JPH0548116Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a device for continuously collecting powder samples to be tested to be transferred to a melt indexer MI meter.

Prior Art In order to control the quality of thermoplastic materials or to supply fluid plastics that meet customer needs, the thermoplastics to be tested are melted under conditions of temperature and pressure determined by their properties. A thermoplastic is extruded through a die of specified length and diameter, and the mass of plastic extruded in 10 minutes of extrusion time is calculated as the melt index.
It is stipulated by JIS etc. to be calculated as MI value. In contrast to such discontinuous testing methods, there is an MI meter that tests in a continuous process. This method involves converting the MI value from the product of the density and the rotation speed of a metering pump whose rotation speed is controlled to maintain a constant pressure difference over a predetermined length of the sample into a thin tube. As shown in FIG. 2, the powder is transferred into the tank 1 in the form of thermoplastic powder by a transfer means (not shown). As a result, the plastic powder 2 is piled up in the closed space inside the tank 1 as shown in the figure. Inside this pile of plastic powder is a transfer pipe 3 that has a funnel-shaped opening to receive and drop the plastic powder, and is transferred to an MI total 5 by a mini extruder 4 having a screw driven by an electric motor. be done.

Problems with the prior art In the above-mentioned prior art, plastic powder is transferred by gravity, but the powder pressure at the funnel-shaped opening is small, powder friction is large, and the transfer pipe 3 Because it is relatively long and sloped, the flow resistance is large and it may not fall.
A problem arose in that continuous measurements using the MI meter were not possible. In addition, since the particles were small, they were easily oxidized and did not show correct MI values.

Means to Solve the Problems The present invention has a high powder pressure, allows for continuous transfer using a screw to constantly reduce the resistance to powder collection, and also prevents oxidation using inert nitrogen gas. Ivy.

Specific Example Figure 1 is a diagram for explaining one embodiment of the present invention. In the diagram, parts having the same functions as the conventional example shown in Figure 2 are designated by the same numbers as in Figure 2. It is attached. Therefore, in the present invention, a cylindrical body 30 having a probe 31 extending into the tank is disposed perpendicularly to the tank wall surface by means of attachment means of a flange 35 on the tank wall surface, and the cylindrical body 30 is connected to the outside of the tank 1. An electric motor 36 is arranged to rotate a screw 33 coaxial with the probe 31. Powder is collected through powder sampling port 32.
The powder is collected by a screw 33, and a plurality of powder sampling ports 32 are opened around the circumference of the probe 31, and a large opening area is formed by utilizing substantially uniform powder pressure. Note that the powder sampling ports 32 opened in this manner may be formed in multiple rows around the circumference of the probe, or may be formed in any number of rows as required. The powder transferred by the screw 33 reaches the outside of the tank of the cylindrical body 30 and falls through a conduit 34 that communicates orthogonally with the cylindrical body 30 . At this time, nitrogen gas is ejected from the upper part of the conduit 34 from a nitrogen gas source (not shown) via the valve 6 and the pressure regulating valve 7 in order to prevent oxidation of the powder. The plastic powder thus dropped is fed under pressure to the MI meter 5 by the mini extruder 4 as explained in the conventional example.

Effects In the present invention, the powder pressure is applied evenly near the powder sampling port 32 of the probe 31, and the opening area is also widened, so the flow resistance is small.Furthermore, since the powder is fed under pressure by the screw, the powder is The flow is continuously transferred without stopping. Note that since the continuously transferred powder is in an inert gas atmosphere such as nitrogen gas, it maintains a chemically stable form and can continuously measure MI values using MI type 5.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of the powder sample collecting device of the present invention, and FIG. 2 is a diagram showing the conventional configuration. 1...Tank, 2...Plastic powder, 30
... Cylindrical body, 31 ... Probe, 32 ... Powder sampling port, 33 ... Screw, 5 ... MI meter.

Claims (1)

[Scope of utility model registration request] A tank for storing a resin powder sample, a cylindrical body that is installed horizontally in the tank through a wall surface of the tank and has a plurality of powder sampling ports perforated in the axial and circumferential directions; a screw disposed in the axial direction for rotating and conveying the powder sample inside the cylindrical body toward the outside of the tank; a vertical conduit disposed outside the tank and communicating with the cylindrical body; a horizontal mini-extruder that transfers the powder sample conveyed through the tube and the conduit to the melt indexer, and an inert gas supply means that pumps an inert gas to the tube and the conduit and the mini-extruder. A powder sample collection device in a melt indexer, characterized by comprising: