CA1185826A - Ventilating device for cable ducts - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

This ventilating device is particularly intended for cable ducts in petrochemical plants.
It has a flap (19), which automatically closes on exceeding a predetermined maximum temperature.
A closing device and a holding open device cooperating with a release mechanism are associated with flap (19) and are together arranged within a frame-like insert (13). Insert (13) can be fitted into a protective cover recess of a cable duct (4) having a size corresponding to the dimensions of the insert.

Description

EYE TUT DYES OR KIWI DTJC~S

the invention relates -to a ventilating device for cable route ducts, particularly in petrochemical plants, having at least one automatic closing flap. Most electrical cables are now insulated by a covering made from plastics materials, the latter being generally heat sensitive, easily flammable plastics. wherefore, a number of proposals have already been made for providing cable fireproofing.
thus, for example, it has already been proposed to apply a self-quenching fireproofing agent to the cable, e.g. of the type known from German Pa-tent

2 039 9~6. However, this process is relatively complicated and costly and also cannot be used in lo all. cafes, e.g. it cannot be used if it is a question of protecting function lye important control cables of a large petrochemical plant in such a way that in all circumstances Thurman operable for more than 30 minutes, because they are used for cont~lling all the emergency functions and measures, such as e.g. the closing of valves.
Hereford cable coverings with a protective sheath constructed in duct-like manner have been developed, itch are either made from double-walled sheet metal or from mineral fire cement putts, a plurality of ventilating flaps being provided for the ventilation of the interior of -the duct. these verltilatil.~g flaps arc held in the open position bin heat-sensitive blocking members, which melt under the action of a large amount of heat, so -that the flaps close under the action of their ohm weight. However, it is only in rare circumstances that such a ventilating device fulfill its set function. hi is not only due to the fact that the closing force I

of the ventilating flaps is extremely small, but also because the flaps are only fitted to the top of the duct and not to its sides to enable them to flap shut under the action of their own weight.
This leads to an inadequate ventilation of the duct interior, with the additional disadvantage that objects falling on to the duct can lead to a jamming of the ventilating flaps.
The problem of -the invention is to provide a ventilating device, which has a simple construction and ensures a completely satisfactory ventilation of the interior of the duct. In addition, it ensures that the inside of the duct remails protected from the heat action over a long period in the case of a fire, so that cables located therein rem if. operable during this time even if a fire occur.
According to the invention this problem is solved by a ventilating device of the aforementioned type in which a closing device and a holding-open device cooperating with a release mechanism are associated with the flap. A ventilating device constructed in this way need not necessarily be mounted on the top of the duct, where dropping objects con lead to the jamming of the flap. Due to the positive closing force of its closing device, a ventilating device constructed in this way can be mounted on any random point the duct wall, e.g.
on the side walls or on the bottom, so that dropping objects are deflected and cannot cause jamming. the closing force of the closing device is five times and preferably ten times the Lotte of the flap.
the release mechanism and/or the holding-open device can form a smoke gas-sensitive control element, ~æ~

which leads to -the advantage that the flap closes when these is an unusual amount of smoke, and not only on exceeding a prede~errnined temperature.
According to a preferred embodiment of the ventilating device according to the invention the closing device, holding-open device and release mechanism are arranged in the interior of a ~rame-like insert, on to which is articulated : the flap and which can be fitted into a recess of I the protective sheath of a cable duct which has corresponding external dimensions. the advantage of such a ventilating device is that it forms a compact unit which cay even be rap_dlJ- and effortlessly fitted in the case of existing plants and which can equally vapidly and effortlessly be replaced.
he closing device of the ventilating device according to the invention has preferably at least one closing string for producing the flap closing ours. this dosing spring is preferably constructed as a torsion spring. However, the flap closing force can also be applied by means of one or more tension springs.
one holding-open device of the ventilating device according to the invention can have a spring-lulled, bendable pussier for winch -the release nn3chani~3m can have an operating member which keeps it straight and/or bends it, the forces of the operating member preferably being directed substantially perpendicularly on to the spacer According -to a preferred embodiment of -the ventilating device according to the invention the operating member comprises a heat-sensitive filament and at least one spring.
.

Lo The ho]ding-open device of the ventilating device according to the invention preferably has a spring-loaded toggle lever itch, in the worming position, is advantageously exposed to a force holding it in the vicinity of its dead center and on operating the release mechanism a force josh bends it and which can be applied by the closing force of the aforementioned closing spring.
The force holding the toggle lever in the working position is preferably applied by a spring, acting in the vicinity of the toggle lever joint and pressing the toggle lever against a stop member, arranged in such a way that the toggle lever strikes against it before reaching its dead center position.
the force or force component bending the toggle lever is staller than the closing force of the closing device, acts in the pivot plane of the toggle lever and can be applied by a separate spring, which can be coaxial to the spring holding the toggle lever in its working position.
According to a preferred embodiment of the v~!ltilatirlg device according to the invention the' 'holding-open device has a collapsible tension spring lr/hicln is press reloaded in the working petunia.
'issue tension spring is preferably a soft spring, whose coils are closely juxtaposed and whose diarnet~r is small cornered with its length.
'he release mechanism preferably has at least one heat-sensitive part responding to a predetermined external position and which in the working position is preferably under a tensile stress. 'this part preferably comprises a synthetic material filament or thread, which breaks on reaching a predetermined external temperature.

the opening angle of the ventilating flap can be up to 90 and it preferably 50.
Filthier details, features and advantages of the invention can be gathered from the claims and description of preferred embodiments in conjunction with the diagrammatic drawings, wherein show:
jig. 1 a-perspective view of a cable duct with a ventilating device according -to the invention.
Fig, 2 a sectional representation of a fitted ventilating device according to the invention.
jig. 3 a perspective view of an embodiment of a ventilating device according to the invention, partly in section.
15 Fig. 4 a perspective view of an embodiment of the closing device of the ventilating device according to the invention.
Fig. 5 the closing device of Fig. 4 and the means cooperating therewith.
20 Fig. 6 a perspective view ox' another embodiment of a ventilating device according to the invention, partly in section.
Fig 7 various embodiments of the closing device.
Fig. 8 a perspective view of a cable duct with ventilating devices according to the invention.
Fig. 9 the supporting structure of the cable duct of Fig. 8.
jig. 10 various fastening or fixing elements to be used in connection with the assembly of the cable duct of Fig. 8.
Fig. 11 a first assembly stage of the supporting - structure of Fig. 9, Fig. 12 a further assembly stage of the supporting structure of Fig 9.

Fig. 13 the fixing of the cover plates to the supporting structure.
Tune cable route duct shown in Fig. 1 is used for the protection of a cable route in winch a cable trough 1 is provided for a plurality of juxtaposed cables and which is secured to supports 3 fixed -to ,-, a wall I the cable duct essentially comprises a protective sheath fixed -to vertically directed frames 5, which are in turn fixed to the cable trough 1, preferably by means of screws 6 via intermediate pieces 7.
Protective sheath 4 has a rectangular cross-section. Its walls comprise approximately 50 mm thick flat plates, which are joined together and specifically comprise a base plate 8, a top plate 9 and two side plates 10, 11.
In the represented embodiment plates 8 to 11 are in each case constructed in a plurality of parts, i.e. they comprise a plurality of individual rectangular plates, whose narrow sides abut against one another.
On side plates 10, 11 are provided ventilating devices 12 and specifically preferably at different ! heights, so that -they ensure a good air circulation in the interior of the duct.
In the represented embodiments, the individual parts of the ventilating device 12 are in each case arranged in or on a frame-like insert 13, which comprises four joined, flat, heat-resistant plates 14 -to 17 having a thickness of about 12 mm and fixed, preferably by adhesion, into a recess of the cable duct, the size of the recess corresponding to the external dimensions thereof.

flap I is articulated by means of one or more hinges 18 on the side remote from the interior of the duct to the upper plate 15 of frame 13. the hinge issue is substantially horizontal. Flap 19 has a shopped cross-section, so -Tut in its closed position it partly projects into the interior of frame 13 and ensures a good air seal. In the embodiment of Figs. 2, 5 and 6, flap 19 comprises two mineral fire plates or boards, ' 10 in each case having a thickness of about 12 mm.
however, in the embodiment of Fig. 3, flap 19 is made from a solid mineral fire board with a thickness of about 24 mm.
In each case a closing device and a holding-open device cooperating with a rules mechanism are associated with flap 19. the closing device has at least one closing spring in all embodiments.
he closing device in the embodiment of ~ig7 3 comprises two tension springs 20, fixed by in each case one end to the loller plate I of frame 13 and by the other end -to flap 19. The closing device of the embodiment of Figs. 4 and 5 comprises a torsion spring 21, which is molted in a casing 22 fixed to the upper plate 15 of frame lo. the free ends 23, 24 of torsion spring 21 are displaceable mounted in a guide rail 25 fixed to the inside of flap 19.
it. pa shows the preferred configuration of the tension springs 20. In place of the two -tension springs 20, there need only be a single tension spring 26, whose tensile force is reversed by a clip 27 (cf. jig. 7b) or two cords 28, 29 of jig.
7c). - , so In each case the holding open device comprise a spring-loaded, bendable spacer.
In the embodiment ox Fig. 3 the spacer comprises a toggle lever formed by two linkages 30, 31 connected to one another in an articulated manner and whose ends remote from the toggle joint , 32 are articulated to the flap 19 or to a rod 33 held by frame 13. In the vicinity of toggle joint 32, a thread or filament 34 is fixed to one of the two linkages, said filament being made from a heat-sensitive material and being under the action of a tension spring 35 fixed to one side wall 16 of frame 13. By means of spring 35 9 toggle lever 30, 31 is drawn slightly beyond its dead center position against a rod 36 serving as a stop member and which is provided in the interior of frame 13.
Filament 34 and the spring 35 cooperating threaten in the present case forms the release mechanism cooperating Ruth the holding-open device formed by toggle lever 30, 31.
In the embodiment of Fig. 5, the spacer comprises a collapsible tension spring 37, which is pressure loaded in the working position and whose two ends are fixed in short pipe portions 38, 39, which are in turn fixed to casing 22 or to flap 19, particularly to guide rail 25. With -the tension spring 37 serving as the spacer is associated a rclca~e mechanism having a leaf spring 40 on which engages a spring-loaded or weight-loaded thread 41.
thread 41 it made from a heat-sensitive material and breaks on reaching a predetermined external temperature so that the lea spring 40 is forced against the tension spring 37 serving as the spacer.
this in -turn leads to the bending of tension spring 37 and flap 16 is forced into its closed position under the action of torsion spring 21.
In the embodiment of jig. 6 the spacer comprises two plastic shaped parts 42, 43, whereof one is fixed to the inside of flap 19 and the other is fixed to the bottom 14 of frame 13. The two ', shaped parts 42, 43 connect -thin filamentary retaining members 44, which initially ensure that I, flap 19 is held open, but on reaching a predetermined external temperature give way so that flap 19 can be closed by the associated closing spring, which is not shown in Fig. 6 so as not to overburden the drawing.
Fig. 8 shows a portion 54 of a cable covering 15 having a base plate 50, two side plates 51, 52 and a top plate 53 and which can be terminally connected to correspondingly constructed and dimensioned portions In order to bring about a terminal tight connection of adjacent portions 54, the individual portions have at one of their end faces an internal frame, which can be terminally inserted into the adjacent portion. this frame comprises individual trips 55-60, preferably made from the same material as plates 50 to 53 and stuck to one another and to plates 50 to 53 by means of a heat-resistant Adhesive. the facing end faces of strips 55 to 60 can have weather seals, as can the plates 50 to 53 of the individual cable covering portions 54.
Unlike in the embodiment of jig. I the supporting structure associated with the cover plates can advantageously comprise individual frames 60, 61 (cf. Fig. 9), which are interconnected by means of angle bars 62, which are provided with elongated slots 63. In the embodiment of jig. 9, frame 61 -comprises four flat bar irons 64, provided with elongated slots 65. Angle iron 62 and screws 66 are provided for the interconnection of the flat bar iron 64. Between the two vertically directed bar irons I there are U-shaped bearing rails 68, ' whose members point downwards and for which bends J 69 and screws 70 are provided for fixing them to the vertical bar irons 64 (Fig. 12). the bearing rails 68 are screwed to the bottom of the cable 10 trough by means of screws 71.
Unlike in the embodiment of jig. 1, cover plates 50 to 53 can be fixed to the supporting structure by means of fastening elements 72, 73 which can be screwed there-to and which are pressed 15 by their end faces into the said plates. Such hastening elements 72, 73 are shown in Figs boa and 10c. the fastening elements are made from stable sheet metal and have essentially a U or Z-shape, In each case they have a member provided 20 with an elongated slot 74 and by means of which they can be fixed to the supporting structure. whey are also provided in each case with a member having a tip 75. By means of such fastening elements it is possible to adopt the following procedure during 25 the assembly or fitting of the cover plates.
Initially a plurality of the U-shaped fastening elements 72 are screwed to the lower angle rails 63 of the supporting structure in such a way that the member provided with tip 75 is directed upwards.
30 When this has taken place, a side plate 51 or 52 ; can be placed from above on the tip of fastening element 72, the substantially Z-shaped fastening elements 73, whose tips are to be pressed into the end faces of the plates, can then be used for fixing -to frame 61 or the vertical rail 64 of frame 61.
this can be followed by the screwing of fastening element 73 to frame 61. In addition to the substantially U or shopped fastening elements 72~
73 through-fastening elements can be used for fixing to the plates and an embodiment thereof is shim in Fig. God. the fastening element 76 shim in Fig. God /! has a large, substantially disk-shaped head 77, to which is fixed a shank 78. At -the free end of shank 78 is provided a thread 79 on to which can be squired a nut 9 after shank 78 with its -thread 79 to the front being passed -through a cover plate and an elongated slot ox the supporting structure.
In the case of the supporting structure of Fig. 9, the individual frame 61 can, if necessary, be connected by parallel perforated rails 80 I
Fig. 13) in addition -to the four angle rails 62, these perforated rails help to stabilize the supporting structure and are preferably always used if the individual cover plates have to be assembled from plates juxtaposed in the longitudinal direction of the over.
In the construction of the supporting structure of Fig. 9, one starts with the bearing rail 78 to be fixed to the bottom of cable -trough 1 by screws 71 (cf. Fig. 11), Bends I are to be fixed to both ends of said beaning rails 68 by jeans of screws 70.
For stability reasons two bends 49 are -to be provided at each bearing rail end (of, jig. 12). If the supports 3 carrying the cable trough 1 are-sufficiently stable and so dimensioned that they project on either side of trough 1, the bends 69 can be directly fixed to supports 3, 50 that bearing rails 68 are no longer necessary One of the flat bar irons 64 is to be fixed by a screw 70 to free members of bend 69 (cf. Fig.
12). When this has taken place the upper and lower ends of the vertically aligned flat bar iron 64 are to be screwed in each case to an angle Roy 63. It is then possible to fix the horizontal j flat bar iron 64 to angle rails 62.
Without leaving the basic idea of the invention, the flap of the ventilating device can also be constructed as a sliding, hinged or swing door, which can be slid swung or pivoted by its closing device parallel to the duct wall via an opening therein. A ventilating device constructed in this way has the advantage that it has no parts projecting outwards from the duct wall and which could serve to hold back objects dropping on to the duct.

Claims (18)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A ventilating device for cable ducts, the ducts having a protective exterior wall of thermally-insulating material, the device comprising:
at least one flap of thermally-insulating material, mountable at an opening in said exterior wall, the flap being movably mounted and biased to close automatically on exceeding a maximum temperature and thereby seal the opening;
a closing device attached to the flap and biasing the flap to close; and, releasable holding means for normally holding the flap open, said releasable holding means including at least a heat sensitive means for releasing the flap from its open position when a maximum tempe-rature is exceeded.

2. The device of claim 1, wherein a smoke gas-sensitive control element cooperates with at least one of the release mechanism and the holding-open device, to close the flap in response to fire conditions.

3. The device of claims 1 or 2, further comprising a frame-like insert mountable in the opening in said exterior wall, the closing device, holding-open device and release mechanism being arranged within the frame-like insert, to which the flap is articulated and which is adapted to fit into a recess of the protective exterior wall of the cable duct of corresponding external dimensions.

4. The device of claim 1, wherein the closing device has at least one closing spring for producing a closing force.

5. m e device of claim 4, wherein the closing spring is constructed as a torsion spring.

6. The device of claim 4, wherein the closing spring is constructed as a tension spring.

7. The device of claim 1, wherein the holding-open device has a spring-loaded, bendable spacer.

8. The device of claim 7, wherein the release mechanism has an operating member, which in a normal mode keeps the spacer extended and in response to fire conditions bends the same.

9. The device of claim 8, wherein forces exerted by the operating member are directed substantially perpendicularly onto the spacer.

10. The device of claims 8 or 9, wherein the operating member has at least one heat-sensitive thread and at least one spring operating the release mechanism.

11. me device of claim 1, wherein the holding-open device is a spring-loaded toggle lever.

12. me device of claim 11, wherein the toggle lever is exposed to a force holding it in the vicinity of its dead center while holding open the flap, and upon operating the release mechanism the toggle lever is exposed to a force which bends it.

13. m e device of claim 12, wherein the force is exerted by the closing spring.

14. m e device of claim 12, wherein the force is transverse to the toggle lever.

15. The device of claim 1, wherein the holding-open device has a bendable tension spring, which is pres-sure-loaded in the working position.

16. The device of claim 1, wherein the release mechanism has at least one heat-sensitive part responding to a predetermined external temperature.

17. The device of claim 16, wherein the heat-sensitive part is a synthetic material thread, which is under tensile stress in the working position and breaks on reaching a predetermined external temperature.

18. me device of claim 5, further comprising a guide rail fixed to an inner surface of the flap, and the torsion spring having free ends displaceably mounted in the guide rail.