Technical field of the invention
[0001] The present invention relates to an innovative micro-perforated channel for air distribution,
having antibacterial features.
Background art
[0002] The quality of the conditioned air conveyed in rooms is nowadays an aspect of primary
importance in the choice of clients, designers and installers. A high level of hygiene
must be guaranteed by all components of the air conditioning system, including the
air distribution channels.
[0003] Micro-perforated channels for the distribution of an air flow, e.g. treated air to
condition a room: cooled air, heated air and the like, are known in the state of the
art. Normally, air distribution systems comprise a suitable canalization by means
of which an air flow is transferred from a device designed to supply energy to the
air flow in the form of a pressure increase (e.g. a fan) to an area of use of the
air flow, such as a particular room, an office, a laboratory, a workshop or the like.
[0004] Furthermore, such canalization generally comprises one or more sheet metal transport
channels and one or more terminal venting elements, such as perforated diffuser channels
made of sheet metal or flexible materials, for example fabrics. In particular, the
diffuser channels, whether made of metal or flexible materials, have the task of homogeneously
distributing the air in the area of use and, for this purpose, are provided by a plurality
of holes arranged along one or more walls of the channel.
[0005] Channels of the known type, along with large flows of air also distribute large flows
of dust particles and along with them also mites, bacterial and viral particles. Internal
coatings of such channels with antibacterial materials are also known, e.g. paint
applied to the inside of the channel. The components of the paint inhibit the proliferation
of colonies of the most common types of bacteria and contribute to their destruction.
Tests in accordance with ISO 22196:2007 carried out in specialized laboratories have
shown effective action in reducing colonies of the following bacteria by more than
99.99% within 24 hours: Staphiloccous Aureus, Escherichia Coli O1257, Legionella Pneumophila,
Salmonella Enteritidia, Pseudominas aeruginosa, Enterobacter Aerogenes, Enterococcus
Faecalis.
[0006] Antimicrobial coated channels are therefore suitable for use in public places such
as schools, hotels, cinemas, theatres and offices, but especially in places where
hygiene is essential: hospitals, operating theatres, food industries and pharmaceutical
industries. Antimicrobial canalization can also be a great help to all those who suffer
from allergies, asthma and chronic respiratory problems, allowing them to have a healthier
and quieter life at home. However, channels with a known antibacterial or antimicrobial
coating cannot completely prevent the formation of colonies and clusters of bacteria
and mites within them.
This is due to the fact that the methods commonly used for creating the perforation
in channels with an antibacterial or antimicrobial coating fail to keep the edges
of the hole intact, inevitably also removing part of the antibacterial treatment from
these edges, thus making them areas in which bacteria and microbes easily nest.
There is, therefore, a need to realize an innovative air distribution channel which
is extremely efficient and able to reduce as much as possible the formation and diffusion
of bacterial and microbial particles.
Summary of the invention
[0007] The aim of the present invention is to optimize micro-perforated air distribution
channels with an antibacterial coating in order to minimize the formation of colonies
and clusters of bacteria and mites inside them.
[0008] This aim, which is the main purpose of the present invention, is achieved by optimizing
the number, i.e., the density, and the shape characteristics of the air outlet holes
in the channels themselves.
[0009] A specific calculation algorithm makes it possible to calculate an optimal perforation
density with respect to the surface of the channel, so that the necessary amount of
antibacterial coating is preserved inside the tube.
[0010] In addition, the calculation algorithm makes it possible to calculate and establish
the optimal distribution of the air and therefore of the summer/winter comfort in
the treated environments, limiting the phenomena of stratification and excessive residual
velocities at human height. In particular, the specific perforation made will avoid
the formation of condensation both inside and outside the channel itself.
[0011] The micro-perforated channels, which are the subject of the present invention, are
therefore designed to maximize the principle of induction of the conditioned air,
which depends on the speed of the air flow and serves to reduce the mixing time between
the outgoing air and the surrounding air, thus limiting the effect of air stratification
present in conventional systems. The application of this feature to the channels makes
it possible to move many more volumes of air than those introduced (from 5 to 20 times
depending on the type of system) and consequently the diffusion in the environment
is more homogeneous compared to traditional systems with diffusers or vents. Furthermore,
by drastically reducing stratification, the time required to set up and maintain the
system is reduced.
[0012] Advantageously, the micro-perforation carried out on the channels allows the air
to flow inside the channel, creating special swirling motions, and then escape from
the channel and diffuse into the area of use.
[0013] Therefore, the micro-perforated channel object of the present invention, is configured
to extremely efficiently prevent the proliferation of bacteria, as specified in the
attached independent product claim.
[0014] According to another purpose, the making of the channels is carried out by means
of a specific method according to the attached independent method claim.
[0015] According to a further purpose, an aeration system comprising a plurality of micro-perforated
channels is defined according to the attached independent system claim.
[0016] Further preferred and/or particularly advantageous ways of implementing the invention
are described according to the features set out in the attached dependent claims.
Brief description of the drawings
[0017] The invention will now be described with reference to the appended drawings, which
illustrate some non-limiting implementation examples, wherein:
- figure 1 shows a micro-perforated channel in a first embodiment according to the present
invention;
- figure 2 shows a micro-perforated channel in a further embodiment, according to the
present invention;
- figure 3 is an overall view of the micro-perforated channel system in an aeration
system, according to the present invention,
- figure 4 is a table relating the dimensioning of the diameter of the micro-perforated
channel in relation to the required flow rate,
- figure 5 shows the fixing system of a micro-perforated channel, according to the present
invention,
- figure 6 shows the punch and the special die used for perforating the sheet metal
with antimicrobial treatment.
Detailed description
[0018] With reference to the above figures, Figures 1 and 2 show a micro-perforated channel
100, 101 for distributing air, according to two embodiments of the present invention.
The channel 100 is a channel with a constant diameter, while the channel 101 is a
channel with a variable diameter.
[0019] The channel 100 comprises: a plurality of pipe sections 10 stably connected to each
other, a plurality of openings or holes 11 and an antibacterial inner lining (of known
type and therefore not shown in the appended figures).
[0020] The channel 101 also comprises a plurality of metallic pipe sections 10, but having
variable diameters and joined together by means of truncated cone fittings 12. It
also comprises the plurality of openings or holes 11 and the antibacterial inner coating.
The anti-bacterial coating is achieved by applying a paint with anti-bacterial properties
to one side of the metal surface, which once folded will form the plurality of pipe
sections 10, i.e. the portion that will form the inner surface of the channel 100,
101. The painting treatment of the metal sheet (inner part of the channel) is carried
out with a special material with antimicrobial properties. The treatment is carried
out in the following stages
- carry out two degreases and a chrome-free passivation;
- apply a 5-7 micron thick "primer" to the upper face and then apply a 15-20 micron
thick white top coat.
or, alternatively
- apply a 5-7 micron thick "primer" to the upper face (steel only), then apply a 10-15
micron thick PE base coat and finally apply a 12 micron thick clear topcoat.
- on the lower face apply a "back coat" with a thickness of 4-6 microns.
[0021] This treatment gives a UV resistance category: RUV2, a corrosion resistance category:
RC2 and a fire category: A1, according to EN 13501-1. The paint used complies with
the ROHS directive.
[0022] The channel 100, 101, subject of the present invention, has along the entire length
of the pipe sections 10 a plurality of holes 11 obtained through the use of a specific
punch. In other words, the punch used is able to make a suitable perforation, in order
to obtain the specific air induction characteristics, without affecting and excessively
reducing the removed surface of the channel. In particular, its punching action makes
it possible to obtain a precise hole that creates less waste, thus minimizing the
breakage of the antibacterial coating.
[0023] The use of a specific punch in the presence of the plurality of holes lion the channel
100, 101 is therefore indispensable for all sections of the channel, so as to prevent
the rooting of impurities and bacteria even in the areas of the holes 11.
[0024] The punch 50 and its die 60 as shown in Figure 6 are characterised by a reduced clearance
of between 15% and 20% compared to standard tools. According to a non-limiting example,
the backlash of the standard die 60 is 0.18 mm, whereas the backlash of the die 60
of the punch 50 used in the present invention is 0.15 mm.
[0025] Such holes 11, should be made with a drilling density of between 5% and 10% of the
entire surface of the channel 100, 101. Advantageously, as shown by statistical and
experimental data, this drilling density is 7% of the entire surface of the channel
100, 101.
[0026] This optimization of the perforation density is fundamental in order to balance two
characteristics which are in trade-off: on the one hand the air circulation and on
the other hand the quantity of antibacterial coating inside the tube. Obviously, as
the perforation density increases, air circulation increases and the effectiveness
of the antibacterial coating decreases. The optimum perforation density value can
be obtained by means of a calculation algorithm implemented on a special software
application.
[0027] Advantageously, the presence of a plurality of efficiently distributed holes 11 allows
for turbulent motions within the channel 100, 101 so as to prevent the formation of
moisture and optimal circulation of the outgoing air both inside and outside the channel
itself.
[0028] Advantageously, the channel 100 are made, for example, of galvanized sheet metal,
or galvanized sheet metal painted in colors according to RAL color scale coding.
[0029] Advantageously, the presence of the holes 11 generates a more homogeneous diffusion
of air to the outside environment, compared to conventional diffusers.
[0030] By means of the aforementioned calculation algorithm it is also possible to carry
out the complete dimensioning of the channel 100, 101 and in particular the choice
of the diameter of the piece of pipe 10, in the case of a constant diameter channel,
or of the diameters of the single pieces of pipe 10 in the case of variable diameters.
Furthermore, the software application is able to graphically show the air diffusion
inside the treated room. Such calculations and visualizations make it possible to
analyze in a punctual manner both the penetration of the treated air with respect
to the volume of the room, and the isometric lines of speed. According to the present
invention, the air outlet points or distribution holes are dimensioned taking into
account the following parameters:
- air flow rate (summer/winter);
- useful head available to the system;
- length of the channel;
- height of the channel axis from the floor;
- distance from the ceiling;
- width of the area treated by the channel.
[0031] Thus proceeding, the software application can dimension an entire system 200 for
air distribution, as shown in Figure 3. The system 200, comprises an air treatment
unit 30 connected to a supply channel 20 also provided with antimicrobial treatment
and a plurality of micro-perforated and antimicrobial channel 100, 101. The air handling
unit is provided with a plurality of panels 35.
[0032] The panels 35 may be made of sheet metal having an antibacterial inner coating. The
sheet metal having an antibacterial inner coating provides effective protection (e.g.,
certified according to JIS Z 2801:2000A and ISO 22196:2011-08) against a wide range
of microorganisms, including:
- Escherichia Coli;
- Staphylococcus Aureus;
- Methicillin Resistant Staphylococcus Aureus (MRSA);
- Klebsiella Pneaumoniae;
- Salmonella Typhi;
- Enterococcus Faecalis;
- Pseudomonas Aeruginosa;
- Legionella Pneumophila.
[0033] The antibacterial coating is white with a smooth finish for ease of cleaning and
washability.
[0034] Therefore, the air distribution system 200, equipped with both panels and channels
with antibacterial internal treatment, ensures uniformity of antimicrobial treatment
throughout the plant.
[0035] In addition, the table in Figure 4 shows an example of the sizing of channel 100,
101. The table shows the value of the channel diameter in the left column and the
value of the air flow rate in the right column. For each diameter value the correct
flow rate is indicated. In the design phase, the correct diameter is chosen as a function
of the flow rate, while in the verification phase the flow rate corresponding to the
chosen diameter can be found. This two-way correspondence of diameter <=> flow rate
ensures that the channel is suitable for installation. For example, for a diameter
of 200 mm the flow rate will be 790 Mc/h.
[0036] According to the present invention, a method for making a micro-perforated channel
100, 101 for air distribution is also described, comprising the following main steps:
- painting the sheet metal (inner part of the channel) with a paint having antimicrobial
properties;
- punching the sheet metal to form the holes using a special punch;
- making interlocking profiles on the edges of the sheet;
- calendering the sheet metal to form the channel;
- close the interlocking profiles.
[0037] Furthermore, as shown in Figure 5, in order to obviate further perforations on the
channel 100,101 required during installation of the channels on the ceiling, the channels
100, 101 may be provided with suitable anchorages 40. In particular, the anchorage
40 comprises a suspension means 41 surrounding the channel 100, 101 in turn closed
by a locking means 42 and fixed by an anchoring means 43 to the ceiling.
[0038] In addition to the methods of implementing the invention, as described above, it
is to be understood that there are numerous further variants. It should also be understood
that the above-described embodiments are merely illustrative and do not limit the
subject matter of the invention, nor its possible applications or configurations.
On the contrary, although the above description makes it possible for a person skilled
in the art to implement the present invention at least according to an exemplary configuration
thereof, it should be understood that numerous variations of the described components
are conceivable, without thereby departing from the subject of the invention as defined
in the appended claims.
1. Micro-perforated channel (100, 101) for air distribution comprising a plurality of
pipe sections (10) steadily connected to each other, a plurality of holes (11) and
an antibacterial internal coating, said micro-perforated channel (100, 101) being
characterized by the fact that the density of the plurality of holes (11) is between 5% and 10% of
the entire surface of the micro-perforated channel (100, 101) so as to guarantee the
generation of turbulent motions inside the micro-perforated channel (100, 101) and
at the same time keep the characteristics of the antibacterial coating intact to prevent
the rooting of impurities and bacteria.
2. Micro-perforated channel (100, 101) according to claim 1, characterized by the fact that the density of the plurality of holes (11) is exactly equal to 7% of
the entire surface of the micro-perforated channel (100, 101).
3. Micro-perforated channel (100, 101) according to claim 1 or 2, further provided with
an anchorage (40) comprising a suspension means (41) surrounding the micro-perforated
channel (100, 101) which is in turn closed by a locking means (42) and secured by
an anchoring means (43) to the ceiling.
4. Micro-perforated channel (100) according to any of the preceding claims, wherein the
plurality of pipe sections (10) has a constant diameter.
5. Micro-perforated channel (101) according to any one of claims 1 to 3, wherein the
plurality of pipe sections (10) has a variable diameter and the individual pipe sections
(10) are joined together by means of truncated cone fittings (12).
6. Air distribution system (200) comprising an air treatment unit (30), provided with
a plurality of panels (35), connected to a supply channel (20) also provided with
antimicrobial treatment and characterized by antimicrobial treatment and characterized by a plurality of micro-perforated channels (100, 101) micro-perforated as defined according
to any of the preceding claims.
7. Air distribution system (200) according to claim 6, wherein the plurality of panels
(35) is made of sheet metal provided with an inner antibacterial coating.
8. Method for realizing a micro-perforated channel (100, 101) as defined according to
any of claims from 1 to 5, said method being
characterized by the following steps:
- painting the metal sheet (inner part of the channel) with a paint having antimicrobial
properties;
- punching the metal sheet to form the holes by means of a specific punch characterized by a clearance of the die equal to 0.15 mm;
- making interlocking profiles on the edges of the sheet;
- calendering the sheet to form the channel;
- closing the interlocking profiles.