JPH04505121A - Equipment for removing contaminant deposits from the dielectric surface of electrostatic charge target electrodes - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] BACKGROUND OF THE INVENTION Apparatus for removing contaminant deposits from the dielectric surface of an electrostatic target electrode 1. Field of invention The present invention is a method for attracting target electrodes used to electrostatically charge fibrous tissue. Regarding equipment for cleaning the surface of electric bodies during the process, more particularly for multi-fiber webs, flash spinning (frast+-spinning) followed by charging and diffusion; and during its manufacture by deposition on a moving surface 1°, Tapping during application of electrostatic charge. The present invention relates to an apparatus for removing contaminant deposits accumulated on a target electrode.

2. Prior art and other considerations For expansion and deposition, the spun fibrous tissue has a #1 charge. Flash spinning of multifilament webs of interconnected fibrous filaments Methods and apparatus for flash-spinning are known in the art.

George's U.S. Pat. No. 3,578,739 is a flash-span (pun) discloses an apparatus for imparting an electrostatic charge to a fibrous tissue, in which the fibrous tissue The weave passes through the charged band between the corona discharge electrode and the target electrode, and the target The pole has a conductive base and a high resistance surface coating. flash spinning (fr) ash-spinning) and electrostatic charging of fibrous tissues. The problem-generating action, that is, it is attracted to the target electrode and creates an electrically binding film on it. A high resistance dielectric surface coating is provided to avoid reducing the formation of small isolated particles. It will be done. If the voltage drop across this film exceeds its dielectric strength, damage will occur and the Indentation is created and the charge on the fibrous structure is accompanied by degradation and loss of process performance. It causes "back corona" which causes harmony. High resistance dielectric surface coating is outside the charging area This reduces the current density, which increases the magnitude of the current drawn to the failure point. limit the amount of to prolong the effects of target electrode contamination by particle deposits. Previous procedures such as rotation of the target electrode may remove particles from the target electrode surface. Use of a scraper to remove and conductive liquid onto the rotating target surface Continuous eradication of is discussed in George's patent. Therefore, U.S. Pat. The device of No. 578,739 eliminates undesirable target electrode contamination due to particle deposition. Reduce impact.

Dielectric surface coating of the target electrode discussed by George in the aforementioned patent. provides considerably improved performance at processing speeds commonly used in the past. . Increased production rates and therefore flash-spun IIM fibers Demand increases as increased texture production rates are achieved through increased formation of contaminated deposits. Add. Furthermore, increased production rates required higher charging current densities. As a result, target electrodes become contaminated more rapidly than in the past. Therefore, George The resulting treatment, like the teachings of the aforementioned patents, is when operated, especially due to the rapid growth of contaminant deposits and the associated loss of charging efficiency. It was found that the target electrode could only provide a relatively short effective operating time. It was.

U.S. Pat. No. 3,860,369 to Presauer et al. also discloses an apparatus for making nonwoven fiber threads. This is preferably a dielectric insulator disclosed in U.S. Pat. No. 3,578,739. Web in the corona discharge zone with a metal target disk electrode covered with an edge surface contains an electrostatic charge. Presauer et al. Figure 3 shows the use of a rotating brush for cleaning the pieces.

The present invention provides a target electrode that provides a relatively short effective operating life of the target electrode surface coating. Before being caused by ultra-flash-spun fine-grain deposits It is intended to substantially reduce the problems described above, and the present invention therefore provides a Provides self-cleaning rotating brushes that remove contaminant deposits from surfaces, thereby cleaning The target electrode has a significantly longer useful working life than previously possible. The primary objective is to achieve the desired goal.

Summary of the invention The principles of the present invention allow flash spinning of fibrous web structures. contains small solidified polymer particles created during spinning (spinning) and electrostatic charging. However, areas of accumulated contaminant deposits on the target electrode are removed by a self-cleaning rotating brush device. This removes contaminant deposits and increases the electrical charge on the fibrous web structure. Efficiency is improved and therefore the useful working life of the target electrode is increased considerably.

The device of the present invention scrapes the tip along the rotating target electrode surface. A cylindrical brush with substantially radial bristles that removes deposits from the Equipped with The brush is rotated about its central axis and is exposed to a moving target electric current. Adjustable spring loading is applied to the polar surface. The brush was gathered on the bristles Continuously cleaned by rubbing against cleaning zelkova to remove contaminated deposits .

Brief description of the drawing These and other objects, features and advantages of the present invention are illustrated in the accompanying drawings. It will be clear from the following more specific description of the preferred embodiment of the invention and shown in the drawings. Like numbers refer to like parts throughout the figures. The drawing is schematic The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

FIG. 1 shows a flash-spinning machine including a brush device according to the invention. 1 is a schematic cross-sectional elevational view of a pinning device; FIG.

Figure 2 is a part of Figure 1 schematically showing the vicinity of the target electrode contaminated by deposits. It is a schematic enlarged view.

rXJ3 is a schematic, enlarged cross-sectional view of a brush device according to the principles of the present invention;

Description of the preferred embodiment Referring to Figure 1, flash spinning used to produce multifilament web structures. A (flash-spinning) device 10 is shown diagrammatically. The device shown is , comprising charging means for electrostatically charging such structure. Charging means is an Oine gun 12 and a target electrode 14, the latter being generally formed in the form of an annular disk. . A dielectric surface layer 16 is provided on the target electrode 14 and a dielectric surface layer 16 is provided around the baffle 18. arranged concentrically. Baffle 18 rotates around central axis 20 as shown by arrow 22. It is rotated by In the spinneret 24, the fibers exit from the orifice 28 and form a fibrous structure 26. A pressurized polymer solution is supplied. The aerodynamic seanoside has a first member 30 and a second member 30. A member 32 is provided.

Target electrode J4 rotates together with second member 32 independently of baffle 18. 62 is made concentric with this by means not shown. collection an endless belt 3 whose surface 34 is supported by the rolls of a motorized vehicle 38; Be prepared for G.

The fibrous tissue 26 coming out of the orifice 28 is caused by the influence of aerodynamic forces and the surface of the baffle 18. Due to the shape of the From this point, it is warped between the first and second shield members 30 and 32, and continues to move. It continues moving towards and onto the collecting surface 34.

The ion gun 12 equipped with the first shield member 3o has a voltage of 5o to 100kV. is supplied. The target electrode 14 includes a contact ring and brush device (not shown). It is electrically connected to ground via. Corona discharge is generated on the ion gun 12 and the target electrode. 4 and continuously charges the fibrous tissue 26, thereby inhibiting its diffusion. make me wake up Collection surface 34 is electrically conductive and is grounded or connected to fibrous tissue 26. charged with opposite polarity.

Thus, the fibrous tissue 26 is drawn onto the collection surface 34 in the form of a flattened sheet. and transported by a motorized transport means 38 to an accumulation means 42.

Production of non-woven sheets from continuous fibrous structures in an apparatus such as that shown above in Figure 1. In order to maintain the diffusion of the partially interconnected filaments and collecting surface 3. 4 to effectively deposit the tissue in a flat form on the fibrous tissue 26. A specific charge is required. The electrostatic charge is generated when the fibrous tissue 26 is connected to the ion gun 12 and the target. is applied to it while passing between it and the part of the electrode 14 closest to it.

Fibrous tissue 26 passes through a monopolar portion formed on the surface of target electrode 14 . The monopolar part is connected to the corona discharge device, i.e. from the ion gun 12 to the target electrode 14. Established by the flow of ions. The electric charge acquired by the fibrous tissue 26 is transferred to the ion gun 12. has the same polarity as the charge. Charges of the same polarity are applied to the components of the fibrous tissue 26. Coulomb repulsion causes this component to diffuse.

generated as a byproduct of flash-spinning The small solidified polymer particles as well as the small solidified polymer particles exiting the spinneret 24 It is charged by ions sent from the ion gun 12. Charged fibrous tissue 26 The charged polymer particles It is attracted to and preferentially deposits on dielectric surface layer 16.

The brush device 45 extends from the charging region between the ion gun 12 and the target electrode 14. placed in the area. The particle-contaminated surface area of the dielectric surface layer 16 is located at the annular target electrode 1. 4, the deposited particles are brought within the reach of the brush device 45, and the deposited particles are brushed. It is removed by washing.

Referring to FIG. is deflected downward and passes through the charged region between the ion gun 12 and the target electrode 14. It continues to move downward and is carried to a collection surface that is charged to the opposite polarity. Target electrode 14 comprises a metal target base 48 and a dielectric surface layer 16. First v! to J1 As explained in connection, small charged polymer particles are deposited on the dielectric surface layer 16. The contaminant layer 50 is formed thereon. The growth of the contamination layer 50 is due to the charging process. This is harmful and rapidly reduces charging efficiency. Therefore, prevention or erasure of the contamination layer 50 is extremely difficult. highly desirable.

Contaminant layer 50 is a non-conductive film on target electrode 14. of this film The thickness and therefore the voltage drop across it increases until the voltage drop exceeds the breakdown voltage. Then, the film is destroyed. This creates a small indentation and 'rona' discharge occurs. Ions created by the back corona exhibit unipolarity in the charged region. This causes a loss of charge available to the fibrous tissue 26. to this It will be appreciated that the effects of electrostatic charges are considerably reduced.

This difficulty was first recognized in technologies associated with bare metal target electrode actuation. , as disclosed, for example, in the above-cited U.S. Pat. No. 3,578,739. It was somewhat alleviated by the installation of a high resistance layer coating on the metal target. but, The high-resistance layer coating revealed in this study can extend the effective operating time of the target electrode. Although this alleviates the difficulty somewhat, the accumulation of a layer of contaminant particles on the target electrode remains a problem. This remains a problem and the extension of the useful life of the target electrode is severely hampered by this.

Virtually eliminates this problem, thereby greatly extending the useful life of the target electrode. Therefore, the present invention provides the above-mentioned brush device 45 for removing the contaminant layer 50 during the process. Ru.

Now, referring to FIG. 3, a brush device spaced apart from the target electrode 14 is shown. A location 45 is shown. The target electrode 14 has the general shape of an annular ring and is made of metal. It includes a target base 48 and a dielectric surface layer 16. The target electrode 14 The rotating baffle 18 is arranged concentrically around the rotating baffle 18, and rotates independently around its central axis. Turn around. The brush device 45 is connected to a shaft 54 rotatably supported by a gear box 56. A fixed brush assembly 52 is disposed between the support 60 and the gearbox 56. A compression spring loading device 58 is attached to the gearbox 56 and supports an adjustment support 64 compression adjustment means 62 and a cleaning rod 66 supported by the gear box 56. Equipped with The brush cleaning rod 66 can be stationary, but preferably at its center. rotated around an axis. Shaft 54 extends through gearbox 56 as shown; It is driven by a power drive means (not shown), for example a flexible drive shaft. brush cleaner When the sweep rod rotates, it is driven by the shaft 54 via gears in the gear box 56. and to further aid in cleaning and cleaning the bristles of the brush assembly 52, this Although other cross-sectional shapes can be used effectively for this purpose, a substantially triangular cross-sectional shape It is preferable to do so.

The support 60 and the adjustment support 64 are provided by flash-spinning. ning) rigidly attached to a structural member (not shown here) of the device. .

The gearbox 56 has a pivot axis parallel to the axis 54 and has a flash spinning (fr is pivotally attached to a structural member of the ash-spinning) device 10 and The brush assembly is then moved against the dielectric surface layer 16 by the action of the compression spring loading device 58. Substantially tangential contact along the length of 52 is maintained while brush contact is anticipated. The reserve load is selectively adjusted by compression adjustment means 62.

Therefore, the pivotable mounting of the gearbox 56 is useful for its maintenance and similar purposes. from contact with the dielectric surface layer 16 of the brush assembly 52. It is convenient for withdrawal. The removal of the compression spring loading device 58 from contact is required under the circumstances. It will be understood that this will be required.

Brush assembly 52 preferably includes a plurality of bristles having substantially radially oriented bristles. It includes cylindrical brushes 68, which are assembled on the shaft 54, e.g. It is secured to this by a sea urchin nut and locking assembly.

For example, each cylindrical brush has a width of 0.76 cm, a diameter of 6.4 cta, and approximately 2000 It is equipped with solid nylon fiber bristles, each bristle having a diameter of 0.041 cm.

In use of the brush device 45, the brush assembly 52 is elastically disposed on the dielectric surface layer 16. The brush is between about 0 and 0.51 cm, preferably about 0.1 and 0.25 cm. and the brush contact preload provided by the cover spring loading device 58. to the compression adjusting means 62 so that the weight is between 0.68 and 3.41 to 3.64 kg. More adjusted. The shaft 54 is driven such that the bristle tip speeds are approximately 50.8 and 63.5c. m/s to about 150 to 190 rpm, preferably about 170 rpm+ It is rotated by m. The brush cleaning rod 66 is parallel to the shaft 54 and has a rigid distance from it. Disposed at a distance that causes elastic brush contact interference between the bristles and the surface of the brush cleaning rod 66. be done. This contact interference is caused by particles collected on the bristles due to brushing off the bristles. The practical removal of particles caused by

Flash-spinning equipment 2101 The use of the rasp device 45 effectively removes the contaminant layer 50 from the dielectric surface layer 16. This considerably extends the working life of the target electrode 14. As mentioned above, the brush Since the tray 45 cleans itself by the action of the brush cleaning rod 66, there is no need for its own maintenance. The operating life of flash-spinning equipment is 10 Significantly exceeds the lifespan of critical components. Without the use of a brush device for removing the contaminated layer The lifespan of the dielectric surface during working operation when using the brush device according to the principle of the present invention , was found to have increased by at least about 2.5 times.

Although the present invention has been particularly illustrated and described with respect to its preferred embodiment, it is within the spirit of the invention. and may make various changes and modifications in form and detail without departing from the limits. It will be understood by those skilled in the art.

FIG. 2 international search report

Claims (7)

[Claims] 1. In flash-spinning equipment, static An apparatus for removing contaminant deposits from a dielectric surface of a charge target electrode; a brush assembly having multiple bristles for removing said contaminant deposits from electrical surfaces; , the brush assembly brushes away the contaminant deposits and supports them on the plurality of bristles; The plurality of bristles are arranged substantially radially within a cylindrical profile and the brush assembly The body is fixed concentrically to the rotating shaft, and includes a brush cleaning rod for bristle cleaning, the brush cleaning rod are spaced radially from the rotating shaft, and the brush cleaning rod is spaced apart from the plurality of brush cleaning rods. contact with the bristles of the bristles, thereby removing the contaminant deposits from the bristles, and removing the contaminant from the bristles. The brush cleaning rod is used in conjunction with the bristles to remove the contaminant deposits. acts on sea urchins, and a contaminated deposit comprising a gearbox in which the rotating shaft and the brush cleaning rod are supported; removal device. 2. In a flash-spinning device, the front The bristle tip velocity of the bristles is approximately 50.5 mm at the cylindrical outer circumference of the brush assembly. Claim 1: The rotating shaft is driven at a speed ranging from 8 to 63.5 cm/s. device by. 3. In a flash-spinning device, the front a pivoting mounting arrangement for the gearbox, whereby the brush assembly is mounted on the dielectric body; It is rotatable so as to engage with the surface and further detach from it, Applying a preload to the gearbox, which causes the brush assembly to be in contact with the contact assembly. a compression spring loading device for preloading the brush assembly and the brush assembly; adjustment for selectively adjusting the magnitude of interference in said contact combination with a dielectric surface; The apparatus of claim 1 further comprising adjusting means. 4. In a flash-spinning device, the front A preload of the gearbox by the compression spring loading device is applied to the brush assembly and front. A claim for adding a preload between 0.68 and 3.64 kg between the dielectric surface and the dielectric surface. Device according to item 3. 5. In a flash-spinning device, the front such that the interference in the contact combination is within a range between 0 and 0.51 cm. Device according to adjusted claim 3. 6. In a flash-spinning device, the front The brush cleaning rod has a string around its longitudinal axis to stabilize the cleaning effect of its bristles. The gearbox is driven to rotate, and the gearbox has teeth that rotate the brush cleaning rod. A device according to claim 1 comprising a vehicle device. 7. In a flash-spinning device, the front The brush cleaning rod has a substantially triangular cross-sectional shape to further increase its cleaning effect. A device according to claim 6 having: