JPS6123099B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a foam molding device that can discharge heated steam, cooling water, etc. in a steam chamber from the same discharge pipe, and can always The aim is to provide a device that can exhibit optimal discharge capacity.

In the past, when steam and cooling water were discharged from the same discharge pipe during foam molding, the diameter of the drain pipe was increased to shorten the time required to discharge the cooling water to enable rapid drainage. When steam or condensed water is discharged in the heating process, the large-diameter drain pipe causes the heated steam supplied to the steam chamber to be discharged without sufficient heat transfer to the mold, resulting in poor thermal efficiency. Therefore, in order to perform sufficient heating,
An excessive amount of steam was required, resulting in a large amount of economic loss in thermal energy, etc. In order to solve the above-mentioned drawbacks, a method of separately providing a large-diameter drain pipe for cooling water and a small-diameter drain pipe for steam in each mold was also considered (Japanese Patent Application Laid-open No. 106176/1983). ), it is necessary to install two pipes and a valve to each pipe, and further improvements have been desired in terms of the effort and cost of operating the valves at two locations.

Therefore, the present invention provides a foam molding device in which a single discharge pipe is used to discharge cooling water and steam, and which also has an optimal discharge capacity in each molding process. In an apparatus for performing foam molding by filling the cavity of a mold with a raw material made of expandable thermoplastic resin particles and heating and expanding the raw material with steam, a discharge pipe is connected to the steam chamber of each mold, A drain valve equipped with an opening adjustment mechanism that can freely adjust the opening area is attached to the drain pipe, and the opening of the drain valve is adjusted by moving a valve body within the drain valve using a cylinder. It is characterized by being able to be adjusted by changing the air pressure.

Next, embodiments of the present invention will be illustrated below with reference to the drawings.

In the mold shown in Fig. 1, the cavity mold 1 is a fixed mold, and the core mold 2 is a movable mold, and foam is formed in the mold cavity 3 formed when the two molds 1 and 2 are brought together. The raw material is filled with thermoplastic resin particles. Each mold 1, 2 has a steam chamber 1
0, 20 are provided, and steam supply pipes 11, 21 and cooling water supply pipes 12, 22 are connected to the steam chambers 10, 20, and facing the mold cavities 3 of the molds 1, 2. A large number of steam holes 13, 23 are provided on the sides. Other components such as a mold moving cylinder 4 and a raw material filling device (not shown) are completely the same as those of the conventional device.

In this implementation device, each steam chamber 1
0 and 20 have exhaust pipes 5 for both steam and cooling water, etc.
are connected to each other, and a drain valve 50 is attached to each discharge pipe 5. The drain valve 50 is provided with an opening adjustment mechanism in which a valve body 52 is moved within the drain valve by a cylinder 52, and the opening area can be freely adjusted by changing air pressure, thereby adjusting the discharge capacity of the drain pipe 5. It has become possible to change freely.

Various types of structures can be considered for the drain valve 50, but it is necessary that the opening degree can be finely adjusted to any state from fully closed to fully open, and that it can also be remotely controlled and automated. is preferable, and an example of the drain valve 50 is illustrated below in FIG.

The drain valve 50 has a valve body 52 that matches the valve seat 51.
is connected to a piston 54 that slides inside a cylinder 52 behind it, and the piston 54 and valve body 52 are always pressed toward the valve seat 51 by a spring 55, and the valve body 52 The seat 51 is closed. The air pipe 6 is connected to the air intake port formed at the bottom of the cylinder 53.
Two electromagnetic valves 60 and 61 are attached in parallel to the air pipe 6, and a pressure regulating valve 62 is connected in series to one of the electromagnetic valves 61. This pressure regulating valve 62 adjusts the high pressure air from the air supply source to an appropriate pressure and controls the drain valve 5.
This is for feeding the gas into the cylinder 53 of 0, and is for reducing the original pressure of, for example, 6 kg/cm ² to 1.5 to 2 kg/cm ² . When both solenoid valves 60 and 61 are closed and air is not sent to the cylinder 53, the valve body 52
is pressed by the spring 55 to close the valve seat 51, and the drain valve 50 is fully closed (second
figure). Next, when the solenoid valve 61 on the side to which the pressure regulating valve 62 is attached is opened, reduced pressure air (for example, 1.5 kg/cm ² ) is sent into the cylinder 53, which pulls up the valve body 52 against the spring 55. The valve body 52 stops at a position where the air pressure and the force of the spring 55 are balanced, and the drain valve 50 is therefore partially opened (FIG. 3). Also, if the solenoid valve 60 on the opposite side is opened, high-pressure air (for example, 5 kg/
cm ² ) is fed directly into the cylinder 53, so the valve body 52 is pulled up to the top and the drain valve 50
is fully opened (Figure 4).

In any of the above cases, in order to close the valve 50 once opened again, it is necessary to release the supplied air pressure.
For this reason, one of the solenoid valves 60 and 61 has a four-way port, and the operation of this solenoid valve causes the drain valve 50 to open.
Exhaust the air pressure applied to the cylinder 53 of
The force of the spring 55 pushes the valve body 52 toward the valve seat 51 again, returning the drainer valve 50 to the fully closed state. As a method for exhausting air pressure, it is also possible to install a solenoid valve exclusively for exhaust in the air piping 6 in addition to the above-mentioned solenoid valves 60 and 61. In addition, the opening area when only a portion of the drain valve 50 is opened is determined by adjusting the adjustment pressure of the pressure regulating valve 62, so that the force of the air sent into the cylinder 53 of the drain valve 50 to pull up the valve body 52 can be adjusted. This allows the opening area of the drain valve 50 to be changed freely.

If the drain valve 50 as described above is used, the solenoid valve 6 can control the fully open, partially open, and fully closed states.
It can be automatically selected by operating the pressure control valve 62, and the opening area when partially opened can be freely adjusted by adjusting the pressure regulating valve 62, making it very suitable.

Next, in order to perform foam molding using the above-mentioned molding device, first, both molds 1 and 2 of the molding device are closed, and a filling step is performed in which the mold cavity 3 formed between both molds 1 and 2 is filled with raw material. After that, during the mold heating process, both the drain valves 50 of both molds 1 and 2 are partially opened (approximately 1/3
When heated steam is sent into the steam chambers 10 and 20 from the steam supply pipes 11 and 21, the steam that has finished heating the molds 1 and 2 and the condensed water are partially discharged through the discharge pipe 5. Drain valve 50 in open state
Since the steam is discharged little by little, the thermal energy of the steam can be used effectively and without waste.

Next, in the one-sided heating process, the drain valve 50 of one of the two molds 1 and 2 is fully closed, and the drain valve 50 of the other mold is left partially open. Furthermore, steam is fed only to the steam chamber of the mold on the side where the drain valve 50 is fully closed. Therefore, the steam enters the mold cavity 3 from one steam chamber and heats the raw material, and then enters the other steam chamber and is discharged through the drain valve 50, which is partially open, through the discharge pipe 5. In this case as well, heating efficiency is improved since excessive steam is not discharged. In the main heating process, the drain valves 50 of both molds 1 and 2 are fully closed, and steam is sent into both steam chambers 10 and 20 to fill them and heat and expand the expandable thermoplastic resin particles that serve as the raw material. fuse together. After the main heating process, in the cooling process, the steam supply pipes 11 and 21 are closed, and cooling water is supplied from the cooling water supply pipes 12 and 22 to the steam chamber 1.
Send it within 0.20. At this time, the drain valves 50 of the discharge pipes 5 are all fully opened so that a large amount of cooling water that has finished cooling the molds 1 and 2 can be quickly discharged.

After the molds 1 and 2 and the molded product have been sufficiently cooled,
Open the molds 1 and 2 and take out the molded product in the mold cavity 3.
By repeating the series of molding steps described above, foamed molded products can be manufactured one after another.

In addition, when the drain valve 50 is partially opened during the above process, the opening area is adjusted according to the shape of the molds 1 and 2 and other molding conditions, so as to always maintain optimal heating efficiency, steam consumption, etc. can be selected. Moreover, not only one discharge pipe 5 and drain valve 50 may be installed for one mold, but also a plurality of discharge pipes 5 and drain valves 50 may be installed depending on the amount of steam and cooling water discharged. is also possible.

According to this inventive device configured as described above,
A single exhaust pipe is used to discharge steam, cooling water, etc., and a cylinder is used to move the valve body inside the drain valve, and the opening can be adjusted by changing the air pressure. Since a drain valve is installed, the opening degree of the drain valve can be freely adjusted at each stage of the molding process by selecting three stages: fully closed, partially open, fully open, etc., and a relatively small discharge port is required. When discharging steam, leave the drain valve partially open, and conversely, when discharging cooling water that requires the largest possible outlet, open the drain valve fully.
It is possible to always secure the optimum discharge port area, and is very suitable for effective use of thermal energy and efficiency of the molding cycle. In particular, by adjusting the opening area when the drain valve is partially open, it is possible to easily respond to changes in the amount of discharged steam due to molding conditions, etc., making a significant contribution to saving the amount of steam used and improving heating efficiency. It is something. In addition, compared to a system with two exhaust pipes, one for steam and one for cooling water, the cost of the equipment is lower, and in terms of work efficiency, it is simpler because only one drain valve needs to be operated.

Therefore, it is possible to effectively utilize thermal energy in foam molding and to improve the efficiency of the molding cycle at the same time, and the cost of the equipment is also relatively low, making it suitable for automating the molding process, etc., and can exhibit various excellent effects. .

[Brief explanation of the drawing]

The figures illustrate an embodiment of the present invention, and FIG. 1 is a schematic sectional view, FIG. 2 is a sectional view of the drain valve in a fully closed state, FIG. 3 is a sectional view of the drain valve in a partially open state, and FIG. The figure is a sectional view of the fully opened state. 1, 2... Mold, 10, 20... Steam chamber, 3... Mold cavity, 5... Discharge pipe, 50... Drain valve.

Claims (1)

[Scope of Claims] 1. In an apparatus for performing foam molding by filling a raw material made of expandable thermoplastic resin particles into the cavities of a pair of molds and heating and expanding the raw material with steam, the steam chamber of each mold is A drain pipe is connected to the drain valve, and a drain valve equipped with an opening adjustment mechanism that can freely adjust the opening area is attached to the drain pipe. A foam molding device characterized in that the body is moved by a cylinder and can be adjusted by changing air pressure. 2. The foam molding apparatus according to claim 1, wherein the opening adjustment mechanism of the drain valve is configured so that the opening area of the drain valve can be changed in three stages: fully closed, partially opened, and fully opened. 3 The air pressure changing mechanism consists of two solenoid valves installed in parallel in the air piping to the drain valve, and a pressure regulating valve installed in series with one of the solenoid valves. The foam molding apparatus according to claim 1, wherein the air pressure introduced into the drain valve is changed by operating the valve.