JPH0568610U - Raw material distribution hopper equipment for foam molding machine for polyolefin resin - Google Patents

Abstract

(57) [Summary] [Structure] An air venting device is provided at a raw material inlet 2 provided at the upper center of a hopper body 1 having a horizontal horizontal cross section, and a plurality of hopper bodies 1 are provided at the lower end of the peripheral wall surface. In a raw material distribution hopper device in a foam molding machine having a raw material distribution port 4, an opening / closing device having an independent open / close valve 5 is provided at the raw material distribution port 4 so as to move up and down in the hopper body 1. Is provided, and the frustoconical baffle plate 6 is provided at the lower part of the inner peripheral wall of the hopper body 1.
And a cylindrical spacer 8 having a conical head at the center of the bottom of the hopper body 1. [Effect] The distribution of the pre-expanded granules in the hopper for a small amount of time is provided to provide a uniform molded product with no variation in weight.
In addition, malfunction troubles are prevented.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hopper device for distributing raw materials in a foam molding machine for polyolefin resin, and more specifically, it provides a uniform molded product having a small distribution of pre-expanded granule residence time in the hopper and no variation in weight. In addition, the present invention relates to a hopper device for raw material distribution without trouble such as malfunction.

[0002]

[Prior Art]

 Generally, in forming pre-expanded polyolefin resin particles (hereinafter, abbreviated as a raw material), as a pretreatment, a constant internal pressure is applied to the raw material by using an inorganic gas by a method described in JP-B-51-22951. The raw material obtained at all is stored in a pressure hold tank, blown into the raw material distribution hopper whenever necessary for molding, sent from the raw material distribution hopper into the mold cavity through the raw material filling device, heated, A method of manufacturing by cooling is used.

It is difficult to obtain a foamed raw material having a uniform specific gravity and size due to variations in the raw material before pre-foaming and variations in the raw material in the pre-foaming step. Thus, the raw material blown to the raw material distribution hopper is agitated by the blown air to be separated into the one with large specific gravity and the one with small specific gravity, and the heavy one is accumulated near the raw material inlet and The larger the particle size, the greater the particle size, and the larger the particle size, the more distant it rolls.

Therefore, the specific gravity of the raw materials varies depending on the location in the distribution hopper. However, as shown in FIGS. 1 and 2, the conventional distribution hopper has a rectangular cross section on the upper surface of the hopper body (21). Since the raw material feed-in port (22) is provided and a plurality of distribution ports (23) for taking out raw materials are provided in series on the bottom surface, a difference in specific gravity occurs in the raw materials depending on the position of the raw material distribution port (23), and the raw material is directly transferred to Since it is sent into the mold cavity, the weight of the molded product varies, and the uniformity of the molded product is impaired.

Further, when the raw material supplied to the hopper is left in the atmosphere, the gas impregnated under pressure (mainly air is large) dissipates into the atmosphere, and it takes several days to dissipate completely. The time (hereinafter abbreviated as hot life) during which the internal pressure effective for molding (usually 2.8 to 2.0 atm) can be maintained under atmospheric pressure is 15 to 30 minutes. Therefore, it is necessary that the raw material does not cause a residence time distribution in the hopper, and the above conventional hopper cannot be used because dead space is generated.Therefore, there is no residence time distribution, that is, a hopper having a structure that causes piston flow. Needed.

In order to solve the above problems, Japanese Patent Publication No. 59-51891 proposes a hopper device as shown in FIGS. 3 and 4. In these figures, (32) is a hopper body, the upper part of which is formed into a cylindrical shape and a raw material inlet (32) is provided at the center of the upper surface, and the lower part is formed into an inverted conical shape, and the central part of the bottom surface is A plurality of raw material distribution ports (33) are arranged concentrically with respect to the raw material feed port (32) at appropriate intervals. (34) is an opening / closing device for the distribution port (33) arranged on the lower surface in the vicinity of the raw material distribution port (33), and is a disc-shaped rotary shutter having a through port (35) corresponding to the distribution port (33). (36) is rotated by the central shaft (37) to open and close the distribution port (33). Reference numeral (38) is a support body of the rotary shutter (36), and a through hole (39) corresponding to the raw material distribution port (33) is provided. Reference numeral (40) is a blowback air outlet provided in the hopper body (31), and reference numeral (41) is an air venting device provided in the raw material inlet (32).

However, there is a malfunction of the shutter (36) as a problem related to the structure of the hopper. That is, the shutter (36) is located between the raw material distribution port (33) and the communication port (39) and connects or disconnects the raw material distribution port (33) and the communication port (39). A 2 mm metal plate is used. This thin plate is because the raw material of the contents is light (maximum about 2 kg) and it is not used under pressure. Due to the thin plate of the shutter (36), it may be bent during processing and assembly, deformed by the air flow when the raw material is flowing out, or caught in the raw material between the shutter (36) and the distribution port (33). There is an inevitable feeling of trouble. When the raw material is blown back, the raw material is blown back to the hopper body (31) through the through hole (39), the shutter (36) and the raw material distribution port (33). In order to move the raw material and secure a space to store the blow-back raw material, the raw material is blown back and compressed while blowing air from the raw material distribution port. This causes a bridge near the raw material distribution port (33) to cause a blowback failure, which causes a hose (not shown) in the filling device to be blocked, causing a defective filling of the raw material into the mold.

[0008]

[Problems to be solved by the device]

 The present invention provides a raw material distribution hopper device that solves the above problems.

[0009]

[Means for Solving the Problems]

 The inventors of the present invention have arrived at the present invention as a result of earnest research in order to solve the above-mentioned problems in view of the actual situation. That is, according to the present invention, an air venting device is provided at a raw material inlet provided in the upper center of a hopper body having a horizontal horizontal section, and a plurality of raw material distributing ports are provided at a lower end portion of a peripheral wall surface of the hopper body. In a hopper device for raw material distribution in a foam molding machine, an opening / closing device having an independent opening / closing valve is provided at the raw material distribution port, and a powder level gauge having a structure capable of moving up and down in the hopper body is provided. Foam molding for polyolefin resin characterized in that a truncated cone-shaped baffle plate is provided in the lower part of the inner peripheral wall of the hopper body in the opposite direction, and a cylindrical spacer having a conical head is provided in the center of the bottom of the hopper body. The content of the hopper device for material distribution in the machine is the content.

Referring to the drawings showing an embodiment of the present invention, FIG. 5 is a partially cutaway front view, and FIG. 6 is a sectional view taken along line CC of FIG. In these figures, a raw material inlet (2) is provided in the upper center of a hopper body (1) having a horizontal horizontal cross section, and a plurality of raw material discharge ports are provided at the lower end of the peripheral wall surface of the hopper body (1). The outlet (3) is provided, and the raw material distribution port (4) is provided outside the outlet (3). An on-off valve (5) is arranged between the raw material discharge port (3) and the raw material distribution port (4). A frusto-conical baffle plate (6) is provided around the lower part of the inner wall of the hopper body (1), and a plurality of baffle plates (6) including the lower part of the baffle plate (6) are provided on the peripheral wall of the hopper body (1). An air vent hole (7) is provided as appropriate. The air vent hole (7) is composed of a wire mesh, a perforated plate, etc., and is configured so that only the air is discharged to the outside of the hopper without passing the foamed particles. A spacer (8) having a conical head is provided at the center of the bottom of the hopper body (1), a plurality of air vent holes (7) are provided on the peripheral wall of the spacer (8), and air is provided at the bottom. An outlet (9) is provided. (10) is a powder level gauge, (11) is an air venting device provided above the raw material inlet (2), and (12) is a raw material outlet for extracting the raw material at the end of molding.

In the above, the spacer (8) plays a role of preventing the raw material from stagnating in the hopper body (1), particularly in the central portion. If the spacer (8) is not provided, originally, the polyolefin foam particles have poor fluidity by themselves, so that they are retained in the central portion of the bottom of the hopper body, which causes the above-mentioned suitable hot life. It can be difficult to meet requirements.

When the baffle plate (6) blows back, the raw material is blown back into the hopper body (1) through the distribution port (4) together with the excess air from the mold. It has a role to secure a space for receiving. That is, since the raw material supplied from the raw material inlet (2) does not flow into the triangular space formed between the baffle plate (6) and the peripheral wall of the hopper body (1), it is always constant. The space is secured and the raw material blown back can be effectively received.

The powder level gauge (10) increases the power required for stirring when the stirring blade (10a) comes into contact with the raw material, and detects the increase in power at this time to inform the raw material level. Generally, the stirring shaft is often mounted horizontally, but in the above example, it is mounted vertically. By installing the stirring shaft vertically, the position of the stirring blade (10a) can be freely adjusted up and down, which allows only the raw material required for one shot of the mold to be received in the hopper, and the stagnant time of the raw material can be reduced. It is possible to shorten the length and prevent a decrease in the internal pressure of the raw material.

The air vent device (11) is made of a wire net or a porous plate, and in the mixed flow of the air blown from the inlet (11a) and the raw material, the air is discharged to the outside of the device (11). It is configured such that only the raw material is discharged and naturally dropped into the hopper body (1) through the raw material inlet (2).

As the on-off valve (5), a known valve suitable for granules is used, but among them, a sluice valve or a butterfly valve whose actuating valve is opened and closed by compressed air is preferable. The opening and closing of this is configured so that it can be operated remotely.

Explaining an example of use of the device of the present invention shown in FIGS. 5 and 6, the raw material blown from a hold tank (not shown) enters the air vent device (11), and the air is discharged to the outside. Only the raw material is discharged and falls into the hopper body (1) through the raw material inlet (2). The dropped raw material is distributed almost evenly around the spacer (8) along the conical head of the spacer (8) and deposited. The accumulated raw material is opened by operating the on-off valve (5), guided to the raw material filling device (not shown) through the raw material discharge port (3) and the raw material distribution port (4), and the mold cavity is passed through the device. Filled inside. When the filling is completed, the raw material is blown back into the hopper main body (1) together with the excess air from the mold, and the air is blown out into the air vent hole (7) provided in the peripheral wall of the hopper main body (1), especially the obstacle. It is released to the outside through an air vent hole (7) provided in the lower part of the friction plate (6), and partly to the outside through an air vent hole (7) and an air exhaust port (9) provided in the peripheral wall of the spacer (8). The raw material is discharged smoothly to the blow-back raw material accommodating portion by the triangular space formed between the baffle plate (6) and the peripheral wall of the hopper body (1).

FIG. 7 shows another embodiment of the device of the present invention, in which an on-off valve is not used and a crane-shaped raw material distribution port (4) is provided. Such a structure is effective when the blowback operation is not required, and the device can be made simple and inexpensive. The crane-shaped raw material distribution port (4) must be installed at an angle so that raw material does not flow out. For example, as shown in the figure, a structure in which the surface is directed upward by approximately 45 ° and further downward by approximately 90 ° is illustrated.

[0018]

【Example】

 Hereinafter, the present invention will be described in more detail with reference to Experimental Examples, Examples, and Comparative Examples, but the present invention is not limited thereto.

Experimental Example 1 Using foamed granules (density 50 g / l) made of an ethylene-propylene random copolymer having an ethylene content of 4.5% by weight, changes in the internal pressure of the foamed granules were observed. The results are shown in Table 1.

[0020]

[Table 1] From the results shown in Table 1, the internal pressure of the foam particles decreases with time, and the hot life is preferably about 30 minutes.

Example 1, Comparative Example 1 A conventional rectangular hopper shown in FIGS. 1 and 2 (Comparative Example 1) and a cylindrical hopper of the present invention shown in FIGS. 5 and 6 (Example 1) are used. The occurrence rate of defective products was observed by using the expanded beads used in Experimental Example 1. Using hoppers each having an actual volume of 150 liters, molding was performed for 3 hours in each hopper, and 144 molded articles were molded. In the determination of defective products, the so-called "out-of-shape" with poor surface elongation was determined to be defective. The results are shown in Table 2.

[0022]

[Table 2]

Examples 2 to 3 and Comparative Example 2 Using the hopper used in Example 1 and Comparative Example 1, and using the expanded granules (density 15 g / l) made of an ethylene-propylene random copolymer with an ethylene content of 3%, Molded bodies were prepared for each of the three hoppers in the hopper of Example 1 in which no air venting device was installed, and the weight variation of the molded bodies was measured. The molded body had a long side of 1,200 mm, a short side of 150 mm, and a height of 150 mm, and the average weight was 800 g. The results obtained are shown in Table 3.

[0024]

[Table 3]

[0025]

[Effect of the device]

 As described above, the present invention has many advantages as described below, and its industrial utility is extremely great. By providing the raw material inlet at the center of the upper part of the hopper body with a horizontal horizontal cross section, and by providing multiple raw material distribution ports at the lower end of the peripheral wall surface of the hopper body, the raw material comes close to the piston flow, Therefore, the distance from the raw material feed port to each raw material distribution port becomes constant, and the raw material in the hopper body is uniformly fed to the raw material distribution port, and as a result, a predetermined hot life is maintained and the obtained molding is obtained. As there is no variation in the weight of the product, it is possible to obtain a uniform molded product.

By disposing the air venting device at the raw material inlet of the hopper body, it is possible to more effectively suppress the variation in the weight of the molded product.

By disposing a spacer at the center of the bottom of the hopper body, the raw material falling from the raw material inlet can be evenly distributed in the vicinity of the raw material distribution port to prevent the raw material from staying in the central portion of the hopper. That is, variations in the residence time distribution of the raw material are prevented, and as a result, the internal pressure of the raw material is stable, and a compact having a stable size is provided.

By providing the baffle plate, the blowback operation is effectively performed, and the blown back raw material can be smoothly received.

By installing the powder level meter vertically adjustable, the position of the powder level meter blade can be freely changed, and only the raw material amount necessary for one shot of the mold can be received in the hopper, As a result, the residence time can be made to be the minimum necessary, and the internal pressure of the raw material can be prevented from lowering.

Since the opening / closing device having an independent opening / closing valve is provided at each of the raw material distribution ports, the deformation of the shutter due to the air flow at the time of the raw material outflow in the conventional rotary shutter, the raw material between the shutter and the distribution port. Malfunctions due to biting etc. are eliminated.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a conventional rectangular hopper.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a longitudinal sectional view showing a conventional cylindrical hopper.

4 is a sectional view taken along line BB in FIG.

FIG. 5 is a vertical sectional view showing an embodiment of the hopper device of the present invention.

6 is a cross-sectional view taken along line CC of FIG.

FIG. 7 is a vertical sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 1 Hopper Main Body 2 Raw Material Inlet 3 Raw Material Discharge Port 4 Raw Material Distribution Port 4'Raw Material Distribution Port 5 Open / Close Valve 6 Frustum-Shaped Conical Baffle Plate 7 Air Venting Hole 8 Spacer 9 Air Discharge Port 10 Powder Level Meter 11 Air Venting Device 12 Raw Material Venting Exit 13 damper

Claims (2)

[Scope of utility model registration request] 1. An air venting device is provided at a raw material inlet provided at the center of an upper portion of a hopper body having a horizontal horizontal section, and a plurality of raw material distributing ports are provided at a lower end portion of a peripheral wall surface of the hopper body. In a raw material distribution hopper device in a foam molding machine, an opening / closing device having an independent opening / closing valve is provided at the raw material distribution port, and a powder level gauge having a structure capable of moving up and down in the hopper body is provided. A hopper device for raw material distribution in a foam molding machine for polyolefin resin characterized in that a frusto-conical baffle plate is provided in the lower part of the peripheral wall in the opposite direction and a cylindrical spacer having a conical head is provided in the center of the bottom of the hopper body. .. 2. The apparatus according to claim 1, wherein a plurality of air vent holes are provided in a cylindrical spacer having a hopper body and a conical head.