JPS5954007B2 - plastic transport pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in plastic transport pipes, and more particularly to plastic transport pipes for pneumatically transporting pelletized plastics such as polyethylene, polyvinyl chloride, and ethylene-vinyl acetate copolymers. It is.

When manufacturing cables, an extruder is used to coat the outer periphery of the conductor with polyethylene or other plastic.

Plastic is supplied to this extruder via a hopper, and the plastic supplied to the extruder is previously formed into pellets in consideration of ease of handling.

That is, the pellet-shaped plastic that is air-transported to the extruder is softened by the heat inside the cylinder and the frictional heat of the plastic itself, and this softened plastic is coated on the outer periphery of the conductor.

By the way, when transporting pellet-shaped plastics by air, conventionally, metal pipes such as stainless steel, aluminum, iron, copper, etc., or synthetic resin pipes, such as polyethylene, polyvinyl chloride, etc., have been used as plastic transport pipes.

However, according to the conventional transport pipes described above, when transporting plastic pellets, static electricity of several hundred to hundreds of thousands of volts is generated due to friction between the plastic pellets and the walls of the transport pipe.

As a result, when the electric charge stored in the walls of the transport pipes discharges, there is a risk of sparks, fire, explosion, and even electric shock, so it is necessary to ground the pipes.

In addition, according to the above-mentioned conventional transport pipe, the pellet-shaped plastic passing through the pipe is also charged and attracts dust in the air, and when this dust gets mixed into the plastic covering the cable conductor, the cable It has a negative impact on lifespan.

SUMMARY OF THE INVENTION In consideration of the above points, an object of the present invention is to provide an improved transport pipe of this type that can reduce electrical phenomena during transport of pelletized plastics compared to conventional pipes.

In order to achieve the above object, the present invention provides a plastic transport pipe for transporting pelletized plastic by air.
The transportation pipe is configured by alternately connecting charged tubes that are positively charged by being rubbed against the conveying pellet-like plastic and charged tubes that are negatively charged by being rubbed against the conveyed pellet-like plastic. This is a characteristic feature.

In addition, for example, when polyethylene is used as the conveyed pellet-shaped plastic, the above-mentioned conveyed pellet-like Examples of charged tube materials that become negatively charged when rubbed against plastic include polyvinyl chloride, and examples of charged tube materials that become positively charged when rubbed against the conveyed pellet-like plastic include stainless steel and aluminum. etc. can be mentioned.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a partial vertical sectional view of a plastic transport pipe showing an embodiment of the present invention, in which 1a is a stainless steel pipe and 1b is a polyvinyl chloride pipe. It is configured by alternately connecting and arranging vinyl pipes 1b.

In the above configuration, when pellet-shaped plastic (polyethylene in the first experiment) 2 is conveyed by air through the transport pipe 1, it is transported into the first stainless steel pipe 1a, and a negative charge is generated due to friction with the inner wall of the stainless steel pipe 1a. When the charged pellet-shaped plastic 2 is then conveyed into the connected polyvinyl chloride pipe 1b, it is charged with a positive charge due to friction with the polyvinyl chloride pipe 1b, and as a result, at this point Then, it becomes a form in which the negative and positive charges are charged, a so-called neutralized form, and the pellet-shaped plastic 2 becomes completely uncharged.Then, depending on the number of connected tubes 1a and 1b, these phenomena occur. is included.

Therefore, the neutralization of the plastic pellets 2 in the transport pipe 1 is promoted by the positive and negative charges, so the electrical phenomenon of the plastic pellets 2 passing through the plastic transport pipe 1 is effectively suppressed. Ru.

Figure 2 shows a predetermined amount of plastic pellets being air-transported using the transport pipe of the present invention and a conventional transport pipe, respectively, and the amount of static electricity (collector potential FIG. 2 is a diagram of the experimental equipment in a state where the amount of water (by a meter) is being measured.

In this experiment, polyethylene 1801 was used as the pelleted plastic.

In Figure 2, A is a pelletized polyethylene supply tank, B is
is a pellet I-shaped polyethylene transport pipe (diameter 50 mm),
C is pelletized polyethylene transport tank, D is tank C
The hopper is located at the top of the
00kg/h).

[Experimental Example 1] When a polyvinyl chloride pipe is used as the pellet polyethylene transport pipe B, the amount of static electricity was measured by bringing a current collector electrometer close to the pellet polyethylene in the tank C after transportation, and the amount of static electricity was 50 KV. (conventional example).

[Experiment Example 2] As the pellet polyethylene transport pipe B, the amount of static electricity of the pellet polyethylene was measured as in Experiment Example 1 when 4 m of stainless steel pipe was used for the horizontal part and polyvinyl chloride pipe was used for the other part, and the amount of static electricity of the pellet polyethylene was 3QKV. (this invention).

[Experiment Example 3] As the pellet polyethylene transport pipe B, the amount of static electricity of the pellet polyethylene was 15 KV when measured in the same manner as in Experiment Example 1 when 6 m of stainless steel pipe was used for the horizontal part and polyvinyl chloride pipe was used for the other part. (this invention).

[Experimental Example 4] As the pelletized polyethylene transport pipe B, a 10 m stainless steel pipe is used for the horizontal part and a polyvinyl chloride pipe is used for the other part.The amount of static electricity of the pelleted polyethylene is 50V when measured in the same manner as in Experimental Example 1. (this invention).

As described in detail above, according to the present invention, it is possible to provide an improved transport pipe of this type that can reduce electrical phenomena during transport of pelletized plastic compared to the conventional art.

[Brief explanation of the drawing]

FIG. 1 is a partial vertical sectional view of a plastic transport pipe showing an embodiment of the present invention, and FIG. 2 shows pellets transported by the transport pipes of the present invention and a conventional transport pipe, respectively. FIG. 2 is a diagram of an experimental apparatus in a state where the amount of static electricity of plastic is being measured. 1...Plastic transport pipe, 1a...Stainless steel pipe, 1b...Polyvinyl chloride pipe, 2...Pellet-shaped plastic.

Claims (1)

[Claims] 1. In a plastic transport pipe that transports pellet-shaped plastic by air, the transport pipe includes a charged tube that is positively charged by being rubbed against the transported pellet-like plastic, and a charged tube that is negatively charged by rubbed against the transported pellet-like plastic. A plastic transport pipe characterized in that it is comprised of parts in which and are connected alternately.