Smoke detector apparatus and ionization chamber therefor

An ionization chamber for a combustion product indicating apparatus, said ionization chamber comprising:

• an insulated mounting board;
• a wire mesh collector positioned on said mounting board and providing a first electrode, said wire mesh collector and said board defining the walls of said ionization chamber;
• an electrically conductive retainer plate within said chamber and adjacent to said mounting board;
• a radioactive source within said chamber and spaced from said wire mesh collector for emitting alpha particles therein;
• an insulated source mount within said chamber and adjacent to said retainer plate, said radioactive source being mounted thereon;
• and
• a tuning screw extending through said retainer plate and said source mount so that a portion of said tuning screw providing a second electrode is within said chamber adjacent to said radioactive source.

An ionization chamber for a combustion product indicating apparatus, said ionization chamber comprising:

• an apertured collector at least partially forming the walls of said chamber and providing a first electrode;
• electrically nonconductive mounting means forming the remainder of the walls of said chamber and having said apertured collector fastened thereto;
• a second electrode having at least a portion within said chamber formed by said apertured collector and said mounting means with said second electrode being spaced from said apertured collector;
• and
• a radioactive source mounted on said mounting means and spaced from said apertured collector with said source emitting alpha particles into said chamber.

An ionization chamber for a combustion product indicating apparatus, said ionization chamber comprising:

• an insulated mounting board;
• an apertured collector positioned on said mounting board and providing a first electrode, said apertured collector and said board defining the walls of said ionization chamber;
• an electrically conductive retainer plate within said chamber and adjacent to said mounting board;
• a radioactive source within said chamber and spaced from said apertured collector for emitting alpha particles therein;
• an insulated source mount within said chamber and adjacent to said retainer plate, said radioactive source being mounted thereon;
• and
• a tuning screw extending through said retainer plate and said source mount so that a portion of said tuning screw providing a second electrode is within said chamber adjacent to said radioactive source.