AU628467B2

AU628467B2 - Manhole closure for insulated sheet metal duct walls

Info

Publication number: AU628467B2
Application number: AU48613/90A
Authority: AU
Inventors: Manfred Meinig
Original assignee: MEINIG METU SYSTEM
Current assignee: METU-SYSTEM MEINIG KG
Priority date: 1989-01-19
Filing date: 1990-01-19
Publication date: 1992-09-17
Anticipated expiration: 2010-01-19
Also published as: JPH0350441A; AU4861390A; ATE81394T1; CA2007990A1; EP0379189B1; DD291621A5; DE59000337D1; EP0379189A1; ES2035653T3; DE3901393C1

Abstract

A maintenance cover with a maintenance opening and a maintenance lid for an insulated sheet-metal duct wall has a sheet-metal ring (23) running around the opening at right angles to the duct wall, which is constructed as a profiled sheet-metal strip. The sheet-metal ring (23) has an essentially U-shaped cross-section, with a centre part (13), a first limb (27) and a second limb (15) between which the insulation (12) is enclosed. On the first limb (27) there is integrally formed a folded pocket (14) with which the sheet-metal ring (23) is inserted into the section of the duct wall. The maintenance lid has an inner lid (11) and an outer lid (10), which can be drawn firmly against one another and rest in each case with one clamping edge on the duct wall (16) or on the sheet-metal ring (23) respectively. <IMAGE>

Description

L8~67FormI10 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952.60 COMPLETE SPECiFICATION (OR IGINAL) Class I t. Class Application Number: Lodged.

C. qmplete Specification Lc'dged;: 9:996:Aocepted: Published: *F"rorltv Related Art 6ii~re of Applicant NI'U-SYST METNIG KG Address of Applicant 'Ceitinger Strasse 186, D-7201 Rietheim-Weiheim 2, Federal 'Pepublic of Germany Attual Inverstor N'4AjFRED

METNIC

Add~ress tor Service W NI RM TOR1YS u2~ood oad, 'Ha!'thorn, Victoria, Australia Complete Specif ication for the Invention entitled: MANHOLE CLOSURE FOR INSULATED SHEFE' WiAL, DUCT' WALLS The following statement is a full description of this invention, Including the best method of performing It known to Our Ref: mei 077 METU-SYSTEM Meinig KG Seitinger Strasse 186 7201 Rietheim-Weilheim 2 Manhole Closure for Insulated Sheet Metal Duct Walls 0 son The invention concerns a manhole closure for insulated sheet metal duct walls with a manhole opening and manhole cover in accordance with the preamble of claim 1.

Sheet metal ducts which are used in air conditioning and ventilation systems are often provided with an insulating layer for thermal insulation and/or soundproofing. This insulating layer which can, for example, consist of glass wool can be applied to the sheet metal wall either from the outside as outer insulation or from the inside as inner insulation. The top side of the insulation is usually protected by a lining, e.g. in the form of an aluminum foil.

o Sheet metal ducts of this type must also have manhole openiings for inspection, maintenance of duct components and cleaning purposes which are sealed with manhole doors, covers, lids or the like.

With a design disclosed in DE 02 25 276 01, the manhole cover consists of a long, oval outer cover having a clamping _iCi~ 2 rim around its periphery which is connected with an inner cover of the same shape and size via two screw bolts which can be tightened from the outside by screw studs.

If this type of a manhole cover is to be used for an insulated sheet metal duct wall, then, with an outer insulation, the inner edge of the insulating layer can be covered and enclosed by a metal ring which is fastened to the outer duct wall by screws or rivets and expands conically outward. To accomplish this, the insulation must S be cut out over the whole cover area, as a result of which the entire area including the manhole cover forms a cold *bridge. In another embodiment according to the above industrial design, a two-piece metal ring is provided which aligns with the manhole opening and covers the edge of the insulating layer facing the manhole opening. Outer cover and inner cover lie directly on the metal ring and/or duct wall. The disadvantage in this case is that, due to the thin duct wall, the metal ring must be fastened to the duct gee wall with numerous rivets or screws. Moreover, the frame in sheet metal ducts insulated on the inside must, in addition, be sealed with a packing material.

It is the object of the invention to improve a manhole closure having manhole opening and manhole cover for insulated sheet metal duct walls in such a way that the ee ori S assembly is facilitated and a low-cost manufacturing is possible. At the same time, the insulating effectiveness of the manhole closure is to be improved.

This object is solved with the characterizing features according to claim 1 in a conventional manhole closure. The profiled metal ring according to this suggestion can be cut to the required length for the cutout of the manhole opening i I I I is 3

S

S.

S

S.

S 9

S

0 5 5

S

S S and easily mounted with th.e folded pocket on the metal rim edge of the cutout. The metal ring has an essentially U-shaped cross-section with a central part, a first flank and a second flank between which the insulation of the duct wall is enclosed. In an outer insulation, the metal ring is inserted into the opening with the folded pocket provided on the first flank of the U-section in such a way that the second flank of the U-shaped section surrounds the insulation from the outside. The same metal ring can be used for inner insulations without any modifications. In this case, it is inserted with the folded pocket into the cutout in such a way that the second flank of the U-shaped section surrounds the insulation from the inside.

To seal the manhole opening, the inner cover has, in an advantageous embodiment, a sealing tape which rests on the metal ring on the outside of the clamping rim. In sheet metal duct walls insulated on the outside, the folded pocket of the metal ring is preferably measured in such a way that it is covered by the inner cover resting on it and that the sealing tape of the inner cover seals with the sheet metal wall of the duct.

In duct walls insulated on the inside, the sealing tape of the inner cover rests on the second flank of the metal ring from the inside of the duct. To improve the seal, a seal can, in addition, be provided in the folded pocket. To accomplish this, a permanent plastic packing material can e.g. be injected into the folded pocket.

Preferably, the metal ring has a smaller curvature than the cutout prior to being inserted into the manhole opening. As a result of this, the metal ring is securely fixed in the cutout after insertion due to its inherent tension.

r 4 In a further advantageous embodiment, the contact ;oint of the two opposite ends of the metal ring can be connected, for example, by a sheet metal strip which can be i.serted into slits of the metal band. Moreover, the contact point can be covered by a self-adhesive aluminum strip.

In another advantageous embodiment, for particularly high demands on the insulation and seal of the manhole opening, the inner cover can be in two parts, that is, consist of an even cover plate which rests on the sheet metal duct wall S• and/or the metal ring from the inside and of a profiled 4.

intermediate plate. The intermediate plate is shaped like a truncated cone and has a bulge in the area of the rim which extends around the opening and protrudes outward. The two parts of the inner cover can be connected with the cover plate by means of screws or rivets at the junction point between the casing of the truncated cone and the bulge. The cover plate is coated with a continuous insulation in direction toward the outside of the duct. The edge of the cover is, preferably, bent slightly outward. This helps to press the seal against the duct wall in an area outside of the metal ring inserted into the opening. Due to the insulation of the co-cr, which can e.g. consist of polyethylene foam, the heat-absorbing cover inside the duct e is thermally insulated against the rest of the manhole covers. The protruding edge of the intermediate plate of the inner cover ensures that the manhole cover is centred on the inserted metal ring. Its strong profiling gives the .'ntire inner cover stability and ensures that the forces exerted by tightening the outer covet cre also transmitted to the sealing rim. The smooth innar side of the cover with the chamfered rim is aerodynamically very advantageous for the flow inside the sheet metal duct.

r:

II.

c -J 81 4

L

5 The invention is explained in greater detail in the following with reference to examples of embodiments which are illustrated in the drawings, showing: *r

S

0S 0e

*SSS

.r

OSSS

S

SS S Figure 1 Figure 2 Figure 3 Figure 4 a partial section of a sheet metal duct wall, insulated on the outside, with manhole opening and inserted manhole cover, a partial section of a sheet metal duct wall, insulated on the inside, with manhole opening and inserted manhole cover, a partial section of a sheet metal duct wall, insulated on the outside, with manhole opening and inserted manhole cover in an alternative embodiment, a perspective view of the profiled metal ring which is partially inserted into the cutout of the manhole opening, a perspective view of the metal ring according to Figure 4 connected at the contact point with a sheet metal strip, a cross-section of the metal band, a cross-section of the metal band in an alternative embodiment, a perspective view of the contact point of the metal ring according to Figure 4 with pasted on aluminum strip, Figure 5 Figure 6 Figure 6a Figure 7 i~ II -IC 'Ilr- 1 -6and Figure 7a a section through the metal ring along the line A-A of Figure 7.

S

t 0 6 0e*0

O

0 0 6 *0*0 0 S A duct wall 16 which is provided with an outer insulation 12 has an oval manhole opening into which, according to Figure i, a manhole cover having an outer cover 10 and an inner cover 11 is inserted. On the edge of the cutout, insulation 12 is enclosed with a metal ring 23 which is made like a profiled metal band. Metal ring 23 has an essentially U-shaped cross-section with a central part 13, a first flank 27 and a second flank 15 between which the insulation 12 is enclosed. The end of the first flank of the U-shaped metal band is shaped like an S, whereby its end is formed by a U-shaped folded pocket 14. Metal ring 23 is slipped onto the edge of the cutout in the duct wall 16 with the folded pocket 14 in such a way that the edge of the cutout is surrounded by the folded pocket 14 from the inside and from the outside. Advantageously, the metal ring 23 has a somewhat smaller curvature than the cutout prior to being inserted. It is then securely fixed in the cutout after insertion due to its inherent tension. Moreover, it can, according to Figure 5, be secured by a sheet metal strip 51 at the contact point 52 between the two ends. For this reason, two slits 50 each are punched into the central part 13 of metal ring 23 at both ends. Sheet metal strip 51 is inserted into the resultant fishplates. Alternatively or additionally, contact point 52 of metal ring 23 can be pasted over with a self-adhesive aluminum strip 37 in accordance with Figure 7 or 7a.

Outer cover 10 and inner cover ii of the manhole cover have .A I 7the same shape and size according to Figure i. Both covers have a clamping rim 26, 28 on the outside which extends around its periphery. Clamping rim 28 of outer cover rests on the second flank 15 of the U-shaped profiled metal ring 23. Clamping rim 26 of inner cover 11 has a sealing tape 21 on its side facing the outer cover 10, which can, for example, be in the form of a self-adhesive foam strip.

The sealing tape 21 covers the folded pocket 14 of metal ring 23 and sits tightly on the duct wall 16 inside the sheet metal duct.

A curved section, extending diagonally outward and passing over into an inwardly sunk curved section, adjoins each of 0*oo the even clamping rims 28, 26 of outer cover 10 anO. inner cover 11. The middle section of outer cover 10 and inner O ~cover 11 is slightly offset outward and contains one screw bolt 18 each (only one bolt can be seen in Figure 1 due to the illustration in cross-section through the oval manhole cover). The bolt 18 made as a lock nut is fixed with its :o ~head 22 to the inner cover 11 and penetrates the outer cover 10 which can be tightened by screw stud The shaft of each bolt 18 is surrounded by a cylindrical coil spring 19 which spreads the outer cover 10 and inner cover 11 apart when they are not in a tightened state so as to facilitate insertion of the manhole cover into the manhole opening.

For the purposes of insertion, screw stud 20 is unscrewed up to stop 17 on the end of bolt 18, whereby inner cover 11 and outer cover 10 are spread apart by spring 19. The oval manhole cover can be placed into the manhole opening after turning vis-a-vis the longitudinal axis. Often a turn of 300 is already sufficient to accomplish this. After turning I I r

I

~PI

S. 56

S

9 Sr

S@

8 back and fitting the inner cover 11 into the oval cutout, the two screw studs 20 are tightened until outer cover rests with its clamping rim 28 on flank 15 of metal ring 23 on the outside and seal 21 on clamping rim 26 of the inner cover 11 seals with folded pocket 14 or duct wall 16.

As shown in Figure 2, the same metal ring 23 can also be used for enclosing the insulation in sheet metal ducts insulated on the inside. The only difference vis-a-vis Figure 1 is that metal ring 23 is inserted into the cutout with its folded pocket 14 in such a way that the second flank 15 of metal" ring 23 surrounds the inner insulation from the inside. The sealing tape 21 of inner cover 11 then lies d. lectly on this flank. Usually, this is sufficient to seal the manhole opening. With particularly high demands on the tightness, an additional seal 29 can be provided in folded pocket 14, in accordance with Figure 6a, perhaps in the form of a permanent plastic sealing material which is injected into the folded pocket.

Although an additional insulation is not usually required due to the relatively large space between outer cover 10 and inner cover 11, in order to avoid greater heat losses at the manhole cover, a manhole cover constructed according to Figure 3 can be used for particularly exacting requirements.

The inner cover 11' is constructed in two parts; it consists of a profiled intermediate plate 30, in whose central area the two screw bolts 18 are placed in the above described manner, and of a flat cover plate 34 which abuts against the inner wall of the sheet metal duct. The intermediate plate of inner cover 11 is shaped like a truncated cone and has, in the peripheral area, an outwardly protruding bulge 31 around the cutout of the manhole opening. The intermediate plate 30 is connected with the cover plate 34

S

S S @0e0.0

S

SS*

5 5 ol o

ICP~IIIIIIIIR

I

9 by rivets 32, plastic screws or the like at the junction point between the casing of the truncated cone and bulge 31.

A continuous insulating layer 33 made of an elastic material, e.g. of polyethylene foam, is anplied to the outside of cover plate 34. The rim of cover plate 34 is curved slightly outward which facilitates pressing the seal against duct wall 16 in the area outside of folded pocket 14.

*0 Possible cross-sectional shapes of the profiled metal ring S. 23 are shown in Figures 6 and 6a. The metal band has an essentially U-shaped cross-section with a central part 13, a first flank 27 and a second flank 15. A U-shaped folded pocket 14 is placed cn the first flank 27 in such a way that f e* its free flank points in the same direction as the second flank 15 of the U-shaped profile. According to Figure 6, the folded pocket 14 passes over into an opposite U-shaped curve, so that, as a whole, an S-shaped profiling results between central part 13 and first flank 27.

In an alternative embodiment according to Figure 6a, a second U-shaped folded pocket 24 of the same shape and size, which points in the same direction and passes directly over into the second flank 15 of the U-shaped profile, can be provided in addition to the U-shaped folded pocket 14 on the end of the first flank 27. In this embodiment, a seal 29 6 made of a permanent plast. v sealing material is, moreover, injected into folded pocket 14 on the first flank to improve the tightness. Similarly, this type of a seal could also be provided in the other embodiment of the metal ring 23 according to Figure 6.

The described arrangement could also be installed in existing sheet metal duct walls without any difficulty. To 10 accomplish this in a sheet metal duct wall insulated on the outside, the insulation is first of all cut to the desired size and the cutout is then made in the sheet metal duct wall. The metal band, which has a slightly larger bending radius prior to being inserted into the cutout, is then inserted into the cutout with its folded pocket 14 on the first flank 27 of the U-shaped profile. If desired, it can additionally be fixed at the contact point of the two ends by a sheet metal strip and sealed by means of a self-adhesive aluminum strip. One must simply take care when inserting the metal band to ensure that the insulation is neatly enclosed and not damaged. After inserting and fixing the metal band, the manhole opening can be closed with the manhole cover.

S

0 *500 es

S

0

S..

S

0 S 0 S

S.

0*

Claims

1. Manhole closure for insulated sheet metal duct walls, with manhole opening and manhole cover, with a metal ring extending around the opeing at right angles to the duct wall and having a U-shaped cross-section, with a central part. 3 4'st flank and a second flank between which the insulation is enclosed in the area of the opening, whereby the manhole cover has an inner cover and an outer cover which can be tightened together and whereby both covers have a clamping rim resting on the duct wall or on the metal ring and a seal is provided on at least one clamping rim, characterised in that the metal ring consists of a profiled metal band, whereby a folded pocket is molded to the first flank, with which the metal ring is slipped onto the opening in the duct wall in such a way that the folded pocket surrounds the metal edge of the opening from the inside and from the outside.

2, Closure according to claim 1, characterised in that the metal ring is folded in the shape of an S at its first flank, whereby the end of the S-shaped fold is formed by the folded pocket which points in the same direction as the second flank of the U-shaped profile.

3 Closure according to claim 1, characterised in that the second flank of the metal ring passes over into a U-shaped folded pocket of the same shape and size as the folded pocket on the first flank of the metal ring, whereby both folded pockets point in the same direction, *9

4. Closure according to any one of the preceding claims, characterised in that the seal is a sei'.ng tape provided on the outside of its clamping rim.

5. Closure according to claim 4, characterlsed in that the sealing tape of the inner cover covers the folded pocket of the miaai ring on the inside of the duct and fits tightly on the duct wall,

6, Closure according to claim 4, characterlsed In that the sealing tape of the Inner cover lies on the second flank of the metal ring from the inside of the duct. I. ~CR L j .4 12

7. Closure according to any one of the preceding claims, characterised in that a seal is provided in the folded pocket,

8. Closure according to any one of the preceding claims characterised in that the metal ring is held in the manhole opening by spring tension of the ring acting outwardly in the direction of the rim of the manhole opening.

9. Closure according to any one of the preceding claims, charactorised in that the we- eppesite=ead=e-f metal ring is discontinuous and the two opposite ends of the metal ring can be connected at their contact point.

Closure according to claim 9, characterised in that the two opposite ends of the metal ring can be connected at their contact point by a metal strip which can be inserted into slits on the central part of the metal ring.

11. Closure according to any one of the preceding claims, characterised in that the contact point of the two opposite ends of the metal ring can be covered by a self-adhesive S aluminum strip.

12. Closure accordiilg to any one of the preceding claims, characterised in that the manhole opening and manhole cover have an elongated oval shape.

13. Closure according to any one of the preceding claims, characterised in that, on the Inner cover, two outwardly pointing screw bolts are provided which penetrate the outer *cover and which can be tightened by means of nuts a3ainst the tension of coil springs provided between the outer cover and inner cover.

14. Closure according to claim 13, characterised in that the ew .eke are partially received in a depression of the outer cover, Closure according to any one of the preceding claims, characterised in that inner cover and outer cover have the same shape and size.

A* r I

16. Closurs according 'o any one of the preceding claims, characterised in that the inner cover consists of a profiled intermediate plate and of a flat cover plate connected with it which covers the manhole opening on the inside of the duct.

17. Closure according to claim 16, characterised in that the intermediate plate of the inner cover is shaped like a truncated cc ie and has an outwardly protruding bulge extending around the manhole opening in the peripheral area.

18. Closure according to claim 17, characte,:sed in that the intermediate plate of the inner cover is connected with the cover plate by means of screws or rivets at the junction point between the conical surface of the 1.uncated cone and the bulge,

19. Closure according to claim 16, 17 or 18, characterised in that an insulating layer is applied to the outside of the cover plate.

20. Closu re according tc any one of the claims 16 to 19, characterised in that the cover plate has a rim which is curved in direction of the duct wall.

21. Closure according to any one of the claims 16 to 20, characterised in that the rim of the cover plate covers the folded pocket of the metal ring and fits tightly on the duct S:wall.

22. Closure according to claim 1, substantially as herein described with reference to the accompanying drawings. DATED this 13th day of February 1992. i METU-SYSTEM MEINIG KG WATERMARK PATENT TRADEMARK ATTORNEYS THE ATRIUM 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRAUA RCS/CH (DOC.8) AU4861390.WPC