US2976794A - High-velocity primary air nozzle - Google Patents

High-velocity primary air nozzle Download PDF

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Publication number
US2976794A
US2976794A US731045A US73104558A US2976794A US 2976794 A US2976794 A US 2976794A US 731045 A US731045 A US 731045A US 73104558 A US73104558 A US 73104558A US 2976794 A US2976794 A US 2976794A
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United States
Prior art keywords
primary air
air
flow
velocity
primary
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Expired - Lifetime
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US731045A
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English (en)
Inventor
Allander Claes
Larkfeldt Birger
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Svenska Flaktfabriken AB
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Svenska Flaktfabriken AB
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
    • F24F1/01—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station in which secondary air is induced by injector action of the primary air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D5/00—Hot-air central heating systems; Exhaust gas central heating systems
    • F24D5/02—Hot-air central heating systems; Exhaust gas central heating systems operating with discharge of hot air into the space or area to be heated
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
    • F24F13/26—Arrangements for air-circulation by means of induction, e.g. by fluid coupling or thermal effect

Definitions

  • the present invention relates to a device for inducing and mixing by ejecting action secondary air into a current of primary air-discharged from a duct or pressure chamber, said device consisting of nozzle means connected to said duct or chamber.
  • Devices of this kind are nowadays used for ventilating plants in order to create a circulation of the room air by means of a limited preferably pre-treated quantity of air supplied to said room. It can be made evident both theoretically and experimentally, that when a resistance is present for the flow of the mixture, the quantity of secondary air increases with increasing velocity of the discharged primary air and with an increased value of the total boundary lines of the primary-air jets. Since in actual practice it is desired to have a heavy ejection of room air and an intimate mixing between primary and secondary air, it will be necessary to work with as high a discharge velocity as possible and with as large a value of the total boundary lines of the primary air jets as possible.
  • noise occurs.
  • apparatus of the kind used within the ventilating technique-to which the present invention relatesthere is an extraordinary requirement for freedom from noise.
  • the noise occurs usually because of whirling currents and increases with the extent of whirls and these usually arise in the nozzles or flow passages constituting the discharge means for the primary air.
  • the deciding factor for the degree of the occurrence of whirls in a flow passage for a medium is the actual Reynolds number for the flow. This number is defined as the product of the how velocity of the medium and the hydraulic diameter of said flow passage divided by the kinetic viscosity of the flowing medium.
  • a shifting from laminar to turbulent flow occurs at a value of the Reynolds number of about 2000.
  • the value decreases depending upon disturbances in the inlet of said passage.
  • the rule may thus be so formulated that for a constant pressure reduction, the noise increases with increasing Reynolds number, and thus a method to satisfy the requirement for noise elimination is to work with small Reynolds numbers.
  • the length of the passage In order to obtain the necessary throttling or pressure reduction, the length of the passage must increase with a decrease in the Reynolds number and thus the length of said flow passage in accordance with the invention should considerably exceed the hydraulic diameter of same.
  • the device according to the invention is constructed in accordance with the above mentioned principles, and is characterized in that the primary air nozzle means is provided with a great number of narrow slots arranged mutually parallel and adjacent each other.
  • the slots constitute throats of a corresponding number of passages having substantially the same cross-section area as 5' nited States Patent 0 said slots and being so dimensioned with respect to their length as well as their cross-section area that the flow through said passages takes place without any obvious occurrence of whirls.
  • the nozzle means should preferably be made with a relatively small width in relation to the length of same and the flow passages should be arranged substantially perpendicular to the longitudinal direction of the nozzle means.
  • the flow passages should be given such a hydraulic diameter that the Reynolds number does not exceed 2000.
  • the nozzle means should be made of a soft, sound-deadening material for instance of rubber, plastic material or the like.
  • Fig. 2 is a cross-section along the line 2-2 of Fig. 1.'
  • Fig. 3 is an elevational View in a larger scale with portions broken away illustrating the nozzle means applied to a duct.
  • Fig. 4 is an enlarged cross-section along the line 44 of Fig. 3 and Fig. 5 is a horizontal plan view of the duct of Fig. 3.
  • a nozzle means 1 in accordance with the invention is mounted in a ventilating unit 3 and is connected to a duct 2, supplying said unit with ventilating air (primary air).
  • the unit in the illustrated embodiment of the invention is provided with a conventional heat exchanger 4 for finally heating the air, inlet openings 6, 7 for secondary air and a discharge opening 5 for the mixture of primary and secondary air.
  • the location of said openings 6 and 7 may be varied in accordance with the placing of the unit. It is essential that the room air introduced through said openings is conducted in such a way that the room air will be supplied adjacent the nozzle means as shown by the arrows in Fig. 2.
  • the nozzle means 1 comprises a generally rectangular hollow frame with a relatively small width B in relation to its length L and provided with a great number of spaced parallel narrow partitions disposed transversely of said frame across its full width and defining a like number of narrow mutually parallel slots 8 arranged adjacent each other. Said slots constitute the throats of a corresponding number of flow passages 9 having substantially the same cross-sectional area as said slots.
  • the flow passages are connected at their inner ends to the conduit or duct 2 and are of uniform cross section throughout. At their outer ends, the flow passages terminate in spaced parallel outlet openings or slots which create a like number of flat streams of primary air flowing into the unit 3.
  • the depth of the frame and partitions should be substantially greater than the hydraulic diameter of the flow passages to reduce the effect of disturbances at the inlet to the flow passages.
  • the discharge slots 8 should, as in the illustrated embodi- 3 Es i ment be arranged substantially perpendicular to the length direction of the nozzle means in order to secure as large an area of introduction for the secondary air as possible.
  • the flow passages 9 are located-res shown in Fig. --with a suitable spacing with respect to their width X.
  • an air conditioning room unit having a conduit for the supply of high-velocity primary air, means to admit secondary room air into said unit, and means to exhaust a mixture of primary and secondary air from said unit; an elongated nozzle element within said unit comprising a generally rectangular hollow frame connected at its inner end to the conduit and having a substantially plane outer surface, and a plurality of spaced parallel narrow partitions disposed transversely of said frame across its full width and coextensive in depth with said frame, said partitions defining'a plurality of transverse spaced parallel narrow flow-passages connected at their inner ends to said conduit, extending through said frame with uniform cross section throughout and terminating at their outer end in a like number of spaced parallel outlet openings creating a like number of fiat streams 'of primary air flowing into said unit, said partitions creating cavities of sub-atmospheric pressure between said streams into which the secondary air is drawn and mixed with said primary air, the partitions being spaced apart relative to the width of said hollow frame to pro quiz in said passages a hydraulic diameter
  • a device according to claim 1 wherein the nozzle element is relatively small in width in relation to its length and that the flow passages are arranged substanperpendicular to the longitudinal direction of said nozzle means.
  • a device according to claim 1 wherein said primary air conduit extends through said unit and said nozzle element is disposed longitudinally of said conduit whereby said narrow flow passages are disposed transversely of the primary air flow in said conduit.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Duct Arrangements (AREA)
  • Jet Pumps And Other Pumps (AREA)
US731045A 1957-04-30 1958-04-25 High-velocity primary air nozzle Expired - Lifetime US2976794A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE2976794X 1957-04-30

Publications (1)

Publication Number Publication Date
US2976794A true US2976794A (en) 1961-03-28

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ID=20428049

Family Applications (1)

Application Number Title Priority Date Filing Date
US731045A Expired - Lifetime US2976794A (en) 1957-04-30 1958-04-25 High-velocity primary air nozzle

Country Status (6)

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US (1) US2976794A (no)
BE (1) BE567264A (no)
CH (1) CH361649A (no)
DE (1) DE1194116B (no)
FR (1) FR1195504A (no)
GB (1) GB839798A (no)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3116881A (en) * 1961-12-01 1964-01-07 Bauknecht Gmbh G Dish-washer nozzle assembly
US3203337A (en) * 1961-02-27 1965-08-31 Dual Jet Refrigeration Company Refrigerated display case and elements thereof
US3434522A (en) * 1966-09-21 1969-03-25 Francois Laurenty Spray type flash evaporator
US3528614A (en) * 1967-05-13 1970-09-15 Ltg Lufttechnische Gmbh Fluid admixing apparatus
US3584786A (en) * 1968-12-30 1971-06-15 Patent And Dev Of North Caroli Fluid dispersion nozzle
FR2229023A1 (no) * 1973-05-07 1974-12-06 Svenska Flaektfabriken Ab
US3895567A (en) * 1972-08-30 1975-07-22 Werner Paul Air outlet arrangement for air conditioning and ventilating apparatus
US7013969B1 (en) * 2004-07-09 2006-03-21 Loudermilk Kenneth J Low noise level HVAC system having displacement with induction
US20120273070A1 (en) * 2011-04-28 2012-11-01 Freers James L Optimized air delivery apparatus
US20150336057A1 (en) * 2012-11-14 2015-11-26 General Electric Company Open bottom multiple channel gas delivery device for immersed membranes
US9557108B2 (en) 2011-04-28 2017-01-31 Maxum Llc Low profile air delivery apparatus with interchangeable nozzle inserts

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2922441C2 (de) * 1979-06-01 1985-10-17 Heinrich Dipl.-Ing. 5205 St Augustin Hilbers Induktionsgerät zur Belüftung von Aufenthaltsräumen

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1463263A (en) * 1922-09-23 1923-07-31 John H Grayson Burner tip
US2161027A (en) * 1936-04-14 1939-06-06 Staynew Filter Corp Fan
US2210023A (en) * 1940-08-06 Grille
GB530178A (en) * 1939-06-20 1940-12-06 Carrier Engineering Co Ltd Improvements in or relating to ventilating systems
US2731104A (en) * 1953-10-08 1956-01-17 Gen Motors Corp Air grille
US2737875A (en) * 1951-07-23 1956-03-13 Anemostat Corp America Air outlet device for ventilating apparatus
US2775188A (en) * 1952-11-19 1956-12-25 Russell R Gannon Means for heating and ventilating rooms, particularly school rooms and the like
FR1140710A (fr) * 1955-02-03 1957-08-12 Erik Larsson Goesta Dispositif à convection
US2835187A (en) * 1953-12-02 1958-05-20 Gen Motors Corp Air grill for refrigerating apparatus
US2872859A (en) * 1954-03-02 1959-02-10 Barber Colman Co Air distribution unit

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE884688C (de) * 1940-09-06 1953-07-30 Teves Kg Alfred Luftauslassmundstueck an Luftkanaelen von Klimaanlagen
US2783979A (en) * 1955-03-02 1957-03-05 Borg Warner Induction unit for air conditioning

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2210023A (en) * 1940-08-06 Grille
US1463263A (en) * 1922-09-23 1923-07-31 John H Grayson Burner tip
US2161027A (en) * 1936-04-14 1939-06-06 Staynew Filter Corp Fan
GB530178A (en) * 1939-06-20 1940-12-06 Carrier Engineering Co Ltd Improvements in or relating to ventilating systems
US2737875A (en) * 1951-07-23 1956-03-13 Anemostat Corp America Air outlet device for ventilating apparatus
US2775188A (en) * 1952-11-19 1956-12-25 Russell R Gannon Means for heating and ventilating rooms, particularly school rooms and the like
US2731104A (en) * 1953-10-08 1956-01-17 Gen Motors Corp Air grille
US2835187A (en) * 1953-12-02 1958-05-20 Gen Motors Corp Air grill for refrigerating apparatus
US2872859A (en) * 1954-03-02 1959-02-10 Barber Colman Co Air distribution unit
FR1140710A (fr) * 1955-02-03 1957-08-12 Erik Larsson Goesta Dispositif à convection

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3203337A (en) * 1961-02-27 1965-08-31 Dual Jet Refrigeration Company Refrigerated display case and elements thereof
US3116881A (en) * 1961-12-01 1964-01-07 Bauknecht Gmbh G Dish-washer nozzle assembly
US3434522A (en) * 1966-09-21 1969-03-25 Francois Laurenty Spray type flash evaporator
US3528614A (en) * 1967-05-13 1970-09-15 Ltg Lufttechnische Gmbh Fluid admixing apparatus
US3584786A (en) * 1968-12-30 1971-06-15 Patent And Dev Of North Caroli Fluid dispersion nozzle
US3895567A (en) * 1972-08-30 1975-07-22 Werner Paul Air outlet arrangement for air conditioning and ventilating apparatus
FR2229023A1 (no) * 1973-05-07 1974-12-06 Svenska Flaektfabriken Ab
US7013969B1 (en) * 2004-07-09 2006-03-21 Loudermilk Kenneth J Low noise level HVAC system having displacement with induction
US20120273070A1 (en) * 2011-04-28 2012-11-01 Freers James L Optimized air delivery apparatus
US8814067B2 (en) * 2011-04-28 2014-08-26 Maxum Llc Optimized air delivery apparatus
US9551529B2 (en) 2011-04-28 2017-01-24 Maxum Llc Air delivery apparatus with interchangeable nozzle inserts
US9557108B2 (en) 2011-04-28 2017-01-31 Maxum Llc Low profile air delivery apparatus with interchangeable nozzle inserts
US20150336057A1 (en) * 2012-11-14 2015-11-26 General Electric Company Open bottom multiple channel gas delivery device for immersed membranes
US10702829B2 (en) * 2012-11-14 2020-07-07 Bl Technologies, Inc. Open bottom multiple channel gas delivery device for immersed membranes

Also Published As

Publication number Publication date
CH361649A (de) 1962-04-30
BE567264A (no)
FR1195504A (fr) 1959-11-18
GB839798A (en) 1960-06-29
DE1194116B (de) 1965-06-03

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