US4587463A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Absorbance monitor
Assignee: Teledyne Isco Inc
•
Filing: 1983-09-22
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Granted: 1986-05-06
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Expires: 2003-09-22
Abstract
Abstract To provide a reliable start for cadmium and zinc lamps and reduce baseline noise in an absorbance monitor, voltage pulses are applied to the primary of a transformer followed by shutoff of the primary current which discharges the energy stored in the magnetizing inductance of the transformer as three thousand volt peaks in its secondary in a series of timed steps. At the end of the timed period, the system shuts down unless it has approached operating frequency. The frequency is controlled by the amount of current passing through a gas discharge lamp in circuit with the transformer secondary and the frequency controls the amplitude of the voltage spikes. After warm-up, blanking pulses prevent optical noise from electrical-path-change oscillations within the tube. In one embodiment, a constant current source controls the current and in another, an operating current and frequency are established by the transformer leakage inductance and lamp characteristics in the circuit.
Inventors
- 👤 Robert W. Allington
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:30
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/26; H05B41/28; H05B41/288; H05B41/292; H05B41/2921; H05B41/2925; H05B41/36; H05B41/38; Y; Y10; Y10S; Y10S315/00; Y10S315/07
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
295 words
Apparatus comprising: a lamp transformer; said lamp transformer having a primary and secondary winding; said lamp transformer having sufficiently high inductance and low loss to store energy capable of creating a pulse of at least 1,000 volts amplitude with a pulse width of at least 10 microseconds across a resistance of at least 20 kiloohms in the secondary of the lamp transformer from an average current flowing through the primary corresponding to an input power load of less than five times the normal operating power; means adapted to connect the secondary winding of said lamp transformer in circuit with a lamp; means for sensing current through said lamp; means for applying pulses at a comparatively low frequency to the primary of said transformer under the control of said means for sensing current; said means for applying pulses including means for open-circuiting said primary after a current pulse has been applied, whereby a high potential spike is applied across said lamp to cause it to start; means for increasing the frequency of said pulses as said current increases up to a first predetermined value during a first period of time; means for limiting said current to said first predetermined value; means for timing said first period of time until said current reaches said predetermined value; means for terminating said pulses when time is exceeded unless said current has reached a second predetermined value that may be less or the same as the said first predetermined value; means for applying short blanking pulses to interrupt said pulses applied to the primary of said transformer; and timing means for preventing the application of said blanking pulses for a second period of time for at least two seconds from the beginning of said application of pulses to said transformer.
Claim 2
Dependent Claim
295 words
Apparatus comprising: a lamp transformer; said lamp transformer having a primary and secondary winding; said lamp transformer having sufficiently high inductance and low loss to store energy capable of creating a pulse of at least 1,000 volts amplitude with a pulse width of at least 10 microseconds across a resistance of at least 20 kiloohms in the secondary of the lamp transformer from an average current flowing through the primary corresponding to an input power load of less than five times the normal operating power; means adapted to connect the secondary winding of said lamp transformer in circuit with a lamp; means for sensing current through said lamp; means for applying pulses at a comparatively low frequency to the primary of said transformer under the control of said means for sensing current; said means for applying pulses including means for open-circuiting said primary after a current pulse has been applied, whereby a high potential spike is applied across said lamp to cause it to start; means for increasing the frequency of said pulses as said current increases up to a first predetermined value during a first period of time; means for limiting said current to said first predetermined value; means for timing said first period of time until said current reaches said predetermined value; means for terminating said pulses when time is exceeded unless said current has reached a second predetermined value that may be less or the same as the said first predetermined value; means for applying short blanking pulses to interrupt said pulses applied to the primary of said transformer; and timing means for preventing the application of said blanking pulses for a second period of time for at least two seconds from the beginning of said application of pulses to said transformer.
Claim 3
Dependent Claim
149 words
Apparatus according to claim 1 in which said means for applying pulses includes: a switching circuit electrically connected to said transformer primary circuit; said switching circuit including means for causing current to flow in one direction through the primary circuit, abruptly stopping the flow of current in the said one direction and causing current to flow in the opposite direction from a source of current alternately, whereby said primary currents are abruptly stopped alternately first in one direction and then in the other direction to transmit high potential peaks from the inductive field to the secondary of said transformer; and said means for causing current to flow including means for causing the time of switching and the inductance of said primary winding to form said voltage peaks at an amplitude of at least one thousand volts before said lamp conducts at the frequency for low current through said lamp.
Claim 4
Dependent Claim
173 words
Apparatus according to claim 1 in which said means for applying pulses includes: a switching circuit electrically connected to said transformer primary circuit; said primary winding including a center tap and first and second end taps, whereby current may flow through the primary in either of two different directions; said switching circuit including means for causing current to flow in one direction through the primary circuit, abruptly stopping the flow of current in said one direction and causing current to flow in the opposite direction from a source of current alternately, whereby said primary currents are abruptly stopped alternately first in one direction and then in the other direction to transmit high potential peaks from the inductive field to the secondary of said transformer; and said means for causing current to flow including means for causing the time of switching and the inductance of said primary winding to form said voltage peaks at an amplitude of least one thousand volts before said lamp conducts at the frequency for low current through said lamp.
Claim 5
Dependent Claim
184 words
Apparatus according to claim 1 in which said means for applying pulses at a low frequency includes: a switching circuit electrically connected to said transformer primary circuit; said primary winding including a center tap and first and second end taps, whereby current may flow through the primary in either of two directions; said switching current including means for causing current to flow in the opposite direction from a source of current alternately, whereby said primary currents are abruptly stopped alternately first in one direction and then in the other direction to transmit high potential peaks from the inductive field to the secondary of said transformer; said means for causing current to flow including means for causing time of switching and the inductance of said primary winding to form said voltage peaks of an amplitude of least one thousand volts before said lamp conducts at the frequency for low current through said lamp; and timing means for preventing the application of said blanking pulses for a period of time of at least two seconds from the beginning of said application of pulses to said transformer.
Claim 6
Dependent Claim
184 words
Apparatus according to claim 2 in which said means for applying pulses at a comparatively low frequency includes: a switching circuit electrically connected to said transformer primary circuit; said switching circuit including means for causing current to flow in one direction through the primary circuit, abruptly stopping the flow of current in said one direction and causing current to flow in the opposite direction from a source of current alternately, whereby said primary currents are abruptly stopped alternately first in one direction and then in the other direction to transmit high potential peaks from the inductive field to the secondary of said transformer; said means for causing current to flow including means for causing the time of switching and the inductance of said primary winding to form said voltage peaks at an amplitude of at least one thousand volts before said lamp conducts at the frequency for low current through said lamp; and timing means for preventing the application of said blanking pulses for a period of time of at least two seconds from the beginning of said application of pulses to said transformer.
Claim 7
Dependent Claim
184 words
Apparatus comprising: a lamp transformer; said lamp transformer having a primary and a secondary winding; means adapted to connect the secondary winding of said lamp transformer in circuit with a gas discharge lamp; means for applying pulses to the primary of said transformer; said means for applying pulses including means for stopping current flow to said primary after a current pulse has been applied, whereby a high potential spike is applied across said lamp to cause it to start; means for increasing the frequency of said pulses as said current increases up to a first predetermined value during a period of time; means for limiting said current at said first predetermined value; and said lamp transformer having sufficiently high inductance and low loss to store energy capable of creating a pulse of at least 1,000 volts amplitude with a pulse width of at least 10 microseconds across a resistance of at least 20 kiloohms in the secondary of the lamp transformer from an average current flowing through the primary corresponding to an input power load of less than five times the normal operating power.
Claim 8
Dependent Claim
184 words
Apparatus comprising: a lamp transformer; said lamp transformer having a primary and a secondary winding; means adapted to connect the secondary winding of said lamp transformer in circuit with a gas discharge lamp; means for applying pulses to the primary of said transformer; said means for applying pulses including means for stopping current flow to said primary after a current pulse has been applied, whereby a high potential spike is applied across said lamp to cause it to start; means for increasing the frequency of said pulses as said current increases up to a first predetermined value during a period of time; means for limiting said current at said first predetermined value; and said lamp transformer having sufficiently high inductance and low loss to store energy capable of creating a pulse of at least 1,000 volts amplitude with a pulse width of at least 10 microseconds across a resistance of at least 20 kiloohms in the secondary of the lamp transformer from an average current flowing through the primary corresponding to an input power load of less than five times the normal operating power.
Claim 9
Dependent Claim
45 words
Apparatus according to claim 6 further including: means for sensing lamp current; and said means for applying pulses to the primary of said transformer including means for applying pulses to the primary of said transformer under the control of said means for sensing lamp current.
Claim 10
Dependent Claim
21 words
Apparatus according to claim 7 in which said lamp has an initial igniting voltage at least three times its running voltage.
Claim 11
Dependent Claim
55 words
Apparatus according to claim 6 further including: means for timing said period of time until said current reaches a second predetermined value which may be the same or less than the said first predetermined value; and means for terminating said pulses when said time is exceeded unless said current has reached said second predetermined value.
Claim 12
Dependent Claim
42 words
Apparatus according to claim 6 further including means for blanking the said pulses to said primary of said transformer for a period of time at least equal to the time otherwise required for the consecutive occurrence of two of the said pulses.
Claim 13
Dependent Claim
70 words
Apparatus according to claim 6 further including: means for blanking the said pulses to said primary of said transformer for a period of time at least equal to the time otherwise required for the consecutive occurrence of two of the said pulses; and timing means for preventing the blanking for a period of time of at least two seconds from the beginning of said application of pulses to said transformer.
Claim 14
Dependent Claim
204 words
Apparatus according to claim 10 in which said means for applying pulses to the primary of said transformer includes: a switching circuit electrically connected to said primary winding; said primary winding including a center tap and first and second end taps, whereby current may flow through the primary in either of two directions; said switching circuit including means for causing current to flow in one direction while cutting off current flow in the other direction, stopping current flow from the transformer in the one direction, and causing current to flow in the opposite direction from a source of current alternately, whereby the energy in an inductive field of the transformer is discharged to a secondary circuit alternately first in one direction and then in the other direction, thus transmitting high potential peaks from the inductive field to the secondary of said transformer; said means for causing current to flow including means for causing the time of switching and the inductance of said primary winding to form said voltage peaks having an amplitude of at least one thousand volts before said lamp conducts; and means for preventing self-rectification of said lamp after said lamp is ignited in response to the operating current through said lamp.
Claim 15
Dependent Claim
203 words
Apparatus according to claim 11 in which said means for applying pulses to the primary of said transducer includes: a switching circuit electrically connected to said primary winding; said primary winding including a center tap and first and second end taps, whereby current may flow through the primary in either of two directions; said switching circuit including means for causing current to flow in one direction while cutting off current flow in the other direction, stopping current flow from the transformer in the one direction, and causing current to flow in the opposite direction from a source of current alternately, whereby the energy in an inductive field of the transformer is discharged to a secondary circuit alternately first in one direction and then in the other direction, thus transmitting high potential peaks from the inductive field to the secondary of said transformer; said means for causing current to flow including means for causing the time of switching and the inductance of said primary winding to form said voltage peaks of an amplitude at least one thousand volts before said lamp conducts; and means for preventing self-rectification of said lamp after said lamp is ignited in response to the operating current through said lamp.
Claim 16
Dependent Claim
64 words
Apparatus according to claim 6 further including: means for blanking the said pulses to said primary of said transformer for a period of time longer than twice the normal operating pulse duration; and timing means for preventing the application of said blanking pulses for a period of time of at least two seconds from the beginning of said application of pulses to said transformer.
Claim 17
Dependent Claim
196 words
Apparatus according to claim 14 in which said means for applying pulses includes: a switching circuit electrically connected to said primary winding; said primary winding including a center tap and first and second end taps, whereby current may flow through the primary in either of two directions; said switching circuit including means for causing current to flow in one direction while cutting off current flow in the other direction, stopping current flow from the transformer in the one direction, and causing current to flow in the opposite direction from a source of current alternately, whereby the energy in an inductive field of the transformer is discharged to a secondary circuit alternately first in one direction and then in the other direction, thus transmitting high potential peaks from the inductive field to the secondary of said transformer; said means for causing current to flow including means for causing the time of switching and the inductance of said primary winding to form voltage peaks having an amplitude at least one thousand volts before said lamp conducts; and means for preventing self-rectification of said lamp after said lamp is ignited in response to the operating current through said lamp.
Claim 18
Dependent Claim
201 words
Apparatus according to claim 6 in which said means for applying pulses includes: a switching circuit electrically connected to said primary winding; said primary winding including a center tap and first and second end taps, whereby current may flow through the primary in either of two directions; said switching circuit including means for causing current to flow in one direction while cutting off current flow in the other direction, stopping current flow from the transformer in the one direction, and causing current to flow in the opposite direction from a source of current alternately, whereby the energy in an inductive field of the transformer is discharged to a secondary circuit alternately first in one direction and then in the other direction, thus transmitting high potential peaks from the inductive field to the secondary of said transformer; means for causing current to flow including means for causing the time of switching and the inductance of said primary winding to form voltage peaks having an amplitude at least one thousand volts before said lamp conducts; and means for preventing high voltage peaks above the peak voltage of said lamp after said lamp is ignited in response to the operating current through said lamp.
Claim 19
Dependent Claim
174 words
Apparatus according to claim 6 in which said means for applying pulses includes: a switching circuit electrically connected to said primary winding; said primary winding including a center tap and first and second end taps, whereby current may flow through the primary in either of two directions; said switching circuit including means for causing current to flow in one direction while cutting off current flow in the other direction, stopping current flow from the transformer in one direction, and causing current to flow in the opposite direction from a source of current alternately, whereby the energy in an inductive field of the transformer is discharged to a secondary circuit alternately first in one direction and then in the other direction, thus transmitting high potential peaks from the inductive field to the secondary of said transformer; and said means for causing current to flow including means for causing the time of switching and the inductance of said primary winding to form voltage peaks having an amplitude at least one thousand volts before said lamp conducts.
Claim 20
Dependent Claim
118 words
Apparatus according to claim 16 further including: means for controlling the current at a first predetermined level; said means for controlling including a triggering circuit means for sensing current and effecting stopping of current flow from a source of current alternately, each time the magnitude of the said current increases to the triggering level of the said triggering circuit, whereby said lamp inherently starts at a low frequency under the influence of large voltage spikes from the said transformer and, as the lamp starts, the frequency inherently rises to whatever is required so that the series impedance presented by the leakage inductance of the said transformer causes the current to regulate itself to the said first predetermined value.
Claim 21
Dependent Claim
46 words
Apparatus according to claim 7 in which said transformer primary includes a center tap and said switching means alternately blocks current through a first half while permitting it through the second half and blocks current through the second half while permitting it through the first half.
Claim 22
Dependent Claim
83 words
Apparatus according to claim 19 in which said switching means includes: first and second power switches having first and second control elements and each being connected to a different end of said transformer winding; and bistable means converted to said first and second control elements for alternately driving one of said first and second power switches into conduction while driving the other into nonconducting and driving the other of said first and second power switches into conduction while driving the other into nonconduction.
Claim 23
Dependent Claim
31 words
Apparatus according to claim 18 further including means for periodically inhibiting said bistable means for short periods of time starting at least two seconds after pulses are applied to said transformer.
Claim 24
Dependent Claim
56 words
Apparatus according to claim 18 further including: means for timing a period of time until said current reaches a second predetermined value which may be the same or less than the said first predetermined value; and means for determining said period of pulses when said time is exceeded unless said current has reached said predetermined value.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-05 | 1989-11-04 | 1990-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-05 | 1993-11-04 | 1994-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-05 | 1997-11-04 | 1998-05-06 | $7700.00 | Window Closed / Lapsed |