JP2000329638A - Vacuum tester and airtightness inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a light vacuum tester with improved operation property, visibility, and working efficiency when inspecting the airtightness of gas and liquid at a site to be inspected. SOLUTION: A vacuum tester 1 is composed of a box body 11 that has an opening 12 in a shape according to the surface structure of a site to be inspected and forms a sealed space between the surface of the site to be inspected and the inner wall when a demarcation edge for demarcating the shape of the opening 12 is subjected to contact bonding to the site to be inspected, and a mechanism 16 for adjusting the amount of extraction of air for setting the sealed space to a vacuum state. The box body 11 is formed by a transparent acryl plate for visually recognizing the surface of the site to be inspected being positioned at the opening 12 from a different view point or direction, the mechanism 16 for adjusting the amount of extraction of air is provided with a flow-rate adjustment mechanism for roughly or finely adjusting the amount of extraction of air from the sealed space and constantly maintains the vacuum state of the sealed space by operating the flow-rate adjustment mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a lining plate (corrosion-resistant panel) applied to the surface of a concrete tank of a human waste, sewage treatment plant, chemical plant, semiconductor plant, food processing plant, or the like. The present invention relates to a vacuum tester suitable for inspecting whether or not gas and liquid leak at a joint between lining plates.

[0002]

2. Description of the Related Art For example, when the surface of a concrete tank is covered with a lining plate in order to prevent corrosion, it is necessary to take care to prevent gas and liquid from leaking through the lining plate surface and the joint between the lining plates. Conventionally, it has been responded by visually inspecting the airtightness of each lining plate surface and the joint between the lining plates after the lining plate is constructed, or by using a visual inspection and a watering inspection together. But,
With such a simple inspection method, it has been difficult to accurately determine whether or not gas or liquid has leaked. Therefore, recently, it has been attempted to perform the above-mentioned airtightness inspection by using a vacuum tester for inspecting the presence of leakage at the welded joint between the bottom plate and the bottom plate of the oil tank or the welded joint between the bottom plate and the side plate. I have.

FIGS. 8 and 9 are external perspective views of a conventional vacuum tester of this type. FIG. 8 shows a vacuum tester 8 for a flat surface, and FIG. 9 shows a vacuum tester 9 for a corner. These vacuum testers 8 and 9 each have an opening (not shown), and when the edge defining the shape of the opening is pressed against the surface of the test site, the surface of the test site and the inner wall of the vacuum tester 8 and 9 are separated. A frame body 80 forming a sealed space,
90 and an air bleeding mechanism for evacuating the sealed space. The frame main bodies 80 and 90 are made of metal such as aluminum, and inspection windows 81 and 91 made of glass are provided at predetermined portions in the frame main bodies 80 and 90. The venting mechanism includes ejectors 82 and 92 for communicating an intake pump (not shown) with the sealed space, cocks 83 and 93 for adjusting the amount of intake air, vacuum gauges 84 for checking the degree of vacuum in the sealed space, 94.

A vacuum tester 8 having a structure as shown in FIG.
Is a flat joint between the lining plate and the lining plate (part A in the example of FIG. 7), and the corner vacuum tester 9 having a structure as shown in FIG. 9 is formed of a plurality of lining plates joined at a predetermined angle. It will be used for an airtightness inspection of the joint (part B in the example of FIG. 7). The outline of the airtight inspection method in this case is as follows.

[0005] First, soapy water is applied to a test site.
Then, the defining edges are crimped so that the surface of the test site can be seen from the inspection windows 81 and 91 to form a sealed space in the frame main bodies 80 and 90, and ejectors 82 and 92 communicating with the sealed spaces are provided. At the time of inspection, cocks 83, 9
3 is opened, air is sucked from the sealed space by the ejectors 82 and 92, and the pressure in the sealed space is reduced (evacuated). If gas or liquid leaks to the test site in a state where the degree of vacuum exceeds a predetermined value, crab bubbles are generated at the leak site due to a difference in air pressure from the sealed space. Therefore, the airtightness inspection is performed by visually checking whether or not crab bubbles are generated through the inspection windows 81 and 91. After the inspection, the cocks 83 and 93 are closed, a gap is formed in the demarcated edge, air is sent into the sealed space, and the vacuum testers 8 and 9 are removed from the joint, which is the test site.

[0006]

As described above, the vacuum testers 8 and 9 having the structures shown in FIGS.
It was originally developed to check for leakage at the weld joint between the bottom plate and the bottom plate of the oil tank, or to check for leakage at the weld joint between the bottom plate and the side plate. Therefore, when this is used for the airtightness inspection of the lining plate surface and the joint between the lining plates, there are the following inconveniences.

(1) In the conventional vacuum testers 8 and 9, the degree of vacuum at the time of use is determined by the standard JIS-B-850.
According to No. 1 (Structure of Steel Oil Storage Tank), it is specified that the operation is performed at -400 mmHg. Therefore, the vacuum testers 8 and 9 need to have a robust structure as shown in FIGS. For this reason, the weight becomes heavy, and the burden on the operator is large when inspecting many test sites while moving, or when the test sites are located on the ceiling side as shown in FIG. In addition, airtightness inspection of parts such as the part C (two-sided corner), the part D (three-sided corner) and the part E (three-sided corner) in FIG. 7 could not be performed.

(2) Conventional vacuum testers 8, 9 are:
It is mainly used in bright places. Therefore, the inspection window 8
1,91 was good with only one side. However, in an airtightness inspection performed in a concrete tank placed underground, it is necessary to irradiate a light for illumination to a part to be inspected, so that halation appears in the inspection windows 81 and 91 depending on the irradiation angle of the light. , Visibility was sometimes deteriorated.

(3) The lining plate is formed by coating a vinyl ester resin and a glass cloth tape on the surface of a foam of epoxy resin and mortar. If the degree of vacuum is excessively increased in the airtightness inspection, this lining plate is used. Adversely affect For this reason, it is necessary to adjust the degree of vacuum appropriately to keep the degree of vacuum constant. However, the conventional vacuum tester does not have an adjusting mechanism for maintaining the degree of vacuum constant during the inspection (the frame main bodies 80 and 90 and the inspection windows 81 and 91 are robust and adjust the degree of vacuum during the inspection). The need was low). In addition, vacuum gauge 8
Since the pressure gauges 4 and 94 are fixed and set in a fixed viewing direction, it is difficult to read the values of the vacuum gauges 84 and 94 depending on the part to be inspected, and work is hindered by a hose connected to the suction pump. Sometimes it was difficult.

(4) When moving a test site to another site,
It is necessary to release the degree of vacuum in the sealed space to normal pressure (atmospheric pressure). In this case, in the conventional vacuum testers 8 and 9, the cocks 88 and 93 are closed each time, and a gap is formed in the demarcation edge so that air is introduced, so that the working efficiency is not good.

SUMMARY OF THE INVENTION The main object of the present invention is to provide an improved vacuum tester which can solve such conventional inconveniences at once, and can improve the workability in the airtightness inspection. Another object of the present invention is to provide a highly accurate airtightness inspection method using the vacuum tester.

[0012]

SUMMARY OF THE INVENTION A vacuum tester according to the present invention has an opening having a shape corresponding to the surface structure of a portion to be inspected, and a defining edge defining the shape of the opening is crimped to the portion to be inspected. Sometimes it is configured to include a housing that forms a sealed space between the surface of the test site and the inner wall thereof, and a degassing amount adjusting mechanism for evacuating the sealed space. The housing is formed of a visibility member that allows the surface of the test site located at the opening to be viewed from different viewpoints or viewing directions, and the air volume adjustment mechanism coarsely adjusts the air volume from the sealed space. A first flow rate adjusting mechanism for performing fine adjustment, and a second flow rate adjusting mechanism for performing fine adjustment of the degassing amount.
Characterized in that the degree of vacuum in the sealed space is maintained at a constant value by operating these flow rate adjusting mechanisms.

From the viewpoint of enhancing visibility, it is preferable that the entire surface of the housing except for the opening is made of a transparent resin, and from the viewpoint of improving workability, a gripping surface for gripping by hand is formed on the housing. It is desirable to form at least one vacuum breaker hole for releasing the vacuum state of the sealed space on the gripping surface.

[0014] The shape of the housing is a shape that forms a sealed space including a joint portion of a plurality of plate members joined on the same plane or at mutually different angles. Providing an adsorbable shield member on the defining edge of the housing allows airtightness to be easily maintained.

In the vacuum tester of the present invention, the bleeding amount adjusting mechanism has a vacuum gauge for displaying the degree of vacuum in the sealed space according to the bleeding amount by the first and second flow rate adjusting mechanisms. The vacuum gauge is configured so that its display surface can be displaced according to the viewpoint or viewing direction of the inspector.

From the viewpoint of improving workability, the first and second
Is provided with an operation lever for allowing the operator to arbitrarily adjust the amount of ventilation from different intake sources. Each of these operation levers is provided with a mechanism for distinguishing it from other operation levers, for example, coloring. Further, at least the operation lever of the second flow rate adjusting mechanism can be detached from the flow rate adjusting mechanism after the degree of vacuum is adjusted to a constant value. Thus, it is possible to prevent the operator from erroneously changing the position of the operation lever after adjusting the degree of vacuum.

[0017] In the airtightness inspection method of the present invention, a step of applying a surfactant to a surface of a predetermined inspection site to be inspected, and pressing a demarcation edge of the vacuum tester on the surface of the inspection site by pressing. Forming a sealed space in the housing; driving a vacuum volume adjusting mechanism of the vacuum tester to set the degree of vacuum in the sealed space to a predetermined value; and opening the opening while maintaining the degree of vacuum at the predetermined value. And visually recognizing the presence or absence of crab foam on the surface of the test site located at the position (1) through a housing, and after the visual recognition, releasing the vacuum state in the sealed space.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. In this embodiment, when a lining plate is applied to the ceiling surface of a concrete tank having a complicated shape as shown in FIG. 7 made in the ground, when the lining plate surface and the joint portion between the lining plates (FIG. An example of a vacuum tester that is suitable for performing an airtightness inspection of parts A to E) will be described. When the vacuum tester of the present invention is used, an intake pump is required. However, for convenience of explanation, the description of the intake pump will be omitted, and the structure of the vacuum tester will be mainly described.

First, the characteristic structure of the present invention will be described with reference to an example of a vacuum tester 1 (for inspection of a portion A in FIG. 7) for a simple plane whose appearance is shown in FIG. The vacuum tester 1 has a box body 11 on which gripping surfaces 11a and 11b for gripping from both sides with, for example, two hands are formed.

The box body 11 has a hexahedron having an opening 12 on one side and a visibility member on the other five sides capable of visually recognizing the inside from different viewpoints or viewing directions, for example, a box made of a light and transparent acrylic resin plate. -Shaped housing. An adsorbing shield member, for example, an adsorbing rubber 13 is formed outside the flange-shaped defining edge that defines the shape of the opening 12.
When the suction rubber 13 is pressed against the test site (A in FIG. 7), a sealed space is formed between the surface of the test site and the inner wall of the box body 11. Box body 1
The gripping portions 14a and 14b are provided on one gripping surface 11a and 11b, and a vacuum breaker hole 15 is formed on the gripping surface 11a. The vacuum breaker hole 15 is for holding the sealed space in a vacuum state by pressing it during inspection work with a finger, and releasing the finger to release the vacuum state in the sealed space when finishing the inspection. Hand holding part 1
When holding the vacuum breaker hole 4a, it is preferable to form the vacuum breaker hole 15 at a position where the vacuum breaker hole 15 can be pressed by a finger of the hand.

Incidentally, it is possible to omit the gripping portions 14a and 14b, and it is also possible to adopt a structure in which the vacuum breaker hole 15 is closed with a simple removable lid which is easily removable.

The grip surfaces 11a, 11b of the box body 11
Is further provided on the air release amount adjusting mechanism mounting surface 11c adjacent to
A mounting hole 11d for mounting the gas removal amount adjusting mechanism 16 is formed.

The air volume adjusting mechanism 16 adjusts the degree of vacuum in the sealed space inside the box body 11, and as shown in FIG. 2, mounting members 16a, 16a extending from the mounting holes 11d of the box body 11. 16b, the first quick coupler 16
c, the second quick coupler 16d is connected, and the first
A vacuum gauge 16f is attached to the quick coupler 16c via a rotatable attachment member (coupler) 16e so that the display surface can be arbitrarily displaced. A first flow rate adjusting mechanism for performing fine adjustment and a second flow rate adjusting mechanism for performing fine adjustment are attached.

The first flow rate adjusting mechanism includes, for example, a first ball valve 16g provided with an operation lever 16h, a tee (branch pipe) 16i, a third quick coupler 16j, and a connection port connected to an intake pump using a hose. The second flow rate adjusting mechanism includes a second ball valve 161 branched from, for example, a tee (branch pipe) 16i and provided with an operation lever 16m, and an outside air intake port 16n. The first ball valve 16g roughly adjusts the amount of intake air from the sealed space or stops the intake, and the second ball valve 161 adjusts the amount of intake air from outside so that the intake air from the sealed space is reduced. This is for finely adjusting the amount of ventilation toward the pump. Each ball valve 16g, 16l
The operation levers 16h and 16m attached to the
Each operation lever is colored differently (for example, the operation lever 16h is red and the operation lever 16m is green) so that each operation lever can be easily distinguished from the other operation levers. The operating lever 16m of the second ball valve 16l has a mechanism that can be released from the second ball valve 16l when the value of the specified degree of vacuum is determined by adjusting its position. By doing so, the operation lever 16
A change in the value of the degree of vacuum due to displacement of the position of m can be prevented.

The first and second quick couplers 16c, 16
d mainly serves to facilitate removal of the vacuum gauge 16f and each flow rate adjusting mechanism.
6j is mainly a connection port 16k of a hose to an intake pump.
Can be rotated 360 ° to release the hose from being detached and twisted during the inspection work.

The degassing amount adjusting mechanism 16 configured as described above
By using, it is easy to maintain the degree of vacuum inside the box body 11 at a constant value, and workability is improved. It is also possible to finely adjust the intake air amount in consideration of the vacuum resistance of the lining plate. With respect to the vacuum gauge 16f, the display surface can be displaced in a direction in which the inspector can see the conventional fixed type using a rotatable coupler, thereby improving the visibility.

Next, an example of an airtightness inspection method using the vacuum tester 1 will be described. First, a surfactant (eg, a soap solution similar to the conventional method) is applied to the surface of the test site.
Is applied, and the opening edge (adsorption rubber 13) of the vacuum tester 1 is pressed against the surface of the test site to form a sealed space in the box body 11. By pressing the vacuum breaker hole 15 with a finger and adjusting the degassing amount adjusting mechanism 16 to maintain the degree of vacuum in the sealed space at a predetermined value, it is visually confirmed whether or not crab bubbles are generated at the test site. After the inspection, remove the finger from the vacuum breaker hole 15 to release the vacuum state in the sealed space.

As described above, in the vacuum tester 1 according to the present embodiment, the degree of vacuum in the sealed space can be finely adjusted by the degassing amount adjusting mechanism 16, and the degree of vacuum is maintained at least during the inspection time. It will be easier
A vacuum tester 8 having a conventional structure as shown in FIG.
There is no need to make the structure as robust as in 9. For this reason, a light visibility member such as an acrylic resin plate can be used on five of the six surfaces.

Further, since the inspected portion can be visually recognized from any of the five surfaces, it is possible to flexibly cope with a change in the angle of the light or a change in the working condition. The degree of vacuum in the sealed space can also be checked at any time by a rotatable vacuum gauge 16f. When an airtight inspection is performed, the vacuum breaker hole 15 is pressed with a finger, and when the inspection is completed, the finger is released from the vacuum breaker hole 15. Since the vacuum state can be released only by performing the inspection, the inspection work when there are many test sites can be remarkably reduced.

As described above, according to the present invention, since a structure centering on a light visibility member such as an acrylic resin plate is possible, a portion which was conventionally impossible or difficult, particularly, FIG.
A vacuum tester having a structure that facilitates the airtightness inspection of the portions C to E can be realized at low cost. Hereinafter, with reference to FIG. 3 to FIG. 6, another example of the structure of the vacuum tester in a state in which the air removal amount adjusting mechanism 16 is removed will be described in relation to the test site of each part in FIG. With the vacuum tester 1 of FIG. 1 and the following four vacuum testers 3 to 6, airtightness inspection of all parts in FIG. 7 becomes possible.

FIG. 3 is an external perspective view of the corner corner vacuum tester 3 having the portion B in FIG. 7 as a test site. The box body 31 is formed of an integrally formed acrylic resin five-sided transparent plate, and the flange-shaped defining edge and the suction rubber 33 on the outside thereof are adapted to the joining angle of the two-sided lining plate forming the corner. It is fixed to the box main body 31 at the set angle. The side plate of the box main body 31 is provided with a mounting hole 31d for mounting the above-described air volume adjusting mechanism 16 and a vacuum breaker hole 35. When performing the above-described airtightness inspection method, the vacuum tester 3 presses the suction rubber 33 to the inside corner so that a sealed space is formed between the surface of the inside corner and the inner wall of the box body 31. Become.

FIG. 4 is an external perspective view of the corner corner vacuum tester 4 with the portion C in FIG. The box body 31 is an acrylic resin five-sided transparent plate 41 formed integrally, and the shape of the gripping surface is opposite to that shown in FIG. The flange-shaped defining edge and the suction rubber 43 outside the flange-shaped defining edge are fixed to the box body 41 at an angle suitable for the joining angle of the two-sided lining plate forming the protruding corner. The side plate of the box main body 41 is provided with a mounting hole 41d for mounting the above-mentioned air release amount adjusting mechanism 16 and a hole 45 for a vacuum breaker. When performing the above-described airtightness inspection method, the vacuum tester 4 presses the suction rubber 43 to the outside corner so that a sealed space is formed between the surface of the outside corner and the inner wall of the box body 41. Become.

FIG. 5 is an external perspective view of the corner corner vacuum tester 5 having the portion D in FIG. 7 as a test site. In the vacuum testers 8 and 9 having the conventional structure, the airtightness inspection cannot be performed on the test site having such a structure. The box body 51 is an integrally formed acrylic resin four-sided transparent plate 51, and the overall shape is such that the illustrated bottom surface is formed in one corner, and the illustrated rear portion is formed in the other two surfaces. It is adapted. The flange-shaped defining edge and the suction rubber 53 outside the flange-shaped defining edge are fixed to the box body 51 at an angle suitable for the joining angle of the three-sided lining plate forming the corner. In the side plate of the box body 51, a mounting hole 51d for mounting the above-described air release amount adjusting mechanism 16 is provided.
And a hole 55 for a vacuum breaker.
When performing the above-described airtightness inspection method, the vacuum tester 5 presses the suction rubber 53 to the corner so that a sealed space is formed between the surface of the corner and the inner wall of the box body 51. Become.

FIG. 6 is an external perspective view of the corner corner vacuum tester 6 with the portion E in FIG. With respect to the test portion having such a structure, the vacuum testers 8 and 9 having the conventional structure cannot perform the airtightness inspection. The box body 61 is an acrylic resin four-sided transparent plate 61 integrally formed, and the overall shape is such that the illustrated bottom surface is formed on one surface of the protruding corner, and the illustrated rear portion is formed on the other two surfaces of the protruding corner. It is adapted. The flange-shaped defining edge and the suction rubber 63 outside the flange-shaped defining edge are fixed to the box body 61 at an angle suitable for the joining angle of the three-sided lining plate forming the protruding corner. A mounting hole 61d for mounting the above-described air release amount adjusting mechanism 16 is provided on a side plate of the box body 61,
A vacuum breaker hole 65 is provided. The vacuum tester 6 presses the suction rubber 63 to the outer corner when the above-described airtightness inspection method is performed, so that a sealed space is formed between the surface of the outer corner and the inner wall of the box body 61. Become.

As described above, according to the present invention, it is extremely easy to maintain an appropriate degree of vacuum at a constant level, and it is not necessary to emphasize the strength of the tester body as in the prior art. A vacuum tester can be configured around a transparent plate or the like. Therefore, it is easy to form a box main body having a shape corresponding to the surface structure of a test site including an outgoing corner and an ingoing corner, and a lining of a complicated shape in a ceiling portion such as the A to E in FIG. It becomes possible to carry out an airtight inspection at a construction site of a plate with a small amount of labor.

Also, since the air volume adjusting mechanism is detachably attached via a quick coupler, any one of a plurality of vacuum testers having different shapes of the box body according to the surface structure of the portion to be inspected can be used. There is also an effect that it can be flexibly selected and used.

Further, a vacuum breaker hole is provided, and when performing an airtight inspection, the airtightness is maintained instantaneously by holding the finger with a finger to maintain the degree of vacuum in the sealed space and releasing the finger after the inspection is completed. Since the pressure can be returned to the position to be moved to the next portion to be inspected, no time is wasted and a convenient mechanism can be provided.

[0038]

As is clear from the above description, according to the present invention, the degree of vacuum in the sealed space formed by the surface of the test site and the inner wall of the main body is adjusted to an appropriate value to make it constant. Because it is easy to maintain, it can be composed of lightweight materials, and after the airtight inspection is completed, the sealed space can be immediately returned to the atmospheric pressure, realizing a vacuum tester with excellent operability and workability. Can be. In addition, since the sealed space can be visually recognized from different viewpoints and viewing directions, an accurate inspection result can be obtained. Further, since halation does not occur even when the light is irradiated, it is possible to realize an easy-to-work environment.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a vacuum tester according to an embodiment of the present invention.

FIG. 2 is an external view showing a configuration example of a gas removal amount adjusting mechanism according to the embodiment.

FIG. 3 is a diagram showing an example of a box main body of a vacuum tester for a corner having a two-panel configuration.

FIG. 4 is a view showing an example of a box main body of a vacuum tester for an outgoing corner having a two-panel configuration.

FIG. 5 is a diagram showing an example of a box main body of a vacuum tester for a corner having a three-panel configuration.

FIG. 6 is a view showing an example of a box main body of a vacuum tester for a come-out corner having a three-panel configuration.

FIG. 7 is an explanatory view showing a construction state of a lining plate in a concrete tank and a test site.

FIG. 8 is an external perspective view showing a structural example of a conventional flat panel vacuum tester.

FIG. 9 is an external perspective view showing a structural example of a conventional corner vacuum tester.

[Explanation of symbols]

 1, 3, 4, 5, 6, 8, 9 Vacuum tester 11a, 11b Gripping surface 11c Gripping surface 11d Mounting hole 11, 31, 41, 51, 61 Box body 12 Opening 13, 33, 43, 53, 63 Suction Rubber 14a, 14b Gripping portion 15, 35, 45, 55, 65 Vacuum breaker hole 16 Deaeration adjusting mechanism 16a, 16b Mounting member 16c, 16d, 16j Quick coupler 16e Rotatable mounting member (coupler) 16f Vacuum gauge 16h , 16m Operation lever 16g, 16l Ball valve 16i Tee (branch pipe) 16j Third quick coupler 16k Hose connection port 16n Outside air intake port 80,90 Frame body 81,91 Inspection window 82,92 Ejector 83,93 Cock 84,94 Vacuum gauge

Claims (10)

[Claims] An opening having a shape corresponding to the surface structure of a portion to be inspected, and a surface of the portion to be inspected and an inner wall thereof when a delimiting edge for defining the shape of the opening is crimped to the portion to be inspected. And a casing that forms a sealed space, and a degassing amount adjusting mechanism for bringing the sealed space into a vacuum state, wherein the casing is configured such that the surface of the test site located at the opening thereof has a different viewpoint or viewing direction. And a first flow rate adjusting mechanism for coarsely adjusting the amount of air removed from the sealed space, and a fine adjustment of the amount of air removed. A vacuum tester having a second flow rate adjusting mechanism, wherein the vacuum degree in the sealed space is maintained at a constant value by operating these flow rate adjusting mechanisms. 2. The housing according to claim 1, wherein the housing is formed of a transparent resin integrally formed over the entire surface except for the opening, and has a gripping surface for gripping by hand. Vacuum tester. 3. The vacuum tester according to claim 2, wherein at least one vacuum breaker hole for releasing a vacuum state of the sealed space is formed in the gripping surface. 4. The shape of the housing is such that the sealed space is formed including a joint portion of a plurality of plate members joined on the same plane or at different angles from each other. The vacuum tester according to 2 or 3. 5. The vacuum tester according to claim 1, wherein an adsorbing shield member is provided on a defining edge of the housing. 6. The vacuum amount adjusting mechanism includes a vacuum gauge for displaying a degree of vacuum in the sealed space according to the amount of air removed by the first and second flow rate adjusting mechanisms. The vacuum tester according to claim 1, wherein the display surface is configured to be displaceable according to a viewpoint or a viewing direction of the inspector. 7. The first and second flow rate adjusting mechanisms are provided with operation levers for allowing an operator to arbitrarily adjust the amount of air flow from different intake sources. 7. The vacuum tester according to claim 6, wherein the operation lever of the flow rate adjusting mechanism can be separated from the flow rate adjusting mechanism after the degree of vacuum is adjusted to a constant value. 8. The first flow rate adjusting mechanism, the second flow rate adjusting mechanism, and the vacuum gauge are detachably mounted via a mounting member extending from a predetermined portion of the housing and a quick coupler, respectively. The vacuum tester according to claim 6, wherein: 9. A method for inspecting the airtightness of a test site using the vacuum tester according to claim 3, wherein a step of applying a surfactant to the surface of the test site; Crimping a demarcation edge of the vacuum tester to the surface of the device to form a sealed space in the housing; and adjusting the degassing amount adjusting mechanism while pressing the vacuum breaker hole to determine the degree of vacuum in the sealed space. A step of visually confirming the presence or absence of crab foam in the test site through the housing while maintaining the value at a value, and a step of opening the vacuum breaker hole to release the vacuum state in the sealed space. The airtightness inspection method. 10. The airtightness inspection according to claim 9, wherein the housing is irradiated with light to maintain the illuminance in the sealed space at a predetermined value or more, and then visually check for the presence or absence of the crab foam. Method.