WO1994011244A1 - Air distributor for ventilation in ships - Google Patents

Abstract

An incoming air distributor for supply of pressurized ventilating air to accommodation areas for passengers and personnel in vessels. The incoming air distributor includes at least one connection piece (10, 11) for incoming air, a damper (15) for control of the incoming air flow, means for control of the air temperature, chamber (16) for mixing the air, and an outflow (24) to said passenger and personnel accommodation area. An air flow passage (21, 28, 29) formed between the mixing chamber (16) and the air outflow (24) is equipped with at least one microphone (25) and at least one loudspeaker (27) for noise control. The microphone and the loudspeaker are connected to a microprocessor-controlled unit (26) for active noise control of the noise that occur in the passage (21, 28, 29).

Description

AIR DISTRIBUTOR FOR VENTILATION IN SHIPS,

TECHNICAL AREA ,_'^' 5 The present invention refers to an incoming air distributor for

• supply of pressurized ventilating air to accommodation areas for passengers and personnel in vessels, including at least one connection piece for incoming air, means for control of the incoming air flow, means for control, of the air temperature,

10 a chamber for mixing the air, and at least one outflow to said passenger and personnel accommodation area.

BACKGROUND OF THE INVENTION

A vessel can move between different climatic zones and is 15 therefore to a great extent dependent on a well functioning ventilating system to maintain a fairly acceptable environment in cabins, mess-rooms, day-rooms and at different working sites.

20 The ventilating system of a modern ship includes incoming air distributors according to above, which according to a known embodiment have several functions. For instance, this known incoming air distributor can be used to produce the climate in the cabin space by mixing hot- and cold air, by

25 dehumidification or humidification of the incoming air, and by additional heating. A number of other functions to be mentioned are mixing and distribution of the preconditioned air, serving as a fire insulating element, and as a suppressor of sound from the fan- and ventilation system.

30

This incoming air distributor must not be more voluminous than

• it can be built into a limited space between a ceiling and a^■ deck situated just above. The demands for limited installation dimensions make it at the same time difficult to meet the

35 demands for good insulation between the incoming flows of cold- and hot air, insulation against fire, and sound insulation.

The normal installation of the incoming air distributor at the centre of a cabin's ceiling ensures a maximum air distribution, but the sound transmitted to the cabin via the incoming air distributor is regarded as relatively disturbing. Great efforts is yet done to minimize the noise when planning ventilation systems and designing incoming air distributors.

Active noise control has been known for many years and is described in the patent literature, for example in US 2043416. The method has got many different uses. For instance active noise control has been used for suppression of noise in ventilation ducts, whereby the elementary noise has been generated by an axial fan. One example of active noise control at a radial fan is described in GP 2117046. This known device is designed to suppress the local pressure pulses produced by the rotor blades as they pass the outflow rim of the fan. The device is consequently not adapted for suppression of non- structured broad-band-, so-called, random noise.

However, so far, any practical solution of applying a broa - band-, active noise control on incoming air distributors for passenger and personnel accommodations in vessels is not known.

THE TECHNICAL PROBLEM The purpose of the present invention is therefor to achieve a incoming air distributor with active noise control for that special use.

THE SOLUTION For this purpose, the incoming air distributor according to the invention is characterized in an air flow passage formed between the mixing chamber and the air outflow, which passage is equipped with loudspeakers and at least one microphone at its upstream end, and/or at its downstream end, which are connected to a microprocessor-controlled unit for active control of the noise that occur in the passage. DESCRIPTION OF THE DRAWINGS t The invention will now be described herebelow with reference

5 to the embodiments that are shown in the enclosed drawings, . where:

Fig. 1 shows an incoming air distributor according to the invention in a plane view, Fig. 2 is a section along the line II-II in Fig. 1,

10 and

Fig. 3 shows an alternative embodiment of the incoming air distributor.

DESCRIPTION OF EMBODIMENT 15 The incoming air distributor in Fig. 1 and 2 is in broad outline formed as a flat box with a lid, bottom and four side-walls, where all wall-elements suitably are heat- and fire-insulated.

20 In Fig. 1 reference numeral 10 indicates an incoming air duct for cold air and numeral 11 an incoming air duct for hot air, where both ducts feeds the incoming air distributor with fresh air. Both the ducts 10, 11 emerge into slit orifices 12 and 13 for the cold and hot air respectively. The ratio of mixture

25 between cold and hot air is adjustable by a motor 14 that is connected to the damper lever 15.

The lever 15 regulates both air flows separately into a mixing chamber 16, where the mixing of the air occurs. The mixing

30 chamber 16 is separated from the remaining parts of the incoming air distributor by means of a horizontal partition wall 17. The outflow openings 18 from the mixing chamber are arranged between the slit orifices 12, 13 and lead the air from

. an upper story to a lower story in the incoming air

35 distributor. A vertical transverse wall 19 ducts the air in the lower story further around an angle that is produced by a vertical partition wall 20 which together with the partition wall 17 defines a passage 21 for the air inside the incoming air distributor.

The passage 21 emerges through an opening 22 to an outflow chamber 23. This chamber 23 is in its turn fitted with a downward directed outflow opening 24 to which is connected an outflow in the cabin ceiling.

The passage 21 is fitted with a microphone 25 at its upstream end, which microphone is connected to a phase changing and amplitude adjusting amplifier unit 26. The unit 26 is in its turn connected to a loudspeaker 27 located at the downstream end of the passage.

The microphone 25 registers both that noise which is transmitted to the incoming air distributor via the ducts 10, 11, and from fans and flow directing means, and that noise which is created inside the incoming air distributor. These noises are preferably of a low frequency sort and is well adapted for active noise control. Noise from higher frequencies are damped to a large extent by the heat- and fire insulation of the incoming air distributor. The air treatment components in the incoming air distributor, such as damper, radiator etc. are preferably designed so that the noise which needs to be damped principally contains noise with low and high frequencies, for.example. frequencies up to 1000 Hz and frequencies above 4000 Hz.

Fig. 3 shows a variant of the invention where the passage 21 and the mixing chamber 23 are integrated to a elongated, flattened tube 28, which emerges into a downward directed diffuser 29. The diffuser is fitted with a screen 30 which is formed so that the air flow is directed outward along the underside of the ceiling boarding. The microphone 25 is placed at one end of the tube 28, while the loudspeaker 27 is placed between the end of the tube 28 and the diffuser 29. A second microphone 32 is placed by the outflow of the diffuser and is used for detection of any faults in the noise extinction.

The invention is not limited to the above described embodiments, instead more variants are conceivable within the scoop of following claims. For instance the incoming air distributor does not need to be fitted with connections for hot air, but can instead include means for heating of the air. The passage 21 can be developed differently than shown.

Claims

1. An incoming air distributor for supply of pressurized ventilating air to accommodation areas for passengers and personnel in vessels, including at least one connection piece (10, 11) for incoming air, means (15) for control of the incoming air flow, means for control of the air temperature, chamber (16) for mixing the air, and at least one outflow (24) to said passenger and personnel accommodation area, c h a r a c t e r i z e d i n, an air flow passage (21, 28, 29) formed between the mixing chamber (16) and the air outflow (24), which passage is equipped with a loudspeaker (27) and at least one microphone (25) at its upstream end and/or at its downstream end, which are connected to a microprocessor-controlled unit (26) for active control of the noise that occur in the passage (21, 28, 29).

2. An incoming air distributor according to claim 1, c h a r a c t e r i z e d i n, that the passage (21) runs between the mixing chamber (16) and a outflow chamber (23) .

3. An incoming air distributor according to claim 2, c h a r a c t e r i z e d i n, that the mixing chamber (16) and the outflow chamber (23) are accommodated in a room covered with sound- and fire insulating material.

4. An incoming air distributor according to any of preceding claims, c h a r a c t e r i z e d i n, that the means for controlling the temperature of incoming air include mixing valves for incoming hot and cold air.

5. An incoming air distributor according to claim 4, c h a r a c t e r i z e d i n, that the means for controlling the temperature of incoming air include a radiator.

6. An incoming air distributor according to any of preceding claims, c h a r a c t e r i z e d i n, that inner channels, damper lever, radiator etc. is designed in such a way that the noise created of the air flow primarily contains low- and high frequency sound waves.

7. An incoming air distributor according to claim 1, at which the microphone (25) is placed upstream in relation to the loudspeaker (27), c h a r a c t e r i z e d i n, that one additional microphone (32) is placed downstream the loudspeaker (27), for adaptive compensation of faults in the active noise control.