to 25°C and maintain the antifreeze in the second test tank 6 at 10°C (see region B in Figure 2).

After cooling the antifreeze in the first test tank 1 to -25°C, close the valve 20 and close the valves 9 and 1.
0, open the four-way switching valve 11, connect the valve 9 to the refrigerant discharge side of the refrigerator 12, and connect the valve 10 to the refrigerant suction side of the refrigerator 12. Therefore, the refrigerant passing through the heat exchanger 7 can take heat from the antifreeze and give the heat of the refrigerant after passing through the refrigerator 12 to the antifreeze in the first test tank 1 while passing through the heat exchanger 4. Therefore, the antifreeze liquid in the second test tank 6 can be cooled and the antifreeze liquid in the first test tank 1 can be heated at the same time.

Incidentally, while performing this operation, the second test chamber 6
Since the thermal energy of the antifreeze in the first test tank 1 is used to heat the antifreeze in the first test tank 1, there is almost no loss of thermal energy, and since the condensation temperature of the refrigerant is low, power consumption is also low (1/3 of the conventional example). can do.

Furthermore, before the temperature of the antifreeze in the second test tank 6 drops to -25°C by performing the above operations, the temperature of the antifreeze in the first test tank 1 rises to 10°C.
When the temperature of the antifreeze in the first test tank 1 reaches 10°C, only the cooling of the antifreeze in the second test tank 6 is continued by closing the valve 9 and opening the valve 20 (see area C in Figure 2). ).

After cooling the antifreeze in the second test tank 6 to -25°C, close the valve 20 and close the valves 9 and 1.
0, open the four-way switching valve 11, connect the valve 10 to the refrigerant discharge side of the refrigerator 12, and connect the valve 9 to the refrigerant suction side of the refrigerator 12. The refrigerant passing through the heat exchanger 4 absorbs heat from the antifreeze in the first test tank 1, and the heat of the refrigerant after passing through the refrigerator 12 is transferred to the antifreeze in the second test tank 6 while passing through the heat exchanger 7. The antifreeze in the second test tank 6 can be heated at the same time as the antifreeze in the first test tank 1 is cooled.

When the temperature of the antifreeze in the second test tank 6 reaches 10°C, by closing the valve 10 and opening the valve 20, only the cooling of the antifreeze in the first test tank 1 is continued (the area in FIG. (See D).

Thereafter, by repeating the operations in area C and area D a predetermined number of times, a freeze/thaw test on the test piece can be performed.

In addition, in the above case, valves 9, 10, 2
The opening/closing of the four-way switching valve 11 and the switching operation of the four-way switching valve 11 shall be controlled by the output signal of the temperature sensing element.

When performing the above operations, the first test chamber 1 and the second
Freezing and thawing tests can be performed within the same temperature range in the opposite cycle to test chamber 6, so if the same number of test pieces are to be subjected to freezing and thawing tests, the capacity of each test chamber should be the same as before. The capacity of the refrigerator can be reduced to 1/2 of that in the example, and the capacity of the refrigerator can also be reduced to approximately 1/2.

As described above, the present invention reduces the capacity of the refrigerator required to perform freeze/thaw tests on test pieces by approximately half.
Not only can the heat loss be reduced, but also the condensation temperature of the refrigerant is low, so power consumption can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the freeze/thaw test apparatus of the present invention, and FIG. 2 is a diagram showing temperature changes in the antifreeze in both test tanks. 1, 6... Test tank, 2... Test piece, 3... Container, 4, 7... Heat exchanger, 5, 8... Pump,
9, 10, 14, 20... Valve, 11... Four-way switching valve, 12... Refrigerator, 13, 15, 16, 1
7, 18...Check valve, 21...External heat exchanger.

Claims (1)

[Scope of utility model registration request] A heat exchanger is installed in each of the two test tanks having the same heat capacity, and one of the four-way switching valves is connected to the pipe line of each one of the heat exchangers through a valve in the middle.
and connecting each secondary side of the four-way switching valve to the primary side and secondary side of the refrigerator, respectively,
forming a side path between both pipes leading from both exchangers to the valve by connecting a check valve and a valve in series;
The other pipe line of both heat exchangers is connected in parallel by two opposing series check valves and two backward series check valves, and between adjacent points of the two sets of series check valves. An expansion valve is connected to the refrigeration machine, and an external heat exchanger is interposed and connected between an adjacent point of the opposed series check valve and the secondary side of the refrigerator via a valve. Test equipment.