WO1994011679A1

WO1994011679A1 - Modular ventilating unit with integrated fan and connected filter casing, especially for clean rooms

Info

Publication number: WO1994011679A1
Application number: PCT/EP1993/000608
Authority: WO
Inventors: Rüdiger DETZER; Andreas Balzer; Walter Scholz
Original assignee: Kessler + Luch Gmbh
Priority date: 1992-11-16
Filing date: 1993-03-16
Publication date: 1994-05-26
Also published as: DE4238595A1; DE4238595C2

Abstract

In order to extend a modular ventilating unit (1) with a rectangular housing (2) with a cover plate (3) with an intake aperture (3.3) to the plenum and a base plate (5) and an overflow aperture (15) to the pressure chamber (6) of the filter (7.1), with an integrated fan and a connected filter casing (7) with filter (7.1) in such a way that it can be simply and economically produced and by means of which air can be fed from a plenum into a space at a reduced noise level, it is proposed that an insert (10) of sound-damping material be inserted between the cover and base plates (3, 5) to form a kind of sandwich in which, corresponding to the intake aperture (3.3), is formed a spiral chamber (11) with a discharge aperture (13) and a discharge channel (14) connected thereto with mutually angled oblique surfaces (14.1, 14.2) at the two lateral borders of the overflow aperture taking the form of an overflow slit extending over the internal width of the housing (2). The spiral chamber (11) is fitted with the impeller (12) with drive (12.1) of the fan, arranged coaxially to the inlet pipe (11.1) inserted in the intake aperture (3.3), and the discharge channel (14) with the cover and base plates (3, 5) form a rectangular diffuser.

Description

Modular ventilation unit with integrated fan and connected filter frame, especially for clean room technology purposes

The invention relates to a modular ventilation unit, in particular for ventilation ceilings or walls in clean rooms, with a rectangular housing, integrated fan and connected filter frame, into which a filter can be inserted, the housing having at least one cover plate offset to one end of the housing Has suction opening to the plenum and a base plate with an overflow opening to a pressure chamber above the filter, which are formed from sound-absorbing material.

In clean room technology, a large-scale flooding of a Clean room with filtered air used in order to be able to carry out the productions or activities to be carried out under clean room conditions. For this purpose, filter ceilings or filter walls are installed under the solid ceiling of the building or next to the solid walls of the building, the space between the solid ceiling and filter ceiling or between the solid wall and filter wall - the plenum - is supplied with conditioned air by a ventilation center. In many areas it is expedient if the manufacturing conditions can be divided into areas or zones in which different conditions prevail; as a result, the possibility of using a clean room system is made more flexible, the corresponding cleanliness conditions only having to be observed in the critical zones. This flexibility can be achieved with a modular system. A modular filter unit suitable for clean room technology purposes is known from DE-OS 3422 900, in which the individual filter modules, provided they are not supplied with air pressed into the ceiling space by a ventilation center, are provided with air supply hoods which are connected to a ventilation center via ^' n branched piping system according to the arrangement. This modular system requires a considerable amount of assembly work, since these pipelines with their branches have to be installed in the space between the solid ceiling of the building and the filter ceiling of the clean room.

In order to overcome this disadvantage, a filter / fan combination is used according to DE-OS 3513 902, in which each of the filter modules is provided with a centrifugal fan which, from above, is placed on a filter frame with a filter (high performance suitable for clean room technology -Sulfide filter) is set, this ventilator sucks the air from the ceiling space, the plenum, and pushes it through the filter into the clean room. In all these cases, the backflow generally takes place directly, on the one hand, and, on the other hand, via a ventilation center. In the device according to this There are problems with maintenance and repair, especially when the parts of the fan which are susceptible to wear are affected, since there is generally only very limited movement for a maintenance man in the plenum.

DE-OS 3836 147 attempts to further develop this state of the art so that the modularly designed clean room ceiling can be maintained and repaired in a particularly simple and cost-saving manner and that it is also easy to assemble, in particular because the large number of Pipe connections from the individual filter modules to the ventilation center. For this purpose, she proposes a housing with an inflow and an outflow side, the inflow side having an air inlet opening and the outflow side having a circumferential filter frame, in which a high-performance particulate filter which is customary in clean room technology is inserted as a filter an integrated fan is also provided, the air inlet opening being arranged offset with respect to the inflow nozzle of the fan in such a way that the sucked-in air is guided through a first channel-like slot, reaches the fan and from there runs into a second slot parallel to the first slot, channel-like slot is pressed until an overflow opening located approximately below the inflow opening permits this conveyed air to pass into the pressure space assigned to the raw air side of the filter, these slots being formed by sound-absorbing guide walls. A chamber, in particular a spiral chamber, is provided for the impeller of the fan. The disadvantage here is the air pressure-related pressure loss, which leads to increased power consumption of the fan - power consumption of more than 300 w / πr is definitely achieved. These pressure losses have the consequence that the fan of such ventilation units must be operated at an increased speed, which leads to an increased sound power output, so that the sound level cannot fall below about 55 dB (A). In addition, the Fan supported on one side against one of the guide surfaces made of sound-absorbing material, this guide surface must be reinforced statically, and a particle detachment from the sound-absorbing material, which is a burden on the downstream filter, cannot be ruled out as a result of the vibrations caused by the fan never running quite smoothly.

To remedy this disadvantage is the object on which the invention is based, and according to which a ventilation unit is to be further developed such that its supply air can be taken from a room (plenum) located above the ventilation ceiling or next to the ventilation wall, as a result of which (Almost) any room size can be supplied with a vertical or with a horizontal air flow with low-turbulence displacement flow in the downflow or in the crossflow, whereby the sound level of the ventilation unit should be reduced, it should be simple and economical to manufacture, while continuing the task the particle detachment from the sound-absorbing material is to be suppressed, and finally the possibility is to be created in a simple manner to change the air temperature.

This object is achieved according to the invention by the features of the main claim; Advantageous further developments and preferred embodiments describe the subclaims.

According to the invention, an insert of sound-absorbing material, covered on both sides in the manner of a sandwich construction, is provided between the top and bottom plates, in which, corresponding to the suction opening, there is a spiral chamber with a blow-out opening and a blow-off duct connected to it with an angle to one another and to the two lateral boundaries the overflow opening, which is designed as an overflow opening and extends over the inner width of the housing, is formed, the spiral _β _

Chamber is provided with the impeller arranged coaxially to the inlet nozzle inserted into the suction opening and the fan drive, and wherein the blow-out channel forms a rectangular diffuser together with the top and bottom plates. With this design, a flow-appropriate design of the air delivery device is achieved, which keeps the pressure increase to be applied by the fan low and increases the efficiency of the fan and thus reduces its power consumption. Deflections that consume a significant part of the flow energy are largely avoided so that the necessary pressure increase in the fan can be reduced. In addition to the associated reduction in the power consumption of the fan, the sound power output by the fan is also reduced, so that excessive noise reduction can be dispensed with.

One of the inclined surfaces is advantageously oriented approximately tangentially to the spiral and the other approximately tangentially to the rotating circle of the impeller, the inclined surface extending tangentially to the spiral preferably running parallel to one of the side walls of the housing. The rectangular diffuser thus formed between the top and bottom plates thus opens towards the overflow slot, in which the outflow speed from the volute casing under pressure recovery to the overflow slot is reduced to such an extent that the overflow takes place with (relatively) little pressure loss. A flow-appropriate adaptation is thus achieved, which further reduces the pressure increase required in the fan and also limits the sound power generated by the fan, with the result of a further reduction in both the power consumption of the fan and the sound level of the ventilation unit. It has been shown empirically that a flow-appropriate adaptation is achieved when one of the inclined surfaces is oriented approximately tangentially to the spiral and the other approximately tangentially to the rotating circle of the impeller. In this case, one of the inclined surfaces is preferably aligned parallel to a side wall of the housing, as a result of which an advantageous opening of the blow-out duct is achieved. The rectangular diffuser thus formed with the top and bottom plates and opened towards the overflow slot effects a flow-appropriate adaptation of the blow-out speed of the fan to the air speed in the overflow slot. For this purpose, the blow-out jet guided over the rectangular diffuser is expanded to the width of the Housing expanded, the height of the beam is kept constant at least in the region of the diffuser and the diffuser also has a sound-absorbing effect. This also reduces flow losses, which in turn leads to a reduction in the pressure increase required in the fan, with the effect on power consumption and noise level, the latter being able to be reduced by more than 10 dB (A).

The overflow slot is advantageously made over the entire width of the interior of the housing, and its length is 1/6 to 1/4 of the length of the housing. This configuration of the overflow slot ensures that the conveyed air flow overflows to the filter over the entire width of the interior of the housing, with the deflection speed of the air contributing to the usual filter outlet speeds of around 0.4 to 0.5 m / s 1.6 to 3 m / s, a speed which does not lead to any special problems with deflection losses and the resulting flow noise. In an advantageous embodiment, a foamed plastic is used as the sound-absorbing material of at least the spiral chamber with insert containing a blow-out channel, into which the spiral chamber and blow-out channel are molded. On the one hand, this design makes use of the favorable properties of a radial fan with a spiral housing, with its overall good efficiency; on the other hand, the blow-out diffuser, which is formed in a surprisingly simple manner, allows pressure to be recovered, which generates the pressure difference required to generate the clean room operation in order to overcome the _ *

the level of the filter is reduced and so is the power consumed by the fan. In particular, the use of foam material has proven to be an effective measure for sound absorption, the spiral of the blower and also the inclined surfaces of the rectangular diffuser being able to be molded in a simple manner, for example by cutting, since their boundaries are cylindrical or are even. In this way, an inexpensive manufacturing possibility is achieved, which allows economical manufacturing. It goes without saying that both the top and bottom plates can also be formed from foam, but other materials known from the art of soundproofing can also be used, such as mineral wool or the like. insert perforated sheets. With this embodiment it is achieved that on the one hand the fan is completely encapsulated. The use of molded foam is advantageous, which allows simple and efficient production, the foaming preferably being conducted in such a way that the surface is closed-pore. This surface design ensures that a load on the particle discharge which is a burden on the downstream filter is suppressed, which increases the life of the filter.

The cover plate in the region of the overflow slot is advantageously provided with a flow guide deflecting the air flow emerging from the rectangular diffuser, which is preferably designed as an insert formed from sound-absorbing material with a fillet comprising an angle of at least 90 °. This use, which also permits a flow deflection by more than 90 °, reduces the flow losses occurring in the region of the deflection and thus helps to keep the electrical power consumed by the fan for conveying the air flow small.

In a preferred embodiment, the impeller inserted into the spiral chamber is mounted on the base plate with a drive and is detachably attached to it. With this type of fan arrangement voltage is achieved that, if necessary, the fan can be removed and serviced or repaired together with the base plate through the filter holder frame. It is also advantageous if the impeller arranged in the spiral housing is provided with backward curved blades. As a result, the efficiency of the fan is further increased and its power consumption is further reduced, so that the impeller is operated at a lower speed, which moreover increases due to the dependence of the sound power on the 5th power of the speed leads to a reduction in the sound level.

To improve the flow to the filter, the base plate advantageously has a wedge-shaped bevel on its side facing the filter, which increases from the overflow slot to a maximum of the entire height of the pressure space between the base plate and the upper side of the filter. This wedge-shaped bevel forms a tongue together with the base plate, this base plate being formed in one piece in one embodiment; In another embodiment, the wedge-shaped bevel is designed as a separate molded part and applied to the outside of the base plate. Both embodiments lead to the same result: the cross section of the pressure space above the filter away from the overflow slot is reduced in such a way that there is approximately the same air velocity, thus approximately the same dynamic pressure, in the entire pressure space, which is due to the fact that behind the overflow slot Total pressure prevailing pressure space leads to an even distribution of the static pressure responsible for a uniform filter flow. Differences in the speed of the air with which it passes through the filter can thus be eliminated from the outset.

In this embodiment of the modular ventilation unit, it is possible in a simple manner that a heat exchanger upstream of the intake opening is arranged on the housing; this heat exchanger is connected to a chiller on the primary side. Through this combination of the ventilation unit with a heat exchanger, especially when this is connected to a cooling unit, the temperature of the air blown into the room can be adapted to the requirements, in particular heat loads can be compensated. These warning cutters are connected to one another and to the source with supply and return lines, these connections being tolerable because of their small cross section, in contrast to the air supply lines according to DE-OS 34 33 900.

The ventilation unit formed in this way can be used in conventional grid ceilings; it takes the air to be conveyed from the cavity between the solid ceiling and the suspended filter ceiling, so that further pipeline connections are eliminated. The high sound damping effect thus allows immediate use, the power consumed by the individual fans being tolerable due to the low pressure increase due to the low flow resistance, and requiring no additional measures, for example in the sense of additional cooling. In addition, the ventilation unit according to the invention allows ventilation zones to be formed in a simple manner, for which purpose the drive motors of the blowers can be switched individually or in groups and, if appropriate, the grid boundaries between such ventilation zones are divided by means of suspended separating curtains.

The essence of the invention is described in more detail by way of example with reference to FIGS. 1 and 2; show

Fig. 01: A top view of the ventilation unit with inflow opening; Fig. 02: A longitudinal section through the ventilation unit with a filter underneath.

FIG. 1 shows a top view of the ventilation unit 1 with its surrounding housing 2. The cover plate 3, for reasons of stability Reinforced by means of a reinforcement profile 3.1, this cover plate divides into two parts: while one part contains the inflow opening 3.3 (FIG. 2), the other part covers the outflow channel 14, which is delimited by the two inclined walls 14.1 and 14.2. In the selected illustration, the inclined wall 14.1 continues the spiral of the spiral chamber 11 in such a way that it forms the inside of one of the longitudinal side walls 4. The outflow channel 14 goes on the spiral housing

11 opposite side over into the overflow slot 15, which is formed in that the base plate 5 is not guided up to the overflow side wall 4.1. The side wall 4.2 on the fan side closes the housing. In the half of the housing 2 facing away from the overflow side, the cover plate is provided with the inflow opening 3.3 (FIG. 2), into which the inlet nozzle 11.1 of the fan is inserted. The fan itself is formed by the spiral housing 11 molded into the insert 10 (FIG. 2), into which an impeller

12 (Fig. 2) with drive 12.1 is used, whereby a separate fan housing is unnecessary.

The air conveyed by the impeller 12 of the fan leaves the fan through the blow-out opening 13 and reaches the outflow channel 14, the vc. ..e. The inclined wall is limited to 14.1 and 14.2, here the one inclined wall being formed from the inside of the side wall 4 located in a tangential extension of the spiral of the spiral chamber 11, while the other inclined wall 14.2 is formed in the insert 10 and approximately on a tangent to the impeller circle is guided, the angle to the side wall 4 can also be chosen to be smaller, so that the tangent is related to an inner impeller circle and the blow-out opening becomes wider. By guiding the inclined surface 14.2, the blow-out opening of the fan, which is limited in height by the side walls 4, 4.1 and 4.2, is kept so large that there is no excessive blow-out speed. The inclined surfaces together with the top and bottom plates 3 and 5 form a diffuser in which an expansion of the blow-out jet without jet detachment is possible.

FIG. 2 shows an approximately central longitudinal section through the ventilation unit 1, which is suspended from the hanging iron 1.1 on a solid ceiling of the room to be ventilated. The cover plate 3 is arranged in the housing 2 and is subdivided by the reinforcing profile 3.1. On the overflow side, the cover plate 3 has an inspection opening 3.2, which allows access to the blow-out duct 14; the other side is provided with the inflow opening 3.3. The housing is delimited laterally on the long sides by the side walls 4 and on the narrow sides on the overflow side by the side wall 4.1 and on the fan side by the side wall 4.2. The actual housing 2 is closed off to the filter 7.1 by the base plate 5, this base plate 5 not leading to the overflow-side wall 4.1 to form the overflow slot 15.

The housing 2 of the ventilation unit 1 is carried by the hanging iron 1.1, the filter frame 7 below, which can also be provided with a screen, assumes this carrying function. At the same time, this filter filter 7 below also carries the replaceable filter 7.1, which is sealed all around by means of a liquid seal 7.2. Such a fastening and sealing of the filter is described, for example, in DE-OS 38 17 447. A spiral chamber 11 is assigned to the inflow opening 3.3 in the insert 10 (FIG. 1), which together with the inserted impeller 12 with drive 12.1 is the fan forms, which sucks in the air to be conveyed from the plenum below the (not specified) solid ceiling of the room to be ventilated and presses it through the exhaust opening 13 into the exhaust duct 14. In cooperation with the inclined walls 14.1 and 14.2, the cover plate 3 and the base plate 5, this blow-out duct 14 forms a rectangular diffuser in which the blow-out jet is expanded under pressure recovery. The delayed air flow is directed by means of the quarter-circular flow guide insert 17 through the overflow slot 15 into the pressure chamber 6 in front of the filter 7.1, from which it flows through this filter into the room to be ventilated. The wedge-shaped insert 16 has the effect that the speed of the air in the pressure space upstream of the filter 7.1 is sufficiently evenly distributed despite the outflowing air, so that the speed of the air emerging from the filter into the space to be ventilated is sufficient for the formation of air Clean room technology necessary, low-turbulence displacement flow has sufficient uniform distribution.

Claims

01. Modular ventilation unit, in particular for ventilation ceilings or walls in clean rooms, with a rectangular housing, integrated fan and connected filter frame into which a filter can be inserted, the housing having at least one cover plate with a suction opening offset to one end of the housing and to the plenum has a base plate with an overflow opening to a pressure chamber above the filter, which are formed from sound-absorbing material, characterized in that between the cover and base plates (3, 5) an insert covered on both sides in the manner of a sandwich construction (10) made of sound-absorbing material is provided, in which, corresponding to the suction opening (3.3), there is a spiral chamber (11) with a blow-out opening (13) and a blow-out duct (14) connected to it with an angle to the two lateral boundaries opposite the overflow slot (15) which extends over the inner width of the housing (2) The overflow opening is formed with inclined surfaces (14.1, 14.2), the spiral chamber (11) with the impeller (12) with the drive (12.1) of the fan being arranged coaxially with the inlet nozzle (11.1) inserted in the suction opening (3.3) , is provided, and the blow-out duct (14) together with the top and bottom plates (3, 5) form a rectangular diffuser. 02. ventilation unit according to claim 1, characterized in that one of the inclined surfaces (14.1) approximately tangential to the spiral of the spiral chamber (11) and the other (14th

2) are oriented approximately tangentially to the rotating circle of the impeller (12), the inclined surface (14.1), which runs tangentially to the spiral, preferably running parallel to one of the side walls (4) of the housing (2).

03. ventilation unit according to claim 1 or 2, characterized gekenn¬ characterized in that the overflow slot (15) is guided over the entire width of the interior of the housing (2), and in length at 1/6 to 1/4 of the length of the housing (2) lies.

04. ventilation unit according to one of claims 1 to 3, characterized in that as a sound-absorbing material at least the spiral chamber (11) with blow-out channel (14) containing insert (10) a foamed plastic is inserted in the spiral chamber ( 11) and exhaust duct (14) are formed.

05. ventilation unit according to claim 4, characterized in that the insert (10) is foam-molded, preferably the foaming is conducted such that the surface is closed-pore.

06. Ventilation unit according to one of claims 1 to 5, characterized in that the cover plate (3) in the region of the overflow slot (15) is provided with a flow guide (17) deflecting the air flow emerging from the rectangular diffuser preferably in the form of an insert formed from sound-absorbing material with a fillet comprising an angle of at least 90 ° forms is.

07. ventilation unit according to one of claims 1 to 6, characterized in that the in the spiral chamber (11) ein¬ set impeller (12) with drive (12.1) on the base plate (5) and detachably attached to this.

08. ventilation unit according to claim 7, characterized in that the blades of the impeller (12) are curved backwards.

09. ventilation unit according to one of claims 1 to 8, characterized in that the base plate (5) on its side facing the filter (7.1) has a wedge-shaped slope (16) which rises from the overflow slot (15) and to which Overflow slot (15) on the opposite side fills a maximum of the entire height of the pressure chamber (6) between the base plate (5) and the top of the filter (7.1).

10. Ventilation unit according to one of claims 1 to 9, da¬ characterized in that a suction intake (3.3) upstream of the heat exchanger is arranged on the housing (2).

11. Ventilation unit according to claim 10, characterized in that the heat exchanger is an¬ on the primary side to a refrigeration unit.