JPH0119076Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a flow tester for measuring the melt viscosity of plastics, etc., and more specifically relates to a pore extrusion type flow tester.

Generally, in this type of flow tester, a sample is inserted into a cylinder with a heating function and an orifice at the bottom end to melt it, and the molten sample is pushed out from the orifice under a constant load by a plunger to measure the flow rate. Measurements are taken over time to determine viscosity, etc. Conventionally, as a loading mechanism for applying a constant load to a plunger, a mechanism using a lever principle, which is considered to be most suitable for generating a constant load, has been adopted. That is, a weight is suspended from the other end of a lever that is rotatable with one end as a fulcrum, and a plunger is engaged with the intermediate part of the lever via a press joint, etc., and the weight is adjusted to the plunger according to the weight of the weight and the lever ratio. Apply a constant load. In such a loading mechanism, the lever tilts in response to the downward displacement of the plunger as the sample flows out of the cylinder, but at this time, if the lever system has a large mass, the inertia force due to the acceleration of the tilt will be applied to the plunger. The amount of displacement of the plunger was also restricted because the load value changed with the slope.

The present invention was developed in view of the above, and aims to provide a flow tester that can always press a sample with a constant load by eliminating the influence of inertial force due to the acceleration of lever tilt and changes in load value due to lever tilt. do.

The feature of the present invention is that the above-described amount of inclination of the lever is detected and the cylinder is driven in the vertical direction so that the amount of inclination becomes zero.

Hereinafter, embodiments of the present invention will be described based on the drawings.

The drawing is a configuration diagram of an embodiment of the present invention. Heater 1
A plunger 2 is slidably fitted into a cylinder 1 having an orifice 1b at its bottom. A load shaft 4 is attached to the plunger 2 via a press joint 3, and the load shaft 4 is supported by slide bearings 5, 5 so as to be slidable in the vertical direction, and is engaged with a lever 6. It is designed to move up and down as the lever 6 is tilted. The lever 6 is rotatable around a fulcrum 6a provided at one end, and the weight of a weight 7 suspended at the other end pushes the plunger 2 downward via the load shaft 4 and press joint 3. do. Further, a tilt amount detector 8 for detecting the tilt amount of the lever 6 is provided near the weight hanging portion of the lever 6, and its output is introduced into a motor control circuit 9. This tilt amount detector 8 can be constructed, for example, from a differential transformer or the like. Note that the lever 6 is provided with a balance weight 10 that applies a force such that the load on the plunger 2 becomes zero when no load is applied. Now, the cylinder 1 is fixed to a lifting table 11 at its lower part, and a male thread is carved on the outer diameter surface of the lifting table 11. Platform 13
It is inserted into the male thread engraved in the. Lifting platform 1
1 is equipped with a detent device 14, and therefore, as the rotating table 13 rotates, the lifting table 11 is displaced in the vertical direction. A worm wheel 13a is formed on the outer circumferential surface of the rotary table 13 and meshes with a wall 16 rotated by a motor 15. This motor 15 is rotationally driven by a control signal from the motor control circuit 9. Motor control circuit 9
is configured to supply a control signal to the motor 15 so that the amount of inclination of the lever 6 from the above-mentioned inclination amount detector 8 becomes zero. Note that the rotation of the motor 15 is detected by a rotation detector (not shown), and is introduced to the measuring unit 18 together with a temperature detection signal from the temperature measuring element 17 provided in the cylinder 1. The sample flow rate is calculated from the number, and a flow curve etc. are obtained from this change over time and recorded on the recorder 19.

Next, we will discuss the effect. When the sample in the cylinder 1 reaches the heated test temperature, the orifice 1b provided at the bottom of the cylinder 1 is released. At this time, since a load based on the weight 7 is applied to the plunger 2 by the lever 6 via the load shaft 4 and the press joint 3, the heated and melted sample starts to flow out from the orifice 1b. Due to this outflow, the plunger 2 is displaced downward and the lever 6 is tilted, but the amount of this tilt is detected by the tilt amount detector 8, and the motor control circuit 9 rotates the motor 15 so that the value becomes 0. The cylinder 1 is driven upward via the rotating table 13 on which the wall 16 and the wall wheel 13a are formed, and the lifting table 11. In this way, the cylinder 1 is driven according to the outflow speed of the sample, and the lever 6 applies a load to the plunger 2 by following the outflow of the sample without being substantially tilted.

As explained above, according to the present invention, a load based on the weight of the weight can be constantly applied to the lever in a horizontal state without substantially tilting it even when the sample flows out. In this way, the effects of inertial force caused by lever tilt acceleration, load errors caused by lever tilt, etc. can be removed.
Not only can the accuracy of the applied load be improved, but also the relative displacement between the plunger and the cylinder can be increased, so the measurement range (time) can be expanded. Furthermore, according to the embodiment of the present invention, by fixing the lever and attaching a load cell to the press joint, for example, and rotating the motor at a constant speed and detecting the load at that time, flow rate measurement at constant strain can be performed. It can also be used for testing.

[Brief explanation of the drawing]

The drawing is a configuration diagram of an embodiment of the present invention. 1... Cylinder, 1a... Heater, 1b... Orifice, 2... Plunger, 6... Lever, 6
a... Fulcrum, 7... Weight, 8... Tilt amount detector,
9...Motor control circuit, 11...Lifting platform, 13...
... Turntable, 13a... Wall wheel, 15...
...Motor, 16...Wall, 18...Measuring unit.

Claims (1)

[Scope of utility model registration request] A cylinder equipped with a heating function and an orifice at the lower end, a plunger that can slide vertically within the cylinder, and a plunger that can rotate freely with one end as a fulcrum and that uses the weight of a weight suspended at the other end to transfer the load to the plunger. In the device, the device is equipped with a lever that acts on the heated molten sample in the cylinder, presses the heated molten sample in the cylinder under a constant load with the plunger, pushes it out from the orifice, and measures the flow rate over time,
It comprises means for detecting the amount of inclination of the lever, and means for introducing the output of the detection means to drive the cylinder in the vertical direction so that the amount of inclination of the lever becomes 0, so as not to substantially incline the lever. A flow tester characterized in that the plunger is configured to apply a load based on the weight of the weight to the plunger.