Title:
Plastic duct terminator
Kind Code:
A1


Abstract:
A duct terminator and supplemental components of a terminator system are described. The duct terminator includes a tubular body having a distal end and a proximal end, the proximal end being adapted to receive a conduit. A removable diaphragm is adjacent the distal end. The terminator can include an inner mounting ring and an outer mounting ring at the distal end. A single circumferential collar extends around the outside of the tubular body. The supplemental system components include a terminator seal, an extender and a bell, each of which have a proximal end adapted to engage the distal end of the duct terminator. The extender has a distal end shaped to replicate the distal end of the duct terminator.



Inventors:
Sack, James A. (Elverson, PA, US)
Application Number:
10/754855
Publication Date:
08/12/2004
Filing Date:
01/09/2004
Assignee:
SACK JAMES A.
Primary Class:
International Classes:
E03F5/02; (IPC1-7): E04B1/82
View Patent Images:



Primary Examiner:
BUCKLE JR, JAMES J
Attorney, Agent or Firm:
John J. Marshall (Berwyn, PA, US)
Claims:

What is claimed is:



1. A duct terminator comprising: a tubular body having a proximal end and a distal end; a removable diaphragm adjacent the distal end; the tubular body comprising a proximal section having a first average internal diameter and a distal section having a second average internal diameter, the proximal and distal sections being separated by a step; a circumferential collar extending around the outside of the proximal section; longitudinal proximal ribs extending from the circumferential collar toward the proximal end; and longitudinal distal ribs extending from the circumferential collar toward the distal end.

2. The duct terminator of claim 1 wherein the internal diameters of the proximal and distal sections are tapered less than about 0.40 degrees.

3. The duct terminator of claim 1 further comprising an inner mounting ring and an outer mounting ring on the distal end.

4. The duct terminator of claim 3 wherein the removable diaphragm includes a peripheral ring and the removable diaphragm can be removed from the tubular body at an area of weakness between the peripheral ring and the outer mounting ring.

5. The duct terminator of claim 1 wherein the circumferential collar includes a portion that extends substantially concentrically with the longitudinal axis of the tubular body.

6. The duct terminator of claim 1 wherein the longitudinal distal ribs and the longitudinal proximal ribs are circumferentially offset from one another.

7. A duct terminator comprising: an injection molded tubular body having a proximal end and a distal end; a removable diaphragm adjacent the distal end; and a circumferential collar reinforced by distal longitudinal ribs extending from the collar toward the distal end; the tubular body having an inside surface that is tapered less than 0.40 degrees.

8. The duct terminator of claim 7 further comprising an inner mounting ring and an outer mounting ring on the distal end.

9. The duct terminator of claim 8 wherein the removable diaphragm includes a peripheral ring and the removable diaphragm can be removed from the tubular body at an area of weakness between the peripheral ring and the outer mounting ring.

10. The duct terminator of claim 7 further comprising proximal longitudinal ribs extending from the circumferential collar toward the proximal end;

11. The duct terminator of claim 10 wherein the proximal longitudinal ribs are circumferentially offset from the distal longitudinal ribs.

12. The duct terminator of claim 7 wherein the circumferential collar includes a portion that extends substantially concentrically with the longitudinal axis of the tubular body.

13. A duct terminator comprising: a tubular body having a distal end and a proximal end, the proximal end being adapted to receive a conduit; a removable diaphragm adjacent the distal end, the removable diaphragm comprising a peripheral ring; an inner mounting ring and an outer mounting ring at the distal end, the inner mounting ring disposed on the removable diaphragm; the diaphragm being removable at an area of weakness between the peripheral ring and the outer mounting ring; and a circumferential collar extending around the outside of the tubular body.

14. The duct terminator of claim 13 wherein the tubular body comprises an internal diameter with a taper of less than 0.40 degrees.

15. The duct terminator of claim 13 wherein the tubular body comprises a proximal section having a first average internal diameter and a distal section having a second average internal diameter, the proximal section and distal section being separated by a step.

16. The duct terminator of claim 15 wherein the proximal section and distal section each have a taper of less than 0.40 degrees.

17. The duct terminator of claim 13 further comprising distal longitudinal ribs extending from the circumferential collar toward the distal end and proximal longitudinal ribs extending from the circumferential collar toward the proximal end.

18. The duct terminator of claim 17 wherein the distal longitudinal ribs and proximal longitudinal ribs are circumferentially offset.

19. The duct terminator of claim 13 wherein the circumferential collar includes a portion that extends substantially concentrically with the longitudinal axis of the tubular body.

20. A duct terminator system comprising: a duct terminator comprising: a tubular body having a distal end and a proximal end, the proximal end being adapted to receive a conduit, a removable diaphragm adjacent the distal end, an inner mounting ring and an outer mounting ring at the distal end, the inner mounting ring disposed on the removable diaphragm, and a circumferential collar extending around the outside of the tubular body; and at least one supplemental system component comprising a proximal end adapted to engage one or both of the mounting rings of the duct terminator, the supplemental system component being selected from the group consisting of a terminator seal, an extender and a bell.

21. The duct terminator system of claim 20 wherein the supplemental system component is an extender having a distal end shaped to replicate the distal end of the duct terminator.

22. The duct terminator system of claim 21 wherein the extender includes a removable diaphragm adjacent the distal end, and an inner and outer mounting ring at the distal end.

23. The duct terminator system of claim 22 wherein the removable diaphragms of the extender and the duct terminator each include a peripheral ring and each can be removed at an area of weakness between the peripheral ring and the outer mounting ring.

24. The duct terminator system of claim 21 further comprising a terminator seal, wherein the proximal end of the extender can be engaged with the distal end of the duct terminator, and the seal can be engaged with the distal end of the extender.

25. The duct terminator system of claim 21 further comprising a bell, wherein the proximal end of the extender can be engaged with the distal end of the duct terminator, and the bell can be engaged with the distal end of the extender.

26. The duct terminator system of claim 20 wherein the supplemental system component is a seal, the seal being reusable.

27. A duct terminator system comprising: a duct terminator comprising a tubular body having a proximal end and a distal end, and a universal mounting structure on the distal end; at least two different supplemental system components each having a connecting structure on a proximal end adapted to connect with the universal mounting structure, the supplemental system components being selected from the group consisting of a seal, an extender and a bell.

28. The duct terminator system of claim 27 wherein one of the supplemental system components is a reusable seal.

29. The duct terminator system of claim 28 wherein the connecting structure of the reusable seal fits inside of the universal mounting structure such that the seal does not become locked in concrete when concrete is poured around a combined terminator and seal.

30. The duct terminator system of claim 27 wherein one of the supplemental system components is an extender.

31. The duct terminator system of claim 30 wherein the extender has a distal end that replicates the universal mounting structure.

32. The duct terminator system of claim 27 wherein one of the supplemental system components is a bell.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority from U. S. Provisional Application No. 60/439,008, filed Jan. 9, 2003, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The invention relates to duct terminators used to provide knock-outs in ducting for into concrete structures.

BACKGROUND OF THE INVENTION

[0003] Concrete structures such as underground sewer, water and/or electrical junctions, pump or transformer enclosures, culverts, and similar vaults are often “precast’ in standard configurations. The structures are provided with cylindrical ducts through the walls to pass electrical cables for electrical power, telecommunications, or other conduits into the vault. Some of the ducts may not be used. Consequently, it is common to originally terminate (close) the ducts with a plastic diaphragm in each duct to provide a waterproof seal. The diaphragm is a knock-out part that can be removed if the duct will be used.

[0004] A conventional duct terminator is usually an injection molded plastic part that is used as an insert in the concrete mold to define the duct. It is typically a hollow cylindrical tube with a diaphragm inside its barrel that seals the barrel and prevents water from entering the vault if the duct is not used. The diaphragm includes a “knock-out” line that is weaker than the surrounding portions such that the diaphragm can be pushed out of the terminator barrel to open the duct.

[0005] A conventional duct terminator has multiple ribs running about the circumference of the part to anchor the terminator in the concrete wall. To form the ribs, conventional terminators are molded in an injection system that requires a two action molding tool.

[0006] The configuration of the conventional terminator also requires the molder to eject the part from the tool by pushing it off from the far end “knock-out”. Thus, the thickness of the rim on the knock-out may be determined in part by the need to withstand the mold ejection rods without punching out the diaphragm. A thick rim withstands the action of the push rods, making it easier to push the part off the tool. On the other hand, a thin rim makes it easier to punch the diaphragm out while in a concrete wall, without leaving any plastic chards on the rim.

[0007] As the injection molded part is pushed off the mold tool from the far end, it tends to constrict, resisting its removal from the mold. In order to minimize the effect of constriction, a conventional terminator has a relatively large degree of taper, at least about 0.5 degrees, and more commonly up to about 2 degrees, to its internal diameter (“I.D.”). A part with less taper would allow for better adhesion between the pipe, which has no taper, and the part when in use.

SUMMARY OF THE INVENTION

[0008] The invention relates to a duct terminator and to a terminator system comprising a duct terminator with supplemental components. The duct terminator includes a tubular body having a distal end and a proximal end, the proximal end being adapted to receive a conduit. A removable diaphragm is adjacent the distal end. The terminator includes a universal mounting structure, such as an inner mounting ring and an outer mounting ring at the distal end, for receiving a supplemental component. A single circumferential collar extends around the outside of the tubular body closer to the proximal end than the distal end.

[0009] The duct terminator can be injection molded with an internal diameter having a taper of less than 0.40 degrees. The taper can be so small because the molded part can be ejected from the mold tool at reinforced ejection points on the circumferential collar near the proximal end.

[0010] The supplemental system components include a terminator seal, an extender and a bell, each of which have a proximal end adapted to engage the universal mounting structure on the distal end of the duct terminator. The extender has a distal end shaped to replicate the universal mounting structure of the duct terminator. The supplemental components can be used in combination with the duct terminator to allow a concrete vault builder to create points of entry for conduits in walls of various thicknesses using only a few stock components.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] For the purpose of illustrating the invention, there are shown in the drawings forms which are presently preferred; it being understood, that this invention is not limited to the precise arrangements and instrumentalities shown.

[0012] FIG. 1 is a perspective view of the side and distal end of a duct terminator according to an embodiment of the present invention.

[0013] FIG. 2 is a perspective view showing the proximal end of the duct terminator of FIG. 1.

[0014] FIG. 3 is a perspective view of a terminator seal according to an embodiment of the present invention.

[0015] FIG. 4 is a perspective view of the seal of FIG. 3 engaged with the distal end of the duct terminator of FIG. 1.

[0016] FIG. 5 is a cross-sectional view taken through line 5-5 in FIG. 4.

[0017] FIG. 6 is a perspective view of an extender according to an embodiment of the present invention.

[0018] FIG. 7 is a perspective view of a bell according to an embodiment of the present invention.

[0019] FIG. 8 is a cross-sectional view of an assembly of the duct terminator of FIG. 1, the extender of FIG. 6 and the bell of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0020] In the Figures, in which like numerals indicate like elements, there is shown a duct terminator and terminator system according to an embodiment of the present invention. As shown in FIGS. 1 and 2, the system includes a duct terminator 10 having a tubular body 12. The duct terminator 10 can be attached to a form used for pouring a concrete structure, such as a wall of an underground vault. The duct terminator's tubular body 12 defines an opening in the poured concrete wall that can be used for receiving conduit, such as a pipe carrying power, telecom or other wires, cables or the like, into the structure.

[0021] The tubular body 12 has a distal end 14 and a proximal end 16. As used herein, the terms “proximal” and “distal” refer to the intended position of the ends 14, 16 (or other component) relative to an incoming conduit. Thus, a conduit coming into the structure would be inserted into the proximal end 16 of the duct terminator 10.

[0022] The duct terminator 10 includes a single circumferential collar 18. The circumferential collar 18 includes a portion 20 that projects radially from the tubular body 12 and a portion 22 that extends from the top of the radially projecting portion 20 substantially concentrically with the longitudinal axis of the tubular body 12. The radially projecting portion 20 and concentrically extending portion 22 together provide the conferential collar 18 with an L-shape when viewed in cross-section.

[0023] The duct terminator 10 includes distal longitudinal ribs 24 on the distal side of the circumferential collar 18 and proximal longitudinal ribs 26 on the proximal side of the circumferential rib 18. The distal longitudinal ribs 24 extend from the circumferential collar 18 toward the distal end 14 of the duct terminator. The distal longitudinal ribs 24 are preferably spaced apart about thirty (30) degrees from one another. A series of proximal longitudinal ribs 26, which extend from the collar 18 toward the proximal end 16, are also preferably spaced apart about thirty degrees from one another. Although the distal ribs 24 and proximal ribs 26 can be made in line with one another, it is preferred that they be circumferentially offset by about 15 degrees as shown in the drawings.

[0024] The duct terminator 10 includes a removable diaphragm 28 adjacent distal end 14. (As used herein, the term “adjacent” is meant to include its broad meaning of “near” or “proximal to”, which may, but not necessarily be “bordering on” or “contiguous with”). The diaphragm 28 can be designed with a frangible perimeter for easy removal thereof. With specific reference to FIG. 2, the inside of the frangible diaphragm 28 can be provided with raised reinforcing elements to assist in ensuring that the diaphragm 28 can be removed as a unit. These reinforcing elements can include a peripheral ring 30 and radial spokes 32. The area of weakness that forms the frangible perimeter is formed just outside of the peripheral ring 30. Being best seen in cross section, the area of weakness is further described below with regard to FIG. 5.

[0025] The round inside surface of the duct terminator includes two sections of different internal diameters, separated by a step 32. The proximal section 34 has a length LA and an average internal diameter IDA. The distal section 36 has a length LB and an average internal diameter IDB, which is less than IDA. The internal diameters IDA, IDB are described as average values because the sections 34, 36 are each produced with a slight taper, which can be less than 0.40 degree and preferably about 0.25 degree. The taper is desirable to facilitate ejection of the part from the tool when the part is molded. However, it is also desirable to keep the taper slight so that the inside of the terminator 10 can snugly receive a conduit, which is not tapered. Thus, the smallest taper that permits easy ejection from the mold tool is generally the most desirable.

[0026] The IDA of the proximal section 34 is selected to receive a conduit of a first outer diameter. Preferably, the IDA is selected to receive schedule 40 or schedule 80 conduit, which have different inner diameters, but the same outer diameter. To make the preferred IDA, Section 34 can be produced with an internal diameter at the small end of from 4.500 to 4.510 inches.

[0027] The IDB of distal section 36 is selected to receive a conduit of a second outer diameter that is smaller than the first outer diameter. Preferably, the IDB is selected to receive C-Duct type conduit, which is commonly used for telecom applications. To make the preferred IDB, Section 36 can be produced with an internal diameter at the small end of from 4.350 to 4.360 inches.

[0028] The respective lengths LA and LB of the sections 34 and 36 can be of different lengths, but are preferably of substantially equal lengths. In a preferred embodiment, each of the lengths LA and LB are approximately 3.8 cm (1.5 inches). Thus, approximately 3.8 cm of contact can be achieved between the inside of the duct terminator 10 and the conduit, regardless of whether the conduit has the first outer diameter or the second diameter. (Keeping in mind the taper of the internal diameters of the sections 34, 36, it is understood that the term “contact”, as used herein, does not require precise uniformity.) It is also possible to produce the terminator 10 with only one section 34 or 36.

[0029] Two mounting rings extend from the distal end of the preferred duct terminator 10. The mounting rings include an inner mounting ring 38 and an outer mounting ring 40. The mounting rings 38, 40 together form a receiving groove for accepting a supplemental component of the duct terminator system. Before describing the supplemental components, some of the advantages of the present invention relating to the molding tools and process of molding the duct terminator 10 will now be described.

[0030] The duct terminator can be injection molded from rigid PVC or the like. Having only a single circumferential collar 18 eliminates the need for side actions in the molding process, which are necessary in forming a conventional plastic duct terminator. The L-shape of the collar 18 provides functionality and part strength. The longitudinal ribs 24, 26 are inline with the mold action. These features provide additional part strength with minimum tool complexity. In addition, because the duct terminator 10 can be produced with ribs inline with the mold action and without side action due to the single collar 18, multiple duct terminator 10 parts can be produced using a multi-cavity tool in the same machine, further lowering part cost.

[0031] Another advantage of the preferred duct terminator 10 is that various features can be molded relatively thin. For example, the circumferential rib 18 can be thin because of the manner in which the duct terminator 10 can be injected from the mold tool. After the part has been injection molded between a male and female mold tool and the tools are separated, the part tends to remain on the male mold tool. The part can be pushed off the tool using ejector pins built into the male tool. The ejector pins can be positioned to push against the circumferential collar 18 at points 42 immediately opposite distal longitudinal ribs 24. (There may be provided as many ejector pins as there are distal longitudinal ribs, or there may be provided as few as two or three, as desired.) Thus, when the ejector pins actuate to push the part, the points of contact 42 are well supported by the distal longitudinal ribs 24. Due to the excellent support provided by the ribs 24 and the stability of the collar provided by its L shape, the collar 18 can be made quite thin, while still having adequate strength.

[0032] A further advantage achieved using the inventive molding process is the small degree of taper needed. As noted above, the inside sections 34, 36 of the preferred duct terminator 10 have a small taper of less than 0.40 degree, and preferably about 0.25 degree. The push force of the ejector pins can be applied at points 42 on the collar 18, which is closer to the proximal end 16 than it is to the distal end 14. (The position of the collar 18 relative to the ends 14, 16 is most evident in FIG. 5.) Thus, as the part is pushed off of the male tool in the direction of arrow “Pin Force” (FIG. 2), the force along most of the length of the inside surface in contact with the tool, including all of LB and a portion on LA, is a pushing force, rather than a pulling force. The arrow “Pin Force” is intended to be pointing into the page parallel with the longitudinal axis of the terminator 10. Under such a pushing force, the part tends to expand slightly, making ejection relatively easy. (In contrast, a conventional duct terminator is ejected from a male tool primarily with a pulling force, which tends to cause constriction similar to that of a child's finger trap toy.) Because the pushing force facilitates ejection without substantial part constriction, a large degree of taper to the inside diameter is not necessary. Thus, the duct terminator 10 can be produced with a small taper of less than 0.40 degree.

[0033] As shown in FIG. 3, a first supplemental component of the duct terminator system can be a terminator seal 50. The seal 50 is a deformable, elastomeric member, formed from flexible PVC or the like, which in use will compress to fill space between the distal end 14 of the terminator and a form wall. The seal 50 includes a connecting ring 52, which is sized to be slightly larger than the space between the inner 38 and outer 40 mounting rings of the duct terminator. The seal 50 also includes a bell or parabolic shaped portion 54 for deforming against a form wall. An internal support structure 56 may be integrally molded with the seal if desired.

[0034] As shown in FIGS. 4 and 5, in use, the seal 50 can be engaged with the duct terminator 10 by inserting the connecting ring 52 between the inner and outer mounting rings 38, 40. During insertion, the connecting ring 52 compresses between the mounting rings 38, 40. The inward facing edges of the rings 38, 40 may be beveled, as shown in the drawings, to assist with insertion. Once inserted, the tendency of the connecting ring 52 to expand back to its initial size tends to hold the connecting ring in place between the mounting rings 38, 40.

[0035] The duct terminator 10 and seal 50 may be sized such that the combination is appropriate for use in a form constructed to pour a four inch concrete wall. When installed in such a form, the seal 50 can deform so that the combined unit fits the form with very good precision. After the wall has been poured and cures, the seal 50 can be deformed away from the concrete and removed from the wall if desired. The engagement of the seal connecting ring 52 with the inner and outer mounting rings 38, 40 prevents the seal from becoming locked in the concrete. Thus, the seal 50 can be reused several times prior to it being discarded (or left permanently in a cured wall).

[0036] Referring specifically to FIG. 5, it will now be explained how the removable diaphragm 28 can be removed after a wall has been poured and it is desired to run cables or wires through the wall. As described above, the terminator 10 is formed with an area of weakness adjacent (immediately outside of) the peripheral ring 30 of the diaphragm 28. The area of weakness is identified in FIG. 5 by reference numeral 44, which is an area disposed between the peripheral ring 30 on the inside of the frangible diaphragm and the outer mounting ring 40. The area of weakness can be thinned to about thirty thousandth of an inch to create the shear point 44 around the perimeter of the diaphragm 28.

[0037] Once the diaphragm 28 has been removed or “knocked out”, the inside surface of the outer mounting ring 40 can become the inner most (i.e., radially closest to the longitudinal axis) portion of the duct terminator 10, because the inner mounting ring 38, spokes 32 and peripheral ring 30 are removed along with the diaphragm 28. The radial distance between the inside surface of distal section 36 and the inside surface of the outer mounting ring 40 (if it were extended into distal section 36) can be proportioned to replicate the thickness of a conduit having the above-mentioned second diameter, such as a C-Duct conduit. Thus, if such a conduit is inserted into the section 36, the inside surface of the outer mounting ring 40 will replicate an extension of the inner diameter of the conduit.

[0038] Another advantage of the combined terminator 10 and seal 50 is the concrete coverage that forms around the distal end 14 of the terminator when the structure is poured. Concrete can fill around the tubular body 12 and around the distal end 14, contacting the outer mounting ring 40. This concrete fill creates a stable ring of concrete around the distal end 14. The stable ring of concrete is advantageous because, in use, a builder can insert conduit into the proximal end 16 of the terminator 10 using forceful means, such as hammering the conduit with a heavy object from outside of the structure. The stable ring of concrete at the distal end 14 helps support the terminator 10 under the force, thereby helping to ensure that parts of the terminator do not break under the force. Otherwise, parts of the terminator and bits of concrete could become dislodged from the structure under the hammering force, ending up on the floor inside the structure.

[0039] Convenient sizes for the combined terminator and seal include a length of 4 inches or 2½ inches (which can be slightly less than 4 inches or 2½ inches to provide room for an attachment device, such as a piece of plywood, inside a four-inch wide form) and an approximate internal diameter of 4, 5 or 6 inches. Others lengths and diameters are also possible.

[0040] Additional supplemental system components can be provided so that the same terminator 10 can be used with forms for thicker walls. Such additional supplemental components can be made of PVC or other plastic material and can include an extender 60 shown in FIG. 6, or a bell 80 shown in FIG. 7. Both the extender 60 and bell 80 are adapted to connect to the duct terminator 10. One or more extenders 60 and bell 80 can also be used in combination as shown in cross section in FIG. 8.

[0041] The extender 60 includes a tubular body 62 with a distal end 64 and a proximal end 66. The proximal end 66 is adapted to engage the distal end 14 of the terminator 10 by gripping the outside of the outer mounting ring 40. If desired, the junction between the proximal end 66 of the extender and the distal end 14 of the duct terminator can be glued.

[0042] The proximal end 66 of the extender can include a circumferential L-shaped collar 68 that is similar to the collar 18 of the duct terminator 10. The extender 60 can also include longitudinal ribs 70 that are similar to the distal ribs 24 of the terminator 10. These features provide the extender 60 with support and strength so that the amount of plastic used to mold the part can be minimized.

[0043] The distal end 64 of the extender 60 can be made with inner and outer mounting rings 72, 74 that replicate the mounting rings 38, 40 at the distal end 14 of the terminator 10. Similar to that of the terminator 10, the inner mounting ring 72 can be mounted on a removable diaphragm 76, which, if desired, may be made with the same features described above with regard to diaphragm 28. The diaphragm 76 can be removable at an area of weakness. In FIG. 8, the diaphragm 76 has been removed from the extender 60. The area of weakness where the diaphragm was attached (prior to removal) is identified by the numeral 78.

[0044] If the duct terminator 10 has a length that is proportioned to fit, in combination with the seal, a form for a four inch wall, the extender can be formed with a length so that the combination of a duct terminator 10, extender 60 and seal 50 fits within a form for pouring a six inch wall. Two extenders 60 can be used if an eight inch wall is to be poured.

[0045] The bell 80 includes a distal end 82 and a proximal end 84. The proximal end 84 is adapted to engage the distal end 14 of the terminator 10 or the distal end 64 of the extender 60. The bell 80 engages the distal end of either part by gripping the outside of the outer mounting ring 40 (of the duct terminator) or 74 (of the extender). If desired, the junction between the proximal end 84 of the bell and the distal end 14 (of the duct terminator) or 64 (of the extender) can be glued.

[0046] The distal end 82 includes a bell or parabolic shape to provide a curved surface in a concrete wall for cables passing through the wall. Such a surface may be desirable, for example, if the cables have a limited bending radius. If the cable must be terminated near the point of entry, it is, therefore, desirable to begin the turn in the cable toward the point of termination at the curved surface provided in the wall.

[0047] The duct terminator 10, seal 50, extender 60 and bell 80 can be provided individually or as part of a modular duct terminator system that allows a vault builder to accommodate vault walls of various sizes while stocking only a few parts. This is possible by providing the duct terminator with a universal mounting structure on the distal end, such as the mounting rings described above. The supplemental system components each have a connecting structure on a proximal end adapted to connect with the universal mounting structure, such as the connecting ring of the seal or the proximal ends of the extender walls. Because the extender can be formed with a distal end that replicates the universal mounting structure, one or multiple extenders can be stacked and used in combination with the duct terminator and/or other supplemental components.

[0048] A variety of modifications to the embodiments described will be apparent to those skilled in the art from the disclosure provided herein. Thus, the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.