Chemistry: physical processes – Physical processes – Crystallization
Patent
1975-08-26
1976-11-02
Scovronek, Joseph
Chemistry: physical processes
Physical processes
Crystallization
73 23, 317246, 317249R, 317258, 340237R, G01N 2700, G01N 3100, G08B 2100, H01G 500
Patent
active
039894630
ABSTRACT:
An air pollutant and/or fire combustion sensing apparatus includes a pair of sensing electrodes separated by a free space to define a capacitance unit. At least one of the electrodes includes a corrosion-resistant, conductive material which interacts with air borne products to alter the permittivity and/or charge transfer characteristic of the unit. The material is in the form of a highly corrosion-resistant metal selected from a metal or metal alloy including at least one of the metals selected from the Group VIII, periods 4, 5, and 6 of the periodic table, particularly rhodium and stainless steel. Carbon and copper respond to produce a detectible output. An amplifying and alarm circuit is connected to the capacitance unit, and responds to either an increase or a decrease in the capacitance as a result of the interaction with the sensing electrode material. The circuit includes a thermally stabilized field effect transistor as a buffer input amplifier connected in differential configuration to produce a high input impedance and a high gain. The transistor is connected to a high gain DC operational amplifier having a feedback compensation network to compensate for thermal and low frequency drift change. A constant current source provides the bias supply to the input amplifier to improve common mode rejection and the thermal stability. A pair of programmable unijunction transistors are connected to the output of the operational amplifier and to the input of an alarm device to detect either an increase or a decrease at the amplifier output which may arise as a result of the decreased or increased capacitance characteristics of the air borne material.
REFERENCES:
patent: 2972570 (1961-02-01), Haas et al.
patent: 3255389 (1966-06-01), Salomon et al.
patent: 3483451 (1969-12-01), Klerer
patent: 3495142 (1970-02-01), Herrgen et al.
patent: 3754219 (1973-08-01), Klein
patent: 3798516 (1974-03-01), Short
Klein Carl F.
Thoma Paul E.
Weber Gerald E.
Johnson Controls Inc.
Scovronek Joseph
LandOfFree
Sensing element and detection system employing such element for does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sensing element and detection system employing such element for , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sensing element and detection system employing such element for will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1156749