JPH0712915Y2 - Piston for flow tester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to the structure of a piston of a capillary extrusion type flow tester used for flow tests of thermoplastic materials, thermosetting materials and the like.

B. Conventional technology A tester used for flow test measurement of thermoplastic resin, etc. extrudes through a die installed at the exit of the cylinder while heating the sample filled in the cylinder, and its extrusion speed (displacement of piston per unit time The flow rate, shear rate, shear stress, viscosity, flow characteristics, etc. of the sample are obtained from (amount).

In this type of testing machine, as shown in FIG.
The piston P is inserted from above the sample T therein and pressurized by a load device (not shown).

C. Problem to be Solved by the Invention In this case, the relationship between the piston P and the inner surface of the cylinder S is essentially that the piston P is located concentrically with the cylinder S as shown in FIG. , It moves up and down by the stroke. In the case of FIG. 3, the difference between the diameter d of the piston P and the inner diameter D of the cylinder S, that is, the gap is uniform around the circumference. Usually this uniform gap is
It is about 20 microns, and the sample T rarely leaks from this gap.

However, in actual use, as shown in FIG. 4, the piston P is biased to one side and contacts at the point K, and the above-mentioned gap has a value nearly doubled. In this case, the sample T in the sample leaks above the piston P, and therefore the displacement amount of the piston P and the extrusion amount of the sample T from the die Y do not correspond to each other, and accurate measurement of test data cannot be expected. At the same time, the piston P is in contact with the inner surface of the cylinder S, and the inner surfaces of the piston and the cylinder are scratched, causing a problem in durability.

D. Means for Solving the Problems In order to solve the above problems, the present invention adopts the following configuration.

That is, the piston of the testing machine according to the present invention includes an annular seal member and an annular guide member that are spaced apart from each other in the axial direction. Moreover, the outer diameter of the annular seal member is adjustable.

E. Action The annular guide member keeps the piston concentric with the cylinder. On the other hand, the annular sealing member always prevents the sample from leaking to the top.

F. Embodiment FIG. 1 shows an embodiment of the present invention, in which only the piston is shown in a vertical section.

In the case of the illustrated example, the main body of the piston is composed of the lower cylindrical body 1 and the upper cylindrical body 2. The lower cylindrical body 1 has a small diameter portion 1M formed at the upper end thereof, while the upper cylindrical body 2 has a step portion inwardly of the middle thereof, and the lower portion thereof has a small diameter portion 2S inserted into the lower cylindrical body 1. Further, a screw portion 2N is provided inwardly above.

Both cylinders 1 and 2 are assembled as shown in the drawing, and an annular guide member 6 is inserted into the small diameter portion 1M of the cylinder 1. The member 6 is made of, for example, a tetrafluororesin material.

Reference numeral 4 denotes a lower frame body, the upper protrusion 4L of which is inserted into the inner diameter of the lower cylinder body 1. The protrusion 4L is provided with a female screw 4N, and the screw rod 5 inserted into the upper cylinder body 2 is The lower screw part is screwed. The lower frame 4 has a lower end flange portion equal to the outer diameter of the lower cylindrical body 1, and has an intermediate diameter portion 4M between it and the projecting portion 4L. An annular seal member 7 is fitted into the intermediate diameter portion 4M as shown in the figure. The annular seal member 7 is pressed against the surfaces of the cylindrical body 1 and the frame body 4, and the pressure contact state is changed by rotating the screw rod 5 and vertically adjusting the frame body 4 with respect to the cylindrical body 1. The outer diameter changes. The seal member 7 is also made of, for example, a tetrafluororesin material. Therefore, when the outer diameter of the annular seal member 7 becomes smaller due to wear over a long period of time, the screw rod S can be adjusted to correspond to the inner diameter of the cylinder S, which is the outer diameter of the seal member 7, at a constant gap. 8 is a screw rod 5 and a cylindrical body 2
It is a washer interposed between the stepped portions 2D of.

On the other hand, a screw frame body 3 is screwed into the upper screw portion 2N of the upper cylinder body 2. 3L is a load member that is in contact with the upper side of the screw frame body 3.

The features of the present invention have been described in detail above, but are not limited to the above and the illustrated examples. The materials of the seal material and the guide material are not limited to the tetrafluororesin material. The outer diameter adjusting means of the sealing material is not limited to the illustrated example. Further, it is not a condition that the entire piston be a divided body as shown in the figure. This idea encompasses all of these.

G. Effect of the Invention The piston for the flow tester of the invention is as described above, and the piston is always located in the center of the cylinder due to the seal member and the guide member, and the test is performed with high accuracy without leaking the sample. And the inner surface of the cylinder,
Good durability with no scratches on the piston.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a piston for a flow tester according to the present invention, FIG. 2 is a view showing a piston of a conventional flow tester, and FIGS. 3 and 4 are planes AA in FIG. It is a sectional view showing. 1 ... Lower cylinder, 2 ... Upper cylinder, 3 ... Screw frame, 4 ... Frame, 5
… Screw rod, 6… annular guide member, 7… annular seal member. 8… washer

Claims (1)

[Scope of utility model registration request] 1. A softened sample is extruded through a die attached to the outlet side of the cylinder by heating the sample filled in the cylinder while loading it through a piston inserted in the cylinder, and extruding at that time. In a tester for speed, sample flow rate, shear rate, shear stress, viscosity, etc., an annular seal member and an annular guide member are attached to the piston at a constant interval in the axial direction, and the outer diameter of the annular seal member is adjusted. A piston for a flow tester, which is configured to be capable of performing.