摘要:
According to a known vertical drawing method for producing a cylindrical glass body, the cylinder longitudinal axis of the glass cylinder is adjusted by hand in relation to the longitudinal axis of a heating tube. The aim of the invention is to optimize the stability of said glass body. Said aim is achieved, whereby adjustment comprises the steps of detecting a value for a first radial x-y position of the cylinder longitudinal axis (16) of the glass cylinder (4) in a first horizontal detection plane (E1), drawing the glass cylinder (4), placed in the first x-y position, to form a test glass strand (10), measuring an actual state of a radial circular, or annular dimension of the test glass strand, determining a deviation between the actual state and a set state of said circular, or annular dimension with regard to the size and position thereof, while considering the position of the glass cylinder (4) in relation to the inner wall of the heating tube (1) during drawing, calculating a corrected x-y position of the cylinder longitudinal axis (16) by means of a correction factor (K), the value and position of the deviation, arranging the glass cylinder (4) into the heating tube (1), so that the cylinder longitudinal axis (16) extends at least in the first horizontal detection plane (E1) in the x-y position and drawing the glass cylinder (4), arranged in the corrected x-y position, to form another test glass strand (10).
摘要:
According to a known vertical drawing method for producing a cylindrical glass body, the cylinder longitudinal axis of the glass cylinder is adjusted by hand in relation to the longitudinal axis of a heating tube. The aim of the invention is to optimise the stability of said glass body. Said aim is achieved, whereby adjustment comprises the steps of detecting a value for a first radial x-y position of the cylinder longitudinal axis (16) of the glass cylinder (4) in a first horizontal detection plane (E1), drawing the glass cylinder (4), placed in the first x-y position, to form a test glass strand (10), measuring an actual state of a radial circular, or annular dimension of the test glass strand, determining a deviation between the actual state and a set state of said circular, or annular dimension with regard to the size and position thereof, whilst considering the position of the glass cylinder (4) in relation to the inner wall of the heating tube (1) during drawing, calculating a corrected x-y position of the cylinder longitudinal axis (16) by means of a correction factor (K), the value and position of the deviation, arranging the glass cylinder (4) into the heating tube (1), so that the cylinder longitudinal axis (16) extends at least in the first horizontal detection plane (E1) in the x-y position and drawing the glass cylinder (4), arranged in the corrected x-y position, to form another test glass strand (10).
摘要:
In a known method for the manufacture of a tube made of a vitreous material, especially of quartz glass, a hollow cylindrical semifinished product made of a vitreous material is carried essentially vertically to a heating zone, wherein it is heated and drawn off downwards—without the use of tools—to the tube by forming a transitional area from semifinished product to tube, while diameter and wall thickness of the tube are continuously measured, and the tube's measured geometrical data being used to generate a control signal with the aid of which a pressure difference is regulated between pressure P1 in the interior space of the semifinished product, the transitional area and the tube, as well as pressure P2 in the heating chamber which is regulated in the heating zone at least in the transitional area from semifinished product to tube and its adjacent tube area. This method is to be developed further so as to enable the processing of a broader spectrum of hollow cylindrical semifinished products to tubes with the desired inside and outside dimensions. This task is solved according to the invention such that for the manufacture of tubes with the ratio of their outside diameter (DRa) to their inside diameter (DRi) being greater than the ratio of the outside diameter (DHa) to the inside diameter (DHi) of the semifinished product—pressure P1 in the inside space of the semifinished product, the transitional area and the tube being kept at a value which is smaller than the value of pressure P2 in the heating chamber, with pressure P1 being maintained by means of a suction (vacuum) pump.
摘要:
A method for using a temperature control loop in order to further develop process control during elongation of a cylindrical preform such that a component strand with high dimensional accuracy can be drawn even in the presence of temperature-effective defects during the elongation process: (a) the continuous measurement of a first temperature value, Ttop, at an upper measuring point on the surface of the cylindrical preform; (b) the continuous measurement of a second temperature value, Tbottom, at a lower measuring point; (c) calculation of a temperature distribution in the region between the measuring points Ttop and Tbottom, and determination of a modelled deformation temperature, Tmodel, using an algorithmic model taking with first and the second temperature values as model input parameters, and the modelled deformation temperature, Tmodel, as a regulating variable and the heating-zone temperature Toven as a manipulated variable for the temperature-control loop.
摘要:
In a known method for producing a tube of quartz glass by elongation, a hollow cylinder of quartz glass is continuously supplied to a heating zone, softened therein zone by zone, and a tube strand is drawn in the direction of a drawing axis out of the softened region by using a roll puller, the roll puller comprising a frame by which a plurality of puller rolls are fixed, which are rotatable around a rotation axis and which are distributed over the circumference of the tube strand and adjoining the tube strand with their cylindrical outer surface. Starting therefrom, to indicate a vertical drawing method in which a high draw ratio can also be accomplished with little constructional effort by using a take-off unit in the form of a roll puller and which simultaneously allows an optimization of the dimensional stability of the quartz glass tubes obtained, and which particularly avoids material losses caused by ovality and siding, the invention suggests that the frame of the roll puller s stationary, and the hollow cylinder and the tube strand are rotated about the drawing axis relative to one another, the relative rotation being set to a range between 0.01 and 5 revolutions per linear meter of drawn-off tube strand.
摘要:
The present invention refers to a drawing method for producing cylindrical components of quartz glass in that a quartz glass strand is drawn off in the direction of a drawing axis from a shaping zone of soft quartz glass mass and sections having a cutting length are separated from the quartz glass strand, and the cylindrical components are produced from the sections.
摘要:
In a known drawing method for producing cylinder-shaped components from quartz glass, a quartz glass strand (10) is drawn in the direction of a drawing axis (12) from a deformation region of a quartz glass mass (9) and pieces having a cutting length (S) are separated therefrom. The cylinder-shaped components are produced from the pieces. In order to provide a simple drawing method for producing quartz glass components, wherein the effects of geometric disruptions, in particular variations in diameter and material rejects, are reduced, the separation of the quartz glass strand (10) is carried out at a separating position (T), wherein the distance of the separating position from the deformation region (9) is set in a way such that a disruption of the quartz glass strand geometry created by the separation lies in an end region of the component to be produced or between two neighboring components during a subsequent separation.
摘要:
In a known method for producing a cylindrical glass body in a vertical drawing process, a glass blank is softened in a heating zone and drawn off as a glass strand by means of a draw-off device at a controlled drawing speed, the draw-off device comprising a first draw-off unit with rolling bodies rolling on the glass strand and being distributed around the circumference thereof, the rolling bodies being formed by a reference rolling body and at least one auxiliary rolling body, the drawing speed being controlled via the speed of the reference rolling body. Starting therefrom, in order to reduce damage to the surface of the glass strand caused by the draw-off device and to avoid deformations caused by existing bends of the glass strand, it is suggested according to the invention that a value for the torque of the reference rolling body (3) should be determined in dependence upon the weight of the drawn-off glass strand (5), and that the determined value should be used as a setpoint torque for setting the torque in the at least one auxiliary rolling body (4; 7; 8).
摘要:
In a known method for producing a cylindrical glass body in a vertical drawing process, a glass blank is softened in a heating zone and drawn off as a glass strand by means of a draw-off device at a controlled drawing speed, the draw-off device comprising a first draw-off unit with rolling bodies rolling on the glass strand and being distributed around the circumference thereof, the rolling bodies being formed by a reference rolling body and at least one auxiliary rolling body, the drawing speed being controlled via the speed of the reference rolling body. Starting therefrom, in order to reduce damage to the surface of the glass strand caused by the draw-off device and to avoid deformations caused by existing bends of the glass strand, it is suggested according to the invention that a value for the torque of the reference rolling body (3) should be determined in dependence upon the weight of the drawn-off glass strand (5), and that the determined value should be used as a setpoint torque for setting the torque in the at least one auxiliary rolling body (4; 7; 8).
摘要:
A known resistance furnace comprises a tubular heating element having a vertically oriented longitudinal axis, which comprises a shell surface defined by an upper side and a lower side and surrounding a furnace chamber, and which is connected to at least two supply terminals by means of which heating current is introduced at power supply points into the heating element. Starting from the above, in order to provide an electric resistance furnace, in particular a high-performance resistance furnace which is characterized by small manufacturing and maintenance efforts and by a high operational reliability, and which permits the reproducible adjustment of an axially and radially homogeneous temperature profile within the furnace, it is suggested according to the invention that the supply terminals should comprise a surrounding upper annular collar (7) in the region of the upper side (11) and a surrounding lower annular collar (8) in the region of the lower side (12).