# US 10,480,784 B2 · Inlet screen assembly for ultra low NOx gas-air mixing system

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- Number: US 10,480,784 B2
- Document ID: US10480784B2
- Status: Granted
- Kind: B2
- Application number: 15/674,313
- Filed: 2017-08-10
- Published: 2019-02-14
- Granted: 2019-11-19
- Earliest claimed: 2017-08-10
- Assignees: Lennox Industries Inc.
- Applicants: Lennox Industries Inc.
- Inventors: Glenn W. Kowald
- Web page: https://patentgrep.com/patent/US10480784B2

## CPC

- F23D 14/68: Treating the combustion air or gas, e.g. by filtering, or moistening
- B01D 39/12: of wire gauze; of knitted wire; of expanded metal
- B01D 46/0005: {Mounting of filtering elements within casings, housings or frames (B01D46/2422 takes precedence)}
- F24H 9/2085: {using fluid fuel}
- B01D 46/103: {Curved filtering elements}
- B01D 2275/10: Multiple layers
- F23D: BURNERS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- 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 for a screen assembly for gas-air mixers in HVAC systems, such as for furnaces. A screen assembly can comprise a mesh screen, a housing, and a pressure tap. The mesh screen can allow for the intake of an air supply while also blocking unwanted foreign matter such as dust or leaves. The housing can receive the air supply and direct it into a gas-air mixer or other component. The pressure tap can be coupled to a gas valve or regulator in order to modulate the flow of gas when air flow is restricted.

## Claims

### Claim 1

A premix assembly for use with a furnace in an HVAC system comprising:
a mixing chamber operable to mix a supply of air and a supply of gas and to provide a gas-air mix to another component in the HVAC system;
a screen assembly coupled to the mixing chamber, operable to receive the supply of air from outside of the mixing chamber, and comprising:
a screen on one end of the screen assembly operable to receive the supply of air therethrough and operable to deflect at least one type of foreign matter;
a housing operable to couple with the screen and hold it in place, and configured to receive the supply of air and direct it into the mixing chamber;
a pressure tap coupled to the housing and configured to be pneumatically coupled to another location in the HVAC system; and
a gas valve configured to direct the supply of gas into the mixing chamber.

### Claim 2 (depends on 1)

The premix assembly of claim 1 wherein the screen comprises a spherical shape.

### Claim 3 (depends on 1)

The premix assembly of claim 1 wherein the housing and the screen are coupled by preloading at least a portion of the screen.

### Claim 4 (depends on 1)

The premix assembly of claim 1 wherein the pressure tap is pneumatically coupled to the gas valve.

### Claim 5 (depends on 1)

The premix assembly of claim 1 wherein the screen comprises a sound deadening material.

### Claim 6 (depends on 1)

The premix assembly of claim 1 wherein the housing comprises a plastic.

### Claim 7 (depends on 1)

The premix assembly of claim 1 wherein the screen comprises multiple layers.

### Claim 8 (depends on 1)

The premix assembly of claim 1 wherein the screen assembly further comprises a Helmholtz resonator or a quarter-wave tube.