KR100875646B1 - Pressure fatigue test apparatus for brazing joint copper pipe and pressure fatigue test method using the same - Google Patents

Abstract

The present invention relates to a pressure resistant fatigue test apparatus for brazing jointed copper tubes that can analyze the maximum burst pressure, the effect of the load speed and the fatigue characteristics of the brazed jointed copper tubes.

The present invention supports the test brazing connection copper tube in a long / detachable manner, supplying pressure to be dynamically changed to transfer the fatigue load of the test brazing connection copper tube, and repeatedly performing the process of recovering the supplied hydraulic pressure An operation unit; Set test conditions of the test brazing connection copper tube mounted on the operation unit, and measure the pressure of the hydraulic motor and the pressure between the hydraulic motor and the test brazing connection copper tube after starting the hydraulic motor to act on the test brazing connection copper tube. The operation unit is controlled to supply the hydraulic pressure in a state in which the actual pressure and the preset pressure are matched, and if the pressure at the present time drops 30% from the pressure before 10/1000 seconds, the test brazing connection copper tube is regarded as a rupture. A control unit which terminates the operation of the operation unit; And a display unit configured to display data input through the control unit or a state of the test brazing connection copper tube under test by the operation unit.

Description

Internal pressure fatigue tester for copper brazing joint pipes and method

1 is a perspective view showing a pressure-resistant fatigue test apparatus for a conventional brazing joint copper tube,

Figure 2 is a perspective view showing a pressure-resistant fatigue test apparatus for brazing joint copper tube of the present invention,

3 to 5 is a front view, a side view and a plan view respectively showing the operation unit shown in FIG.

6 is a test mode screen shown through the display unit shown in FIG.

7 is a graph showing a pressure-time setting example of the pressure-resistant fatigue test apparatus for brazing joint copper pipe according to the present invention;

8 is a graph showing a pressure-life curve calculated using the pressure-resistant fatigue test apparatus for brazing joint copper pipe according to the present invention;

9 is a flow chart showing a pressure-resistant fatigue test process for brazing joint copper tube according to the present invention.

* Description of Signs for Main Parts in Drawings *

100: operation unit 110: frame unit

120: test unit 121: housing

123: see-through window 125: first mount coupling

127: second mount coupling

130: hydraulic processing unit 131: solenoid valve block

132: hydraulic motor 133: pressure gauge

134: timer 135: hydraulic input line

136: oil filter 137: fan cooler

138: hydraulic discharge line 140: oil tank

200: control unit 300: display unit

400: switch panel 500: key input unit

The present invention relates to a pressure resistant fatigue test apparatus for brazing jointed copper tubes, and more particularly, to a pressure resistant fatigue test apparatus for brazing jointed copper tubes capable of analyzing the maximum burst pressure, the effect of the load speed and the fatigue characteristics of the brazed jointed copper tubes. .

In general, the brazing method is a method of joining two base materials by infiltrating a molten insertion metal between two base materials to be bonded using capillary action and wettability, and this method does not melt the base material. Since only the insert metal is melted, the thermal effect is smaller than that of welding, and the bonding strength is higher than that of soldering. Because of these characteristics, the brazing method has been applied to a large number of joining refrigerant pipes of electronic appliances, in particular, home appliances such as air conditioners.

However, the brazing method basically has a mechanism such as melting and cooling of the insert metal. Therefore, defects such as incomplete penetration or pinholes exist in the junction area due to the characteristics of the process, and when such defects grow, Leakage of the refrigerant or premature failure of the refrigerant piping occurs.

Conventionally, defects that may occur during copper tube joining by brazing joints and their defects may be analyzed to improve the life and reliability of the brazing joint by analyzing the influence of such defects on the strength and fatigue characteristics of the brazing joint and identifying the cause of failure. In order to evaluate the effect, manufacturers are using the manual hydraulic pressure test apparatus shown in FIG. 1.

The operation of this passive pressure test device is as follows. First, a large amount of hydraulic pressure is initially injected using the left knob 10, and a small amount of hydraulic pressure is injected using the right knob 11 to set a required pressure. When the required pressure is set, the pressure is fixed using a locking knob (not shown). At this time, the user could grasp the pressure acting on the test brazing joint copper tube installed in the test space 13 through the pressure gauge 12 of the upper portion.

However, such a conventional manual pressure test apparatus had the following problems. First, the maximum test pressure was 160 kgf / cm 2, and the bursting pressure of the brazed jointed copper tube used for home air conditioner could not be obtained. Second, since the pressure was applied manually, it was not possible to evaluate the influence of the loading speed on all materials, that is, various materials of different types. Third, since home air conditioners are used for a long time, the pressure caused by refrigerant inside the pipe is subject to fatigue loads caused by repeated high and low pressures, but the manual pressure test apparatus used by existing home appliances companies is not able to test for such fatigue loads. Originally impossible.

The present inventors came to develop a pressure resistant fatigue test apparatus for brazing joint copper tube according to the present invention in order to improve the disadvantages of the conventional manual hydraulic pressure test apparatus and to develop a technology that can accurately grasp the reliability of the brazing joint.

An object of the present invention for solving the above problems is to provide a pressure resistant fatigue test apparatus for brazing jointed copper tube that can analyze the maximum burst pressure, the effect of the load speed and the fatigue characteristics of the brazed jointed copper tube.

In order to achieve the above object, the present invention supports the test brazing connection copper tube long / detachable, supply pressure to be dynamically changed to transfer the fatigue load of the test brazing connection copper tube, recover the supplied hydraulic pressure An operation unit which repeats the process of performing the operation; Set test conditions of the test brazing connection copper tube mounted on the operation unit, and measure the pressure of the hydraulic motor and the pressure between the hydraulic motor and the test brazing connection copper tube after starting the hydraulic motor to act on the test brazing connection copper tube. The operation unit is controlled to supply the hydraulic pressure in a state in which the actual pressure and the preset pressure are matched, and if the pressure at the present time drops 30% from the pressure before 10/1000 seconds, the test brazing connection copper tube is regarded as a rupture. A control unit which terminates the operation of the operation unit; And a display unit for displaying data input through the control unit or a state of the test brazing connection tube under test by the operation unit. The fatigue pressure test apparatus of the brazing connection tube is provided.

In this case, the operation unit is a test unit for loading and detaching the brazing connection copper tube and to visually check the brazing connection copper tube under test; A hydraulic processing unit for supplying hydraulic pressure to the brazing connecting copper tube of the test unit and draining oil discharged through the brazing connecting copper tube; And an oil tank for storing oil drained from the hydraulic processing unit and again providing oil to the hydraulic processing unit.

The test unit may further include: a housing having a space for accommodating the brazing connection tube; And both sides of the brazing connection copper tube for guiding oil flowing from the oil treatment unit to one side of the brazing connection copper tube and guiding oil discharged to the other side of the brazing connection copper tube to the hydraulic treatment unit. It includes; and the first and second mount coupling for supporting. In this case, the first and second mount couplings detachably support both sides of the brazing connecting copper tube by an internal / external nut and bolt fastening method. The test unit may further include a transparent cover coupled to an opening of one side of the housing to visually identify the brazing connecting copper tube under test from the outside of the housing.

The hydraulic processing unit includes a hydraulic motor for pumping oil from the hydraulic tank to generate the hydraulic pressure required during the test performance; A solenoid valve block for adjusting the hydraulic pressure flowing into the brazing connecting copper tube according to a command transmitted from the controller; A pressure gauge for measuring the pressure applied to the brazing joint copper pipe by the hydraulic motor; Timer for calculating the burst time and fatigue life by measuring the test time taken during the test; A hydraulic input line of which one side is connected to the hydraulic motor and the other side is transferred to the brazing joint copper tube of the test unit; And a hydraulic discharge line guiding the hydraulic hydraulic oil passing through the hydraulic input line to the oil tank and at the same time connected to the solenoid valve block.

The solenoid valve block is installed between the hydraulic input line and the oil tank and discharged from the hydraulic motor so as to receive the necessary pressure correction signal from the controller to match the actual pressure applied to the blade connecting copper pipe with a set pressure. To control the hydraulic pressure.

The hydraulic processing unit is an oil filter for removing impurities of the hydraulic hydraulic oil flowing into the oil tank; And a fan cooler for cooling the hydraulic hydraulic oil whose temperature is increased due to heat generated during the test.

In order to achieve the above object, the present invention is a test unit for supporting the test brazing connection copper tube in the long / detachable and through the inside so as to visually check the test brazing connection copper tube during the test; A hydraulic motor for supplying hydraulic hydraulic oil to the test brazing connecting copper tube mounted to the test unit; A solenoid valve block disposed between the hydraulic motor and the test unit for supplying pressure to be dynamically changed to transfer the fatigue load of the test brazing connection tube; An oil tank connected to the hydraulic motor and for recovering hydraulic pressure discharged through the test brazing connection copper tube; Set test conditions of the test brazing connection copper tube mounted on the operation unit, and measure the pressure of the hydraulic motor and the pressure between the hydraulic motor and the test brazing connection copper tube after starting the hydraulic motor to act on the test brazing connection copper tube. The operation unit is controlled to supply the hydraulic pressure in a state in which the actual pressure and the preset pressure are matched, and if the pressure at the present time drops 30% from the pressure before 10/1000 seconds, the test brazing connection copper tube is regarded as a rupture. A control unit which terminates the operation of the operation unit; And a display unit displaying data input through the control unit or a state of the test brazing connection tube under test, and the like.

Further, the present invention comprises the steps of: (a) mounting a test brazing connecting tube to the fatigue pressure test apparatus to be provided with hydraulic pressure; (b) setting test conditions of the test brazing connection copper tube; (c) measuring the pressure of the hydraulic motor after starting the hydraulic motor; (d) supplying hydraulic pressure to the test brazing connection tube; (e) measuring the pressure between the hydraulic motor and the test brazing connection tube; (f) matching the actual pressure acting on the test brazing connection tube with a predetermined pressure; And (g) considering the test brazing connection tube as a rupture and ending the test when the current time pressure drops by 30% from the pressure before 10/1000 seconds, and ends the test. Through the test method can achieve the above object.

In this case, the rupture criterion for the brazing connection copper tube applied in the step (g)

It is applied by the following equation.

delete

Where P is pressure, t is time, Δt = t _i -t _i-1 = 10 mili-seconds, R _TH = 0.3 (pressure drop ratio).

To provide.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration of the pressure-resistant fatigue test apparatus for brazing joint copper tube according to the present invention in detail.

2 is a perspective view showing a pressure-resistant fatigue test apparatus for brazing joint copper tube according to the present invention, Figures 3 to 5 are a front view, a side view and a plan view respectively showing the operation portion shown in FIG.

Brazed joint copper pressure resistance fatigue test apparatus according to the present invention, as shown in Figure 2, the operation unit 100, the control unit 200, the display unit 300 and the switch panel 400.

The operation unit 100 includes a frame unit 110, a test unit 120, a hydraulic processing unit 130, and an oil tank 140. Hereinafter, the operation unit 100 will be described in detail with reference to FIGS. 3 to 5.

The frame 110 has a test unit 120 is disposed on the upper side, the hydraulic processing unit 130 is disposed in the center, the oil tank 140 is disposed at the lower side, respectively. In this case, the test unit 120 is disposed on the upper side so that the operator can easily mount the test brazing joint copper tube (hereinafter referred to as a “sample”) 10 under test to the test unit 120 and visually grasp it. . However, various arrangements are possible without being limited to such arrangements and depending on the conditions of the workplace or the working conditions of the workers.

The test unit 120 is a portion where an actual test is performed, and includes a housing 121 having an opening formed on one side and a predetermined space portion formed therein, and installed in the housing 121 when performing a test. The transparent cover 123 is coupled to an opening at one side of the housing so that the state of the sample can be visually checked. In addition, first and second mount couplings 125 and 127 are disposed inside the test unit 120 to connect the sample 10, the hydraulic input line 135 and the hydraulic discharge line 138 to be described later. The first and second mount couplings 125 and 127 are internal / external nut and bolt fastening methods to prevent hydraulic leakage between the sample 10 and the hydraulic input line 135 and the hydraulic discharge line 138. It consists of.

The hydraulic processor 130 includes a solenoid valve block 131 for adjusting the pressure of the hydraulic discharge line 138 through on / off of the solenoid valve according to a command transmitted from the controller 200. do. In addition, the hydraulic processing unit 130 is a hydraulic motor 132 for generating the hydraulic pressure required to perform the test, a pressure gauge 133 for measuring the pressure directly applied to the sample 10 by the hydraulic motor 132, and the test A timer 117 is provided for measuring the time required for the test to calculate the rupture time and fatigue life. Furthermore, the hydraulic processing unit 130 may include a hydraulic input line 135 for transmitting the hydraulic pressure applied by the hydraulic motor 132 to the sample 10, an oil filter 136 for removing impurities from the hydraulic oil, and a test. Fan cooler (120) for cooling the hydraulic fluid to be, the hydraulic hydraulic oil is applied to the sample 10 through the hydraulic input line 135, the hydraulic fluid is a line draining the solenoid valve block 131 and the oil tank ( It is provided with a hydraulic discharge line 138 connected to 140.

Oil tank 140 stores the hydraulic oil (hydraulic oil) necessary for performing the test, it is connected to the hydraulic motor 132 and the hydraulic discharge line (138).

On the other hand, the control unit 200 may set the test conditions through the key input unit 500, and controls the overall test process by controlling the hydraulic processing unit 130 through a predetermined test program stored in ROM through the input conditions. can do. In addition, the data obtained during the test process can be stored in RAM to compare the data obtained in real time.

The display unit 300 is connected to the control unit 200, the user can check the data input through the key input unit 500 and display the data obtained through the test process, the user burst pressure, load speed of the sample 10 Can easily evaluate the influence and fatigue characteristics. Since the display unit 300 is of a touch screen type, it is also possible to input the input data through the display unit 300 without using the key input unit 500.

The switch panel 400 arranges safety devices, instruments, indicators, relays, switches, and the like to facilitate the opening and closing of converters and the control and monitoring of devices.

Hereinafter, with reference to the accompanying Figure 9 will be described in sequence the operation of the fatigue pressure test apparatus according to the present invention configured as described above. 9 is a flow chart showing a pressure-resistant fatigue test process for brazing joint copper tube according to the present invention.

First, the blazing joint copper tube (hereinafter referred to as “sample”) 10 is fixed between the first and second mount couplings 125 and 127 disposed in the housing 121 of the test unit 120 (S1).

Then, in order to load the pressure-time characteristic required for the test to the sample 10, predetermined test conditions are set by the test program on the control part 200 via the key input part 500 (S2). In this case, the test conditions are set by the combination of the time on the x-axis and the set pressure on the y-axis, as shown in FIG. 6, and can basically load a trapezoidal pressure-time diagram. In the trapezoidal pressure-time diagram, the controller 200 may freely adjust the pressure rise time, the pressure holding time, and the pressure load time on the x-axis through the key input unit 500 or a pre-stored test program. At the same time, it is possible to test the fatigue characteristics of the sample by simulating the pressure-resistance state acting on the refrigerant pipe of the actual household appliance by adjusting the set pressure.

When the test conditions are determined through the above process, the full test is performed. First, the hydraulic motor 132 is driven to measure the working pressure of the hydraulic pressure generated from the hydraulic motor 132 by the pressure gauge 133 (S3), and supply the hydraulic pressure to the sample 10 through the hydraulic input line 135. (S4). The hydraulic pressure supplied to the sample 10 is drained to the oil tank 140 through the hydraulic discharge line 138.

At this time, before the hydraulic oil is drained into the oil tank 140, the oil filter 136 and the fan cooler 137 are passed through the oil filter 136 and the fan cooler 137 to suppress the impurity removal of the hydraulic oil and the temperature rise. In addition, in order to load the pressure set by the control unit 200 to the sample 10, the pressure measured using the pressure gauge 133 provided between the hydraulic motor 132 and the hydraulic input line 135 is the control unit 200 Is transmitted (S5).

The control unit 200 calculates the difference between the set pressure and the actual pressure by using the pressure data, and in order to correct the error, the solenoid valve block 131 installed between the hydraulic discharge line 138 and the oil tank 140. By transmitting the necessary pressure correction signal, the actual pressure acting on the sample 10 through opening and closing of the solenoid valve coincides with the set pressure (S6).

In addition, when the sample 10 is ruptured by the internal pressure, the control unit 200 is 10/1000 seconds before (time = 10mili-second) based on the present time (time = 0.0second) to evaluate the accurate burst pressure and fatigue life. If the pressure at the present time drops by more than 30%, the test is considered to be a rupture of the sample 10 and the test is stopped (S7). At this time, the burst pressure and the fatigue life are automatically applied. This sets the burst criterion by applying the following equation (1).

Where P is pressure, t is time, Δt = t _i -t _i-1 = 10 mili-seconds, R _TH = 0.3 (pressure drop ratio).

In addition, since such a rupture criterion needs to be changed according to the type of brazing joint copper tube, it is of course possible to configure it so that it can be easily changed in the test software.

Accordingly, in order to evaluate the influence of the pressure or the load speed applied to the sample 10 through the present invention, it is possible to perform the necessary tests by adjusting the pressure rise time and the maximum set pressure (maximum 400kgf / cm 2). In addition, the test time and the burst pressure data, which are measured during the fatigue characteristics and the burst pressure or the load speed test, are shown in Run. It can be automatically saved to 1 and Brk P.

As described above, the present invention overcomes the limitations of the conventional internal pressure test apparatus, which was capable of maintaining only static pressure at a constant pressure level lower than that of the conventional burst pressure, and the burst pressure and the load speed of the brazing joint copper tube under various pressure conditions. This test can be used to test the effects of fatigue and fatigue characteristics, and it is possible to obtain evaluation data that can improve the reliability and reduce the failure rate of household appliances to which a brazing joint is applied.

In the above, the present invention has been illustrated and described by way of specific preferred embodiments, but the present invention is not limited to the above-described embodiments, and the general knowledge in the technical field to which the present invention pertains falls within the scope of the present invention. Various changes and modifications will be possible by those who have the same.

Claims (11)

An operation unit supporting the test brazing connection copper tube in a long / detachable manner, supplying a pressure to be dynamically changed to transfer the fatigue load of the test brazing connection copper tube, and repeatedly recovering the supplied hydraulic pressure; Set test conditions of the test brazing connection copper tube mounted on the operation unit, and measure the pressure of the hydraulic motor and the pressure between the hydraulic motor and the test brazing connection copper tube after starting the hydraulic motor to act on the test brazing connection copper tube. The operation unit is controlled to supply the hydraulic pressure in a state in which the actual pressure and the preset pressure are matched, and if the pressure at the present time drops 30% from the pressure before 10/1000 seconds, the test brazing connection copper tube is regarded as a rupture. A control unit which terminates the operation of the operation unit; And, And a display unit for displaying data input through the control unit or a state of the test brazing connection tube under test by the operation unit. The method of claim 1, wherein the operation unit A test unit for mounting / removing the brazing connection copper tube and visually confirming the brazing connection copper tube under test; A hydraulic processing unit for supplying hydraulic pressure to the brazing connection copper tube of the test unit and draining oil discharged through the brazing connection copper tube; And, And an oil tank for storing oil drained from the hydraulic processing unit and supplying oil to the hydraulic processing unit again. The method of claim 2, wherein the test unit A housing having a space for accommodating the brazing connection tube; And, It is disposed inside the housing to guide the oil flowing from the oil treatment unit to one side of the brazing connection copper tube, and supports both sides of the brazing connection copper tube to guide the oil discharged to the other side of the brazing connection copper tube to the hydraulic treatment unit. The first and second mount coupling to the fatigue pressure test apparatus of the brazing connecting copper pipe comprising a. The fatigue pressure test apparatus of claim 3, wherein the first and second mount couplings detachably support both sides of the brazing connection copper tube by an internal / external nut and bolt coupling method. The method of claim 3, wherein the test unit And a transparent cover coupled to an opening of one side of the housing to visually identify the brazing connection copper tube under test from the outside of the housing. According to claim 2, wherein the hydraulic processing unit A hydraulic motor for pumping oil from the hydraulic tank to generate a hydraulic pressure necessary for performing a test; A solenoid valve block for adjusting the hydraulic pressure flowing into the brazing connecting copper tube according to a command transmitted from the controller; A pressure gauge for measuring the pressure applied to the brazing joint copper pipe by the hydraulic motor; Timer for calculating the burst time and fatigue life by measuring the test time taken during the test; A hydraulic input line of which one side is connected to the hydraulic motor and the other side is transferred to the brazing joint copper tube of the test unit; And, And a hydraulic discharge line guiding the hydraulic hydraulic oil passing through the hydraulic input line to the oil tank and simultaneously connected to the solenoid valve block. The method of claim 6, wherein the solenoid valve block is It is provided between the hydraulic input line and the oil tank to control the hydraulic pressure discharged from the hydraulic motor so as to receive the necessary pressure correction signal from the controller to match the actual pressure acting on the blade connecting copper tube with the set pressure. A fatigue pressure test apparatus for a brazing connection copper tube. The method of claim 6, wherein the hydraulic processing unit An oil filter for removing impurities of the hydraulic hydraulic oil flowing into the oil tank; And, And a fan cooler for cooling the hydraulic oil whose temperature has risen due to heat generated during the test. A test unit for supporting the test brazing connection tube in a long / detachable manner and projecting the inside to visually check the test brazing connection tube in a test; A hydraulic motor for supplying hydraulic hydraulic oil to the test brazing connecting copper tube mounted to the test unit; A solenoid valve block disposed between the hydraulic motor and the test unit for supplying pressure to be dynamically changed to transfer the fatigue load of the test brazing connection tube; An oil tank connected to the hydraulic motor and for recovering hydraulic pressure discharged through the test brazing connection copper tube; Set the test conditions of the test brazing connection tube mounted on the operation unit, measure the pressure of the hydraulic motor and the pressure between the hydraulic motor and the test brazing connection tube after starting the hydraulic motor to the test brazing connection tube. The operation unit is controlled to supply hydraulic pressure in a state in which the actual pressure acting and the preset pressure are matched, and when the current time pressure drops by 30% from the pressure before 10/1000 seconds, the test brazing connection tube is regarded as a rupture. A control unit for terminating the operation of the operation unit; And, And a display unit for displaying data input through the control unit or a state of the test brazing connection tube under test by the operation unit. (a) mounting a test brazing tube to the fatigue pressure test apparatus so that hydraulic pressure can be provided; (b) setting test conditions of the test brazing connection copper tube; (c) measuring the pressure of the hydraulic motor after starting the hydraulic motor; (d) supplying hydraulic pressure to the test brazing connection tube; (e) measuring the pressure between the hydraulic motor and the test brazing connection tube; (f) matching the actual pressure acting on the test brazing connection tube with a predetermined pressure; And, (g) considering the test brazing copper tube as a rupture if the pressure at the present time is 30% lower than the pressure before 10/1000 seconds, and ending the test; the test of the brazing copper tube Way. 11. The method of claim 10, wherein the burst criterion is applied to the brazing connection copper tube applied in the step (g) by the following equation. [Equation]

Where P is pressure, t is time, Δt = t _i -t _i-1 = 10 mili-seconds, R _TH = 0.3 (pressure drop ratio).

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