JPH0547400Y2 - - Google Patents

Description

[Detailed description of the invention] A. Industrial application field This invention is an electrical technology used in an extrusion type capillary rheometer that measures the flow characteristics, molecular weight distribution, viscosity effects, etc. of samples such as plastics, ceramics, rubber, and cosmetics. Regarding furnaces.

B. Prior Art Figure 3 schematically shows the configuration of the heating furnace part of a conventional extrusion type capillary rheometer installed in a material testing machine in which a specimen is loaded by separating a pair of opposing members (not shown). FIG. The sample 1 is filled into the barrel 2 and heated by a plurality of band heaters 3 arranged around the barrel 2, thereby melting the sample 1 inside the barrel 2. Then, by applying a constant pressure with a plunger 4 connected to a movable member (not shown), the molten sample 1 is pushed out from an orifice 5 provided at the lower end of the barrel 2. Plunger 4 at this time
The fluidity of the sample is now measured by calculating the viscosity of the sample from the moving speed of the sample.

C. Problems to be solved by the invention By the way, in the above-mentioned capillary rheometer, the electric furnace for melting the sample, which is composed of the barrel 2, band heater 3, orifice 5, etc., is generally mounted on a mount on the table TB of the test body. Although the barrel 2 is supported in a suspended state by the PD, in particular, the upper end of the barrel 2, which directly receives the pressure of the plunger 4 for sample extrusion, is supported in a directly connected state to the pedestal PD.
The heat in the upper part of the barrel heated by the band heater 3 is dissipated to the outside of the furnace through the pedestal PD. As a result, a temperature difference occurs between the top and bottom of the barrel 2, and a temperature difference also occurs between the top and bottom of the molten sample, making it impossible to melt with a uniform temperature distribution, which in turn makes it impossible to accurately measure the properties of the sample. Another problem was that heat from the barrel was taken away by the mount PD, which resulted in a longer temperature rise time before the test started.

The technical problem of the present invention is to make the temperature distribution of the sample filled in the barrel uniform over the entire area.

D. Means for Solving the Problems The present invention will be explained in conjunction with FIG. 1 showing an embodiment.
a plurality of independently controlled band heaters 22, 23, 24 arranged along the longitudinal direction of the barrel 21 and heating the barrel 21 to melt the sample in the barrel;
and the upper part of the band heater 22, and the barrel 2
1 and an independently controlled ring heater 25 that heats the introduction side of the plunger 1 and compensates for the thermal energy dissipated from the barrel 21.

E Effect By heating the barrel 21 with each of the band heaters 22, 23, and 24, the sample filled in the barrel 21 is melted. The ring heater 25 operates to heat the plunger introduction side of the barrel 21, thereby compensating for the thermal energy dissipated from the upper end of the barrel to the outside of the furnace. Therefore, the temperature distribution of the molten sample within the barrel can be made uniform over the entire area.

Note that in the above sections D and E explaining the configuration of the present invention, figures of embodiments are used to make the present invention easier to understand, but the present invention is not limited to the embodiments.

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

FIG. 1 is a cross-sectional view of a portion of an electric furnace for a capillary rheometer according to the present invention, and FIG. 2 is an overall view of the capillary rheometer.

First, in Fig. 2, 10 is a table of the main body of the testing machine, and 11 is a pair of columns erected on the table 10.A crosshead 12 is horizontally suspended between the left and right columns 11, and this crosshead 12 is connected to the left and right columns. It can be moved up and down by being screwed together with the pillar. A load cell 13 for detecting the load pressure on the sample is installed on the crosshead 12 using a support stand 14, and a load rod 15 passing through the crosshead 12 is placed on the lower surface of the load cell 13 and can be moved up and down by a guide unit 16. is attached to. The upper end of a plunger 18 for pushing out a sample is connected to the lower end of the load rod 15 via a connector 17.

19 is located inside the support 11 and the table 10
A portal-shaped furnace support pedestal is installed above, and the upper end of the electric furnace 20 is suspended from this furnace support pedestal 19 .

As shown in FIG. 1, the electric furnace 20 includes a pipe-shaped barrel 21 that is roughly divided and arranged in the reactor core, an independently controlled upper band heater 22 that melts the sample filled in the barrel 21, and an intermediate band heater 23. and a lower band heater 24 , an independently controlled internal ring heater 25 that compensates for the thermal energy released from the barrel 21 to the furnace support frame 19 , and a barrel 2
1 and the plunger 1 inserted therein.
Independently controlled external ring heater 26 that heats 8
It is composed of.

Upper band heater 22, middle band heater 23
The lower band heater 24 is disposed on the outer circumferential surface of a soaking tube 27 that is brought into close contact with the outer circumferential surface of the barrel 21 from the lower end of the barrel 21 toward the upper end, and the outer circumferential surface of each band heater 22, 23, and 24 is made of a heat insulating material. 2
8, 29, 30, and these band heaters 22, 23, 24 and the heat insulating material 2.
8, 29, and 30 are partitioned by air cooling parts 31a and 31b. In addition, the internal ring heater 25
is arranged in close contact with the outer peripheral surface of the barrel 21 located above the upper band heater 22, and includes a pair of ring-shaped heaters 25b, 25b buried concentrically in the cement material 25a, and the cement material 25.
It is composed of a holder 25c that covers the outer periphery of a.

The entire outer periphery of the heat insulating materials 28, 29, 30 and the internal ring heater 25 combined in this way is covered by a cylindrical heat insulating material 32, and the outer peripheral surface of the heat insulating material 32 is further covered by an outer cylinder 33. At the same time, the upper and lower openings of the outer cylinder 33 are formed into a donut disk-shaped upper cover 34.
and is closed by a lower cover 35.

Further, the external ring heater 26 is connected to the furnace support frame 1
A pair of ring-shaped heaters 26b, 26b are installed on the outer periphery of the upper end of the barrel 21 that passes through the tube 9 upward, and are embedded concentrically in the cement material 26a.
and a holder 26c that holds the cement material 25a.
, a soaking tube 26d that is fitted onto the inner periphery of the holder 26c and screws into the threaded portion 21a formed on the outer periphery of the upper end of the barrel 21, a cement material 25a, and the holder 26c.
and a heat insulating material 26e covering the outer peripheral surface of the soaking tube 26d.
It is made up of.

The external ring heater 26 is fixed onto the furnace support frame 19 by means such as bolts, and the upper end threaded portion 21a of the barrel 21 is connected to the heat soaking tube 2.
6d, the entire electric furnace 20 including the barrel 21 is supported on the furnace support frame 19.

Note that 36 is a temperature sensor that detects the temperature of the external ring heater 26, and 37 to 40 are temperature sensors that detect the heating temperature of the barrel 21 corresponding to the upper band heater 22, intermediate band heater 23, lower band heater 24, and internal ring heater 25. These temperature sensors 36 to 40 are for controlling the heating temperature of each heater to a set value. Reference numeral 41 denotes an orifice that is replaceably fitted into the opening at the lower end of the barrel 21. This orifice 41 is held by a holding nut 42, and an orifice cap 43 is removably attached to the holding nut 42.

Next, the operation will be explained.

When measuring the viscous flow characteristics of samples such as plastics, ceramics, cosmetics, etc., fill the barrel 21 with a predetermined amount of the sample and press the plunger 18.
is inserted into the barrel 21 from its upper end opening, and the barrel 21 is heated by energizing each of the band heaters 22 to 24 and the ring heaters 25 and 26. After the sample in the barrel 21 is melted, the orifice cap 43 is removed and the crosshead 12 is lowered to lower the plunger 1.
8, a constant pressure is applied to the molten sample in the barrel 21. At this time, the pressure applied to the molten sample is kept constant by controlling the descending speed of the crosshead 12 so that the difference between the pressure detected by the load cell 13 and the set value becomes zero.

When a constant pressure is applied to the molten sample from above by the plunger 21, the molten sample is pushed out from the orifice 41 at the lower end of the barrel. The viscosity of the sample is determined from the moving speed of the plunger 21 at this time, and the fluidity of the sample is evaluated.

On the other hand, during the above-described test, the part of the barrel 21 located above the upper band heater 22 near the furnace support frame was replaced by an independent internal ring heater 2.
5, and the furnace support frame 1 is heated from this vicinity.
Since the thermal energy dissipated to the outside of the furnace through 9 is compensated for, the temperature in the vicinity of the mount will not drop, and the temperature distribution in the entire area of the barrel 21 can be uniform in order to melt the sample. The sample temperature distribution can also be controlled within ±0.5 to ±1.0°C over the entire area.

Furthermore, since the upper support end of the barrel 21 is heated by an independent external ring heater 26, it is possible to compensate for the heat dissipated into the atmosphere from the upper end of the barrel 21, and also to Since it is possible to preheat the plungers 18 that are sequentially inserted into the barrel 21, it is possible to prevent a temperature gradient from occurring in the upper part of the barrel due to the insertion of the plungers 18.
6, it is possible to shorten the time required to raise the temperature of the sample in the barrel to a desired temperature. Also,
By heating the barrel 21 with the upper, middle, and lower band heaters 22, 23, and 24, and the inner and outer ring heaters 25 and 26, the thermal conditions necessary to measure the fluidity properties of the sample are created. It also becomes possible to control accurately and easily.

Note that the number of band heaters in the present invention is not limited to the three shown in the above embodiment, but may be less or more than that. Alternatively, the electric furnace portion below the pedestal 19 may be installed on a fixed pedestal on the table 10 without being suspended from the pedestal 19, and in this case, an external ring heater is not required.

G Effect of the invention As explained above, according to the invention, the upper end of the barrel heated by multiple band heaters is heated by an independent ring heater, and the heating temperature can be controlled. Thermal energy dissipated from the barrel can be compensated for, and as a result, the temperature distribution of the molten sample within the barrel can be made uniform over the entire area, and the thermal conditions for the sample can also be accurately controlled.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of an electric furnace for a capillary rheometer according to the present invention. FIG. 2 is an overall configuration diagram of the capillary rheometer equipped with the electric furnace shown in FIG. 1. FIG. 3 is a schematic configuration diagram for explaining a conventional electric furnace for a capillary rheometer. 10... Table, 11... Support, 12... Crosshead, 13... Load cell, 15... Load rod, 18... Plunger, 19... Furnace support frame, 20... Electric furnace, 21... Barrel, 22 ……
Upper band heater, 23...middle band heater,
24... Lower band heater, 25... Internal ring heater, 26... External ring heater, 27, 26
d... Soaking tube, 36-40... Temperature sensor, 41
...Orifice chair.

Claims (1)

[Scope of utility model registration request] In an electric furnace used in a capillary rheometer, the properties of the sample are measured by filling a sample into a barrel placed in the core of a heating furnace, heating and melting the sample, and extruding it from the orifice of the barrel with a plunger at a constant pressure. , a plurality of independently controlled band heaters disposed around the outer periphery of the barrel along its longitudinal direction for heating the barrel and melting the sample in the barrel; An electric furnace for a capillary rheometer, characterized in that it is equipped with an independently controlled ring heater that heats the introduction side of the plunger and compensates for the thermal energy dissipated from the barrel.