Agitating – By vibration – Of platform or mixing chamber supported by vibrator
Patent
1998-07-24
2000-11-21
Soohoo, Tony G.
Agitating
By vibration
Of platform or mixing chamber supported by vibrator
366128, 164261, B22D 1104
Patent
active
061492922
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention pertains to an oscillating table, in particular for use in a continuous casting machine, comprising a movable part, coupled via an eccentric to a driving mechanism for introducing an upward and downward oscillation motion.
In a continuous casting machine, used i.a. in steel production, the oscillation table is used to impart to the casting mould an upward and downward oscillation motion, either according to a defined radius or, less frequently, along a vertical direction in order to prevent the cast steel from remaining stuck to the water-cooled copper wall of the mould.
In the presently in use oscillating tables, the applied oscillation frequency is dependent upon the casting speed. The amplitude is fixed but is generally adaptable by exchanging eccentrics.
In the upward motion of the casting mould, there is always a relative speed difference between slab, billet or bloom being formed and the casting mould.
In the downward motion of the casting mould, the speed of the casting mould is initially less than, subsequently equal and thereafter greater than, the speed of the slab, billet or bloom. Upon the end of the descending motion, the speed of the casting mould is again equal to and thereafter less than the speed of the slab.
The period during which the speed of the casting mould in the downward motion is greater than the speed of the billet is referred to as the "negative strip".
The usual driving mechanisms for oscillating tables use linear electric motors driving eccentric shafts via reduction gearboxes and driving shafts. This results in a sinusoidal movement which is not satisfactory because the time during which the speed of the slab is nearly equal to the speed of the mould during the downward movement of the mould and causes the cast steel to stuck to the wall of the mould is too long.
SUMMARY OF THE INVENTION
It is a goal of the invention to provide an oscillating table of the type mentioned hereabove, whereby the drawbacks of existing oscillating tables are avoided. To this end, the oscillating table according to the invention is characterised in that, the driving mechanism comprises driving means for driving the eccentric with a non-uniform angular speed. In this way the facility is obtained to operate any lifting and descending motion of the casting mould. By maximizing the negative strip, i.e. by raising the downward speed of the casting mould to a considerably higher value than that of the upward speed, the period during which the cast steel strikes onto the wall of the mould because of the too small difference in speed is not long enough for the cast steel to stuck to the wall of the mould.
An embodiment of the oscillating table according to the invention is characterised in that the driving means comprises a hydraulic motor provided with a control system. By way of a hydraulic motor a non-uniform angular speed of the outgoing driving shaft can be easily obtained by controlling the pressure of the supplied hydraulic oil.
An advantageous embodiment is characterised in that the control system comprises a hydraulic servo or proportional valve and an electronic controller for controlling the servo or valve.
In practice the oscillating table is nearly always driven via more than one eccentric. A further embodiment of the oscillating table according to the invention is characterised in that the driving mechanism comprises a further eccentric driven by a further hydraulic motor and means for synchronising the two hydraulic motors.
The motors need to have perfect synchronization. To this end still a further embodiment is characterised in that the synchronising means comprises measurement means for indicating the exact position of the motors, which measurement means are coupled to the control system. By interaction between the electronic controller for controlling the hydraulic servo or proportional valves and the position measurements of the motors, perfect synchronization is obtained.
A preferred embodiment is characterised in that, the synchron
REFERENCES:
patent: 3407670 (1968-10-01), Venanzetti
patent: 3724819 (1973-04-01), Varnum et al.
patent: 3866480 (1975-02-01), Elliston
patent: 4151982 (1979-05-01), Herz
patent: 4202634 (1980-05-01), Kraft et al.
patent: 4262549 (1981-04-01), Schwellenbach
patent: 4766771 (1988-08-01), Bailey et al.
patent: 4860816 (1989-08-01), Bond
Abstract of Japanese Patent Publication 57-12549.
Sidmar N.V.
Soohoo Tony G.
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