KR102668858B1 - Hybrid Leak Inspection Device - Google Patents

Abstract

The present invention relates to a hybrid leak test device that integrates a differential pressure leak test method for micro leak test and a direct pressure leak test method for large leak test into one device,
A hybrid leakage inspection device according to an embodiment of the present invention,
An air injection unit for injecting air; It includes a leakage inspection unit that tests for leakage of the object to be inspected using compressed air generated by compressing the air supplied from the air injection unit. The leakage test unit includes a differential pressure sensor that injects the compressed air into a leak-free standard product and the test object to create an equilibrium state, and then measures the pressure difference between the standard product and the test object to measure the lost pressure; And, a direct pressure sensor that measures the pressure lost by the compressed air injected into the object to be inspected during a preset time.

Description

Hybrid Leak Inspection Device {Hybrid Leak Inspection Device}

The present invention relates to a hybrid leak test device that integrates a differential pressure leak test method for micro leak test and a direct pressure leak test method for large leak test into one device.

Conventionally, when producing products or parts that require leakage prevention, leakage is determined on the production process line to determine whether the product is defective. In particular, sealing of parts using working fluid is a very important element in terms of preventing aging or failure of component parts. For example, if leakage occurs in a finished vehicle with automobile parts using working fluid, the sealing of the vehicle may occur. Problems arise that make driving itself impossible.

Therefore, for automobile parts that use working fluid, leakage tests are performed on the production process line. When liquids such as water are used, problems such as rust may occur before being installed in the engine, etc. , Leakage testing is usually performed using air.

In particular, as the demand for batteries continues to increase due to the expansion of the electric vehicle market, maintaining the confidentiality of the battery package is a very important factor, and the demand for inspection systems that can properly test and judge this is increasing.

Depending on the type, battery package parts have standards that allow for some leakage, or there are cases where leakage standards are loose. In this case, differential pressure testing is not possible and direct pressure type equipment must be separately equipped, requiring space and space for process construction. There is a problem of increasing costs.

Korean Patent No. 10-1468990

The purpose of the present invention is to provide a hybrid leak test device that integrates a differential pressure leak test method for micro leak test and a direct pressure leak test method for large leak test into one device.

A hybrid leakage inspection device according to an embodiment of the present invention,

An air injection unit for injecting air; It includes a leakage inspection unit that tests for leakage of the object to be inspected using compressed air generated by compressing the air supplied from the air injection unit. The leakage test unit includes a differential pressure sensor that injects the compressed air into a leak-free standard product and the test object to create an equilibrium state, and then measures the pressure difference between the standard product and the test object to measure the lost pressure; And, a direct pressure sensor that measures the pressure lost by the compressed air injected into the object to be inspected during a preset time.

In the hybrid leak detection device according to an embodiment of the present invention, the differential pressure sensor includes a diaphragm and measures the difference between two pressures connected to both sides of the diaphragm, one by one, based on the diaphragm, and the direct pressure sensor is a piezoelectric pressure sensor. It may be at least one of a sensor, a resonance-type pressure sensor, a strain gauge-type pressure sensor, and a capacitance-type pressure sensor.

In the hybrid leak detection device according to an embodiment of the present invention, the leak detection unit includes a static pressure unit that compresses the air injected through the air injection unit until it reaches a reference pressure for pressure measurement, and the compression compressed by the static pressure unit. A first flow path for supplying air to the reference product, a second flow path for supplying compressed air from the static pressure machine to the test object, the first flow path and the second flow path are connected, and the differential pressure sensor is installed. a third flow path connecting the first flow path and the second flow path, the direct pressure sensor is installed, a fourth flow path connected in parallel with the third flow path, and a fourth flow path connected to the first flow path and the second flow path. It may include an injection valve installed on each of the reference products and the inspection object to turn on and off the flow of compressed air injected into the test object, and an inspection valve installed on the fourth flow path.

In the hybrid leak testing device according to an embodiment of the present invention, the inspection valve is open while the reference product and the test object are filled with compressed air, and then the standard product and the test object are filled with compressed air. It can be filled and closed when inspection preparations are completed so that the space on the reference product side and the space on the inspection object side are separated from each other.

In the hybrid leak testing device according to an embodiment of the present invention, a first temperature sensor installed inside the housing of the hybrid leak testing device, a second temperature sensor installed on the outer surface of the reference product, and the test object. It may further include a third temperature sensor installed on the external surface, and a pressure deviation correction unit that corrects the pressure deviation depending on the temperature during the leak test based on the temperature values measured by the first to third temperature sensors.

Details of other implementations of various aspects of the present invention are included in the detailed description below.

According to the hybrid leak testing device according to an embodiment of the present invention, the differential pressure leak testing method for micro leak testing and the direct pressure leak testing method for large leak testing can be integrated and implemented into one device.

In addition, since differential pressure and direct pressure can be measured with a single device, there is no need to provide separate equipment for each measurement method, thereby reducing space and cost for process construction.

Figure 1 is a perspective view showing a hybrid leak detection device according to an embodiment of the present invention.
Figure 2 is a cross-sectional view showing a hybrid leak detection device according to an embodiment of the present invention.
Figure 3 is a block diagram showing a leak detection unit of a hybrid leak detection device according to an embodiment of the present invention.
Figure 4 is a flowchart showing the operation process of a hybrid leak detection device according to an embodiment of the present invention.

Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be exemplified and explained in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all transformations, equivalents, and substitutes included in the spirit and technical scope of the present invention.

The terms used in the present invention are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as 'include' or 'have' are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof. Hereinafter, a hybrid type leakage inspection device according to an embodiment of the present invention will be described with reference to the drawings.

Figure 1 is a perspective view showing a hybrid type leak detection device according to an embodiment of the present invention.

Referring to FIG. 1, the housing (H) of the hybrid leak detection device 100 according to an embodiment of the present invention is equipped with an interface unit 101 that can input operating conditions from the outside or visually output the inspection status. ), a pressure gauge 102 that shows whether the object to be inspected is leaking, a connection port 103 to which the object to be tested for leakage is connected, and an exhaust port 104 that discharges compressed air to the outside after completion of the test are formed.

Figure 2 is a cross-sectional view showing a hybrid leak detection device according to an embodiment of the present invention.

Referring to FIG. 2, the hybrid type leak detection device 100 according to an embodiment of the present invention includes an air injection unit 110 and a leak detection unit 120.

The air injection unit 110 includes an inlet 111 that receives external air, a regulator 112 that adjusts the pressure of the introduced air, and a supply tube 113 that supplies pressure-adjusted air to the leak detection unit 120. Includes.

The leakage inspection unit 120 tests the object to be inspected for leaks using compressed air generated by compressing air supplied through the supply tube 113. This will be explained with reference to FIG. 3 .

Figure 3 is a block diagram showing the leakage test unit 120 of the hybrid type leakage test device according to an embodiment of the present invention.

Referring to FIG. 3, the leakage test unit 120 connects the differential pressure sensor 121 and the direct pressure sensor 122 in parallel to enable micro-leakage test and large-leakage test to be performed with one device.

Specifically, the leakage test unit 120 includes a differential pressure sensor 121, a direct pressure sensor 122, a constant pressure regulator 123, a reference product 124, an injection valve 125: 125a, 125b, an inspection valve 126, It may include an orifice 127, a discharge valve 128, a silencer 129, and first to fourth flow paths (L1 to L4). The second flow path L2 is integrally connected to the connection port 103 to which the work to be inspected for leakage is connected. Alternatively, the connection port 103 itself may be part of the second flow path L2. In the following description, the second flow path L2 is described as including the connection port 103.

The differential pressure sensor 121 includes a diaphragm 121a and measures the difference between two pressures connected to each side of the diaphragm, based on the diaphragm 121a. That is, the differential pressure sensor 121 measures the difference between the air pressure filled in the standard product 124 of a certain volume and the air pressure filled in the work.

If there is a leak in the test object (Work), the air filled in the test object (Work) leaks and the pressure decreases, and the diaphragm of the differential pressure sensor 121 moves to the test object where the pressure decreases, and the differential pressure sensor 121 ) can measure the difference in pressure from the amount of movement. Additionally, the amount of leakage of the inspected object can be measured from the pressure difference. The differential pressure sensor 121 may be installed on the third flow path (L3) connecting the first flow path (L1) and the second flow path (L2).

The direct pressure sensor 122 measures the pressure lost for a given period of time after applying pressure to the object (Work). Additionally, the amount of leakage of the test object can be measured from the lost pressure. This direct pressure sensor 122 may be a typical pressure sensor excluding differential pressure sensors, and includes piezoelectric pressure sensors, resonance-type pressure sensors, strain gauge-type pressure sensors, capacitance-type pressure sensors, etc., and is not specifically limited in the present invention. No. The direct pressure sensor 122 may be installed on the fourth flow path (L4) connecting the first flow path (L1) and the second flow path (L2).

At this time, the third flow path (L3) in which the differential pressure sensor 121 is installed and the fourth flow path (L4) in which the direct pressure sensor 122 is installed are connected in parallel.

The pressure regulator 123 compresses the air supplied through the supply tube 113. The pressure regulator 123 compresses the air until it becomes a reference pressure for pressure measurement. The compressed air that has become the standard pressure is injected into the reference product 124 and the object to be inspected through the first flow path L1 and the second flow path L2.

The reference product 124 is a compressed air receiver with a constant volume and no leakage.

The injection valves 125a and 125b are installed on the first flow path L1 and the second flow path L2, respectively, to turn on and off the flow of compressed air injected into the reference product 124 and the test object. . The injection valves 125a and 125b may be blocked when the reference product 124 and the test object are completely filled with compressed air.

The inspection valve 126 is installed on the fourth flow path (L4) where the direct pressure sensor 122 is installed, and is open while the reference product 124 and the work object are filled with compressed air, and then the reference product ( 124) and the test object (Work) are filled with compressed air, and when inspection preparations are completed, they are closed so that the space on the standard product 124 side and the space on the test object (Work) side are separated from each other.

The orifice 127 is installed at the rear end of the injection valve 125b on the second flow path L2. The orifice 127 is an outlet for controlling the flow rate of compressed air supplied through the second flow path L2. The operator observes the operation of the differential pressure sensor 121 while linearly lowering the pressure in the space on the work side using the orifice 127, and if a difference occurs with the preset behavior requirements, Zero Set by the offset. The differential pressure sensor 121 can be calibrated by changing.

When the test is completed, the discharge valve 128 is opened and the compressed air in the leakage test unit 120 is discharged to the outside through the exhaust port 104. At this time, a silencer 129 is installed in the exhaust port 104 to reduce noise generated when compressed air is discharged to the outside.

Next, the operation process of the hybrid leak detection device according to an embodiment of the present invention will be described with reference to FIG. 4. Figure 4 is a flowchart showing the operation process of a hybrid leak detection device according to an embodiment of the present invention.

First, the operator determines the extent of leakage of the object being inspected. (S100) The leakage range of the test object can be determined empirically or statistically depending on the type of test object. Here, the standard for determining fine leakage and large leakage can be based on the case where the leakage pressure is 0.1 bar. Of course, this is only an example and is not limited to this.

1. In case of an object to be inspected where micro-leakage mainly occurs

If it is determined that the object to be inspected mainly experiences micro-leakage, the operator selects micro-leakage testing through the interface unit 101. (S111) The control unit (not shown) of the leakage test device opens both the injection valves 125a and 125b and the inspection valve 126 to inject compressed air into the standard product 124 and the work. . (S112)

Next, when the reference product 124 and the test object (Work) are completely filled with compressed air, the control unit (not shown) closes all the injection valves 125a and 125b and the inspection valve 126. (S113)

Next, after a predetermined time has elapsed, the control unit displays the value measured by the differential pressure sensor 121 through the pressure gauge 102. (S114) At this time, the measured value may be a pressure difference or a value converted from the pressure difference to a leakage amount.

2. In the case of an object to be inspected where large leakage occurs mainly.

If it is determined that the test object is one in which large leakage occurs, the operator selects the large leakage test through the interface unit 101. (S121) The control unit (not shown) of the leakage test device opens the injection valve 125b of the second flow path L2, and opens the injection valve 125a and the inspection valve 126 of the first flow path L1. is closed and compressed air is injected into the work. (S122)

Next, when the test object (Work) is completely filled with compressed air, the control unit (not shown) closes the injection valve 125a of the first flow path L1. (S123)

Next, after a predetermined time has elapsed, the control unit displays the value measured by the direct pressure sensor 122 through the pressure gauge 102. (S124) At this time, the measured value may be a pressure difference or a value converted from the pressure difference to a leakage amount.

3. When the scope of the leak is unknown

If the operator does not know the leakage range of the object to be inspected, the operator selects integrated leakage testing through the interface unit 101. (S131) The control unit (not shown) of the leakage test device opens both the injection valves 125a and 125b and the inspection valve 126 to inject compressed air into the standard product 124 and the work. . (S132)

Next, when the reference product 124 and the test object (Work) are completely filled with compressed air, the control unit (not shown) closes all the injection valves 125a and 125b and the inspection valve 126. (S133)

Next, after a predetermined time has elapsed, the control unit displays either the value measured by the differential pressure sensor 121 or the value measured by the direct pressure sensor 122 through the pressure gauge 102. (S134) At this time, the measured value may be a pressure difference or a value converted from the pressure difference to a leakage amount.

If the object to be inspected has micro-leakage, it can be measured by the differential pressure sensor 121. In this case, the direct pressure sensor 122 may not be able to measure a significant pressure difference value.

In addition, if the object to be inspected has a large leak, the diaphragm of the differential pressure sensor 121 moves as much as possible toward the object to be inspected (Work), thereby exceeding the measurement limit (measurement range) of the differential pressure sensor 121, making measurement impossible. However, it is within the measurement range of the direct pressure sensor 122 and can be measured by the direct pressure sensor 122.

Meanwhile, the compressed air used during the leak test is affected by the temperature at the time of the leak test, so the test results of the leak test unit 120 may have pressure differences depending on the temperature.

Accordingly, the hybrid leak detection device according to an embodiment of the present invention may further include a pressure deviation correction unit (not shown) that corrects the pressure deviation.

In addition, a first temperature sensor (not shown) installed inside the housing (H) of the hybrid leak detection device 100 to calculate the pressure deviation, and a second temperature sensor installed on the outer surface of the reference product 124. (not shown) and a third temperature sensor (not shown) installed on the external surface of the work.

The pressure deviation correction unit corrects the pressure deviation based on the ideal gas equation of state as shown in the following equation.

PV = nRT = (W/M)RT , ρ = PM/RT

Here, P is pressure (atm), V is volume (㎥), n is number of moles (W/M), R is 0.082 (atm, ㎥/kg mole K), W is weight (kg), M is molecular weight, ρ is the density (kg/㎥).

The values measured using the first to third temperature sensors are shown in the following [Table 1].

Standard product (Master) Test object (Work) variable sign note variable sign note Internal temperature of inspection device Tmo,i initial temperature
(1st temperature sensor) outside temperature _T∞ Standard product surface temperature Tms,i Initial temperature (second temperature sensor) test object
surface temperature Ts,i initial temperature
(3rd temperature sensor) volume VMs schedule volume Vs. Vm=Vs=V

The first process of correcting the pressure deviation in the pressure deviation correction unit is as follows.

1) △Tm,i=Tmo,i - Tms,i

△Tm,i ≤ set value

Pm: pressure calculation via Tms,i

2) △Ts,i = T∞ - Ts,i

△Ts,i ≤ set value

Ps: Calculate pressure through Ts,i

3) Repeat measurement 10 times (measurement = constant time/10) at temperature (Ts,i)

Calculate the pressure change △P1 of each reference product and test object through one measurement

△P1 = nR(T1 - Tsi)

Calculate pressure change △P2 of each reference product and test object through two measurements

△P2 = nR(T2 - T1)

. . .

Calculate pressure change △P10 of each reference product and test object through 10 measurements

4) Pressure deviation between each reference product and the test object: Reflected as time variable

Pa,m = △P1,m + △P2,m + ·· + △P10,m

Pa,s = △P1,s + △P2,s + ·· + △P10,s

5) Pressure deviation correction (reflection)

Standard product: Ps,m (corrected pressure value) = Pm (measured value) - Pa,m (pressure deviation)

Test object: Ps,s (corrected pressure value) = Ps (measured value) - Pas (pressure deviation)

The second process of correcting the pressure deviation in the pressure deviation correction unit is as follows.

1) Stabilization of temperature of reference product and test object (Warm_up time)

Temperature check within a certain time standard

2) Measurement of surface temperature Tm and Ts of reference product and test object at a certain time

3) Temperature deviation calculation

△Ts = |Tm - Ts| << Setting value

4) Repeat measurement 10 times (measurement = constant time/10) at temperature (Ts,i)

Calculate pressure change △P1 between reference product and test object through one-time measurement

△P1 = nR(T1 - Tsi)

Calculate pressure change △P2 of reference product and test object through two measurements

△P2 = nR(T2 - T1)

. . .

Calculate pressure change △P10 between reference product and test object through 10 measurements

5) Calculation of pressure difference between reference product and test object: Reflection of time variable

Pa,m = △P1,m + △P2,m + ·· + △P10,m

Pa,s = △P1,s + △P2,s + ·· + △P10,s

6) Pressure deviation correction (reflection)

Standard product: Ps,m (corrected pressure value) = Pm (measured value) - Pa,m (pressure deviation)

Test object: Ps,s (corrected pressure value) = Ps (measured value) - Pas (pressure deviation)

According to the hybrid leak testing device according to an embodiment of the present invention, the differential pressure leak testing method for micro leak testing and the direct pressure leak testing method for large leak testing can be integrated and implemented into one device. .

In addition, since differential pressure and direct pressure can be measured with a single device, there is no need to provide separate equipment for each measurement method, thereby reducing space and cost for process construction.

Above, an embodiment of the present invention has been described, but those skilled in the art can add, change, delete or add components without departing from the spirit of the present invention as set forth in the patent claims. The present invention may be modified and changed in various ways, and this will also be included within the scope of rights of the present invention.

100: Hybrid leak inspection device
101: interface part 102: pressure gauge
103: connection port 104: exhaust port
110: air injection part
111: inlet 112: regulator
113: supply tube
120: Leakage inspection unit
121: differential pressure sensor 122: direct pressure sensor
123: static pressure device 124: standard product
125: injection valve 126: inspection valve
127: Orifice 128: Discharge valve
129: Silencer L1 ~ L4: 1st ~ 4th flow path

Claims (5)

In the hybrid leak detection device,
An air injection unit for injecting air; and
It includes a leakage inspection unit that tests for leakage of the object to be inspected using compressed air generated by compressing the air supplied from the air injection unit,
The leakage inspection unit:
A differential pressure sensor that creates an equilibrium state by injecting the compressed air into a leak-free standard product and the test object, and then measures the pressure loss by measuring the pressure difference between the standard product and the test object;
A direct pressure sensor that measures the pressure lost by the compressed air injected into the object to be inspected during a preset period of time,
A static pressure device that compresses the air injected through the air injection unit until it reaches a reference pressure for pressure measurement;
A first flow path that supplies compressed air compressed in the pressure regulator to the standard product,
a second flow path that supplies compressed air compressed in the static pressure device to the object to be inspected;
A third flow path connecting the first flow path and the second flow path and in which the differential pressure sensor is installed,
A fourth flow path connecting the first flow path and the second flow path, having the direct pressure sensor installed, and connected in parallel with the third flow path,
Injection valves installed on the first flow path and the second flow path respectively to turn on and off the flow of compressed air injected into the reference product and the test object;
Including an inspection valve installed on the fourth flow path,
Hybrid leak detection device.
In claim 1,
The differential pressure sensor includes a diaphragm and measures the difference between two pressures connected to each side of the diaphragm with the diaphragm as the reference,
The direct pressure sensor is at least one of a piezoelectric pressure sensor, a resonance-type pressure sensor, a strain gauge-type pressure sensor, and a capacitance-type pressure sensor.
Hybrid leak detection device.
delete The method of claim 1, wherein the inspection valve,
It is open while the standard product and the test object are filled with compressed air, and when the standard product and the test object are completely filled with compressed air and inspection preparations are completed, it is closed to create a space on the side of the standard product and the test object. A hybrid leak detection device that separates the space on each side from each other.
The method of claim 1, claim 2, or claim 4,
A first temperature sensor installed inside the housing of the hybrid leak testing device, a second temperature sensor installed on the outer surface of the reference product, and a third temperature sensor installed on the outer surface of the test object;
Further comprising a pressure deviation correction unit that corrects the pressure deviation depending on the temperature during the leak test based on the temperature value measured by the first to third temperature sensors,
Hybrid leak detection device.

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