Electrochemical gas sensor with wraparound reference electrode
First Claim
1. An electrochemical sensor for gas detection comprising an impervious, nonconductive sensor body having a first cavity extending therein from a first end thereof, said first cavity having a plurality of sensor elements stacked therein including a sensing electrode positioned at an inner end of said first cavity and against said sensor body, a first mat positioned against said sensing electrode, a reference electrode positioned against said first mat, a second mat positioned against said reference electrode, and a counter electrode positioned against said second mat, said sensor also including a support means within said first cavity for holding said electrodes and mats in contact with each other and at the inner end of said first cavity, contact means for making electrical contact with said sensing, counter and reference electrodes, cap means for covering an open end of said first cavity and holding said support means therein, said support means and cap means defining an electrolyte chamber therebetween, with said electrolyte chamber being at least partially filled with a liquid electrolyte, said sensor having gas passage means through said body for permitting gas to reach said sensing electrode, and electrolyte flow means for directing said liquid electrolyte to said mats and electrodes, with said reference electrode having a central portion disposed between said sensing and counter electrodes and having at least one extension attached thereto at an outer edge of said central portion and extending around said counter electrode and said support means and into contact with the electrolyte in said electrolyte chamber.
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Abstract
An electrochemical sensor for detecting gas includes stacked reference, counter and sensing electrodes within a body and having a quantity of a liquid electrolyte in an electrolyte chamber therein. A support is provided for holding the electrodes and mats in contact with each other and at an inner end of a cavity within the sensor. A gas passage, such as a diffusion limiter, is provided through the sensor body and permits gas to reach the sensing electrode. The reference electrode is formed in a wraparound structure, with the reference electrode provided with a plurality of integral extensions which extend around the support and the counter electrode and into contact with the liquid electrolyte, thereby providing a large reference electrode fitted into a small body.
208 Citations
20 Claims
- 1. An electrochemical sensor for gas detection comprising an impervious, nonconductive sensor body having a first cavity extending therein from a first end thereof, said first cavity having a plurality of sensor elements stacked therein including a sensing electrode positioned at an inner end of said first cavity and against said sensor body, a first mat positioned against said sensing electrode, a reference electrode positioned against said first mat, a second mat positioned against said reference electrode, and a counter electrode positioned against said second mat, said sensor also including a support means within said first cavity for holding said electrodes and mats in contact with each other and at the inner end of said first cavity, contact means for making electrical contact with said sensing, counter and reference electrodes, cap means for covering an open end of said first cavity and holding said support means therein, said support means and cap means defining an electrolyte chamber therebetween, with said electrolyte chamber being at least partially filled with a liquid electrolyte, said sensor having gas passage means through said body for permitting gas to reach said sensing electrode, and electrolyte flow means for directing said liquid electrolyte to said mats and electrodes, with said reference electrode having a central portion disposed between said sensing and counter electrodes and having at least one extension attached thereto at an outer edge of said central portion and extending around said counter electrode and said support means and into contact with the electrolyte in said electrolyte chamber.
- 16. An electrochemical sensor for gas detection comprising an impervious, nonconductive sensor body having a first cavity extending therein from a first end thereof, said first cavity having a plurality of sensor elements stacked therein including a sensing electrode positioned at an inner end of said first cavity and against said sensor body, a first mat positioned against said sensing electrode, a reference electrode positioned against said first mat, a second mat positioned against said reference electrode, and a counter electrode positioned against said second mat, said sensor including a cup-shaped plunger within said first cavity for holding said electrodes and mats in contact with each other and at the inner end of said first cavity, said sensor also including a contact means for making electrical contact with said sensing, counter and reference electrodes, cap means for covering an open end of said first cavity and holding said support means therein, with said plunger having a closed end oriented toward the stacked electrodes and mats and having an open end oriented toward said cap means, said plunger and cap means defining an electrolyte chamber therebetween, with said electrolyte chamber being at least partially filled with a liquid electrolyte, said sensor having gas passage means through said body for permitting gas to reach said sensing electrode, and electrolyte flow means for directing said liquid electrolyte to said mats and electrodes, with said reference electrode having a central portion disposed between said sensing and counter electrodes and having at least one extension attached thereto at an outer edge of said central portion and extending around said counter electrode and said plunger and into contact with the electrolyte in said electrolyte chamber, and with said first mat having a central portion disposed between said reference and sensing electrodes and at least one projection attached thereto at an outer edge of said central portion, with said first mat projection extending about and contacting the reference electrode projection and extending into contact with the electrolyte in said electrolyte chamber.
- 18. An electrochemical sensor for gas detection comprising an impervious, nonconductive sensor body having a first cavity extending therein from a first end thereof, said first cavity having a plurality of sensor elements stacked therein including a sensing electrode positioned at an inner end of said first cavity and against said sensor body, a first mat positioned against said sensing electrode, a reference electrode positioned against said first mat, a second mat positioned against said reference electrode, and a counter electrode positioned against said second mat, said sensor including a cup-shaped plunger within said first cavity for holding said electrodes and mats in contact with each other and at the inner end of said first cavity, said sensor also including a contact means for making electrical contact with said sensing, counter and reference electrodes, cap means for covering an open end of said first cavity and holding said support means therein, with said plunger having a closed end oriented toward the stacked electrodes and mats and having an open end oriented toward said cap means, said plunger and cap means defining an electrolyte chamber therebetween, with said electrolyte chamber being at least partially filled with a liquid electrolyte, said sensor having gas passage means through said body for permitting gas to reach said sensing electrode, and electrolyte flow means for directing said liquid electrolyte to said mats and electrodes, with said reference electrode having a central portion disposed between said sensing and counter electrodes and having a plurality of extensions attached thereto at an outer edge of said central portion and extending around said counter electrode and said plunger and into contact with the electrolyte in said electrolyte chamber.
Specification