GB2177190A - Reducing turbulence in air conditioning ducts - Google Patents

Reducing turbulence in air conditioning ducts Download PDF

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Publication number
GB2177190A
GB2177190A GB08516015A GB8516015A GB2177190A GB 2177190 A GB2177190 A GB 2177190A GB 08516015 A GB08516015 A GB 08516015A GB 8516015 A GB8516015 A GB 8516015A GB 2177190 A GB2177190 A GB 2177190A
Authority
GB
United Kingdom
Prior art keywords
nozzle
sleeve
duct
air
fitting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08516015A
Other versions
GB2177190B (en
GB8516015D0 (en
Inventor
Andrew Ian Claud Black
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LAND SECURITIES
Original Assignee
LAND SECURITIES
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by LAND SECURITIES filed Critical LAND SECURITIES
Priority to GB8516015A priority Critical patent/GB2177190B/en
Publication of GB8516015D0 publication Critical patent/GB8516015D0/en
Publication of GB2177190A publication Critical patent/GB2177190A/en
Application granted granted Critical
Publication of GB2177190B publication Critical patent/GB2177190B/en
Expired legal-status Critical Current

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Classifications

    • 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
    • F24F13/02—Ducting arrangements
    • F24F13/0209—Ducting arrangements characterised by their connecting means, e.g. flanges
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L41/00—Branching pipes; Joining pipes to walls
    • F16L41/08—Joining pipes to walls or pipes, the joined pipe axis being perpendicular to the plane of the wall or to the axis of another pipe
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
    • F16L55/02—Energy absorbers; Noise absorbers
    • 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
    • F24F13/24—Means for preventing or suppressing noise

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Duct Arrangements (AREA)

Abstract

In order to reduce turbulence where air flows merge or separate in a high velocity air duct system, an air duct fitting comprises a nozzle 12 mounted inside a sleeve 14 with space 16 between the outside of the nozzle 12 and the inside of the sleeve 14, so that air flow to or from a branch duct 20, connected to an opening 18 in sleeve 14, flows in the space 16 generally parallel to air flow within the nozzle 12 to or from a main duct 22, with little turbulence where the two air flows merge, or separate, according to their direction. Sound insulating material 40 is provided between the sleeve and the nozzle and nuts 38 allow adjustment of the position of the nozzle. <IMAGE>

Description

SPECIFICATION Air duct fittings This invention relates to air duct fittings.
In certain types of buildings, especially older buildings due for refurbishment, space for air duct systems is severely limited, to the extent that air ducts are required to conduct air at high velocity (that is to say, substantially higher than the normally preferred velocity for an air duct) in order to obtain a sufficient number of air changes per diem (sufficient, that is, by modern standard). One particular problem associated with a high velocity air duct system is turbulence, with consequential noise and pressure loss, where the air flows of two ducts merge or separate, according to direction.
It is believed possible by means of the present invention to provide an air duct fitting which reduces such turbulence, especially in a high velocity air duct system.
According to the present invention there is provided an air duct fitting for use in an air duct system, the fitting comprising a nozzle mounted inside a sleeve with space between the outside of the nozzle and the inside of the sleeve, and an opening in the sleeve so that a first duct can be connected to the sleeve opening to communicate via the said space with a second duct connected to the nozzle, whereby air flow to or from the first duct flows in the said space generally parallel to air flow within the nozzle, with little turbulence where the two air flows merge, or separate, acccrding to their direction.
The invention will be described by way of examples with reference to the accompanying drawings, wherein: Fig. 1 is a diagrammatic side elevation of an air duct fitting embodying the invention; Fig. 2 is another side elevation of the airduct fitting of Fig. 1, at right angles to Fig 1; Fig. 3 is a side elevation of a modification; Fig. 4 is a side elevation of another modification; Fig. 5 is a side elevation of yet another modification; Fig. 6 is a perspective view of the fitting of Figs 1 and 2; and Figs. 7 and 8 are perspective views of two further modifications.
In the various Figures of the drawings, like references refer to like features.
Referring to Figs. 1 and 2, an air duct fitting 10, adapted for use in a high velocity air duct system, comprises a nozzle 12 mounted as shown inside a sleeve 14 with space 16 between the outside of the nozzle 12 and the inside of the sleeve 14. An opening 18 is provided in the sleeve 14, so that a branch duct 20 can be connected to the sleeve opening 18, to communicate via the space 16 with a main duct 22, which is connected to the nozzle 12, and a second main duct 24 which is connected to the sleeve 14 via an annular end cap 26. The nozzle 12, sleeve 14, space 16, opening 18, ducts 20, 22 and 24 and end cap 26 are all preferably of circular crosssection,(or perhaps rectangular cross-section) in order to maximise the efficiency of the air flow.If the fitting 10 is provided in an air extract system, air flows from the branch duct 20 and main duct 22 merge in the fitting 10, to flow into the second main duct 24. On the other hand, if the fitting 10 is part of an air supply system, the air flows into the branch duct 20 and main duct 22, from the second main duct 24, separating in the fitting 10.
The diameter of the branch duct 20 is less than the diameter of the main duct 22, which is the same as, or less than, the diameter of the second main duct 24. The diameter of the nozzle 12 is substantially equal to the diameter of the main duct 22, although not exactly so. The end cap 26 comprises an annular wall 28 which extends between the sleeve 14 and the second main duct 24. In order to minimise turbulence of air flow in either direction between the branch duct 20 and the second main duct 24, the end cap 26 also has a frusto-conical wall 30 which converges from the sleeve 14 towards the second main duct 24 as shown.
A second annular end cap 32 is provided at the other end of sleeve 14 as shown, and the nozzle 12 is slidably mounted in the second end cap 32 so that the position of the nozzle 12 in the fitting 10 can be longitudinally adjusted. Screw-threaded studs 34 are fixed to the nozzle 12 and project through axial slots 36 in the end cap 32 and are fitted with knurled nuts 38 whereby the longitudinal position of the nozzle 12 can be fixed upon tightening the nuts 38.
Sound-insulating material 40 fills an annular space between the outside of the nozzle 12 and the inside of the sleeve 14, between the second end cap 32 and an intermediate annular cap 42 which is fixed to the inside to the sleeve 14, close to the sleeve opening 18, and which slidably fits around the nozzle 12, the intermediate annular cap 42 being perforated for sound-deadening purposes.
In a modification, not shown, a guide ring is substituted for the cap 42. A sufficient number of struts to provide the necessary stiffness fix the guide ring to the sleeve 14.
A front end portion 44 of the nozzle 12 is necked as shown. The axial slots 36 in the second end cap 32 provide a degree of longitudinal adjustment of the position of the nozzle 12, indicated by double-headed arrows 46, and a corresponding degree of adjustment between the front end portion 44 of the nozzle 12 and the narrow end 48 of the frusto-conical wall 30 of annular end cap 26, as indicated by double-headed arrows 50, with a corresponding variation in the width of the space between the front end portion 44 of nozzle 12 and the wall 30, indicated by another double-headed set of arrows 52, which varies the resistance to air flow between the branch duct 20 and the second main duct 24.
Referring to Fig. 3, the fitting is modified by having a linear motor 54, for example, a pneumatic piston-in-cylinder device, mounted to the sleeve 14 and connected to the nozzle 12 by a linkage indicated diagrammatically at 56 for adjusting the longitudinal position of the nozzle 12. The motor 54 may be remotely operated in well-known manner.
Referring to Fig. 4, the first end cap 26a is formed as a venturi tube as shown, having a first frusto-conical wall 30a which converges from the sleeve 14 towards the second main duct 24 and a second frusto-conical wall 30b which converges from the second main duct 24 towards the nozzle 12, the two frustoconical walls 30a and 30b meeting at a neck 30c. It is believed that this formation may improve the efficiency of the air flow and reduce turbulence still further.
Referring to Fig. 6, the first end cap 26b is slightly less necked than the end cap 26a of Fig. 4, and the nozzle 12a is parallelsided except for an annular bulge 62 which restricts the air flow between the branch duct 20 and the second main duct 24 to a variable extent depending upon the longitudinal position of the nozzle Referring to Fig. 7, the branch duct 20a has a frustoconical neck where it is connected to the sleeve 14, so as to smooth the air flow.
In the embodiment of Fig. 8, the branch duct 20b is eccentric to the sleeve 14.
In each of the described and illustrated embodiments, the air flow to or from the branch duct 20 (20a, 20b) flows in the space 16 generally parallel to air flow within the nozzle 12 (12a), at least in the region of the fitting where the two air flows merge, or separate, according to their direction. Because the two air flows (the one to or from the branch duct and the other in the nozzle) are generally parallel where they merge or separate, turbulence is reduced, and hence pressure loss and noise are also reduced.
An important feature of each of the embodiments is the sharp edge 44a (Fig.1) of the front end portion 44 of the nozzle, where the two air flows merge or separate. Various shapes and types of nozzles can be fitted to maximise the efficiency of the fittings. These nozzles may be converging, diverging or straight depending on the precise dimensions of the fittings.
The invention is not limited to the provision of a single branch duct as shown, but one or more further branch ducts (not shown) may be similarly connected to the sleeve in each embodiment.
The above-described and illustrated air duct fittings may be utilised especially in air duct systems of air-conditioning installations.

Claims (9)

1. An air duct fitting for use in an air duct system, the fitting comprising a nozzle mounted inside a sleeve with space between the outside of the nozzle and the inside of the sleeve, and an opening in the sleeve so that a first duct can be connected to the sleeve opening to communicate via the said space with a second duct connected to the nozzle, whereby air flow to or from the first duct flows in the said space generally parallel to air flow within the nozzle, with little turbulence where the two air flows merge, or separate, according to their direction.
2. A fitting as claimed in claim 1 wherein the relative axial positions of the nozzle and sleeve are adjustable.
3. A fitting as claimed in claim 2 wherein variable resistance to the air flow in the first duct is achievable by variation in the geometry of the said space with the variation in the relative positions of the nozzle and sleeve.
4. A fitting as claimed in claim 2 or 3 wherein- a motor is provided for adjusting the said relative axial positions of the nozzle and sleeve.
5. A fitting as claimed in claim 2, 3 or 4 wherein the nozzle is slidably adjustable within the sleeve, which is adapted to be fixed in relation to the two air ducts.
6. A fitting as claimed in any preceding claim wherein soundabsorbing material is provided at a closed end of the sleeve.
7. A high velocity air duct system comprising a fitting as claimed in any preceding claim, a first duct connected to the opening in the sleeve and a second duct connected to the nozzle.
8. A system as claimed in claim 7 wherein the two airflows merge.
9. A system as claimed in claim 7 wherein the two airflows separate.
GB8516015A 1985-06-25 1985-06-25 Air duct fittings Expired GB2177190B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8516015A GB2177190B (en) 1985-06-25 1985-06-25 Air duct fittings

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8516015A GB2177190B (en) 1985-06-25 1985-06-25 Air duct fittings

Publications (3)

Publication Number Publication Date
GB8516015D0 GB8516015D0 (en) 1985-07-31
GB2177190A true GB2177190A (en) 1987-01-14
GB2177190B GB2177190B (en) 1989-07-26

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB8516015A Expired GB2177190B (en) 1985-06-25 1985-06-25 Air duct fittings

Country Status (1)

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GB (1) GB2177190B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0424593A1 (en) * 1989-10-26 1991-05-02 Duruz Sa Fabrique D'articles Metalliques Connector for an extraction system
WO1995005565A1 (en) * 1993-08-13 1995-02-23 Bröderna Rasch Ab Silent regulating valve
FR2867842A1 (en) * 2004-03-16 2005-09-23 Soler Y Palau Sa Ventilation pipe for use in mechanical ventilation case, has tubular unit with inlet and outlet, where diameter of passage from inlet to outlet converges from inlet`s diameter to outlet`s diameter, while convergence being of tube type

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB312213A (en) * 1928-02-22 1929-05-22 Eric Cecil Gordon England Improvements in or relating to ventilators, more especially for closed motor car bodies
GB341460A (en) * 1929-08-06 1931-01-16 Henri Frederic Osmin Sabarthez
GB1168666A (en) * 1967-07-19 1969-10-29 Heinz Hoelter Gas Ejector Units e.g. for Use in the Ventilation of Mine Workings.
US4002110A (en) * 1973-04-02 1977-01-11 Institutal Pentru Creatie Stintifica Si Tehnica Automatic obturator for a gasodynamic ventilation device
US4013217A (en) * 1975-10-31 1977-03-22 Westinghouse Electric Corporation Double induction air conditioning with fluidic control
US4448111A (en) * 1981-01-02 1984-05-15 Doherty Robert Variable venturi, variable volume, air induction input for an air conditioning system

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB851911A (en) * 1956-08-24 1960-10-19 Four Industriel Belge Apparatus for keeping constant the composition of a mixture of air and fuel-gas
GB1311111A (en) * 1970-04-04 1973-03-21 Little P B M Holywell Eng Co Multi-pressure compressed air induction systems for use with low pressure pneumatic stowers in mines
DE2717685C3 (en) * 1977-04-21 1981-04-02 Audi Nsu Auto Union Ag, 7107 Neckarsulm Internal combustion engine for motor vehicles

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB312213A (en) * 1928-02-22 1929-05-22 Eric Cecil Gordon England Improvements in or relating to ventilators, more especially for closed motor car bodies
GB341460A (en) * 1929-08-06 1931-01-16 Henri Frederic Osmin Sabarthez
GB1168666A (en) * 1967-07-19 1969-10-29 Heinz Hoelter Gas Ejector Units e.g. for Use in the Ventilation of Mine Workings.
US4002110A (en) * 1973-04-02 1977-01-11 Institutal Pentru Creatie Stintifica Si Tehnica Automatic obturator for a gasodynamic ventilation device
US4013217A (en) * 1975-10-31 1977-03-22 Westinghouse Electric Corporation Double induction air conditioning with fluidic control
US4448111A (en) * 1981-01-02 1984-05-15 Doherty Robert Variable venturi, variable volume, air induction input for an air conditioning system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WO 80/00724 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0424593A1 (en) * 1989-10-26 1991-05-02 Duruz Sa Fabrique D'articles Metalliques Connector for an extraction system
WO1995005565A1 (en) * 1993-08-13 1995-02-23 Bröderna Rasch Ab Silent regulating valve
FR2867842A1 (en) * 2004-03-16 2005-09-23 Soler Y Palau Sa Ventilation pipe for use in mechanical ventilation case, has tubular unit with inlet and outlet, where diameter of passage from inlet to outlet converges from inlet`s diameter to outlet`s diameter, while convergence being of tube type

Also Published As

Publication number Publication date
GB2177190B (en) 1989-07-26
GB8516015D0 (en) 1985-07-31

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19940625