GB2079852A - Ventilator fans - Google Patents

Abstract

A ventilator fan comprises an electric motor (10) and an axial flow impeller (14) for extracting hot smoke, mounted within a tubular ventilator housing (15) of sheet steel. The drive motor (10) and the impeller (14) are coaxially mounted in the housing (15) and the impeller (14) is driven directly by the drive motor (10). The motor is housed in a thermally insulated chamber (17) which contains at least one cooling air passage through (19) which air is drawn by a radial flow fan (28) via a passage (20). The cooling air leaves via a passage (21). The motor chamber (17) is formed by an inner cylinder (22) comprising a double jacket (23, 24) and an end cover (25), each of which is lined with thermally insulating material (26, 27). The ventilator can be used in a tubular smoke extraction passage. <IMAGE>

Description

SPECIFICATION Fire gas ventilator The invention relates to a fire gas ventilator having an electric drive motor and an axial impeller driven thereby within an especially tubular ventilator housing.

Fire gas ventilators or equally what are called smoke extractor ventilators are used for the extraction of smoke from parts of buildings in the case of fire, as members of mechanical smoke extraction equipment. Special demands are made of such fire gas ventilators as regards the temperature stability and the duration of operation under the action of temperature. Under the special temperature loading in case of fire a duration of use is to be achieved which reliably corresponds to the required fire resistance duration, for example of 90 minutes, this at a temperature loading of 6000 C. Then it is ensured that in case of fire the fire gas ventilator is suitable for smoke extraction during the said time duration of 90 minutes at a smoke gas temperature of 6000 C.

Fire gas ventilators are known in which - in order to fulfil the said prerequisites -- the electric drive motor lies relatively far away from the axial impeller and works upon the latter by means of a transmission in the form of a belt transmission which in turn is more or less adequately thermally insulated and protected, since it leads into the smoke gas region. Fire gas ventilators of this kind are quite large in construction as regards the external dimensions. Moreover they are relatively complicated and dear, since as regards all individual components they are designed specially so that each component independently conforms with the high requirements of the initially mentioned kind.Therefore such fire gas ventilators are extraordinarily dear, which in the case of the question whether purely by way of precaution for the case of a fire such special fire gas ventilators should be installed at all, has frequently finally very often given the indication to abstain from instailation.

It is the problem of the invention to produce a fire gas ventilator of the initially stated kind which is of the most simple, cheap and at the same time space-saving and compact configuration possible and, if possible using simple components which are used as series parts in the production of normal axial fans, at the same time reliably conforms with the high requirements regarding heat loading and duration of use in case of fire.

In a fire gas ventilator of the initially stated kind in accordance with the invention the problem is solved in that the drive motor and the axial impeller are grouped coaxially within the ventilator housing and the axial impeller is seated on the motor shaft of the drive motor and driven directly by the latter. It is especially advantageous in this case if the drive motor is arranged within a thermally insulated motor chamber separated from the air current, which chamber comprises at least one internal cooling air passage which is conducted to the exterior through preferably lateral cooling air passages opening into it. The motor chamber is advantageously formed by an internal cylinder with double jacket and axial end lid on the suction side, which are each lined with insulating material. There is a forced air flow through the motor chamber.

A fire gas ventilator of such design is relatively simple and favourable of cost. It has very compact small dimensions and can be inserted like a conventional axial fan directly for example in a tubular smoke extraction passage. It is especially advantageous that due to the forced air throughflow a highly effective cooling of the electric drive motor is achieved so that the latter can be designed as a standard motor, thus no electric motor of special construction is necessary, for example with water-cooled or oil-cooied bearings. The excellent cooling also achieves the object that normal sheet steel of St 37 quality can be used and worked, for example welded, as material so that thus expensive highly refractory materials, with the difficulties of working, are unnecessary.Nonetheless the fire gas ventilator according to the invention is capable fully of conforming with the requirements to be made for safety reasons, that is to say in the case of fire of reliably withstanding a temperature loading at temperatures of 6000C over a duration of use of at least 90 minutes, without the occurrence then of damage, faults or even failure caused by material for example. Rather the functional capacity is reliably guaranteed, as confirmed incidentally by experiments and safety acceptance tests.

The invention is explained in greater detail below by reference to examples of embodiment shown in the drawings, wherein:- FIGURE shows a diagrammatic lateral elevation, partially in section along the line I-I in Figure 2, of a fire gas ventilator according to a first example of embodiment, FIGURES 2 and 3 show diagrammatic sections along the lines Il-Il and Ill-Ill respectively in Figure 1, FIGURE 4 shows a diagrammatic partially sectional lateral elevation of a part of a fire gas ventilator according to a second example of embodiment.

The fire gas ventilator as illustrated in Figures 1-3 comprises an electric drive motor 10 which is formed as a standard motor of foot-mounted construction and is for example a three-phase current squirrel-cage motor. From the left end of the motor housing 11 in Figure 1 the driving motor shaft 12 protrudes to the left in Figure 1 with shaft stub on which a hub 13 is held fast in rotation by axial securing means (not shown further). The drive motor 10 serves to drive an axial impeller 14 of the ventilator within a tubular ventilator housing 1 5 of sheet steel with flanges 16 welded on both sides.

The drive motor 10 and the axial impeller 14 are grouped coaxially within the ventilator housing 1 5. The axial impeller 14 is fitted through the hub 1 3 directly on to the motor shaft 1 2 and is driven directly by the drive motor 10, thus without need for interposed transmission means.

The drive motor 10 is arranged within a special motor chamber 1 7 which is separated from the flow of fire gas, which proceeds in the case of operation in the direction of the arrows 18 within the ventilator housing 15, and is thermally insulated. The motor chamber 1.7 contains an inner cooling air passage 1 9 which is directed axially and approximately annularly surrounds the motor housing 11. The inner cooling air passage 1 9 is conducted to the exterior through lateral cooling air passages 20 and 21 which open into it.

Of these passages the one cooling air passage 20 forms the entry passage (Figure 2) and the other the exit passage (Figure 3). Both passages have approximately rectangular cross-section.

The motor chamber 17 is formed by an inner cylinder 22 with double jacket, formed from inner jacket 23 and outer jacket 24 concentric therewith, and an axial end cover 25 on the suction side. The interspace between the inner jacket 23 and the outer jacket 24 is lined with thermally insulating material 26. Furthermore the end lid 25 of somewhat cap form is internally lined with the same insulating material 27. In this way thus the motor chamber 1 7 and the drive motor 10 situated therein are insulated and protected against the high temperatures which prevail when the motor is switched on due to the fact that then very hot fire gas is conveyed axially by means of the axial impeller 14 through within the ventilator housing 15, namely between the latter and the inner cylinder 22, as indicated by the arrows 1 8.

The motor chamber 17 is ventilated by forced throughflow. For this purpose a directly driven cooling air impeller 28, which is situated within the motor chamber 17, formed especially as radial impeller and guarantees high power for forced throughflow ventilation, is seated on the hub 13 and thus on the motor shaft 12. By means of this cooling air impeller 28, fresh cooling air free from fire gas is drawn from the exterior in the direction of the arrows 29 (Figure 2) approximately tangentially to the motor housing 11 through the cooling air entry passage 20 into the inner cooling air passage 1 9.The cooling air then in axial flow as indicated by the arrows 30 sweeps over the motor housing 11 and after passing the inner cooling air passage 19 and sweeping over the motor housing 11, with corresponding removal of the internal lost heat of the drive motor 10 and the heat supplied from the exterior, is conducted away in the direction of the arrows 31 by way of the cooling air outlet passage 21 (Figure 3), which likewise extends approximately tangentially to the motor housing 11. The entry passage 20 and the exit passage 21 are conducted to the exterior through the ventilator housing 1 5 as separate passages, so that from an extraneous side cold cooling air free from fire gas can enter in the direction of the arrows 29 and in the exit region the heated cooling air can escape again to the exterior in the direction of the arrows 31.

As may be seen especially from Figure 1, the cooling air exit passage 21 in the axial direction of the drive motor 10 directly adjoins the cooling air entry passage 20 placed before it. For both a common passage jacket 32 is provided which is divided by means of a partition 33. The passage jacket 32 has a rectangular form seen from above (Figure 1). In the cross-sectional region which is defined by the left part of the passage jacket 32 ih Figure 1 and by the partition 33, the outer jacket.

24 and also the inner jacket 23 of the inner cylinder 22 are closed over a relatively great axiar length, measured from the partition 33 to the left in Figure 1, and on the left in Figure 1 only a small window 34 is open in the inner jacket 22, which transmissively connects the cooling air exit passage 21 with the inner cooling air passage 1 9.

The window 34 lies close to the left end of the inner cylinder 22 in Figure 1 and in the view according to Figure 1 permits a view of the cooling air impeller 28 and a part of the drive motor 10.

For the sake of greater clarity, of that region on the left which is defined by the passage jacket 32 and the partition 33, that part which is closed is marked by a cross.

The wall cf the cooling air entry passage 20 on the right in Figure 1 (Figure 2) is thermally insulated at least where this wall does not adjoin the partition 33. For thermal insulation there serves a double jacket which firstly is formed on the exterior by the part of the passage jacket 32 on the right in Figure 1 , and also by an inner jacket 35, the inter-space between the two being filled with thermally insulating material 36.

The motor chamber 17 is narrowed in nozzle manner in the region of the cooling air entry passage 20 and in the region of the cooling air exit passage 21. For this purpose within the motor chamber 1 7 on the right in Figure 1 and in the right end region of the drive motor 10 there and on the left in Figure 1 and in the left end region of the drive motor 10 there, there are arranged a disc 38 shaped into an axial entry nozzle 37 and a disc 40 shaped into an axial exit nozzle 39 in the same direction. The window 41 of the cooling air entry passage 20 defined by the inner jacket 35 and the partition 33 and visible in plan view in Figure 1 permits a view of the disc 38 there. Through the left window 34 in Figure 1 there is seen inter alia the left disc 40 placed there.

The cooling air entry passage 20 (Figure 2) opens approximately in the right axial end region of the drive motor 10 in Figure 1 into the inner cooling air passage 1 9 concentric with the drive motor 10. The outward opening of the cooling air exit passage 21 on the left in Figure 1 takes place approximately at the axial end region of the drive; motor 10 on the left in Figure 1. Where the cooling air exit passage 21 merges into the inner cooling air passage 19 there is arranged a special nose 42 which extends axially parallel and approximately over the axial course of the exit nozzle 39 (Figure 3). This nose 42 is also seen through the window 34 in Figure 1.The nose 42 imparts to the inner cooling air passage 1 9 in its end region an at least approximately spiral-shaped passage course, as may be seen from Figure 3, so that at this end region the cooling air impeller 28 can be formed as a radial impeller and is especially effective.

The drive motor 10 is secured with its diagrammatically indicated feet on a footplate 43 which in turn is secured according to a secant of a circle on the inner jacket 23 of the inner cylinder 22. The interspace formed between the side of the footplate 43 facing away from the drive motor 10 and the inner jacket 23 is completely filled with insulating material 44 in order to ensure reliable insulation here again and to prevent a possible build-up of heat. Figures 1 and 2 show that both the cooling air entry passage 20 and the cooling air exit passage 21 are aligned at least approximately at right angles to the plane of the footplate 43.

The ventilator housing 1 5 and the doublewalled inner cylinder 22 with end lid 24 consist of normal sheet steel of St 37 quality. The same also applies to the walls of the two cooling air passages 20 and 21.

At the axial end pointing towards the axial impeller 14 the inner cylinder 22 is externally provided with a heat protection 45, especially against radiation heat (Figure 1). The heat protection 45 has an asbestos panel 46 covering the axial end, which is secured for example by means of a flange 47 to the inner cylinder 22.

As indicated in chain lines in Figure 1, the asbestos panel 46 can also be covered on the side facing the axial impeller 14 by for example a thin cover plate 48 which can serve as protection and also as reflection plate.

In the second example of embodiment shown in Figure 4 it is merely indicated diagrammatically that in the axial zone outside the double-walled inner cylinder a directly driven additional cooling blade 51 is arranged on the hub 13 and thus on the motor shaft 12 and in this region effects an additional cooling of the drive motor 10. The constructional configuration of the cooling blade 21 can be of many kinds. In the example of embodiment according to Figure 4 as shown the cooling blade 51 consists simply of a disc 52 with radial flanges 53 seated on the right side thereof in Figure 4.

If in the case of a fire the fire gas ventilator is switched on for smoke extraction, the very hot fire gas is conducted away through the ventilator housing 1 5 by means of the rotating axial impeller 14. According to the test certificate of the Technical Supervision Board, the fire gas ventilator as explained withstands a temperature of 6000C for at least 90 minutes without detriment or even complete failure of the functional capacity. The ventilator housing 1 5 is constantly sealed in this case. The danger of escape of fire gases does not exist. There is also no danger of critical deformations under these temperature influences. The very simple and favourably priced configuration of the fire gas ventilator as described is especially advantageous.

In place of its individual components being made from expensive and expensively processed highly refractory material, all essential parts consist of normal sheet steel of St 37 quality. Thus by its construction the axial ventilator is of conventional kind. Due to the specially insulated and forcedflow ventilated inner cylinder 22 in which the drive motor 10 is installed, with other described advantages the object is achieved that at the stated heat loading in the case of fire a duration of use in conformity with the required fire resistance duration is reliably guaranteed, for example a duration of use of 90 minutes. The forced throughflow ventilation and special inner cooling take place, as already explained, by the cooling air impeller 28 driven directly by the drive motor 10.

By means of this impeller cold air conducted in a completely separate flow is sucked from the exterior in the direction of the arrow 29 through the thermally insulated cooling air entry passage 20 into the motor chamber 1 7. The cooling air is conducted by means of the entry nozzle 37 at high speed in the axial direction along the motor housing 11 to the exit nozzle 39.The cooling air withdraws the lost heat occurring in operation from the drive motor 10 and further prevents unacceptable heating of the drive motor 10 by the heat which the fire gas delivers to the encapsulated inner cylinder 22 in passage through the ventilator housing 1 5. The thermal insulation of the inner cylinder here contributes substantially to the relatively low temperature in the region of the motor chamber 1 7. The heated cooling air is conducted through the exit passage 21 out of the motor chamber 1 7 and to the exterior.The heat protection 45 with asbestos panel 46 and cover plate 48 protects against unacceptable heating of the encapsulated inner cylinder 22 on the left axial side in Figure 1, namely from the axial impeller 14 with hub 1 3. If necessary the cooling blade 51 can be provided in accordance with the second example of embodiment according to Figure 4 as additional heat protection. Due to this good cooling the simple and space-saving configuration of the drive motor with directly driven axial impeller 14 is possible, this using parts which come into use in normal axial fans. The electric drive motor 10 can also be a standard massproduced motor the bearings of which are lubricated for example with hot bearing grease.

The otherwise present fan pertaining to the motor at the end opposite to the motor shaft 12 can even be omitted, as shown by Figure 1. Thus in all a highly effective fire gas ventilator is produced which is extraordinarily favourably priced and compact and at the same time satisfies all requirements for the case of fire to a high extent.

Claims (19)

1. Fire gas ventilator, having an electric drive motor and an axial impeller driven by it within an especially tubular ventilator housing, characterised in that the drive motor (10) and the axial impeller (1 4) are grouped coaxially within the ventilator housing (15) and the axial impeller (14) is seated on the motor shaft (12, 13) of the drive motor (10) and driven directly by the latter.

2. Fire gas ventilator according to Claim 1, characterised in that the drive motor (10) is arranged within a thermally insulated motor chamber (17) separated from the air current (arrows 18), which chamber contains at least one internal cooling air passage (19) which is conducted to the exterior through preferably lateral cooling air passages (20, 21) which open into it.

3. Fire gas ventilator according to Claim 2, characterised in that the motor chamber (17) is formed by an inner cylinder (22) with double jacket (23, 24) and axial end cover (25) on the suction side, each of which is lined with insulating materials (26, 27).

4. Fire gas ventilator according to Claim 2 or 3, characterised in that there is forced air throughflow through the motor chamber (17).

5. Fire gas ventilator according to Claim 4, characterised in that on the motor shaft (12, 13) there is seated a directly driven cooling air impeller (28), preferably a radial impeller, arranged within the motor chamber (17), by means of which cooling air can be drawn preferably approximately tangentially to the housing (11) of the drive motor (10), through a cooling air entry passage (20, arrows 29) into the inner cooling air passage (19) and after axially passing the inner cooling air passage (19, arrows 30) and sweeping over the drive motor (10), can be discharged through a cooling air exit passage (21, arrows 31), preferably likewise approximately tangentially.

6. Fire gas ventilator according to Claim 5, characterised in that the cooling air exit passage (21) in the axial direction of the drive motor (10) directly adjoins the preceding cooling air entry passage (20) and in that the wall of the cooling air entry passage (20) is thermally insulated at least in the region not adjoining that of the cooling air exit passage (21), especially comprises a double jacket (32, 35) with insulating material (36) therein.

7. Fire gas ventilator according to one of Claims 1-6, characterised in that the motor chamber (17) is narrowed in somewhat nozzle manner (37 and 39) in the region of the cooling air entry passage (20) and in the region of the cooling air exit passage (21).

8. Fire gas ventilator according to Claim 7, characterised in that within the motor chamber (17) a disc (38) shaped into an axial entry nozzle (37) is arranged in the region of the cooling air entry passage (21) and a disc (40) shaped into an axial exit nozzle (39) in the same direction is arranged in the region of the cooling air exit passage (21).

9. Fire gas ventilator according to one of Claims 1-8, characterised in that the cooling air entry passage (20) opens approximately in the one axial end region of the drive motor (10) and the cooling air exit passage (21) opens in the opposite axial end region of the drive motor (10) into the inner cooling air passage (19) concentric with the drive motor (10).

10. Fire gas ventilator according to one of Claims 1-9, characterised in that approximately in the region where the cooling air exit passage (21) merges into the inner cooling air passage (19) there is arranged a nose (42) extending parallel with the axis and approximately over the axial course of the exit nozzle (39) there, which nose imparts an at least approximately spiral passage course to the cooling air passage (19).

11. Fire gas ventilator according to one of Claims 1-10, characterised in that the drive motor (10) is formed as a standard motor of footmounted formation and secured with its feet on a footplate (43) which in turn is secured along a secant of a circle on the inner cylinder (22, 23).

12. Fire gas ventilator according to Claim 11, characterised in that the cooling air entry passage (20) and the cooling air exit passage (21) are directed at least approximately at right angles to the plane of the footplate (43).

13. Fire gas ventilator according to Claim 11 or 12, characterised in that the interspace between the side of the footplate (43) remote from the drive motor (10) and the inner cylinder (22, 23) is completely filled out with thermally insulating material (44).

14. Fire gas ventilator according to one of Claims 1-13, characterised in that the ventilator housing (15) and/or the double-walled inner cylinder (22) with end cover (25) are formed from sheet steel of St 37 quality.

15. Fire gas ventilator according to one of Claims 1-14, characterised in that the doublewalled inner cylinder (22) externally has a heat protection (45) against radiation heat on the axial end facing the axial impeller (14).

1 6. Fire gas ventilator according to Claim 15, characterised in that the heat protection (45) comprises an asbestos panel (46) covering the axial end.

1 7. Fire gas ventilator according to Claim 16, characterised in that the asbestos panel (46) is covered by a cover plate (48) on the side facing the axial impeller (14).

18. Fire gas ventilator according to one of Claims 1-17, characterised in that in the axial region outside the double-walled inner cylinder (22) a directly driven additional cooling blade (51), for example a disc (52) with radial flanges (53), vanes or the like, is arranged on the motor shaft (12) or the impeller hub (13) seated thereon.

19. Fire gas ventilator substantially as described herein with reference to the accompanying drawings.