Abstract: A MEA 6 having a proton conductive membrane is sandwiched by metal plates 14, 15 and they are further sandwiched by heat pressable films 20, 21. An opening 24 and an opening 18 are formed in the heat pressable film 20 and the metal plate 14, respectively so that an electrode 10 is used as the sensing electrode and exposed to atmosphere to be measured. Openings 25, 19 are formed in the heat pressable film 21 and metal plate 15, respectively so that an electrode 11 is used as the counter electrode, and water vapor is supplied to the electrode from a water pack.

Abstract: A proton conductor gas sensor whose durability at high temperature is enhanced by using gel not converted to sol even at high temperature in a water reservoir. Fine particles of silica are gelled by adding water thereto and agitating the mixture under shear force. The thus obtained gel (34) is placed in a water reservoir of proton conductor gas sensor (2) and fed through steam introduction port (30) to MEA (10).

Abstract: A proton conductor gas sensor whose durability at high temperature is enhanced by using gel not converted to sol even at high temperature in a water reservoir. Fine particles of silica are gelled by adding water thereto and agitating the mixture under shear force. The thus obtained gel (34) is placed in a water reservoir of proton conductor gas sensor (2) and fed through steam introduction port (30) to MEA (10).

Abstract: A MEA 6 having a proton conductive membrane is sandwiched by metal plates 14, 15 and they are further sandwiched by heat pressable films 20, 21. An opening 24 and an opening 18 are formed in the heat pressable film 20 and the metal plate 14, respectively so that an electrode 10 is used as the sensing electrode and exposed to atmosphere to be measured. Openings 25, 19 are formed in the heat pressable film 21 and metal plate 15, respectively so that an electrode 11 is used as the counter electrode, and water vapor is supplied to the electrode from a water pack.

Abstract: A solid electrolyte gas-sensing device comprising a solid electrolyte layer (a) and a reference electrode layer (b) and a working electrode layer (c) with the solid electrolyte layer (a) being an intermediate layer therebetween, said working electrode layer (c) having a mixture layer (d) in the interface between said solid electrolyte layer (a) and said working electrode layer (c), the mixture layer (d) being formed from a metal salt which shows dissociation equilibrium with a gas to be measured and an electron-conducting substance, the mixture layer (d) containing 0.5 to 14% by volume of the electron-conducting substance.

Abstract: A solid electrolyte gas sensor and a method for the measurement of a concentration of a gas to be detected in a gas mixture. The sensor has (A) a screen for controlling a permeation rate of the gas, which comprises (a1) a first solid electrolytic membrane selectively permeable to ions derived from a specific gas, and (a2) a plurality of first porous conductors being present on both front and reverse surfaces of the first solid electrolytic membrane and electrically connected with each other so as to give a potential required for oxidation and reduction of the gas, and (B) a detection portion for detecting a permeation amount of ions derived from the gas, which comprises (b1) a second solid electrolytic membrane, (b2) a plurality of second porous conductors, and (b3) means of electrically measuring an amount of ions derived from the gas which permeates the second solid electrolytic membrane.