GB1297296A – – Google Patents
GB1297296A – – Google Patents
Info
Publication number
GB1297296A
GB1297296A
GB1297296DA
GB1297296A
GB 1297296 A
GB1297296 A
GB 1297296A
GB 1297296D A
GB1297296D A
GB 1297296DA
GB 1297296 A
GB1297296 A
GB 1297296A
Authority
GB
United Kingdom
Prior art keywords
mirror
bridge
photo
current
condensate
Prior art date
1969-12-18
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1969-12-18
Filing date
1970-11-27
Publication date
1972-11-22
1970-11-27
Application filed
filed
Critical
1972-11-22
Publication of GB1297296A
publication
Critical
patent/GB1297296A/en
Status
Expired
legal-status
Critical
Current
Links
Espacenet
Global Dossier
Discuss
Classifications
G—PHYSICS
G01—MEASURING; TESTING
G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
G01N25/00—Investigating or analyzing materials by the use of thermal means
G01N25/56—Investigating or analyzing materials by the use of thermal means by investigating moisture content
G01N25/66—Investigating or analyzing materials by the use of thermal means by investigating moisture content by investigating dew-point
G01N25/68—Investigating or analyzing materials by the use of thermal means by investigating moisture content by investigating dew-point by varying the temperature of a condensing surface
Abstract
1297296 Dewpoint hygrometer EG & G Inc 27 Nov 1970 [18 Dec 1969] 56425/70 Heading, G1A In a dewpoint hygrometer employing two photo-sensitive resistors within a bridge circuit and and a mirror whose temperature is maintained at dewpoint by a servo-loop operating a cooling device attached to the mirror, the effects of the build up of contaminants on the mirror is neutralized by including a variable resistor in the bridge, the resistor being continuously or periodically adjusted to rebalance the bridge. In one embodiment, Fig. 3 light from a source 32 is directed onto a mirror 12 and the reflected and scattered light is received by photo-sensitive resistors 64 and 66 respectively. The thickness of the condensate on the mirror will determine the relative proportions of scattered and reflected light. The photo-sensitive resistors 64 and 66 are connected as shown, in a bridge 120 the output from which is fed via a pre-amplifier 126 and a power control amplifier 128 to a current regulator 46 which controls the cooling current from a current supply 44 for a thermoelectric cooler 14. The bridge is initially balanced for a particular thickness of condensate by means of variable resistors 124 and 82, and the arrangement is such that the mirror will then be maintained at the dewpoint temperature of the gas flowing past its reflective surface. The temperature of the mirror is monitored by means of a thermocouple 48, an amplifier 50 and a meter 52. The build up of contaminants on the mirror’s reflective surface is neutralized by employing an alternating current generator 130 so that an oscillatory current is added to the cooling current. This results in small fluctuations in the mirror’s mean temperature and a corresponding fluctuation in the thickness of the condensate which in turn influences the resistances of photo-sensitive resistors 64 and 66. The amplitude of the resulting alternating current is measured by a detector 136 with the aid of a turned amplifier 134. The detector’s output drives a meter 138 and a lamp 140 which irradiates a further photo-resistor 122 connected in the bridge as shown. Thus any unbalancing of the bridge by contaminants causes a change in the temperature of the mirror, and, thus a change in the thickness of the condensate is sensed as a change in amplitude by detector 136 whose output will change accordingly and thereby change the resistance of photo-resistor 122. In a similar embodiment Fig. 4 (not shown), the A.C. current generator 30 is omitted, and instead the gain feedback system, provided by preamplifier 128, is increased to the point where slight instability occurs and the system becomes self oscillatory. / In a further embodiment, Fig. 2, which periodically adjusts the bridge circuit to neutralize the effect of contaminants, a motor B2 is employed to control a timing switch 51 energizing a first relay K1 which controls contacts K1B interrupting the cooling current servo-loop and allows the mirror to increase in temperature and evaporate the condensate. A second relay K2 is connected to an electronic switch 92 which is responsive to a predetermined error signal from the bridge 60 greater than a predetermined value. The second relay controls the circuit of a balance B1 motor which drives a potentiometer 68 in the bridge circuit 60. Thus the potentiometer is adjusted till the bridge is balanced and the error signal is reduced sufficiently to de-activate relay K2.
GB1297296D
1969-12-18
1970-11-27
Expired
GB1297296A
(en)
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
US88622069A
1969-12-18
1969-12-18
Publications (1)
Publication Number
Publication Date
GB1297296A
true
GB1297296A
(en)
1972-11-22
Family
ID=25388642
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB1297296D
Expired
GB1297296A
(en)
1969-12-18
1970-11-27
Country Status (2)
Country
Link
US
(1)
US3623356A
(en)
GB
(1)
GB1297296A
(en)
Cited By (1)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
CN113358696A
(en)
*
2021-08-10
2021-09-07
北京亿华通科技股份有限公司
Dew point temperature detection device and method for fuel cell
Families Citing this family (39)
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Publication number
Priority date
Publication date
Assignee
Title
US3930398A
(en)
*
1972-07-17
1976-01-06
Tatyana Abramovna Levina
Device for continuous temperature measurement of dew point of flue gases
US4035644A
(en)
*
1975-07-01
1977-07-12
Ciemochowski Michael F
Atmospheric condition detecting and indicating apparatus and method
GB1554879A
(en)
*
1975-09-29
1979-10-31
Univ Sydney
Phase transition detector
US4216669A
(en)
*
1978-10-06
1980-08-12
General Eastern Instruments Corporation
Contaminant error reduction system for dew point hygrometers
US4240284A
(en)
*
1979-08-03
1980-12-23
Sereg
Method and apparatus for determining the temperature of the condensation point of a substance
US4335597A
(en)
*
1980-03-28
1982-06-22
Eg & G, Inc.
Dew point hygrometer with two cooled reflective surfaces
US4345455A
(en)
*
1980-03-28
1982-08-24
Eg&G, Inc.
Dew point hygrometer with continuous balancing system
US4629333A
(en)
*
1984-10-19
1986-12-16
Eg&G, Inc.
Chilled mirror hygrometer with performance monitoring
US4701052A
(en)
*
1985-05-24
1987-10-20
Schoen Jr Oscar W
Dew point hygrometer
GB8514584D0
(en)
*
1985-06-10
1985-07-10
Shell Int Research
Measuring dew-point of gas stream
CA1280910C
(en)
*
1988-11-02
1991-03-05
Paul Siska
Dew point analyzer
CA1316704C
(en)
*
1988-02-10
1993-04-27
Charles Yam-Chuen Tsang
Method and apparatus for monitoring cloud point
US5028143A
(en)
*
1989-10-31
1991-07-02
Phillips David E
Humidity dew point sensor
US5482371A
(en)
*
1991-04-18
1996-01-09
Osaka Sanso Kogyo Ltd.
Method and apparatus for measuring the dew point and/or frost point of a gas having low water content
EP0535248B1
(en)
*
1991-04-18
1999-06-30
Osaka Sanso Kogyo Limited
Method of measuring the dew point and/or frost point of a gas having low water content and apparatus therefor
US5470154A
(en)
*
1991-04-18
1995-11-28
Osaka Sanso Kogyo Ltd.
Method of cleaning the reflector mirror in an optical dew point meter and an optical dew point meter equipped with a cleaning device
US5299867A
(en)
*
1992-06-30
1994-04-05
Buck Arden L
Low moisture cryogenic hygrometer
US5507175A
(en)
*
1994-10-21
1996-04-16
Protimeter, Inc.
Cycling chilled mirror dewpoint hygrometer including a sapphire optical mirror
US6926439B2
(en)
1998-10-30
2005-08-09
Optiguide Ltd.
Dew point hygrometers and dew sensors
IL126826A0
(en)
1998-10-30
1999-08-17
Optiguide Ltd
Optical hygrometers
DE102005027087A1
(en)
*
2005-06-11
2006-12-14
Leopold Kostal Gmbh & Co. Kg
Fog sensor, for motor vehicle, has light receiver detecting light that is reflected from inner side of windscreen, where light receiver is arranged behind of black impression of windscreen
JP5643602B2
(en)
*
2010-10-27
2014-12-17
アズビル株式会社
Mirror surface cooling type sensor
CA2807615C
(en)
2012-03-08
2020-06-30
Simplehuman, Llc
Vanity mirror
JP5890247B2
(en)
*
2012-05-10
2016-03-22
アズビル株式会社
Mirror surface dew point meter
JP5890246B2
(en)
*
2012-05-10
2016-03-22
アズビル株式会社
Mirror surface dew point meter
JP6078365B2
(en)
*
2013-02-08
2017-02-08
アズビル株式会社
Mirror surface dew point meter
CA2861170A1
(en)
*
2013-09-04
2015-03-04
Simplehuman, Llc
Anti-fogging mirrors and methods
US10076176B2
(en)
2015-03-06
2018-09-18
Simplehuman, Llc
Vanity mirror comprising light sources and methods of manufacture thereof
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2015-03-06
2017-05-02
Simplehuman, Llc
Mirror
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2017-03-17
2018-05-01
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2017-03-17
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2017-12-28
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2018-02-14
2021-06-08
Simplehuman, Llc
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2018-03-08
2019-04-23
Simplehuman, Llc
Vanity mirror
CA3037704A1
(en)
2018-03-22
2019-09-22
Simplehuman, Llc
Voice-activated vanity mirror
USD874161S1
(en)
2018-09-07
2020-02-04
Simplehuman, Llc
Vanity mirror
USD925928S1
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2019-03-01
2021-07-27
Simplehuman, Llc
Vanity mirror
EP3931615A1
(en)
2019-03-01
2022-01-05
Simplehuman LLC
Vanity mirror
USD927863S1
(en)
2019-05-02
2021-08-17
Simplehuman, Llc
Vanity mirror cover
1969
1969-12-18
US
US886220A
patent/US3623356A/en
not_active
Expired – Lifetime
1970
1970-11-27
GB
GB1297296D
patent/GB1297296A/en
not_active
Expired
Cited By (1)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
CN113358696A
(en)
*
2021-08-10
2021-09-07
北京亿华通科技股份有限公司
Dew point temperature detection device and method for fuel cell
Also Published As
Publication number
Publication date
US3623356A
(en)
1971-11-30
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Legal Events
Date
Code
Title
Description
1973-04-04
PS
Patent sealed [section 19, patents act 1949]
1989-07-19
PCNP
Patent ceased through non-payment of renewal fee
1989-08-16
PCNP
Patent ceased through non-payment of renewal fee
Free format text:
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