JPS6228600A - Fixed volume of liquefied gas supply device - Google Patents

Abstract

PURPOSE:To supply fixed volume of liquefied gas of constant temperature and pressure, by forming a closed loop by connecting a liquefied gas passage from the bottom of a liquefied gas storage tank to the upper portion thereof and providing a cooling device in a liquefied gas supply system. CONSTITUTION:A liquefied gas passage 3 makes a closed loop composed of a liquefied gas supply passage 4 from the bottom of a liquefied carbon dioxide gas storage tank 1 and a liquefied gas return passage 5 communicating with the upper portion of the liquefied carbon dioxide gas storage tank 1. On the other hand, the liquefied gas return passage 5 communicates with the liquefied carbon dioxide gas storage tank 1 through a heat exchanger 11 so that return liquid flowing in the return passage 5 is cooled by the heat exchanger 11 before it is discharged as a shower through a gaseous phase portion positioned at the upper portion of the liquefied carbon dioxide gas storage tank 1.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a device for supplying a fixed amount of liquefied gas to equipment that uses liquefied gas, such as a device for supplying liquefied gas for internal cooling to a synthetic resin blow molding equipment. It is used as a device to supply

(Prior Art) In devices that utilize the low-temperature thermal energy possessed by a liquefied bus, it is required to accurately control the temperature and supply amount of liquefied gas.

The conventional liquefied gas supply device (2) uses liquefied gas for internal cooling during resin blow molding.
A liquefied carbon dioxide gas supply path (L) is led out from the liquefied carbon dioxide gas supply path (L), and the tip of this liquefied carbon dioxide gas supply path (L) is communicated with the air blowing/zuru (N) of the blow molding machine via the blowing branch path (P). let me,
A flow meter (M) was installed in the branch path (P), and by detecting the supply amount with this flow meter (M), a constant flow rate of liquefied carbon dioxide gas was blown in for a certain period of time. .

(Problem to be solved) However, in this case, when the remaining amount of liquid in the liquefied gas storage tank (T) decreases due to the use of liquefied carbon dioxide gas, the storage tank (T)
The vapor pressure balance within the tank is disrupted, activating the vaporization of liquefied carbon dioxide and lowering the liquid temperature. For this reason, even if a fixed amount of liquefied carbon dioxide is injected into the molded product for a set amount of time, the temperature of the supplied liquid will fluctuate, causing the latent heat of vaporization and sensible heat of the liquefied carbon dioxide to fluctuate, making the cooling rate inconsistent. . Furthermore, since the vapor pressure in the storage tank decreases and the flow rate of the liquefied bus that is sent out decreases, there is also the problem that the amount of liquefied gas supplied fluctuates even if the liquefied gas is ejected for a certain period of time. For this reason, the liquefied gas supply amount must be set based on a high liquid temperature and a slow flow rate, which not only wastes the layer energy of the liquefied gas but also increases the mold occupation time. However, there is a problem in that the operating speed of the entire production line is slow, resulting in low production efficiency.

Furthermore, since the liquefied gas supply system is configured in an open loop, the liquefied gas is vaporized in the supply path due to heat entering from the outside acting on the liquefied gas supply system, and this vaporized gas is mixed into the liquefied gas. This causes an error in the amount of liquefied gas supplied. This results in a decrease in production efficiency.

(Means for Solving the Problems) The present invention provides a device that can efficiently supply a fixed amount of liquefied gas at constant temperature and pressure. By connecting the supply path and the liquefied gas return path, the liquefied gas flow path is constructed into a closed loop, and a liquid feeding pump is placed in the liquefied gas flow path to circulate the liquefied gas. A cooling device for maintaining the liquid temperature of the liquefied gas at a constant level is installed in the system, and the liquefied gas maintained at a constant temperature is supplied to the liquefied gas using equipment.

(Function) According to the present invention, a cooling device is provided in the liquefied gas supply system, and a liquid feeding pump is arranged in the liquefied gas supply path to supply the liquefied gas at a constant temperature (for example, -30°C) at a constant pressure. Since the liquefied gas is supplied to the device in use in this state, even if the liquefied gas is supplied to the device in use by time control, the amount of supply is stable and the amount of heat retained is also stable. Furthermore, since the liquefied gas flow path is formed in a closed loop to circulate the liquefied gas, even if it is gasified in the piping system due to the influence of heat intrusion from the outside, the gas components will be circulated. The liquefied gas will flow into the liquefied gas return path along with the liquid flow, and the gas will not enter the device in use, and a fixed amount of liquefied gas will be sent to the device in use.

(Example) FIG. 1 shows a flowchart in the case where liquefied gas is supplied to the inside of a blow-molded synthetic resin product and used as a cooling medium.

This liquefied gas quantitative supply device has a liquefied carbon dioxide gas storage tank (1
) was derived from the blow molding machine (2) with a specific carbon dioxide gas of 1.
The liquefied carbon dioxide gas flow path (3) is designed to supply a fixed amount of liquefied carbon dioxide gas in order to cool the resin molded product from the inside using the heat of vaporization of the liquefied carbon dioxide gas. The liquefied gas supply path (4) led out from the bottom of the storage tank (1) and the liquefied gas return path (5) that communicates with the top of the liquefied carbon dioxide storage tank (1) form a closed loop. Branch pipe (6) branched from the liquefied gas supply path (4)
) Blow molding! It is connected to the nozzle (8) of (2) and formed in the liquefied gas usage section. A liquid pump (9) is disposed in the middle of the liquefied gas supply path (4), and the flow rate of the liquefied gas flowing through the liquefied gas supply path (4) is controlled by the liquid pump (9).
The flow rate is set to be 5 to 15 times the amount of liquefied gas consumed by the blow molding machine (2) by a flow rate control valve (10) disposed downstream of the blow molding machine (2).

On the other hand, the liquefied gas return path (5) is communicated with the liquefied carbon dioxide storage tank (1) via the heat exchanger (11), and the return liquid flowing in the return path (5) is connected to the heat exchanger (11). After being cooled within the liquefied carbon dioxide storage tank (1), it is released in the form of a shower in the gas phase section of the upper part of the liquefied carbon dioxide gas storage tank (1). in this way,
When the heat exchanger (5) is installed in the liquefied carbon dioxide return path (11), the cooled return liquid flows into the large capacity liquefied carbon dioxide storage tank (1), so that the liquefied carbon dioxide gas can be stored. Tank (
In addition to making it easier to control the liquid temperature in step 1), since the returned liquid is released into the gas phase in a shower, a gas-liquid equilibrium state is maintained within the storage tank (1). Inside, liquefied carbon dioxide gas at a constant temperature and pressure is obtained.

As a result, most of the liquefied carbon dioxide ice drawn out from the liquefied carbon dioxide gas storage tank (1) is circulated through the gas flow path (3). In this case, the liquid temperature of the liquefied gas returned to the liquefied gas storage tank (1) is controlled by the heat exchanger (11).
The liquid temperature is controlled to be equal to the liquid temperature derived from 1).

The heat exchanger (11) uses Freon R22 as a refrigerant,
The returning liquid is cooled with this refrigerant, the gas components mixed in the returning liquid are condensed, and the returned liquid is returned to the liquefied carbon dioxide gas storage tank (1) in a gas-free state. Heat exchanger(
After the heat exchange in step 11), the refrigerant is frozen! It is condensed in (12) and fed into the heat exchanger (11) again.

Branch pipe (6) branched out from the liquefied gas supply path (4)
As shown in Figure 2, the stainless steel bellows tube (13)
The outer surface of the nozzle (8) is covered with a rubber heat insulating layer (I4), and the outer surface of the rubber heat insulating layer (14) is covered with a mesh body (15), so that the nozzle (8) can be moved up and down. Further, this branch pipe (6) is formed so that its cross-sectional area becomes smaller as it goes from the outlet base side to the outlet end side. By configuring each branch pipe (6) in this way, even if the liquefied carbon dioxide gas is vaporized in the branch pipe (6) and a gas component is generated, the vaporized gas component is transferred to the liquefied gas supply path ( 4)
It escapes to the side and does not flow into the molding machine.

3 and 4 show another embodiment of the present invention, and the one shown in FIG. 3 has a liquefied carbon dioxide gas storage tank (1) and a heat exchanger ( 11) are connected by a cooling pipe (16) to form a liquefied gas cooling system, and the liquefied carbon dioxide in the liquefied carbon dioxide storage tank (1) is transferred to the heat exchanger (1).
1) The temperature of the liquefied gas in the storage tank (1) is maintained at a constant temperature by passing the gas through the storage tank (1). As a variant of this embodiment, it is conceivable to arrange the heat exchanger (11) in the liquefied gas storage tank (1) for direct heat exchange.

In the system shown in Fig. 4, a heat exchanger (11) is arranged in the liquefied gas supply path (4) downstream of the liquid pump (9), and the liquefied gas sent from the liquid pump (9) is The material is kept at a constant temperature and supplied to the blow molding machine (2).

In each of the above embodiments, a case has been described in which liquefied carbon dioxide gas is supplied as a cooling medium to a resin blow molding machine, but the present invention can be used, for example, to supply a fixed amount of liquefied gas in various types of refrigeration equipment.

In the liquefied gas quantitative supply device having the above configuration, a liquid sending pump (9) is arranged in the liquefied gas supply path (4), and a cooling device (heat exchanger) is arranged in the liquefied gas supply system. Therefore, it is possible to supply a fixed amount of liquefied gas at constant temperature and pressure to the liquefied gas using device, and the amount of heat retained therein can be maintained constant.

(Effects) In the present invention, the liquefied gas flow path led out from the bottom of the liquefied gas storage tank is connected to the top of the liquefied gas storage tank to form a closed loop, and a cooling device is disposed in the liquefied gas supply system. Since the liquid pump is disposed in the liquefied gas supply path that is open between the liquefied gas storage tank and the liquefied gas usage device, it is possible to supply a fixed amount of liquefied gas at a constant temperature and pressure to the device that uses liquefied gas. As a result, it is possible to obtain stable low-temperature thermal energy at all times, making it possible to set machining times without energy loss, increasing the work speed before and after equipment using liquefied gas, and It is possible to increase production efficiency by increasing operating efficiency.

Moreover, the structure is such that the liquefied gas flow path is piped in a closed loop, a pump is interposed in the liquefied gas supply path, and a cooling device is installed in the liquefied gas supply system, so it can be used with existing equipment. It can be easily implemented.

[Brief explanation of the drawing]

Fig. 1 is a flowchart when supplying liquefied gas to a blow molding machine, Fig. 2 is a vertical cross-sectional view of a branch pipe, Figs. This is a flowchart. 1.!・Liquefied gas storage tank, 2...Liquefied gas usage equipment (
Blow molding P/! i), 3... liquefied gas flow path, 4
... Liquefied gas supply path, 5... Liquefied gas return path, 9.
...Liquid pump, 11...Cooling device (heat exchanger), 1
6... Cooling piping. Patent applicant: Iwatani Sangyo Co., Ltd. Figure 3, No. 40, 2nd hearing

Claims (1)

[Claims] 1. The liquefied gas supply path (4) led out from the bottom of the liquefied gas storage tank (1) is connected to the liquefied gas usage device (2), and the liquefied gas usage device (2) and the liquefied gas The liquefied gas flow path (3) is configured as a closed loop by communicating with the upper part of the gas storage tank (1) through a liquefied gas return path (5), and a liquid feeding pump (9) is installed in the liquefied gas supply path (3). A quantitative supply device 2 for liquefied gas, characterized in that a cooling device (11) for maintaining a constant temperature of the liquefied gas is attached to a liquefied gas supply system including a liquefied gas storage tank (1). The device (11) is arranged in the liquefied gas flow path (3) on the downstream side of the liquid feeding pump (9), and the liquefied gas quantitative supply device 3 and the cooling device (11) are The liquefied gas quantitative supply device 4 described in claim 2 is arranged in the gas return path (5), and the cooling device (11) is arranged in the liquefied gas supply path (4) in claim 2. The liquefied gas quantitative supply device 5 described in
Claim 1) A quantitative supply device 6 for liquefied gas according to claim 1, configured to perform cooling in accordance with claim 1; The range of liquefied gas quantitative supply device 7 and the heat exchange part of the cooling device (11) described in item 5 are connected to the liquefied gas storage tank (1
) The liquefied gas quantitative supply device 8 and the liquefied gas storage tank according to claim 5, which are arranged outside the storage tank (1) and the heat exchange section through a cooling pipe (16). Claims 1 to 7 are constructed so that the return liquid is spouted in a shower form from the terminal end of the liquefied gas return path (5) communicating with the upper part of the liquefied gas return path (5).
Liquefied gas quantitative supply device described in any one of paragraphs