JPH0776395A - Hopper for powder - Google Patents

Abstract

PURPOSE:To prevent charged powder from sticking to the outlet end of a powder-feeding hopper and prevent the powder from blocking the hopper even after continuous operation over a long period of time by surfacing a damper with a sheet of fluorocarbon resin. CONSTITUTION:Oridinarily as a means of opening and closing a powder- discharge opening of a stainless steel-made powder hopper and provided under the hopper a plate-shaped damper of stainless steel is used which is surfaced by the use of an adhesive, etc., with a sheet of flourocarbon resin (preferably one of polytetrafluoroethylene) having a thickness in the range of 0.2-0.3mm. Statically charged powder can be made more difficult of sticking by using silicone resin for the powder-discharge opening adjoining a conical part of the hopper, specifically at the part where it comes in contact with the fluorocarbon resin of the damper at the discharge opening; in other words, the part forming the powder-discharge opening is formed of silicone resin or such a part formed of stainless steel or aluminum is lined or coated with silicone resin. With pellets which have been statically charged pneumatic conveyance, neither is it easy for them to cause blocking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder supply hopper for supplying resin pellets to a weighing hopper of a resin molding machine, or a grain size of rice, coffee beans, inorganic filler, etc.
The present invention relates to a powder supply hopper for supplying 10 mm powder to a weighing hopper.

[0002]

2. Description of the Related Art In industrial fields such as feed, food industry, resin, and rubber, pipes are transported by air from a large container containing pellets, powders, etc., and supplied to a weighing hopper of a molding machine or a bag filling machine. . For example, the inflation film molding machine shown in FIGS. 3 and 4 will be described. In this inflation film molding machine (1), the thermoplastic resin pellets (c) as a raw material are housed in a large flexible container and are fed by air. Supply from pipe to autoloader,
Weighed, fed a fixed amount to a small hopper, mixed with other powder by a mini mixer, and then supplied to a medium-sized mixing hopper, from this mixing hopper through an idle pipe, a pressure-resistant hose to a suction hopper, The load applied to the pellet damper by the damper that opens and closes the powder discharge port at the bottom of the suction hopper and the balancer load that pushes the damper upwards become unbalanced, and when the pellet load increases, the damper goes down and feeds. A fixed amount of pellets is supplied to the hopper (2).

For the pellets (c) stored in the supply hopper (2), the load cell (3) operates in accordance with the take-up speed of the inflation resin film according to the instruction of the computer, and the thermoplastic resin (c) is discharged. Are automatically fed into the weighing hopper (4). The extruder (5) has a built-in screw (7) that is driven to rotate by a screw motor (6), and uses the thermoplastic resin (c) supplied from the weighing hopper (4) as a molten resin to move upward from the tip. Extrude into. A blow head (9) incorporating an annular molding die (d) is attached through a direct connecting pipe (8) in the vertical direction of the tip of the extruder (5), and air is blown into the extruded molten resin to form a cylinder. A supply / exhaust pump (12) is provided in the blow head (9) via a valve pipe (11) having an electromagnetic bubble (10) to form a bubble (e).
Are connected.

An air cooling ring (13) is arranged above the blow head (9), and the cylindrical bubble (e) is expanded and expanded by the air supplied from the cooling blower (14).
To be cooled. The cylindrical bubble (e) is a guide plate (15),
The inflation resin film (f) is folded into a two-layer sheet by the take-up rolls (17) and (17) guided by (15) and rotationally driven by a tension motor. After the film width of the inflation resin film (f) is measured by the width sensor (19) of the film width measuring device (18), the guide rolls (20), (2).
0) and (21), and is wound around the paper tube (g) which is inserted and held in the holding rod (23) of the film winder (22).

Here, in the case of producing a bag forming film, the inflation resin film (f) is wound around a paper tube (g) in a state of being folded into a two-layer sheet, but a wrap film or a stretch film is used. In the case of manufacturing the same, the inflation resin film (f) is divided by the cutter into a required number of strips in the width direction and then inserted into and held by the holding rod (23) of the film winder. g), (g), and (g). These hoppers are usually made of stainless steel. Over the past ten years, resin processing manufacturers have also possessed many molding machines with 5 to 20 machines, and the supply of pellets to the weighing hopper is 50 to 50 machines.
It is designed to be carried out by using a long empty pipe having a length of 200 m. When the pellets are transported in air, the pellets are charged with static electricity, causing the pipes to be squeezed (particularly at the joints at right angles to the pipes) and causing clogging in the hopper.
There is a problem that resin pellets are not supplied to the weighing hopper.

In order to solve this, a Teflon coating having excellent slipperiness is applied to the inner surface of the pipe or the inner surface of the cone portion of the hopper (Japanese Patent Laid-Open Nos. 50-127951 and 5).
2-96786 gazette) or carbon powder-containing resin for static elimination, or static elimination equipment for spraying ion air charged with opposite ions, or compressed air is supplied to the cone portion of the hopper with many clogging. It has been proposed and implemented that such equipment be provided. However, even if such a means is applied, it cannot be said that the pellets are completely clogged, and particularly in a small suction type hopper, clogging occurs once a day, and the operation of the molding machine is stopped. It was necessary to clean the hopper or hit the outside of the hopper with a hammer so that the resin pellets were supplied. The reason for this is that in the suction hopper shown in FIG. 5, the resin pellets are depressurized in the suction hopper by the operation of a suction pump (not shown), and the pellets are supplied from the mixing hopper into the suction hopper through the pellet injection port. Although the pellets are supplied to, the charged pellets adhere to the end of the discharge port of the suction hopper if the charge of the pellet is large, and the discharge port of the damper is not completely closed.

If charged pellets are attached to the discharge end of the suction hopper and a gap is created between the damper and the discharge port,
Since the outside air is sucked into the suction hopper through this gap, the degree of decompression (vacuum degree) in the suction hopper does not drop easily, and the suction force is insufficient and pellets are not supplied to the suction hopper. When the supply of pellets to the supply hopper (2) is stopped and the supply of pellets to the molding machine (1) is interrupted, the molding machine runs idle,
The film is no longer formed. Recently, unmanned robots in molding factories are being considered, but this clogging causes the need for human monitoring, and how to solve this is an issue.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hopper for supplying powder which does not cause clogging of the powder for one month or more even when continuously operated.

[0009]

[Means for Solving the Problems] In the powder supply hopper, the inventors of the present invention have attached a discharge port end due to charging of powder,
As a result of various studies on the incomplete closing of the damper discharge port due to this, as a result of lining the surface of the damper of the hopper with a fluororesin sheet, the charged powder did not adhere to the end of the discharge port. We have found that the outlet can be completely closed, and when the powder outlet of the damper of the powder outlet following the cone of the hopper, which is in contact with the fluororesin sheet, is made of silicone resin. Has completed the present invention by finding that the charged powder does not adhere to the end of the discharge port.

That is, the present invention provides a powder supply hopper in which the surface of a damper provided at the bottom of a metal powder supply hopper for opening and closing the powder discharge port is lined with a fluororesin sheet, and at this time, the hopper is provided. However, there is a screen that does not allow powder to pass through but a gas through the top, a suction passage is provided from the lid part above this screen, and a powder injection port is provided on the side wall of the hopper. The above-mentioned powder supplying hopper which is a mold hopper,
Provided is a powder supply hopper in which a powder discharge port of a damper of a powder discharge port following a cone portion of the hopper, which is in contact with a fluororesin sheet, is made of a silicone resin. The powder supplied by the hopper of the present invention, polyethylene, polypropylene, polyamide,
Resin powder such as polycarbonate, natural rubber, SBR, N
Rubber powder such as BR, grains such as beans, wheat and rice, coffee beans,
Examples include luxury items such as black tea, and feeds such as corn, oats, and knees.

The housing of the hopper, the cone portion and the powder discharge port are usually made of stainless steel, but aluminum,
Copper, galvanized iron, etc. may also be used. In addition, the damper in the present invention is a plate-shaped body made of stainless steel or the like and has a thickness of 0.2 to 3
A fluororesin sheet in the range of mm is lined with an adhesive or the like. The fluororesin used in the present invention includes polytetrafluoroethylene (Teflon, trade name), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene /
Hexafluoropropylene copolymer, tetrafluoroethylene / ethylene copolymer, polychlorotrifluoroethylene, polyvinylidene fluoride, tetrafluoroethylene / hexafluoropropylene / perfluoroalkyl vinyl ether copolymer, and the like. Fluoroethylene is preferred.

The effect is further improved when the powder discharge port of the damper of the powder discharge port following the cone of the hopper is in contact with the fluororesin sheet and is made of silicone resin. That is, the powder discharge port is made of silicone resin, and the powder discharge port made of stainless steel or aluminum is lined or coated with silicone resin. As the silicone resin used at that time, silicone rubber such as poly (phenylsiloxane), poly (methylhydrogensiloxane), poly (fluorosilicone), phenylsiloxane / methylvinylsiloxane copolymer, and dicumyl of this silicone rubber are used. Examples thereof include those crosslinked with a crosslinking agent such as peroxide and tertiary butyl peroxide, those obtained by curing a silicone resin (varnish), and the like.

[0013]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. Example of film production An inflation film was produced under the conditions of the following (Example 1) and (Example 2) using the suction hopper of the material shown in Table 1 in the inflation film production apparatus shown in FIGS. Table 1 also shows the period during which clogging occurs. (Example 1) Low-density polyethylene (density: 0.923 g / c
m, MFR at 190 ° C .: 0.3 g / 10 minutes, crystallinity: 50%) was kneaded at 190 ° C. using an extruder having a bore size of 50 mm and L / D: 25, and supplied to an annular forming die. hand,
Die temperature: 190 ° C, blow ratio: 2.5, take-up speed: 6
Inflation molding at m / min gives a wall thickness of 35
A μm resin film was produced.

(Example 2) Ethylene 4-methylpentene-
1 copolymer resin (density: 0.910 g / cm ³ , 190
MFR at 3.6 ° C: 3.6 g / 10 minutes, crystallinity: 36%)
(A) was kneaded at 175 ° C. using an extruder having a diameter of 65 mmφ and L / D: 25, while an ethylene / vinyl acetate copolymer resin (vinyl acetate content: 15% by weight, 190 ° C.) was used.
MFR at 2.0 g / 10 min) 97.1% by weight, diglycerin oleate (Riken Vitamin Co., Riquemal 0-
71-D) 2.9% by weight of the resin composition (B) was used at an extruder having a diameter of 50 mm and an L / D of 25 to 160 ° C.
Kneading with, and supplying both to one annular three-layer die,
A composition (B) containing an ethylene-vinyl acetate copolymer resin as a main component on both surfaces of an intermediate layer made of the resin composition of (A)
Die temperature: 175
C., blow ratio: 3.5, take-up speed: 20 m / min.
m / 5 μm / 3 μm) resin film was produced.

[0015]

[Table 1]

From Table 1, it was found that in Example 3 in which the damper was lined with 1 mm thick Teflon, the period during which clogging occurred was considerably prolonged, and the exhaust port was made of silicone resin to further You can see that it is getting longer.

[Brief description of drawings]

FIG. 1 is a sectional view of an example of a suction hopper of the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a schematic view of an inflation molding device used in the present invention.

FIG. 4 is a schematic view of a pellet supply portion of the inflation molding apparatus of FIG.

FIG. 5 is a schematic view when a conventional suction hopper is clogged.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Nishihara Tamotsu, 1000, Kawajiri-cho, Yokkaichi-shi, Mie Mitsubishi Yuka Engineering Co., Ltd. Yokkaichi branch office (72) Inventor, Toshihiko Ichioka, 1000, Kawajiri-cho, Yokkaichi-shi, Mie Mitsubishi Petrochemical Engineering Co., Ltd. Yokkaichi branch office

Claims (3)

[Claims] 1. A powder supply hopper characterized in that the surface of a damper for opening and closing a powder discharge port provided at the bottom of a metal powder supply hopper is lined with a fluororesin sheet. 2. The hopper is provided with a screen which does not allow powder to pass therethrough but allows gas to pass therethrough, a suction passage is provided from a lid portion provided above the screen, and a powder injection port is provided on a side wall of the hopper. The powder supply hopper according to claim 1, which is a suction type hopper having a structure provided. 3. The hopper for powder supply according to claim 1, wherein the powder discharge port of the powder discharge port following the cone portion of the hopper, which is in contact with the fluororesin sheet of the damper, is made of silicone resin. .