JP6104594B2 - Internal pressure test device - Google Patents

Description

The present invention relates to internal pressure test equipment.

  A uniaxial creep test or an internal pressure creep test is generally used to evaluate the material life of equipment that is loaded with internal pressure at a high temperature.

  The uniaxial creep test is a test in which a round bar or a square bar is held at a high temperature and a tensile stress is applied in the axial direction. In this uniaxial creep test, time-strain data can be continuously acquired. The time-strain data is important data for performing high temperature characteristic evaluation on a predetermined material. However, the uniaxial creep test is difficult to simulate the internal pressure stress of the actual machine.

  On the other hand, the internal pressure creep test is a test in which a lid is welded to both ends of a tube-shaped test piece, held at a high temperature, gas or water vapor is injected into the test piece, and an internal pressure is applied. As this internal pressure creep test, for example, one disclosed in Patent Document 1 is known.

JP-A-2005-003458

  Unlike the uniaxial creep test, the internal pressure creep test can simulate the stress state of the actual machine. However, the internal pressure creep test cannot acquire time-strain data. That is, the test cannot continuously acquire the deformation behavior of the test piece.

  In order to acquire time-strain data in the internal pressure creep test, it is possible to interrupt the test and measure the deformation amount each time. However, such a measurement method has disadvantages such as a limited number of measurements, an increase in test time and cost, and repeated adverse effects on test results due to repeated temperature increases and decreases.

  In the example shown in the above-mentioned Patent Document 1, it is possible to determine when the test piece is broken, but it is impossible to grasp the deformation behavior over time.

  Further, in the internal pressure creep test, when the deformation of the test piece proceeds, the volume in the test piece increases and the internal pressure decreases. At this time, if a mechanism for automatically adding pressure is provided, there is a possibility that over-pressure increase occurs. The occurrence of over-pressurization becomes a factor that makes it difficult to perform the test safely. For this reason, it is often the case that an operator manually handles the pressure drop without providing a mechanism for automatically adding pressure.

  The present invention is for solving the above-described problems, and an object of the present invention is to enable continuous and safe internal pressure creep tests.

In order to achieve the above object, an internal pressure test apparatus according to the present invention includes a furnace capable of maintaining an interior at a predetermined temperature, and a metal that is disposed in the furnace and sealed in a hollow cylindrical shape that is long in the axial direction. A test piece, a pump disposed outside the furnace, for injecting fluid into the test piece, and connected to the test piece so as to maintain a sealed state in the test piece. The pipe is connected to the pump, and is attached to the pipe between the furnace and the pump, so that the fluid flows from the furnace side toward the pump. A check valve for preventing, a pressure gauge attached to the pipe part between the furnace and the check valve, for measuring an internal pressure of the test piece, and a measured value of the pressure gauge A first controller for controlling the driving of the pump, the furnace and the front A drain valve attached to the piping part between the check valve and the opening and closing of the drain valve based on the measured value of the pressure gauge, and the first controller A separate second controller, and a flow meter attached to the pipe section between the check valve and the pump, for measuring the flow rate of the fluid flowed by the pump toward the test piece, And an arithmetic unit that calculates an internal volume of the test piece based on measurement values of the flow meter and the pressure gauge .

  Moreover, the internal pressure test apparatus according to the present invention is a light-transmitting device that is attached to the wall surface of the furnace facing the outer peripheral surface of the test piece and can visually recognize the test piece from the outside of the furnace. A heat-resistant glass and a laser displacement meter disposed outside the heat-resistant glass and measuring the outer diameter of the test piece by irradiating the outer periphery of the test piece with a laser beam can be provided.

  Moreover, the internal pressure test apparatus according to the present invention can be provided with at least one strain gauge attached to the outer periphery of the test piece in the embodiment.

  Moreover, the internal pressure test apparatus according to the present invention is an embodiment, and the test piece can be filled with a plurality of cores formed of aluminum oxide.

  According to the present invention, the internal pressure creep test can be performed continuously and safely.

FIG. 1 is a schematic block diagram of an internal pressure test apparatus according to a first embodiment of the present invention, in which a furnace and a test piece are shown in cross section. FIG. 2 is a schematic block diagram of an internal pressure test apparatus according to a second embodiment of the present invention, in which a furnace and a test piece are shown in cross section. FIG. 3 is a schematic block diagram of an internal pressure test apparatus according to a third embodiment of the present invention, in which a furnace and a test piece are partially shown in cross section.

  Embodiments of an internal pressure test apparatus according to the present invention and an internal pressure test method using the apparatus will be described below with reference to the drawings. The internal pressure test apparatus of this embodiment is an apparatus for performing an internal pressure creep test.

[First Embodiment]
A first embodiment will be described with reference to FIG. FIG. 1 is a schematic block diagram of an internal pressure test apparatus of the present embodiment, and a furnace 1 and a test piece 3 are shown in cross section.

  First, the configuration of the internal pressure test apparatus of this embodiment will be described.

  The internal pressure test apparatus in this example includes a test piece 3, a furnace 1, a pump 5, a main pipe 19, a discharge pipe 23, a check valve 7, a drain valve 13, a flow meter 15, It has a controller, that is, a first controller 11a and a second controller 11b. Further, the internal pressure test apparatus has a calculation unit 17, in this example, a personal computer 17 (hereinafter referred to as PC 17).

  The furnace 1 is a furnace 1 capable of keeping a predetermined temperature constant, and can hold a temperature of about several hundred degrees for a predetermined time.

  The test piece 3 is arranged in the furnace 1 so as to keep a predetermined distance from the inner wall of the furnace 1. The method for supporting the test piece 3 is omitted.

  Although not shown in detail, the test piece 3 includes a hollow cylindrical metal main body 3a and a metal lid 3b that covers both ends of the main body 3a. The main body 3a is a member that is long in the axial direction (left-right direction in FIG. 1). Each lid 3b is fixed to both ends of the main body 3a by welding or the like. Thereby, the inside of the test piece 3 is kept sealed.

  The test piece 3 is filled with a plurality of cores 4. These cores 4 are spherical bodies formed of aluminum oxide.

  The pump 5 is for flowing a fluid into the test piece 3 in the furnace 1, and is disposed outside the furnace 1. The fluid here is vapor.

  The main pipe 19 is connected to one lid 3 b so that one end thereof maintains the sealed state in the test piece 3. The opposite end is connected to the pump 5. At this time, the main pipe 19 is disposed so as to penetrate the furnace 1. The main pipe 19 is configured to have higher strength against the internal pressure than the test piece 3.

  The check valve 7 is attached to the main pipe 19 between the furnace 1 and the pump 5, and prevents the flow of steam (back flow) from the furnace 1 side toward the pump 5.

  The pressure gauge 9 is attached to the main pipe 19 between the furnace 1 and the check valve 7 and measures the internal pressure inside the test piece 3.

  The PC 17 can communicate with the pressure gauge 9 and the first controller 11a by being electrically connected to each other. The PC 17 is configured to read a measurement value of the pressure gauge 9 and transmit a control signal to the first controller 11a based on the measurement value.

  The first controller 11a controls the driving of the pump 5 based on the control signal transmitted from the PC 17.

  A branch portion 21 is formed in the main pipe 19 between the furnace 1 and the check valve 7. The discharge pipe 23 is connected to the branch portion 21 and extends in a predetermined direction.

  The drain valve 13 is attached to the discharge pipe 23. Normally, the closed state is maintained.

The second controller 11b is electrically connected to and can communicate with the pressure gauge 9 and the drain valve 13, respectively. The second controller 11b reads the measured value of the pressure gauge 9, and controls the opening / closing operation of the drain valve 13 based on the measured value.

  For example, when the internal pressure exceeds a predetermined value (over-pressurized state), the second controller 11b controls to open the drain valve 13. Detailed actions will be described later.

  Subsequently, a test method using the internal pressure test apparatus of the present embodiment will be described with reference to FIG.

  First, the procedure until the internal pressure can be measured will be described.

  First, the test piece 3 is fixed in the furnace 1. At this time, the test piece 3 is fixed so as to maintain a predetermined distance from the inner wall of the furnace 1, the core 4 is filled in the test piece 3, and the lid 3b is fixed to the main body 3a to maintain a sealed state.

  Next, the end of the main pipe 19 is connected to one (right side in FIG. 1) lid 3b. At this time, the main pipe 19 passes through the furnace 1. When the main pipe 19 is connected to the lid 3b of the test piece 3, the inside of the test piece 3 is sealed. Thereafter, the inside of the furnace 1 is heated to a predetermined temperature.

  After stabilizing at a predetermined temperature, the pump 5 is driven to flow the steam into the test piece 3. At this time, the flow of steam from the test piece 3 to the pump 5 is prevented by the check valve 7. Here, the internal pressure of the test piece 3 is measured by the pressure gauge 9, and the amount of steam flowing into the test piece 3 is measured by the flow meter 15.

  Next, a procedure for measuring volume expansion over time will be described.

  The pressure gauge 9 monitors the decrease in internal pressure of the test piece 3.

The measured value of the internal pressure of the test piece 3 measured by the pressure gauge 9 is taken into the PC 17. The PC 17 calculates the volume expansion coefficient (ΔV) from the pressure decrease amount (ΔP) based on the acquired measurement value. For example, the volume expansion coefficient is obtained from the amount of decrease in pressure by using the gas state equation shown in Expression (1).
ΔV = Δn · R · T / ΔP (1)

  At this time, T is set to a constant value.

  The test piece 3 is deformed so that the center in the axial direction of the hollow cylindrical main body 3a swells in consideration of the deformation mode in consideration of both-end restraint by welding. As a result, the expansion rate of the outer diameter can be obtained by converting the volume expansion amount into the outer diameter of the main body 3a of the test piece 3. In this example, the calculation of the expansion coefficient of the outer diameter is performed by the PC 17.

  Thereby, the expansion coefficient of the outer diameter can be calculated over time, and as a result, a time-displacement curve can be obtained continuously.

  Moreover, since the vapor | steam which can flow in into the test piece 3 decreases by filling the core 4, the detection sensitivity of a pressure improves. This is because the ratio of the volume expansion amount to the vapor amount inside the test piece 3 is improved. In this example, since the core 4 is formed of aluminum oxide, it is not necessary to consider the volume expansion of the core 4.

  If volume expansion continues to occur, the deformation of the test piece 3 proceeds. As a result, the internal volume of the test piece 3 increases and the internal force decreases. Further, in order to stably perform the internal pressure creep test, it is necessary to keep the internal pressure of the test piece 3 within a specified range.

  The PC 17 determines whether or not the acquired measurement value is lower than the lower limit of the specified range. When it is determined that the pressure is low, the PC 17 transmits a control signal to the effect that the pump 5 is driven and steam flows into the test piece 3 to the first controller 11a. The first controller 11 a that has received the control signal drives the pump 5 to cause the steam to flow into the test piece 3.

  The amount of steam that flows in is measured by the flow meter 15. By measuring the amount of steam that has flowed into the test piece 3, the amount of expansion of the test piece 3, that is, the volume expansion amount can be calculated. The volume expansion amount by the flow meter 15 can make up for the reliability of the volume expansion amount converted by the above-described equation of state.

  Subsequently, a procedure for suppressing over-boosting will be described.

  The second controller 11b determines whether or not the acquired measurement value is higher than the upper limit of the specified range. When it is determined that the pressure is high, that is, when it is determined that the pressure is excessive, the second controller 11b opens the drain valve 13 and discharges the steam into the test piece 3. Thereafter, when the internal pressure falls within the specified range, the drain valve 13 is closed again by the second controller 11b.

  Thereby, rupture of the test piece 3 and the like due to excessive pressure increase can be avoided.

  As can be seen from the above description, according to the present embodiment, the volume expansion can be calculated continuously while maintaining the internal pressure within the specified range, and a time-displacement curve is continuously obtained during the internal pressure creep test. It becomes possible. As a result, it becomes possible to acquire data necessary for high temperature strength characteristic evaluation and analysis in a test close to the actual use conditions.

  Conventionally, the pressure adjustment during the test was manually performed, and thus the pressure fluctuation occurred. However, according to the present embodiment, it is possible to automatically maintain the pressure within a predetermined range while suppressing the fluctuation of the internal pressure. Become.

  As a result, the internal pressure creep test can be continuously and safely performed.

[Second Embodiment]
A second embodiment will be described with reference to FIG. FIG. 2 is a schematic block diagram of the internal pressure test apparatus of the present embodiment, in which the furnace 1 and the test piece 3 are shown in cross section. This embodiment is a modification of the first embodiment (FIG. 1), and the same or similar parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The internal pressure test apparatus of the present embodiment includes two heat resistant glasses, that is, a first heat resistant glass 25a and a second heat resistant glass 25b, and two laser displacement meters, that is, a first laser displacement meter 27a and a second heat displacement glass. Laser displacement meter 27b.

  In the furnace 1, a predetermined position of the wall surface facing the outer peripheral surface of the main body 3 a of the test piece 3 is opened. A first heat-resistant glass 25a is attached so as to close the opening. In addition, a wall surface facing the first heat-resistant glass 25a is also opened. A second heat-resistant glass 25b is attached so as to close the opening.

  Both the first heat-resistant glass 25 a and the second heat-resistant glass 25 b have translucency characteristics, and the inside can be visually recognized from the outside of the furnace 1.

  The first laser displacement meter 27a is disposed outside the furnace 1 at a position where the outer peripheral surface of the main body 3a can be irradiated with laser light via the first heat-resistant glass 25a. The second laser displacement meter 27b is disposed outside the furnace 1 at a position where the outer peripheral surface of the main body 3a can be irradiated with laser light via the second heat-resistant glass 25b.

  The first laser displacement meter 27 a and the second laser displacement meter 27 b measure the displacement of the outer peripheral surface of the test piece 3 by irradiating the outer periphery of the test piece 3 with laser light. This displacement amount becomes the expansion amount of the outer diameter.

  In consideration of the deformation mode of the test piece 3 described in the first embodiment (FIG. 1), the position where the laser beam is irradiated is the central portion in the axial direction of the main body 3a where the deformation is maximum. In this example, the laser beams are arranged so as to be in the same straight line.

  Assuming that the main body 3a of the test piece 3 is deformed into an axial object, the angle formed by the laser beams may be arbitrarily set as long as the position allows the heat resistant glass to pass therethrough.

  As can be seen from the above description, according to the present embodiment, the same effects as those of the first embodiment can be obtained, and the outer diameter can be directly measured.

[Third Embodiment]
A third embodiment will be described with reference to FIG. FIG. 3 is a schematic block diagram of the internal pressure test apparatus of the present embodiment, in which the furnace 1 and the test piece 3 are partially shown in cross section. This embodiment is a modification of the first embodiment (FIG. 1), and the same or similar parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the internal pressure test apparatus of this embodiment, a strain gauge 29 is attached to the outer peripheral surface of the main body 3 a of the test piece 3. In FIG. 3, illustration of wiring and the like of the strain gauge 29 is omitted. It is preferable to use a strain gauge 29 that can be used at high temperatures and at temperatures up to about 950 degrees.

  By detecting the elongation in the circumferential direction by the strain gauge 29, the displacement of the outer diameter can be obtained. The position where the strain gauge 29 is affixed is the central portion in the axial direction of the main body 3a where deformation is maximized in consideration of the deformation mode of the test piece 3 described in the first embodiment (FIG. 1).

  As can be seen from the above description, according to the present embodiment, the same effects as those of the first embodiment can be obtained, and the outer diameter can be directly measured.

[Other Embodiments]
The description of the above embodiment is an example for explaining the present invention, and does not limit the invention described in the claims. Moreover, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim.

  For example, although the 1st controller 11a which drives the pump 5 and the 2nd controller 11b which drives the drain valve 13 are separate bodies, it is not restricted to this. The first controller 11a and the second controller 11b may be a single controller.

  Moreover, although the 2nd controller 11b is comprised so that the measured value of the pressure gauge 9 may be input directly, it is not restricted to this. For example, the second controller 11b may control the opening / closing of the drain valve 13 based on the measured value of the internal pressure read by the PC 17.

  In the first embodiment, the volume expansion coefficient is calculated based on the ideal gas, but the present invention is not limited to this. For example, it is possible to calculate the volume expansion coefficient with higher accuracy by using van der Waals equation of state or the like.

  In the second embodiment, two laser displacement meters are used, but the present invention is not limited to this. One or three or more may be used. Similarly, in the third embodiment, an example in which one strain gauge 29 is attached is described, but the present invention is not limited to this. A plurality of strain gauges 29 may be attached.

  Further, the features of the second embodiment may be combined with the features of the first embodiment. That is, a method for calculating volume expansion from a gas state equation and a method for obtaining a change in outer diameter directly with a laser displacement meter may be combined with each other.

  Similarly, the features of the third embodiment may be combined with the features of the first embodiment. That is, a method of calculating volume expansion from a gas equation of state and a method of obtaining strain on the outer peripheral surface directly by the strain gauge 29 may be combined with each other.

  Furthermore, all the features of the first to third embodiments may be combined with each other.

DESCRIPTION OF SYMBOLS 1 Furnace 3 Test piece 3a Main body 3b Cover 4 Core 5 Pump 7 Check valve 9 Pressure gauge 11a 1st controller 11b 2nd controller 13 Drain valve 15 Flowmeter 17 Calculation part (personal computer, PC)
19 main piping 21 branching portion 23 discharge piping 25a first heat resistant glass 25b second heat resistant glass 27a first laser displacement meter 27b second laser displacement meter 29 strain gauge

Claims (4)

A furnace capable of maintaining the interior at a predetermined temperature;
A metal test piece disposed in the furnace and sealed in a hollow cylindrical shape that is long in the axial direction; and
A pump disposed outside the furnace for injecting fluid into the specimen;
A piping part connected to the test piece so as to maintain a sealed state in the test piece, arranged to penetrate the furnace, and connected to the pump;
A check valve attached to the piping section between the furnace and the pump to prevent the flow of the fluid from the furnace side toward the pump;
A pressure gauge attached to the piping part between the furnace and the check valve for measuring the internal pressure of the test piece;
A first controller for controlling driving of the pump based on a measurement value of the pressure gauge;
A drain valve attached to the piping section between the furnace and the check valve;
A second controller configured to control the opening and closing of the drain valve based on the measured value of the pressure gauge; and a second controller separate from the first controller ;
A flow meter attached to the piping section between the check valve and the pump and measuring the flow rate of the fluid that the pump has flowed toward the test piece;
Based on the measured values of the flow meter and the pressure gauge, a calculation unit that calculates the internal volume of the test piece;
An internal pressure testing device characterized by comprising: A translucent heat-resistant glass attached to the wall surface of the furnace facing the outer peripheral surface of the test piece, and capable of visually recognizing the test piece from the outside of the furnace
A laser displacement meter disposed on the outside of the heat-resistant glass and measuring the outer diameter of the test piece by irradiating the outer periphery of the test piece with a laser beam;
The internal pressure test device according to claim 1, wherein The internal pressure test apparatus according to claim 1, further comprising at least one strain gauge attached to an outer periphery of the test piece. The internal pressure test apparatus according to any one of claims 1 to 3, wherein the test piece is filled with a plurality of cores formed of aluminum oxide .

Images