JP2000281188A - Liquid filling nozzle and liquid filling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid any defective operation of a check valve caused by adhesion of a highly viscous liquid. SOLUTION: A liquid filling nozzle comprises a hollow nozzle valve body 41 which has a small diameter cylindrical part to constitute an opening part 90 for filling a liquid on a tip portion, and has a liquid inlet to introduce a liquid to be filled, a plug rod 46 which is inserted in the nozzle valve body 41 in an axially movable and liquid-tight manner, has a shape of the tip part advancing into the small diameter cylindrical portion 41a, and has a gas passage 46b opened in the tip inside, a closing means 49 to close the opening part 90 of the nozzle valve body 41 when the tip portion of the plug rod 46 is advanced into the small diameter cylindrical portion 41a, a driving means 49 to drive the plug rod 46 in the axial direction, an opening/closing valve 145 to open/close the gas passage 46b of the plug rod 46 at the tip of the plug rod 46, valve opening/closing drive means 54, 77b to open/close the opening/closing valve 145, and a positive/negative switching means 91 to switch the pressure condition in the gas passage 46b of the plug rod into the positive pressure condition and the negative pressure condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid filling nozzle and a liquid filling method, and more particularly to a liquid filling nozzle and a liquid filling method suitable for filling a filling liquid into an irregular-shaped container.

[0002]

2. Description of the Related Art Various types of filling nozzles for filling a container with a fixed amount of liquid have been proposed and developed. For example, Japanese Patent Application Laid-Open No. 11-35003 discloses a technique in which a check valve that can be switched between negative pressure and positive pressure is used, and air is extracted from the inside of the container by negative pressure and then the liquid is filled. Hereinafter, an outline of such a filling nozzle will be described with reference to FIG.

In FIG. 4, a measuring piston / cylinder 3
Reference numeral 4 sucks the filling liquid from the tank 31 containing the filling liquid via the switching valve 33, and measures and discharges the filling liquid. The filling nozzle 40 guides the filling liquid into the container 1 and fills the same. A plug rod 46 having an air passage 46b is provided at the center thereof so as to be able to move up and down. It has a configuration provided with a check valve 45 that can be switched by pressure. This filling nozzle 40 is connected to the measuring piston
It is connected to a cylinder 34.

When filling the container 1 with the filling liquid using the filling nozzle 40, the mouth of the container 1 is brought into contact with the centering bell 43, and the center of the plug rod 46 is formed at the outer peripheral edge of the mouth of the container 1. Make a delivery. Thereafter, the plug rod 46 is lowered until the distal end of the plug rod 46 enters the small-diameter cylindrical portion 41a of the nozzle valve body, and the opening of the small-diameter cylindrical portion 41a is closed. The air in the container 1 is discharged by setting the provided air passage 46b to a negative pressure.

When the discharge of the air in the container 1 is completed, the air passage 46b is switched to the positive pressure state, and the check valve 45 provided at the tip of the plug rod 46 is closed. Then, the plug rod 46 is moved upward to open the opening of the small-diameter cylindrical portion 41a, and the container 1 is filled with the liquid. After filling the liquid, the plug rod 46 is moved downward to close the opening of the small-diameter cylindrical portion 41 a again, and then the container 1 is separated from the filling nozzle 40. Then, the air passage 46b is set to a negative pressure,
The filling droplet remaining at the opening of the small-diameter cylindrical portion 41a and the tip of the plug rod 46 is sucked. The filling nozzle 40 having such a configuration is used for filling a filling liquid into an irregular-shaped container.

[0006]

In the above-mentioned conventional filling nozzle 40, since the liquid is filled after evacuating the air from the inside of the container 1 by negative pressure, foaming in the filling liquid is suppressed, and as a result, the accuracy of the filling is reduced. Is improved. Further, the liquid does not flow backward from the container 1 to the air passage 46b during filling, and moreover,
By setting the air passage 46b of the plug rod 46 to a negative pressure after the filled container is separated, the filled liquid droplets remaining at the tip of the plug rod 46 and the small-diameter cylindrical portion 41a and the like are sucked, and the container caused by the drooping. 1 can be prevented.

However, when the filling nozzle 40 is applied to filling of a liquid mixed with a high-viscosity liquid or solid,
Since this liquid is sucked into the plug rod 46, there is a problem that the check valve 45 sticks over time and becomes difficult to move. In view of such circumstances, it is an object of the present invention to provide a liquid filling nozzle and a liquid filling method which can avoid a problem caused by sticking of a high viscosity liquid even when applied to filling of a high viscosity liquid. It is in.

[0008]

According to a first aspect of the present invention, a small-diameter cylindrical portion forming an opening portion for filling a liquid is provided at a distal end portion, and
A hollow nozzle valve main body having a liquid inlet for introducing a filling liquid, and a liquid-tightly inserted inside the nozzle valve main body so as to be movable in an axial direction of the nozzle valve main body and enter the small-diameter cylindrical portion; A plug rod having a possible distal end shape and having a gas passage open at the distal end, and closing the opening of the nozzle valve body when the distal end of the plug rod enters the small-diameter cylindrical portion. Closing means, driving means for driving the plug rod in the axial direction, an opening / closing valve for opening / closing a gas passage of the plug rod at the tip of the plug rod, valve opening / closing driving means for opening / closing the opening / closing valve, Positive / negative pressure switching means for switching a pressure state in the gas passage of the plug rod between a positive pressure state and a negative pressure state is provided. According to a second aspect, in the first aspect, a pressure switching means for switching the gas pressure in the positive pressure state between a low pressure and a high pressure is added. In a third aspect based on the first or second aspect, a liquid supply means for supplying a cleaning liquid to the gas passage of the plug rod is added. In a fourth aspect based on any of the first to third aspects, the valve opening / closing drive means is configured to drive the opening / closing valve via a driving force transmitting element interposed in the gas passage. I have. According to a fifth aspect of the present invention, there is provided a hollow nozzle valve body having a small-diameter cylindrical portion forming an opening for liquid filling at a distal end portion and having a liquid inlet for introducing a filling liquid therein, A plug having a distal end shape that is movably inserted in the axial direction of the nozzle valve main body and liquid-tight within the valve main body, has a distal end shape that can enter the small-diameter cylindrical portion, and has a gas passage that opens at the distal end. A rod, closing means for closing the opening of the nozzle valve body when the tip end of the plug rod enters the small-diameter cylindrical portion, driving means for driving the plug rod in the axial direction, and A liquid filling method using a filling nozzle having an on-off valve for opening and closing a gas passage at a tip of the plug rod, wherein the opening of the nozzle body is closed while the opening of the nozzle body is closed. Close to the tip Opening the on-off valve to discharge the air in the container after the gas passage is brought to a negative pressure, and closing the on-off valve after the air in the container is discharged, and closing the gas passage. Applying a positive pressure, opening the opening to start filling the liquid, closing the opening after the filling is completed, and separating the opening of the container from the tip of the opening. Opening the on-off valve to eject gas in the gas passage from the tip of the plug rod, and blowing out the charged droplets remaining at the tip and the opening of the plug rod by the ejected gas. In. In a sixth aspect based on the fifth aspect, in the step of blowing off the filled droplets, the positive pressure gas in the gas passage is switched from a low pressure to a high pressure. In a seventh aspect based on the fifth or sixth aspect, in the step of supplying a cleaning liquid to the gas passage when the on-off valve is closed and blowing off the filled droplets, the cleaning liquid is supplied together with the gas. The plug is ejected from the tip.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A filling nozzle according to the present invention applied to a filling device for filling a fixed amount of a filling liquid into a bag-shaped irregular-shaped container with a plug will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows a filling nozzle 1 according to the present invention.
It is the schematic diagram which showed the structure of the filling device including the cross section of 40. In FIG. 1, a filling nozzle 1 during a liquid filling process is shown.
The location of the 40 plug rod 46 and air valve 145 are shown. FIG. 2 shows the air valve 1 during the air suction process.
It is sectional drawing which shows the position of 45. FIG. 3 is a sectional view taken along line A-A in FIG.
It is an expanded sectional view by a line, and has shown the sectional shape of the air valve 145. In each figure, the same reference numerals are given to the elements having the same shape and the same function as those of the conventional example shown in FIG.

The filling apparatus shown in FIG. 1 includes a plurality of filling nozzles 140 according to the present invention (only one is shown in the figure). In this filling device, the filling tank 3
After the filling liquid filled in 1 flows down to the manifold 32, it is branched by the same number of branch pipes 32a as the filling nozzles 140, and is introduced into the respective switching valves 33 connected to these branch pipes 32. .

The switching valve 33 includes a piston type spool 33b.
Are slidably disposed in a cylinder-shaped valve main body 33c, and are switched by driving the spool 33b in an axial direction by an actuator 33a. The switching valve 33 operates to switch the branch pipe 32a to the liquid passage 34a. That is, the spool 33b is moved to the position indicated by the two-dot chain line. As a result, the filling liquid introduced into the branch pipe 32a is sent to the piston type measuring pump 34, so that the measuring pump 34 sucks the filling liquid and measures and stores a predetermined liquid amount.

Next, the switching valve 33 operates so that the liquid passage 34a is connected to the flexible filling tube 36. That is, the spool 33b is moved to the position shown by the solid line. Then, the measuring pump 34 starts the discharge stroke and sends out the measured filling liquid to the filling nozzle 140 through the flexible filling tube 36. In this embodiment, the air cylinder 35 is used as a drive source of the metering pump 34. However, the pump 34 can be driven by a mechanical drive source such as a crank rotation mechanism and a rotary cam mechanism. .

Next, the filling nozzle 140 will be described. The filling nozzle 140 includes a nozzle valve body 41, a plug rod 46, an air valve 145, an outer cylinder 42, a centering bell 43, a compression spring 44, an upper outer cylinder 51, an air cylinder 53, a cylinder 54, and the like. I have.

The nozzle valve body 41 has a connecting pipe 41c connected to the flexible filling pipe 36 through a half joint 59. The nozzle valve body 41 has a hollow inside, and a small-diameter cylindrical portion 41a having a reduced diameter is formed at a lower end located downstream of the connection pipe 41c. Inside the nozzle valve body 41, a plug rod 46 is vertically movably and liquid-tightly inserted. This plug rod 4
6 forms an air passage 46b along its central axis,
An air valve 145 described later is provided at the lower end, and a cylinder 54 is attached to the upper end.

A piston 77b, which moves up and down by working air, is fitted to the cylinder 54. The rod 77 of the piston 77b is connected to the air passage 4 of the plug rod 46.
6b, and a valve element 48 is fixed to the end thereof. The valve element 48 is disposed coaxially and vertically movable within a hollow valve cylinder 47 screwed to the tip of the plug rod 46.
As shown in FIG. 2, a tapered surface 48a is formed at a lower end of the valve body 48, and a suction hole 47a is formed at a lower end of the valve cylinder 47.

When the valve body 48 moves up and down by raising and lowering the piston 77b, the tapered surface 48a of the valve body 48 comes into contact with and separates from the inner tapered surface of the suction hole 47. That is, the valve element 48 opens and closes the suction hole 47a. Thus, the valve element 48 and the valve cylinder 47 constitute an air valve 145 that opens and closes the suction hole 47a. As shown in FIG. 3, a plurality of grooves 48b forming an air passage are provided along the axial direction on the upper peripheral surface of the valve body 48 that comes into sliding contact with the valve cylinder 47. An O-ring 49 is fitted on the tapered outer peripheral surface of the valve cylinder 47. The O-ring 49 is connected to the plug rod 46.
Abuts on the tapered surface formed inside the lower portion of the nozzle valve body 41 when the nozzle is pushed down.
Is a closing packing when it operates as a liquid valve. When the plug rod 46 is pushed down,
The air valve 145 is inserted into a small-diameter cylindrical portion 41 a formed at the lower end of the nozzle valve main body 41.

An outer cylinder 42 having a diameter larger than the outer diameter of the outer periphery of the lower portion of the nozzle valve body 41 is fixed by a half joint 57, and a centering bell 43 is vertically movably fitted thereto. . The centering bell 43 is constantly urged downward by a compression spring 44 provided between the nozzle valve main body 41 and the outer cylinder 42, and the lowering of the centering bell 43 is prevented by the lower end of the outer cylinder 42 formed in an inner flange shape. Has been prevented.

When the filling nozzle 140 is lowered while the container 1 is set directly below the filling nozzle 140, the mouth of the container 1 comes into contact with the centering bell 43. And
Thereafter, the centering bell 43 is relatively pushed up against the urging force of the compression spring 44.
It is centered by the outer peripheral shoulder of the mouth of the container 1. The centered bell 43 is pushed up as it is,
As a result, the mouth of the container 1 comes into close contact with the tip of the nozzle valve body 41 with high accuracy.

At the upper part of the nozzle valve body 41, a half joint 5
The upper outer cylinder 51 is coaxially connected by 8, and an air cylinder 53 that drives the plug rod 46 up and down is attached to the upper part of the upper outer cylinder 51. The operating rod 53a of the air cylinder 53 is connected to the cylinder 54 fixed to the plug rod 46. The four-way switching valve 62 for operating the air cylinder 53 is interposed between the working air pipe 64 and the pipes 63 and 63a to the air cylinder 53, and the three-way switching valve 82 for operating the cylinder 54 has the above-described operation. It is interposed between the air pipe 64 and the pipe 83 to the cylinder 54. The cylinder 54
The reason why the three-way type is used as the switching valve 82 for operating the valve is that the urging force of the compression spring 78 is used as the upward operating force of the piston 77b of the cylinder 54.

The air passage 46b of the plug rod 46 is connected to a vacuum pipe 74 via an air pipe joint 55, an air pipe 56 and a three-way switching valve 61 screwed to the plug rod 46.
a and the compressed air pipe 92. Vacuum piping 74
a is connected to the ejector 74. The air supplied from the low-pressure air pipe 93 is used as the operating air for the ejector 74. The compressed air pipe 92 is connected to a high-pressure air pipe 94 for supplying clean air and the low-pressure air pipe 933 via a four-way switching valve 91.

The cleaning process is performed only once in one filling cycle of the filling nozzle 140. That is, the air valve 1
Under the condition where the pump 45 is closed, clean water (for example, sterile water, hot water, hot water, etc.) is supplied through the check valve 88 to the metering pump 85.
Sent to As a result, a small amount of clean water is discharged from the metering pump 85, and the clean water passes through the check valve 86, the water pipe 87, the water supply joint 84 attached to the plug rod 46, and the air passage 46b. Via air valve 14
5 is supplied to the upper space. The water is blown out from the air valve 145 together with the clean air at the same time when the air valve 145 is opened to clean the air valve 145 and the opening 90 of the filling nozzle 140. The pipes 63, 63a, 83, 56
And 87 are both flexible tubes.

The nozzle valve body 41 is supported by a support 66 via a flange 41d integrally formed on the upper peripheral surface thereof, and is fixed to the support 66 by a pressing plate 67. The support 66 is attached to elevating means (not shown). Therefore, the filling nozzle 140 can be moved up and down by a predetermined distance at a predetermined position by the elevating means. Hereinafter, a procedure for filling the container 1 with the liquid using the filling nozzle 140 will be described. In the following description, the above-described cleaning step using clean water is omitted.

(1) Lower the filling nozzle 140,
Step of tightly sealing the container port 1 with the lower end of the nozzle valve body 41: As shown in FIG. 2, the plug rod 46 is lowered to the lower end, and the circumference of the air valve 145 provided at the end of the plug rod 46 is reduced. Filling nozzle 140 by face
Block the liquid valve. In this state, the container 1 is filled with the filling nozzle 140.
, And is gripped by the container gripper 2, and then the filling nozzle 140 is lowered. As a result, the guide portion 43a of the centering bell 43 comes into contact with the outer peripheral edge of the mouth of the container 1 to center the filling nozzle 140, and the mouth of the container 1 comes into close contact with the lower end of the nozzle valve body 41. Sealed.

(2) Vacuuming the air in the container 1 (time is, for example, 0.3 sec): The three-way switching valve 61 is switched to connect the air passage 46b of the plug rod 46 to the vacuum pipe 74a of the ejector 74. Thereby, the air in the vacuum pipe 74a is evacuated. At the same time, the switching valve 82 is switched to release the working air of the cylinder 54. By this operation,
Since the rod 77 is pulled up by the repulsive force of the spring 78, the air valve 45 provided at the lower end of the plug rod 46 is provided.
Is opened, and as a result, the air in the bag-shaped irregular-shaped container 1 is sucked out, and the container 1 is reduced to a flat plate shape.

(3) Closing of the air valve 145: The three-way switching valve 82 is switched to the working air supply side to close the air valve 145. At the same time, the three-way switching valve 61 is switched to set the pressure in the air passage 46b of the plug rod 46 to the pressure of the compressed air on the low pressure side.

(4) Filling: The switching valve 62 is switched to cause the air cylinder 53 to retract. As a result, the plug rod 46 rises, and as shown in FIG.
The liquid valve constituted by the lower part of the nozzle valve main body 41 is opened. On the other hand, the measuring pump 34 is operated at the same time, and the measured filling liquid in the pump 34 is supplied to the filling nozzle 140. Thereby, the container 1 is filled with a prescribed amount of the filling liquid from the opening 90 of the filling nozzle 140.

(5) Closing of the liquid valve: The switching valve 62 is switched to extend the air cylinder 53. As a result, the plug rod 46 descends, so that the tip of the air valve 145 is inserted into the opening 90 of the filling nozzle 140 as shown in FIG. That is, the liquid valve is closed.

(6) Lifting of the filling nozzle: The filling nozzle 140 is raised by a nozzle elevating means (not shown), and the lower end of the filling nozzle 140 is separated from the container 1.

(7) Removal of residual filling liquid: After the container 1 is sufficiently separated from the lower end of the filling nozzle 140, the three-way switching valve 82 is operated to the air discharge side to open the air valve 145. Accordingly, the low-pressure air flows through the tip of the plug rod 46 via the air passage 46b, and the charged droplets remaining at the tip are blown off. Subsequently, the four-way switching valve 91 is operated to switch the air sent to the pipe 92 to high-pressure air. Since this high-pressure air is ejected from the air valve 145 through the air passage 46b, the filling droplets remaining at the tip of the plug rod 46 and the lower portion of the filling nozzle 140 are further blown off and cleaned. This cleaning by air is short. At the end of cleaning, first switch the 4-way switching valve,
The air sent to the air passage 46b is switched to low-pressure air, and then the three-way switching valve 82 is switched to the air supply side so that the air valve 14
Close 5.

(8) Container Replacement, Filling Liquid Measurement: After the filled full container is sent out, the empty container 1 is introduced below the filling nozzle 140. On the other hand, the switching valve 33 is switched during the container replacement, and the liquid passage 32 on the side of the filling liquid tank 31 is switched.
a and the liquid passage 34a on the measuring pump 34 side, and the measuring pump 34 is operated to the suction side to fill the measuring pump 334 with a prescribed amount of the filling liquid. Thereafter, the above process cycle is repeated.

[0031]

[Second Embodiment] In the second embodiment, after the step (3) in the first embodiment is completed and before the step (7), that is, in a state where the air valve 145 is closed. , A step of operating the water pump 85 once is provided. When the water pump 85 is operated, a small amount of clean water flows from the upper part of the air passage 46b of the plug rod 46 through the water pipe 87 and the water supply joint 84, and is stored in the air valve 145. Therefore, the step (7)
When the air valve 145 is opened, the clean water flows along the tip of the plug rod 46 together with clean air supplied from above the air passage 46b. When the clean water is used in combination with air, the cleaning of the air valve 145 is further ensured. That is, even in the case where filling of drinking water or the like having a high sugar content and high viscosity is performed in the filling step, the sugar can be removed by washing with clean water. Therefore, according to this second embodiment, the air valve 14
Inconveniences, such as difficulty in moving 5, are avoided.

[0032]

According to the present invention, since the liquid is filled after the air is evacuated from the container by the negative pressure, foaming in the filling liquid can be suppressed, and the filling accuracy can be improved. The liquid does not flow backward from the container to the air discharge pipe.
Also, after the filling is completed, the pressurized gas is sent to the gas passage in the plug rod after the container is separated and is blown out from the on-off valve provided at the tip of the plug rod. The droplets of the filling liquid remaining in the liquid filling opening can be blown off and removed, and as a result, contamination of the container due to drooping can be avoided. Furthermore,
Even when filling a liquid mixed with a high-viscosity liquid or a solid substance, this liquid is not sucked into the plug rod, so that the liquid may adhere to the on-off valve and hinder its movement. Absent. In addition, even if some viscous material sticks to the on-off valve, the on-off valve is forcibly operated by a driving means such as an air cylinder, so that the function of the on-off valve is not impaired. Furthermore, when the washing water is fed into the gas passage in the plug rod, even if the washing water is applied to filling a drinking water having a high sugar content and a high viscosity, the sugar content is washed with the water and surely removed. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a filling device including a cross section of a filling nozzle according to the present invention.

FIG. 2 is a cross-sectional view showing an operation mode of a filling nozzle when air in a container is being sucked.

FIG. 3 is an enlarged sectional view taken along the line AA of FIG. 2;

FIG. 4 is a schematic view showing a configuration of a conventional filling nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Container gripper 31 Filling liquid tank 33 Switching valve 34 Metering pump 36 Flexible filling tube, 41 Nozzle valve main body 41a Small diameter cylindrical part 42 Outer cylinder 43 Centering bell 44 Compression spring 46 Plug rod 46a Air passage 51 Upper outer cylinder 53 Air Cylinder 54 Cylinder 61 3-way switching valve 62 4-way switching valve 77 Rod 77b Piston 82 3-way switching valve 85 Pump 91 4-way switching valve 140 Filling nozzle 145 Air valve

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshikazu Yamada 1F, Takamichi, Iwazuka-cho, Nakamura-ku, Nagoya-shi, Aichi F-term in Nagoya Machinery Works, Mitsubishi Heavy Industries, Ltd. 3E079 AA07 AB06 BB01 BB02 CC01 DD02 DD31 DD44 DE01

Claims (7)

[Claims] 1. A hollow nozzle valve main body having a small-diameter cylindrical portion forming an opening for filling a liquid at a distal end thereof and having a liquid inlet for introducing a filling liquid, and the inside of the nozzle valve main body. A plug rod having a distal end shape which is inserted in the nozzle valve body in the axial direction and is liquid-tight and is capable of entering the small-diameter cylindrical portion, and which has a gas passage opening at the distal end therein, Closing means for closing the opening of the nozzle valve body when the tip end of the plug rod enters the small-diameter cylindrical portion; driving means for driving the plug rod in the axial direction; and a gas passage of the plug rod. An on-off valve that opens and closes at the tip of the plug rod; a valve on-off drive unit that opens and closes the on-off valve; and a positive / negative pressure switch for switching a pressure state in the gas passage of the plug rod between a positive pressure state and a negative pressure state And a liquid filling nozzle. 2. The liquid filling nozzle according to claim 1, further comprising pressure switching means for switching the gas pressure in the positive pressure state between a low pressure and a high pressure. 3. The liquid filling nozzle according to claim 1, wherein liquid supply means for supplying a cleaning liquid to a gas passage of the plug rod is added. 4. The valve according to claim 1, wherein said valve opening / closing driving means drives said opening / closing valve via a driving force transmission element interposed in said gas passage. A liquid filling nozzle according to any one of the above. 5. A hollow nozzle valve body having a small-diameter cylindrical portion forming an opening for filling a liquid at a distal end thereof and having a liquid inlet for introducing a filling liquid therein, and the nozzle valve. A plug rod which is inserted in the main body in a liquid-tight manner movably in the axial direction of the nozzle valve main body, has a tip end shape capable of entering the small-diameter cylindrical portion, and has a gas passage open at the tip end therein. Closing means for closing the opening of the nozzle valve body when the distal end of the plug rod enters the small-diameter cylindrical portion; driving means for driving the plug rod in the axial direction; and gas for the plug rod. A liquid filling method using a filling nozzle having an on-off valve for opening and closing a passage at a tip of the plug rod, wherein the opening of the nozzle body is closed and the mouth of the container is closed at the tip of the opening. Close to Opening the on-off valve to discharge the air in the container after the gas passage is made to have a negative pressure; and closing the on-off valve after the air in the container is discharged, and closing the gas passage. Opening the opening to start filling of the liquid, closing the opening after the filling is completed, and separating the mouth of the container from the tip of the opening. Opening the on-off valve to eject gas in the gas passage from the tip of the plug rod, and blowing out the filled droplets remaining at the tip and opening of the plug rod by the ejected gas. A liquid filling method characterized by the above-mentioned. 6. The liquid filling method according to claim 5, wherein in the step of blowing off the filling droplet, the pressure of the positive pressure gas in the gas passage is switched from a low pressure to a high pressure. 7. A cleaning liquid is supplied to the gas passage when the on-off valve is closed, and the cleaning liquid is ejected from the tip of the plug rod together with the gas in the step of blowing off the filled droplets. The liquid filling method according to claim 5, wherein the liquid is charged.