JP5420487B2 - Thermocouple temperature detector for high viscosity materials - Google Patents

Description

  The present invention is suitable for rapid detection of a temperature change of a material kneaded in a kneading tank in a kneading machine for high-viscosity kneading materials such as rubber and plastic, or in an extruder cylinder for the kneading materials. The present invention relates to a thermocouple temperature detector for high-viscosity materials that measures and outputs a thermoelectromotive force generated by the Seebeck effect.

Conventionally, a thermocouple temperature detector that measures a temperature by storing a thermocouple element in a protective tube is used to measure the exothermic temperature of a kneaded material kneaded in a kneading machine for high viscosity kneading materials such as rubber and plastic. The exothermic temperature is measured by the thermocouple temperature detector. The thermocouple element detection end of the thermocouple temperature detector protrudes slightly from the bottom or side wall of the kneading tank into the tank, and the temperature of the kneaded material in contact with it is measured. I try to detect it.
The temperature detector measures the temperature change of the kneaded product during the kneading operation, transmits it to the automatic kneading control mechanism, displays the measured temperature, and performs necessary operation control at the set kneading end temperature, etc. It is required to have an important function as a sensor of the state in the kneading tank that cannot be seen.

For example, in a high-viscosity material kneading machine in which two kneading rotors are arranged in parallel and rotated so as to mesh with each other, a compound or the like having a high-viscosity organic polymer material lump or granular material is kneaded. However, these kneaded materials are subjected to a powerful kneading load provided by the twin-screw kneading rotor rotating in mesh with each other and a pressure load of the pressure lid that suppresses the lift of the compounding agent from above the kneading tank. The counter element is attached to the body of the kneading machine as a thermocouple temperature detector housed in a protective tube having a strong material and strength having wear resistance and impact resistance.
Therefore, the temperature of the kneaded material that changes in accordance with the progress of kneading is conducted to the thermocouple element through the protective tube, that is, the thermocouple element does not directly sense the temperature of the kneaded material, but the temperature of the protective tube itself. Therefore, it is not sensitive to the temperature change of the kneaded product.

  In the actual operation of such a thermocouple temperature detector in a commercial kneader, the temperature measurement value is 10 ° C. to 25 ° C. (difference depending on the hardness of the kneaded material) from the measured temperature of the kneaded material discharged from the kneader. The temperature sensor is usually low, because the temperature-sensitive part at the tip of the temperature detector is subjected to severe wear, a strong kneading stress applied from the kneading rotor that meshes and rotates in the kneading tank, and kneading from above the kneading tank. The thermocouple element is housed in a sturdy protective tube so that it will not be damaged by the pressure load of the pressure lid that suppresses the lifting of objects, so the temperature of the kneaded rubber is not directly transmitted to the thermocouple element. The current situation is giving up.

  As a thermocouple accommodated in such a protective tube, a grounded type and a non-grounded type are practically used. The grounding type is a method adopted in the present invention. The tip of the thermocouple element is welded to the tip of the protective tube, the temperature of the object to be measured is sensed on the outer surface of the protective tube, and the generated thermoelectromotive force is transmitted via the conductor. However, there is no satisfactory one in terms of minimizing the heat capacity of the tip of the protective tube that senses temperature changes while maintaining the heat insulation and strength of the tip of the protective tube. On the other hand, the ungrounded type senses the temperature of the protective tube by bringing the thermocouple element into contact with the inner wall of the protective tube, but sometimes the temperature of the thermocouple element accommodated inside the protective tube in an ungrounded state is detected. In some cases, the sensing end measures the temperature of the air in the protective tube, and the measured value from the thermocouple element housed in the protective tube does not accurately follow the actual temperature of the object being measured. Not captured.

  Further, when the rubber compound is kneaded in a closed kneader, in order to promote the dispersion of the kneaded material in the kneading tank, the filling rate of the compounding material is set to 60 to 80% of the volume of the kneading tank, and the kneaded material flows. A space is provided. Therefore, the kneaded product is not always in close contact with the detection end of the thermocouple element, and the kneaded product comes into contact with the temperature sensing portion of the temperature detection end of the thermocouple element as the two-shaft rotor engages. And move violently in the flow space in the kneading tank. That is, the kneaded material repeats instantaneous contact with the temperature detection end, and the accurate temperature of the kneaded material during kneading cannot be measured unless the detection end has a sensitive temperature sensing follow-up.

  As described above, the closed-type kneaders that have been used at the present high technical level cannot display the exact temperature on the instrument as a numerical value, and normally a temperature lower than the actual temperature is displayed. In fact, the related engineers are working on the measured temperature and the kneaded material because of the attachment of protective tubes that prioritize the provision of wear resistance and impact resistance to the thermocouple element. The temperature difference is accepted, and the precise end point of kneading according to temperature is grasped, and precise temperature-controlled automatic kneading that ends kneading by setting an upper limit temperature is sacrificed. This is a factor of variation in batch quality characteristics of the kneaded product.

  The performance required for a high-performance temperature detector is a function that requires a short time to measure the temperature of the object to be measured and can quickly follow changes in the temperature of the object to be measured. The temperature sensed at the tip of the thermocouple detector It is required to display the temperature without time lag even if there is a protective tube. In other words, it is possible to realize a structure that accurately and quickly senses the temperature change of the temperature-measuring object, generates a thermoelectromotive force, and reliably transmits the thermoelectromotive force to the temperature indicator.

  The technical problem of the present invention is that the temperature of the object to be measured cannot be accurately measured by accommodating the thermocouple element in the protective tube, but the protective tube cannot be excluded. It can be stored in a protective tube with a structure that is close to direct contact, and the strength of the protective tube is maintained by the heat transfer from the body of the temperature measuring material processor equipped with the temperature detector to the thermocouple element through the protective tube. An object of the present invention is to provide a thermocouple temperature detector for a high-viscosity material that can be effectively suppressed.

In order to solve the above problems, according to the present invention, a thermocouple element configured by welding one end of two kinds of metal wires having different compositions that generate thermoelectromotive force by the Seebeck effect is accommodated in a protective tube, Attach the thermocouple element to the kneading tank so that the welded end of the thermocouple element is in direct contact with the high-viscosity material flowing in the tank by kneading in the kneading tank for high-viscosity material. In the thermocouple temperature detector to be detected, the welded end of the thermocouple element was opened at the tip of the closed portion of the protective tube closed as a hemispherical bulging shape with the tip protruding into the kneading tank . A temperature sensitive part is formed by inserting the welded end portion into the protective tube from the outside by inserting it into the pores, insulating the two types of metal wires of the thermocouple element, and the inside of the protective tube Direction Conduct the lead to the terminal block of the detector body that is fixed on the end side, cover the outer periphery excluding the temperature sensing part at the tip of the protective tube with a heat insulating insulating film cylinder, and through the gap outside the heat insulating film cylinder By covering the seal tube, the thermocouple element to be mounted on the body of the kneading machine for high viscosity material is accommodated in the double tube, and heat transfer between the thermocouple element and the body is performed by the insulating film cylinder and the gap. There is provided a thermocouple temperature detector for high viscosity materials characterized in that it is inhibited.

In a preferred embodiment of the thermocouple temperature detector for a high viscosity material according to the present invention, a cylindrical shape having a slightly larger diameter than the seal tube is formed at the tip of the seal tube attached to the body of the kneader for the high viscosity material. A tip member is fitted, an exposure hole is formed at the tip of the tip member to expose the tip temperature sensing portion of the protection tube to the outside, and the inner wall of the exposure hole is connected to the protection tube so that the temperature sensing portion protrudes. The sealing tube can be externally fitted to a protective tube in close contact with the insulating film cylinder on the outer surface and the tip member is fitted on the outside of the insulating film cylinder. A gap formed between the detector mounting hole and the seal tube when mounted in the detector mounting hole in the body of the kneading machine for high viscosity material , and between the seal tube and the protective tube A vent hole is established to communicate with the intervening gap, and the vent hole communicates with the vent hole. The serial two gaps, the sealing tube can be configured as being open to the atmosphere through a fixed metal fitting attached to the body.

  According to the thermocouple temperature detector for high viscosity material of the present invention described in detail above, the thermocouple element can be stored in the protective tube with a structure close to directly touching the object to be measured, and the temperature detector is mounted. A thermocouple temperature detector for high viscosity materials that can effectively suppress the heat transfer from the temperature measuring material processing machine body to the thermocouple element through the protective tube while maintaining the strength of the protective tube can do.

It is an external view which shows an example of implementation of the thermocouple temperature detector for high viscosity materials which concerns on this invention. It is sectional drawing which shows the internal structure of the thermocouple temperature detector of FIG. It is a principal part expanded sectional view of FIG. It is sectional drawing which shows the state with which the said thermocouple temperature detector was mounted | worn with the kneading tank of the closed kneading machine. It is a graph which shows the temperature measurement record at the time of rubber kneading | mixing by the closed-type kneader equipped with the prototype thermocouple temperature detector. It is a graph which shows the temperature measurement record at the time of kneading | mixing from which the case of FIG. 5 differs.

  1 to 4 show an embodiment of a thermocouple temperature detector for a high viscosity material according to the present invention. The thermocouple element 2 for temperature detection in the thermocouple temperature detector 1 includes two types of metal wires 2a and 2b (see FIG. 3) having different compositions that generate thermoelectromotive force due to the Seebeck effect, such as an alumel wire and a chromel. The wire is formed by welding one end of each of the metal wires 2a and 2b with a thin wire diameter having good temperature change followability, and is formed by the welded end portion 2c of the metal wires 2a and 2b. An object to be measured, which is made of a high-viscosity material kneaded by a temperature measuring material processing machine such as a kneading tank 20 (see FIG. 4) in a rubber or plastic kneading machine or an extruder cylinder by the temperature sensing unit 3. Temperature detection is performed.

  More specifically, as shown in detail in FIGS. 2 and 3, the thermocouple element 2 is housed in a protective tube 5 and flows through the welded end 2c. The thermocouple temperature detector 1 for detecting the temperature of the thermocouple element 2 is attached to the protective tube 5 by first attaching the welded end 2c of the thermocouple element 2 with a hemispherical tip. The protective tube 5 closed as a bulging shape is inserted into the pore 5a opened at the protruding end of the closed portion from the inner side of the protective tube 5, and the end 2c is inserted into the protective tube 5 from the outside. It is welded in the pore 5a by prime welding and sealed and fixed to the protective tube 5 in the grounded state, and the tip of the protective tube 5 is reinforced by the built-up portion 5c accompanying the welding, whereby the thermocouple element 2 The temperature sensitive part 3 is formed. This configuration is effective for minimizing the heat capacity of the temperature sensing portion 3 at the tip of the protective tube that senses the temperature change of the kneaded material while maintaining the strength of the protective tube 5.

  The two types of metal wires 2a and 2b of the thermocouple element 2 inserted into the protective tube 5 are respectively covered with an insulating coating 4, and the inner wall of the protective tube 5 and the metal wires 2a and 2b are electrically connected to each other. So that the protective tube 5 is led to the other open end side, and the protective tube 5 is led to the terminal block 8 provided in the detector body 7 fixed by the fixing bracket 6. It is connected there. The two types of metal wires 2a and 2b of the thermocouple element 2 connected to the terminal block 8 are connected to various instruments by being led out from the inside of the detector body 7 through conductive wires, The temperature is displayed as a temperature value based on the thermoelectromotive force or used as a control signal.

  The protective tube 5 is covered with an insulating film cylinder 10 having a heat insulating property and an electric insulating property, except for the temperature sensing portion 3 at the tip, and is sealed with a gap 11 outside the insulating film cylinder 10. By covering the tube 12, the thermocouple element 2 is mechanically protected by the double tube of the protective tube 5 and the seal tube 12, and at the same time, the metal wires 2a and 2b are thermally insulated to detect the detector body 7. It can be derived to the side. That is, the seal tube 12 to be mounted on the body of the temperature measuring material processing machine such as the kneading tank 20 is fitted with a tip member 12a having a slightly larger diameter than the seal tube 12 at the tip, An exposure hole 12b for exposing the tip temperature sensing portion 3 of the protection tube 5 to the outside is opened at the tip of the tip member 12a, and the inner wall of the exposure hole 12b is formed on the outer surface of the protection tube 5 so that the temperature sensing portion 3 protrudes. The seal tube 12 fitted to the protective tube 5 in close contact with the insulating film cylinder 10 and fitted with the tip member 12 a is put on the outside of the insulating film cylinder 10 through the gap 11. Accordingly, the insulating film cylinder 10 and the outer space 11 form a heat insulating layer interposed between the protective tube 5 and the seal tube 12 on the outer periphery of the protective tube.

  The fixed end 12c on the proximal end side of the seal tube 12 is fitted into a seal tube fixing hole 6a provided in the fixing bracket 6 for attaching the thermocouple temperature detector 1 to the body of the temperature measuring material processing machine such as the kneading tank 20 or the like. The base end of the protective tube 5 inserted through the seal tube 12 is connected to the detector main body of the fixing bracket 6 from the center of the inner bottom of the seal tube fixing hole 6a. 7 is inserted into the protective tube fixing hole 6c penetrating the mounting portion 6b, and the distal end 5b of the inserted protective tube 5 is welded to the distal end of the mounting portion 6b of the fixing bracket 6 on the side penetrating the protective tube fixing hole 6c. It is fixed by doing. The fixing bracket 6 is fixed to the detector main body 7 by fitting its mounting portion 6 b into a mounting hole 7 a provided in the detector main body 7. Accordingly, the metal wires 2 a and 2 b constituting the thermocouple element 2 pass through the fixing fitting 6 through the protective tube 5 and are led to the terminal block 8.

  As shown in FIG. 4, the thermocouple temperature detector 1 having the above-described configuration includes the above two kneading units in a kneading tank 20 made of rubber or the like that rotates two kneading rotors 21 arranged in parallel to engage with each other. It attaches to the partition wall 20a between the rotors 21, etc., and uses for temperature detection of high viscosity materials, such as rubber | gum to knead | mix. In order to attach the thermocouple temperature detector 1 to the kneading tank 20 or the like, a detector mounting hole 22 is opened at an attachment site of the temperature detector 1 in the kneading tank 20 or the like. In order to prevent leakage of the kneaded material, the opening diameter of the seal tube 12 protruding into the kneading tank 20 is configured so that the tip member 12a can be fitted with high precision so that the tip member 12a can be closely fitted. The

  Further, since the tip member 12 a has a larger diameter than the seal tube 12, the detector mounting hole 22 into which the tip member 12 a is inserted is fitted into the mounting hole 22 at the outer portion of the kneading tank 20. In the inserted portion, the detector mounting hole 22 inevitably has a larger diameter than the seal tube 12, and a gap 24 is formed between the mounting hole 22 and the seal tube 12. The insertion guide hole 22a of the seal tube 12 that is concentric with the hole 22 and opens to the outside of the kneading tank 20 is cut to a diameter larger than that of the mounting hole 22. As a result, insertion on the inlet side of the detector mounting hole 22 is performed. When the screw portion 6d of the fixing metal fitting 6 is screwed into the guide hole 22a and fixed with the lock nut 6e, the above-mentioned for heat insulation is provided between the seal tube 12 and the inner surface of the detector mounting hole 22 and the insertion guide hole 22a. A gap 24 is formed. The fact that the opening diameter of the detector mounting hole 22 provided at the attachment site of the temperature detector 1 in the kneading tank 20 and the like can fit the tip member 12a of the seal tube 12 with high accuracy also prevents leakage of the kneaded material. Although necessary, the sealing tube 12 is firmly fixed to the kneading tank 20 and, as a result, the protective tube 5 formed in a thin wall with a small heat capacity in order to enhance the heat sensitivity is used as the body of the temperature measuring material processing machine. It is also effective for stably fixing in a thermally insulated state.

  In fixing the seal tube 12 to the kneading tank 20, one or more vent holes 12d are opened in the seal tube 12 located inside the detector mounting hole 22 and the insertion guide hole 22a in the kneading tank 20, The gap 11 between the protective pipe 5 and the seal pipe 12 constituting the double pipe is communicated with a gap 24 formed between the detector mounting hole 22 and the insertion guide hole 22a outside the seal pipe 12. Yes. The gap 24 is communicated with the atmosphere through one or a plurality of ventilation channels 6f formed as holes or grooves in the fixture 6 for attaching the seal tube 12 to the airframe.

  Thus, the protective tube 5 and the seal tube 12 constitute a double tube, and the insulating film cylinder 10 around the protective tube 5 inhibits heat transfer between the protective tube 5 and the protective tube 5. The gap 11 between the seal pipe 12 and the detector mounting hole 22 of the kneading tank 20 and the gap 24 between the insertion guide hole 22a and the seal pipe 12 communicate with the atmosphere, so that there is a relatively large space outside the machine. An air film having a temperature with little fluctuation is formed, heat transfer from the kneading tank 20 to the temperature sensing part 3 of the protective tube 5 is suppressed, and the temperature of the temperature sensing part 3 can be stabilized.

  That is, when the machine temperature of the kneading tank 20 rises, the air staying in the gap 24 around the seal tube 12 is heated by the heat transmitted from the machine body of the kneading tank 20, and is thermally expanded to pass through the ventilation channel 6 f of the fixture 6. Further, the air in the gap 11 between the protective tube 5 and the seal tube 12 is also released to the atmosphere and flows out between the outer wall of the seal tube 12 and the insertion guide hole 22a through the vent hole 12d. The air flows out of the machine body through the air flow path 6f, and the air holes 12d and the air flow paths 6f are appropriately arranged so that external air flows from a part of them to the seal pipe 12 and the like. Heat storage can be suppressed.

  It is estimated that the amount of air flowing in and out of the ventilation channel 6f is extremely small, but it eliminates disturbance factors to the temperature sensing in the temperature sensing section 3, such as heating from the kneading tank and heat removal from the kneading tank. Thus, the temperature sensing unit 3 can more accurately sense the temperature change of the object to be measured, and transmit the thermoelectromotive force to the thermometer. Note that the air film of the air gaps 11 and 24 is effective as an adiabatic protection for the protective tube 5 from the influence of the external temperature. The temperature change gradient is remarkable in the experimental examples shown in FIGS. It is verified by being displayed.

  In the thermocouple temperature detector having the above-described configuration, the metal wires 2a and 2b constituting the thermocouple element 2 are grounded and sealed at the tip of the protective tube 5, so that the temperature sensing speed of the kneaded material is remarkably increased. This has been confirmed, and this has been confirmed by experimental examples described below with reference to FIGS.

The experimental example described with reference to FIG. 5 and FIG. 6 is an example in which the thermocouple temperature detector 1 for high-viscosity materials of FIGS. 1 to 3 described as the above embodiment is used in a kneading tank 20 of a kneader for kneading a rubber compound. FIG. 5 is an example of temperature measurement when the rubber compound is kneaded as shown in FIG.
5 and 6, the kneading drive power of the kneader when kneading two kinds of rubbers with different blending, the rotational speed of the kneading rotor 21, and the suppression of the lift of the kneaded material from above the kneading tank 20 are added. The graph shows the kneading record in which the time variation of the pressure load due to the weight pressure of the pressure lid and the temperature of the kneaded material measured by the thermocouple temperature detector 1 is taken into a computer controller and graphed.

  First, the kneading record of FIG. 5 is a case where the kneading end temperature is set to 80 ° C. by automatic kneading control by the computer control device, and a vulcanizing agent is added to a 50 kg rubber compound and kneaded. The kneading time reached 80 ° C. in about 120 seconds, and the kneading rotor 21 was automatically stopped at the end of kneading, so the kneaded material was discharged. As a result of immediately measuring the temperature of the discharged kneaded rubber with a platinum resistance thermometer, the worker showed 78.8 ° C. On the other hand, the temperature display based on the thermocouple temperature detector 1 of the automatic control system recorded 78.6 ° C. The actual temperature difference of the kneaded rubber discharged with respect to the temperature display value at the end of kneading showed a value higher by + 0.2 ° C., which is presumed to be a partial temperature variation or a measurement error range.

  The test record shown in FIG. 6 is a record of the kneading state for about 8 minutes by full compound kneading. The set value of the kneading end point was automatically set to 150 ° C., and the measured temperature of the discharged rubber by the platinum resistance thermometer was 149.4 ° C., which was 0.6 ° C. lower than the displayed temperature. It cannot be low, and the measured value of the kneading temperature is ± 0 ° C. When the transition of the test kneading process is recorded in analog form, the kneaded product is at the same timing as the power consumption (reduction) transition curve A (the state in which hard rubber is plasticized) indicated by the kneading drive power consumption curve. The temperature rise curve B (increased frictional heat storage by kneading) is recorded, and the temperature drop curve C (air temperature in the kneading tank) in the kneader after discharging the kneaded material at the end of kneading is also recorded. As the curve drops at a steep angle at the same time as the discharge, the temperature-sensitive followability remains a good record.

  The temperature rise curve B and the temperature drop curve C record the temperature change that rises and falls finely, but this up and down change finely senses the temperature change of the behavior of the kneaded material coming in contact with or leaving the temperature sensitive part 3. It shows that you are doing. Such precise and accurate temperature measurement has not been possible with a thermocouple temperature sensor used in a conventional kneader. In conventional kneading, kneaded rubber having a temperature higher than the control set temperature (10 to 20 ° C.) is discharged by excessive kneading, and the amount of expensive heat-resistant anti-aging agent is added to maintain the rubber quality from this overheating. However, the above-mentioned accurate temperature measurement by the thermocouple temperature detector of the present invention realizes energy-saving kneading with grasping the end point of accurate kneading by temperature. The practicality of temperature control kneading, which was difficult to be practical, can be increased, and the variation in kneading quality characteristics for each batch when temperature controlled kneading is performed can be reduced.

  This result improves the effectiveness of the original quality control index for the recording of the power consumption curve and the temperature curve displayed on the analog recorder that has been used as a quality control index of the kneaded material. According to the present invention, it is possible to provide a thermocouple temperature detector equipped in a temperature measuring material processing machine such as a kneader that can compress the variation in quality characteristics caused by high-temperature kneading of rubber to the maximum.

DESCRIPTION OF SYMBOLS 1 Thermocouple temperature detector 2 Thermocouple element 2a, 2b Metal wire 2c End part 3 Temperature sensing part 5 Protective tube 5a Pore 6 Fixing metal fitting 6f Ventilation flow path 7 Detector main body 8 Terminal block 10 Insulating film cylinder 11 Cavity 12 Seal Tube 12a Tip member 12b Exposed hole 12d Vent hole 22 Detector mounting hole 24 Air gap

Claims (3)

A thermocouple element constituted by welding one end of two kinds of metal wires having different compositions that generate thermoelectromotive force by the Seebeck effect is accommodated in a protective tube, and the welded end of the thermocouple element is made of a high-viscosity material. In a thermocouple temperature detector that is attached to the kneading tank so as to be in direct contact with the high viscosity material flowing in the tank by kneading in the kneading tank, and detects the temperature of the high viscosity material ,
The welded end of the thermocouple element is inserted into a pore formed at the projecting end of the closed portion of the protective tube closed as a hemispherical bulging shape with the tip protruding into the kneading tank, and the welded Detecting that the other open end side is fixed inside the protective tube by forming the temperature sensitive part by welding the end to the protective tube from the outside, insulating the two types of metal wires of the thermocouple element, respectively Lead to the terminal block
The outer periphery of the protective tube excluding the temperature sensitive part is covered with a heat insulating insulating film cylinder, and the outer surface of the heat insulating film cylinder is covered with a seal pipe through a gap, so that the body of the kneading machine for high viscosity material can be used. The thermocouple element to be mounted is accommodated in a double pipe, and heat transfer between the thermocouple element and the airframe is suppressed by the insulating film cylinder and the gap,
A thermocouple temperature detector for high-viscosity materials. A tip member having a cylindrical shape slightly larger in diameter than the seal tube is fitted to the tip of the seal tube to be mounted on the body of the kneading machine for high viscosity material , and the tip temperature sensor of the protective tube is attached to the tip of the tip member. An exposure hole that exposes the portion to the outside is opened, and the inner wall of the exposure hole is brought into close contact with the insulating film cylinder on the outer surface of the protective tube so that the temperature-sensitive portion protrudes, and the tip member is attached to the protective tube. The fitted seal tube is put on the outside of the insulating film cylinder,
The thermocouple temperature detector for high-viscosity material according to claim 1. A gap formed between the detector mounting hole and the seal tube when the seal tube is mounted in the detector mounting hole in the body of the kneading machine for high viscosity material , and the seal tube and the protective tube A vent hole communicating with a gap interposed between the two and the two gaps communicating with each other in the vent hole is opened to the atmosphere through a fixing fitting for attaching the seal pipe to the fuselage.
The thermocouple temperature detector for high-viscosity materials according to claim 1 or 2.

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