# US 10,480,783 B2 · Positive pressure amplified gas-air valve for a low NOx premix combustion system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,480,783 B2 - Document ID: US10480783B2 - Status: Granted - Kind: B2 - Application number: 15/690,509 - Filed: 2017-08-30 - Published: 2019-02-28 - Granted: 2019-11-19 - Earliest claimed: 2017-08-30 - Assignees: Lennox Industries Inc. - Applicants: Lennox Industries Inc. - Inventors: Glenn W. Kowald - Web page: https://patentgrep.com/patent/US10480783B2 ## CPC - F23D 14/04: induction type, e.g. Bunsen burner - F23N 1/027: {using mechanical means} - F24D 5/04: with return of the air or the air-heater - F24H 3/065: {using fluid fuel} - F24H 3/087: {using fluid fuel} - F24H 9/1881: using fluid fuel - F23N 2235/20: Membrane valves - F23D: BURNERS - F23N: REGULATING OR CONTROLLING COMBUSTION (control devices specially adapted for combustion apparatus in which combustion takes place in a fluidised bed of fuel or other particles F23C10/28; condition responsive controls for regulating combustion in domestic stoves with open fires for solid fuel F24B1/187) - F24D: DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR (using steam or condensate extracted or exhausted from steam engine plants for heating purposes F01K17/02) - F24H: FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL (steam generation F22) ## Abstract 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. ## Claims ### Claim 1 A premix combustion system for a furnace in an HVAC system, comprising: a chamber operable to receive gas and air and deliver a gas-air mix to a combustion chamber, the chamber comprising an air inlet operable to receive an air supply; a gas valve, the gas valve comprising a gas line extending from the gas valve to the chamber at a location downstream from the air inlet, the gas valve further comprising a gas supply inlet operable to receive gas from a gas source; an amplifier comprising; an air interface pneumatically coupled to the air supply; a secondary interface proximate the air interface and pneumatically coupled to a secondary location in the HVAC system; and a regulator coupled to the amplifier and coupled to the gas valve; wherein the amplifier is configured to detect a pressure differential between the air supply and the secondary location, and to cause the regulator coupled to the gas valve to apply an amplified pressure to gas in the gas line. ### Claim 2 (depends on 1) The premix of claim 1 wherein the secondary location comprises an outlet. ### Claim 3 (depends on 1) The premix of claim 1 wherein the secondary location comprises an exhaust line. ### Claim 4 (depends on 1) The premix of claim 1 wherein the chamber comprises flow restrictors. ### Claim 5 (depends on 1) The premix of claim 1 wherein the regulator linkage applies a 4:1 amplification to the gas valve. ### Claim 6 (depends on 3) The premix of claim 3 wherein if the secondary location is exposed to atmospheric pressure then the regulator turns off the gas valve. ### Claim 7 (depends on 1) The premix of claim 1 wherein the secondary location is in the chamber downstream of the air inlet. ### Claim 8 (depends on 1) The premix of claim 1 wherein the regulator further comprises a membrane between the air interface and the secondary interface. ### Claim 9 A furnace for use in an HVAC system, comprising: a premix combustion system, comprising; a chamber operable to receive gas and air and deliver a gas-air mix to a combustion chamber, the chamber comprising an air inlet operable to receive an air supply; a gas valve, the gas valve comprising a gas line extending from the gas valve to the chamber at a location downstream from the air inlet, the gas valve further comprising a gas supply inlet operable to receive gas from a gas source; an amplifier comprising; an air interface pneumatically coupled to the air supply; a secondary interface proximate the air interface and pneumatically coupled to a secondary location in the HVAC system; and a regulator coupled to the amplifier and to the gas valve, wherein the amplifier is configured to detect a pressure differential between the air supply and the secondary location, and to cause the regulator coupled to the gas valve to apply an amplified pressure to gas in the gas line; one or more heat exchangers operable to receive combusted gas-air mix from the combustion chamber; one or more inducers operable to induce the flow of combusted gas-air mix through the one or more heat exchangers; one or more blowers operable to direct air flow across the one or more heat exchangers; and an exhaust operable to direct combusted gas-air mix from the one or more heat exchangers to an exhaust vent. ### Claim 10 (depends on 9) The furnace of claim 9 wherein the secondary location comprises an outlet. ### Claim 11 (depends on 9) The furnace of claim 9 wherein the secondary location comprises an exhaust line. ### Claim 12 (depends on 9) The furnace of claim 9 wherein the chamber comprises flow restrictors. ### Claim 13 (depends on 9) The furnace of claim 9 wherein the amplifier coupled to the regulator applies a 4:1 amplification to the gas valve. ### Claim 14 (depends on 11) The furnace of claim 11 wherein if the secondary location is exposed to atmospheric pressure then the regulator turns off the gas valve. ### Claim 15 (depends on 9) The furnace of claim 9 wherein the secondary location is in the chamber downstream of the air inlet. ### Claim 16 (depends on 9) The furnace of claim 9 wherein the amplifier further comprises a membrane between the air interface and the secondary interface. ### Claim 17 A method of operating a furnace in an HVAC system, comprising: providing a premix chamber configured to receive an air supply and a gas supply and to supply a gas-air mix to a combustion chamber; providing a gas valve comprising a gas supply inlet configured to receive the gas supply from a gas source and a gas line configured to deliver the gas supply to the premix chamber; receiving the air supply in the premix chamber at an air inlet; receiving the gas supply in the premix chamber from the gas line connected to the premix chamber downstream of the air inlet; providing an amplifier operable to detect a pressure differential between a first interface and a second interface, coupling the amplifier to the regulator and further operable to apply a pressure differential to the gas supply in the gas line; coupling the first interface pneumatically to the air supply; coupling the second interface pneumatically to a secondary location in the HVAC system; receiving the gas-air mix in the combustion chamber; igniting the gas-air mix in the combustion chamber; and providing the ignited gas-air mix to another component of the furnace. ### Claim 18 (depends on 17) The method of claim 17 wherein the secondary location comprises an exhaust line. ### Claim 19 (depends on 17) The method of claim 17 wherein the secondary location comprises a location in the premix chamber downstream from the gas inlet. ### Claim 20 (depends on 17) The method of claim 17 wherein the regulator linkage applies a 4:1 amplification to the gas valve. ### Claim 21 (depends on 17) The method of claim 17 wherein the regulator comprises a membrane between the first and second interface.