JPH091644A - Pressurized gas leak inspection device and blow molding machine for molded containers - Google Patents

Abstract

(57) [Summary] [Purpose] Leakage test for pressurized gas in molded containers that is not affected by changes in the original pressure and does not lose sensitivity even in large-capacity molded containers, and does not require zero adjustment. An apparatus and a blow molding machine having the apparatus are provided. [Constitution] The molding container to be inspected is filled with the pressurized gas, and then the compressed gas is switched to a state in which the pressurized gas is supplied through the orifice. Is supplied to the molding container by flowing through the orifice, the differential pressure is read by a level sensor by a manometer connected to the orifice, and a pressurized gas leak inspection device for the molding container that displays the signal with a signal based on the differential pressure exceeding a certain range, and A blow molding machine having this. The manometer is equipped with a scale-equipped float for reading with the level sensor. [Effect] The effect of achieving the above object is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak inspection device for a molded container such as a blow molded product.

[0002]

2. Description of the Related Art A resin molded product such as a bottle for storing chemicals is molded by a so-called blow molding method in which a parison is housed in a mold and air is blown into the molded product. This blow-molded product is inspected for dimensional accuracy at the mouth and neck after molding, and for flaws at the end of the mouth, and a pinhole (a small hole such as a needle) to prevent leakage when the contents are stored. ) Is checked. This inspection is performed on all products, and defective products are removed from the flow of products to be sequentially produced. In order to inspect such a pinhole, FIG.
As shown in FIG. 5, pressure air is injected into a molding container, for example, a pottle 3 via a pressure regulating valve 1 and an electromagnetic valve 2, and the injection is performed by a pressure gauge 4 when the original pressure is, for example, 0.05 in a plastic bottle. The pressure is adjusted by the pressure adjusting valve 1 so that the pressure becomes 0.20 atm, a constant smooth pressure is generated, and this is continued for a certain time by opening the solenoid valve 2 by the timer relay 5 and then the solenoid valve 2 is closed. In general, a device in which a pressure change in the bottle 3 is detected by a pressure digital sensor 6 provided in a pressure injection circuit and displayed on a display device 7 is generally used.

[0003]

In this inspection apparatus, since the pressure digital sensor 5 detects a change in the pressure of the air in the bottle 3, when the original pressure changes, the minimum scale, for example, 0.01 atm. Even if it changes, in the state where the original pressure is high and in the state where the original pressure is low, the former leaks more in the former and less in the latter, and in the measurement within a certain time, the scale is out of the specified range by the former, so that the bottle 3 is Even if it is determined that there is a pinhole that should be rejected, the latter indicates that the scale is displayed within the range, and even if there is a pinhole of the same size, there is a possibility that an error that is not determined as a defective product may occur. There is a problem that the performance changes due to a change in the original pressure. In a large-capacity container such as 20 liters, even if the filled air may leak due to pinholes, the ratio of the leaked amount to the whole is smaller than that of a small container, and the pressure digital pressure The change that appears in the sensor 5 is small, and even if the same amount of gas leaks, the sensitivity of the digital pressure sensor 5 for detecting the same gas becomes lower as the container becomes larger, and there is a problem that it is not suitable for testing a large-capacity container.

[0004] A first object of the present invention is to provide a pressurized gas leak inspection device for a molding container which does not change its performance even if the original pressure of the pressure gas injected into the molding container changes. A second object of the present invention is to provide a pressurized gas leak inspection apparatus for a molded container which does not become less sensitive even when inspecting a large-capacity molded container. A third object of the present invention is to provide a pressurized gas leak inspection apparatus which can perform quick measurement without the need for adjustment of a measurement reference and without any trouble.

In order to achieve the above object, the present invention provides
(1) In a pressurized gas leak inspection device for a molding container, which measures a change in gas pressure of a pressurized gas injected into the molding container in a sealed state and inspects a leakage of the pressure gas in the molding container, the inspection device has an on-off valve. A pressurized gas injection circuit, a pressurized gas leak inspection circuit in which the pressurized gas is supplied to the molding container via a minute flow rate differential pressure sensor having an orifice in parallel with the pressurized gas injection circuit, A liquid column pressure gauge connected to the supply side and discharge side of the pressurized gas of the minute flow rate differential pressure sensor, and a level sensor for reading a liquid level of the supply side or discharge side of the pressurized gas of the liquid column pressure gauge A level sensor moving mechanism for moving the level sensor, and a liquid level detection display device for reading the liquid level after the level sensor has moved and indicating that the amount of movement of the liquid level has exceeded a certain range. Opening the on-off valve, injecting the pressure gas into the molding container, and supplying or discharging the pressurized gas of the liquid column pressure gauge when the gas pressure in the molding container becomes constant. The liquid level is set to a zero point, the level sensor moving mechanism sets an allowable point for moving the level sensor from the zero point by a certain distance corresponding to the leak allowable value of the molding container, closes the on-off valve, and sets the pressurized gas leak. Activate the micro flow rate differential pressure sensor provided in the inspection circuit,
When the movement amount of the liquid level exceeds the certain distance,
It is an object of the present invention to provide a pressurized gas leak inspection device for a molded container, which operates the liquid level detection display device and inspects whether there is a leak of the pressure gas in the molded container. Also, the present invention provides (2) a pressurized gas leak inspection apparatus for a molding container which measures a change in gas pressure of a pressurized gas injected into a molding container in a sealed state and inspects the leakage of the pressure gas in the molding container. The pressurized gas is supplied to the molding container via a pressurized gas injection circuit having an on-off valve and a minute flow rate differential pressure sensor having an orifice in parallel with the pressurized gas injection path. A pressure gas leak inspection circuit, a liquid column pressure gauge connected to the supply side and discharge side of the pressurized gas of the minute flow rate differential pressure sensor, and a liquid on the supply side or discharge side of the pressurized gas of the liquid column pressure gauge A scaled float provided at the upper end of the column, a level sensor for reading each scale level indicator of the scaled float, and a scale level indicator read from the scaled float while the level sensor is stopped as a zero point, the scale being set to zero. With A liquid level detection display device for detecting a distance from the zero point of the scale level display body read by the level sensor after the movement of the funnel, and displaying that the distance exceeds a predetermined range; Open and inject the pressure gas into the molding container, close the on-off valve after the gas pressure in the molding container becomes constant, operate the small flow rate differential pressure sensor provided in the pressurized gas leak inspection circuit,
The detection of the moving distance from the zero point by the movement of the graduated float provided on the supply side or the discharge side of the pressurized gas of the liquid column pressure gauge and the display based on the detected value indicate the pressure gas in the molding container. Pressurized gas leak inspection device for molded containers that inspects for leak defects,
(3) The scale level indicator of the float with scale is equidistant, and the level sensor is a device using a photoelectric tube which reads each of the scale level indicator and converts it into an electric signal, and detects the liquid level. The pressurized gas leak inspection device for a molded container according to the above (2), further comprising a digital counter for transmitting and counting a signal corresponding to each of the scale level display members read by the device using the photoelectric tube,
(4) In a blow molding machine which blow-molds a barison with a movable mold and holds and moves the molding container to a holder which moves in conjunction with the mold, the holder is stopped and the stopped position is set. The present invention provides a blow molding machine using the pressurized gas leak inspection device for a molding container according to any one of the above (1) to (3) as an inspection device for inspecting a pressure gas leak of the molding container.

[0006]

When the pressurized gas leaks from the pinhole of the molding container, the pressurized gas is supplied through the minute flow rate differential pressure sensor provided with the orifice, and the gas flowing through the minute flow rate differential pressure sensor becomes the original pressure. It is hardly affected by the size of the molding container and the size of the molding container, and the leak test of the molding container can be performed without being affected by the original pressure of the gas by measuring the differential pressure of the minute flow rate differential pressure sensor. In addition, if a scaled float is provided on the liquid level of the liquid column pressure gauge, the scale can be read, and the number of scales from the stop after the movement of the scaled float can be read. Thus, the change in gas pressure can be read without the need for zero point adjustment.

[0007]

Next, embodiments of the present invention will be described. The same reference numerals as in FIG. 7 indicate the same components, as shown in FIG.
Flow rate differential pressure sensor 11 consisting of an orifice in parallel with
And the inlet 12a with a lid is provided on the pressure air supply side.
One end of a water column manometer 12 filled with water in a transparent body, for example, a glass U-shaped tube, is connected via a tank 12b having A float 13 with a scale is floated on the upper surface of the water column on the side, and a photoelectric sensor 17 is fixed to the outside of the glass tube with respect to the float 13 with the scale, and a digital counter 18 is connected to the photoelectric sensor 17 and further connected thereto. Is connected to a display device 19 having a lamp 19a. As shown in FIG. 2, the micro flow rate differential pressure sensor 11 has a small flow path 11a on the pressurized air supply side and a large diameter on the discharge side, that is, the flow path 11b on the side connected to the bottle 3. A so-called orifice is formed in which the former is formed on the low pressure side and the latter is formed on the high pressure side.
A tank 12a provided at one end of the water column manometer 12 is connected to the end of the flow passage 11a of 1b, and the other end of the water column manometer 12 is connected to the bottle 3 side of the flow passage 11b. As shown in FIG. 3, the graduated float 13 is a white molded body mainly composed of a polyethylene resin and a white pigment, and has a rectangular flange 1 at both ends of a cylindrical body 13a.
3b, 13b, and a cylindrical body 13a between both end flanges
Are threaded at equal pitches, blue fishing line made of nylon is wound around them, and graduation level lines 13c, 13c... Are formed at equal pitches. It is housed at the other end of the tube and floated on the water surface, and the four inner corners of the flanges 13b, 13b are in contact with the inner wall of the tube so as to move up and down in parallel with the tube axis. The photoelectric sensor 17 is connected to the scale level lines 13c, 1c, 1c of the float 13 with the scale via the U-shaped tube.
3c, as shown in FIG. 4, at the incident angle of the irradiation light from the light source with respect to the graduated float 13, the reflected light from the spot on which the light hits or the graduation level line in the vicinity thereof is detected and photoelectrically converted. It changes and transmits the signal to the digital counter 18. Digital counter 18
.. Receives the signal from one of the scale level lines 13c, 13c... Of the scaled float 13 while stopped, sets the count value to 0 as a zero point, and moves the scaled float. When the scale level line moves up and down, the count value is incremented by 1 by receiving an electric signal based on the reflected light of the scale level line for each pitch, and when the count value is out of a predetermined value, the output signal is displayed. To turn on the lamp 19a. The lamp may be an audible alarm,
Both may be used. The digital counter 18
Can decrease the count value when the scaled float 13 rises, but can increase the count value when it falls.
The liquid level detection display device according to the present invention can be, for example, a device having these digital counters and display devices. In addition, the bottle 3 is hermetically sealed by the bottle sealing device 20 shown in FIG. That is, the bottle sealing device 20 is composed of a cylindrical shaft 20a to which compressed air is supplied, a flange portion 20b, and a gasket packing 20c. The cylindrical shaft 20a for inspecting the dimensional accuracy of the inner diameter of the mouth and neck is inserted into the bottle 3. The end face of the potter 3 is closely contacted with a flange 20b provided on the shaft while leaving the distal end thereof through a gasket packing 20c made of rubber or the like fitted from the distal end thereof and closely adhered to the flange, and the bottle is sealed. Pressurized air is injected.

In such a configuration, the method of use is, for example, when inspecting a plastic bottle, as shown in FIG.
In (2), the pressure regulating valve 1 is adjusted so that the original pressure is 0.05 to 0.20 kg / cm ² , for example, 0.2 kg as indicated by the pressure gauge 4.
/ Cm ² and set the solenoid valve 2 to the timer relay 5
, And pressurized air is injected into the bottle 3.
The predetermined time is determined by using a normal bottle of the same type without a pinhole and measuring the time until the pressure in the bottle 3 becomes constant and the pressure air does not enter to be measured in advance. In this state, the compressed air hardly flows through the minute flow rate differential pressure sensor 11, the scaled float 13 hardly moves, and the photoelectric sensor 17 hits the light beam at the incident angle of the irradiation light or the nearest scale level line 13c. Is read, and the signal is photoelectrically converted to the digital counter 1
8 is transmitted, and thus 0 is set in the digital counter 18, which means that the zero point adjustment is automatically performed. Next, when the solenoid valve 2 is closed by the timer relay 5 after the elapse of the predetermined time, if there is no pinhole in the bottle 3, the pressure air does not flow through the minute flow rate differential pressure sensor 11 and the water column manometer 12 does not operate. , The digital counter 18 remains set to 0, but if there is a pinhole in the bottle 3 and there is a leak of pressurized air, the pressure in the bottle 3 will decrease. And flows into the bottle 3. The water column manometer 12 connected to the minute flow rate differential pressure sensor 11 is operated by the flow of the pressurized air, whereby the graduated float 13 is operated, and the photoelectric sensor 17 hits at or near the position hit by the incident angle of the irradiation light. Scale level line 13c
Is read, and this is photoelectrically converted and transmitted to the digital counter 18. Then, the number of the read scale level lines 13c is counted by the digital counter 18. After a certain time (time previously determined from the measurement results for the standard bottle) has elapsed since the solenoid valve 2 was closed,
When the count value of the digital counter 18 exceeds a predetermined fixed value, an output signal is generated and this is displayed on the display device 1.
9 to turn on the lamp 19a. This means that the bottle 3 has been inspected to have a pinhole that should be rejected. When the measurement is completed, the bottle 3 is removed from the bottle closure 20, and when another bottle is inspected again, the bottle closure 2 is renewed.
0 is attached to the bottle, and the solenoid valve 2 is first opened to inject pressurized air into the bottle as described above. As a result, the pressurized air does not flow through the minute flow rate differential pressure sensor 11, so that the scaled float 13 rises, and when it stops, the digital counter 18 again counts 0, and the measurement is performed in the same manner as described above. .

In this way, the pinhole of the bottle is inspected, but the water in the water column manometer 12 may be reduced during a large number of inspections.
Is displaced, water is poured into the inlet of the tank 12a as appropriate by pushing the container from a plastic container with a flexible tube, for example, and then replenished. In this case, the stop position of the graduated float 13 is stopped. Rises. In either case, the photoelectric sensor 17 reads the position of the scaled float 13 in the stopped state where the incident angle of the irradiation light hits or the nearest scale level line 13c, so that the zero point adjustment is automatically performed. The inspection can be performed as described above without making any adjustments. In such an inspection apparatus, even if the pitch of the scale level line of the scaled float 13 is made as small as 0.5 mm, it can be read separately from its adjacent scale level line.
0.1mm even for a liter plastic bottle
Can be inspected for the presence of pinholes. In the case of this embodiment, the sensitivity does not change even in the case of a large-capacity molded container, it is almost unaffected by the change in the original pressure, does not impair the performance of the apparatus, and does not affect the zero adjustment at the time of measurement. It is not necessary, and the same measurement can be performed even when the water level changes, so the performance of the device does not change.There is no need for zero adjustment when refilling water, and water can be easily supplied from a plastic container with a tube. Supply can be made, and at that time, the measurement can be prevented from being affected, the inspection work can be performed continuously, the work efficiency can be improved, and the measurement accuracy can be prevented.

In the above embodiment, the scaled float 13 is used, but this is not used, and the same reference numerals as those in the other figures denote the same components, as shown in FIG.
With a glass tube 22a and a flexible hose such as a rubber hose 2
2b and a transparent body, for example, a discharge pipe of a glass tank 23, which is connected to the pressure inlet of the tank 23 and the connection pipe 24 on the pressurized gas supply side of the minute flow rate differential pressure sensor 11 The micro flow rate sensor 11 is connected to the micro flow rate sensor 11 by connecting the glass tube 22a and the flexible connection pipe 26 on the pressurized gas discharge side of the micro flow rate differential pressure sensor 11. A screw rod 25 is fixed to the glass tube 22a.
Is fixed to the screw rod 25, and the glass tube 22a and the screw rod 25
And the photoelectric tube device 29 are provided integrally. Screw rod 2
5 is screwed into a screw tube 27 rotatably supported by a bracket 30 fixed separately, and by rotating the screw tube 27, the glass tube 22a, the screw rod 25, and the photoelectric tube device 29 move up and down at the same time. This constitutes a level sensor moving mechanism. With such a mechanism,
By adjusting the photoelectric tube device 29 up and down, the tank 23 can be adjusted.
And the relative height of the water column manometer 22
The position at the time of stop of the position 8 and the optical axis 28a of the photoelectric tube device 29 can be aligned. The position when the water level 28 stops is the zero point. As in the case of FIG. 1, if the pressurized gas is continuously injected into the bottle to be inspected, the bottle 3 in FIG.
Where the internal pressure is almost constant and the water level 28 stops,
That is, the zero point is determined, but by operating the screw cylinder 27, the optical axis 28a is set at a predetermined distance from the zero point corresponding to the water level 28 corresponding to the pressurized gas leak allowable value previously determined for the standard bottle. Set the allowable point to move to the position and fix it. In this state, when the circuit is switched as described above and the minute flow rate differential pressure sensor 11 is operated, when the water level 28 changes due to the leak in the bottle 3, the movement amount of the water level 28 is predetermined from the zero point. When the light falls below the optical axis 28a beyond the predetermined distance, that is, when the presence of water cannot be detected by the optical axis 28a, an abnormal signal is transmitted to the display device in the same manner as in FIG. 1 and the same display is performed. . In this case, a liquid level detection display device having a photoelectric tube device and a display device is configured. With such a level sensor moving mechanism, the water level 28 rises when water is replenished to the tank 23 in the same manner as described above, and the water level 28 lowers when the water evaporates and becomes small. Since the zero point changes when displaced, it is necessary to set the above-mentioned allowable point again, but the setting of the allowable point can be easily adjusted. In addition,
In the case of FIG. 6, the photoelectric tube device 29 has a light emitting side and a light receiving and photoelectric conversion side. In the case of this embodiment, the sensitivity does not change even in the case of a large-capacity molded container, it is almost unaffected by the change in the original pressure, and the performance of the apparatus is not impaired. Optical axis 28 of the phototube
It is necessary to adjust the a to the permissible point of the water column manometer, so-called permissible point adjustment, especially when the water volume is reduced, when the water is replenished. Is the optical axis 28 of the photoelectric device.
Since an error occurs apart from the position a, an operation of setting an allowable point for moving the photoelectric device to match the allowable point with the optical axis 28a is required. In any case of FIGS. 1 and 6, in other cases, a level sensor such as a photoelectric sensor and a liquid level detection display mechanism such as a water level may be provided on the pressurized gas supply side of the minute flow rate differential pressure sensor. In this case, the tank may be provided on the pressurized gas discharge side of the sensor, or may be provided in other cases.

In order to inspect the bottles sequentially in the order of their production, in the case of blow molding, as shown in FIG. 5, the parison 32 is pushed out from the lower end of the cylinder head 31, and the mold mount 33 is moved in synchronization with this. The parison 32 is accommodated in the cavity of the mold 34 which is moved and placed on the parison 32. Next, the mold mount 33 is moved to move the mold 34 directly below the blow pin 35, and the blow pin is driven into the upper end surface of the parison, and compressed air is blown into the parison so that the parison is in close contact with the inner wall of the mold 34 and molded. ,Cooling. At the end of the cooling, the mold 34 is opened, the probe pin 35 is attached to the mold 34, and it is raised together with the bottle 36 of the hanging product. Then, the mold 34 is moved again to the position of the parison 32 extruded from the cylinder head 31. At the same time, the blow pin 35 is lowered and stopped. In synchronization with the movement of these molds and blow pins, the holder 37 was opened and waited in the open state by a cycle signal from the molding machine main body (not shown). It is moved from immediately below to just below the blow pin 35. Next, the bottle 36 is sandwiched by the holder 37 in the same manner as the mold clamping operation of the mold 34, the blow pin 35 is pulled out, and then the bottle 36 is moved to a position immediately below the bottle closure 20.
In synchronization with this, the bottle sealing device 20 is lowered and the cylindrical shaft 2
0a is inserted into the mouth and neck of the bottle 36, and the gasket packing 20c is brought into close contact with the mouth and neck end face by the flange portion 20b. Thereafter, the inspection described with reference to FIG. 1 and the like is performed as described above. At this time, if there is a pinhole in the bottle 36 or if there is a gap between the gasket packing and the end face of the neck of the pottle, air leaks, and the above-described inspection can be performed. It can be known that either of the end face flaws exists. The cylindrical shaft 20a
Since it is possible to make a product that does not fit into a defective product, the inside diameter of the mouth and neck can be inspected.

[0012] The present invention relates to a method for forming a molded article having a mouth and a neck by blow molding a parison with a movable mold, and holding the molded article on a holder which moves in conjunction with the mold. In the pressurized gas leak inspection device for a molded product with a built-in blow molding machine, the holder is stopped, and at this stop position, at least one of the pinhole and the end face of the mouth and neck of the molded product can be inspected. A mouth-and-neck defect inspection section formed into a cylindrical shape that can be inserted thereinto and supplied with pressurized gas, and is fitted to the mouth-and-neck defect inspection section and is in close contact with a collar provided in the mouth-and-neck defect inspection section. And a blow molding machine having a gasket packing in close contact with the mouth and neck end face of the molded product. You can also. In any of the above-mentioned inventions, the “inspection apparatus” can be used as the “inspection method”, and the limiting condition of each configuration described above can be added to all of them.

[0013]

According to the present invention, there is no change in the performance even if the original pressure of the pressure gas injected into the molding container changes, and the pressurization of the molding container does not reduce the sensitivity even in the inspection of a large-capacity molding container. A gas leak inspection device can be provided. In addition, the use of a graduated float and a level sensor for reading it makes it possible to quickly perform measurements without the need for adjustment of measurement standards, and it is possible to perform measurements quickly, with high measurement accuracy and good performance. Can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic explanatory view of a part of the minute flow rate differential pressure sensor.

FIG. 3 is a sectional view and a plan view of the graduated float.

FIG. 4 is an enlarged explanatory view of a part where a float with a scale is installed in a part of the apparatus of the embodiment.

FIG. 5 is a schematic explanatory view of one embodiment of the blow molding machine of the present invention.

FIG. 6 is a schematic explanatory view of a part of another embodiment of the device of the present invention.

FIG. 7 is a schematic explanatory view of a conventional pressurized gas leak inspection device for a molded container.

[Description of sign]

3 Bottle 11 Micro flow rate differential pressure sensor 12, 22 Water column manometer as liquid column pressure gauge 13 Float with scale 13c Scale level line as scale level display 17 Optical sensor as level sensor 18 Part of liquid level detection display 19 Digital display as part of liquid level detection display device 25 Display part as part of liquid level detection display device 25 Partial screw rod of level sensor moving mechanism 27 Partial screw cylinder of level sensor moving mechanism 29 Level sensor, liquid level detection display device Phototube device as part of

Claims (4)

[Claims] 1. A pressurized gas leak inspection device for a molding container for measuring a change in gas pressure of a pressurized gas injected into a molding container in a sealed state and inspecting the leakage of the pressure gas in the molding container, comprising an on-off valve. A circuit for injecting the pressurized gas, a circuit for inspecting a pressurized gas leak in which the pressurized gas is supplied to the molding container via a minute flow rate differential pressure sensor having an orifice in parallel with the circuit for injecting the pressurized gas; A liquid column pressure gauge connected to the supply side and discharge side of the pressurized gas of the minute flow rate differential pressure sensor, and a level for reading the liquid level on the supply side or discharge side of the pressurized gas of the liquid column pressure gauge A sensor, a level sensor moving mechanism for moving the level sensor,
The level sensor has a liquid level detection display device that reads the liquid level after the movement and displays that the amount of movement of the liquid level exceeds a certain range, and opens the on-off valve to discharge the pressure gas. The liquid level of the pressurized gas on the supply or discharge side of the liquid column pressure gauge when the gas pressure in the molding container is constant after being injected into the molding container is set to zero, and the level sensor moving mechanism is used. An allowable point is set to move the level sensor from the zero point by a fixed distance corresponding to the leak allowable value of the molding container, the on-off valve is closed, and the minute flow rate differential pressure sensor provided in the pressurized gas leak inspection circuit is operated. When the amount of movement of the liquid level exceeds the predetermined distance, the molding vessel for operating the liquid level detection display device and inspecting the molding vessel for a defective leak of the pressure gas. Pressurizing gas leakage testing device. 2. A pressurized gas leak inspection device for a molding container for measuring a change in gas pressure of a pressurized gas injected into a molding container in a closed state and inspecting the leakage of the pressure gas in the molding container, comprising an on-off valve. A circuit for injecting the pressurized gas, and a pressurized gas leak inspection circuit in which the pressurized gas is supplied to the molding container via a minute flow rate differential pressure sensor having an orifice in parallel with the path for injecting the pressurized gas. A liquid column pressure gauge connected to the supply side and discharge side of the pressurized gas of the minute flow rate differential pressure sensor; and a liquid column pressure gauge provided at the upper end of the liquid column on the supply side or discharge side of the pressurized gas. A scaled float, a level sensor for reading each scale level indicator of the scaled float, and a scale level indicator read from the scaled float while the level sensor is stopped is set to a zero point to shift the scaled float. It has a liquid level detection device that detects the distance from the zero point of the scale level indicator read by the level sensor after movement and indicates that the distance exceeds a certain range, and opens the on-off valve. The pressure gas into the molding container, the gas pressure in the molding container becomes constant, the on-off valve is closed, and the minute flow rate differential pressure sensor provided in the pressurized gas leak inspection circuit is operated to operate the liquid. Detection of the movement distance from the zero point by the movement of the graduated float provided on the supply side or the discharge side of the pressurized gas of the pillar pressure gauge, and the display based on the detected value, thereby confirming the leakage of the pressure gas in the molding container. A pressurized gas leak inspection device for molded containers that inspects for defects. 3. The scale level indicator of the scaled float is equidistant, and the level sensor is a device using a photoelectric tube which reads each of the scale level indicators and converts it into an electric signal. 3. The pressurized gas leak inspection device for a molded container according to claim 2, wherein the detection display device has a digital counter for transmitting and counting a signal corresponding to each of the scale level display members read by the device using the photoelectric tube. 4. A blow molding machine for blow molding a barison with a movable mold, and holding and moving the molding container in a holder that moves in connection with the mold, stops the holder and stops the operation. A blow molding machine using the pressurized gas leak inspection device for a molding container according to any one of claims 1 to 3, as an inspection device for inspecting a pressure gas leak of the molding container at a position.