WO1993002291A1

WO1993002291A1 - Axial fans

Info

Publication number: WO1993002291A1
Application number: PCT/GB1992/001265
Authority: WO
Inventors: Richard John Isaac
Original assignee: Richard John Isaac
Priority date: 1991-07-16
Filing date: 1992-07-13
Publication date: 1993-02-04
Also published as: DE4292333T1; GB9115348D0; GB2272487A; GB9400700D0; GB2272487B

Abstract

For facilitating cleaning and servicing of a fan, specifically a cased axial fan or a plate mounted fan fitted in ductwork in an extraction system, the fan casing (10) is mounted between flanged end members (22) at an interruption in the ductwork (12) to be partially releasable and thereby capable of withdrawal, as by pivotal movement about a hinge (24), to an accessible position in which it remains attached to and supported by the ductwork.

Description

Axial fans

This invention relates generally to axial fans, in particular of the cased axial type or the plate mounted type, generically referred to herein and in the appended claims as axial fans of the type described.

Fans of the type described are commonly employed in industrial and catering establishments for the extraction of air, dust, fumes, cooking vapours, odious and/or hot gases, steam and the like. The invention concerns in particular a mounting arrangement for axial fans of the type described. The term "cased axial fans" includes bifurcated axial fans and aerofoil fans, both of which can have substantial dimensions, especially in the axial direction.

Single and three phase axial fans of the type described and for the aforesaid purposes are well known. The fans are manufactured to a universally used basic design to fit into a circular casing. In cased axial fans, the casing is formed with circular mounting flanges at opposite ends (in the axial direction). In plate mounted fans the casing is integrally formed at one end (in the axial direction) with a generally square mounting plate. Cased axial fans, especially, can vary in diameter from 25 cm up to 1.5 metres, with axial thicknesses ranging from 10 cm up to 1.2 metres. Thus, although constant endeavours are being made to make the fans slimmer and lighter in weight, nevertheless many cased axial fans are very heavy and difficult to handle.

The axial fans as aforesaid are frequently installed in ductwork and mounted in position between flanges which terminate the ductwork at the gap where the fan is to be located. It is to enable such mounting that the fan casing, within which the fan is mounted, is either provided with axially spaced flanges for fixing to the ductwork flanges (cased axial type) or is formed integrally with the end mounting plate for fixing between the ductwork flanges (plate mounted type). Fans of the plate mounted type are also sometimes mounted to a wall, ceiling or roof, at an interruption in the ductwork or at the end of the ductwork.

In all usage, but especially in the catering industry, servicing and cleaning of the fans is necessary relatively frequently. In catering establishments especially, where the fan extracts grease laden air and heat from commercial kitchens, grease accumulates on the fan blades, so that the fan works less efficiently, and grease also builds up in the adjacent ductwork. This leads to an environment in which Salmonella-type bacteria can breed, and also in which there is risk of a flash over fire leading to fan-assisted ductwork fires. Typically, therefore, cleaning is necessary at not more than four to six month intervals in catering establishments.

Currently, however, servicing is a difficult and time consuming task, because of the awkwardness of the numerous fittings which mount the fan in position in the ductwork, and the bulky and heavy nature of the fan when these fittings are released. The electrical connections, currently in the form of conventional wiring fixing to the fan motor terminals, are also awkward and time consuming to disconnect and re-assemble.

Because servicing is for the aforesaid reasons difficult and time consuming, and therefore expensive, axial fans of the type described and used for extraction purposes rarely receive adequate servicing and maintenance, and potentially dangerous conditions are allowed to develop, especially in the catering establishments.

It is an object of the present invention to provide a solution to the aforesaid problems.

According to the invention, there is provided an axial fan of the type described, in combination with a mounting means which is partially releasable to enable at least a part of the fan casing to be displaced out of its operative position in line with ductwork into an accessible position, whilst leaving said fan casing supported by the ductwork.

By virtue of the combination according to the invention, access is available to the casing interior and fan for maintenance and cleaning purposes, and also to the interior of the adjacent ductwork, without having completely to disconnect, handle and support the heavy fan casing carrying the fan. However, the mounting means is preferably fully releasable if complete detachment of the fan casing and fan is necessary.

Preferably, the fan motor is connected to a quick-release electrical coupling, such as a plug and socket, one part of which may be fixed to the exterior of the fan casing. Electrical disconnection of the fan can thus readily be effected, before the fan casing mounting means is partially or wholly released.

In the instance of a cased axial fan, the mounting means may conveniently comprise quick release bolts, such as bolts secured by wing nuts. These bolts may extend the full axial length of the fan casing, each bolt simul¬ taneously securing together the ductwork flange and casing end flange pairs at both axial ends of the- casing. Between the two flange pairs, the bolts may be surrounded by respective spacing sleeves, thereby to prevent distortion of the flanges when the bolts are tightened. Alternatively, shorter bolts may be employed, one set of such bolts for each axial end of the fan casing.

With the arrangement using quick release securing bolts, or similar releasably secured devices, and after electrically disconnecting the fan motor, all the bolts but one can be released, and the remaining bolt slackened, thereby to enable the fan casing to be swung out from the ductwork by a pivotal movement about said remaining bolt.

In the instance of a plate mounted fan, the mounting means preferably comprises a generally square frame for fixed mounting in the ductwork and relative to which the mounting plate of the fan is slidable out of the ductwork. The frame may have grooves in which two opposite edges of the fan mounting plate are slidable. In one arrangement, the square frame comprises a box open on one face (and on opposite faces aligning with the ductwork) to enable withdrawal of the fan from the ductwork and closed on its opposite face, and a securing means comprises a closure plate carried by the fan casing or by the box for closing said open face of the box.

Conveniently, the outer face of each end flange of the casing (in the instance of a cased axial fan), or at least the outer face of the plate (in the instance of a plate mounted fan), may be provided with a resilient layer, for example of rubber, to absorb vibration when the fan is operative and also to form an airtight seal between the casing and duct flanges or the mounting plate and duct flanges, and thus between the sections of ductwork in which the fan is interposed.

The quick release electrical coupling may conveniently consist of a socket fixed or mounted to the exterior of the fan casing, and a plug which cooperates with said socket. The coupling, which could instead be constituted by a junction box for example, is preferably made of a heat resistant and impact resistant material, typically mainly of a plastics material. In the case of a plug together two part coupling, a releasable securing means may be provided to ensure that the two coupling parts do not work loose during operation of the fan. An on/off switch may be incorporated in the coupling, and also a safety fuse. The coupling and its associated wiring can readily be made to suit 110, 240 or 415 mains supply voltages.

The invention will now be exemplified in the following description, making reference to the accompanying drawings, in which:-

Figure 1 shows an axial cased fan secured in position between two flanges terminating the ductwork in which the fan is to be operative;

Figure 2 again shows the fan casing mounted in the ductwork, and also shows an electrical socket and plug through which the fan is provided with power;

Figure 3 shows the fan casing swung out of the ductwork;

Figure 4 shows a modification of the arrangement of Figures 1 to 3 with the fan casing secured in place in the ductwork;

Figure 5 shows a first modification, with the fan casing withdrawn from the ductwork;

Figures 6 and 7 show a second modification in similar manner;

Figure 8 shows the modification of Figures 6 and 7 when seen looking along the line of the ductwork, with the fan casing in the withdrawn condition;

Figure 9 shows application of the invention to a plate mounted fan; and

Figure 10 shows application of the invention to a different construction of plate mounted fan.

The invention is applicable to axial fans of the axial cased type and of the plate mounted type. Figures 1 to 3 exemplify the invention applied to an axial cased fan.

Referring to Figures 1 to 3, the fan casing, within which the fan is mounted, comprises a circular fan casing 10 with a rubber cushion layer 11 on the outer faces of both its axial end flanges. This fan casing 10 is secured in position between two similar flanged members 22 which are fixed to the ends of the ductwork 12 by rivets, screws or other suitable fixings.

The fan casing 10 is secured in position by four or more steel bolts 13 (or like fixing devices) which extend the entire axial length of the fan casing 10 between the flanged members 22 and are secured by wing nuts 17 and sprung washers 16 (or by equivalent quick release fasteners). The fan casing 10 and fan are thus mounted securely in position for use. The shanks of the steel bolts 13 (or equivalent means) between the flanges of the fan casing are covered with sprung steel sleeves 15 which act as spacers.

The casing also carries fixed or mounted to it an electrical socket 18 for receiving an electrical supply plug 19 (Figure 2) which has a fixing bracket 20 with a relevant screw 21 or other suitable type of fixing (e.g. a push on snap connector) which holds the supply plug 19 in place and prevents loosening during operation of the fan.

In order to remove the fan and casing from the ductwork for cleaning and maintenance purposes, whilst still keeping it attached to the ductwork if necessary, first the electrical plug 19 is disconnected, as shown in Figure 2. All but one of the wing nuts 17 are then undone and removed, and the released bolts 13 are withdrawn. The remaining steel bolt 13 is slackened off enough to allow the fan casing 10 carrying the electrical socket 18 and rubber cushion flanges 11 to be swung out of the ductwork 12, the flanged members 22 of which remain in situ on the ends of the ductwork, as shown in Figure 3. This gives access to the fan and motor for cleaning and testing etc. If desired, the fan and motor can be removed from the casing, with the casing still attached to the ductwork. To replace the fan casing in the ductwork, the above described steps are carried out in reverse order.

The rubber cushion layers for absorption of vibration are not always necessary.

It will be appreciated that, if preferred or necessary, the fan casing can be completely removed from the ductwork by releasing the last wing nut and bolt 13.

The fixing in place of the fan casing 10 for fast release can be practised not only with the steel bolts 13 and wing nuts 17 described, but with any other suitable fixing devices which will permit displacement of the casing from the ductwork. The shape, size and manner of attachment of the electrical socket 18 and supply plug 19 is also subject to ready modification.

In the modification of Figure 4, all the long bolts of Figures 1 to 3 are replaced by short bolts 13 _f except for one long bolt which constitutes a hinging means 24. Reference 23 denotes the fan and motor carried by the casing 10. Withdrawal of the fan casing from the ductwork 12 is carried out in the manner described for the embodiment of Figures 1 to 3, except that two sets of short bolts 13 require to be released instead of the long bolts 13.

In the modification of Figure 5, similar reference numerals to Figure 4 are used for similar parts.

In this modification, the fan casing 10 carrying the fan and motor 23 is mounted between the flanged end members 22 of the ductwork 12 on a hinging means 24 defining a pivot axis about which the fan casing can be swung out of the ductwork. The fan casing carries a readily releasable electrical connector 25 through which in use power is supplied to the fan motor through a supply cable 29. The fan casing 10 normally secures in position in line with the ductwork 12 by means of a readily releasable latch in the form of a quick release clamping device, which is not shown in Figures 4 and 5 but can be a device similar to the device 26 shown in Figures 6 and 7 subsequently described, except that it is operative between the fan casing 10 and at least one of the flanged end members 22 of the ductwork, Alternatively, a simple securing bolt with a readily releasable wing nut may be employed on the side of the casing diametrically opposite to the hinging means 24.

Figures 6, 7 and 8 show another modification, using the same reference numerals as Figures 4 and 5 for similar parts. Reference 28 denotes support rods which locate the fan and motor 23 within the fan casing.

In this modification, the fan casing is split, approximately in a diametrical plane, into two parts 27, 27 one part 27 fixed between the flanged end members 22 of the ductwork 12 and the other part 27 hinged to the fixed part 27 at a hinging device 24. The support rods 28 locate the fan and motor 23 in the hinged part 27 of the casing, so that when a quick release clamping device 26 is released, the hinged part of the casing carrying the fan and motor can be withdrawn from the ductwork 12. Reference 25 again denotes an electrical connector, whereby the supply cable 29 can be readily released to facilitate withdrawal from the ductwork 12 of the hinged part 27 of the casing.

Figure 9 shows application of the invention to a plate mounted fan. The plate mounted fan 30 in question is shown in Figures 9(a) and 9(b) in side view and in front view.

In accordance with the invention, the fan 30 is normally housed, as shown in Figure 9(c), within a generally right rectangular box 34 having an open side face closable by a closure plate 31 fitted with magnetic or other catches 32. When the closure plate 31 is opened, the fan 30 is withdrawable from the box 31, to an accessible position shown in Figure 9(d).

In use, as indicated in Figure 10(a) subsequently described, the box 31 is fixedly mounted in the ductwork between two flanged end members which define an interruption in the ductwork.

When the fan 30 is to be cleaned and/or serviced, the closure plate 31 is opened to withdraw the fan in the manner above described. This also gives access behind the withdrawn fan 30 to the interior of the box, which can also be cleaned. Sliding movement of the fan 30 in and out of the box is facilitated by internal guides 33 at the bottom and top of the box 34 and with which the bottom and top edges of the mounting plate of the fan casing cooperate. The extent of withdrawal of the fan 30 may be limited by a releasable catch (not shown) .

As in preceding figures, reference numeral 25 indicates a quick release electrical coupling for a power supply cable 29. In the construction of Figure 9, this coupling is automatically broken when the fan 30 is withdrawn from the box 34 and is automatically re-established when the fan is fully pushed home on insertion into the box. Reference numeral 23 again indicates the fan impeller and motor, which is supported on the front plate of the fan casing by supporting rods 28.

Figure 10 shows the arrangement of Figure 9 applied to a different construction of plate mounted fan 30 , in which the front plate of the fan is provided with top and bottom flanges. Figure 10(a) shows the box 34 mounted in the ductwork 12, and Figure 10(b) shows the fan 30 withdrawn from the box 34, the ductwork being omitted in Figure 10(b) for reasons of simplicity and clarity. Other parts of the arrangement of Figure 10 will be clear by the use of reference numerals similar to those of Figure 9 for similar parts.

The arrangements of Figures 9 and 10, especially, can be employed at the end of a length of ductwork, for example at a wall, ceiling or roof. In this case the box 34 is fixed to the supporting structure (wall, roof etc.) in alignment with the end of the ductwork. Cleaning and servicing of the fan 30 is made relatively simple and easy compared with the known practice of mounting the fan casing directly to the structure.

Various modifications of the above-described and illustrated embodiments are possible within the scope of the invention defined by the appended claims.

Claims

1. An axial fan of the type described, in combination with a mounting means which is partially releasable to enable at least a part of the fan casing to be displaced out of its operative position in line with ductwork into an accessible position, whilst leaving said fan casing supported by the ductwork.

2. An axial fan according to claim 1, in which a part of the fan casing is diεplaceable out of the ductwork, whilst the other part of the casing is left in position in line with the ductwork and the displaced part remains attached to said other part.

3. An axial fan according to claim 1, in which the complete fan casing is displaceable out of the ductwork whilst remaining attached to said ductwork.

4. An axial fan according to claim 3, of the cased axial type, in which the flanges of the fan casing are mounted to the ductwork by mounting bolts, readily releasable to enable the fan casing to be pivotally displaced out of the ductwork about an axis at the periphery of the fan parallel to the fan axis.

5. An axial fan according to claim 4, in which the pivot axis is also defined by a releasable bolt means, so that the fan can be fully separated from the ductwork if required.

6. An axial fan according to claim 2, of the cased axial type, in which the fan casing is split, having one part fixed to the ductwork and its other part carrying the fan displaceable out of the ductwork relative to the fixed casing part.

7. An axial fan according to claim 6, in which the fan casing is split in a diametrical plane through the fan axis, and said other part carrying the fan is pivotable out of the ductwork on a pivotal connection to said fixed casing part about a pivot axis parallel to the fan axis.

8. An axial fan as claimed in claim 6 or claim 7, in which said other casing part carrying the fan secures to the fixed casing part by a readily releasable clip.

9. An axial fan according to claim 2, of the plate mounted type, comprising a generally square frame for fixed mounting in the ductwork and relative to which the mounting plate of the fan is slidable out of the ductwork.

10. An axial fan according to claim 9, in which the frame has grooves in which two opposite edges of the fan mounting plate are slidable.

11. An axial fan according to claim 9 or claim 10, including a means for securing the fan in the frame.

12. An axial fan according to claim 11, in which the square frame comprises a box open on one face (and on opposite faces aligning with the ductwork) to enable withdrawal of the fan from the ductwork and closed on its opposite face, and a securing means comprises a closure plate carried by the fan casing or by the box for closing said open face of the box.

13. An axial fan according to any of claims 1 to 12, in which the fan motor is connected to a quick release electrical coupling, releasable to permit withdrawal of the fan from the ductwork.