GB2065294A

GB2065294A - Heat exchanging ventilators

Info

Publication number: GB2065294A
Application number: GB8038367A
Authority: GB
Original assignee: Wilhelm Gebhardt GmbH
Current assignee: Wilhelm Gebhardt GmbH
Priority date: 1979-11-30
Filing date: 1980-11-28
Publication date: 1981-06-24
Also published as: ATA581380A; GB2065294B; FR2471559A1; CH652480A5; AT387447B; NL8006502A; FR2471559B1

Abstract

A ventilator has an air duct with a fan (4) for the output air current and an air duct (15) for the fresh air input current, and a heat exchanger (1) for heat exchange between the two air currents, one air current moving in a radial direction and the other air current moving in an axial direction through the heat exchanger (1). In another embodiment, Fig. 3 (not shown), two annular heat exchangers of the plate type are arranged in tandem. The heat exchangers may also be of the tubular type. Up to six cross flow type heat exchangers may be arranged round the sides of a polygon, Figs. 4 to 12 (not shown). <IMAGE>

Description

SPECIFICATION A ventilator The present invention is with respect to a roof ventilator and more specially to a ventilator for the input of air and of heat to a room and the output of air from the room. The ventilator of the invention has been more specially designed for hall-like rooms of great floor area and/or of great height.

For ventilating rooms such as assembly shops, rooms used for warehousing, workshops, departmental stores and the like, roof ventilators are used for aspirating the used and stale, but nevertheless still warm, air out of the room to be ventilated and letting it off into the outside atmosphere, this producing the shortcoming, however, of generally high losses of enthalpy, which are undesired because of the waste of power. For this reason, there have, in the past, been suggestions for complex ventilation systems using regenerators or recuperators for causing exchange of enthalpy from the output or stale air to be input or fresh air. However, such ventilation systems as put forward in the past are generally high in price to make and furthermore they take the form of complete systems, designed as a single unit, having the input air and output air fans and heat exchangers.Quite in addition to the high price of producing such plant, there is the further shortcoming that pre-existing systems may not be changed so that they may be put together and used with the new plant. Furthermore, such plant is not flexible and variable with respect to adaptation to different rooms and different designs of building, and the plant is generally only sold as a complete unit. One purpose of the present invention is to take care of these shortcomings in known design art.

For making the nature of the invention clearer, it may be said that one aspect is that of designing an apparatus of the sort in question, which is made up of separate part-units which may be used separately and which may be put together for meeting design needs modularly, such units having for example a heat exchanger, which may be joined up to standardized roof supports (that is to say the supports for the ventilators) and roof fans so that a roof fan system is produced which is responsible for recovery of heat.

In the invention a roof ventilator for ducting an input air current into a room, for input of heat to said room and for ducting an air output current therefrom, having an air duct, together with a fan, for the output air current, and an air duct for the input air current, and with a heat recovery unit for causing heat exchange between the output air current and the input air current, is characterized in that the heat recovery unit is made up of at least one pipe heat exchanger or a ring-like plate heat exchanger designed for motion of one of the two air currents through it radially with respect to the output air fan and for motion therethrough of the other air current in an axial direction, the heat recovery unit being made up, for example, of two such heat exchangers placed in tandem, and into which, for example, the input air current is radially ducted and let out of it, for example axially, while the output air current is ducted axially through the ring-like plate heat exchanger and is axially ducted out of the ventilator, and the heat recovery unit is placed between a roof support, used for fixing the ventilator to the roof of the room, and the inlet or outlet for the axial air current out of or into the atmosphere, for example out of the fan producing the axial air current.

One useful effect of the system of the invention that it may be used for making changes in preexisting ventilation plant without any great change in structure, for the purpose of recovery of heat, the heat exchanger being placed between the roof fan and the roof support or roof foot support. More specially, however, the price of producing a ventilator based on the invention is generally much lower and it may be readily put to use under different conditions and furthermore the separate parts of the ventilator may be sold and used separately, this making for much simpler warehousing on the part of the maker.While the new ventilator of the present invention is simple and low in price, it has a high efficiency and it makes the best use of the space on hand (by making use of a ring-like or annular heat exchanger) while the opening in the roof, for fixing the ventilator in position, is small in size and, furthermore, the input and output air currents may not, generally speaking, be mixed with each other.

The two volumetric currents are completely separate, operation is simple and aerodynamic losses are at a very low level. Furthermore, a simple ventilator is produced, which may be supplied as a complete unit or only in its separate parts, and which, in relation to the cost of producing it, has a very high level of efficiency and may readily be adapted to conditions on hand.

As a further part of the teaching of the invention, the modular make-up of the ventilator may be such that the parts may readily be undone from each other, and put together and furthermore may readily and simply be handled. In fact, it has turned out that the cleaning of heat exchanger element units, frequently necessary with units of the sort in question, is complex and high in price and is, in fact, quite troublesome. The quality of a heat exchanger with respect to heat recovery is in fact dependent generally on the heat exchange face used for heat exchange purposes and the length of time in which the current is present in the heat exchanger so that, looked at from this point of view, a great size of exchange face would seem to be necessary.If, however, the heat exchanger is to be designed not only with a great size of exchange face, while at the same time taking up little space, the spaces between the heat exchange faces have to be very small and attempts have to be made at designing for a relatively great volume weight. Because, however, the input air current through the heat exchanger is frequently unclean and full of dust, the heat exchanger elements and units will become dirty, this process being speeded up if the spaces between the heat exchange faces are small for the reasons noted. Such a dirty condition of the heat exchanger will be responsible for a great decrease in its efficiency, so that it is necessary, from time to time, for the heat exchanger elements and units to be taken to pieces and cleaned.In this connection, however, the use of single-piece heat exchanger elements of great size will make cleaning very hard, more specially because the fans are on the roof and frequently hard to get at.

For these reasons, a further purpose of the invention is that of designing a ventilator whose parts to be cleaned may readily be taken to pieces, such pieces then being readily handled and, for this reason, readily cleaned.

This purpose is effected in that the heat recovery unit is made up of a number, for example two, three, four or six, of heat exchanger units, each designed as a separate body and designed for cross-over motion of the air currents through it, the heat exchangers having a prismatic form, for example in the form of plate-like heat exchangers, or such heat exchangers being in the form of pipe heat exchangers, which are placed radially with or without being diametral in relation to each other, in that the heat recovery unit furthermore has a core part, forming a part of the air ducting system and designed as a load-supporting part, for example with a six-sided cutline, which is placed in the middle of the overall ventilator structure and at the same height as the heat exchanger units and on the lower side is joined up with the input air duct, which is best coaxial in relation to it, and in that the heat exchanger units are placed on a load-supporting part of the apparatus which may have for example the core part with it.

The useful effect with such a further development of the invention is that cleaning may now be readily undertaken and, for this reason, the efficiency of the ventilator generally may be stepped up without making it more complex or higher in price; the heat exchange unit may be readily parted from the core part, forming the load-bearing part of the ventilator generally, and be put back on it. The heat exchanger units are, in this respect, of such a size that they may readily be taken off and taken down from the roof for cleaning where such cleaning work is most readily possible, using for example compressed air or a water jet.Furthermore, dependent on the ventilation effect, more or less heat exchanger units may be used, it being possible for example to have a six-sided core part, which, dependent with needs on the spot, may be used with two, three, four or six such units joined up to it. For this reason, on the one hand producing and, on the other hand, warehousing such ventilators is made simple and all needs may be taken care of.

In the accompanying figures some working examples of the invention will be seen.

Figure 1 is a diagrammatic side view of a first working example of the invention.

Figure 2 is a view on the same general lines as in figure 1, the structure being somewhat different in respect to details.

Figure 3 is a diagrammatic side view and section of a further, somewhat changed working example of the invention.

Figure 4 is a diagrammatic and partly cut away side view of a further working example of the invention.

Figure 5 is a diagrammatic view looking down on the structure of figure 4.

Figure 6 is a diagrammatic view looking down on the structure of figure5, this time with two heat exchanger units.

Figures 7 and 8 are views, on the same general lines as in figure 6, of somewhat changed forms of the ventilators of figures 5 and 6, having in one case three heat exchanger units and in the other case four units.

Figure 9 is a partly cut away and diagrammatic view of a further changed form of the ventilator of the invention, as seen from the side.

Figure 10 is a diagrammatic, plan view looking down on the system of figure 9.

Figure 11 is a view of a further somewhat changed form of the invention, as seen from the side, partly cut away and diagrammatically.

Figure 12 is a diagrammatic view, as seen in plan, of the ventilator of figure 11.

In the case of all working examples of the invention in the figures, it is a question of a roof ventilator (that is to say a ventilator running through and supported by a roof) for letting off air from, and the input of fresh air and heat into rooms of great size, the ventilator having in each case an air duct with its own fan for the output air current and an air duct for the input air current, together with a heat recovery unit responsible for heat exchange between the output and input air currents and which is made up of a ring-like (annular) plate heat exchanger, through which one of the two air currents goes in a radial direction in relation to the output air fan while the other air current is moved through it in an axial direction.

The plate heat exchanger is positioned between the roof foot support (used for fixing the ventilator to the roof of the room to be ventilated) and an inlet and outlet for the axial air current coming from and going into the outside atmosphere.

In the case of the working example of the invention to be seen in figure 1 , the ring-like plate heat exchanger 1 is placed between the roof foot support 2, which is fixed to the roof 3 of the room to be ventilated, and the fan or blower, producing the axial air current 5, and which is numbered 4. In the case of this working example of the invention the input air current is let in radially as arrowed at 6a, 6b into the ring-like heat exchanger and comes out of it again as marked by arrows 7a, 7b and the further arrows 8a and 8b, the air then moving into the room which is to be ventilated, while the output or waste air is aspirated so that it is moved along the directions marked by arrows 9a, 9b through the space under the roof or ceiling of the room 10 to be ventilated and then, still because of the aspirating effect, is moved generally axially (see arrows 1 a, 11 b) through the ring-like heat exchanger and is then forced outwards, again axially, as marked by arrows 5 out of the top of the ventilator into the outside atmosphere.This system to be seen in figure 1 has two fans: one fan or blower 4 for producing the output air current and a fan 12 for moving the input air current, the two fans being coaxial in relation to each other and being, in the present working example, radial fans. It is to be seen from the figure that the roof foot support 2 is, generally speaking, in the middle of the ventilator and on its top side or top end, furthest from the roof, has the ring-like heat exchanger 1 resting on it, said heat exchanger having radial inlets for input air moving in the directions marked by arrows 6a. On its side or end, furthest from the support 2, the plate heat exchange 1 has the housing resting on it, in which the outlet air fan 4 is put for forcing along the output or waste air so that such air comes out of the top end of the ventilator as marked by arrow 5.

The middle part of the plate heat exchanger has the outlet 13 (turned in the axial direction in a direction opposite to the motion of the waste or output air) for the input air, the plate heat exchanger opening into an input air duct 15 (running coaxially through the airway 14 within the support 2, and having its lower end running downwards into the room to be ventilated) so that, in the working example to be seen in the figure, at its lower end the input air fan 12 is supported.In place of this, the input air guide duct may have, at its lower end, further ducts for guiding or distribution of the input air; furthermore, the system may be so designed that the input air duct is joined at its lower end with an overhead air heater, responsible for a second stage of heating, the input air fan 12 not being present in such a case, because the overhead air heater will have its own fan or blower. In the working example of figure 1, the waste or output air is aspirated and taken in from the space under the ceiling (or under the roof) without being specially ducted.

A further form of the ventilator of figure 1 , to be seen in figure 2, is only changed to a small degree: In this case the foot support may be seen at 2a, while 3a is used for the roof of the room to be ventilated, that is to say to have stale air taken from it and fresh let into it. The duct 1 spa has the input air fan supported at its lower end or it may be joined up with ducting or with an overhead heater for the air, as has been noted as a possible system in connection with figure 1. This part of the system is not given in detail in the figure.In the case of the further form of the invention to be seen in figure 2, however, the output or waste air is not, in this case,-aspirated from an open space under the roof or ceiling, but is taken in by way of a header 16 with a ducting connection 1 7 so that, in this case, the stale or waste air is aspirated from a position under the roof of the room to be ventilated and is then guided by way of this header and pieces of ducting into the connection 17, directed towards the ring heat exchanger resting on the support 2a.

In the further form of the invention to be seen in figure 3, two ring-like plate heat exchangers 20, 21 placed one on top of the other or in tandem are used, of which the one (20) is positioned over the roof or floor 22 between support 23 and inlet 24 for the input air, whereas the other or lower heat exchanger 21 is positioned under the roof 22 of the room which is to be ventilated. The output air fan 25 is, in this case, placed between the two ring-like plate heat exchangers.The system is so designed that not only the heat exchanger 20, placed over the roof, but furthermore the heat exchanger 21 placed thereunder have the output or stale air moving through them radially while the input air is run through them in an axial direction; the output air comes into the lower heat exchanger (21) as marked by arrows 26 and comes out of the top heat exchanger as marked by arrows 27, while the input air, making its way from the top to the lower heat exchangers (20, 21) is run through a ring-like or annular space 30, in which the housing of the output or stale air fan is placed, such air then moving into the upper heat exchanger 20 as marked by arrows 28 and coming out from the lower heat exchanger as marked by arrows 31.The reader will be able to see from the figure that with this way of ducting the input air current and the output air current, the input air will undergo heat exchange on its way from the top heat exchanger to the lower heat exchanger or, putting it differently, it gets heat from the waste or stale air on its way through the output air fan. In this respect the input air fan may be placed over the top ring-like plate heat exchanger, although it is furthermore possible for it to be placed under the lower ring-like plate heat exchanger.The system is in any case, however, so designed that over the roof foot support 23 fixed to the roof 22 of the room to be ventilated, the upper heat exchanger 20 is placed, over which the inlet 24 for the inlet air will be seen, whereas the middle part of the ventilator is generally at and within the roof foot support, the output air 25 being within the ring-like space 30. The lower part of the ventilator has within it the lower plate heat exchanger 21 and the outlet opening 31 for the inlet air.In this case the ring-like space of the top plate heat exchanger, the housing of the outlet air fan and the ring-like space of the lower plate heat exchanger and, possibly, the inlet and the outlet openings for the inlet air are placed so as to be coaxial in relation to each other and forming together the middle part of the ventilator, which is used for the current of outlet or stale air moving as marked by arrows 32, 33, while the outer part, placed round this middle part, that is to say generally speaking the ring-space 30 with the two plate heat exchangers 20, 21, is generally used for the input air current only.

It will be seen on the one hand from the line-up and design of the parts of the ventilator of the present invention and on the other hand from the way in which the parts are to be seen in the drawing, that the separate parts of the ventilator may be unfixed from each other and the ventilator taken to pieces, the ventilator being made up of modular parts, or, putting it somewhat differently, some of the parts of the ventilator are standard parts which may be put together with other parts, different to those to be seen in figure 3, for making up different forms of ventilator and may be marketed separately for use.This way of piecing together the parts forming the overall ventilator, made up of a number of separate parts, furthermore makes it possible for (dependent on the conditions and design of a building which is to be ventilated) different forms of ventilator to be made up using the same, or generally the same, separate parts. In the system of figure 3, all parts of the ventilator are placed in a somewhat cubelike housing taking up little space.

The ventilator of figures 4 and 5 is so designed that the air is ducted in a direction as marked by arrows 101, under the effect of fan 102 (for the output air current) while input or fresh air is ducted in the direction marked by arrows 103.

Furthermore, this ventilator has a heat recovery unit, generally marked 104, and a heat exchanger between the output air current 101 and the input air current 103. This heat recovery unit has a heat exchanger system and an input air duct 105, designed running through the lower of the ventilator and into its middle part, through the support 106 so that its lower end is sticking outdownwards into the room 107 to be ventilated and which is shut off at the top by ceiling (or roof) 108.

The heat recovery unit 104 has a number of prismatic heat exchanger unit, which are separately designed as a number of bodies. In the working example of figures 4 and 5 the heat recovery part 104 has six heat exchanger units 109a, 109b, 109c, 109d, 109e and 109f, which, for their part, are made up of two parts, that is to say the heat exchanging part 110 itself and an air ducting part lila, 11 and 111 c. The heat exchanging part 110 in the narrow sense has the form of a cube and the overall system made up of parts110,111a,111band 111cisofsuchasize that it may readily be handled; the heat exchanger units may readily be taken off and moved clear of the roof and taken to a place where, for example by compressed air or using a water jet, they may be cleaned.The ducting part of each heat exchanger unit is made up of three funnel-like or cowl-like structures lily, 111 b and 111 c which, in each case (see figure 4) to be seen from side to have a trapezium-like outline while (see figure 5) when seen in plan view, they have right angled corners. It will be seen from figure 4 that these funnel-like or cowl-like structures ill a, 111 b and 111 c are, in each case, open in the inlet or outlet direction, that is to say the cowl ill b is open at 112b, cowl 111 c is open at 11 2c and, lastly, cowl 1 1 lea is open at 112a. On the opposite side and on their two long-sides, these cowl-like structures are shut off, the trapezium outline becoming broader towards the open side.The heat exchanger units of the system so detailed are best, furthermore, designed as cross-over current exchangers although, however, as was the case with working examples to be seen in the figures, they may be designed as plate heat exchangers or pipe heat exchangers.

The heat recovery unit furthermore has a middle core part 113, which is placed in the middle of the ventilator generally and it is generally at the same level as the heat exchanger units 1 09a to 109f. The core part 113 may be seen, more specially from figure 4 to have a part of the air ducting system and to be designed as a - load-bearing part. In the case of the working example to be seen in figures 4 and 5, as was the case with the other working examples to be seen in the figures so far, the core part will be seen in plan view to have the outline of a six-sided figure although naturally it may be of a different design.

The core part is fixed to the support 106 (see figure 6) and may, for example, be placed on top of it.

The heat exchanger units 1 09a to 1 09f may be undone from the supporting part of the ventilator, and in the working examples to be seen in the figures, this supporting part of the ventilator is formed by the core part itself. In this respect, the heat exchanger units are so placed on this supporting part (the core part) that they are diametrally opposite to each other or like the arms of a starfish. For this purpose, in the working examples to be seen, the heat exchanger units are each placed so that their side faces, for example side face 11 4a in figure 5, are resting flatly and fully against an opposite outer face 11 4b of the core part, said face 11 4b forming one of the sides of the six-sided outline of the core part.The heat exchanger units may, in this respect, be designed so that they may be undone from the core part using a high-speed fastener, although another sort of connection may be used if desired. In this respect, in addition, the system is so designed that the funnel-like or cowl-like structures lily, 111 b and 111 c are supported on and fixed to the boxlike part 110 of the nearby heat exchanger part, that is to say, in each case, on its side (turned away from the core part) 110 and on its sides facing away from the waste air outlet 11 Ob and the fresh air inlet 11 Oc. In this respect, the core part has on the sides facing the open sides of the funnel-like or cowl-like structures, in each case, a duct 11 2d, 11 2e, joined up with this side, and which at its opposite side is joined up with the duct for the outlet or inlet air current.

As will have been seen, the same core part or another core part of the same design, which is best joined up with the inlet air duct 105 (running through the roof foot support 106) and the outlet air head 11 5 coaxially, may be joined up with a different number of heat exchanger units and furthermore with a different line-up between the parts. In the case of the working example of figure 6, the ventilator has two heat exchanger units 120, 121, which are placed at two opposite side faces 120a and 120b of the core part 122 (which is in the form of a six-sided figure) diametrally opposite to each other.In the line-up of figure 7, three heat exchanger units 123, 124 and 125 will be seen, which are placed on three side faces 123a, 124a and 125a, having an angle between them of 1200 about the axis of the ventilator, such side faces being faces of a six-sided core part 126.

The ventilator of figure 8 has four heat exchanger units 127, 128, 129 and 130 which are placed, in each case, in groups of two (that is to say the groups 127, 130 and, on the other hand, 128, 129), the two heat exchanger units of each group of two, that is to say the two units 127, 130 on the one side and 128, 129 on the other side, being fixed to the other side in each case on nexttogether side faces 127a, 130a on the one side and, in the other case, 1 28a, 1 29a on the other side of a core part having a six-sided outline 1 31.

Between the two groups-of-two 127, 130 and, in the other case, 128, 129, in each case one side face 131 a and 131 b in the other case of the core part is kept free. In the case of six heat exchanger units we will then have the line-up to be seen in figure 5 and it will be seen from figure 4 that the output air current is firstly forced through the airway 11 6 within the roof foot support and then, after being turned through an angle of 900 two times it is forced through the heat exchanging part 110 in question of the heat exchanger unit while moving in an axial direction towards the outlet air head as arrowed 101 a and nextly, the air, after being changed in direction by 900, again will go in an axial direction (see arrow 101 b) through the outlet air header into the outside atmosphere, while the inlet air current is forced through its heat exchanging part 110 of the heat exchanger unit in the radial direction (see arrow 103a) and is then moved, after being changed in direction by 900, into the inlet air duct 105, from which it comes on its way into the room to be ventilated.

In the case of the working example of figures 9 and 10, the heat exchanging effect is made greater, that is to say made two times as great.

For this purpose, heat recovery unit 140 is made up of two groups 1 32 and 144 of heat exchanger units which, in the direction of current through the ventilator (see arrows 141 and 142) are placed one after the other or in tandem and, from the point of view of their geometry, are placed one over the other. These groups 143, 144 of heat exchanger units may have, as in the case of the working examples noted so far, for example two, three, four or six heat exchanger units. The heat exchanger units of the two groups answering to each other, for example the heat exchanger units 1 43a of group 143 and the heat exchanger unit 1 44a of group 144 are, in this case, placed in tandem in relation to each other.Core part 145 is in this case a two-floored structure and its axial size is two times greater, that is to say in line with the height of the two heat exchanger units placed one above the other, as will be seen in figure 9. In figure 10 we have an example of the invention with four heat exchanger units 1 43a, 1 43b, 1 43c, 1 43d and 1 44a, 1 44b, 1 44c and 1 44d for each of the two groups 143, 144. The core part is numbered 142 and has two times the normal height, that is to say twice that of the system of figure 4, the inlet air opening 146 stretching only over a part of the height of the core part and it is possible to see that this inlet opening for inlet air 146 is in this case on the core part, it stretching in this working example only over half of the height of this core part but, however, over its full breadth.

In this case, the outlet or stale air current is moved in an axial direction (see arrow 141a and 141b) through the tandem-circuited heat exchanger units one after the other, the outlet air current furthermore being changed in direction at different points as was the case with the forms of ventilator noted earlier. The inlet air current goes through the tandem-circuited heat exchanger units 1 43a and 1 44a one after the other in a radial direction (see arrows 1 42a and 142b), said inlet air current, after coming out of the first heat exchanger unit and before moving into the next or second heat exchanger unit 144a, being changed in direction two times in the parts 1 42c and 142d.In this case the openings of the funnel-like or cowl-like structures 147, 148, pointing away from the inlet air duct, are directed towards each other and joined up together, see points 1 47a and 148a.

In a further working example of the invention to be seen in figures 11 and 12, it is possible, for example in hot weather in which the room is to be cooled, for the inlet air not to be forced through by way of the heat exchanger elements so that it is not heated by the outlet or stale air. In this case as well, we have two heat exchanger units 150, 151, placed one on top of the other, that is to say joined up in tandem, the units being so designed and so placed in relation to each other as was made clear in connection with figure 9; in this case as well, the core part 1 52 has two "floors" its height h being roughly twice the size of the height in examples of the invention noted so far, see figures 4 to 8; while the inlet air opening has the same breadth b of the core part, its height c is only half the size of the height of the core part. This inlet air opening 1 53 lets in the inlet air as arrowed at 154, the air going straightway, that is to say without going through the heat exchanger units, to the outlet opening 1 55 at the end of the inlet air duct 1 56. The direction of the outlet or stale air is, as was the case with the working example of figures 9 and 10, through the two heat exchanger units 150, 151, see arrows 157, the air moving in an axial direction. The design is furthermore best made with direction changing, rate controlling, or shut-off parts such as valves, which are not to be seen in detail in the figures, such parts being used for branching off the inlet air current coming from the inlet opening, before it is let into the heat exchanger units and forcing such air straightway into the inlet air duct. In this case, the inlet air is not heated by the stale or waste air, although it is naturally possible for the system to be so designed that, for example in winter, there is a cross-over motion of the air currents and the inlet air is moved past the waste or stale air, for example as in the system of figures 9 and 10. In cases in which the inlet air is to be forced straightway to the outlet opening, the system may be so designed that the heat of the waste or stale air is taken up in some other way and, if desired, made use of in some way.

Claims

1. A roof ventilator for ducting an input air current into a room, for input of heat to said room and for ducting an air output current therefrom, having an air duct, together with a fan, for the output air current, and an air duct for the input air current, and with a heat recovery unit for causing heat exchange between the output air current and the input air current, characterized in that the heat recovery unit is made up of at least one pipe heat exchanger or a ring-like plate heat exchanger designed for motion of one of the two air currents through it radially with respect to the output air fan and for motion therethrough of the other air current in an axial direction, the heat recovery unit being made up, for example, of two such heat exchangers placed in tandem, and into which, for example, the input air current is radially ducted and let out of it, for example axially, while the output air current is ducted axially through the ring-like plate heat exchanger and is axially ducted out of the ventilator, and the heat recovery unit is placed between a roof support, used for fixing the ventilator to the roof of the room, and the inlet or outlet for the axial air current out of or into the atmosphere, for example out of the fan producing the axial air current.

2. A roof ventilator as claimed in claim 1, characterized by a fan, designed, for example as a radial fan for acting on the output air current and a fan, designed, for example as a radial fan, for the input air current, the two fans being coaxial in relation to each other.

3. A roof ventilator as claimed in claim 2, characterized in that the roof support, fixed on the roof of the room to be ventilated, is placed generally in the middle of the ventilator and at its top side, facing away from the roof has the ringlike plate heat exchanger, with radial inlets for the input air, supported on it, and the plate heat exchanger has, on its side facing away from the support, resting on it a housing for the output air fan with the axially directed outlets for the output air, and its middle part is used for supporting the outlet, directed in an axial direction in the opposite direction to the output air, for the input air, it opening into an input air duct running through the support coaxially, the input air duct having its lower end running out into the room which is to be ventilated and this input air duct may have, supported on its low end for example, an input air fan with its housing and/or may be joined up with ducts pa,rts for further ducting of the input air and/or may be joined up with an overhead air heater, having the function of a second stage air heater and/or aspirating the free air near and under the roof of the room.

4. A roof ventilator as claimed in claim 3, characterized in that the output air is aspirated into a header placed under the roof of the room to be ventilated and is ducted by the header and by ducts to an opening, joined up with the ring-like plate heat exchanger, through the roof support of the ventilator.

5. A roof ventilator as claimed in claim 1, having two plate-like heat exchangers placed in tandem, characterized in that the one heat exchanger is positioned over the roof between the roof support and the inlet for the input air and the other heat exchanger is placed under the roof of the room to be ventilated and, more specially, the output air fan is placed between the two ring-like heat exchangers, and the input air fan may be positioned over the top or under the lower ringlike plate heat exchanger.

6. A roof ventilator as claimed in claim 5, characterized in that not only the heat exchanger placed over the roof, but furthermore the heat exchanger under the roof are designed for radial motion of the output air current through them and for motion of the input air current axially through them, and the output air current goes into the lower heat exchanger into and out of the top one and the input air in the top heat exchanger goes into and out of the lower one, while the input air is on its way from the top heat exchanger to the lower heat exchanger while undergoing heat exchange with the output air moving through the output air fan, this taking place for example because of the air's moving through a ring-like space, in which the housing of the output air fan is placed.

7. A roof ventilator as claimed in claim 5 or claim 6, characterized in that over the roof support, placed on the roof of the room to be ventilated, the top ring-like heat exchanger is placed, over which the inlet for the input air is placed, in that the middle part of the ventilator is generally at the roof support and has within it the output air fan and in that the lower part of the ventilator has within it the lower ring-like or annular plate heat exchanger and the outlet for the input air, in which respect the ring-like space at the top plate heat exchanger, the housing for the output air fan and the ring-like space of the lower plate heat exchanger and possibly the inlet end outlet for the input air are preferably placed coaxially in relation to each other for forming the middle part of the ventilator, through which, more specially, the output air current is generally axial, while the circumferential part, skirting the middle part, is generally designed for the input air.

8. A roof ventilator as claimed in anyone of claims 5 to 7, characterized in that all parts of the ventilator are nested together like a cube in a housing.

9. A roof ventilator as claimed in anyone of claims 5 to 8, characterized in that the heat recovery unit is made up of a number, for example two, three, four or six heat exchanger units, each designed as a separate body and designed for cross-over motion of the air currents through it, the heat exchangers having a prismatic form, for example in the form of plate-like heat exchangers, or such heat exchangers being in the form of pipe heat exchangers, which are placed radially with or without being diametral in relation to each other, in that the heat recovery unit furthermore has a core part, forming a part of the air ducting system and designed as a load-supporting part, for example with a six-sided outline, which is placed in the middle of the overall ventilator structure and at the same height as the heat exchanger units and on the lower side is joined up with the input air duct, which is best coaxial in relation to it, and in that the heat exchanger units are placed on a load-supporting part of the apparatus which may have, for example the core part within it.

10. A roof ventilator as claimed in claim 9, characterized in that the heat exchanger units are, in each case, made up of the heat exchanging part itself and an air ducting part, and, preferably, the heat exchanging parts themselves have, in each case, the form of a cube and the heat exchanger units are of such a size that they may readily be handled, whereas the air ducting part for example of each heat exchanger unit may be made up of three funnel or cowl structures with a trapeziumlike outline as seen from the side and a right angled outline as seen in plan view, which, in each case, are open in the direction of air inlet or air outlet and which on the opposite side, and on the long-sides are shut off, and the trapezium becomes broader towards the open side and which on the cube of the heat exchanging part in question are in each case placed on its side, turned away from the core part, and on its sides turned towards the output air outlet and the input air inlet.

11. A roof ventilator as claimed in claim 10, characterized in that the core part has, on the sides turned towards the open sides of the funnel or cowl structure, in each case an air duct joined up with this side, which on its opposite side is joined up with the duct for the output air in the one case and for the input air in the other case.

12. A roof ventilator as claimed in anyone of claims 9 to 11, characterized in that the core part is fixed to the roof support by being placed on top of it for example and in that the heat exchanger units, in each case, have one of their side faces resting flatly and fully against a facing outer face of the core part and answering to one of the sides of the six-sided figure outline, and they are preferably fixed to the core part with high-speed fasteners.

13. A roof ventilator as claimed in any one of claims 9 to 12, characterized in that in the case of two such heat exchanger units, the said units are placed on two opposite side faces of the core part, which has a six-sided outline, diametrally opposite to each other, whereas in the case of three heat exchanger units the said units are fixed on three side faces, spaced by an angle of 1 200 in relation to each other of the core part which has a sixsided outline, or in the case of four heat exchanger units, in each case in groups of two, the two heat exchanger units of each group of two are fixed to groups of side faces, next to each other, of the core part which has a six-sided outline, and between the two groups of two there is a side of the core part without any heat exchanger unit, or, lastly, in the case of six heat exchanger units such units are fixed to separate ones of the sides of the core part which has a six-sided outline.

14. A roof ventilator as claimed in any one of claims 9 to 13, characterized by its being designed for ducting the output air current firstly through the support, then, after being changed in direction two times through 900, through the heat exchanging part of the heat exchanger unit in an axial direction towards the output air head and then after being changed in direction by 900 two times is ducted upwardly in an axial direction through the output air head, while the input air current is ducted through its heat exchanging part of the heat exchanger unit in a radial direction and after being changed in direction by 900 is ducted into the input air duct by which it is ducted into the room to be ventilated.

1 5. A roof ventilator as claimed in any one of claims 1 to 14, characterized in that the heat recovery part is made up of two groups of heat exchanger units, placed in tandem and one on top of the other geometrically, such groups being made up in each case of 2, 3, 4 or 6 such units, and the heat exchanger units, answering to each other, of the two groups are placed in tandem and are best designed for axial motion of the output air current through them one after the other in an axial direction, and the core part has a two-floored or two-storeyed axial size.

1 6. A roof ventilator as claimed in claim 15, characterized by its being designed for ducting the input air current radially through the heat exchanger units, placed in tandem, one after the other, and the input air current after coming from the first heat exchanger unit and before being inlet into the next heat exchanger unit, is changed in direction twice by 900, and, for example the openings of the funnel or cowl structure, pointing away from the inlet air duct may be joined together and directed towards each other and the inlet opening for the input air may be on the core part and stretching over only a part of the height, for example only for half its height, but over the full breadth.

17. A roof ventilator as claimed in any one of claims 9 to 16, characterized by its being designed for ducting the input air directly by way of the heat exchanger units to the outlet opening for the input air by using for example valves or the like for changing the direction of the air current and with whose help the input air, coming from the inlet opening, is branched off before being let into the heat exchanger unit and is ducted directly into the input air duct.

18. A roof ventilator for ducting an input air current into a room, for input of heat to said room and for ducting an air output current therefrom, the ventilator having an air duct, together with fan means for the output air current, an air duct for the input air current, and a heat recovery unit for causing heat exchange between the output air current and the input air current, the heat recovery unit comprising at least one heat exchanger designed for motion therethrough of one of the air currents radially with respect to the output air fan, and for motion therethrough of the other air current in an axial direction, and being positioned between a roof support for fixing the ventilator to the roof of the room, and the inlet or outlet for the axial air current out of or into the atmosphere.

19. A ventilator substantially as described above with reference to and as illustrated in the accompanying Figures 1 and 2.

20. A ventilator substantially as described above with reference to and as illustrated in the accompanying figure 3.

21. A ventilator substantially as described above with reference to and as illustrated in the accompanying figures 4 and 5.

22. A ventilator substantially as described above with reference to and as illustrated in the accompanying figure 6.

23. A ventilator substantially as described above with reference to and as illustrated in the accompanying figures 7 and 8.

24. A ventilator substantially as described above with reference to and as illustrated in the accompanying figures 9 and 10.

25. A ventilator substantially as described above with reference to and as illustrated in the accompanying figures 11 and 12.

26. Any novel subject matter or combination including novel subject matter herein disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.