EP0560869A1 - A method of producing fibres from mineral melt with the aid of centrifugal force - Google Patents

A method of producing fibres from mineral melt with the aid of centrifugal force

Info

Publication number
EP0560869A1
EP0560869A1 EP19920900947 EP92900947A EP0560869A1 EP 0560869 A1 EP0560869 A1 EP 0560869A1 EP 19920900947 EP19920900947 EP 19920900947 EP 92900947 A EP92900947 A EP 92900947A EP 0560869 A1 EP0560869 A1 EP 0560869A1
Authority
EP
European Patent Office
Prior art keywords
spinning wheel
spinning
fibre
wheel
melt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19920900947
Other languages
German (de)
French (fr)
Inventor
Timo Olavi Hoikka
Erik Axel Astrand
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Paroc Hold Oy AB
Original Assignee
Paroc Oy AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Paroc Oy AB filed Critical Paroc Oy AB
Publication of EP0560869A1 publication Critical patent/EP0560869A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/04—Manufacture of glass fibres or filaments by using centrifugal force, e.g. spinning through radial orifices; Construction of the spinner cups therefor
    • C03B37/05—Manufacture of glass fibres or filaments by using centrifugal force, e.g. spinning through radial orifices; Construction of the spinner cups therefor by projecting molten glass on a rotating body having no radial orifices
    • C03B37/055—Manufacture of glass fibres or filaments by using centrifugal force, e.g. spinning through radial orifices; Construction of the spinner cups therefor by projecting molten glass on a rotating body having no radial orifices by projecting onto and spinning off the outer surface of the rotating body

Definitions

  • This invention relates to a method of producing fibres from mineral melt with the aid of centrifugal force.
  • the method is especially directed to controlling vibration conditions on the fibre producing surface/s of a spinning wheel unit employed for producing fibres from mineral melt.
  • the invention is described below in connection with a so-called cascade spinner, but it can also be used with all prior art defibration methods where the centrifugal force plays a determining role at the initial stage of the fibre generation.
  • a cascade spinn ⁇ er normally consists of two to four spinning wheels, each forming a unit with a driving axle, devices for the supp ⁇ ly of air, cooling agent, binding agents and possible other additives.
  • the spinning wheels are normally installed onto a movable carriage.
  • Fibre generation takes place as follows: the mineral melt is supplied onto the peripheral surface of the first spinning wheel unit from which it is thrown in a drop cascade form onto the next spinning wheel located at a slight angle below and from there onto the peripheral surface of the next and subse ⁇ quent spinning wheels.
  • the number of spinning wheels is usually four, but it may be more or less.
  • the mineral melt fixes onto the peripheral surface of each spinning wheel in a ribbon form. Fibre embryos are thrown out of this melt ribbon and are drawn into fibres with the aid of jets of air.
  • the fibres are collected onto a receiving conveyor and are formed into a mat.
  • the said uncertainty factor caused by the spinning wheel suspension can be essentially eliminated by providing the spinning wheel with non-contact magnetic bearings.
  • This enables the control of the spinning wheel's rotation movement and allows the rotation of the spinning wheel or wheels with the centre of mass as the rotation centre.
  • This is due to the fact that the centre of mass is shift ⁇ ed from the centre of the wheel as a result of the un ⁇ steady distribution of material around the spinning wheel - one of the results of fibre generation process.
  • This .imbalance cannot be eliminated when using mechanical spinning wheel bearings; instead, the vibration caused by the difference between the centre of mass and the rota ⁇ tion centre will continuously disturb the fibre gener- ation process.
  • the vibration directed at the melt surface causes a wave phenomenon with the peaks serving as embryos for the fibres being generated.
  • the main pur ⁇ pose of this invention has been to conceive a method for controlling this wave phenomenon.
  • a primary precondition for the functioning is, however, that uncontrolled vibra ⁇ tions are entirely eliminated from the spinning wheel rotation movement.
  • the essential step is to control the spinning wheel's magnetic bearings into a vibrationless basic rotation state where the rotation centre is located in the center of mass. Once this is accomplished, it becomes possible to control the spinning wheel vibrations and use them for regulating the distri ⁇ bution of the fibre being generated.
  • the aim in fibre generation is to accomplish a distribution of fibres with a dominating thickness of 2 - 6 ⁇ m. The intention is to avoid the generation of thinner and thicker fibres re- spectively.
  • the fibre generation is controlled by accomplishing con ⁇ trolled vibrations in the spinning wheel.
  • These vibra- tions produced in the spinning wheel may be directed radially or axially and can be caused alternatively or simultaneously.
  • the vibration amplitude is restricted to the magnetic bearing's degree of freedom; in practice this restriction is to approx. 1 mm.
  • Fig. 1 shows a front view of a spinning wheel unit with the melt ribbon on the peripheral surface of the spin ⁇ ning wheel, and the spinning wheel's geometric centre and the centre of mass marked
  • Fig. 2 a) - c) shows the invention's control alterna ⁇ tive where high frequency radial vibrations are direct ⁇ ed onto the spinning wheel
  • Fig. 3 shows a schematic control system for a spinning machine in accordance with the invention including four spinning wheels (the control circuit for a possible fifth spinning wheel is drawn using dashed lines in the lower part of the figure) , and
  • Fig. 4 shows a schematic control circuit for a spin ⁇ ning axle
  • Fig. 5 shows a schematic end view of a spinning wheel with a control system for the magnetic bearings pro ⁇ vided with the corresponding descriptions of the con ⁇ trol circuit components in Fig. 4.
  • Figure 1 shows a cascade spinner with each of the spinn ⁇ ing axles suspended using at least one magnetic bearing.
  • the thickness of the melt ribbon on the spinning wheel's peripheral surface has, however, been exaggerated. It mainly shows the correct proportion of the ribbon thick ⁇ ness at different points of the peripheral surfaces and on different spinning wheels.
  • the spinning wheels' geo- metric centre has been indicated with rp.
  • the spinning wheel's centre of mass has been indicated with mp. It is .easy to see that the varying thickness of the melt ribbon on the peripheral surfaces and the pulsing melt stream into the fibre generation device cause a displacement of the mass centre.
  • By using magnetic bearings for axle sus ⁇ pension the wheel's rotation axles are shifted from the geometric centre to the wheel's centre of mass. With this arrangement, steady and vibration-free rotation is achieved, which is the primary precondition for the method in accordance with this invention.
  • Figure 2 a shows an example of the bearing's radial con ⁇ trol value in the direction of an opposite pair of coils (e.g. 61, 61 in figure 5) where the bearing during an axle revolv actively prevents load changes from occurring and keeps the rotation centre within the system's centre of mass (by changing the bearing forces on opposite sides of the axle) .
  • FIG 2 b) shows an example of a high frequency vibration intended to be directed to the axle in the direction of an oppo- site pair of bearings.
  • the control signal for one of the above axle's coil pairs in accordance with the figure 2 c) during the same revolv as shown in figure 2 a).
  • the vibration ampli ⁇ tude on the y-axle is shown in mm.
  • control system includes two main cat- egories of control; a control circuit for the spinning machine and separate control circuits for the spinning machine's spinning wheels.
  • Fig. 3 shows a schematic control circuit for the spinning machine.
  • the spinning machine's control device 31 is provided with continuous fibre generation variable data supplied to the system from the fibre process detectors.
  • the fibre gener ⁇ ation variables indicate, among other things, the various properties of the melt, such as temperature, viscosity, surface tension, and other concrete fibre generation values from the end-product, etc.
  • the control circuit supplies control information 33 with regard to tempera- ture, vibrations, positions, powers, etc.
  • the spinning axle control circuits 32 also supply signals 35 to the spinning machine control circuit. These signals may indicate the load imposed by the melt cascade on the magnetic suspension, the power consumption of spindle drive motors, position data, etc.
  • FIG 4 shows in schematic form the part of the spinning axle control circuits used for controlling the magnetic bearings which is thus of importance for this invention.
  • the control circuit is drawn for an axle with two pairs of magnetic coils in each bearing.
  • the magnetic bearing's control circuits are of prior art type and control the current fed to the magnetic coils 61 based on the signals received from position detectors 7 and 9. ⁇
  • control circuit 21 In the radial bearing the control circuit 21 is combined with a balancing circuit 22 used for relaying the rotor rotation onto the retardation axle which is major import ⁇ ance for the generation of fibre from mineral melt on the peripheral surface of a spinning wheel.
  • the axle cooperates with the spinning machine's other axles via the spinning machine control circuit (fig.3) .
  • Control circuit 32' constituting a part of the control circuit 32 in figure 3 has been inserted between the regulating circuit 21 and balancing circuit 22.
  • Control circuit 32' prepares signals for the spinning axles con- tained in the magnetic suspensions.
  • the circuit is in continuous contact with the spinning machine control sys ⁇ tem 31, figure 3, receiving parameter value data from it.
  • the regulating circuit 32' can accept weakened output signals for certain magnetic coils, but can also supply the magnetic coil with control signals for active vibra ⁇ tion of the fibre generating element. This active vibra ⁇ tion can be executed, for example, by amplifying the vol ⁇ untary vibrations or by modifying the counter-acting fre ⁇ quency.
  • the signals handled by the balancing circuit 22 must not, however, be totally ignored, as the material distribution on the spinning wheel would cause an imbal ⁇ ance jeopardizing the whole fibre generation process. Variations of rotor stiffness are actively used for vi ⁇ bration control via the amplifiers' frequency control, but rotor speed variations are not used to a very large extent, as the speed variations are primarily used for fibre generation instead of for seeking critical fre ⁇ quencies.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)

Abstract

L'invention se rapporte à un procédé de commande de la fabrication de fibres par transformation d'une masse minérale fondue en fibres à l'aide d'une force centrifuge. Dans ce procédé, on applique des vibrations contrôlées aux roues du dispositif de fibrage.The invention relates to a method for controlling the production of fibers by transforming a molten mineral mass into fibers using a centrifugal force. In this process, controlled vibrations are applied to the wheels of the fiberizing device.

Description

A method of producing fibres from mineral melt with the aid of centrifugal force
This invention relates to a method of producing fibres from mineral melt with the aid of centrifugal force. The method is especially directed to controlling vibration conditions on the fibre producing surface/s of a spinning wheel unit employed for producing fibres from mineral melt. The invention is described below in connection with a so-called cascade spinner, but it can also be used with all prior art defibration methods where the centrifugal force plays a determining role at the initial stage of the fibre generation.
In a cascade spinner, the fibre generation takes place on the outer periphery of a spinning wheel. A cascade spinn¬ er normally consists of two to four spinning wheels, each forming a unit with a driving axle, devices for the supp¬ ly of air, cooling agent, binding agents and possible other additives. The spinning wheels are normally installed onto a movable carriage. Fibre generation takes place as follows: the mineral melt is supplied onto the peripheral surface of the first spinning wheel unit from which it is thrown in a drop cascade form onto the next spinning wheel located at a slight angle below and from there onto the peripheral surface of the next and subse¬ quent spinning wheels. The number of spinning wheels is usually four, but it may be more or less. The mineral melt fixes onto the peripheral surface of each spinning wheel in a ribbon form. Fibre embryos are thrown out of this melt ribbon and are drawn into fibres with the aid of jets of air. The fibres are collected onto a receiving conveyor and are formed into a mat.
During the defibration of mineral melt, a balance pre¬ vails between the spinning wheel defibration surface, the layer of melt on the spinning wheel and the ambient gas. This state of equilibrium is determined by the conditions between the surface forces, the hydrodynamic fluid forces and the prevailing acceleration forces within the system. If the hydrodynamic, chiefly aerodynamic forces and ac¬ celeration forces exceed a certain value, the melt layer will break forming drops and fibres.
An uncertainty factor at the generation of the said equi¬ librium is caused by the vibrations of the defibration element; i.e. the spinning wheel. These vibrations are difficult to control. The vibrations result in loss of control of the sequence of events turning melt into fibres. These vibrations are at least partly due to the rigid suspension arrangement of the spinning wheel giving rise to sideways forces which adversely affect the con- trol of the fibre generation process. The sideways forces affect the fibre embryo generation on the spinning wheel's peripheral surface as well as the circumstances prevailing just before the onset of favourable conditions for fibre generation.
The said uncertainty factor caused by the spinning wheel suspension can be essentially eliminated by providing the spinning wheel with non-contact magnetic bearings. This enables the control of the spinning wheel's rotation movement and allows the rotation of the spinning wheel or wheels with the centre of mass as the rotation centre. This is due to the fact that the centre of mass is shift¬ ed from the centre of the wheel as a result of the un¬ steady distribution of material around the spinning wheel - one of the results of fibre generation process. This .imbalance cannot be eliminated when using mechanical spinning wheel bearings; instead, the vibration caused by the difference between the centre of mass and the rota¬ tion centre will continuously disturb the fibre gener- ation process.
Uncontrolled vibration of a rotating spinning wheel gives rise to great acceleration forces directed at the melt fibre embryos. In extreme conditions, these forces either strengthen or repel the effect of the centrifugal force. The nominal value of these forces is almost as large as the centrifugal force. The centrifugal force is the main external force during the initial fibre generation stage.
On the other hand, the vibration directed at the melt surface causes a wave phenomenon with the peaks serving as embryos for the fibres being generated. The main pur¬ pose of this invention has been to conceive a method for controlling this wave phenomenon. A primary precondition for the functioning is, however, that uncontrolled vibra¬ tions are entirely eliminated from the spinning wheel rotation movement. In this respect, the essential step is to control the spinning wheel's magnetic bearings into a vibrationless basic rotation state where the rotation centre is located in the center of mass. Once this is accomplished, it becomes possible to control the spinning wheel vibrations and use them for regulating the distri¬ bution of the fibre being generated. The aim in fibre generation is to accomplish a distribution of fibres with a dominating thickness of 2 - 6 μm. The intention is to avoid the generation of thinner and thicker fibres re- spectively.
In accordance with the main principle of this invention, the fibre generation is controlled by accomplishing con¬ trolled vibrations in the spinning wheel. These vibra- tions produced in the spinning wheel may be directed radially or axially and can be caused alternatively or simultaneously.§
Once radial vibrations are accomplished, it becomes poss- ible to make use of the spinning wheel's said basic pro¬ perty; i.e. the difference between its constructive rota¬ tion centre and the center of mass. The rotation center can be intentionally displaced from the centre of mass, which naturally causes a spinning wheel vibration depend¬ ing on the rotation speed. The direction of the vibration amplitude maximum can be controlled around the wheel by regulating the direction of the change in the rotation centre. It is thus possible to direct the vibration am¬ plitude maximum towards an advantageous point on the spinning wheel's periphery; for instance by taking into account the confrontation zone of the melt being suppli- ed.
With the help of the magnetic bearings, it becomes poss¬ ible to direct radial vibrations of essentially higher amplitudes onto the spinning wheel, in stead of or together with the said mass center - rotation center con¬ trol. This vibration has two different effects, depending on the vibration frequency. At lower frequencies of below 100 Hz, the melt route through the group of wheels is mainly affected and thereby also the amount of fibres and their properties. At higher frequencies of up to 500 Hz, the said melt surface wave phenomenon is affected in such a manner that the vibration is in resonance with an ap¬ propriate wave dimension or wave form causing the fibre producing process to start from the selected wave dimen- sion or wave form. The vibration amplitude is restricted to the magnetic bearing's degree of freedom; in practice this restriction is to approx. 1 mm. With the said con¬ trol method it is possible to influence the dimension and form distribution of the fibre being generated. It is possible/expedient also to direct this high frequency vibration purposefully in a certain direction in relation to the melt stream supplied.
In order to accomplish the control, it is necessary to have information concerning the process variables. This is obtained from the detectors used for reading various process variables. The values obtained are compared with the pre-programmed default values, and the existing dif¬ ferences feed impulses to the bearings of the spinning axles for correcting the spinning wheel's rotation points making the values measured comply with the default values.
The following is a description of an advantageous form of implementation for a spinning wheel unit in accordance with this invention, with reference to appended drawings in which
Fig. 1 shows a front view of a spinning wheel unit with the melt ribbon on the peripheral surface of the spin¬ ning wheel, and the spinning wheel's geometric centre and the centre of mass marked
Fig. 2 a) - c) shows the invention's control alterna¬ tive where high frequency radial vibrations are direct¬ ed onto the spinning wheel,
Fig. 3 shows a schematic control system for a spinning machine in accordance with the invention including four spinning wheels (the control circuit for a possible fifth spinning wheel is drawn using dashed lines in the lower part of the figure) , and
Fig. 4) shows a schematic control circuit for a spin¬ ning axle,
Fig. 5 shows a schematic end view of a spinning wheel with a control system for the magnetic bearings pro¬ vided with the corresponding descriptions of the con¬ trol circuit components in Fig. 4.
Figure 1 shows a cascade spinner with each of the spinn¬ ing axles suspended using at least one magnetic bearing. The thickness of the melt ribbon on the spinning wheel's peripheral surface has, however, been exaggerated. It mainly shows the correct proportion of the ribbon thick¬ ness at different points of the peripheral surfaces and on different spinning wheels. The spinning wheels' geo- metric centre has been indicated with rp. The spinning wheel's centre of mass has been indicated with mp. It is .easy to see that the varying thickness of the melt ribbon on the peripheral surfaces and the pulsing melt stream into the fibre generation device cause a displacement of the mass centre. By using magnetic bearings for axle sus¬ pension, the wheel's rotation axles are shifted from the geometric centre to the wheel's centre of mass. With this arrangement, steady and vibration-free rotation is achieved, which is the primary precondition for the method in accordance with this invention.
Figure 2 a) shows an example of the bearing's radial con¬ trol value in the direction of an opposite pair of coils (e.g. 61, 61 in figure 5) where the bearing during an axle revolv actively prevents load changes from occurring and keeps the rotation centre within the system's centre of mass (by changing the bearing forces on opposite sides of the axle) .
If the intention is to programmed change the fibre gener¬ ation conditions, it is necessary to consciously displace the axle of rotation from the mass centre. Figure 2 b) shows an example of a high frequency vibration intended to be directed to the axle in the direction of an oppo- site pair of bearings. Here, it is necessary to generate the control signal for one of the above axle's coil pairs in accordance with the figure 2 c) during the same revolv as shown in figure 2 a). In figure 2 the vibration ampli¬ tude on the y-axle is shown in mm.
It is, of course, possible to cause corresponding (or other) displacements anywhere within the radial x-y level or in the direction of the axial z-axle, also at the same time.
An example of the control system includes two main cat- egories of control; a control circuit for the spinning machine and separate control circuits for the spinning machine's spinning wheels.
Fig. 3 shows a schematic control circuit for the spinning machine.
The spinning machine's control device 31 is provided with continuous fibre generation variable data supplied to the system from the fibre process detectors. The fibre gener¬ ation variables indicate, among other things, the various properties of the melt, such as temperature, viscosity, surface tension, and other concrete fibre generation values from the end-product, etc. The control circuit supplies control information 33 with regard to tempera- ture, vibrations, positions, powers, etc.
The spinning axle control circuits 32 also supply signals 35 to the spinning machine control circuit. These signals may indicate the load imposed by the melt cascade on the magnetic suspension, the power consumption of spindle drive motors, position data, etc.
Figure 4 shows in schematic form the part of the spinning axle control circuits used for controlling the magnetic bearings which is thus of importance for this invention. The control circuit is drawn for an axle with two pairs of magnetic coils in each bearing.
The magnetic bearing's control circuits are of prior art type and control the current fed to the magnetic coils 61 based on the signals received from position detectors 7 and 9. δ
In the radial bearing the control circuit 21 is combined with a balancing circuit 22 used for relaying the rotor rotation onto the retardation axle which is major import¬ ance for the generation of fibre from mineral melt on the peripheral surface of a spinning wheel.
The axle cooperates with the spinning machine's other axles via the spinning machine control circuit (fig.3) .
Control circuit 32' constituting a part of the control circuit 32 in figure 3 has been inserted between the regulating circuit 21 and balancing circuit 22. Control circuit 32' prepares signals for the spinning axles con- tained in the magnetic suspensions. The circuit is in continuous contact with the spinning machine control sys¬ tem 31, figure 3, receiving parameter value data from it. The regulating circuit 32' can accept weakened output signals for certain magnetic coils, but can also supply the magnetic coil with control signals for active vibra¬ tion of the fibre generating element. This active vibra¬ tion can be executed, for example, by amplifying the vol¬ untary vibrations or by modifying the counter-acting fre¬ quency. The signals handled by the balancing circuit 22 must not, however, be totally ignored, as the material distribution on the spinning wheel would cause an imbal¬ ance jeopardizing the whole fibre generation process. Variations of rotor stiffness are actively used for vi¬ bration control via the amplifiers' frequency control, but rotor speed variations are not used to a very large extent, as the speed variations are primarily used for fibre generation instead of for seeking critical fre¬ quencies.

Claims

Patent claims:
1. A method of controlling fibre generation in the manu¬ facture of fibres from mineral melt with the aid of cen- trifugal force, in which method the mineral melt is sup¬ plied onto a spinning wheel provided with at least one controllable magnetic bearing, or a corresponding spinn¬ ing wheel group, from which it is thrown off in the form of fibres or fibre embryos which are drawn into fibres using a gas jet, characterized in that the fibre gener¬ ation is controlled by causing vibrations in the spinning wheel in a controllable manner.
2. A method as claimed in patent claim 1, characterized in that radial vibrations are caused in the spinning wheel by controlling the magnetic bearings of the spin¬ ning wheel.
3. A method as claimed in patent claim 2, characterized in that radial vibrations are caused in the spinning wheel, the vibrations being directed in relation to flow direction of the melt.
4. A method as claimed in patent claim 2 - 3, character- ized in that radial vibrations are caused in the spinning wheel by adjusting the distance between the centre of mass and the rotation centre of the spinning wheel.
5. A method as claimed in patent claim 2 - 4, character- ized in that in the spinning wheel is caused through the magnetic bearing a radial vibration whose frequency is decisively higher than the rotation vibration frequency.
6. A method as claimed in any of the patent claims 1 - 5 characterized in that an axial vibration is caused in the spinning wheel.
EP19920900947 1990-12-07 1991-12-09 A method of producing fibres from mineral melt with the aid of centrifugal force Withdrawn EP0560869A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI906046A FI906046A (en) 1990-12-07 1990-12-07 SPINNHJULSENHET FOER FIBRERING AV MINERALSMAELTA MED HJAELP AV CENTRIFUGALKRAFTEN.
FI906046 1990-12-07

Publications (1)

Publication Number Publication Date
EP0560869A1 true EP0560869A1 (en) 1993-09-22

Family

ID=8531542

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920900947 Withdrawn EP0560869A1 (en) 1990-12-07 1991-12-09 A method of producing fibres from mineral melt with the aid of centrifugal force

Country Status (3)

Country Link
EP (1) EP0560869A1 (en)
FI (1) FI906046A (en)
WO (1) WO1992010435A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI121597B (en) 2007-04-20 2011-01-31 Paroc Oy Ab Method and apparatus for optimizing the function of a fibrous device forming mineral fiber and a program product
FI126895B (en) 2008-10-17 2017-07-31 Paroc Group Oy Method and arrangement for optimizing the production process of mineral fibers

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU83788A1 (en) * 1981-11-26 1983-09-01 Arbed SYSTEM FOR REGULATING THE MARKET OF A MINERAL FIBER THREADING SYSTEM

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9210435A1 *

Also Published As

Publication number Publication date
FI906046A (en) 1992-06-08
FI906046A0 (en) 1990-12-07
WO1992010435A1 (en) 1992-06-25

Similar Documents

Publication Publication Date Title
Shafai et al. Magnetic bearing control systems and adaptive forced balancing
KR100328205B1 (en) Fiber Optic Manufacturing Method
EP0560869A1 (en) A method of producing fibres from mineral melt with the aid of centrifugal force
CA2207573C (en) Method and apparatus for producing mineral wool
AU610163B2 (en) Fibrillation device for the manufacture of mineral wool
US5760511A (en) Magnetic bearing controller
US5401290A (en) Apparatus for VAD with a vibration detector to eliminate natural vibrations
US6056441A (en) Tire track roughened orifice compensated hydrostatic bearing
Tsao et al. Adaptive synchronization control of the magnetically suspended rotor system
US6079261A (en) Method and arrangement for levelling out tension variation of an optical fibre
JP3675903B2 (en) Optical fiber drawing method and apparatus
JPH0751903A (en) Main spindle device of machine tool
EP0810184B1 (en) Method of making optical fiber using a plasma torch fiber-drawing furnace
Lei et al. Sensor-based inspection of the formation accuracy in ultra-precision grinding (UPG) of aspheric surface considering the chatter vibration
EP2148842B1 (en) Method for optimising the operation of a fiberising apparatus which forms mineral fibre and a software product
RU97111799A (en) METHOD FOR MANUFACTURING ARTIFICIAL GLASS-like FIBROUS PRODUCTS
JPS61167304A (en) Control circuit for magnetic levitation travelling apparatus
SU1151371A1 (en) Boring method
CA2205298A1 (en) Manufacture of vitreous fibre products
WO1999029032A1 (en) Method for removing torque vibrations in an ac motor controlled by a frequency converter
Woolley Air bearings and drive systems in single-point diamond tool machine tools
Liu et al. A Precise Measure Method for the Unbalancing Vector of Spindle in Ultra-precision Diamond Turning
Bischof Dynamics and control of magnetically levitated high-speed rigid rotor to produce n-waved orbits
SU1707496A1 (en) Method and device for stabilization of shaft rotation
SU1703257A1 (en) Method of machining by rotary tool

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19930617

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK FR GB IT LI NL SE

RIN1 Information on inventor provided before grant (corrected)

Inventor name: ASTRAND, ERIK AXEL

Inventor name: HOIKKA, TIMO OLAVI

17Q First examination report despatched

Effective date: 19950221

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Withdrawal date: 19960717