US3575656A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for measuring pressure in vacuum interrupters
Assignee: ABB Inc USA
•
Filing: 1968-08-30
•
Granted: 1971-04-20
•
Expires: 1988-08-30
Abstract
Abstract Method and apparatus for measuring pressure in vacuum interrupters in which electrical connection to the metallic shield provided within the interrupter is not available. Transverse electrostatic and electromagnetic fields are generated within the interior of the vacuum interrupter so as to cause stray electrons within the interior space of the vacuum interrupter to travel in cycloidal or elliptical paths. The tortuous route assumed by the electrons greatly enhances the propability of an ionizing collision The pressure measurements are taken by measuring the number of positive ions collected at the negative electrode and comparing the measurement to a calibration chart on which pressure versus current has been plotted. The measurements may be taken by measuring the time required to charge a capacitor whose charging rate is determined by the vacuum interrupter resistance which is the unknown quantity being measured.
Inventors
- 👤 Ward W Watrous Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:28
CPC Classifications
H; H01; H01H; H01H33/00; H01H33/60; H01H33/66; H01H33/668; H01J; H01J41/00; H01J41/02; H01J41/06
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
292 words
A method for obtaining pressure measurements of the confined space within vacuum interrupters and the like having an evacuated envelope, a metallic vapor-condensing shield wholly contained within said evacuated envelope, and first and second electrical contacts positioned within the confined space of said envelope and said shield and surrounded by said shield comprising the steps of: developing an electrostatic field between said shield and said first and second contacts and between said first and second contacts by externally applying a unidirectional voltage across said electrical contacts while maintaining said shield electrically insulated from said contacts so that said shield is maintained at a potential substantially intermediate the potentials at each of said contacts whereby the electrostatic field lines between said first and second contacts are in the axial direction, the electrostatic field between said shield and said first contact are in a direction transverse to the axial direction and the electrostatic field lines between said shield and said second contact are in a direction transverse to the axial direction and opposite in direction to the field lines between said first contact and said shield; generating a magnetic field within the region of said shield and said first and second contacts by magnet means positioned external to said envelope so that said electrostatic and magnetic fields are simultaneously present and are aligned with their field patterns being substantially transverse to one another; measuring the ion current flowing between the two electrical contacts by externally coupling measuring means between said contacts so that said current flow can be determined as a result of ionizing collisions caused by stray electrons acted upon by the transversely aligned electrostatic and magnetic fields; determining the pressure within the confined space of said vacuum envelope from said current reading.
Claim 2
Independent Claim
292 words
A method for obtaining pressure measurements of the confined space within vacuum interrupters and the like having an evacuated envelope, a metallic vapor-condensing shield wholly contained within said evacuated envelope, and first and second electrical contacts positioned within the confined space of said envelope and said shield and surrounded by said shield comprising the steps of: developing an electrostatic field between said shield and said first and second contacts and between said first and second contacts by externally applying a unidirectional voltage across said electrical contacts while maintaining said shield electrically insulated from said contacts so that said shield is maintained at a potential substantially intermediate the potentials at each of said contacts whereby the electrostatic field lines between said first and second contacts are in the axial direction, the electrostatic field between said shield and said first contact are in a direction transverse to the axial direction and the electrostatic field lines between said shield and said second contact are in a direction transverse to the axial direction and opposite in direction to the field lines between said first contact and said shield; generating a magnetic field within the region of said shield and said first and second contacts by magnet means positioned external to said envelope so that said electrostatic and magnetic fields are simultaneously present and are aligned with their field patterns being substantially transverse to one another; measuring the ion current flowing between the two electrical contacts by externally coupling measuring means between said contacts so that said current flow can be determined as a result of ionizing collisions caused by stray electrons acted upon by the transversely aligned electrostatic and magnetic fields; determining the pressure within the confined space of said vacuum envelope from said current reading.
Claim 3
Dependent Claim
31 words
The method of claim 1 wherein the step of providing an electrostatic field is further comprised of applying a high voltage unidirectional source between the electrical contacts of the vacuum interrupter.
Claim 4
Dependent Claim
43 words
The method of claim 2 wherein the step of applying a high voltage unidirectional souRce between the electrical contacts of the vacuum interrupter is further comprised of the step maintaining the electrical contacts to substantially the fully opened position throughout the measurement operation.
Claim 5
Dependent Claim
41 words
The method of claim 1, wherein the step of generating a magnetic field is further comprised of aligning the magnetic field so that its magnetic field pattern is substantially in the axial direction within the confined space of said evacuated envelope.
Claim 6
Dependent Claim
61 words
The method of claim 1 wherein the step of determining the pressure measurement is further comprised of determining the pressure measurement from the current reading obtained by means of the relationship between current and pressure given by I bpn Where b A constant depending on the gauge construction n A constant (usually of the order of 1.1) p pressure I current.
Claim 7
Dependent Claim
200 words
Apparatus for determining the pressure within vacuum apparatus wherein the vacuum apparatus is comprised of a pair of electrical contacts movable between an engaged and a disengaged position, said contacts being disposed within the confined space of a vacuum envelope and surrounded by a metallic vapor-condensing shield wholly contained within said envelope and electrically insulated from said contacts, said apparatus being comprised of: a high voltage source being externally and electrically coupled between said electrical contacts which are maintained in substantially the fully opened position so that said vapor-condensing shield operates at a floating potential level which is substantially intermediate the potential levels of said contacts; magnetic field generating means positioned in close proximity to said vacuum apparatus so as to generate a magnetic field within the confined space of said evacuated envelope wherein the magnetic field pattern and electrostatic field pattern developed by said high voltage source are aligned substantially transverse to one another; means coupled in series with said high voltage source between said electrical contacts for measuring the ionizing current flowing between said contacts as a result of ionizing collisions produced by stray electrons within said envelope when acted upon by said cross-connected electrostatic and magnetic fields.
Claim 8
Dependent Claim
200 words
Apparatus for determining the pressure within vacuum apparatus wherein the vacuum apparatus is comprised of a pair of electrical contacts movable between an engaged and a disengaged position, said contacts being disposed within the confined space of a vacuum envelope and surrounded by a metallic vapor-condensing shield wholly contained within said envelope and electrically insulated from said contacts, said apparatus being comprised of: a high voltage source being externally and electrically coupled between said electrical contacts which are maintained in substantially the fully opened position so that said vapor-condensing shield operates at a floating potential level which is substantially intermediate the potential levels of said contacts; magnetic field generating means positioned in close proximity to said vacuum apparatus so as to generate a magnetic field within the confined space of said evacuated envelope wherein the magnetic field pattern and electrostatic field pattern developed by said high voltage source are aligned substantially transverse to one another; means coupled in series with said high voltage source between said electrical contacts for measuring the ionizing current flowing between said contacts as a result of ionizing collisions produced by stray electrons within said envelope when acted upon by said cross-connected electrostatic and magnetic fields.
Claim 9
Dependent Claim
53 words
The apparatus of claim 6 wherein said magnetic field generating means is comprised of a substantially annular-shaped permanent magnet surrounding the vacuum envelope so as to generate a magnetic field within the confined space of the vacuum envelope whose field lines are substantially in alignment with the longitudinal axes of said electrical contacts.
Claim 10
Dependent Claim
54 words
The apparatus of claim 7 wherein said magnetic field generating means is comprised of a substantially cylindrical shaped electrical coil surrounding the vacuum envelope so as to generate a magnetic field within the confined space of the vacuum envelope whose field lines are substantially in alignment with the longitudinal axes of said electrical contacts.
Claim 11
Dependent Claim
100 words
The apparatus of claim 6 wherein said measuring means is comprised of capacitor means connected to said vacuum apparatus being charged at a rate determined by the resistance of said vacuum apparatus; a normally open discharge path coupled across said capacitor means including means for closing said discharge path when said capacitor means reaches a first predetermined threshold voltage and for reopening said discharge path when said capacitor means discharges to a second predetermined threshold level; means for counting the number of charge-discharge cycles experienced by said capacitor means for determining the resistance value of the vacuum interrupter under test.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |