JP4580892B2 - Parison evacuation method and apparatus - Google Patents

Description

  The present invention relates to a evacuation method and apparatus for a parison, and in particular, an air tank is provided in a tube of a crosshead air pipe and a vacuum pump, and air in the parison is evacuated into a vacuum air tank to reduce noise during evacuation. The present invention relates to a novel improvement for reducing the amount of exhaust gas in a short time.

Conventionally, as this type of parison vacuum evacuation method and apparatus, a configuration shown in FIG. 6 has been adopted, although patent documents and the like are not particularly disclosed.
That is, what is indicated by reference numeral 1 in FIG. 6 is a cross head provided on the platform 2, and the parison 3 is pushed downward from the extrusion port 1 a of the cross head 1 and hangs down.

  Although the parison 3 is sandwiched between molds and is hollow-molded, the mold is not shown in FIG. 6, and the lower part 3 a of the parison 3 is configured to be pinched by a pinch device 4. .

  An air pipe 5 provided in a core (not shown) of the cross head 1 and for supplying pre-blow air for pre-blowing into the parison 3 is formed so as to protrude above the cross head 1. A pre-blow pipe 7 having a pre-blow electromagnetic valve 6 for supplying the pre-blow air 5 a is connected to 5.

  A vacuum ejector 9 is connected to the air pipe 5 via an electromagnetic valve 8 so that the air in the parison 3 can be forcibly exhausted by the vacuum ejector 9 and the parison 3 can be squeezed. It is configured.

  Next, in the configuration described above, the pre-blow solenoid valve 6 is opened while the lower part 3a of the parison 3 extruded from the crosshead 1 into the mold is pinched by the pinch device 4, and the solenoid valve 8 is When the valve is closed and the pre-blow air 5a is supplied to the air pipe 5, the parison 3 swells as indicated by the dotted line.

  Next, when the vacuum ejector 9 is operated with the pre-blow solenoid valve 6 closed and the solenoid valve 8 opened in the above-described state, the air in the parison 3 is exhausted to the outside by the vacuum ejector 9. The parison 3 is depressed as shown by the solid line.

The supply and exhaust of the pre-blow air 5a to the parison 3 shown in FIG. 6 are applied to the hollow molding method shown in FIG. 5, and are specifically shown in FIG.
That is, in the mold open state of FIG. 5A, the parison 3 from the cross head 11 hangs down in the mold 10 and reaches a predetermined length. 3 is pinched by the mold lower part 10a of the mold 10 or the pinch device 4 (in the case of B, the pinch device 4 is pinched), and in this pinch state, air from the crosshead 1 (other means is also possible) Pre-blow by supply.

  In the pre-blow described above, pre-blow is performed by an air amount based on software set in advance by the resin material of the parison 3, the cavity shape of the mold 10 and the like, and the outer surface 3c of the parison 3 expanded by this pre-blow is That is, the pre-blow operation is performed so as not to contact the mold inner surface 10b. The condition is set by software so that the thickness of Harrison 3 by pre-blow is equal to the thickness of the hollow molded product.

  Next, in the state of C, a part of the air in the parison 3 is exhausted by the cross head 1 (or other well-known exhaust means), and at this time, the inner surfaces 3b of the parison 3 are in contact with each other. Exhaust is performed in the absence.

  Next, in the state of D, the exhausted state is shown, and the parison 3 after pre-blow is held in a state where the inner surfaces 3b do not contact each other even in a deflated state.

  After the exhaust is completed, in the state E, when the mold 10 is closed, the air nozzle 11 is driven into the parison 3 and air is supplied into the parison 3, the parison 3 itself does not extend along the mold inner surface 10b. A hollow molded product having a uniform thickness can be obtained.

Therefore, in the above-mentioned process, the thickness of the parison 3 at the time of the pre-blow is controlled by software in which the air amount, air pressure, etc. are set in advance so as to be equal to the thickness of the molded hollow molded product. That is, the circumferential length of the parison 3 during pre-blow is controlled to be equal to the circumferential length of the mold inner surface 10b of the mold 10.
The hollow molding method shown in FIG. 5 was developed by the present applicant and was filed on December 8, 2005.

Since the conventional evacuation method and apparatus of the parison shown in FIG. 6 are configured as described above, the following problems exist.
In other words, since the air in the parison is exhausted by the vacuum ejector, a large amount of air is always required at high pressure, and it takes a long time to squeeze the parison during hollow molding. I had to wait until.
Further, the air exhausted from the parison by the vacuum ejector takes 4 seconds each time and is released into the atmosphere, so that the noise is intense and it is difficult to suppress the noise around the hollow molding machine.

The parison evacuation method according to the present invention is a parison evacuation method in which a parison extruded from a crosshead is once inflated by a preblow and then deflated by a vacuum pump, and the crosshead air tube and the crosshead Using an electromagnetic valve and an air tank provided between the vacuum pump and the vacuum inside the air tank in advance, the electromagnetic valve is opened and the air in the parison is instantaneously discharged into the air tank. A pre-blowing solenoid valve provided in the air pipe, and a pressure regulating valve and a flow regulating valve arranged in series between the air pipe and the solenoid valve upstream of the air tank; The exhaust time and the exhaust time of the air exhausted from the parison into the air tank by the pressure control valve and the flow control valve The Rukoto to control the a way it is possible to correspond to a plurality of parisons of different sizes, also, the vacuum exhaust system of the parison according to the present invention, after once inflated by pre-blow the parison extruded from the crosshead In the evacuation apparatus of Parison, which is evacuated by evacuation by a vacuum pump, an electromagnetic valve and an air tank provided between the air pipe of the cross head and the vacuum pump are used, and the inside of the air tank is previously evacuated. a configuration was air in the parison by opening the solenoid valve after the vacuum so as to instantaneously exhaust in the air tank by a pump, also the solenoid valve pre-blow provided in the air tube, Using a pressure regulating valve and a flow regulating valve arranged in series between the air pipe and the solenoid valve upstream of the air tank, The Rukoto to control the evacuation time and amount of exhaust air exhausted from the parison by serial pressure control valve and flow control valve into the air tank, a configuration is also available in different parison sizes.

Since the evacuation method and apparatus for a parison according to the present invention is configured as described above, the following effects can be obtained.
That is, the air in the parison, which is inflated by pre-blow using an air tank connected to the air pipe of the crosshead and the vacuum pump, is opened in the air tank by opening the electromagnetic stool of the air tank previously kept in a vacuum state. Since the air is exhausted instantaneously, the exhaust time is reduced to 1/3 of the conventional one, and since the air tank is not open to the atmosphere, the exhaust noise is low and the noise can be greatly reduced.
In addition, by providing a pressure adjustment valve, flow rate adjustment valve, and solenoid valve, it is possible to adjust the air pressure, flow rate, and air exhaust timing, and perform hollow molding by control according to the characteristics of the resin material. Can do.

The present invention relates to a vacuum exhaust method for a parison that exhausts air in a parison into an air pipe of a crosshead and a vacuum air tank, reduces noise during exhaust, and exhausts a large amount in a short time. And an apparatus.

Hereinafter, preferred embodiments of a method and an apparatus for evacuating a parison according to the present invention will be described with reference to the drawings.
In addition, the same code | symbol is attached | subjected and demonstrated about the same or equivalent part as a prior art example.
In Figure 1, those represented by the reference numeral 1 is a cross-head for extruding the parison 3 is provided Pratt home 2 from the extrusion port 1a, the parison 3, in a mold 10 as shown in FIG. 5 The lower part 3 a is positioned and pinched by the pinch device 4.

  A pre-blow pipe 7 having a pre-blow electromagnetic valve 6 is connected to an air pipe 5 provided in a core (not shown) of the crosshead 1, and the pre-blow air 5 a is passed through the air pipe 5 in the parison 3. So that pre-blow is performed.

On the platform 2, an air tank 20 and a vacuum pump 21 are installed in a state of being connected to each other by an air hose 22. A pressure adjusting valve 23 and a flow rate adjusting valve 24 are provided between the tank 20 and the air pipe 5. And the solenoid valve 8 is connected in a state where they are connected in series with each other.
Accordingly, electronic control by a control unit (not shown) using the electromagnetic valve 8 enables time control, pressure control by the pressure control valve 23, flow control by the flow control valve 24, and remote control of the exhaust timing. The operation can be easily performed.

  Next, the operation will be described. First, at the timing of hollow molding, while the parison 3 is being pushed out from the crosshead 1, the electromagnetic valve 8 is closed and the air tank 20 is evacuated by the vacuum pump 21 (shown in FIG. 2).

When the parison 3 reaches a predetermined length, the lower part 3a of the parison 3 is pinched by a pinch device 4 located below a mold (not shown).
Thereafter, the pre-blowing solenoid valve 6 is opened, and the pre-blowing air 5a is supplied into the parison 3 through the air pipe 5, and the parison 3 swells into a pre-blow state (shown in FIG. 3).

Thereafter, when the pre-blow solenoid valve 6 is closed and the solenoid valve 8 is opened, the air in the parison 3 is exhausted instantaneously (1.5 seconds) into the air tank 20 as shown in FIG. .
In this case, by using various vacuum pumps 21 having different sizes and displacements of the air tank 20, it is possible to cope with hollow molded products of various sizes.

In the air exhaust in the parison 3 by the air tank 20 described above, by providing the solenoid valves 6, 8, the pressure regulating valve 23 and the flow rate regulating valve 24, the state of the parison 3 and the hollow molding timing can be controlled by numerical control. Stability is very good.
In addition, when the parison 3 is sandwiched between molds and the molded product is cooled, air circulation may be performed as is well known, but it is effective to use the air tank 20 and the vacuum pump 21 of the present application.
In addition, by changing the size of the air tank 20 and the capacity of the vacuum pump 21, it is possible to deal with the parison 3 having different sizes.

It is a block diagram which shows the evacuation method and apparatus of a parison by this invention. It is an operation | movement figure which shows the evacuation state of the tank of FIG. It is an operation | movement figure which shows the state which expands a parison by the next operation | movement of FIG. It is an operation | movement figure which shows the evacuation state of the parison by a tank by the next operation | movement of FIG. It is process drawing which shows the state of the hollow shaping | molding by the swelling and exhaust_gas | exhaustion of this invention and the conventional parison. It is a block diagram which shows the conventional evacuation method and apparatus of a parison.

DESCRIPTION OF SYMBOLS 1 Crosshead 1a Extrusion port 2 Platform 3 Parison 3a Lower part 4 Pinch device 5 Air pipe 6 Solenoid valve for preblow 8 Solenoid valve 20 Air tank 21 Vacuum pump 22 Air hose

Claims (4)

In the evacuation method of a parison in which the parison (3) extruded from the crosshead (1) is inflated once by pre-blowing and then deflated by a vacuum pump (21).
Air tube of the crosshead (1) (5) and the vacuum pump solenoid valve which is provided between the (21) (8) and the air tank (20) using the previous non-air opening SL air tank (20) and opening the solenoid valve (8) after the vacuum by the vacuum pump the inside in advance (21), characterized in that the instantaneous exhaust to the air tank (20) in the air in said parison (3) How to evacuate Parison. A pre-blow solenoid valve (6) provided in the air pipe (5), and a pressure arranged in series between the air pipe (5) and the solenoid valve (8) upstream of the air tank (20). Exhaust of air exhausted from the parison (3) into the air tank (20) by the pressure regulating valve (23) and the flow regulating valve (24) using the regulating valve (23) and the flow regulating valve (24) time by the exhaust amount control child, parison method of evacuation of claim 1, wherein the in different parison (3) sizes are available. In the evacuation apparatus of the parison, the parison (3) extruded from the crosshead (1) is inflated once by pre-blowing and then deflated by a vacuum pump (21).
Air tube of the crosshead (1) (5) and the vacuum pump solenoid valve which is provided between the (21) (8) and the air tank (20) using the previous non-air opening SL air tank (20) the solenoid valve after the vacuum advance the vacuum pump the inside (21) (8) configured thing to instantaneous exhaust into the air in the opening to the parison (3) the air tank (20) The evacuation device of Parison characterized by. A pre-blow solenoid valve (6) provided in the air pipe (5), and a pressure arranged in series between the air pipe (5) and the solenoid valve (8) upstream of the air tank (20). Exhaust of air exhausted from the parison (3) into the air tank (20) by the pressure regulating valve (23) and the flow regulating valve (24) using the regulating valve (23) and the flow regulating valve (24) time by Rukoto to control the exhaust amount, the size of different parisons (3) to be vacuum exhaust device of the parison according to claim 3 Symbol mounting, characterized in that the by Uni configurations are available.

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