JPH0227212B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an apparatus for injecting liquefied gas in a liquid state, and particularly for injecting liquefied gas into a container filled with a non-foaming beverage or general food that is open to the atmosphere, and then sealing the container. In particular, the present invention relates to a liquefied gas metering injection device suitable for metering liquefied gas when manufacturing a liquefied gas sealed container. (Prior art) In recent years, when filling non-sparkling beverages or general foods into thin-walled metal cans, nitrogen gas or other inert gas has been filled in to increase the pressure inside the can in order to prevent the can from deforming or breaking. is being carried out. The method of filling this inert gas is to first dissolve the inert gas in the beverage using a carbonator or the like and then seal the can body, or to fill the can body with the beverage and then liquefy it. A method is known in which active gas is injected and the lid is then sealed. In the former case, in order to dissolve the necessary amount of inert gas into the beverage to increase the internal pressure of the can, it is necessary to cool the beverage to below room temperature and dissolve it under pressure. It is necessary to perform heat treatment, which increases the number of steps and increases costs. On the other hand, the latter method has the advantage that it can be carried out using drinks at room temperature or relatively high temperature after heat sterilization, but on the other hand, the amount of liquefied inert gas injected into each can is extremely small, so it is difficult to use ultra-low temperature. It is important to accurately measure and inject the liquefied inert gas. In particular, when implementing the latter method, the liquefied inert gas is very easy to vaporize, so when injecting the liquefied inert gas from the liquefied inert gas storage container through the feed pipe and the injection nozzle, it is necessary to use ordinary vacuum insulation. With such means, vaporized gas is likely to be generated in the feed pipe, and it is difficult to eject a gas-liquid mixture from the injection nozzle and inject a fixed amount into the can body. Furthermore, since the injection nozzle faces the position where cans filled with beverages at room temperature or at a relatively high temperature after heat sterilization are continuously fed at regular intervals, water vapor in the atmosphere is generated around the nozzle. There was a problem in that the water froze, obstructing the injection of small amounts of liquefied inert gas, and disrupting the continuous operation of filling and sealing cans. For this reason, a quantitative liquefied gas injection device has been proposed in Japanese Patent Application Laid-Open No. 56-109996, but this has problems due to the generation of vaporized gas in the feed pipe, as well as the freezing of water vapor around the injection nozzle. It is aimed at improving the problem. however,
In addition to the above-mentioned problem, in the case of a system in which a certain amount of liquefied inert gas is retained in the device until the liquefied inert gas is injected, the liquefied inert gas must be continuously injected. The pressure of the vaporized gas above the liquid level of the liquefied inert gas in the retention chamber fluctuates due to the amount of retention changed due to the amount of liquefied inert gas in the retention chamber, and the amount of injection from the injection nozzle is not constant, making quantitative micro-injection difficult. Ta. For this reason, even in the above invention, it has been proposed to include a control device for keeping the level of the liquefied inert gas in the retention chamber constant and a control device for keeping the pressure in the retention chamber constant. In order to keep the liquid level of the liquefied inert gas in the retention chamber constant, the liquefied inert gas is replenished by the inflow.
In addition, the conditions in the retention chamber fluctuate due to the flow of liquefied inert gas caused by the jetting from the liquefied inert gas injection nozzle, and this fluctuation changes the dripping amount of liquefied inert gas, resulting in a quantitative trace amount. injection was inhibited. The present invention eliminates such conventional drawbacks and makes it possible to reliably quantitatively and continuously inject a trace amount of liquefied gas, particularly liquefied inert gas such as liquefied nitrogen gas, or active gas such as carbon dioxide gas, at high speed. This provides a gas metering injection device, which includes an insulated liquefied gas retention chamber, an injection nozzle equipped with an on-off valve device connected to the liquefied gas in the chamber and opened and closed by a can body position detector, and a liquefied gas liquid level position detector, a pressure regulator in the chamber, a liquefied gas supply path connecting a position below the surface of the liquefied gas in the chamber and a position below the surface of the liquefied gas in the liquefied gas storage device; a liquefied gas flow mitigation device provided at the inlet of the supply path to the retention chamber;
and a liquefied gas supply control device that supplies liquefied gas in the liquefied gas storage device into the retention chamber according to the detection signal of the position detector and maintains the level of the liquefied gas in the chamber at a predetermined position. Features. A more detailed explanation will be given below with reference to FIGS. 1 and 2 showing an example of the implementation of the present invention. Figure 1 shows a schematic diagram of the implementation equipment.
(1) is an injector for liquefied nitrogen gas (hereinafter referred to as "LN ₂ gas"), which is a liquefied inert gas, (2) is a storage device for LN ₂ gas, and 3 is an injector for injecting LN gas from storage 2 to injector 1. This is a supply control device that controls the supply amount of _two gases. The injector 1 has an LN ₂ gas retention chamber 4 as shown in detail in the second diagram.
The retention chamber 4 is surrounded by a vacuum insulation chamber 5, which opens below the LN ₂ gas liquid level in the chamber.
It is connected to the reservoir 2 by an LN ₂ gas supply line 6 . The bottom of the retention chamber 4 is equipped with an injection nozzle 7 for discharging the retained LN ₂ gas and an on-off valve device 8 for opening and closing the nozzle 7, while maintaining the nozzle 7 at a low temperature and preventing moisture in the air from freezing. In order to prevent this, the other end of the vaporized gas discharge pipe 9 connected to the vaporized nitrogen gas (hereinafter referred to as "N ₂ gas") existing above the LN ₂ gas liquid surface that is stagnated is connected to the injection nozzle 7 in the upper part of the retention chamber 4. A pressure detector 11 and a pressure regulator 12, such as a relief valve, which can freely exhaust N ₂ gas are interposed in the conduit 9. 13 is a LN ₂ gas liquid level position detector in the retention chamber 4 using a capacitance sensor, etc.;
It is connected to a liquid level control device 14 using an indicating controller or a computer as shown in the figure. In addition, inside the retention chamber 4, there is a floating rocking suppression plate 15 for preventing the staying LN ₂ gas from rocking, and
Through hole 1 facing the outlet of LN ₂ gas supply pipe 6
6 and a flow relaxation device 17 were provided. The injection nozzle 7 is bent along the moving direction of the can body 18 to be injected to prevent the LN ₂ gas from scattering by colliding with the contents of the can, and is bent relative to the vertical direction according to the injection speed.
It has a bending angle of 45° to 80° and is attached by a nozzle clamp 19 to be replaceable. Further, the on-off valve device 8 moves a valve rod 20 penetrating through the retention chamber 4 to the can body 1 shown in the first figure using a drive device 21 using a solenoid.
The controller 23 is driven by a detection signal from a can body detector 22 that detects 8. The LN ₂ gas supply control device 3 detects the height position of the LN ₂ gas liquid level using the detector 13 provided in the retention chamber 4 shown in the second diagram, and sends a detection signal to the liquid level control device 1.
4 for pressurization to connect the vaporized gas region of the LN ₂ gas reservoir 2 from the N ₂ gas reservoir 24 for pressurization.
_N2 gas is supplied through the pipe line 25, which is the _N2 gas supply line, and the _LN2 gas in the _LN2 gas storage device 2 is pressurized.
The pressurized gas supply pipe 25 is provided in a pressurized gas supply pipe 25 that operates to supply LN ₂ gas to the retention chamber 4 through the pipe 6 and maintain the liquid level of the LN ₂ gas in the retention chamber 4 at a predetermined position. For example, it has a pressure regulating valve 26 using an electro-pneumatic conversion regulator or the like. With the above structure, first, the pressure inside the retention chamber 4 is maintained at a predetermined value by the pressure regulator 12 interposed in the vaporized gas discharge pipe 9. Then, the can body 18 is detected under the injection nozzle 7 by the can body detector 22.
When the liquid is transferred, the on-off valve device 8 is activated and the liquid is transferred from the retention chamber 4 of the injector 1 through the injection nozzle 7.
A small amount of LN ₂ gas is dripped into the can body 18 . When the LN ₂ gas liquid level in the retention chamber 4 falls during this continuous injection of LN ₂ gas, the liquid level control device 14 is activated by the detection signal from the LN ₂ gas liquid level position detector 13. The pressure regulating valve 26 of the pressurized gas supply pipe 25 connecting the N ₂ gas storage 24 and the LN ₂ gas storage 2 is operated, and the LN ₂ gas storage 2 is
Increase the pressurization pressure to the LN ₂ gas in the reservoir 2.
LN ₂ gas is supplied to the retention chamber 4 to maintain the LN ₂ gas liquid level at a predetermined position. On the other hand, in the retention chamber 4
When the LN ₂ gas liquid level rises above a predetermined position, the liquid level control device 14 operates the pressure regulating valve 26 based on the detection signal from the liquid level position detector 13, and the LN _{2 gas in the LN 2} gas storage 2 is _increased . The pressurization pressure is lowered to reduce the flow rate to the retention chamber 4 to maintain the LN ₂ gas liquid level at a predetermined position. When LN ₂ gas is supplied to the retention chamber 4, the flow relaxation device 17
The flow of the LN ₂ gas inside is relaxed, and furthermore, the swinging of the LN ₂ gas due to the outflow of the LN ₂ gas and the operation of the on-off valve device 8 is suppressed by the swing suppressing plate 15.
Stabilize the outflow of LN ₂ gas from the injection nozzle 7. Furthermore, when the pressure of _N2 gas above the _LN2 gas liquid level in the retention chamber 4 fluctuates due to the flow of _LN2 gas in the retention chamber 4, changes in insulation conditions, etc., and the pressure increases, vaporization occurs. Pressure regulator 12 via gas release line 9
The N ₂ gas is discharged and the pressure in the retention chamber 4 is maintained at a predetermined value, thereby stabilizing the outflow of the LN ₂ gas from the injection nozzle 7. In the case of the above implementation equipment, when injecting _LN2 gas
In order to prevent the flow and vibration of LN ₂ gas _, the flow relaxation device 17 and the vibration suppression plate 15 are used in combination. The object of the present invention can also be achieved simply by providing the retaining chamber 4 over the entire circumference in correspondence with the position of the inlet. More preferably, in addition to the mechanical control, 0.32
The nozzle diameter is usually suitable for quantitatively injecting a small amount of _LN2 gas on the order of ml.
In the case of an injection nozzle 7 of 1.0 to 4.0 mm, it is further important to maintain the N ₂ gas pressure in the retention chamber 4 in the range of 0.1 to 0.5 Kg/cm ² . That is, if the N ₂ gas pressure in the retention chamber 4 is less than 0.1 kg/cm ² , the dripping from the injection nozzle 7 becomes unstable due to the pressure regulation accuracy of the pressure regulator 12, making it difficult to inject a constant amount. Conversely, increase the _N2 gas pressure to 0.5Kg/ ^cm2
Given the above, there is no problem in terms of quantitative injection.
Canister 1 to be injected because the injection force of _LN2 gas is large
LN ₂ gas tends to scatter in fine particles when it collides with the contents of can ₁₈ .
Since it cannot be stopped inside the can, the pressure inside the can will vary widely. Furthermore, even when the N ₂ gas pressure in the retention chamber 4 is maintained at 0.1 to 0.5 Kg/cm ² by the pressure regulator 12, when continuously injecting a fixed amount, the N ₂ gas pressure in the retention chamber 4 is _N2 by designing the gas retention volume to be 1 to 5 times the volume of _LN2 gas.
It is preferable to reduce fluctuations in gas pressure. In other words, when the retention volume of N ₂ gas is less than 1 times the volume of LN ₂ gas, the pressure fluctuates greatly even when controlled by the pressure regulator 12, which often impedes the quantitative injection of LN ₂ gas. , if it is 5 times or more, N ₂
Although fluctuations in gas pressure can be reduced, the volume of the retention chamber 4 becomes large, which increases heat intrusion from the outside and increases the amount of vaporized gas generated. This makes it difficult to attach the lid to the lid tightening device. Next, an example of an experiment conducted using the quantitative injection device will be described. First, the can body thickness is 0.11mm filled with water at 95℃.
Results of filling 202D tin DI cans with LN ₂ gas at a rate of 350 cans per minute, tightening the aluminum lid after 2 seconds, lowering the can body temperature to 20°C, and measuring the internal pressure of the test cans (20 cans). If shown, it is as shown in the attached table.

[Table] In Examples 1 and 2 above, water is usually filled with water at 95℃.
The can internal pressure was 0.50 Kg/cm ² or higher, which is necessary for the can body to not deform when the can body temperature is lowered to 20°C, and the can body also showed good results with little variation in can internal pressure. (Effects of the Invention) As is clear from the above description, according to the present invention, the liquid level position of the liquefied gas in the liquefied gas retention chamber is controlled constant, the internal pressure in the retention chamber is maintained at a predetermined pressure, and the liquefied gas is When injecting gas continuously,
Since the liquefied gas is supplied to a position below the liquid level of the liquefied gas in the liquefied gas storage device and a position below the liquid level of the liquefied gas in the retention chamber, the supplied liquefied gas is not mixed with vaporized gas. By supplying liquefied gas, the liquefied gas in the retention chamber can be prevented from flowing due to mixing with vaporized gas, and furthermore, a liquefied gas flow mitigation device is installed at the liquefied gas injection port in the retention chamber, so that the inflow of liquefied gas can be prevented. The accompanying flow of liquefied gas in the retention chamber is relaxed, and a trace amount of liquefied gas can be quantitatively and reliably injected.

[Brief explanation of drawings]

The drawings show an example of the implementation of the present invention, and FIG. 1 is a general schematic diagram, and FIG. 2 is a cutaway sectional view of the syringe shown in FIG. 1. 2... Liquefied gas storage device, 3... Liquefied gas supply control device, 4... Liquefied gas retention chamber, 6... Liquefied gas supply path, 7... Injection nozzle, 8... Opening/closing valve device,
12...Pressure regulator, 13...Position detector, 17
... Flow relaxation device, 24 ... Pressurized vaporized gas storage device, 25 ... Pressurized gas supply pipe, 26 ... Pressure adjustment valve.

Claims (1)

[Claims] 1. An insulated liquefied gas retention chamber, an injection nozzle equipped with an on-off valve device connected to the liquefied gas in the chamber and opened and closed by a can body position detector, and a liquefied gas liquid in the chamber. a surface position detector, a pressure regulator in the chamber, a liquefied gas supply path connecting a position below the surface of the liquefied gas in the chamber and a position below the surface of the liquefied gas in the liquefied gas storage device; A liquefied gas flow relaxation device provided at the inlet to the retention chamber and a detection signal from the position detector supply the liquefied gas in the liquefied gas storage device into the retention chamber and measure the height of the liquid level of the liquefied gas in the chamber. A liquefied gas metering injection device comprising a liquefied gas supply control device for holding the liquefied gas in a predetermined position. 2. The liquefied gas supply control device includes a pressurized vaporized gas storage device connected to a vaporized gas region in the liquefied gas storage device through a pressurized vaporized gas supply path, and a pressure regulating valve interposed in the pressurized vaporized gas supply path. A liquefied gas metering injection device according to claim 1, characterized in that the device comprises: 3. Claim 1, characterized in that the injection nozzle has a nozzle diameter of 1.0 to 4.0 mm, and the pressure inside the liquefied gas retention chamber is controlled to 0.5 Kg/cm ² or less.
The liquefied gas metering injection device described in Section 1. 4. The liquefied gas metering injection device according to claim 1, wherein the volume of the vaporized gas in the liquefied gas retention chamber is controlled to be 1 to 5 times the volume of the liquefied gas in the chamber.