US 3881402 A
A method for ventilating spacious public rooms, workshops, industrial halls and the like spaces wherein ventilating medium is supplied in large quantity at low velocity and is circulated within the space by high-velocity jets positioned in series and preferably adjustable to circulate the ventilating medium into the areas of the space which require ventilation. The jets inject only a small quantity of medium which may be separately conditioned or fed from a separate supply. The method is particularly effective for obtaining a desirable circulation of the ventilating medium in areas which are partially screened from main supply by a column or other barrier.
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Description (OCR text may contain errors)
[ May 6,1975
[ DISTRIBUTING VENTILATING MEDIUM WITHIN SPACES  Inventor: Birger Liirkfeldt,Odensjo'Barnarp,
Sweden  Assignee: Aktiebolaget Svenska Flaktfabriken,
Nacka, Sweden  Filed: May 4, 1973  Appl. No.2 357,252
 References Cited UNITED STATES PATENTS 8/1931 Carson 98/39 X 10/l972 Larkfeldt 98/40 D FOREIGN PATENTS OR APPLICATIONS 8/1936 United Kingdom 98/40 R Primary Examiner-Carroll B. Dority, .lr. Assistant Examiner-Peter D. Ferguson Attorney, Agent, or FirmDorfman, Herrell and Skillman  ABSTRACT A method for ventilating spacious public rooms, workshops, industrial halls and the like spaces wherein ventilating medium is supplied in large quantity at low ve locity and is circulated within the space by highvelocity jets positioned in series and preferably adjustable to circulate the ventilating medium into the areas of the space which require ventilation. The jets inject only a small quantity of medium which may be separately conditioned or fed from a separate supply. The method is particularly effective for obtaining a desirable circulation of the ventilating medium in areas which are partially screened from main supply by a column or other barrier.
9 Claims, 5 Drawing Figures DISTRIBUTING VENTILATING MEDIUM WITHIN SPACES This invention relates to a method at installations for the ventilation of rooms or of plants for an industrial process, at which air or another gaseous medium is conveyed to and from and, respectively, in and also distributed within said rooms.
The request of installing on a building site ventilation systems with a small investment of labour and in a short time has in recent years increased substantially. The deviation from the conventional building methods which has become evident to an ever increasing extent in structural engineering, particularly for office landscapes, bank premises, sports-halls and other large spaces, also implies a strong request for a flexible ventilation system adjustable to spaces of irregular shape. It was found in many cases that the increasing demands of today and tomorrow on ventilation with respect to effectiveness, flexibilty and inexpensiveness cannot be solved by conventional ventilation systems without the addition of special arrangements, which often are expensive. At present, rooms having a depth of m or more are not unusual any longer. In difficult cases the ventilation of these rooms has been possible only by means of separate special installations. This has involved high initial costs and has often made necessary tedious changes of the building structure. Difficulties of a similar kind arise in many cases of industrial ventilation as well as at the ventilation of cargo spaces on ships, particularly when the cargo is sensitive foodstuffs. It has also become usual to an increasing extent to complete old rooms with better and more complete ventilation. The realization thereof, however, often is very expensive, tedious and difficult. All these disadvantages and difficulties, moreover, have to be added with the increasing demands with respect to maximum temperature gradient and air speed, radiation exchange etc., which by standardization have begun to constitute definite requests for dwelling zones in a room.
The invention implies an entirely new approach to ventilation engineering and has as its object to eliminate the aforesaid disadvantages and difficulties at ventilation installations of conventional design.
The invention as a method is characterized in that the room air and/or supplied ventilation air is caused to move in the desired direction and is distributed in the room(s) by means of one or more ejectors known per se and driven by air or another gaseous medium, that the ejectors are so disposed and dimensioned relative one another that the ejector air flow always is small in relation to the flow of the total conveyed and distributed air or gas amount stabilized by the ejectors(s), and so that the flow within the action range for one or more ejectors always forms a number of controlled, preferably closed paths.
A modification of this method intended for conveyance and distribution of air in dwelling zones of rooms is characterized in that one or more ejectors are so dimensioned and located at such distances relative to and one after the other, that the ventilation air supplied to the rooms, possibly with different conditions, is con veyed, possibly mixed, and distributed in an extent prescribed between the different parts of the dwelling zone(s).
A further modification of this method intended for conveyance and distribution of air, preferably in storeintended for ventilation of spaces of difficult access by i conventional ventilation engineering, for example spaces screened off by projecting parts of irregularly shaped rooms, is characterized in that one or more ejectors are mounted so as to deflect and distribute the entire ventilation air flow or a part thereof, so that zones intended to be dwelling zones in said irregularly shaped rooms are ventilated to the extent desired.
A special embodiment of the arrangement for eliminating an unstable turbulent flow formation, for example behind columns in the rooms(s), which disturbs the conveyance and distribution of the ventilation air, is characterized in that one or more ejectors are located behind the column(s), in the flow direction, concealed by the column and adapted to redirect and straighten said turbulent flows and thereby to reestablish the stable flow prevailing before the column.
A further embodiment of the arrangement is characterized in that the air and/or gaseous medium are adapted to be conveyed and/or distributed by both ejectors and conventional means, for example fans and ducts.
A preferred embodiment of the arrangement for protecting dwelling zones against undesirable thermal air streams or undesirable radiation, for example sudden temperature drops at windows, is characterized in that one or more ejectors are located so as to redirect said thermal air streams away from said dwelling zones.
The ejectors comprised in the arrangement may be constructed for manual or automatic adjustment in optional direction, possibly adjustable in a definite sequence, and/or provided with a manually or automatically variable outlet aperture, and the ejectors may be connected either to a separate air supply unit or to a conventional conveying system for the ventilation air.
An embodiment of the arrangement adapted for ventilation of zones in rooms or in free air, for example working places near objects producing poison gas, is characterized in that it comprises a series of ejectors for directing fresh air from a fresh air magazine through said working place.
An expedient embodiment of the arrangement adapted for ventilation of zones in free air, for example for removing fog from runways on airfields, is characterized in that the ejectors are arranged along the runways for conveying and distributing fog-dissolving gas from a ramp transverse across the runways.
The invention is described in greater detail in the following, with reference to the accompanying drawings, which show by way of example some embodiments of installations in which the method according to the invention has been applied, and the flow at the method according to the present invention compared with the flow at two conventional types of air supply.
FIG. 1 shows in a schematic way an installation, in which the method according to the invention is applied and where no ventilation air is introduced into the room.
FIG. 2 shows in a schematic way a corresponding installation where ventilation air is introduced through a ceiling spreader,
FIG. 3 shows in a schematic way the application of the invention at a room of irregular shape where the ventilation air is supplied through a grate in a short wall,
FIG. 4 shows by way of example an embodiment of an ejector comprised in the installation.
FIG. 5 illustrates schematically the flow when an ejector is located behind a column,
In the drawings, 1 designates a room to be ventilated. The room may have regular or irregular shape and optional dimensions as regards length, width, depth and ceiling height. The room may be a sports-hall, a socalled office landscape or an industrial premise or a similar space, preferably a space which cannot or only with difficulty be ventilated by conventional ventilation engineering at reasonable costs. 2 designates one or more ejectors driven by air or another gaseous medium from an air supply unit 3 indicated schematically in the drawing. 4 and 5 designate connecting conduits connected either to said air supply unit 3 or to a conventional conveying system for the ventilation air 3a. The connecting conduits may be manufactured of plastics or another easily flexible material, which facilitates the installation in rooms of irregular shape. In FIG. 3 the ventilation air is supplied by means of a grate 6 mounted in a wall of the room. According to the invention the ventilation air, however, may be supplied in any optional way, for example as in FIG. 2 by means of a ceiling spreader of conventional design 7. The ventilation air may also be supplied from a fresh air magazine formed as a subceiling in a passage, from which magazine the rooms located on both sides of the passage can be ventilated, irrespective of their varying size and shape. In that case one or more ejectors are to be provided in said fresh air magazine for conveying the air to one or several apertures opening into the rooms(s). Several ejectors may coact in the aperture(s) at the supply in order to mix ventilation air of different conditions from two separate magazines or two separate ducts for different media. The ejectors 2 may be so dimensioned and located at such distances relative each other that the vantilation air thereby is distributed in the room(s) in the extent prescribed between the different parts. of the dwelling zone(s). As shown in FIG. 4, the ejector is presupposed to be rotatable at its upper end 2a about its longitudinal axis for rotation through one revolution, as indicated by the circle are 8. The ejector is hinged at 2b so that its lower end 2c can be caused to change its position along the arc line 10. 9 designates a turnscrew intended for manual adjustment of the outlet aperture of the ejector. The ejector has been described here as being adjustable by hand and having a manually adjustable outlet aperture, but it may as well be designed to automatically change its setting or adjusting its outlet aperture, for example in response to a program control device. It also is possible to control a number of coacting ejectors relative one another in a definite sequence. FIG. 3 shows a type of installation where the ejector is utilized so to deflect and distribute the ventilation flow that it is caused to enter and ventilate a partially screened-off space lb which constitutes a small part of the room la. In a similar way the ejectors may be placed behind, for example, a column in order to redirect and/or straighten such unstable turbulent flows which otherwise would develop and disturb the conveyance and distribution of the ventilation air. For protecting dwelling zones against undesirable thermal air flows or undesirable radiation, the ejectors may also be placed so in the room(s) that they redirect such a flow away from the dwelling zone(s).
In the following, the theoretical background of the invention is explained. The air movement in the dwelling zone depends on the factors as follows:
a. supply air conditions: supply air impulse, supply air temperature in relation to room temperature b. dimensions and shape of the room c. equipment of the room d. location of the supply air device and direction of the supply air e. thermal disturbances (temporary heat loadsexternal circumstances) In a room supplied with ventilation air, in order to effeet the ventilation of the dwelling zone, a certain impulse per unit of length always is required. This necessary supply air impulse may be in conflict with the per missible speed in the dwelling zone. By supplying the ventilation air with an impulse by an ejector, it is possible by selecting the number, size and direction of the ejector type to obtain a ventilation jet which always reaches to the inner wall. The ejector may be so dimensioned that the ejector flow is small in relation to the primary air flow.
The ejector co-ejects the air about the central line of the ventilation jet. If the ejector is assumed to co-eject the ventilation jet up to a given distance from the central line, then about half the flow of the ventilation jet is co-ejected. The remaining part of the ventilation air diffuses out into the room.
By equations it is possible to dimension the ejector for any room depth.
The resulting jet width is substantially constant.
At a complicated shape of the room, as in FIG. 3, it is always difficult to ventilate such parts which are located screened off by projecting corners or by columns. The ejector provides in such cases an excellent possibility of impulsing and directing the ventilation air into the unventilated room part. See FIG. 5.
With the help of equations the ejector can be dimensioned for any supply air flow and any room.
Corresponding equations can be formed for studying the utilization of the ejector for redirecting and straightening the disturbing unstable turbulent flow formations which may develop, for example, behind columns.
By forming equations for impulse balance and heat balance it is possible in a corresponding way to study the applicability of the ejector for the protection of dwelling zones against undesirable air flows, for example sudden temperature drops at windows.
1. A method for ventilating spacious public rooms, workshop spaces, industrial halls, and like spaces, in which the ventilating medium within the space is conveyed and distributed to selected areas within the space; comprising the steps of supplying ventilating medium in the required amount at low velocity, directing the ventilating medium into a controlled circulating path by means of a plurality of ejectors positioned in said path; supplying each ejector with medium to emit a jet of high velocity, the amount of which high velocity medium is small with respect to the ventilating medium; and locating said ejectors within said space in said circulating path in a series so that the second ejector of the series is disposed within the action range of the first ejector in the series.
2. A method according to claim 1 in which the space has a restricted dwelling zone in one part of the space and another zone in another part of the space, and wherein said circulating path for the ventilating medium is located by said ejectors within said dwelling zone in said one part of the space and outside of the other zone of the space.
3. A method for ventilating spacious public rooms, workshop spaces, industrial halls, and like spaces, in which the ventilating medium within the space is conveyed and distributed to selected areas within the space; comprising the steps of supplying fresh ventilating medium to said space in an amount corresponding to the requirement of the space at low velocity, directing the ventilating air into a controlled circulating path by means of a plurality of ejectors positioned in said path such that the fresh ventilating medium flows into said circulating path; and supplying each ejector with medium to emit a jet of medium at high velocity, the amount of which medium is small with respect to the amount ventilating medium, but the velocity of which is high enough to provide an impulse entraining said low-velocity medium and directing it in a controlled flow.
4. A method according to claim 3 including the step of separately supplying air to said ejectors for said jets, and separately conditioning said supplied air.
5. A method according to claim 4 including the step of separately conditioning the fresh ventilating medium prior to supplying it to said space.
6. A method for ventilating a space wherein said space has partial barriers therein partially screening off a portion of said space, in which the ventilating air within the space is conveyed and distributed to selected areas within the space; comprising the steps of direct ing the ventilating air into a controlled circulating path by means of a plurality of ejectors positioned in said path; supplying each ejector with air to emit a jet of air at high velocity, the amount of which air is small with respect to the ventilating air; and locating said ejectors within said space in said circulating path in a series so that the second ejector of the series is disposed within the action range of the first ejector in the series, including the step of supplying fresh ventilating medium to said space at one side of said partial barriers and positioning said ejectors at the other side of said partial barriers to provide a circulating path which deflects and distributes the ventilating medium in the screened-off portion.
7. A method for ventilating a space in which the ventilating air within the space is conveyed and distributed to selected areas within the space; comprising the steps of directing the ventilating air into a controlled circulating path by means of a plurality of ejectors positioned in said path; supplying each ejector with air to emit a jet of air at high velocity, the amount of which air is small with respect to the ventilating air; and locating said ejectors within said space in said circulating path in a series so that the second ejector of the series is disposed within the action range of the first ejector in the series, including the step of adjusting the positions of the ejectors during the ventilating operation to change the velocity of the jet and thereby alter the circulating path created thereby.
8. A space adapted to being ventilated including means defining the boundaries of the space to be ventilated, means to admit ventilating medium into said space, and a series of ejectors mounted in said space at spaced intervals and each positioned to direct a jet of air having a high velocity of a given direction and a small quantity relative to the ventilating medium, said jets operable to create a circulating flow path of the ventilating medium in said space, said ejectors being adjustable to vary the velocity of the jet both by changing the direction of the jet and by varying the quantity flow therefrom.
9. A space according to claim 8 wherein said means to introduce ventilating medium into said space comprises a supply grill adjacent said boundary means and operable to inject ventilating medium into the space so as to flow into said circulating path.
7 Patent No.
CERTIFICATE OF CORRECTION Dated May 1975 Inventofls) Birger. L rkfelcdli It is certified that error appears in the above-identified patent and that said Letters Patent 'are hereby corrected as shown below:
In the Drawings, the figure as shown below should be added:
[SEAL] Qignccl and Scaled this,
fourth Day of Noverfibe r 1 975 AIMS:
RUTH C. MASON C. MARSHALL DANN Alluring Officer (ommissiuneroj'Parems and Trademarks FORM PO-105O (10-69) UNITED STATES PATENT OFFICE CETIFICATE OF CORRECTION Patent No. 3,881,402 D d May 6, 1975 I t Birger Larkfeldt It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
In the heading before  U.S. Cl. the following should be added: Q
 Foreign Application Priority Data May 8, 1972 I Sweden 6071/72 Signed and Scaled this second Day 0f September 1975 [SEAL] Arrest:
RUTH C. MASON Arresting Officer USCOMM-DC 60376-P69 v u.s. covsnuusm FRINTlNG OFFICE: 1959 0-366-334.