JP4176708B2 - Material testing equipment - Google Patents

Description

  The present invention relates to a material testing apparatus that includes a thermostatic bath and performs a material test at various set temperatures.

  Conventionally, various improved material testing machines for evaluating material performance have been used. For example, in the material testing machine of patent document 1, the technique for evaluating a some material on the same temperature conditions is disclosed, without providing a thermostat.

Further, Patent Document 2 discloses a material testing machine including a thermostatic chamber (atmosphere furnace) that can test materials under the same temperature condition.
JP 2003-344248 A JP 2001-183275 A

  Patent Document 1 discloses a material testing machine that reduces labor for comparing test data performed under various conditions under the same conditions. For example, when the temperature conditions are different, a preset correction value is stored in a memory, and the apparatus is configured so that the correction can be automatically performed, thereby reducing the labor of the operator.

  However, this is not suitable for tests where temperature and humidity are very important parameters. For example, when evaluating the adhesive strength of an adhesive, it is impossible to identify the tests performed under different temperature conditions and humidity conditions by correction. In order to know the durability of the material, it is ideal to test with a material testing machine equipped with a thermostatic chamber.

  Patent Document 2 equipped with a thermostatic bath describes a configuration for improving the test accuracy by making the temperature of the test piece (material) uniform. Therefore, the material testing machine of Patent Document 2 can perform a material test with higher accuracy than the material testing machine of Patent Document 1.

  However, not only the test piece but also the actuator (support member) that supports the test piece is affected by the temperature in the thermostatic chamber. The conventional material testing machine including the constant temperature bath including the material testing machine of Patent Document 2 does not consider the influence of the temperature that the actuator receives at all, which may adversely affect the test accuracy.

  Accordingly, the present invention provides a material testing apparatus capable of realizing good test accuracy by taking into account the amount of expansion and contraction accompanying the temperature change of the support member that supports the material in the thermostat even when the temperature in the thermostat is changed. The purpose is to provide.

In order to solve the above-described problems, the material testing apparatus according to the first aspect of the present invention includes a thermostatic chamber, and supports the material and supplies an external force to the material in the material testing apparatus that performs the material test in the thermostatic chamber. The temperature detecting means for detecting the temperature of the inner portion of the thermostatic chamber of the support member is provided, and the expansion / contraction amount calculating means for deriving the expansion / contraction amount due to the temperature change of the support member from the temperature value detected by the temperature detection means is provided, and the expansion / contraction of the support member is provided. The reference position for measuring the length of the material by the amount is corrected, a load detecting means for detecting the load applied to the material is disposed on the outer part of the thermostatic chamber of the support member, and the support member is cooled. A cooling means that can suppress the heat in the thermostatic chamber from being transmitted to the load detecting means, and the thermostatic bath is provided with a through hole that allows the support member to pass through, and the thermostatic bath is provided inside and outside the thermostatic bath. Higher than the atmospheric pressure An elastic tube containing a body is disposed, the elastic tube is in close contact with the wall surface of the through hole, a hole is provided in the elastic tube, and gas in the elastic tube is blown toward the support member from the hole. .

The material testing apparatus of the invention of claim 2 includes a thermostatic chamber, and in the material testing apparatus for performing a material test in the thermostatic chamber, the inner portion of the thermostatic chamber of a support member that supports the material and supplies an external force to the material Temperature detecting means for detecting the temperature of the recording medium, and a recording means for recording the temperature value detected by the temperature detecting means in association with the amount of expansion and contraction due to the temperature change of the support member at the temperature value is provided, and the temperature detecting means Load detecting means for detecting a load applied to the material by correcting a reference position for measuring the length of the material by the amount of expansion / contraction of the supporting member recorded in the recording means corresponding to the detected temperature value was placed in the thermostatic chamber outer portion of the support member, the support member is cooled, heat of the thermostatic chamber is provided with a cooling means enabling prevented from being transferred to the load detecting means, the constant-temperature bath Before A through hole is provided for penetrating the support member, and an elastic tube containing gas at a pressure higher than the pressure inside and outside the thermostatic chamber is disposed in the through hole, and the elastic tube is in close contact with the wall surface of the through hole, and the elastic A hole was provided in the tube, and the gas in the elastic tube was blown from the hole toward the support member.

The material testing apparatus according to the invention of claim 3 includes a constant temperature bath, and a material test device for performing a material test in the constant temperature bath. The inner portion of the constant temperature chamber of the support member that supports the material and supplies an external force to the material. Temperature detecting means for detecting the temperature of the support member, and an expansion / contraction amount calculating means for deriving the expansion / contraction amount due to the temperature change of the support member from the temperature value detected by the temperature detection means. The reference position for measuring the thickness is corrected, a through hole is provided in the thermostatic chamber to allow the support member to pass through, and an elastic tube containing a gas higher in pressure than the pressure inside and outside the thermostatic chamber is disposed in the through hole. The elastic tube is in close contact with the wall surface of the through hole, and a hole is provided in the elastic tube so that gas in the elastic tube is blown from the hole toward the support member.

The material testing apparatus according to claim 4 is a material testing apparatus comprising a thermostat and performing a material test in the thermostat, and supporting the material and supplying an external force to the material. Temperature detecting means for detecting the temperature of the recording medium, and a recording means for recording the temperature value detected by the temperature detecting means in association with the amount of expansion and contraction due to the temperature change of the support member at the temperature value is provided, and the temperature detecting means A reference position for measuring the length of the material corresponding to the amount of expansion and contraction of the support member recorded in the recording means corresponding to the detected temperature value is corrected, and the penetration through which the support member penetrates the thermostat A hole is provided, and an elastic tube containing gas having a pressure higher than the pressure inside and outside the thermostatic chamber is disposed in the through hole. The elastic tube is in close contact with the wall surface of the through hole, and the hole is formed in the elastic tube. Only, and the blown gas in the elastic tube toward the support member from the hole.
It is preferable that the holes are provided annularly at a plurality of locations so that the gas is blown evenly around the support member.
The gas in the elastic tube is preferably dry air or the same kind of gas as that in the thermostatic bath.

When the invention of claim 1 is carried out, the temperature detection means can measure the temperature of the support member inside the thermostatic chamber, and the expansion / contraction amount due to the temperature change of the support member can be grasped from the expansion / contraction amount calculation means and the actually measured temperature value. can do. In addition, since the reference position for measuring the length of the material can be corrected by the amount of expansion / contraction of the support member, the accuracy of the material test can be improved. Furthermore, a load detecting means for detecting a load applied to the material is arranged on the outer part of the thermostatic chamber of the support member, and a cooling means is provided that makes it possible to suppress the heat in the thermostatic bath from being transmitted to the load detecting means. Therefore, the load detection means is not affected by heat and can maintain good detection accuracy.
In addition, a through-hole for allowing the support member to pass through the thermostatic chamber is provided, and an elastic tube containing a gas higher in pressure than the pressure inside and outside the thermostatic chamber is disposed in the through-hole so that the elastic tube is in close contact with the wall surface of the through-hole. Therefore, it is possible to make it difficult for the air in the thermostatic chamber to leak to the outside. Thereby, the change of the environment in a thermostat can be suppressed.
Further, since air is blown toward the support member from the hole provided in the elastic tube, an air curtain is formed between the elastic tube and the support member, and the outside air is kept at a constant temperature from between the elastic tube and the support member. It is possible to prevent the gas from flowing into the bath or outflow of the gas in the thermostatic bath to the outside. In addition, since the elastic tube and the support member are not in contact, even if the support member enters and exits the thermostatic chamber during the material test, friction does not occur between the elastic tube and the support member. The result can be obtained.

  When the invention of claim 2 is carried out, the temperature detecting means can measure the temperature of the supporting member inside the constant temperature bath, and has a recording means for recording the amount of expansion and contraction due to the temperature change of the supporting member at the measured temperature value. Therefore, the expansion / contraction amount of the support member can be grasped. In addition, since the reference position for measuring the length of the material can be corrected by the amount of expansion / contraction of the support member, the accuracy of the material test can be improved. Further, similarly to the first aspect, the load detection means is not affected by heat and can maintain good detection accuracy.

In the third and fourth aspects of the invention, air is blown toward the support member from the hole provided in the elastic tube as in the first and second aspects of the invention. An air curtain is formed, and it is possible to prevent the outside air from flowing into the thermostatic chamber and the gas in the thermostatic bath from flowing out from between the elastic tube and the support member.
In addition, since the elastic tube and the support member are not in contact, even if the support member enters and exits the thermostatic chamber during the material test, there is no friction between the elastic tube and the support member. The result can be obtained.

  When the gas flows out from the hole, the air that flows out from the elastic tube forms a layer, so that the air outside the thermostatic chamber flows into the thermostatic chamber through the gap between the elastic tube and the support member. Can be prevented. The temperature of the gas in the elastic tube is almost the same temperature as the gas in the thermostat, so even if it flows into the thermostat, the temperature change in the thermostat is so small that it can be ignored, changing the environment in the thermostat. You do n’t have to.

  FIG. 1 is a longitudinal front view of a test apparatus main body 2 provided with a thermostatic chamber 4 capable of carrying out the present invention, and FIG. 2 is a side view of a part of the test apparatus main body 2 longitudinally cut. FIG. 3 is a plan view of the test apparatus main body 2. As shown in FIG. 1, the test apparatus main body 2 includes a fixed unit 30, a drive unit 37, and a movable unit 38.

First, the configuration of the fixing unit 30 will be described.
The thermostat 4 can be set to an arbitrary temperature within a range of minus 40 ° C. to plus 150 ° C., for example, and the material test is performed in this temperature range. Depending on the material to be tested and the purpose of the test, the temperature range to be set can be arbitrarily selected without sticking to the above temperature range.

  A plate 36 is installed on the upper wall 20 of the thermostatic chamber 4, and four brackets 28 are fixed on the plate 36. A plurality of support posts 6 (two shown in FIG. 1) are fixed to the upper surface of the bracket 28. A connecting member 12 is installed in the middle of the column 6, and a top plate 7 is installed at the upper end of the column 6.

  Further, the support column 16 is fixed to the lower surface of the bracket 28 through the upper wall 20 of the thermostatic chamber 4 and the plate 36. A bottom plate 27 is fixed to the lower end of the support column 16, and the lower gripping portion 15 is installed on the bottom plate 27. The top plate 7, the support column 6, the connecting member 12, the bracket 28, the support column 16, the bottom plate 27, and the lower gripping unit 15 constitute a fixing unit 30. A portion above the bracket 28 of the fixed portion 30 is accommodated in the case 26.

Next, the configuration of the drive unit 37 will be described.
The top plate 7 is provided with a hole through which the ball screw 8 passes. The upper part of the ball screw 8 passes through a hole in the top plate 7, and a gear 23 is fixed to the upper end of the ball screw 8. That is, the gear 23 is disposed above the top plate 7. On the other hand, the lower end of the ball screw 8 is rotatably supported by the connecting member 12.

  As shown in FIG. 2, the gear 23 is connected to the drive motor 21 via the intermediate gear 22. By driving the drive motor 21, the ball screw 8 integrated with the gear 23 can be rotated. It has become. A drive unit 37 is configured by the drive motor 21, the intermediate gear 22, the gear 23, and the ball screw 8.

Next, the configuration of the movable part 38 will be described.
As shown in FIG. 1, a precision ball screw 10 is screwed onto the ball screw 8. The precision ball screw 10 is provided with an engaging portion 10a. By engaging the engaging portion 10 a with a groove (not shown) provided in the support 6, a linear guide for the precision ball screw 10 is configured. By rotating the ball screw 8, the precision ball screw 10 can be moved up and down along the ball screw 8.

  The precision ball screw 10 is provided with a needle 31 that serves as a mark for recognizing the reference position of the indicator 29 arranged inside the case 26. The position of the precision ball screw 10 is set in advance so that the needle 31 indicates zero at room temperature. When the inside of the thermostatic chamber 4 becomes high temperature, the heated support member 13 expands, and the position of the index 29 pointed to by the needle 31 is shifted from the reference position by the amount of expansion.

  A load cell 9 (load detection means) is connected to the lower end of the precision ball screw 10 via a plurality of rods 11 (two are shown in FIG. 1). Further, a support member 13 is installed at the lower end of the load cell 9. At the lower end of the support member 13, an upper grip 14 that holds the upper end of the material to be tested is installed. The precision ball screw 10, the rod 11, the load cell 9, the support member 13, and the upper gripping part 14 constitute a movable part 38.

  As shown in FIG. 1, a driving unit 37 is fixed to the fixed unit 30, and a movable unit 38 is driven by the driving unit 37 so as to reciprocate up and down along the fixed unit 30. The material testing apparatus 1 of the present invention further includes the following configuration.

  The support member 13 passes through a through hole 4 a provided in the upper wall 20 of the thermostatic chamber 4, and the upper gripping portion 14 is disposed inside the thermostatic chamber 4. A groove 4b for arranging an O-ring or an elastic tube 5 described later in detail is formed in the opening portion on the upper side of the through hole 4a. The elastic tube 5 is disposed in the groove 4b, and the upper portion of the elastic tube 5 is pressed by the plate 36.

  In the elastic tube 5, dry compressed air is supplied from the compressor 24 via a pipe 25. The elastic tube 5 is in close contact with the wall surface of the through hole 4a, but is separated from the support member 13.

  FIG. 5 is a schematic plan view of the elastic tube 5. As shown in FIG. 5, the elastic tube 5 includes branch portions 5 a to 5 d, and the branch portions 5 a to 5 d surround the support member 13.

The structure of the branch portions 5a to 5d of the elastic tube 5 is shown in a perspective view in FIG.
As shown in FIGS. 5 and 6, a plurality of holes 35 are provided in the branch portion 5d (the same applies to the branch portions 5a to 5c). Dry air flows out from the hole 35 into the thermostat 4 and is blown onto the support member 13. As a result, a part of the dry air in the elastic tube 5 flows into the thermostat 4, but the outside air can be prevented from flowing into the thermostat 4.

  That is, it is possible to prevent the dry air in the elastic tube 5 from flowing out of the holes 35 to form an air curtain and preventing the gas (in some cases, steam) in the thermostat 4 from flowing out of the thermostat 4. it can.

  Even if the four support members 13 are individually moved upward or downward, the inner and outer sides of the thermostat 4 (FIG. 1) are blocked by the air curtain described above at the branch portions 5a to 5d. .

  FIG. 7 is a front view of an elastic tube 39 which is a modification of the elastic tube 5 shown in FIG. 5 and 6, the elastic tube 5 surrounds the support member 13 over substantially one round, whereas the branch portions 39a to 39d of the elastic tube 39 shown in FIG. It is installed around 2 and a half laps. The branch portions 39a to 39d are provided with holes (not shown) similarly to the branch portions 5a to 5d. As described above, when the support member 13 is surrounded by multiple layers, the inside and outside of the thermostatic chamber 4 can be well blocked.

  As shown in FIG. 1, the support column 16 of the fixing portion 30 penetrates the plate 36 and further penetrates the upper wall 20 of the thermostatic chamber 4 while maintaining airtightness. The upper end of the column 16 is fixed to a bracket 28 fixed to the plate 36. A bottom plate 27 is fixed to the lower end of the column 16. On the bottom plate 27, a lower grip 15 is installed. The upper and lower portions of the material 17 to be tested are held by the upper gripping portion 14 and the lower gripping portion 15, respectively.

  A temperature sensor 18 (temperature detection means) is installed in the vicinity of the upper grip 14 of the support member 13. As the temperature sensor 18, for example, a thermocouple made of chromel and alumel can be used. The temperature information detected by the temperature sensor 18 is input to the personal computer 3 to be described later via the signal line 33 (FIG. 4).

  As shown in FIGS. 2 and 3, a rotary cooling fan 19 for cooling the support member 13 is installed on the upper surface of the plate 36. The cooling fan 19 cools the support member 13 so that the heat in the thermostatic chamber 4 is not transmitted to the load cell 9. When the rotary type cooling fan 19 is employed, the air can be supplied over a wide range, so that the support member 13 can be cooled satisfactorily.

  FIG. 4 is a system diagram of the material testing apparatus 1 of the present invention. A personal computer 3 is provided separately from the test apparatus main body 2. The personal computer 3 includes an input unit 3a, an output unit 3b, a storage unit 3c, a recording unit 3d, and a CPU 3e that executes various calculations.

  The input unit 3a and the output unit 3b are configured by input / output interfaces such as a USB (Universal Serial Bus), RS-232C (serial port), a parallel port, IEEE1394, and a LAN port.

  The storage unit 3c is composed of a main memory including a RAM (DRAM, SRAM, etc.) that can temporarily store the operation value of the CPU 3e. The recording unit 3d is a writable recording device, and includes, for example, a hard disk, various memory cards, a removable disk such as a flexible disk or a magneto-optical disk, and a fixed disk (hard disk).

  In the recording unit 3d, the amount of expansion / contraction of the support member 13 at each set temperature at the time of performing the material test (the amount of expansion / contraction accompanying a temperature change) is recorded. The amount of expansion / contraction of the support member 13 at each set temperature is obtained in advance by experiments. The temperature information detected by the temperature sensor 18 provided on the support member 13 is input to the input unit 3 a of the personal computer 3 through the signal line 33. The CPU 3e outputs the expansion / contraction amount data recorded in the recording unit 3d corresponding to the input temperature information from the output unit 3b to the control mechanism 32 of the test apparatus body 2 via the signal line 34. An arithmetic expression for calculating the expansion / contraction amount of the material 17 is recorded in the recording unit 3d, and the CPU 3e (expansion / contraction amount calculation means) calculates the expansion / contraction amount from the input temperature value and outputs it to the control mechanism 32. May be.

  The control mechanism 32 recognizes the position indicated by the needle 31 with respect to the index 29 from the expansion / contraction amount data received from the personal computer 3, and sets the position to the zero point. That is, the position of the scale itself of the indicator 29 is shifted so that the position pointed to by the needle 31 becomes the zero point. After this operation is completed, the material 17 is subjected to a tensile test (breaking and creep test) and a compression test. Alternatively, after the test, the actual measurement data can be corrected with the expansion / contraction amount data to obtain a measurement value.

  The expansion / contraction amount data for each set temperature of the support member 13 is collected in advance by experiments and recorded in the recording unit 3d of the personal computer 3. The current expansion / contraction amount of the support member 13 can be grasped from the expansion / contraction amount data recorded in the recording unit 3 d and the temperature value detected by the temperature sensor 18. Further, by transmitting expansion / contraction amount data from the personal computer 3 to the control mechanism 32, it is possible to automatically correct the displacement of the needle 31 with respect to the index 29 due to the expansion / contraction of the support member 13.

  In the material testing apparatus 1 of the present invention configured as described above, the material 17 is disposed in the thermostat 4 and a test can be performed under a desired set temperature condition. At that time, even if the support member 13 expands and contracts, the amount of expansion and contraction can be corrected in advance before starting the test, so that an extremely precise test result can be obtained.

  In many cases, the temperature sensor 18 is provided for each support member 13 in the above-described example, but the temperature inside the thermostat 4 is uniform. If possible, the temperature sensor 18 may be installed at any one location in the thermostatic chamber 4.

  The constant temperature bath 4 is often set to a positive pressure, and the elastic tube 5 (branches 5 a to 5 d) is disposed around the support member 13, and dry air is supplied from the compressor 24 to the elastic tube 5. Thus, the temperature of the dry air in the elastic tube 5 approaches the gas temperature in the thermostat 4, and even if the dry air in the elastic tube 5 flows into the thermostat 4, the environment in the thermostat 4 is almost the same. It does not change. When the material test is performed with the humidity changed, the elastic tube 5 is provided so that the gas in the thermostatic chamber 4 does not leak to the outside of the material test apparatus 1 when performing the tensile test. The material test can be performed without changing the humidity environment.

  In the material testing apparatus 1 configured as described above, precise test results are obtained in consideration of the amount of expansion / contraction of the support member 13 from the low temperature range (about minus 40 ° C.) to the high temperature range (about plus 150 ° C.). be able to.

It is a vertical front view of the test apparatus main body which can implement this invention. FIG. 2 is a side view of a part of the test apparatus main body of FIG. 1 cut vertically. It is a top view of the test apparatus main body of FIG. It is a systematic diagram of the material testing apparatus of this invention. It is detail drawing of an elastic tube. It is a perspective view of an elastic tube. It is a front view of the modification of an elastic tube.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Material test apparatus 2 Test apparatus main body 3 Personal computer 3d Recording part (recording means)
3e CPU (Expansion / contraction amount calculation means)
4 Constant temperature bath 4a Through hole 4b Groove 5 Elastic tube 6 Post 8 Ball screw 9 Load cell (load detection means)
DESCRIPTION OF SYMBOLS 10 Precision ball screw 12 Connection member 13 Support member 14 Upper holding part 15 Lower holding part 17 Material 18 Temperature sensor (temperature detection means)
19 Rotary cooling fan 20 Upper wall of constant temperature bath 24 Compressor 29 Index 30 Fixing part 31 Needle 32 Control mechanism 35 Hole provided in elastic tube

Claims (4)

In the material testing apparatus that includes a thermostatic chamber and performs a material test in the thermostatic chamber, a temperature detection unit that detects the temperature of the inner portion of the thermostatic chamber of the support member that supports the material and supplies an external force to the material is provided. There is provided an expansion / contraction amount calculating means for deriving an expansion / contraction amount due to a temperature change of the support member from the temperature value detected by the temperature detection means, and the reference position for measuring the length of the material by the amount of the expansion / contraction amount of the support member is corrected. The load detecting means for detecting the load applied to the material is disposed on the outer part of the thermostatic chamber of the support member, the support member is cooled, and the heat in the thermostatic bath is transmitted to the load detecting means. Cooling means for enabling suppression , providing a through-hole through which the support member penetrates the thermostatic bath, and arranging an elastic tube containing gas at a pressure higher than the pressure inside and outside the thermostatic bath in the through-hole, Tube penetrates The adhered closely to the wall, the holes provided in the elastic tube, material testing apparatus characterized by blowing gas in the elastic tube toward the support member from the hole. In the material testing apparatus that includes a thermostatic chamber and performs a material test in the thermostatic chamber, a temperature detection unit that detects the temperature of the inner portion of the thermostatic chamber of the support member that supports the material and supplies an external force to the material is provided. Recording means for recording the temperature value detected by the temperature detection means and the amount of expansion and contraction due to temperature change of the support member at the temperature value is provided, and the recording means corresponding to the temperature value detected by the temperature detection means The reference position for measuring the length of the material corresponding to the amount of expansion and contraction of the support member recorded in the correction is corrected, and a load detection means for detecting a load applied to the material is provided on the outer part of the thermostatic chamber of the support member. arrangement, and the support member is cooled, heat of the thermostatic chamber is provided with a cooling means enabling prevented from being transferred to the load detecting means is provided with a through hole through which the said supporting member to said constant temperature bath An elastic tube containing gas at a pressure higher than the atmospheric pressure inside and outside the thermostatic chamber is disposed in the through hole, the elastic tube is in close contact with the wall surface of the through hole, and a hole is provided in the elastic tube and supported from the hole A material testing apparatus for spraying gas in an elastic tube toward a member .   In the material testing apparatus that includes a thermostatic chamber and performs a material test in the thermostatic chamber, a temperature detection unit that detects the temperature of the inner portion of the thermostatic chamber of the support member that supports the material and supplies an external force to the material is provided. There is provided an expansion / contraction amount calculation means for deriving an expansion / contraction amount due to a temperature change of the support member from the temperature value detected by the temperature detection means, and the reference position for measuring the length of the material is corrected by the amount of expansion / contraction amount of the support member. The thermostatic chamber is provided with a through-hole that allows the support member to pass therethrough, and an elastic tube containing gas at a pressure higher than the pressure inside and outside the thermostatic chamber is disposed in the through-hole, and the elastic tube is in close contact with the wall surface of the through-hole The material testing apparatus is characterized in that a hole is provided in the elastic tube, and gas in the elastic tube is blown toward the support member from the hole.   In the material testing apparatus that includes a thermostatic chamber and performs a material test in the thermostatic chamber, a temperature detection unit that detects the temperature of the inner portion of the thermostatic chamber of the support member that supports the material and supplies an external force to the material is provided. Recording means for recording the temperature value detected by the temperature detection means and the amount of expansion and contraction due to temperature change of the support member at the temperature value is provided, and the recording means corresponding to the temperature value detected by the temperature detection means A reference position for measuring the length of the material corresponding to the amount of expansion / contraction of the support member recorded in the thermostat bath is provided, and a through-hole for penetrating the support member is provided in the thermostatic bath, and the thermostat bath is provided in the through-hole. An elastic tube containing gas having a pressure higher than the internal and external pressure is disposed, the elastic tube is in close contact with the wall surface of the through hole, a hole is provided in the elastic tube, and the elastic tube is elastically directed toward the support member from the hole. Material testing apparatus being characterized in that the blown gas in the tube.

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