阅读说明：本技术 一种在线测量橡胶挤出机计量段中橡胶粘度的装置和方法 (Device and method for measuring rubber viscosity in metering section of rubber extruder on line ) 是由 刘彦昌 林广义 于芳 马冲 梁振宁 胡亚菲 梁栋 于博全 于 2019-09-06 设计创作，主要内容包括：本发明公开了一种在线测量橡胶挤出机计量段中橡胶粘度的装置和方法,属于橡胶加工性能测量技术领域,该在线测量装置包括安装在所述橡胶挤出机的计量段机筒上的压力传感器,所述计量段机筒内转动安装有由驱动装置驱动的螺杆,所述压力传感器用于测量所述螺杆的螺槽中橡胶熔体的压力,所述压力传感器与示波器相连,所述示波器与数据处理系统相连,所述示波器用于显示所述压力传感器的齿状迹线,从而测量所述压力传感器锯齿状迹线斜率；所述数据处理系统可根据平均表观粘度表达式计算计量段中橡胶的平均表观粘度。该在线测量方法包括上述在线测量装置。本发明实现了橡胶挤出机计量段中橡胶熔体粘度的在线测量,有利于改善挤出加工过程的控制。(The invention discloses a device and a method for measuring the viscosity of rubber in a metering section of a rubber extruder on line, belonging to the technical field of rubber processing performance measurement, wherein the device comprises a pressure sensor arranged on a metering section cylinder of the rubber extruder, a screw driven by a driving device is rotatably arranged in the metering section cylinder, the pressure sensor is used for measuring the pressure of a rubber melt in a screw groove of the screw, the pressure sensor is connected with an oscilloscope, the oscilloscope is connected with a data processing system, and the oscilloscope is used for displaying a toothed trace of the pressure sensor so as to measure the slope of the sawtooth trace of the pressure sensor; the data processing system can calculate an average apparent viscosity of the rubber in the metering section from the average apparent viscosity expression. The online measuring method comprises the online measuring device. The invention realizes the on-line measurement of the viscosity of the rubber melt in the metering section of the rubber extruder and is beneficial to improving the control of the extrusion processing process.)

1. A device for measuring the rubber viscosity in the metering section of a rubber extruder on line is characterized by comprising a pressure sensor arranged on a metering section cylinder of the rubber extruder, wherein a screw driven by a driving device is rotatably arranged in the metering section cylinder, the pressure sensor is used for measuring the pressure of a rubber melt in a screw groove of the screw, the pressure sensor is connected with an oscilloscope, the oscilloscope is connected with a data processing system, and the oscilloscope is used for displaying a toothed trace of the pressure sensor so as to measure the slope of the toothed trace of the pressure sensor;

The data processing system can calculate an average apparent viscosity of the rubber in the metering section from the average apparent viscosity expression;

In the formula, H is the depth of a measuring section screw groove, S is the slope of a sawtooth trace of a pressure sensor, V is the rotating speed of a screw rotating line, V is pi DN, D is the diameter of the screw, N is the rotating speed of the screw, theta is a screw ridge helical angle, and phi is a flow function;

The flow function Φ is defined as: wherein Q is the net volumetric flow rate through the metering section; QD is the dragging volume flow rate of the metering section, QD is VzWH/2 is V WHcos θ/2 is α N, where Vz is the forward groove velocity at H, W is the groove width, H is the metering section groove depth, V is the screw rotation line speed, θ is the land helix angle, α is the dragging flow constant related to the screw geometric parameters, and N is the screw speed.

2. The apparatus of claim 1, wherein said Q is obtained by dividing the weight of the extrudate by the density of the rubber and the time, which are measured at regular time, or by multiplying the measured extrudate cross-sectional area by the measured extrusion line speed.

3. The apparatus of claim 1, wherein the drive means comprises a motor, and the screw speed N is measured by an encoder mounted on the motor.

4. The apparatus for on-line measurement of rubber viscosity in a metering section of a rubber extruder of claim 1, wherein the drag flow constant α should take into account the influence of flight width, leakage flow and flight pitch.

5. The apparatus of claim 1, wherein the metering section barrel is further provided with a temperature sensor for measuring the temperature of the rubber melt in the screw groove of the screw, and the temperature sensor is connected with the data processing system.

6. A method for the on-line measurement of the viscosity of rubber in a metering section of a rubber extruder, characterized in that the apparatus for the on-line measurement of the viscosity of rubber in a metering section of a rubber extruder as claimed in any of claims 1 to 5 is used.

Technical Field

The invention belongs to the technical field of rubber processability measurement, and particularly relates to a device and a method for measuring rubber viscosity in a metering section of a rubber extruder on line.

Background

Rubber melt is a typical non-newtonian fluid and viscosity is one of its important physical parameters. In rubber extrusion, calculating screw volumetric flow rate, viscous heat generation, and power consumption, among other things, requires data on the viscosity of the rubber melt in the metering section of the extruder. However, the viscosity of a non-Newtonian fluid has a dependence on shear rate and temperature and will vary with changes in shear rate and temperature.

To obtain rubber melt viscosity data under certain processing conditions, standard methods are often used for measurement, such as capillary rheometers, oscillating disc rheometers, and extrusion rheometers. While capillary rheometers and oscillating disc rheometers can measure viscosity at rubber extrusion processing shear rates and temperatures, they require extensive time-consuming experimentation and cannot be used for on-line measurements. Furthermore, during the transfer of the gum from the extrusion line to the capillary rheometer and the oscillating disc rheometer, additional relaxation effects will occur, adulterating the viscosity measurement data. While the extrusion rheometer avoids the additional relaxation effect described above, it measures the viscosity of the compound in the extruder head, where the flow, shear rate, and temperature of the compound are different from those in the metering section of the extruder, and using the viscosity data of the extrusion rheometer to calculate screw volumetric flow rate, viscous heat generation, and power consumption, etc., will produce large errors.

Therefore, in the technical field of rubber processability measurement, research and improvement needs still exist for an apparatus and a method for measuring the viscosity of rubber in a metering section of a rubber extruder on line, which is also a research focus and a focus in the technical field of rubber processability measurement at present and is the starting point of the completion of the invention.

Disclosure of Invention

in order to overcome the defect of measuring the rubber viscosity in the metering section of the rubber extruder by a standard method, the invention aims to solve the first technical problem that: provides a simple and reliable device for measuring the viscosity of rubber in a metering section of a rubber extruder on line.

As a concept, the second technical problem to be solved by the present invention is: provides a simple and reliable method for measuring the viscosity of rubber in a metering section of a rubber extruder on line.

In order to solve the first technical problem, the technical scheme of the invention is as follows: a device for measuring the rubber viscosity in the metering section of a rubber extruder on line comprises a pressure sensor arranged on a metering section cylinder of the rubber extruder, a screw driven by a driving device is rotatably arranged in the metering section cylinder, the pressure sensor is used for measuring the pressure of a rubber melt in a screw groove of the screw, the pressure sensor is connected with an oscilloscope, the oscilloscope is connected with a data processing system, and the oscilloscope is used for displaying a toothed trace of the pressure sensor so as to measure the slope of the toothed trace of the pressure sensor;

the data processing system can calculate an average apparent viscosity of the rubber in the metering section from the average apparent viscosity expression;

In the formula, H is the depth of a measuring section screw groove, S is the slope of a sawtooth trace of a pressure sensor, V is the rotating speed of a screw rotating line, V is pi DN, D is the diameter of the screw, N is the rotating speed of the screw, theta is a screw ridge helical angle, and phi is a flow function;

the flow function Φ is defined as: wherein Q is the net volumetric flow rate through the metering section; QD is the dragging volume flow rate of the metering section, QD is VzWH/2 is V WHcos θ/2 is α N, where Vz is the forward groove velocity at H, W is the groove width, H is the metering section groove depth, V is the screw rotation line speed, θ is the land helix angle, α is the dragging flow constant related to the screw geometric parameters, and N is the screw speed.

as an improvement, the Q can be obtained by dividing the weight of the extrudate by the density of the rubber and the time, which are measured in timed amounts, or by multiplying the measured extrudate cross-sectional area by the measured extrusion line speed.

As a refinement, the drive device comprises an electric motor, and the rotational speed N of the screw can be detected by means of an encoder mounted on the electric motor.

As an improvement, the drag flow constant α should take into account the effects of flight width, leakage flow, and flight ridges.

As an improvement, a temperature sensor for measuring the temperature of the rubber melt in the screw groove of the screw is further arranged on the cylinder of the metering section, and the temperature sensor is connected with the data processing system.

In order to solve the second technical problem, the technical solution of the present invention is: a method for measuring the viscosity of rubber in a metering section of a rubber extruder on line adopts the device for measuring the viscosity of the rubber in the metering section of the rubber extruder on line.

after the technical scheme is adopted, compared with the prior art, the invention has the beneficial effects that:

1) The shear rate and the temperature-dependent viscosity of the rubber melt in the metering section of the rubber extruder can be measured on line;

2) a direct and reliable method for determining the local state of the extrusion process is provided, which is beneficial to improving the control of the extrusion processing process.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

The structures, ratios, sizes, and the like shown in the present specification are only used for matching with the contents disclosed in the specification, so that those skilled in the art can understand and read the present invention, and do not limit the conditions for implementing the present invention, so that the present invention has no technical significance, and any structural modifications, changes in the ratio relationship, or adjustments of the sizes, without affecting the functions and purposes of the present invention, should still fall within the scope covered by the contents disclosed in the present invention.

FIG. 1 is a schematic structural diagram of an apparatus for on-line measurement of rubber viscosity in a metering section of a rubber extruder provided in an embodiment of the present invention;

FIG. 2 is a schematic view of the mounting of a pressure sensor on the barrel of the metering section;

FIG. 3 is a schematic of a periodic serrated pressure cycle;

In the figure: 1-machine head, 2-metering section machine barrel, 3-temperature sensor, 4-pressure sensor, 5-oscilloscope, 6-data processing system and 7-screw.

Detailed Description

The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.