Premixing apparatus

Patent metadata

Field	Value
Publication number	US-12055292-B2
Application number	US-202217689681-A
Country	US
Kind code	B2
Filing date	Mar 8, 2022
Priority date	Mar 26, 2021
Publication date	Aug 6, 2024
Grant date	Aug 6, 2024

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.

First claim

The invention claimed is:

1. A premixing apparatus for mixing air with a fuel gas to supply a burner with an air-fuel mixture through a fan, including:
a zero governor for regulating a secondary gas pressure to an atmospheric pressure, the zero governor being interposed in a gas supply passage whose downstream end is connected to a gas suction part disposed in an air supply passage on an upstream side of the fan; a motor-driven type of variable throttle valve interposed in a portion, on a downstream side of the zero governor, of the gas supply passage; an excess air ratio detecting device for detecting an excess air ratio of the air-fuel mixture; and a control device to perform control to adjust the opening degree of the air-fuel mixture so that the excess air ratio of the air-fuel mixture to be detected by the excess air ratio detecting device becomes a predetermined value;
wherein the variable throttle valve is provided with a sensing device for sensing a movement of a valve body of the variable throttle valve, and
wherein the control device is constructed such that, at a time of ignition at the burner, a motor of the variable throttle valve is rotated sequentially in one and an opposite of a valve-closing direction and a valve-opening direction and that, only when the movement of the valve body of the variable throttle valve by this rotation has been sensed by the sensing device, ignition control is performed.

2. The premixing apparatus according to claim 1 , wherein, at the time of ignition at the burner, the motor of the variable throttle valve is once rotated in the valve-closing direction and then rotated in the valve-opening direction such that the valve body of the variable throttle valve is moved to a predetermined ignition position.

3. The premixing apparatus according to claim 1 , wherein the valve body of the variable throttle valve has a needle part that is insertable into a valve hole formed in a valve seat of the variable throttle valve,
wherein: the variable throttle valve has a diaphragm that lies opposite to the needle part, the diaphragm being positioned on a downstream side of the valve seat; the diaphragm is arranged to be displaced by a push of the valve body as a result of movement of the valve body of the variable throttle valve in the closing direction; and the sensing device is arranged to detect the displacement of the diaphragm.

4. The premixing apparatus according to claim 2 , wherein the valve body of the variable throttle valve has a needle part that is insertable into a valve hole formed in a valve seat of the variable throttle valve,
wherein: the variable throttle valve has a diaphragm that lies opposite to the needle part, the diaphragm being positioned on a downstream side of the valve seat; the diaphragm is arranged to be displaced by a push of the valve body as a result of movement of the valve body of the variable throttle valve in the closing direction; and the sensing device is arranged to detect the displacement of the diaphragm.

Assignees

• Rinnai Kk

Inventors

• Noritake Katsuya
• Miura Takuya

Classifications

• F23N2231/10

  for component failures · CPC title

• F23N2235/24

  Valve details · CPC title

• F23N2235/16

  variable flow or proportional valves · CPC title

• F24H1/107

  using fluid fuel · CPC title

• F23L5/02

  Arrangements of fans or blowers · CPC title