US3768313A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of determining the risk of explosion of a preferably gaseous medium and apparatus for carrying out this method
Assignee: INDUSTRILABORATORIET AB
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Filing: 1971-11-30
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Granted: 1973-10-30
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Expires: 1991-11-30
Abstract
Abstract The risk of explosion of a preferably gaseous medium is determined by measuring a parameter, which is determinative of the inflammability of the medium, by means of a probe, which comprises an ignition chamber and an ignition initiator in said chamber. A successively varied amount of energy is sequentially supplied to the ignition initiator, until the amount of energy, which is operatively therein, has reached such a level that the medium in the ignition chamber only just ignites. The actuation level, at which the medium in the ignition chamber actuated by the ignition initiator ignites, constitutes a measure of said parameter of the medium and is determined by adequate, preferably electrical means.
Inventors
- 👤 S Johansson
- 👤 L Johnsson
- 👤 K Strid
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:56
CPC Classifications
G; G01; G01N; G01N25/00; G01N25/50; G01N25/54
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
147 words
A method of determining the risk of explosion of a preferably gaseous medium by means of a probe, which comprises an ignition chamber, which is provided with apertures, a fine-mesh gauze covering said apertures having a mesh smaller than the quenching distance of said medium and comprising the step of measuring a parameter, which is determinative of the inflammability of the medium, particularly the ignition energy or the ignition temperature, including supplying a successively varied amount of energy to an explosion initiator, which is arranged in said ignition chamber, until the amount of energy, which is operative in the explosion initiator, has reached such a level that the medium in the ignition chamber only just ignites, and measuring the activation level, at which the medium in the ignition chamber actuated by the explosion initiator ignites, said activation level constituting a measure of said parameter of the medium.
Claim 2
Independent Claim
147 words
A method of determining the risk of explosion of a preferably gaseous medium by means of a probe, which comprises an ignition chamber, which is provided with apertures, a fine-mesh gauze covering said apertures having a mesh smaller than the quenching distance of said medium and comprising the step of measuring a parameter, which is determinative of the inflammability of the medium, particularly the ignition energy or the ignition temperature, including supplying a successively varied amount of energy to an explosion initiator, which is arranged in said ignition chamber, until the amount of energy, which is operative in the explosion initiator, has reached such a level that the medium in the ignition chamber only just ignites, and measuring the activation level, at which the medium in the ignition chamber actuated by the explosion initiator ignites, said activation level constituting a measure of said parameter of the medium.
Claim 3
Dependent Claim
140 words
Apparatus for determining the risk of explosion of a preferably gaseous medium by determining its imflammability, comprising in combination a probe, which comprises an ignition chamber, which is provided with apertures a fine-mesh gauze covering said apertures having a mesh smaller than the quenching distance of said medium, an explosion initiator which is arranged in said ignition chamber, means connected to said probe for supplying a successively varied amount of energy to the explosion initiator, until the amount of energy, which is operative in the explosion initiator, has reached such a level that the medium in the ignition chamber only just ignites, and electrical means associated with said probe for measuring the activation level, at which the medium in the ignition chamber actuated by the explosion initiator ignites, said activation level constituting a measure of the inflammability of the medium.
Claim 4
Dependent Claim
140 words
Apparatus for determining the risk of explosion of a preferably gaseous medium by determining its imflammability, comprising in combination a probe, which comprises an ignition chamber, which is provided with apertures a fine-mesh gauze covering said apertures having a mesh smaller than the quenching distance of said medium, an explosion initiator which is arranged in said ignition chamber, means connected to said probe for supplying a successively varied amount of energy to the explosion initiator, until the amount of energy, which is operative in the explosion initiator, has reached such a level that the medium in the ignition chamber only just ignites, and electrical means associated with said probe for measuring the activation level, at which the medium in the ignition chamber actuated by the explosion initiator ignites, said activation level constituting a measure of the inflammability of the medium.
Claim 5
Dependent Claim
75 words
Apparatus according to claim 2, characterized in that the apparatus is designed for the measurement of the ignition energy of the medium, said ignition initiator being comprised of a spark gap and said means for supplying energy to the ignition initiator being comprised of means for generating at least one electric impulse adapted to be applied to the spark gap, said impulse generating means being connectable to the ignition initiator by means of coaxial cables.
Claim 6
Dependent Claim
47 words
Apparatus according to claim 3, characterized in that the means for measuring the ignition energy is an oscilloscope for measuring the energy contents of the impulse, said oscilloscope being Connected to one of the members of the group formed by said impulse generator and said spark gap.
Claim 7
Dependent Claim
51 words
Apparatus according to claim 2, characterized in that the apparatus is designed for the measurement of the ignition temperature of the medium, and in that said ignition initiator is a heating body and the means for supplying energy to the ignition initiator is comprised of means for heating said heating body.
Claim 8
Dependent Claim
15 words
Apparatus according to claim 5, characterized in that said heating body is an incandescent body.
Claim 9
Dependent Claim
14 words
Apparatus according to claim 5, characterized in that said heating body is electrically heated.
Claim 10
Dependent Claim
85 words
Apparatus according to claim 7, characterized in that said heating body constitutes one arm of a Wheatstone bridge having an adjustable voltage source for heating the heating body connected across one of its diagonals and said means for measuring the activation level connected across its other diagonal, said measuring means being comprised of an instrument for measuring the unbalance voltage of the bridge, which is due to the alteration of the resistance of the heating body on acount of its heating through the energy supply.
Claim 11
Dependent Claim
15 words
Apparatus according to claim 7, characterized in that said heating body is a thermo-electric couple.
Claim 12
Dependent Claim
66 words
Apparatus according to claim 9, characterized by the provision of a high frequency voltage source, which is connected to said heating body through reactive means, such as a pair of capacitors, for heating said body, and a voltmeter, which is connected to said thermo-electric couple for determining the voltage thereover, which occurs at the heating thereof, said voltmeter constituting said means for measuring said actuation level.
Claim 13
Dependent Claim
16 words
Apparatus according to claim 10, characterized in that said voltmeter is graduated in units of temperature.
Claim 14
Dependent Claim
78 words
Apparatus according to claom 7, characterized by the provision of an adjustable voltage source for heating said heating body, a gate circuit for governing the output voltage of said voltage source and having two inputs, a transducer comprised in the probe and connected to one of the inputs of said gate circuit, and a function generator, which is connected to the other one of the inputs of said gate circuit for supplying a repetitive ramp function voltage thereto.
Claim 15
Dependent Claim
78 words
Apparatus according to claom 7, characterized by the provision of an adjustable voltage source for heating said heating body, a gate circuit for governing the output voltage of said voltage source and having two inputs, a transducer comprised in the probe and connected to one of the inputs of said gate circuit, and a function generator, which is connected to the other one of the inputs of said gate circuit for supplying a repetitive ramp function voltage thereto.
Claim 16
Dependent Claim
17 words
Apparatus according to claim 12, characterized in that the ramp function voltage is of the sawtooth type.
Claim 17
Dependent Claim
17 words
Apparatus according to claim 12, characterized in that the ramp function voltage has an adjustable repetition frequency.
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) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |