Supply air terminal unit

A supply air terminal unit (10) has a body (11) with side walls, top and bottom walls and an opening cover, which is opened to allow access for service work inside the structure. A wall structure (12) formed by needle-fin tubes (100) is fitted around a central fine filter (13), whereby the needle-fin tubes (100) are placed on top of each other in order to form a filter wall (12). A needle-fin tube (120) has needle-like fins whereby in its tube a heat carrier is made to flow in order to transfer heat into the air made to flow through the structure or in the opposite direction. The fine filter (13) covers an air outlet port (A2) located in the bottom (11a5) of the supply air terminal unit.

CROSS REFERENCES TO RELATED APPLICATIONS

This application claims priority on Finnish App. No. 20075115, filed Feb. 16, 2007, the disclosure of which is incorporated by reference herein.

Not applicable.

BACKGROUND OF THE INVENTION

The invention concerns a supply air terminal unit.

Separate machine rooms in connection with supply air arrangements are known in the state of the art.

SUMMARY OF THE INVENTION

This application presents a supply air terminal unit solution of quite a new type, which is especially suitable for use as a supply air terminal unit for mounting on the roofs of buildings and which looking from the direction of airflow comprises a heat-transferring pre-filter wall, an air fine filter and possibly also a second heating step. According to the invention, the filter wall of the pre-filter is made of needle-fin tubes in the unit. The pre-filter is placed in the unit's interior space E as a peripheral structure, whereby air will arrive in space E from the sides.

As presented in this application, the needle-fin tube comprises a band wound around the tube proper and comprising in two rows needle-like fins, which are positioned at an angle in relation to one another. Said adjacent needle fins thus form an acute angle in relation to each other, in which angle impurity particles will depending on their size be caught in the filtration event. In the needle-fin tube proper, heat can be transferred through the fins from the air or the air can be heated in the opposite direction through the needle-fin tube.

According to the invention, the unit is formed by a box-like and preferably rectangular cross section or also in one embodiment of a circular cross section. As described above, as seen in the supply air flow L1, the first component is at least one filtering wall12formed of needle-fin tubes. The wall in question is a peripheral structure positioned around a second filter13. Inside the wall12formed by a needle-fin tube there is thus a fine filter13, which is formed as a cassette-like modular unit, which when contaminated can be easily exchanged and/or cleaned. The air supplied through the supply air terminal unit10can be either cooled or heated and filtered with the aid of the needle-fin tube wall12. In the direction of the airflow L1, the equipment may after the pre-filter12also comprise a separate heating coil (not shown) in order to produce a final temperature for the airflow L1.

The filters, pre-filter and fine filter or after-filter as well as a possible after-heater are fitted into the unit in this manner. Above the concerned structures there is an opening top cover, whereby the structures are easily accessible for service in order to clean/exchange/inspect them, whereby the serviceability of the unit is good.

It was realized in accordance with the invention to fit the after-filter or fine filter13to cover an outlet port A2located in the bottom of the supply air terminal unit. In accordance with the invention, in connection with the outlet port A2there is a latticework, on top of which the filter modules are piled to form a uniform fine filter. In connection with service work it is easy to exchange each module by opening the top cover of the supply air terminal unit. Service work according to the invention is easily done, because there is easy access to the filter modules from above. According to the invention, the filter modules are thus resting on the latticework, and each one of them is fastened by screws or other such clamps to lattice beams or other such. When the airflow is leaving the after-filter or fine filter modules13a1,13a2, the airflow has a direction L1′, which is essentially perpendicular in relation to the direction of arrival of the air in the chamber E inside the unit.

The supply air terminal unit in question can be mounted either on a roof or also inside the building. For the supply air flow, the unit comprises an opening above and below and possibly a lattice therein. The opening is also formed as a circular flow gap.

The invention will be described in the following by referring to some advantageous embodiments of the invention, which are shown in the figures of the appended drawings, but there is no intention to restrict the invention to these embodiments alone.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1A,1B and1C show the supply air terminal unit10according to the invention. The supply air terminal unit10comprises a box structure11, which comprises side walls11a1,11a2,11a3and11a4and a bottom wall11a5as well as an opening top cover11a6. An airflow gap D1and D2is left on each side of the square structure in its upper and lower parts, whereby air can be made to flow as shown inFIG. 1Bby arrows L1from outside into the space E inside the structure and from space E in the direction of arrow L1′ and out through an outlet port A2.

As shown in theFIGS. 1A,1B and1C, and seen in the direction of the supply airflow L1, the supply air terminal unit10comprises a first filter12, which is a so-called pre-filter, which preferably is a coarse-mesh filter and formed by needle-fin tubes in accordance with the invention. The needle-fin tubes are placed on top of one another and they form a wall structure functioning as a filter and as a heat exchanger. (FIGS. 3A,3B and3C show the structure of a needle-fin tube). After the pre-filter12in the flowing direction of airflow L1a fine filter or after-filter13is located.

As shown in the figures, the pre-filter12is fitted around the after-filter13as a peripheral structure to surround it. By the above-mentioned location of the filters around duct300a large filtering cross-section is achieved and correspondingly a small pressure loss over the filters. The device10preferably comprises a pressure sensor17a1in front of the filters12,13and a pressure sensor17a2after the filters12,13in relation to the direction of flow L1, whereby in the device solution any pressure difference will be detected between the sensors17a1,17a2and thus the purity of the filters12,13is indicated as well as their possible degree of clogging and need for exchange.

If the filters12,13are clogged and they must be washed/exchanged, this is easily done in the structure according to the invention by opening the supply air terminal unit's top cover11a6, whereby there will be access to the filters12,13in space E. Space E can be a service space. The pre-filter12can be washed by a jet of water under pressure, and the fine filter13can be exchanged or taken away for cleaning. The pre-filter's12filtration class is EU3 and the after-filter's or fine filter's12filtration class is EU7, EU8 or EU9 or even more efficient.

shown inFIGS. 1A,1B and1C, after the pre-filter12formed by needle-fin tubes100there is a fine filter or after-filter13. The fine filter or after-filter13is located in connection with the outlet port in chamber E of the supply air terminal unit10, that is, in connection with outlet port A2from space E in the bottom of chamber E. The fine filter13is arranged to cover the outlet port A2tightly. The fine filter13is advantageously formed modularly of filter units13a1,13a2,13a3. . . , which may be, for example, filter items of a size of 60×60 cm, which are piled to cover the air outlet port A2on top of the latticework200. A compact filter13is also possible. The latticework200may comprise elongated metal fins f1, f2. . . , which extend through port A2and on top of which the filter modules13a1,13a2,13a3. . . are piled to rest by gravity (the direction of the earth gravity field is indicated by an arrow g1), as shown inFIG. 1B. The flow away from filter13along duct300is in the direction of arrow L1′, that is, in the direction of the earth's gravity field g1and essentially at right angles in relation to the flow L1taking place from pre-filter12into space E. To port A2a barrel or outlet duct300is connected, which branches off into a plurality of branch ducts301,302,303, each one of which may comprise an air conditioner O1, O2, O3. . . comprising a damper S1, S2, S3after this a fan P1and a noise trap V1. The outlet duct300is also a supply air duct into the building. However, no separate filter is needed in the concerned air conditioner, because the filter for the entire structure is formed by the supply air terminal unit10according to the invention with its pre-filter12and fine filter13. Each air conditioner O1, O2, O3. . . located in one of the plurality of branch ducts301,302,303of the barrel or outlet duct300having a corresponding fan P1, P2, P3. . . and these fans can be operated independently of each other. The functioning ability of the system is guaranteed by the linear conductance of the pre-filter12used, which is formed by needle-fin tubes100, as shown inFIG. 3E, which makes it possible for the heat exchange in regard to the pre-filter12to work both at low fan speeds and airflow rates and also at high fan speeds and airflow rates. The after-filter or fine filter13works perfectly at all times, because after the pre-filtration the air is clean and dry. This is guaranteed by the needle-fin tube structure used as the pre-filter structure.

The pre-filter12is formed by filter modules13a1,13a2,13a3. . . , which are piled to cover the outlet port A2. This makes easy serviceability of the structure possible, because the supply air terminal unit10comprises an opening cover11a6, which when opened allows easy access into the service space D and to the filter13and its modules13a1,13a2,13a3. . .FIG. 1Dillustrates the modular filter structure in connection with the outlet port A2. The filter modules13are assembled on top of a lattice network f1, f2. . . covering the outlet port A2and attached tightly to the lattices, for example, by screws. No bypassing leakage can occur. When the filter13is exchanged, the attachment is opened and the filter modules13a1,13a2,13a3are removed from the structure by opening the top cover11a6in the manner shown by arrow M1inFIG. 1B. Top cover11a6can be turned carried by hinges to an opened and closed position or it can be put aside when opening it. The modules13a1,13a2. . . rest under their own weight (the direction of the gravity field is indicated by g1) on top of lattices f1, f2. . . and they are attached to the lattices f1, f2. . . in a removable manner.

FIG. 1Dillustrates a module, the size of which can be 60×60 cm. Always depending on the air volume of the supply air terminal unit, it is possible to choose the size of the supply air terminal unit's10opening A2and thus the size of the lattice network f1, f2. . . and the modular after-filter13covering the same.

In the supply air terminal unit10according to the invention, the direction of flow L1of the airflow from pre-filter12into chamber D is essentially at right angles in relation to the direction of discharge L1′ of the airflow from port A2into the exit duct and into the supply air duct300of the building. Under these circumstances, airflow L1changes its travelling direction by about 90° when leaving chamber D for the exit duct300. Filter modules13a1,13a2. . . may be such structures, that they have several filter layers. The filter may be, for example, a conical structure, thus comprising an air space inside the cone. A supply air terminal unit10which is to be placed on a roof15may thus serve several supply air terminal devices O1, O2, O3. . .

The supply air terminal unit10may be provided with pre-heating (heat recovery), cooling, pre-filtering (needle-fin battery)12and main filtration of the supply air and possibly also with an after-heating function (by needle battery14) of the supply air. The plane of port A2is indicated by T1inFIG. 1D. The filter13forms a plate-like structure located in a horizontal direction. The filter structure may be formed by a serrated profile in cross-section. The after-heating unit may be located in space E after the pre-filter12and it too may be formed by a wall formed by needle-fin tubes100. It may also be located peripherally around the fine-filtration unit13.

The supply air terminal unit10can be dimensioned for a smaller airflow than the totalled design airflow of the fans P1, P2, P3, . . . of each of the plurality of exit ducts301,302,303of the supply air terminal devices serving the supply air terminal unit. This is due to the fact that the serving supply air fans P1, P2, P3, . . . of the plurality of exit ducts301,302,303of the supply air terminal unit10will not probably ever be working all at the same time at full airflow. Calculated by a simultaneity coefficient of 0.7, the supply air terminal unit10can be dimensioned for an airflow which is smaller by 30% in comparison with state-of-the-art heat recovery, cooling and filtration solutions for specific devices.

FIG. 2shows how the supply air terminal unit10is located in position A1, that is, on the roof15of a building H, and the figure also shows another position A2, in which the supply air terminal unit is fitted on a wall16of the building H.

FIG. 3Ashows a needle-fin tube100according to the invention.FIG. 3Bis a cross-sectional view along line III-III ofFIG. 3A, andFIG. 3Cis a cross-sectional view of a fin band along line IV-IV ofFIG. 3B.FIG. 3Dshows the structure in the direction of arrow K1ofFIG. 3B. As shown inFIGS. 3A,3B,3C and3D, the needle-fin tube solution100comprises a central tube120, to which the fin band121is joined by winding it and attaching it around the tube120.

As shown inFIG. 3C, the needle-fin band121has two adjacent needle rows n1and n2, whose opposite needle fins111a1,111a2are at an acute angle α1in relation to each other. Said angle α1is an acute angle, whereby impurity particles will be caught at various height positions in between adjacent fins111a1,111a2. The needle-fin tube100functions both as a filter and as a heat exchanger. Heat can be transferred through it from a heat carrier made to flow inside tube120through the needle fins111a1,111a2. . . into the air or heat can be transferred in the opposite direction from the air from the flow L1through the needle fins111a1,111a2. . . into the heat carrier made to flow centrally in tube120, whereby the airflow L1will be cooled. Both purposes of use are possible. The fin band121comprises a base part a and folded covering parts b1and b2, to which the needle fins111a1,111a2. . . are joined. Thus, the needle-fin tube100can be used in the manner shown inFIG. 3E. The needle-fin tubes100are formed as a filter wall12, whereby a heat carrier is conducted from the distributing manifold J1into each needle-fin tube120on the wall12, and the heat carrier is removed from distributing manifold J2. Wall12forms the pre-filter's so-called coarse-mesh filter and a heat exchanger, after which the equipment comprises a fine filter13, with which impurity particles of a smaller particle size can be removed from the air after the pre-filtration.