WO1992017725A1 - Elements coudes pour ensembles de confinement a canalisations doubles - Google Patents

Elements coudes pour ensembles de confinement a canalisations doubles Download PDF

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Publication number
WO1992017725A1
WO1992017725A1 PCT/US1992/002684 US9202684W WO9217725A1 WO 1992017725 A1 WO1992017725 A1 WO 1992017725A1 US 9202684 W US9202684 W US 9202684W WO 9217725 A1 WO9217725 A1 WO 9217725A1
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WO
WIPO (PCT)
Prior art keywords
fittings
pipe
elbow
fitting
straight
Prior art date
Application number
PCT/US1992/002684
Other languages
English (en)
Inventor
Christopher G. Ziu
Original Assignee
Double Containment Systems
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Double Containment Systems filed Critical Double Containment Systems
Priority to CA002107562A priority Critical patent/CA2107562A1/fr
Publication of WO1992017725A1 publication Critical patent/WO1992017725A1/fr

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L39/00—Joints or fittings for double-walled or multi-channel pipes or pipe assemblies
    • F16L39/005—Joints or fittings for double-walled or multi-channel pipes or pipe assemblies for concentric pipes

Definitions

  • the present invention relates to double containment pipe fittings and their assembly.
  • the present invention provides novel double containment fittings for forming a double containment pipe joint.
  • the products that have been developed to date have not completely addressed some of the unique problems that arise when a pipe is placed within another pipe.
  • a double containment piping system that is constructed of an interconnecting part as described above, actually increases the chance that failure to the external environment can occur as compared to a singular containment piping system designed with proper treatment of the thermal expansion of its components.
  • Another problem with existing systems has to do with the ability to combine different inner and outer pipe materials in an efficient manner.
  • Different materials can mean materials that are of a different class, (such as metallic-thermoplastic, metallic-reinforced thermosetting plastic, or thermoplastic-reinforced thermosetting plastic) , or materials that are within the same class but constitute a different material, (such as within the thermoplastic family, combining a fluoropolymer within a polyolefin, or a polyolefin within another polyolefin) .
  • Piping elbows have been used ever since the first pipe systems were used, and are considered to be a basic component of the piping system.
  • Standard elbow patterns have been created and established that are used in the majority of all piping applications. For butt-welded systems, the standard elbow patterns involve short radius elbows (radius of the elbow is approximately equal to the nominal diameter of the pipe) , long radius elbows (radius of the elbow is approximately equal to 1-1/2 times the nominal diameter of the pipe) and for sanitary applications elbows that have a radius equal to approximately four times the nominal diameter. While these elbows have long served a purpose for singular piping systems, the use of standard size elbows in double containment piping systems present many potential problems.
  • elbows may not be capable of being readily fabricated into an inner and outer arrangement, while maintaining the concentricity of the pipes leading into the elbow. Even if the elbows do fit, they will likely not be positioned in a perfectly concentric arrangement when placed in the outer elbow. That will mean that the inner elbow will be positioned in a less than ideal space relationship with respect to the outer. The allowable room for movement will therefore be less than the ideal relationship, where the inner elbow is perfectly positioned at any one given pipe within the outer. If the elbows contact each other due to a differential movement of the elbows, severe problems can occur.
  • the inner and outer elbows will be subjected to a displacement strain and will experience a concentration in stress.
  • the outer elbow may fail under this strain, creating a breach in the secondary containment.
  • the inner elbow may also subsequently occur, resulting in a breach of the primary containment and a subsequent double failure. Even if the elbow itself doesn't fail, failure can result at joints, or even in straight pipe sections due to excessive bending and torsional loads. These can also lead to a double failure.
  • the elbow system employed in the present invention has many benefits over the current practice of using existing standard fittings for attachment to their respective pipes, as shown for example in U.S. Patent Nos. 4,786,088, 4,886,305 and 4,930,544.
  • a standard radius pattern can be used as the basis for the primary and secondary containment fittings. This will allow some conformity to conventional elbows, although the conventional elbow styles are not intended to produce adequate flow conditions in a double containment piping system.
  • the elbow concept of the present invention also has benefits beyond its technical advantages. It also allows the double containment piping assembly to be assembled and welded (bonded) together in a much more efficient and easy manner. All elbows could be field assembled and provide modular sections which can be individually repaired, replaced and inspected.
  • the angle of the sector of both the inner or primary pipe and the outer or containment pipe of both fittings should be equal.
  • the annular space between the fittings should be consistent or the same throughout the curvature and length of the fittings. Either end of the inner and/or outer fittings or both ends of one of the fittings can be provided with a straight portion extending beyond the end of the other fitting. This will save several steps in the overall fabrication of the double containment pipe assembly in that it allows the ability to use the same length of inner and outer pipes between elbows, or between elbows and other fittings.
  • FIGURE 1 illustrates the concentric elbow pipe fittings used to form the double containment pipe assembly of the present invention, with portions indicated in phantom lines comprising optional straight line extensions of the fittings enabling ease of field or shop fabrication of the elbow fittings in the double containment pipe assembly;
  • FIGURE 2 illustrates another form of the concentric elbow pipe fittings
  • FIGURE 3 is a cross-sectional view illustrating the use of a pair of elbow pipe fittings of FIGURE 1 in a double containment pipe assembly of the present invention
  • FIGURE 4 is a cross-sectional view illustrating the use of a pair of elbow pipe fittings of FIGURE 2 in a double containment pipe assembly of the present invention
  • FIGURE 5 is a cross-sectional view illustrating a concentric elbow pipe fitting wherein the inner pipe has straight line extensions at either end; and
  • FIGURE 6 is a cross-sectional view illustrating the f the elbow fitting of FIGURE 5.
  • elbow fittings of the present invention are indicated by the numeral 10 and 12 and are used as a connection between straight portions of a double containment pipe assembly (not shown) .
  • the outer or containment pipe elbow 10 and the inner or primary elbow 12 have the same radius of curvature or occupy the same angle ⁇ of the sector of a circle and are concentrically located with the inner or primary pipe in the outer or containment pipe 12 so that the annular space between the outer surface of the inner pipe 12 and the inner surface of the outer pipe 10 is constant, or the same throughout the radius of curvature or sector.
  • the end face 14 of the inner pipe 12 and the end face 16 of the outer pipe 10 are adapted to be connected to the inner and outer corresponding straight sections of a double containment pipe assembly, respectively.
  • This can be accomplished in a number of manners, but, the most usual way is to butt weld the straight section of each pipe to the end face 14,16, respectively, as illustrated in FIGURES 3 and 6.
  • the inner and outer pipes 10',12' may be formed with sockets or flanges 14 ' , 16 ' along their end face extending in the direction of the pipe to be joined, for nesting engagement with the inner and outer pipes, as illustrated in FIGURE 4. In some instances, this will ease the fabrication of the double containment pipe assembly, particularly in the field.
  • either end of the inner or outer pipe fitting elbow 12,10, respectively may be formed with a straight extension portion 18 and 20, respectively.
  • the inner pipe fitting elbow has straight extensions 18. It is desirable that the straight portions of the inner section be at one end and the straight portions of the outer section at the other, or vice versa, (e.g., see straight sections 18',20' of the elbow fittings of FIG. 2) , or the straight sections be at both ends of the inner or outer pipes (see FIGURES 5 and 6, for example) , so that during fabrication of the double containment pipe assembly, equal lengths of the straight pipe sections can be used for the inner and outer pipes between the elbows and other containment fittings, as illustrated in FIGURES 3 and 6. This enables standardization to be achieved for the system.
  • the inner/outer pipe can have or be provided with the straight portions at both of its ends, if desired, and the standardized system could have one length of inner and one length of outer pipe.
  • the material can be matched to the inner and outer pipe material of the straight length sections between elbow fittings.
  • the portions of the double containment assembly between elbow fittings can be modular in that, if a leak occurs, it is only necessary to repair and replace one section of the pipe assembly.
  • Utilizing concentric elbow fittings enables the maximum spacing to be achieved between the fittings so as to provide for thermal expansion and contraction without potential contact between the fittings which may cause disruption or cracking, and by utilizing such a system, improved flow through the system is achieved along with more uniform heat transfer.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)
  • Thermal Insulation (AREA)

Abstract

Ensemble de confinement à canalisation double possédant des parties courbées constituées d'éléments coudés (10, 12) s'étendant entre les parties droites d'un ensemble de canalisations concentriques interne et externe. Les coudes (10, 12) occupent le même secteur angulaire d'un cercle et sont concentriques entre eux. L'écartement entre les surfaces interne et externe courbées des coudes (10, 12) est égal et identique sur la totalité du rayon de courbure des coudes. Ceci assure une protection maximale contre tout contact entre les coudes interne et externe (10, 12) lors de la dilatation et de la contraction thermiques de la canalisation. On peut fixer les parties droites (18, 20) de la canalisation à des faces opposées (14, 16) des coudes afin de faciliter la fabrication dudit ensemble de confinement à double canalisation là où il sera utilisé. On peut fixer les parties droites aux faces terminales (14, 16) des coudes en les soudant bout à bout ou au moyen des techniques de soudage bout à bout enroulé, ou bien en les emboîtant dans des douilles (14', 16') prévues au niveau des faces terminales.
PCT/US1992/002684 1991-04-04 1992-04-03 Elements coudes pour ensembles de confinement a canalisations doubles WO1992017725A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA002107562A CA2107562A1 (fr) 1991-04-04 1992-04-03 Raccords coudes pour tuyauterie sous enveloppe

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US68132491A 1991-04-04 1991-04-04
US681,324 1991-04-04

Publications (1)

Publication Number Publication Date
WO1992017725A1 true WO1992017725A1 (fr) 1992-10-15

Family

ID=24734791

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1992/002684 WO1992017725A1 (fr) 1991-04-04 1992-04-03 Elements coudes pour ensembles de confinement a canalisations doubles

Country Status (4)

Country Link
EP (1) EP0580799A4 (fr)
AU (1) AU1797192A (fr)
CA (1) CA2107562A1 (fr)
WO (1) WO1992017725A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120100496A1 (en) * 2007-08-06 2012-04-26 Anne Boer Burner
US20240093820A1 (en) * 2022-09-16 2024-03-21 K.D.W. Company Limited Double containment fittings for connecting double containment tubing

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2002470A (en) * 1935-05-21 Method of making elbow pipe ftc
US2761949A (en) * 1954-09-29 1956-09-04 Fluid Systems Inc Prefabricated pipe system
US4786088A (en) * 1987-06-25 1988-11-22 Asahi/America, Inc. Double-containment thermoplastic pipe assembly
US4886305A (en) * 1988-08-12 1989-12-12 Fibercast Company Double containment pipe fittings and apparatus to adhesively install the same

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE399192C (de) * 1920-05-31 1924-07-28 Cfcmug Rohrverbindung fuer konzentrisch ineinanderliegende Rohrleitungen
AT388790B (de) * 1988-02-08 1989-08-25 Vaillant Gmbh Doppelrohr, sowie verbindung koaxialer doppelrohrschuesse mit einem aus einem solchen doppelrohr bestehenden verbindungsstueckes
DE3836326A1 (de) * 1988-10-25 1990-04-26 Tscherwitschke Gmbh Richard Verbindungsstueck zum verbinden wenigstens zweier in verschiedene richtungen verlaufender, insbesondere aus thermoplastischem kunststoff bestehender rohrleitungen sowie ein verfahren zur herstellung des verbindungsstuecks
AT395055B (de) * 1990-02-20 1992-09-10 Vaillant Gmbh Verbindungsbogen

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2002470A (en) * 1935-05-21 Method of making elbow pipe ftc
US2761949A (en) * 1954-09-29 1956-09-04 Fluid Systems Inc Prefabricated pipe system
US4786088A (en) * 1987-06-25 1988-11-22 Asahi/America, Inc. Double-containment thermoplastic pipe assembly
US4886305A (en) * 1988-08-12 1989-12-12 Fibercast Company Double containment pipe fittings and apparatus to adhesively install the same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP0580799A4 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120100496A1 (en) * 2007-08-06 2012-04-26 Anne Boer Burner
US20240093820A1 (en) * 2022-09-16 2024-03-21 K.D.W. Company Limited Double containment fittings for connecting double containment tubing
US11982389B2 (en) * 2022-09-16 2024-05-14 K.D.W. Company Limited Double containment fittings for connecting double containment tubing

Also Published As

Publication number Publication date
AU1797192A (en) 1992-11-02
EP0580799A4 (en) 1994-05-11
EP0580799A1 (fr) 1994-02-02
CA2107562A1 (fr) 1992-10-05

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