阅读说明：本技术 一种测量闪蒸纺丝过程中丝束与气流冲击力的装置 (Device for measuring impact force between tows and airflow in flash spinning process ) 是由 罗章生 余伦斌 于 2021-07-21 设计创作，主要内容包括：本发明涉及一种测量闪蒸纺丝过程中丝束与气流冲击力的装置,将现有技术中的偏转装置由偏转板改进为绝缘底板和压力感受器的组合。通过电刷、导线与电阻计测量出压阻材料制成的压力感受器在受到丝束与气流的冲击力后产生的电阻变化,得到所述冲击力大小,适应性改变绝缘底板的抗压距离,从而稳定该冲击力,提高丝束网被分散的均匀程度,最终提高闪蒸纺丝无纺布的单位质量均匀度。(The invention relates to a device for measuring impact force of filament bundles and air flow in a flash spinning process, which improves a deflection device in the prior art into a combination of an insulating bottom plate and a pressure sensor from a deflection plate. The pressure sensor made of piezoresistive material is measured by the electric brush, the wire and the resistance meter to generate resistance change after receiving the impact force of the filament bundle and the air flow, the impact force is obtained, the compression resistant distance of the insulating bottom plate is adaptively changed, the impact force is stabilized, the dispersed uniformity of the filament bundle net is improved, and the unit mass uniformity of the flash spinning non-woven fabric is finally improved.)

1. A device for measuring impact force between tows and air flow in a flash spinning process is characterized by comprising the following components: the device comprises an insulating bottom plate, a pressure sensor, an electric brush, a constant force spring, a resistance meter and a lead;

the insulation base plate is of a cylindrical structure, one bottom surface of the insulation base plate faces the moving direction of the filament bundles, the center of the other bottom surface is connected with a rotating shaft of a flash spinning device, an annular cylindrical groove is formed in the filament bundle facing surface of the insulation base plate and used for receiving the pressure sensor, the groove is wound on a cylindrical protrusion, the pressure sensor is made of piezoresistive material, the pressure sensor is embedded in the groove and rotates along with the insulation base plate, the surface of the pressure sensor is divided into an inner annular area and an outer annular area, the inner annular area is used for receiving impact force to generate change of resistance value, the outer annular area is in contact with two electric brushes, the electric brushes are pressed on the outer annular area by the constant force spring, and the constant force spring ensures that the pressure of the electric brushes on the surface of the pressure sensor is uniform, the electric brush does not rotate along with the deflection device and the pressure sensor, the resistance meter is electrically connected with the electric brush through the lead, and the resistance meter is matched with the electric brush to measure the resistance value of the pressure sensor.

2. The apparatus of claim 1, wherein the insulating base plate is made of an alumina ceramic material.

3. The apparatus of claim 1, wherein the pressure sensor is made of SiCN ceramic material.

4. The apparatus for measuring impact force of filament bundle and air flow in flash spinning process as claimed in claim 1, wherein the pressure sensor has a piezoresistive coefficient of 1000-3500.

5. The apparatus of claim 1, wherein the pressure susceptor is in the form of a cylinder adapted to the shape of the cylindrical grooves.

6. The apparatus of claim 1, wherein the brush is made of a graphite material.

7. The apparatus of claim 1, wherein the brush is in the form of a fan-ring cylinder.

8. The apparatus for measuring the impact force of the filament bundle and the air flow in the flash spinning process according to claim 7, wherein the size of a central angle corresponding to a cross-section arc of the electric brush is between 45 and 75 degrees, and the arc width of the electric brush is between 16 and 30 mm.

9. The apparatus of claim 1, wherein the inner annular region has an arc width of 40-80mm and the protrusions have a top surface diameter of 40-60 mm.

Technical Field

The invention relates to the technical field of spinning and non-woven fabric preparation, in particular to a device for measuring impact force of tows and air flow in a flash spinning process.

Background

The flash spinning technology mainly comprises the following processes: dissolving high molecular polymer in solvent to form high molecular solution, spraying the solution from spinneret orifice into medium area with different temperature or pressure to form liquid stream, flash evaporating the solvent in the stream to change the form of the original stream and take away heat, cooling the solute, i.e. high molecular polymer, after precipitation to form solvent airflow and filament bundle with superfine three-dimensional network structure, and depositing and collecting the filament bundle by some method to obtain non-woven fabric.

The principle of the conventional flash spinning device is shown in fig. 1, the above main processes occur in a box 1, the polymer solution is pumped into a spinning device 2, passes through an internal pressure reducing plate 3, enters a low temperature and pressure area 4 with lower temperature or pressure than before, the polymer solution starts to phase separate, then is ejected from a spinneret orifice 5 to an environment with lower temperature or pressure to form a filament bundle 6 with an ultrafine three-dimensional network structure, in order to better collect the filament bundle 6 with the three-dimensional network structure, a deflection plate 7 rotating along with a rotating shaft 15 arranged on a bearing 14 deflects the filament bundle and solvent gas flow to the direction of a collecting surface 9 driven by a driving shaft 16, the filament bundle is dispersed into a flat network structure with certain width, namely a filament bundle net 19, because the reaction force of the deflection plate, and the area where the deflection plate collides with the filament bundle has a special profile (not shown in the figure), the tow web is caused to oscillate at a certain amplitude and frequency in a direction perpendicular to or at a certain angle to the direction of movement of the collecting surface in the plane of the contact surface of the deflector plate with the tow (the fibers in the tow web are further opened by being charged like they are midway or by electrostatic treatment, not shown in the figure). The web of filaments is deposited relatively uniformly on a collecting surface in the manner described above to form a nonwoven precursor 10, which is passed through a sealing roll 11, a forming roll 12 and optional further processing steps not shown in the figure to obtain a finished nonwoven 13. The solvent gas passes through the aperture 20 to the recovery unit.

In above-mentioned traditional production process, the air current produces the impact force with the silk bundle to the surface of deflector together, because the silk bundle is dispersed into flat network structure by the reaction force of deflector, so the size of this impact force when production speed changes fluctuates and has directly influenced the dispersed even degree of silk bundle net, and then influenced the unit area quality degree of consistency of final product, and this impact force can't be by direct measurement, can't change other parameters with reference to the impact force, thereby can't play better control to the unit area quality degree of consistency of producing finished product.

Disclosure of Invention

Technical problem to be solved

In order to solve the problems in the prior art, the invention provides a device for measuring the impact force of tows and air flow in the flash spinning process, which can better control the quality uniformity of finished products in unit area.

(II) technical scheme

In order to achieve the purpose, the invention adopts the main technical scheme that: an apparatus for measuring the impact of a tow on an air stream during flash spinning, comprising: the device comprises an insulating bottom plate, a pressure sensor, an electric brush, a constant force spring, a resistance meter and a lead;

the insulation base plate is of a cylindrical structure, one bottom surface of the insulation base plate faces the moving direction of the filament bundles, the center of the other bottom surface is connected with a rotating shaft of a flash spinning device, an annular cylindrical groove is formed in the filament bundle facing surface of the insulation base plate and used for receiving the pressure sensor, the groove is wound on a cylindrical protrusion, the pressure sensor is made of piezoresistive material, the pressure sensor is embedded in the groove and rotates along with the insulation base plate, the surface of the pressure sensor is divided into an inner annular area and an outer annular area, the inner annular area is used for receiving impact force to generate change of resistance value, the outer annular area is in contact with two electric brushes, the electric brushes are pressed on the outer annular area by the constant force spring, and the constant force spring ensures that the pressure of the electric brushes on the surface of the pressure sensor is uniform, the electric brush does not rotate along with the deflection device and the pressure sensor, the resistance meter is electrically connected with the electric brush through the lead, and the resistance meter is matched with the electric brush to measure the resistance value of the pressure sensor.

(III) advantageous effects

The invention has the beneficial effects that: the deflection device in the background art is improved from a deflection plate to a combination of an insulating base plate and a baroreceptor. The pressure sensor made of piezoresistive material is measured by the electric brush, the wire and the resistance meter to generate resistance change after receiving the impact force of the filament bundle and the air flow, the impact force is obtained, the compression resistant distance of the insulating bottom plate is adaptively changed, the impact force is stabilized, the dispersed uniformity of the filament bundle net is improved, and the unit mass uniformity of the flash spinning non-woven fabric is finally improved.

Drawings

FIG. 1 is a schematic structural diagram of a conventional flash spinning apparatus in the background of the present invention;

FIG. 2 is a schematic structural diagram of a device for measuring impact force of tows and air flow in a flash spinning process, which is mounted to a flash spinning device, according to the present invention;

FIG. 3 is a top cross-sectional view of the apparatus for measuring the impact of the filament bundle and gas flow during flash spinning according to the present invention;

FIG. 4 is a right side view of the apparatus for measuring the impact of the filament bundle and gas flow during flash spinning according to the present invention;

FIG. 5 is a schematic structural view of a constant force spring of the device for measuring impact force of filament bundles and air flow in the flash spinning process;

FIG. 6 is a schematic structural diagram of a resistance meter of the device for measuring impact force of filament bundle and air flow in flash spinning process according to the present invention;

[ description of reference ]

1. A box body; 2. a spinning device; 3. a pressure reducing plate; 4. a low temperature pressure region; 5. a spinneret orifice; 6. tow;

7. a deflection plate; 70. an insulating base plate;

8. a baroreceptor; 9. collecting the noodles; 10. a nonwoven fabric precursor; 11. a sealing roller; 12. a forming roller; 13. finished non-woven fabrics; 14. a bearing; 15. a rotating shaft; 16. a drive shaft; 17. an electric brush; 18. a wire; 19. a tow net; 20. an aperture;

51. an inner fixed end; 52. an outer end;

61. and (4) a resistance meter.

Detailed Description

For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.

Referring to fig. 2 to 6, an apparatus for measuring impact force between filament bundle and air flow in flash spinning process includes: the device comprises an insulating bottom plate, a pressure sensor, an electric brush, a constant force spring, a resistance meter and a lead;

the insulation base plate is of a cylindrical structure, one bottom surface of the insulation base plate faces the moving direction of the filament bundles, the center of the other bottom surface is connected with a rotating shaft of a flash spinning device, an annular cylindrical groove is formed in the filament bundle facing surface of the insulation base plate and used for receiving the pressure sensor, the groove is wound on a cylindrical protrusion, the pressure sensor is made of piezoresistive material, the pressure sensor is embedded in the groove and rotates along with the insulation base plate, the surface of the pressure sensor is divided into an inner annular area and an outer annular area, the inner annular area is used for receiving impact force to generate change of resistance value, the outer annular area is in contact with two electric brushes, the electric brushes are pressed on the outer annular area by the constant force spring, and the constant force spring ensures that the pressure of the electric brushes on the surface of the pressure sensor is uniform, the electric brush does not rotate along with the deflection device and the pressure sensor, the resistance meter is electrically connected with the electric brush through the lead, and the resistance meter is matched with the electric brush to measure the resistance value of the pressure sensor.

The invention executes the following steps when the pressure measurement is carried out: under the flash spinning conditions (such as temperature, air pressure, rotating speed of an insulating bottom plate and the like) required to be measured, the function corresponding relation between the resistance of the pressure sensor and the pressure applied to the pressure sensor is measured in advance through the resistance meter and the electric brush, the resistance value of the pressure sensor is measured through the resistance meter and the electric brush in actual production, and the pressure applied to the pressure sensor is compared through the resistance value.

From the above description, the beneficial effects of the present invention are: the deflection device in the background art is improved from a deflection plate to a combination of an insulating base plate and a baroreceptor. The pressure sensor made of piezoresistive material is measured by the electric brush, the wire and the resistance meter to generate resistance change after receiving the impact force of the filament bundle and the air flow, the impact force is obtained, the compression resistant distance of the insulating bottom plate is adaptively changed, the impact force is stabilized, the dispersed uniformity of the filament bundle net is improved, and the unit mass uniformity of the flash spinning non-woven fabric is finally improved.

Furthermore, the insulating bottom plate is made of an alumina ceramic material.

From the above description, it can be seen that the alumina ceramic material has better conductivity, mechanical strength and high temperature resistance, so as to satisfy the working requirements of high mechanical strength and high temperature without interfering the pressure calculation.

Furthermore, the pressure sensor is made of SiCN ceramic material.

From the above description, the material of the pressure sensor is SiCN ceramic, and the dielectric temperature characteristics of the SiCN ceramic show a good linear relationship in the microwave frequency band, so that the influence of temperature on pressure detection is reduced.

Further, the piezoresistive coefficient of the baroreceptor is 1000-.

Further, the pressure sensor is in a circular cylinder shape matched with the shape of the groove in the circular cylinder shape.

From the above description, the outer side surface of the pressure sensor and the bottom surface of the insulating bottom plate moving towards the filament bundle are on the same plane, so that the change of the moving track of the filament bundle after contacting the pressure sensor due to the recess or unevenness generated between the outer side surface of the pressure sensor and the bottom surface of the insulating bottom plate is avoided.

Further, the shape of the electric brush is a sector annular cylinder.

From the above description, it can be known that the fan-ring-shaped cylindrical brush has a larger sectional area, which reduces the resistance of the brush, so that the resistance change of the pressure sensor in the measuring process is better reflected, and simultaneously, the pressure of the constant force spring to the pressure sensor through the brush is properly reduced, and the abrasion of the brush is delayed under the condition of stable contact with the pressure sensor.

Furthermore, the size of a central angle corresponding to a section arc of the electric brush is between 45 degrees and 75 degrees, and the arc width of the electric brush is 16-30 mm.

Further, the arc width of the inner annular area is 40-80mm, and the diameter of the top surface of the protrusion is 40-60 mm.

Example one

Referring to fig. 2 to 6, an apparatus for measuring impact force between filament bundle and air flow in flash spinning process includes: an insulating bottom plate 70, a pressure receptor 8, an electric brush 17, a constant force spring, a resistance meter 61 and a lead 18;

the insulation base plate 70 is a cylindrical structure, one bottom surface of the insulation base plate 70 faces the moving direction of the filament bundle, the center of the other bottom surface is connected with a rotating shaft of a flash spinning device, the insulation base plate 70 faces the filament bundle surface and is provided with a circular cylindrical groove for receiving the pressure sensor 8, the groove is wound on a cylindrical protrusion, the pressure sensor 8 is made of piezoresistive material, the pressure sensor 8 is embedded in the groove and rotates along with the insulation base plate 70, the surface of the pressure sensor 8 is divided into an inner annular area and an outer annular area, the inner annular area is responsible for receiving resistance value change, the outer annular area is contacted with two brushes 17, the brushes 17 are pressed on the outer annular area by the constant force spring, and the constant force spring ensures that the pressure of the brushes 17 on the surface of the pressure sensor 8 is uniform, the brush 17 does not rotate with the deflection device and the pressure sensor 8, the resistance meter 61 is electrically connected with the brush 17 through the lead wire 18, and the resistance meter 61 is matched with the brush 17 to measure the resistance value of the pressure sensor 8.

Specifically, as shown in fig. 5, the constant force spring is made of SUS301 stainless steel, and has an inner fixed end 51 at one end and an outer end 52 at the other end for applying a constant force to the brush 17.

Specifically, as shown in fig. 6, the resistance meter 61 is connected to the brushes 17 spaced apart from each other on the baroreceptor 8 in fig. 3 through the wires 18 at both ends.

Wherein, the insulating bottom plate 70 is made of alumina ceramic material.

Wherein, the pressure sensor 8 is made of SiCN ceramic material.

Wherein, the piezoresistive coefficient of the pressure sensor 8 is 1000-3500.

Wherein the pressure receptor 8 is in the shape of a circular cylinder which is matched with the shape of the groove of the circular cylinder.

Wherein, the electric brush 17 is made of graphite material.

Wherein, the shape of the brush 17 is a fan-shaped annular cylinder. The sector annular cylinder electric brush 17 has a larger sectional area, reduces the resistance of the electric brush 17, better reflects the resistance change of the pressure sensor 8 in the measuring process, properly reduces the pressure of the constant force spring to the pressure sensor 8 through the electric brush 17, and delays the abrasion of the electric brush 17 under the condition of stable contact with the pressure sensor 8.

The test shows that the central angle corresponding to the arc of the cross section of the electric brush 17 is 45-75 degrees, and when the arc width of the electric brush 17 is 16-30mm, the preferred selection range is that the proportion of the area where the resistance of the pressure sensor 8 does not change (namely the outer annular area of the pressure sensor 8) needs to be increased when the cross section of the electric brush 17 is continuously increased, so that the resistance change rate of the whole pressure sensor 8 is reduced after being pressed, and the resistance measurement accuracy is not favorable.

Wherein, the arc width of the inner annular region (i.e. the part of the pressure sensor 8 which is responsible for receiving the impact force and generating the resistance change) is 40-80mm, and the diameter of the top surface of the bulge is 40-60mm, which is preferable.

To better illustrate that the uniformity of the mass per unit area of the finished product is improved when the production process parameters are changed by the method, the non-woven fabric product is produced by adopting the conventional equipment shown in fig. 1 and the improved equipment shown in fig. 2 under the same production speed change condition, and the percentage of the coefficient of variation of the mass per unit area of the non-woven fabrics produced by the two equipment is compared under the GB/T24218.1-2009 standard. Lower coefficient of variation indicates better uniformity of the nonwoven produced.

The same batch of trichlorofluoromethane solution of polyethylene is used as flash spinning raw material, and the existing equipment (marked as equipment A) mentioned in the background art in FIG. 1 and the equipment (marked as equipment B) modified by the technology in FIG. 2 are used for production, the spinning speed of the two spinning equipment is set to rise at the speed of 100m/min within the range of 10000-15000m/min, and other parameters are the same and unchanged. The non-woven fabrics of 40g/m2, 50g/m2, 60g/m2 and 70g/m2 are respectively produced, and in the process of changing the spinning speed, the equipment shown in the figure 2 can dynamically adjust the distance between the spinning device 2 and the deflecting device according to the measured impact force of the tows and the air flow on the pressure sensor 8, so that the impact force is always stable. The apparatus of fig. 1 cannot be adjusted accordingly because the change in impact force cannot be measured. The uniformity of the produced nonwoven fabrics was compared with the percentage coefficient of variation per unit area mass in GB/T24218.1-2009, and the results are shown in the following table.

It can be seen that the apparatus B, i.e. the apparatus equipped with the apparatus of the present invention, is superior to the conventional apparatus A in both the average mass per unit area and the coefficient of variation. The device provided with the device can improve the quality uniformity of finished products in unit area when the production speed changes. Therefore, the flash spinning equipment provided by the invention can adjust the production speed without influencing the product quality in the production process, and has a good effect on the process control of actual production.

In addition to the above embodiments, the impact force of the filament bundle and the air flow on the deflection device is stabilized by adjusting the distance between the spinning device and the deflection device, and other methods (e.g., air pressure, temperature, etc. of the spinning environment) of changing the flash evaporation speed may also be used to control the impact force of the filament bundle and the air flow on the deflection device, so as to achieve the product effect control similar to the above embodiments.

In summary, the device for measuring the impact force of the filament bundle and the airflow in the flash spinning process provided by the invention improves the deflection device in the background art from a deflection plate into a combination of an insulating base plate and a pressure sensor. The pressure sensor made of piezoresistive material is measured by the electric brush, the wire and the resistance meter to generate resistance change after receiving the impact force of the filament bundle and the air flow, the impact force is obtained, the compression resistant distance of the insulating bottom plate is adaptively changed, the impact force is stabilized, the dispersed uniformity of the filament bundle net is improved, and the unit mass uniformity of the flash spinning non-woven fabric is finally improved.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to the related technical fields, are included in the scope of the present invention.