JP2840892B2 - Liquefied gas supply device for foaming - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection liquefied gas supply device for foaming.

[0002]

2. Description of the Related Art When a foamed coaxial cable or the like is manufactured, a long conductor is passed through an extruder, the conductor is coated with a foamed resin in the extruder, and a liquefied gas for foaming is injected into the foamed resin. Liquefied gas was injected by the supply device.

[0003] However, a conventional gas supply apparatus for injecting and liquefied gas for foaming uses a single gas cylinder filled with an infused and liquefied gas for foaming. If the gas tank runs out of liquefied gas, one gas cylinder is added to a new gas cylinder. It was switching sequentially one by one.

[0004]

Therefore, when the liquefied gas in the gas cylinder runs out, the liquefied gas is not injected into the foamed resin until the gas cylinder is switched to a new gas cylinder, and a defective portion where the foamed resin does not foam is formed. Will be done.

In view of the above, the present invention provides a liquefied gas supply apparatus which can always inject a liquefied gas for foaming into a foamed resin and does not form a defective portion in a manufactured coaxial cable or the like. The purpose is to:

[0006]

In order to achieve the above-mentioned object, a foaming injection gas supply device according to the present invention comprises: a plurality of gas cylinders filled with a foaming injection liquefied gas; An intermediate tank to be stored, a gas supply path for supplying the liquefied gas in the gas cylinder into the intermediate tank, the gas cylinder being exchangeably connected, and a gas supply path interposed in a part of the gas supply path, Switching means for selectively sending liquefied gas from the plurality of gas cylinders to the intermediate tank, a gas injection path for injecting the liquefied gas in the intermediate tank into the foamed resin, and storage in the intermediate tank Detecting means for detecting the amount.

[0007]

Since the liquefied gas in the intermediate tank is injected into the foamed resin through the gas injection path, first, the liquefied gas of one gas cylinder is supplied into the intermediate tank through the gas supply path. When the cable production line is driven in this state, the liquefied gas in one gas cylinder is supplied into the intermediate tank, and the liquefied gas in the intermediate tank is injected into the foamed resin, whereby the cable is manufactured.

When the liquefied gas in the above-mentioned one gas cylinder is exhausted, it can be known by the detecting means.
The switching means can supply the liquefied gas to the intermediate tank by using another new gas cylinder filled with the liquefied gas, and the liquefied gas can be injected into the foamed resin from the intermediate tank.

That is, even when the liquefied gas in one gas cylinder is exhausted, the liquefied gas is sufficiently stored in the intermediate tank, and the foamed resin can be foamed by the liquefied gas.

Further, since each gas cylinder can be exchanged with respect to the gas supply path, a new gas cylinder can be used while the liquefied gas-free gas cylinder is being injected into the foamed resin by another gas cylinder. Can be replaced.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing embodiments.

FIG. 1 and FIG. 2 show an injection liquefied gas supply apparatus for foaming according to the present invention. This apparatus is, for example, provided in an extruder for coating a linear conductor with a foamed resin. (For example, Freon 22) is injected under high pressure to foam the foamed resin.

The apparatus comprises a plurality (two in this embodiment) of gas cylinders 1 and 1 filled with the injection liquefied gas G for foaming, and an intermediate tank 2 for temporarily storing the liquefied gas.
A gas supply path 3 for supplying the liquefied gas G in the gas cylinder 1 to the intermediate tank 2; and a switching means 4 for sending the liquefied gas G from the plurality of gas cylinders 1 to the intermediate tank 2. A gas injection path 5 for injecting the liquefied gas G in the intermediate tank 2 into the foamed resin; and a detecting means 6 for detecting the storage amount of the liquefied gas G in the intermediate tank 2.

The gas cylinder 1 has an upper opening covered with a lid member 7. The lid member 7 has a first small-diameter tube 9 reaching almost to a bottom wall 8, and a short second small tube 9. A diameter pipe 10 is provided. Hereinafter, the gas cylinder 1 on the left side in the drawing will be referred to as the gas cylinder (a), and the gas cylinder 1 on the right side.
Is called a gas cylinder in Russia.

The gas supply path 3 is provided with a gas cylinder 11 filled with a pressurizing gas such as nitrogen gas and the above-mentioned switching means 4. Here, the switching means 4 includes four first, second, third, and fourth switching valves 12, 13, 14, and 15.

The gas supply path 3 is provided with a pipe 16 for communicating and connecting the gas cylinder 11 and the first switching valve 12, and a first switching valve 12.
A pipe 17 for communicating and connecting the second small diameter pipe 10 of the gas cylinder 1 with the first small diameter pipe 9 and the third switching valve of the gas cylinder 1
14, a pipe 19 for communicating and connecting the pipe 16 to the second switching valve 13, and a pipe 20 for communicating and connecting the second switching valve to the second small-diameter pipe 10 of the gas cylinder 1. A pipe 21 for communicating and connecting the first small-diameter pipe 9 of the gas cylinder 1 and the fourth switching valve 15, and a pipe 22 for communicating and connecting the third and fourth switching valves 14 and 15 and the intermediate tank 2. , And piping 16
Is provided with a pressure gauge 23 and a safety valve 24 for gas purge.

The gas cylinder 1 for the pipes 17, 18, 20, 21
At the end on the side, a valve 25 of the lid member 7 of the cylinder 1 is detachably attached. That is, each cylinder 1 is detachable from the gas supply path 3 and can be replaced.

Thus, the intermediate tank 2 has the upper opening 26.
As shown in FIG. 3, a gas supply pipe 28 is communicatively connected to the upper opening 26, and a joint member 29 is connected to the gas supply pipe 28.

That is, the gas supply pipe 28 includes an outer pipe 32 in which a lower end screw portion 30 is screwed into a screw hole 31 of the upper opening 26, and an outer pipe 32.
The joint member 29 is connected to a supply pipe 34 connected to the inner pipe 33 and a safety valve 35 for gas purge (see FIG. 1 or 2). Pipe
The pipe 36 is connected to a pipe 37 which is connected to the detecting means 6.

Therefore, the liquefied gas G from the gas supply path 3 is supplied to the intermediate tank 2 through the supply pipe 34, the joint member 29, and the inner pipe 33 of the gas supply pipe 28, and the nitrogen gas and the like in the intermediate tank 2 The pressing gas of the gap 38 between the inner tube 33 and the outer tube 32,
It is discharged to the outside via the joint member 29, the pipe 36 and the safety valve 35.

Thus, the detecting means 6 comprises a liquid level gauge 40, a sensor 41 for detecting the position of the liquid level of the liquid level gauge 40, and a sensor 41 for detecting that the liquid level of the liquid level gauge is lower than a predetermined level. The level indicator 40 is provided with a warning lamp 42 that is turned on, and the like. The level gauge 40 is a pipe that communicates and connects the above-described pipe 37 with the lower opening of the level gauge 40 and the lower opening 27 of the intermediate tank 2. 43, it is communicatively connected to the intermediate tank 2.

That is, the inside of the liquid level gauge 40 and the inside of the intermediate tank 2 are maintained at the same pressure, and the liquid level (liquefied gas G) of the liquid level gauge 40 and the liquid (liquefied gas G) in the intermediate tank 2 are maintained. And the same height as the liquid level. Therefore, detecting the position of the liquid surface of the liquid level gauge 40 means detecting the position of the liquid surface in the intermediate tank 2.

Thus, the gas injection path 5 is provided with a flow meter 44,
Switching valves 45 and 46, a fluid pressure gauge 47 and the like are interposed, and a pipe 48 that connects and connects the flow meter 44 and the pipe 43, a pipe 49 that connects and connects the switching valve 45 and the flow meter 44, and a pipe 49. A pipe 50 for communicating and connecting the liquefied gas G to the extruder (not shown) from the switch valve 45, and a liquefied gas G to the extruder (not shown) from the switch valve 46. Piping 52 for
It has. 53 is a joint member for communicating and connecting the pipe 43 and the pipe 48.

Next, a method of using the gas supply device configured as described above will be described.

First, all valves are closed and the gas cylinder is closed.
The gas pressure of the pressing gas such as nitrogen gas from 11 is set to a predetermined pressure (for example, 15 kg / cm ² ). The adjustment at the time of pressure over is performed by adjusting the purge safety valve 24.

Next, the first switching valve 12 is opened, the valve 25 on the pipe 17 of the gas cylinder 1 is opened, and the valve 25 on the pipe 18 of the gas cylinder 1 is opened. As a state, the second switching valve 14 is opened. Then, the purge safety valve 35 is opened, the liquefied gas G is supplied into the intermediate tank 2, and the safety valve 35 is closed when the liquid level of the liquefied gas G in the intermediate tank 2 reaches the upper opening 26. And

Accordingly, as shown in FIG. 1, the liquid level of the liquid level gauge 40 is at an intermediate position of the liquid level gauge 40 (that is, when the liquid level is lower than the intermediate position, the alarm lamp 42 is turned on. Position).

Then, in this state, the switching valves 45 and 46 are opened, and the liquefied gas G in the intermediate tank 2 is injected into each extruder. In this case, the amount of liquefied gas G supplied to each extruder from the intermediate tank 2 and the
Is almost the same as the amount of liquefied gas G supplied to the
The liquid level 40 (and thus the liquid level in the intermediate tank 2) is kept substantially constant. In addition, the liquefied gas G pressurized at a predetermined pressure by a pressurizer (not shown) is injected into the extruder.

When the liquefied gas G in the gas cylinder 1 is exhausted, the pressing gas such as nitrogen gas which has entered the gas cylinder 1 enters the intermediate tank 2 via the gas supply path 3 directly. The liquid level in the intermediate tank 2 starts to drop as shown in FIG. That is, if the liquid level of the liquid level gauge 40 also starts to drop and the liquid level drops below a predetermined level (that is, the middle position in the vertical direction of the liquid level gauge), the sensor 41 detects that,
By turning on the alarm lamp 42, the worker can grasp the fact (the liquefied gas in the gas cylinder 1 has run out). Of course, it can be seen from the liquid level meter 40 that the liquid level is lower than the predetermined level.

In this case, the second switching valve 13 is opened, the valve 25 on the pipe 20 of the gas cylinder 1 is opened, and the valve 25 on the pipe 21 of the gas cylinder 1 is further opened.
Is opened, and the fourth switching valve 15 is opened.

Next, the first switching valve 12, the third switching valve 14, and both valves 25, 25 of the gas cylinder 1 are closed.

Therefore, the liquefied gas G of the gas cylinder 1 enters the intermediate tank 2. At this time, the purge safety valve 35 is opened, and the pressing gas such as nitrogen gas in the intermediate tank 2 is opened. Liquefied gas G as shown in FIG.
The safety valve 35 is closed by setting the liquid level of the liquid to reach the upper opening 26. In this case, the alarm lamp 42 and the like are reset. That is, when the liquid level of the liquid level gauge 40 falls below a predetermined level, the alarm lamp 42 is set to be turned on.

That is, the liquefied gas G is supplied from the gas cylinder 1 to the intermediate tank 2 and supplied from the intermediate tank 2 to each extruder.

At this time, the gas cylinder 1 having lost the liquefied gas G can be removed from the gas supply path 3 and replaced with a new gas cylinder 1 filled with the liquefied gas G. If gas G runs out,
As in the case described above, it is possible to confirm that the liquefied gas G in the gas cylinder 1 in B is exhausted, and it is possible to switch to the new gas cylinder 1 in A. When replacing the gas cylinder 1 in which the liquefied gas G has disappeared, the gas cylinder 1 is removed from the gas supply path 3 and the gas cylinder 1 is removed.
Is again filled with the liquefied gas G, and the gas cylinder 1 is connected to the gas supply path 3 again.

Therefore, even when the liquefied gas G in the supplied gas cylinder 1 runs out, the injection of the liquefied gas G into the extruder does not stop, and there is no unfoamed portion in the foamed resin. The manufactured product will be stable.

The present invention is not limited to the above-described embodiment, and the design can be freely changed without departing from the gist of the present invention. For example, the number of gas cylinders 1 connected to the gas supply path 3 is three or more. And gas cylinder 1,
The permissible capacity of the liquefied gas G in the intermediate tank 2 can also be set freely, and the liquid level of the liquid level gauge 40 at which the alarm lamp 42 lights up can be freely changed. Further, when the liquid level falls below a predetermined level, an alarm sound may be generated.

[0037]

Since the present invention is configured as described above, the following effects can be obtained.

Even when the liquefied gas G in one gas cylinder 1 is exhausted, the liquefied gas G is introduced into the foamed resin without interruption.
Can be injected, a non-foamed portion does not occur in the product (no loss portion occurs), and a high-quality stable product can be provided at low cost. Further, even if the liquefied gas G of one gas cylinder 1 is exhausted, the liquefied gas G of the one gas cylinder 1 can be completely used because the liquefied gas G can be injected into the foamed resin. It is not necessary to check the remaining amount in the inside, and there is an advantage that the operation is simplified.

[Brief description of the drawings]

FIG. 1 is a simplified overall view showing one embodiment of the present invention.

FIG. 2 is a simplified overall view.

FIG. 3 is an enlarged sectional view of a main part of the intermediate tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas cylinder 2 Intermediate tank 3 Gas supply path 4 Switching means 5 Gas injection path 6 Detection means G Injected liquefied gas for foaming

Claims (1)

(57) [Claims] 1. A plurality of gas cylinders filled with an injection liquefied gas for foaming, an intermediate tank for temporarily storing the liquefied gas, and the gas cylinder being exchangeably connected to allow the liquefied gas in the gas cylinder to be stored in the intermediate tank. A gas supply path for supplying the gas into the tank, switching means interposed in a part of the gas supply path, for selectively sending the liquefied gas from the plurality of gas cylinders to the intermediate tank; An injection liquefied gas supply device for foaming, comprising: a gas injection path for injecting a liquefied gas in a tank into a foamed resin; and a detecting means for detecting a storage amount in the intermediate tank.