Differential Gas Pressure At Burner Inlet

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Duct burners - “NP” & “RG” AIRFLO burner4 - 21.5 - 7E - i - 9/15Specifications of "NP" & "RG" AIRFLO burnersNP-I & NP-II AIRFLO burnersDifferential gas pressure at burner inletFor burner capacity 0.5 MBtu/h/ftnatural gaspropaneFuel(1000 Btu/ft³ HHV, sg 0.6)(2500 Btu/ft³ HHV, sg 1.57)NP-I5“ wc2“ wcNP-II2-1/2“ wc1“ wcNote : For other capacities per foot or gases with different heating values and/or specific weights as shown in the above table, valuesfor differential gas pressure will behave according to the normal laws of physics. Listed values are approximate net pressures at burner inlet, NOT taking into account any losses in piping/gas manifolds etc. Stated pressures are indicative. Actual pressures are function of altitude, type of fuel, gas quality.Optimum operation parameters550Operation in this arearequires specialconsiderations125008Optimum design area4504006350300220024002600280030003200approx. flame length in inchesMax capacity KBtu/h/ft (HHV)6003400air velocities (sfpm)Note : Flame length is as measured from leading edge of mixing plates (see sketch on page 4-21.5-11).EXAMPLE: Series NP-I AIRFLO burner at 3000 sfpm and at 0.5 MBtu/h per foot would have an approximate flame length of10 in. Contact MAXON for operation outside the optimum operation area. Airstream velocity across and through the burner’s mixing plates must be kept uniform and within desired limits by use of asilhouette profile plate through which the burner fires. Refer to page 4-21.5-11 for more details on sizing of this profile plate. Pilot capacities are nominally rated at 25,000 Btu/h with natural gas differential pressure of 4” wc to 6” wc.Suitable for natural gas, propane and propane-air mixtures.Contact MAXON for applications on butane or other gases than specified here.Minimum capacitiesMinimum capacities are given as a guideline. They strongly depend on process conditions.Air velocities sfpmNP-IMinimum capacity KBtu/h/ft (HHV)NP-IInatural gaspropanenatural 24202224283020232527292325283033not recommended15not recommendedw w w . m a x o n c o r p . c o mcombustion systems for industryMAXON reserves the right to alter specifications and data without prior notice. 2010 Copyright Maxon Corporation. All rights reserved.18

4 - 21.5 - 8E - i - 9/15Duct burners - “NP” & “RG” AIRFLO burnerNP-III AIRFLO burnersDifferential gas pressure at burner inletFor burner capacity 1 MBtu/h/ftFuelNP-IIInatural gas(1000 Btu/ft³ HHV, sg 0.6)5” wcpropane(2500 Btu/ft³ HHV, sg 1.57)2” wcNote : For other capacities per foot or gases with different heating values and/or specific weights as shown in the above table, valuesfor differential gas pressure will behave according to the normal laws of physics. Listed values are approximate net pressures at burner inlet, NOT taking into account any losses in piping/gas manifolds etc. Stated pressures are indicative. Actual pressures are function of altitude, type of fuel, gas quality.Optimum operation parameters36Max capacity KBtu/h/ft (HHV)Operation in this arearequires specialconsiderations1200110024100022Optimum design prox. flame length in inches3213005000air velocities (sfpm)Note : Flame length is measured from leading edge of mixing plate (see sketch on page 4-21.5-11).EXAMPLE: Series NP-III AIRFLO burner at 4000 sfpm and 1 MBtu per foot would have an approximate flame length of 30 in.Contact MAXON for operation outside the optimum operation area (shaded area). Airstream velocity across and through the burner’s mixing plates must be kept uniform and within desired limits by use of asilhouette profile plate through which the burner fires. Refer to page 4-21.5-11 for more details on sizing of this profile plate. Pilot capacities are nominally rated at 25,000 Btu/h with natural gas differential pressure of 4” wc to 6” wc.Suitable for natural gas, propane and propane-air mixtures. Contact MAXON for applications on butane or other gases thanspecified here.Minimum capacitiesMinimum capacities are given as a guideline. They strongly depend on process conditions.Air velocities sfpmMinimum capacity KBtu/h/ft tural 8175195215w w w . m a x o n c o r p . c o mcombustion systems for industryMAXON reserves the right to alter specifications and data without prior notice. 2010 Copyright Maxon Corporation. All rights reserved.

Duct burners - “NP” & “RG” AIRFLO burner4 - 21.5 - 9E - i - 9/15RG-IV AIRFLO burnersDifferential gas pressure at burner inletFor burner capacity 0.5 MBtu/h/ftFuelnatural gasRG-IV(1000 Btu/ft³ HHV, sg 0.6)5” wcNote : For other capacities per foot or gases with different heating values and/or specific weights as shown in the above table, valuesfor differential gas pressure will behave according to the normal laws of physics. Listed values are approximate net pressures at burner inlet, NOT taking into account any losses in piping/gas manifolds etc. Stated pressures are indicative. Actual pressures are function of altitude, type of fuel, gas quality.Optimum operation parameters2.418550500Operation in this arearequires specialconsiderations126450400Optimum design area350300250200approx. flame length in inchesMax capacity KBtu/h/ft (HHV)60015013001600190022002500280031003400air velocities (sfpm)Note : Flame length is as measured from leading edge of mixing plates (see sketch page 4-21.5-11).EXAMPLE: Series RG-IV AIRFLO burner used with 2-speed blower at 3000 sfpm and 0.5 MBtu/h per foot or at 1500 sfpmand 0.25 MBtu/h per foot (flame length 14 in. – 0.5 MBtu/h / 10 in. – 0.25 MBtu/h).Contact MAXON for operation outside the optimum operation area (light grey area). Airstream velocity across and through your burner’s mixing plates must be kept uniform and within desired limits by use of asilhouette profile plate through which the burner fires. Refer to page 4-21.5-11 for more details on sizing of this profile plate. Pilot capacities are nominally rated at 25,000 Btu/h with natural gas differential pressure of 4” wc to 6” wc. For natural gasonly. Contact MAXON for applications on butane, propane, or other gases than natural gas. Capacity at half speed should be limited with fail-safe security.Minimum capacitiesMinimum capacities are given as a guideline. They strongly depend on process conditions.Air velocities sfpmMinimum capacity KBtu/h/ft (HHV)RG-IVnatural gas160019002200250028003100340013151618202432w w w . m a x o n c o r p . c o mcombustion systems for industryMAXON reserves the right to alter specifications and data without prior notice. 2010 Copyright Maxon Corporation. All rights reserved.

4 - 21.5 - 10E - i - 9/15Duct burners - “NP” & “RG” AIRFLO burnerMaterials of constructionNP-I, NP-II, NP-III, RG-IVBurner bodyMixing plates1 piece endplatesgray iron ASTM A159-77 Grade G3000AISI 430 W.S. 1.4016NP-I-AL, RG-IV-ALAluminumAISI 430 W.S. 1.4016[1] gray iron ASTM A159-77 Grade G3000steel platedflangegray iron ASTM A159-77 Grade G3000steel platedplateAISI 430 W.S. 1.4016AISI 430 W.S. 1.4016Aluminized and galvanized steelAluminized and galvanized steel2 piece endplatesFasteners[1] NP onlyw w w . m a x o n c o r p . c o mcombustion systems for industryMAXON reserves the right to alter specifications and data without prior notice. 2010 Copyright Maxon Corporation. All rights reserved.

4 - 21.5 - 11E - i - 9/15Duct burners - “NP” & “RG” AIRFLO burnerSelection criteriaAir-stream velocityAir-stream velocity across and through the burner’s mixing plates must be kept uniform and within desired limits by use of asilhouette profile plate through which the burner fires. A 6 in. (minimum) profile plate should be installed surrounding the interiorduct walls at the leading edge of the burner mixing plates.1) Direction of process airmovement3A22) Adjustable profile plate3) Fixed profile plate4) Universal support bracket415) Differential pressure switchBLA : Minimum 6 in.150150100B : Minimum 6 in.L : Flame length5Optimum design ranges for Series "NP" and "RG" AIRFLO burners are shown in the graphs on page 4-21.5-7, page 4-21.5-8and page 4-21.5-9. Velocities in sfpm are measured with a velometer directly in the duct at the plane of the profile plate and leadingedge of burner mixing plates (see above sketch).To determine profile opening areas, add burner displacement areas (ft²/section) from table on page 4-21.5-12 for completeburner assembly to “Net Free Area” of duct :“Net free area” of duct (ft²) Fan volume ----Velocity (sfpm)scfm fan volume at 288 Kelvin and 1 atmosphereNet free area (ft²) burner displacement (ft²) profile area (ft²)The relation between velocity and pressure differential across the burner slightly differ with the ratio between net profile area andtotal duct section.Velocities should always be confirmed and established by use of a velometer on actual field site installation.Velocity factors (fresh air - 60 Fρ 1,293 kg/Nm3)Velocityfpm1600 1800200022002400 2600 28003000325035003750 4000 4500Air pressure differential “wc0.16 0.200.250.300.360.570.640.770.880.420.491.00 1.26Note: differential air pressures are measured via pressure test points located 6 in. upstream and 6 in. downstream of the profile plate,near the duct wall at 4 in. into the duct. (See sketch on page 4-21.5-11) typical data which may not represent precise pressure drops for all design cases.w w w . m a x o n c o r p . c o mcombustion systems for industryMAXON reserves the right to alter specifications and data without prior notice. 2010 Copyright Maxon Corporation. All rights reserved.

4 - 21.5 - 12E - i - 9/15Duct burners - “NP” & “RG” AIRFLO burnerInlet feed limitationsThe maximum number of units of burner per gas inlet connection should be limited in order to guarantee correct gas distributioninside the burner manifold. Insufficient or badly distributed gas inlet connections may affect flame length, pollutant emissions andtemperature distribution downstream of the burner. Refer to the table below as a guideline for natural gas, based on a maximumcapacity limitation of 0.5 MBtu/h/ft (NP-I & NP-II) and 1 MBtu/h/ft (NP-III). The number of gas inlets should be reconsidered forgases different from natural gas (for example gases with lower calorific value).Contact MAXON for more details.NP-I 4 ft 5 ft1 1/4” end inlet flange1 1/2” back inletsNP-II 4 ft 5 ftNP-III 2 ft 4 ftRG-IV 4 ft 5 ftBurner sectionsBurner typeNP-INP-IINP-IIIRG-IVNP-ICast iron bodies with AISI 430 mixing platesandcarbon steel fastenersRG-IVNP-IAlu bodies with AISI 321 mixingplates andcarbon steel fastenersDescriptionRG-IVAlu bodies with AISI 321 mixing platesandstainless steel fastenersSketchDesignation[1]6 in. straight sectionNP-I-6NP-II-6NP-III-6RG-IV-6NP-I-6 (AL)RG-IV-6 (AL)NP-I-6 (ALSS)RG-IV-6 (ALSS)12 in. straight sectionNP-I-12NP-II-12NP-III-12RG-IV-12NP-I-12 (AL)RG-IV-12 (AL)NP-I-12 (ALSS)RG-IV-12 (ALSS)1218 in. straight sectionNP-I-18NP-II-18NP-III-18RG-IV-18N/A [2]N/AN/AN/A324 in. straight A46 in. x 6 in. elbow sectionNP-I-LNP-II-LNP-III-LRG-IV-LN/AN/AN/AN/A512 in. x 6 in. T-sectionNP-I-TNP-II-TNP-III-TRG-IV-TNP-I-T (AL)RG-IV-T (AL)NP-I-T(ALSS)RG-IV-T (ALSS)12 in. back inlet B (AL)RG-IV-12B (AL)36 in. back inlet /AN/A86 in. pilot assemblysection includes built-in 6NP-I-12B (ALSS) RG-IV-12B (ALSS)7[1] Sketch see page 4-21.5-13[2] N/A not applicableBurner displacement and weight [1]Burner typeNP-I / NP-II / NP-IIIRG-IVNP-ICast iron bodies with AISI 430 mixingplates and carbon steel 6 in. straight section0.25512 in. straight section0.509DescriptionRG-IVNP-IRG-IVAlu bodies with AISI 321 mixing plates and Alu bodies with AISI 321 mixing plates andcarbon steel fastenersstainless steel 70.505.70.666.70.505.70.666.7Weightlbs18 in. straight section0.75140.9915N/A (2)N/AN/AN/AN/AN/AN/AN/A24 in. straight section1.00181.3219.4N/AN/AN/AN/AN/AN/AN/AN/A6 in. x 6 in. elbow section0.4590.609.7N/AN/AN/AN/AN/AN/AN/AN/A12 in. x 6 in. 312 in. back inlet 136 in. back inlet section1.2026.51.5028.2N/AN/AN/AN/AN/AN/AN/AN/A6 in. pilot assemblysection includes built-in pilot0.2590.335.5N/AN/AN/AN/AN/AN/AN/AN/A[1] Sketches see page 4-21.5-13. Refer to page 4-21.5-19 for dimensions.[2] N/A not applicablew w w . m a x o n c o r p . c o mcombustion systems for industryMAXON reserves the right to alter specifications and data without prior notice. 2010 Copyright Maxon Corporation. All rights reserved.

Duct burners - “NP” & “RG” AIRFLO burner4 - 21.5 - 13E - i - 9/151234561) NP/RG-*-62) NP/RG-*-123) NP-*-18[1]4) NP-*-24[1]5) NP-*-L[1]6) NP/RG-*-T7) NP-12B7[1] not available in "RG" AIRFLO Note: mixing plates of Series "RG" AIRFLO burners are slightly longer. See dimensions on page 4-21.5-19.w w w . m a x o n c o r p . c o mcombustion systems for industryMAXON reserves the right to alter specifications and data without prior notice. 2010 Copyright Maxon Corporation. All rights reserved.

4 - 21.5 - 14E - i - 9/15Duct burners - “NP” & “RG” AIRFLO burnerPilots, end closures and end inlet flange sets for Series "NP" AIRFLO burnersAll open ends of burner assembly must be closed off with one of these end closures or pilots. One-piece cast end closures shouldnot be used if temperature rise exceeds 300 F.Series "NP" AIRFLO burnersDesignationDescriptionModelWeight (lbs)NP-ECOne piece end closure set3.9NP-EPTwo piece end plate set6.3NP-EC-SI-3/4" UV[1]One piece pilot set including SI with3/4"-NPT UV-connection4.1NP-EC-SI-1/2" FR[1]One piece pilot set including SI with1/2"-NPT 1/4"-EP-ISOOne piece pilot set including SI with 1-1/4" NPT gasinlet connection and FR/UV-connectionOne piece pilot set including SI with Rp 1-1/4 gas inletconnection and FR/UV-connectionTwo piece pilot set including SI with 1-1/4" NPT gasinlet connection and FR/UV-connectionTwo piece pilot set including SI with Rp 1-1/4 gas inletconnection and FR/UV-connection3.87.0Two piece End inlet flange set with 1-1/4" NPT gas inletconnectionTwo piece End inlet flange set with Rp 1-1/4 gas inletconnection6.4NP-PAK w/SI[1]Two piece pilot set with SI and FR/UV-connection7.2NP-PAK w/AO-SI[1]Two piece pilot set with SI, FR/UV-connection andadjustable orifice for pilot gas flow7.6NP-PAK w/AO-SI-cock-tube[1]Two piece pilot set with SI, FR/UV-connection,adj.orifice, cock and tubing for pilot gas flow8.8Pilot section w/Built-in pilot includes two piece pilot setwith SI and FR/UV-connection onto its own special 6"Series “NP” AIRFLO burner assembly10.0NP-6P pilot section[1] SI spark ignitor - UV connection for flame scannerFR connection for flame rodw w w . m a x o n c o r p . c o mcombustion systems for industryMAXON reserves the right to alter specifications and data without prior notice. 2010 Copyright Maxon Corporation. All rights reserved.

Duct burners - “NP” & “RG” AIRFLO burner4 - 21.5 - 15E - i - 9/15Pilots, end closures, and end inlet flange sets for Series "RG" AIRFLO burnersAll open ends of burner assembly must be closed off with one of these end closures or pilots. One-piece cast end closures shouldnot be used if temperature rise exceeds 300 FSeries "RG" AIRFLO burnersDesignationDescriptionRG-EP-2pcTwo piece end plate setRGF-1-1/4"-EP-2pc-ANSITwo piece end plate set with 1-1/4" NPT gas connectionModelWeight (lbs)2.22.2RGF-1-1/4"-EP-2pc-ISOTwo piece end plate set with Rp 1-1/4 gas connection[1]Two piece pilot set with SI,FR/UV-connection and 1-1/4" NPT gas connectionRGF-1-1/4"-FR-SI-2pc-ISO[1]Two piece pilot set with SI,FR/UV-connection and Rp 1-1/4 gas connectionRG-PAK pilot set w/SI-2pc[1]Two piece pilot set with SI and FR/UV-connection301RG-PAK pilot set w/AO-SI[1]Two piece pilot set with SI, FR/UV-connection andadjustable orifice for pilot gas flow3.4RG-PAK pilot setw/AO-SI-cock-tube[1]Two piece pilot set with SI, FR/UV-connection,adjustable orifice, cock and tubing for pilot gas flow4.6Pilot section w/Built-in pilot includes two piece pilot setwith SI and FR/UV-connection onto its own special 6"Series "RG" AIRFLO burner assembly9.3RGF-1-1/4"-FR-SI-2pc-ANSI2.9RG-6P pilot section[1] FR connection for flame rodSI spark ignitorw w w . m a x o n c o r p . c o mcombustion systems for industryMAXON reserves the right to alter specifications and data without prior notice. 2010 Copyright Maxon Corporation. All rights reserved.

4 - 21.5 - 16E - i - 9/15Duct burners - “NP” & “RG” AIRFLO burnerProcess flows and oxygen contentSeries "NP" AIRFLO and "RG" AIRFLO burners are used only for the heating of fresh air in motion. Fresh air means air with21 % oxygen, at ambient temperature, or indirectly preheated via a steam or water coil.It is not recommended to use the burner in recirculating air systems.NP-I , NP-II and RG-IV AIRFLO burners may be used if temperature rise does not exceed 840 FNP-III can be used to heat fresh air up to 1200 FMax. temperature of the fresh air entering the burner is 600 FVelocity and air flow at operating temperature must be uniform and constant for Series "NP" AIRFLO burners.Series "RG" AIRFLO burners can operate at 50 % and 100 % of the flow, typically applicable in two-speed air handling systems.Precautions should be taken to prevent overfiring of the burner in such conditions.Piloting & ignitionSeries "NP" and "RG" AIRFLO burners are standard equipped with raw gas pilots to ignite the main flame. Pilot burner isincorporated in the burner end plate. Depending on the burner configuration, MAXON offers the choice between a complete rangeof pilot end plate sets. See tables on page 4-21.5-14 and page 4-21.5-15 for proper selection or contact MAXON for more detailedinformation.Permanent pilot operation is not advised. Use main burner at minimum capacity for continuous operation.Also direct ignition of the burner is possible, as far as acceptable by local regulations.Use minimally 5000 V/200 VA ignition transformer for sparking of the spark ignitor. Contact MAXON for optional ignition equipmentin hazardous location.Locate one pilot valve close enough to the pilot burner gas inlet, to guarantee fast and reliable ignition of the pilot burner.Typical ignition sequence Pre-purge of the combustion chamber and installation, according to the applicable codes and the installation requirements.Gas control valve in minimum position.Pre-ignition (typically 2 s sparking in air). Open pilot gas valves and continue to spark (typically 5 s to 10 s).Stop sparking, continue to power the pilot gas valves and start flame detection. Trip the burner in case no flame detected fromthis point on.Check pilot flame stability (typical 5 s to 10 s to prove stable flame).Open main gas valves and allow enough time for the fuel gas to reach the burner (typical 5 s or the time that gas needs to reachthe burner).Close the pilot gas valves.Release to modulation (allow modulation of the gas control valve).Above sequence shall be completed to include all required safety checks during the start-up of the burner (process & burnersafeties).Be advised that some regional codes require proving of cross-ignition by sensing flame at both ends of long burners.Flame supervisionStandard connections for flame detection equipment are provided

E - i - 9/15 Duct burners - “NP” & “RG” AIRFLO burner NP-III AIRFLO burners Differential gas pressure at burner inlet For burner capacity 1 MBtu/h/ft Note : For other capacities per foot or gases with different heating values and/