JP3701484B2 - Decompression mechanism of foam molding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure reducing mechanism for discharging steam supplied to a steam chamber of a mold of a foam molding machine.
[0002]
[Prior art]
Molding with a foam molding machine generally consists of the following steps.
(a) Clamping (move the movable mold to the fixed mold).
(b) Fill the pre-foamed resin beads into the cavity in the mold.
(c) Inject high temperature steam into the mold to foam the beads.
(d) Cooling the mold by injecting a small amount of cooling water into the mold and sucking it with a vacuum pump or the like to vaporize water adhering to the mold surface.
(e) Open the mold and take out the molded product.
[0003]
In the above process, in order to prevent water from being mixed into the foam-molded molded product, it is necessary to quickly discharge the steam supplied to the steam chamber. For this reason, the process (d) is provided.
[0004]
In this case, it is required that the steam in the steam chamber is effectively sucked by the vacuum pump. This is because if the vacuum suction by the vacuum pump is performed slowly, moisture is contained in the molded product, and a step of drying the molded product taken out to remove it is necessary.
[0005]
However, even if the vacuum pump is operated at the start of pressure reduction, it takes time to start the pressure reduction within a certain time after the pressure reduction starts, and the suction is slow and the suction efficiency is lowered. Therefore, a foam molding machine (capacitor (vapor condenser)) is disposed between the vapor chamber of the mold and the suction side of the vacuum pump as means for preventing the initial suction efficiency from being lowered and enhancing the steam suction action ( JP-B-62-28739, JP-A-62-132634, etc.).
[0006]
When sucking the vapor in the vapor chamber of the mold, the vacuum pump is operated, the cooling water is injected from the cooling water injection device, and the vacuum valve is opened. Then, the steam in the steam chamber is sucked into the condenser and condensed by the cooling water. Since the amount of steam sucked is reduced, the suction action of the vacuum pump is increased, and the remaining steam remaining in the steam chamber at the start of the cooling process is rapidly exhausted.
[0007]
In the steam chamber, the pressure is rapidly reduced as compared with the case without a condenser, and the remaining steam present in the molded body and the mold cavity is efficiently exhausted, and the molded body can be taken out from the mold in a dry state. Therefore, the drying process after shaping | molding can be made unnecessary. The cooling water and the condensed water droplets accumulate as stored water in the condenser, but can be discharged by opening the drain valve.
[0008]
However, even if a capacitor is provided, air remains in the capacitor and piping, so that the pressure is not sufficiently reduced immediately after the operation of the vacuum pump is started. In view of this, as a means for solving such a problem and obtaining a strong suction force immediately after the start of the suction of the steam in the steam chamber, a means provided with a vacuum tank has been proposed (Japanese Patent Laid-Open No. 1-148533).
[0009]
FIG. 3 is a diagram showing an outline of the configuration of a foam molding machine provided with such a vacuum tank and a capacitor. (31) is a mold. A vacuum tank (34) is provided in parallel with the vacuum pump (32) for the capacitor (35). (11) is a valve between the vacuum pump (32) and the vacuum tank (34), and (10) is a valve between the vacuum pump (32) and the condenser (35). (36) is a discharge line leading to the condenser (35), (37) is a steam line for supplying steam to the steam chamber of the mold (31), and (38) is a cooling water line for supplying cooling water to the steam chamber. .
[0010]
Prior to the suction of steam in the steam chamber, the valve (11) is first opened and the valve (10) is closed. Then, the vacuum pump (32) is operated. After the pressure in the vacuum tank (34) is sufficiently reduced, the valve (10) and the vacuum valve (9) are opened. Then, the vacuum tank (34) having a reduced pressure can be sucked with a large suction force from the beginning of the steam suction of the steam chamber.
[0011]
However, since the size of the vacuum tank (34) is actually limited, the initial suction capability is not always sufficient. In addition, when not sucking from the vapor chamber of the mold (31), the vacuum pump is used exclusively for decompression of the vacuum tank (34), but is not necessary after the vacuum tank (34) has been sufficiently decompressed. The vacuum pump (34) is temporarily unnecessary equipment.
[0012]
FIG. 4 is a diagram showing a system in which the vacuum lines (33) sharing the decompression of a plurality of foam molding machines are concentrated. (42a) and (42b) are common vacuum pumps connected to the common vacuum line (33). (45) is a common capacitor arranged in the common vacuum line (33).
[0013]
The discharge lines (36a), (36b), (36c),... Of each foam molding machine are connected to a common vacuum line (33). (46) is a control unit that controls the vacuum pumps (42a) and (42b) according to the pressure of the shared vacuum line (33), and (47) is a pressure switch for detecting the pressure of the shared vacuum line (33). It is.
[0014]
A common vacuum pump that performs centralized vacuum is connected to each foam molding machine via a common vacuum line (33), and all the molds are decompressed from the common vacuum line (33).
[0015]
However, since the vacuum pumps (42a) and (42b) need to handle the decompression of all the foam molding machines, it is necessary to have a large capacity with a margin.
[0016]
Furthermore, when a part of the plurality of foam molding machines constituting the system stops operating, it is difficult to balance the capacity of the vacuum pump and the number of foam molding machines. Conversely, when a foam molding machine is added, the capacity (capacity) of the vacuum pump becomes insufficient, making it difficult to support the expansion.
[0017]
[Problems to be solved by the invention]
Therefore, a vacuum mechanism that reduces the pressure of multiple foam molding machines can exert a strong suction force immediately after the start of suction, can efficiently use the vacuum pump as equipment, and the capacity of the vacuum pump and the number of foam molding machines Therefore, there is a demand for a pressure reducing mechanism for a foam molding machine that is easy to balance.
[0018]
[Means for Solving the Problems]
The decompression mechanism of the foam molding machine according to claim 1 is a decompression mechanism connected to a plurality of foam molding machines, each foam molding machine having an independent vacuum pump (2), and each vacuum pump ( 2) is characterized in that it is connected to the mold (1) of each foam molding machine and is also branched and connected to the common vacuum line (3).
[0019]
According to this, even if the vacuum pump provided in each foam molding machine does not suck from the mold of the foam molding machine in charge, it can assist the suction of the molds of other foam molding machines through the common vacuum line. Therefore, it will always work effectively and will not be wasted as equipment.
[0020]
In addition, when sucking from the mold of the foam molding machine in charge, each vacuum pump is more than necessary because it can be supported by the suction of a vacuum pump installed in another foam molding machine through the shared vacuum line. There is no need to be powerful.
[0021]
In addition, since each vacuum pump can be operated independently, not only when all of the plurality of foam molding machines constituting the system are operating, but also one or a plurality of them are at rest. Even in this case, it is possible to perform a balanced operation by appropriately operating according to the operation status of the foam molding machine. Moreover, when adding a foam molding machine, a vacuum pump can also be added as a set, making it easy to balance.
[0022]
A decompression mechanism for a foam molding machine according to a second aspect is the decompression mechanism according to the first aspect, wherein each foam molding machine is provided with at least one of an independent capacitor and an independent vacuum tank.
[0023]
According to this, it is possible to achieve further rapid pressure reduction in the initial stage of pressure reduction by using an independent capacitor or an independent vacuum tank.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to preferred embodiments.
[0025]
[Example 1]
FIG. 1 is a view showing a system including four foam molding machines and a decompression mechanism of the present embodiment. In the figure, (1) is a mold, (2) is a vacuum pump, (3) is a shared vacuum line, (6) is a discharge line, and (7) is a steam line that supplies steam to the steam chamber of the mold (1). (8) is a cooling water line for supplying cooling water to the steam chamber. (9) is a vacuum valve, (10) is a valve between the vacuum pump (2) and the discharge line (6), and (11) is a valve between the vacuum pump (2) and the common vacuum line (3). is there. (16) is the control unit that controls each vacuum pump (2a), (2b), (2c), (2d) according to the pressure of the shared vacuum line (3), and (7) is the shared vacuum line (3) It is a pressure switch for detecting the pressure.
[0026]
Turn on the vacuum pump (2) and depressurize the common vacuum line (3). When the pressure in the mold (1) is reduced, it is initially connected to both the common vacuum line (3) and the vacuum pump (2), and rapid pressure reduction can be performed by strong suction by both. Since the vacuum pump of other foam molding machines is connected to the common vacuum line (3), it is possible to use such a margin to exert a strong suction force that is connected to a large capacity vacuum pump. it can.
[0027]
In the second half of the suction, a strong suction force is no longer necessary, so the valve (11) is closed to disconnect the common vacuum line and connect only to the vacuum pump (2).
[0028]
If the mold (1) is not depressurized, the valve (10) is closed and the valve (11) is opened, contributing to the depressurization of the molds of other molding machines via the common vacuum line (3). To do.
[0029]
Each vacuum pump can be operated independently even if one or more of the foam molding machines that make up the system are at rest, so depending on the operating conditions of the foam molding machine. A well-balanced operation can be performed by operating the vacuum pump.
[0030]
On the other hand, when expanding the foam molding machine of the system, the capacity of the vacuum pump as a whole is not deficient by providing the expanded foam molding machine with a small vacuum pump.
[0031]
Therefore, as compared with the conventional centralized system shown in FIG. 4, it is easy to balance the capacity of the vacuum pump and the number of foam molding machines regardless of the operation status or expansion of the foam molding machines.
[0032]
[Example 2]
FIG. 2 is a view showing a system of a foam molding machine provided with this embodiment. The basic configuration is the same as in Example 1, except that each foam molding machine is equipped with a vacuum tank (4) and a capacitor (5). Thereby, it becomes easy to achieve a rapid pressure reduction in the initial stage of suction.
[0033]
(12) is a valve between the vacuum tank (4) and the common vacuum line (3), so that the vacuum state of the vacuum tank (4) can be easily maintained. This valve may be a normal on-off valve or a combination of a flow control valve and a check valve.
[0034]
In this embodiment, an example in which both the vacuum tank (4) and the capacitor (5) are provided is shown, but only one of them may be provided.
[0035]
【The invention's effect】
As described above, according to the present invention, in the decompression mechanism for decompressing a plurality of foam molding machines, a strong suction force can be exhibited immediately after the start of suction, the vacuum pump as equipment can be used efficiently, and the vacuum pump Provided is a pressure reducing mechanism for a foam molding machine that easily balances the capacity and the number of foam molding machines.
[Brief description of the drawings]
FIG. 1 is a diagram showing a system of a foam molding machine provided with a first embodiment.
FIG. 2 is a view showing a system of a foam molding machine provided with a second embodiment.
FIG. 3 is a diagram showing an outline of the configuration of a conventional foam molding machine (independent type).
FIG. 4 is a diagram showing an outline of the configuration of a conventional foam molding machine (centralized type).
[Explanation of symbols]
(1) Mold
(2) Vacuum pump
(3) Common vacuum line
(4) Vacuum tank
(5) Capacitor
(9) Vacuum valve

Claims (2)

A pressure reducing mechanism connected to a plurality of foam molding machines, each foam molding machine has an independent vacuum pump, and each vacuum pump is connected to a mold of each foam molding machine and branched. The pressure reducing mechanism of the foam molding machine is also connected to a common vacuum line. 2. The pressure reducing mechanism of a foam molding machine according to claim 1, wherein each foam molding machine includes at least one of an independent capacitor and an independent vacuum tank.

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