Abstract: A fine bubble generator may include an inlet into which gas-dissolved water in which gas is dissolved flows, an outlet out of which the gas-dissolved water flows; and a fine bubble generation portion disposed between the inlet and the outlet. The fine bubble generation portion may include a venturi portion including a diameter-reducing flow path and a diameter-increasing flow path, wherein a flow path diameter of the diameter-reducing flow path reduces from upstream to downstream, and the flow path diameter of the diameter-increasing flow path increases from upstream to downstream, a discharging flow path configured to discharge the gas-dissolved water, which flowed out of the venturi portion, out of the fine bubble generation portion; and a recirculation flow path connecting a midstream of the outflow path and the venturi portion.

Abstract: A fine bubble generator may include an inlet; an outlet; a first fine bubble generation portion; and a second fine bubble generation portion. The first fine bubble generation portion includes: a diameter-reducing flow path and a diameter-increasing flow path. The second fine bubble generation portion includes: a first swirling flow generation portion; and a second swirling flow generation portion. The first swirling flow generation portion includes: a first outer peripheral portion; and a plurality of first vanes disposed configured to generate a first swirling flow flowing in a first swirling direction with respect to a center axis of the second fine bubble generation portion. The second swirling flow generation portion includes: a second outer peripheral portion; and a plurality of second vanes configured to generate a second swirling flow flowing in a second swirling direction opposite to the first swirling direction with respect to the center axis.

Abstract: A fine bubble generator may include an inlet, an outlet, a first fine bubble generation portion including a first flow path, and a second fine bubble generation portion including a second flow path. The first flow path may include a diameter-reducing flow path and a diameter-increasing flow path. The second flow path may include a guide flow path and a collision flow path disposed downstream of the guide flow path. A first bearing and a first impeller rotatably attached to the first bearing may be disposed on the collision flow path. The first impeller may include a disc disposed at a position at which the gas-dissolved water collides with the disc; a first rotation shaft disposed on a downstream surface of the disc and rotatably attached to the first bearing; and one or more first vanes disposed on an upstream surface of the disc.

Abstract: A heat source device including a sheet-metal burner body (30), a fan casing (40) connected to the burner body (30), an annular packing (90) connecting a burner-side connection end surface (340) with a fan-side connection end surface (410) in an airtight state, a sheet-metal connection part (80) disposed between the burner-side connection end surface (340) and the fan-side connection end surface (410), wherein the connection part has an opening (85) and a packing storage portion (84) storing the annular packing (90), wherein the opening (85) is provided in such a manner that an opening edge is positioned outside of those of an inlet port (35) and a blowout port (44) in a state where the connection part (80) is disposed between the burner-side connection end surface (340) and the fan-side connection end surface (410).

Abstract: A gas manifold allows each distribution chamber to be fed with fuel gas at an appropriate flow rate irrespective of an increase in the number of distribution chambers included in the gas manifold. A gas manifold distributes fuel gas flowing in through an inlet to a plurality of distribution chambers through a main channel. The main channel includes a flow guide that guides the fuel gas toward a maximum distribution chamber and reduces the fuel gas flowing into other distribution chambers. This allows fuel gas at a sufficient flow rate to be fed more easily to the maximum distribution chamber than to the other distribution chambers for a larger number of distribution chambers included in the gas manifold, allowing the plurality of distribution chambers to be fed with fuel gas at appropriate flow rates.

Abstract: In a water heater provided with an inlet pipe a downstream end of which is connected with an upstream end of a water heating channel of a heat exchanger for producing hot water, an outlet pipe an upstream end of which is connected with a downstream end of the water heating channel, and a bypass pipe branching at a part of the inlet pipe, which is positioned at an upstream-end part away from an upstream end, and is connected with a part of the outlet pipe, which is positioned at a more downstream part than at an upstream end, a connecting part of the bypass pipe with the outlet pipe and another connecting part of an inlet pipe and the upstream end of the water heating channel are arranged at a same height in a setting state of the water heater.

Abstract: A combustion chamber inside a combustion box has disposed therein a burner positioning frame having: a rear frame part positioned on a rear side of a burner-disposed portion; and a burner positioning frame having side frame part positioned on each laterally outside of the burner-disposed portion. The rear frame part has formed therein a laterally elongated drawn part which is dented rearward. The secondary air flowing from the distribution holes positioned in such a portion of the partition plate as is closer to the rear end of the partition plate is restrained by the drawn part from flowing upward from between the partition plate and a lower edge of the rear frame part through a clearance between the rear frame part and a rear plate part of the combustion box.

Abstract: An electrically operated gas flow regulating valve in which a needle valve body (2) is moved axially through a motion conversion mechanism (4) by the rotation of an electric motor (3). The motion conversion mechanism (4) includes: a guide tube (5) in which is formed axially elongated slits (51) with which cam pins (21) fixed to the needle valve (2) are slidably engaged; and a tubular cam body (6) having a spiral cam part with which the cam pins (21) are engages through elongated slits (51). In an arrangement in which one of the guide tube (5) and the cam body (6), e.g., the guide tube (5), is rotated by the electric motor (3), hysteresis is restrained from occurring. The cam part disposed in the cam body (6) is constituted by a spirally inclined sides (61) with which the cam pins (21) are brought into contact from axial one direction. A spring member (7) is disposed so as to urge the cam pins (21) in the other of the axial directions toward the spirally inclined sides (61).

Abstract: A premixing apparatus for mixing air with a fuel gas to supply a burner with an air-fuel mixture via a fan includes: a zero governor and a motor-driven type of variable throttle valve, both being disposed in a gas supply passage; and an excess air ratio detecting device for detecting an excess air ratio of the air-fuel mixture, thereby regulating an opening degree of the variable throttle valve so that the excess air ratio of the air-fuel mixture becomes a predetermined value. An arrangement is made to prevent an ignition failure from occurring in an attempt to perform an ignition operation in a state in which, due to a trouble with the variable throttle valve of remaining opened or remaining closed, the excess air ratio of the air-fuel mixture becomes too small or too excessive. The variable throttle valve is provided with a sensing device.

Abstract: A premixing apparatus has a butterfly valve provided in an air supply passage, a zero governor and a variable throttle valve interposed in a gas supply passage. A control is performed to switch a combustion capacity between at least two stages of a large-capacity stage and a small-capacity stage through change in opening degrees of the butterfly valve and the variable throttle valve.

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 plate-type heat exchanger includes blocks stacked on each other, each of the blocks including a heat exchanger body configured to exchange heat between a first fluid and a second fluid. A connection passage for the first fluid is formed between blocks adjacent to each other of the plurality of blocks, the connection passage allowing the outlet of one of the blocks adjacent to each other and the inlet of the other of the blocks adjacent to each other to communicate with each other, the first fluid in the blocks adjacent to each other having different flow directions between the blocks adjacent to each other, and a second connection passage is provided between at least one pair of blocks adjacent to each other among the plurality of blocks, the second connection passage being configured to cause the first fluid to flow to a position different from the connection passage.

Abstract: A heat transfer fin (1) includes a plurality of heat-transfer-tube insertion holes (10) aligned in a single stage, a downstream cut portion (3) formed so as to be recessed toward an upstream side of a gas flow passage of combustion exhaust gas, a downstream flange (13) formed on a peripheral edge of the downstream cut portion (3) so as to protrude from one surface of the heat transfer fin (1), and a plurality of first protruding pieces (4a) (4b) (4c) formed between the heat-transfer-tube insertion hole (10) and the downstream flange (13) so as to protrude alternately from both surfaces of the heat transfer fin (1).

Abstract: The present invention improves the user-friendliness of a hot-water supply apparatus when using hot water supply and air conditioning. A switching control unit 27, which switches between heat medium flow paths 4 and 5 according to an air conditioning ready state or a hot-water supply ready state, switches a heat medium flow path to the hot-water supply ready state by a switching valve 21 in the case where air conditioning is not used by the time an air conditioning standby time elapses during standby in the air conditioning ready state.

Abstract: The water heater may be configured to execute a normal operation in which a heating means is continuously operated in an ON state in a case where a required heat quantity is greater than or equal to a minimum heat quantity. The water heater may be configured to execute an intermittent operation in which the heating means is alternately and repeatedly operated in the ON state and an OFF state repeatedly in a case where the required heat quantity is less than the minimum heat quantity. The water heater may be configured to change a distribution ratio of a flow control mechanism in the normal operation and in the intermittent operation. An operating speed of the flow control mechanism in the intermittent operation may be faster than an operating speed of the flow control mechanism in the normal operation.

Abstract: A heat exchanger (1) includes a heat exchanging body (20) disposed within an outer box (10). A supply pipe (21) and a discharge pipe (22) in fluid communication with the heat exchanging body (20) respectively extend through first and second insertion holes (31, 32) in the outer box (10). Elastic seal members (40; 240) are respectively provided around the supply pipe (21) and the discharge pipe (22) and between a first sidewall (11) of the outer box (10) and the heat exchanging body (20). At least one biasing member (50; 250) exerts a lateral biasing force (F1; F2) on the elastic seal members (40; 240), thereby maintaining the elastic seal members (40; 240) in a state of compressive deformation and contacting the outer box (10) and the heat exchanging body (20) in an air-tight manner to block potential leakage paths (LP1; LP2) via the insertion holes (31, 32).

Abstract: A controller memorizes an accumulated combustion time by accumulating combustion time of a burner, and is set in a first lower-limit and a second lower-limit higher than the first lower-limit as a lower-limit lower than an initial value of an excess air ratio when reducing an excess air limit of a mixture gas of combustion air and a fuel gas, and the former is the lower-limit in case the accumulated combustion time is under a predetermined set time and the latter is the one in case the accumulated combustion time is the predetermined set time and over.

Abstract: An electrically operated gas flow regulating valve in which a needle valve body (2) is moved axially through a motion conversion mechanism (4) by the rotation of an electric motor (3). The motion conversion mechanism (4) includes: a guide tube (5) in which is formed axially elongated slits (51) with which cam pins (21) fixed to the needle valve (2) are slidably engaged; and a tubular cam body (6) having a spiral cam part with which the cam pins (21) are engages through elongated slits (51). In an arrangement in which one of the guide tube (5) and the cam body (6), e.g., the guide tube (5), is rotated by the electric motor (3), hysteresis is restrained from occurring. The cam part disposed in the cam body (6) is constituted by a spirally inclined sides (61) with which the cam pins (21) are brought into contact from axial one direction. A spring member (7) is disposed so as to urge the cam pins (21) in the other of the axial directions toward the spirally inclined sides (61).

Abstract: A heating and hot-water supply apparatus shortens the time taken for hot-water supply to stabilize at a set temperature in response to a request for a hot-water supply operation during a heating operation. The apparatus performs, using a common heating medium heated by a heater, a heating operation by circulating the heating medium through a heating terminal, and a hot-water supply operation of heating service water through heat exchange with the heating medium circulated through a hot-water supply heat exchanger and supplying hot water. A distribution unit (three-way valve) changes a distribution ratio of the heating medium between the heating terminal and the hot-water supply heat exchanger. A controller controls an amount of heat generated by the heater for the heating operation or the hot-water supply operation, and stops heating with the heater when the temperature of the heating medium reaches a predetermined upper-limit temperature.