Abstract: An outer peripheral edge part of the air-fuel mixture permeable member is connected to a portion away outward by a predetermined distance from an inner peripheral edge of the burner frame. Between the burner frame and the air-fuel mixture permeable member a clearance reaching the inner peripheral edge of the burner frame is secured at a position inward of the outer peripheral part of the air-fuel mixture permeable member. Preferably, a bent edge part formed on an inner peripheral edge of the burner frame, in a manner to be bent toward the air-fuel mixture permeable member. The amount of the air-fuel mixture to flow into the clearance is limited to a smaller amount.

Abstract: A heat exchanger prevents cracking in heat transfer plates while avoiding lowering heat-exchange efficiency. Heat transfer plates are arranged with a space between them, and a hollow pipe extends through the plates. A high-temperature gas flows through the space to exchange heat with a liquid in the hollow pipe. The heat transfer plates are elongated in the direction in which parts of the hollow pipe are aligned and can thus have thermal expansion accumulating in the elongation direction. The heat transfer plates each include a thermal expansion absorber between an edge of the heat transfer plate receiving inflow of the high-temperature gas and an inter-pipe portion between adjacent parts of the hollow pipe to absorb thermal expansion of the heat transfer plate. A selected one or more of the inter-pipe portions, rather than all, include the thermal expansion absorber.

Abstract: The air-fuel mixture permeable member is disposed to overlap that surface of the burner frame which lies opposite to the burner body. The fixing frame is disposed so as to be fixed to the inner peripheral portion of the enclosing frame part of the burner frame by pinching the air-fuel mixture permeable member between the inner peripheral portion and the fixing frame. The air-fuel mixture permeable member has an extended part protruding outward beyond the fixing frame so as to cover by this extended part an outer peripheral portion of the enclosing frame part.

Abstract: An outer peripheral edge part of the air-fuel mixture permeable member is connected to a portion away outward by a predetermined distance from an inner peripheral edge of the burner frame. Between the burner frame and the air-fuel mixture permeable member a clearance reaching the inner peripheral edge of the burner frame is secured at a position inward of the outer peripheral part of the air-fuel mixture permeable member. Preferably, a bent edge part formed on an inner peripheral edge of the burner frame, in a manner to be bent toward the air-fuel mixture permeable member. The amount of the air-fuel mixture to flow into the clearance is limited to a smaller amount.

Abstract: A heat exchanger prevents cracking in heat transfer plates while avoiding lowering heat-exchange efficiency. Heat transfer plates are arranged with a space between them, and a hollow pipe extends through the plates. A high-temperature gas flows through the space to exchange heat with a liquid in the hollow pipe. The heat transfer plates are elongated in the direction in which parts of the hollow pipe are aligned and can thus have thermal expansion accumulating in the elongation direction. The heat transfer plates each include a thermal expansion absorber between an edge of the heat transfer plate receiving inflow of the high-temperature gas and an inter-pipe portion between adjacent parts of the hollow pipe to absorb thermal expansion of the heat transfer plate. A selected one or more of the inter-pipe portions, rather than all, include the thermal expansion absorber.

Abstract: A flame rod (1) including: a rod portion (11) made of a metal material containing aluminum; and a protective cover layer (21) containing a cover material having high conductivity and high heat resistance, wherein the protective cover layer (21) covers a surface of an insertion portion (11A) of the flame rod (11), and the protective cover layer (11) has a thickness of 0.002 mm or more and less than 0.1 mm.

Abstract: A combustion apparatus having: an upstream-side air supply chamber and a downstream-side mixing passage, both being respectively interposed between a fan and a burner; and a zero governor which is interposed in a gas supply passage and which adjusts a secondary gas pressure to a pressure equivalent to an internal pressure in the air supply chamber, thereby enabling to maximize a turndown ratio to the extent possible. The combustion apparatus has: first and second, totally two, mixing passages; a first gas outlet which is in communication with a narrowed part of the first mixing passage; a second gas outlet which is in communication with a narrowed part of the second mixing passage; a first air valve which varies an opening degree of an air inlet of the first mixing passage; a second air valve which varies an opening degree of an air inlet of the second mixing passage; and a gas valve.

Abstract: A flame rod (1) including: a rod portion (11) made of a metal material containing aluminum; and a protective cover layer (21) containing a cover material having high conductivity and high heat resistance, wherein the protective cover layer (21) covers a surface of an insertion portion (11A) of the flame rod (11), and the protective cover layer (11) has a thickness of 0.002 mm or more and less than 0.1 mm.

Abstract: A combustion apparatus having: an upstream-side air supply chamber and a downstream-side mixing passage, both being respectively interposed between a fan and a burner; and a zero governor which is interposed in a gas supply passage and which adjusts a secondary gas pressure to a pressure equivalent to an internal pressure in the air supply chamber, thereby enabling to maximize a turndown ratio to the extent possible. The combustion apparatus has: first and second, totally two, mixing passages; a first gas outlet which is in communication with a narrowed part of the first mixing passage; a second gas outlet which is in communication with a narrowed part of the second mixing passage; a first air valve which varies an opening degree of an air inlet of the first mixing passage; a second air valve which varies an opening degree of an air inlet of the second mixing passage; and a gas valve.

Abstract: A flat burner has at an upper end thereof a rectangular flame port portion which has a straightening member with a plurality of straightening plates laterally disposed in parallel with one another. The straightening member has contact portions in which the straightening plates are brought into contact with one another at a plurality of longitudinal positions to thereby longitudinally segregate the flame port passages that are defined by each of the straightening plates. Out of the contact portions of the laterally inside straightening plates defining the laterally center-side flame port passages of the flame port portion, at least lower half of the contact portions that are positioned at least in predetermined longitudinal portions is formed into an inverse triangle as seen in the lateral direction.

Abstract: A flat burner has a mixing tube portion with an inlet port of a cross section elongated in a vertical direction and a throat portion lying adjacent to a back of the inlet port and having a cross section smaller than that of the inlet port. A distribution chamber portion introduces a mixture of a fuel gas ejected from a gas nozzle disposed to face the inlet port and primary air flowing from the inlet port. The throat portion is formed at a position in which a sectional center thereof is offset in one of the upward and downward directions relative to a sectional center of the inlet port. The gas nozzle is disposed such that an axis of the nozzle hole of the gas nozzle passes through a vertical position that is offset from the sectional center of the throat portion toward the sectional center of the inlet port.

Abstract: A flat burner has at an upper end thereof a rectangular flame port portion which has a straightening member with a plurality of straightening plates laterally disposed in parallel with one another. The straightening member has contact portions in which the straightening plates are brought into contact with one another at a plurality of longitudinal positions to thereby longitudinally segregate the flame port passages that are defined by each of the straightening plates. Out of the contact portions of the laterally inside straightening plates defining the laterally center-side flame port passages of the flame port portion, at least lower half of the contact portions that are positioned at least in predetermined longitudinal portions is formed into an inverse triangle as seen in the lateral direction.

Abstract: A combustion plate for use in a totally aerated combustion burner has a ceramic plate body with a multiplicity of flame holes formed therein for ejecting a premixed gas. The plate body is provided, in a lattice shape, with non-flame-hole portions having no flame holes therein. Each of such regions of the plate body as are enclosed by the non-flame-hole portions constitutes a collective flame-hole portion having formed therein a plurality of flame holes. It is so arranged that flame lifting can be effectively prevented in the flame holes on the periphery of the collective flame-hole portions. Along each of such sides of the non-flame-hole portions as are adjacent to each of the collective flame-hole portions, outside flame holes are formed at a predetermined spacing therebetween in a longitudinal direction of the non-flame-hole portions. This predetermined spacing is greater than a spacing, in the longitudinal direction of the non-flame-hole portion.

Abstract: A combustion apparatus has a burner, a combustion box containing therein a heat exchanger, an exhaust passage in fluid communication with the combustion box, a fan for supplying the burner with combustion air, and a predetermined length of air suction duct in fluid communication with a suction opening formed in a fan casing. The air suction duct has: on a downstream end thereof, an outlet cylindrical portion which is smaller in diameter than a diameter of the suction opening in the fan casing and which lies opposite to the suction opening; and a flange portion which overhangs radially outward from a perimeter of the air suction duct adjacent to the outlet cylindrical portion into contact with that peripheral portion of the fan casing which forms the suction opening. The flange portion is provided with an auxiliary suction opening in fluid communication with a space surrounding the outlet cylindrical portion.

Abstract: A rich-lean burner with a lean flame port, a blind clearance, and a rich flame port has: a burner main body with a pair of burner-main-body side plates on both lateral sides thereof; a burner cap with a burner-cap side plate covering the burner main body from at least one lateral outside thereof; and a straightening member with straightening plates to divide the lean flame port into laterally disposed zones. Upper ends of the burner-main-body side plates are below upper ends of the burner-cap side plate and of the straightening plates. The straightening member has a partition plate which is located laterally outside an outer straightening plate contiguous to the blind clearance and which extends upward beyond the burner-main-body side plates. The blind clearance is defined between the partition plate and the outer straightening plate, and the rich flame port is defined between the partition plate and the burner-cap side plate.

Abstract: A totally aerated combustion burner having a combustion plate with a multiplicity of flame holes includes a distribution chamber, a mixing chamber, and an air supply chamber. The mixing chamber has a front surface with a plurality of nozzle holes disposed in parallel with, and at a lateral distance from, one another so that a fuel gas to be ejected from the nozzle holes and the primary air from the air supply chamber get mixed in the mixing chamber. A wall plate is disposed upright on a bottom surface of the mixing chamber in a manner to lie opposite to the front surface of the mixing chamber while leaving a ventilation clearance to the front surface. An air inlet is formed in such a portion at the bottom surface of the mixing chamber as to face the ventilation clearance.

Abstract: A combustion plate for use in a totally aerated combustion burner has a ceramic plate body with a multiplicity of flame holes formed therein for ejecting a premixed gas. The plate body is provided, in a lattice shape, with non-flame-hole portions having no flame holes therein. Each of such regions of the plate body as are enclosed by the non-flame-hole portions constitutes a collective flame-hole portion having formed therein a plurality of flame holes. It is so arranged that flame lifting can be effectively prevented in the flame holes on the periphery of the collective flame-hole portions. Along each of such sides of the non-flame-hole portions as are adjacent to each of the collective flame-hole portions, outside flame holes are formed at a predetermined spacing therebetween in a longitudinal direction of the non-flame-hole portions. This predetermined spacing is greater than a spacing, in the longitudinal direction of the non-flame-hole portion.

Abstract: A totally aerated combustion burner having a combustion plate with a multiplicity of flame holes includes a distribution chamber, a mixing chamber, and an air supply chamber. The mixing chamber has a front surface with a plurality of nozzle holes disposed in parallel with, and at a lateral distance from, one another so that a fuel gas to be ejected from the nozzle holes and the primary air from the air supply chamber get mixed in the mixing chamber. A wall plate is disposed upright on a bottom surface of the mixing chamber in a manner to lie opposite to the front surface of the mixing chamber while leaving a ventilation clearance to the front surface. An air inlet is formed in such a portion at the bottom surface of the mixing chamber as to face the ventilation clearance.