AU662728B2 - Fan unit - Google Patents

Description

AUSTRALIA

Patents Act 1990 662728

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: FAN UNIT 0 00 0 o o 0 4 f0 0 0 0 09 0 o B o eP a 0 0

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0*( The following statement is a full description of this invention, including the best method of performing it known to me: 1^ 0? r 7 j' O?4q2 00 S06 0 00

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-2- "FAN UNIT" This invention relates to a fan unit, and more particularly a fan unit for suspension adjacent the ceiling in a room space being heated, including commercial and industrial spaces, and such is to push warm air accummulating adjacent the ceiling down into the room space to maintain as close as possible to a constant temperature gradient within the room space. Such units serve to reduce the amount of heating necessary to maintain the required comfort temperature within the room space and as a consequence conserves energy and reduces heating costs.

It is known to provide such fan units, but units utilised to date require powerful motor driven fans to achieve the desired result, and the cost of operation of such units reduces the overall heating savings and associated costs.

It is an object of the present invention to provide a fan unit, the efficiency of operation of which is such that transference of heated air downwardly within the room space can be achieved more economically than with known fan units and with which emission of noise is kept to a minimum.

The invention therefore envisages a fan unit for a room space, said fan unit comprising a fan housing, within which a motor driven fan is positioned, and communicating with a nozzle assembly comprising an upper cylindrical section and a lower downwardly and inwardly tapering (Frusto-conical) section from the lower end of which air drawn into the unit by said fan is directed downwardly into il -li 3 an associated room space within which, in use, the unit is suspended, wherein the ratio of the diameter of the cylindrical section to the diameter of the lower end of the tapering section is (1.25 to 1.00) plus or minus 10%, and the ratio of the length of the cylindrical section to the length of the tapered section is 0.88 plus or minus It has been found by extensive and exhaustive testing that fan units constructed to have the above defined ratios of diameters and lengths perform more efficiently with regard to the power required for the motor driven fan and the suppression of air turbulence and associated noise.

One preferred embodiment of the invention will now be described with reference to the accompanying drawing, which is schematic side elevational view of a fan unit in accordance with the preferred embodiment of the present invention.

With reference to the drawing, the fan unit generally indicated as 10, comprises a cylindrical fan housing 11 within which a fan 12, driven by an electric motor 13, is positioned, and which fan unit is attached via connecting flanges 14 to a nozzle assembly 15 to communicate with the interior thereof and force air downwardly S therethrough. The nozzle assembly 15 consists of an upper cylindrical section 16 adjacent the fan housing, a lower downwardly and inwardly tapering (Frusto-conical) section o 17, and a short cylindrical outlet section 18 providing the outlet end of the fan unit.

In this embodiment of the invention the unit, which relates to a relatively large unit for a commercial room space, such as a shop, factory or open office space, has an upper cylindrical section 16 of 358mm in diameter and 176mm in length, the lower tapering section 17 tapers from a diameter of 358mm to a diameter of 305mm, and has a length of 198mm, whilst the outlet section has a diameter of 305mm and a length of 65mm. When associated with an electric driven fan, such as of the type manufactured by Elektroban Mulfingen GmbH and Co. of Geimany, in the order of up to 2950 cubic metres per hour of air transference is produced.

4 Smaller motor driven fans may also be used and the proportions of the nozzle unit should remain the same for best results, that is, a ratio of the diameter of the upper cylindrical section 16 to the diameter of the outlet section 18 being in the order of 1.25 to 1.00 plus or minus 10%, and the ratio of the length of the upper cylindrical section 16 to the length of the tapered section 17 being in the order of 176.00 to 198.00 plus or minus 10%. For a normal sized factory an appropriate unit should be one producing an air f transference of in the order of 1500 cubic metres per hour.

The shaping of the nozzle assembly as described above serves to shape the downward stream of air issuing from the fan so that it leaves the nozzle assembly in the form of a comparatively narrow jet extending down to the floor beneath, which may be up to 14 to 25 metres below, when the fan is suspended in a room space adjacent the ceiling thereof by suspension means (not shown). The two cylindrical sections 16 and 18 of the nozzle assembly serve to reduce turbulence, and thus noise. The sections 16, 17 and 18 may be formed from plastics of 1.00 to 1.50 mm thickness. The external surface of the unit may also be coated with flexible PVC sheeting of 0.75 mm thickness.

Independent and exhaustive tests have been carried out in a controlled environment test room operated by a Government department, involving a comparison of the heating required in the test room with no fan unit operating, with the heating requirements of the same test room when using a fan unit in accordance with the preferred embodiment of the invention operating. The tests showed that with an average room temperature of in the order of 22.0 degrees centigrade Sand an outside ambient temperature of 10 degrees centigrade, 5089 watts of electrical heating power was used over a period of time to maintain the room temperature, whilst with the fan unit operating the electrical heating power required to maintain the same room temperature over the same period of time dropped to 3505 watts, a saving of in the order of 31.2%. The test was repeated with an outside ambient temperature of 5 degrees centigrade and average room temperature of 22 degrees, and a saving of 33.1% resul.ed.

In other tests conducted in the premises of another Government department energy savings averaging 41% after repeated tests have been realised. Energy savings of that order means, particularly in relation to commercial room spaces, that large cost savings in heating the room space can be achieved.

High level of energy savings depend upon several variables which are partly interrelated, such as; 1. the distance of the unit below the ceiling, 2. the ability of the fan to force air to floor level, 3. the rate of air transference, and 4. the dimensions of the cylindrical and tapering sections.

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Claims (4)

1. A fan unit for a room space, said fan unit comprising a fan housing, within which a motor driven fan is i positioned, and communicating with a nozzle assembly comprising an upper cylindrical section and a lower downwardly and inwardly tapering section from the lower end of which air drawn into the unit by said fan is directed downwardly into an associated room space within which, in use, the unit is suspended, wherein the ratio of the diameter of the cylindrical section to the diameter of the lower end of the tapering section is (1.25 to 1.00) plus or minus 10%, and the ratio of the length of the cylindrical section to the length of the tapered section is 0.88 plus or minus

2. A fan unit as claimed in claim 1, wherein a relatively short cylindrical outlet section is also provided at the end of the downwardly and inwardly tapering section to provide an outlet from the fan unit.

3. A fan unit as claimed in claim 1 or 2, wherein means are provided to suspend the fan unit from an overhead structure.

4. A fan unit substantially as hereinbefore described with reference to the accompanying drawing. 0 4 o t DATED THIS 11TH DAY OF JULY 1995 TAYLOR CONSULTANTS PTY. LTD S* By Its Patent Attorneys: 0 0 GRIFFITH HACK CO., Fellows Institute of Patent Attorneys of Australia I i I j ABSTRACT There is disclosed a fan unit (10) for a room space, said fan unit comprising a fan housing within which a motor driven fan (12, 13) is positioned, and communicating with a nozzle assembly (15) comprising an upper cylindrical section (16) and a lower downwardly and inwardly tapering (Frusto-conical) section (17) from the lower end of which air drawn into the unit by said fan is directed downwardly through a short cylindrical outlet section and into an associated room space within which, in use, the unit is suspended. The ratio of the diameter of the cylindrical section to the diameter of the lower end of the tapering section is (1.25 to 1.00) plus or minus 10%, and the ratio of the length of the cylindrical section to the length of the tapering section is 0.88 plus or minus ,o i 0 I ID