Abstract: Not only a cylindrical weight is inserted with a clearance around an outside of a first axis part or a second axis part that extends opposite to the first axis part and is movable freely in an axial direction but also an annular seat surface on which the cylindrical weight is able to be seated by self-weight is provided with a governor valve. A projecting part(s) is provided with only a part in circumferential direction of one of the annular seat surface and a lower end surface of the cylindrical weight. The cylindrical weight is made sure to be supported on the annular seat surface in an inclined state from an upright posture by contact of the projecting part(s) with the other of the annular seat surface and the lower end surface of the cylindrical weight.

Abstract: Not only a cylindrical weight is inserted with a clearance around an outside of a first axis part or a second axis part that extends opposite to the first axis part and is movable freely in an axial direction but also an annular seat surface on which the cylindrical weight is able to be seated by self-weight is provided with a governor valve. A projecting part(s) is provided with only a part in circumferential direction of one of the annular seat surface and a lower end surface of the cylindrical weight. The cylindrical weight is made sure to be supported on the annular seat surface in an inclined state from an upright posture by contact of the projecting part(s) with the other of the annular seat surface and the lower end surface of the cylindrical weight.

Abstract: In a premixing apparatus that mixes a fuel gas with air and supplies an air-fuel mixture to a burner through a fan, includes a main valve, a zero governor, and a variable throttle valve which are interposed from an upstream side downward in sequence in a gas supply passage, of which an downstream end is connected to a gas suction part that is provided in an air supply passage on an upstream side of a fan, and carries out a first control that regulates an opening degree of the variable throttle valve so that an excess air ratio of the air-fuel mixture, which is indexed based on a flame current that is detected by a flame rod which is exposed in flames of the burner, and a second control that, at time of a post-purge operation, if the flame rod detects the flame current, it will be decided that an open trouble of the main valve occurs and the opening degree of the throttle valve will be tightened till a minimum opening-degree which is set so that the burner is extinguished.

Abstract: In a premixing apparatus that mixes a fuel gas with air, supplies an air-fuel mixture to a burner through a fan, and carries out a control that regulates an opening degree of a variable throttle valve, which is interposed in a gas supply passage, so that an excess air ratio of an air-fuel mixture becomes an appropriate value, in a case where a detected excess air ratio deviates to one side, e.g., a large side, from an acceptable range, a motor is repeatedly caused to rotate by a unit-angle in an opening-degree increasing direction until the detected excess air ratio becomes an appropriate value. In a case where the detected air ratio deviates to the other side, e.g.

Abstract: In a fan apparatus that includes a passage, a switching device, and a control device, on a premise that at a state where an effective sectional area at a predetermined portion of the passage is switched to a predetermined first-area by the switching device, a value of a current flowing to the fan when a rotational speed of the fan is made to a predetermined rotational speed is defined as a first fan-current value, at a state where the effective sectional area at the predetermined portion of the passage is switched to a predetermined second-area which is larger than that of the first area by the switching device, the value of the current flowing to the fan when the rotational speed of the fan is made to the predetermined rotational speed is defined as a second fan-current value, and a ratio of the first fan-current value to the second fan-current value is defined as a detected current ratio, a control device is configured to: memorize as a standard current ratio a detected current ratio that is detected when t

Abstract: A premixing apparatus that mixes a fuel gas with air and supplies an air-fuel mixture in a burner through a fan includes a control device that is configured to carry out a third control that: calculates and memorizes a lower limit of a rotational speed of a fan, at which an increase of an opening degree of a variable throttle valve becomes necessary, as a first threshold; and when the rotational speed of the fan increases to the first threshold or faster next time, immediately changes the opening degree of the variable throttle valve to an increased opening degree, which is larger than a predetermined standard opening degree and is obtained by multiplying a deviation of the rotational speed of the fan from the first threshold by a predetermined coefficient.

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 premixing apparatus for mixing air with a fuel gas in order to supply a burner with an air-fuel mixture through a fan, wherein a downstream end of a gas supply passage is connected to a gas suction part disposed in a portion, on an upstream side of the fan, of an air supply passage. The gas supply passage has interposed therein a zero governor for adjusting a secondary gas pressure to an atmospheric pressure. Even if the calorific value of the fuel gas may fluctuate, excess air ratio of the air-fuel mixture is arranged to be maintained at a constant value. The premixing apparatus is provided with: an excess air ratio detection device for detecting an excess air ratio of the air-fuel mixture; and a flow control valve interposed in a portion, on a downstream side of the zero governor, of the gas supply passage. The flow control valve is controlled such that the excess air ratio of the air-fuel mixture detected by the excess air ratio detection device becomes constant.