Systems and methods are described related to a premix combustion system used in a furnace system. Prior systems have to create a negative pressure in the premix chamber to draw gas into the chamber. Embodiments under the current disclosure can use an amplifier that is pneumatically coupled to an air supply and a secondary location (besides the gas valve). Coupling to the amplifier to a location apart from the gas valve allows the system to avoid a negative pressure in the mixing chamber. The amplifier can apply an amplified pressure or signal to a gas valve regulator and thereby raise the gas pressure so that the gas supply is driven into the premix chamber.

A regulating device may include a housing that defines an inlet chamber and an outlet chamber, with a flow restriction seat between the inlet chamber and the outlet chamber. A flow restriction valve is movable relative to the flow restriction seat to adjust the flow between the inlet chamber and the outlet chamber of the regulating device. A servo valve having a servo chamber may be used to adjust the position of the flow restriction valve. The servo chamber may be fluidly coupled to the inlet chamber though a fixed flow restriction and to the outlet chamber though an adjustable flow restriction. A stepper motor may be used to adjust the servo valve to adjust the adjustable flow restriction between the servo chamber and the outlet chamber. This causes a change of the servo pressure, which moves the flow restriction valve and adjusts the flow of the regulating device.

A gas valve includes a valve seat, a valve stem, a valve body, and a valve diaphragm. The valve body acts together with the valve seat in such a way that the gas valve is in a closed state when the valve body is pressed against the valve seat and the gas valve is in an opened state when the valve body is lifted up from the valve seat. In a partially opened state, a connection between the valve stem and the valve body allows the valve body to tilt relative to the valve stem. The tilt may help provide more stable contact between the valve body and the valve seat when the gas valve is in the partially opened state. This can reduce wear on the gas valve by reducing, for example, valve body bounce.

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.

A premixing apparatus includes a mixing unit, an air supply adjusting unit, and a gas switching unit. The mixing unit draws a fuel gas in the mixing unit by supplied air to mix the fuel gas and the supplied air with each other. The air supply adjusting unit applies a load on the supplied air flowing toward the mixing unit and switches the load. The gas switching unit switches a gas amount of the fuel gas to be supplied to the mixing unit.

A fluid regulator having a valve body defining an inlet, an outlet, a loading port, an access port, and a loading chamber disposed within the valve body and coupled to the loading port. A valve assembly is at least partially disposed between the inlet and the outlet and in communication with the loading chamber and is adapted to cooperate with the loading chamber to adjust fluid flow at the outlet by adjusting a fluid flow rate between the inlet and the outlet. A restrictor is at least partially disposed within the access port and the loading chamber and the valve assembly are adapted to be responsive to a change in loading pressure such that a modified rate is achieved and the restrictor is adapted to adjust a response speed in which the modified rate is achieved.

A gas flow controller for use in a gas-fired apparatus including a pilot burner and a main burner is provided. The controller includes a housing defining a diaphragm chamber, a pilot valve operable to open and close a first fluid flow path between a gas supply inlet of the gas flow controller and the diaphragm chamber, and a main burner valve operable to open and close a second fluid flow path between the gas supply inlet and the main burner. The main burner valve includes a diaphragm that is disposed within the diaphragm chamber and includes a central portion and an annular outer portion. The outer portion is configured to deflect into engagement with the housing to close a third fluid flow path in response to an over-pressure condition at the gas supply inlet.

A burner includes: an adaptor to which a fuel supply box for supplying fuel is connected, and having a fuel inlet; a combustion part configured to perform combustion while fuel injected from the fuel inlet is discharged through a flow path; a connection housing disposed between the adaptor and the combustion part, having a fuel supply path communicated with the fuel inlet, and configured to feed fuel of the fuel supply box to the combustion part; an inflow fuel control part provided at one side of the connection housing, and configured to control the amount of fuel injected by controlling an open degree of the fuel inlet; and a feed fuel control part provided at another side of the connection housing, and configured to control the amount of fuel supplied to the combustion part by controlling an open degree of one side of the fuel supply path.

Fluid control apparatus having flow restrictors are described herein. An example actuator includes an actuator housing having an actuator to define a first chamber of the actuator housing and a second chamber of the actuator housing. A loading fluid pathway is formed in the actuator housing to fluidly couple a loading fluid and the first chamber. A restrictor is positioned within the loading fluid pathway to regulate a flow rate of the loading fluid that is to flow from an inlet port of the loading fluid pathway to the first chamber.

A regulating device may include a housing that defines an inlet chamber and an outlet chamber, with a flow restriction seat between the inlet chamber and the outlet chamber. A flow restriction valve is movable relative to the flow restriction seat to adjust the flow between the inlet chamber and the outlet chamber of the regulating device. A servo valve having a servo chamber may be used to adjust the position of the flow restriction valve. The servo chamber may be fluidly coupled to the inlet chamber though a fixed flow restriction and to the outlet chamber though an adjustable flow restriction. A stepper motor may be used to adjust the servo valve to adjust the adjustable flow restriction between the servo chamber and the outlet chamber. This causes a change of the servo pressure, which moves the flow restriction valve and adjusts the flow of the regulating device.