Patent Application
20120255345
The present invention relates to methods and systems for verifying and ensuring the integrity of a piping system that uses a sealant material in its joint assemblies to form fluid tight sealed joint connections or assemblies. More specifically, the methods and systems are provided for detecting a joint connection in the system without a sealant material (a dry fit connection), or a joint connection in the system with an insufficient amount of sealant material, each of which define an improperly sealed joint connection. In addition, the methods and systems herein provide means for identifying the location of an improperly sealed joint connection. Included are products for forming the joint assemblies; these products further form a detectable leak path in an improperly sealed joint connection through which fluid can be exchanged between the interior of the joint connection and the exterior of the joint connection.
There are a variety of piping system applications in which maintaining a fluid-tight seal at the various piping connections and junctures are believed to be of critical importance to the operation and maintenance of the piping system. Some piping systems use a chemical weld in a socket-type connection between piping elements to form a joint assembly. In a socket-type connection, tight tolerances between piping elements tend to form an interference or “dry fit” between interfacing surfaces. To form a fluid-tight sealed and permanent joint connection, a sealant material or solvent cement is applied to the components to seal their connection by way of, for example, a chemical weld, material melding, bond or other interconnection. Failure to apply any sealant material, or at least an adequate amount of sealant material, can render the dry fit joint connections or assemblies of the system susceptible to leakage. However, the dry fit formation between the engaged surfaces of the pipe element can mask an improper seal in the joint connection, and the assembly can at least temporarily hold fluid pressure. This can create a problem because pressure surges, the passage of time, and/or vibration can cause these dry fit connections or connections without an appropriate amount of sealant material (partial seals) to fail.
Even minor leaks from improperly sealed joint connections or assemblies can cause damage to the surrounding property or environment. For example, in a fire protection system and, more specifically, a residential fire protection system, joint assemblies are formed by chemical welding a socket-type connection between piping elements such as, for example, a pipe end inserted into a pipe coupling socket, each of which is made from a plastic such as Post Chlorinated Polyvinyl Chloride (CPVC). If a dry fit/partial seal connection in such a system is improperly sealed, goes undetected, and is placed into service, property damage and in particular personal property damage can result should the dry fit/partial seal connection fail.
As a matter of practice, a fire protection piping contractor or installer initially assembles the pipe elements to check the dry fit/partial seal, disassembles the connection, applies the sealant about the outer surface of the pipe and the inner surface of the socket, rejoins the elements and allows the sealant to cure. In a residential application of 1,000 square feet, 75-100 socket type connections may be present each requiring application of the sealant material. Due to the large number of fittings present and/or human error, some connections do not receive any sealant or at least a sufficient amount of sealant. Accordingly, it is desirable to perform a static fluid or leak test upon the piping system before placing the system in service. If the system holds fluid pressure, the system is placed into service and the construction of the residence is completed. However, as noted above, in the absence a sealant material or an adequate amount of sealant, a joint connection can pass the leak test due to the dry fit/partial seal between the piping elements which can give a false passing result in the leak test.
Moreover, pneumatic or hydrostatic testing of a pipe joint connection can present a hazard to installers or other contracting personnel. In some instances, a dry fit connection can form a dry fit capable of holding liquid or gas which can result in the build up of pressure within a segment of the piping system around the joint. During pneumatic or hydrostatic testing, a dry fit joint connection may eventually reach a threshold pressure and fail. The sudden release of internal pressure and its potential energy may be sufficient to propel, for example, an end cap or other pipe segment away from the pipe end; thereby making the pipe fitting a projectile capable of causing property damage and/or personal injury.
The present invention provides methods and systems for the assembly, construction and testing of piping systems that incorporates a joint connection or assembly capable of indicating an improper seal. Preferably, the joint assembly is configured for piping systems that employ socket-type fittings with a flowable sealant material to seal the joint assembly. In particular, the preferred joint assembly is unable to hold fluid pressure if the joint assembly is improperly sealed. In particular, the preferred joint assembly is unable to hold fluid pressure as a dry fit connection or as a partial seal. More specifically, the joint assembly includes a preferred coupler, i.e., a pipe fitting, a pipe end fitting or a modified pipe surface for joining piping segments, that includes a channel to form a leak path in cooperation with the pipe segment surface in an improperly sealed joint connection. Fluid can escape through the channel to identify to a piping system installer, contractor, owner or operator (collectively “operating personnel”) the improper seal, and in particular the absence of a sealant material to form the proper seal in the joint assembly. Accordingly, described herein are methods and systems for detecting and sealing dry fit connections in a piping assembly. Moreover, the inventors' couplers prevent the build up of fluid pressure around a dry fit joint connection absent any or a proper amount of sealant material. By eliminating the ability of a dry fit connection to hold fluid pressure, the connection cannot store potential energy and thus the potential for harm to the surrounding environment and personnel from a dry fit or partial seal connection is eliminated.
In one preferred embodiment, a method is provided for detecting a leak in a pipe assembly. The method includes providing at least one fitting having a channel defining a leak path, pneumatically testing the assembly, and then hydraulically testing the assembly. A method provides for checking the integrity of a fire protection piping system having a plurality of couplers. The method includes pressurizing the piping system, detecting a leak in the piping system, the detecting including flowing fluid from at least one channel in the coupler, sealing the at least one channel, and rechecking the system for a leak. The flowing of fluid includes disposing at least one coupler about at least one pipe segment including placing the at least one channel in communication with the central passageway of the at least one piping segment. Placing the channel in communication with the central passageway further includes defining the depth, width and length of the at least one channel along an inner surface of the coupler. Detecting a leak preferably includes monitoring a pressure drop in the system, and identifying the at least one coupler from which fluid is flowing. Part of the preferred method includes applying a sealant to the coupler and the pipe segment and further altering the channel so as to form a fluid tight seal about the pipe segment.
A method is provided of leak testing a piping system having at least one joint assembly including a pipe fitting with a pipe segment disposed in the fitting. The method includes defining a leak path between the pipe fitting and the pipe element, introducing fluid into the system, and detecting fluid discharge from the leak path. Accordingly, a method of detecting a leak in a pipe assembly preferably includes providing at least one coupler attached to a pipe segment to form the assembly. The coupler includes a channel to define a leak path. The method further includes flowing fluid through the channel so as to detect leak between the at least one fitting and the pipe segment. More preferably, the method provides pressure testing the assembly pneumatically, and pressure testing the assembly hydrostatically, or alternatively, the method can consist of one of pneumatic and hydraulic pressure testing. The detecting of fluid discharge, in the presence of the leak path, includes detection of a pressure drop in the system within a preferred time such as, for example, two minutes of initiating pressure testing. Moreover, wherein introducing the fluid includes pressurizing the system with air to an initial pressure of 10 psi, the pneumatic testing preferably includes detecting a pressure drop in the system through the leak path. The pressure drop having an initial minimum rate of about 0.5 psi per minute. Under the hydraulic pressure testing using an initial pressure of 10 psi, the hydraulic testing includes detecting a minimum 0.5 psi/2 min across all the modeled occupancies.
To facilitate leak detection, a preferred coupler is provided for forming a joint assembly in a fire protection piping system, the coupler includes a substantially tubular wall portion having an outer surface and an inner surface defining a passageway extending along an axis. The coupler further includes an end face extending between the inner surface and the outer surface to define a thickness of the tubular wall portion. A channel is disposed along one of the inner and outer surfaces and in communication with the passageway. The channel has a first configuration for carrying a fluid between an interior of the piping system and an exterior of a piping system. The channel has a second configuration to prevent fluid from being carried between the interior and the exterior of the piping system. The channel is further preferably convertible from the first configuration to the second configuration in the presence of a minimum amount of sealant material. Where the system has an initial internal pressure of about 10 psi of air, the channel in the first configuration provides for decrease in the system pressure at a preferred initial minimum rate of about 0.5 psi per minute. Under the hydraulic pressure testing at 10 psi, the channel configurations preferably provide an initial minimum rate of pressure change of 0.5 psi/2 min.
Further provided is a coupler having an outer surface and an inner surface defining a central passageway along a longitudinal axis. An annular shoulder is engaged with the inner surface and extends radially inward toward the longitudinal axis. The shoulder includes a pair of sidewalls to define an axially extending channel in communication with the central passageway. The channel is preferably alterable to define a fluid-tight seal about a segment. The pair of sidewalls defines a channel depth of the channel in a direction along the longitudinal axis. Preferably, the channel depth is at a maximum at the shoulder, and the coupler further includes a first end face and a second end face. The inner surface further includes an interconnecting surface connecting the pair of sidewalls, the interconnecting surface is substantially radiused relative to the interior of the channel. In one embodiment, the channel can progresses helically about the longitudinal axis. In another embodiment, the channel includes a portion that is configured as a through hole extending from the inner surface and the outer surface and in communication with the remainder of the channel. Alternatively, the entire channel can be defined by a through hole extending from the inner surface to the outer surface substantially perpendicular to the axis of the coupler. In a further embodiment, the coupler further includes a projection along the outer surface so as to define a constant wall thickness through the inner surface and the outer surface.
The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate exemplary embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain the features of the invention.
Shown in
The preferred assembly of the system 10 includes joining two or more pipe elements at a joint assembly 100 using a socket-type coupler with a flowable sealant material, verifying the seal integrity throughout the system and placing the system in service. Shown in
The method further preferably includes verifying the integrity of the system by detecting a leak. Preferably, a positive pressure is placed on the system 10, but may alternatively a negative pressure may be placed on the system 10. The method of detecting can include a direct method of leak detection by, for example, observing a leak from one or more joint assemblies 100 after pressurizing the system 10. Alternatively or in addition to, the method of detecting can include an indirect method of leak detection by monitoring one or more pressure gauges coupled to the system 10 for monitoring a pressure loss in the system. If a leak is detected, the preferred method of assembly can include repairing and sealing the leak and re-verifying the integrity of the system 10. If no leak is detected, the system 10 can be placed into service.
A preferred coupler provides means for detecting a leak in a pipe system 10 for use in the preferred method of assembly. More specifically, the preferred coupler, in the absence of an appropriate seal and under positive pressure, directs movement of a fluid from the central interior passageway of the pipe assembly to the exterior environment proximate the pipe assembly through a leak path at least in part defined by the coupler and defined in total by the cooperation between the coupler and the pipe segments. Under a negative pressure and in the absence of an appropriate seal, the preferred coupler continues to draw external atmosphere through the channel. Preferably, the leak path is configured to prevent the pipe system 10 from holding pressure in the absence of an appropriate seal. Operating personnel that detect that the system's failure to maintain a static pressure are thereby alerted to the possibility an improper seal in the joint connections. An improper seal can be a joint connection in which no sealant material is present or where some sealant material, but an insufficient amount, has been applied.
Upon construction of a pipe system 10 having the preferred couplers, the operating personnel verify the integrity of the system 10 by evaluating whether a leak path is formed through which fluid can flow between the system interior and exterior. Specifically, the operating personnel preferably pressure test the piping system in stages. In the first stage, the piping system 10 is pneumatically tested over a pressure range or value, for example, from about, preferably, 1 pound per square inch (psi) to about 15 psi, and preferably at a value of 15 psi The system 10 is checked for the compressed air or gas leaking from preferred couplers using direct and/or indirect visual, tactile or audible means. The operating personnel may then properly seal any improperly sealed joint assemblies 100 that were detected, and after which, the operating personnel can again pneumatically test the system over the preferred pressure range or value, from about, preferably, 1 pound per square inch (psi) to about 15 psi, and preferably at a value of 15 psi, to verify that the repairs were satisfactory.
A second stage of pressure testing preferably includes hydraulic testing and more preferably hydrostatic testing of the system 10, at a preferred pressure of about 200 psi. More preferably, the second stage of pressure testing provides for hydraulic testing at hydrostatic testing pressures as defined in National Fire Protection Association (NFPA) Standard NFPA-13, Chapter 24 (2007), entitled, “Standards for Installation of Sprinkler Systems: Systems Acceptance,” which is incorporated by reference in its entirety.
After pressurizing the system to the desired hydrostatic testing pressure, the system can be checked for liquid discharge from the preferred couplers using direct and/or indirect visual, tactile or audible means. The operating personnel can again properly seal any improperly sealed joint connections that were further detected under the second stage of pressure testing, and then may again preferably hydraulically test the system under the preferred hydrostatic pressure range. It should be understood that any pressure range or specific pressure value can define the initial pneumatic pressure range or the hydraulic pressure range, provided that the initial pneumatic and hydraulic pressures are sufficient so as to move the corresponding fluid from the central interior passageway of the pipe assembly to the exterior environment proximate the pipe assembly through the leak path at a rate that is detectable by direct or/indirect means. It should be further understood that the operating personnel provide for an appropriate amount of time between performing any sealing operation and pressure test to allow sufficient time for the sealant to weld, meld, bond or otherwise form the joint connection. With all the joints properly sealed and the system checked for its integrity, the system can be filled with water or other fluid and placed into service.
Alternatively to performing the second stage of hydraulic pressure testing after the initial pneumatic test, a second stage of pneumatic testing can be performed in which the testing pressure is increased or greater than the initial test pressure test stage provided the second pneumatic test pressure is suitable for the piping application. Again, the system can be checked for the compressed air or gas leaking from the preferred couplers using direct and/or indirect visual, tactile or audible means. The operating personnel can again properly seal any improperly sealed joint connections that were further detected under the higher pressure range, and then they may again pneumatically test the system under the test pressure for the second stage.
The preferred couplers provide a substantially rapid and verifiable mechanism for detecting an improperly sealed joint connection in a piping system. More specifically, the preferred couplers are configured with a channel that, in the absence of a proper seal, provides for a leak path through which fluid can immediately flow between the interior of the system and the exterior of the system 10 to provide at least one of a relatively quick indirect and direct leak indicator for the operating personnel. The compressed liquid, gas, air or other fluid leaking from a preferred coupler's channel, identifies for the operating personnel an improperly sealed joint. Moreover, it is believed that the preferred couplers provide a preferred means with which to perform pressure testing of a piping system 10 preferably in the method described above. In particular, the preferred couplers' channels, in the absence of a proper amount of sealant material, result in detectable pressure drop in the system 10 preferably within two minutes of initiating the system pressure test. Moreover, because the preferred couplers prevent the build up of fluid pressure around an improperly sealed joints, the preferred couplers remove the potential energy around the joined pipe fittings or segments absent a properly formed seal. This mechanism can prevent improperly joined pipe fittings or segments from violently failing or rupturing and becoming projectiles capable of causing property damage and/or serious injury to surrounding personnel.
A preferred coupler for forming a joint assembly 100 with a pipe segment is configured to detect and identify an improper seal assembly by preventing the dry fit connection between the mating surfaces of the pipe segment and the preferred coupler in the joint 100 from holding pressure, absent an adequate amount of sealant material, and instead allows the fluid to escape to atmosphere. In the presence of an adequate amount of sealant material, the preferred coupler forms a fluid tight seal about the pipe segment. The sealant material can be, for example, a cement, solvent cement, epoxy, solder or other flowable material that is used to reconstitute, chemically weld, bond or otherwise permanently join the coupler to one or more piping segments. Exemplary sealant materials for use with the couplers includes (i) Blazemaster CPVC Cement TFP-400 Red Heavy Bodies or (ii) Blazemaster CPVC Cement TFP-500, each described at pages 43-50 of the “Blazemaster®: Installation Instructions & Technical Handbook” (Rev. 0 Jan. 2005), which is incorporated by reference in its entirety, or their equivalents. Because the preferred coupler indicates an improper fluid seal by leaking to atmosphere the fluids conveyed through the joint assembly, the preferred coupler does not permit the build up of pressure around the joint 100 in the absence of a proper chemical seal. Furthermore, the coupler is preferably configured to provide a sufficient interference fit between the joined surfaces of the joint assembly so as to avoid unnecessary pooling of sealant material between pipe elements, as recommended at page 33 of the “Blazemaster®: Installation Instructions & Technical Handbook” (Rev. 0 Jan. 2005).
The preferred coupler includes a substantially tubular wall member defining one or more sockets to receive a pipe segment or element such as a pipe, fitting or adapter. Referring to
Referring to
Referring to
The shoulder 314 preferably extends radially inward toward the central axis A-A by an amount sufficient to present a surface to inhibit the axial migration of a pipe segment toward the center of the fitting yet sufficiently low in profile so as to provide a desired fluid flow therethrough at a desired pressure and/or fluid velocity. Preferably, the shoulder 314 defines an internal diameter D3 of the fitting 300 to be about ninety-four percent of the first diameter D1 or about 1.25 inches and is more preferably about 1.10 inches in diameter. Either surface of the shoulder extending perpendicularly to the central axis A-A can be countersunk such that the shoulder 314 defines another internal diameter D4, which, for example, in the preferred fitting 300, preferably measures about 1.11 inches. The counterbore of the surface is preferably to a depth of about 0.035 inches. The dimensions of the sockets 312a, 312b can further follow the schedule of dimensions shown in Table B entitled “ASTM Dimensions for CPVC fitting in inches” at page 19 of the “Blazemaster®: Installation Instructions & Technical Handbook” (Rev. 0 Jan. 2005) (Addendum #1/IH-1900 (October 2005)), which is incorporated by reference, for a range of nominal size fittings ranging from ¾ inches to three inches. In the alternative, the sockets of the fitting may be correspondingly dimensioned where the nominal size of the fitting varies from about ½ inch to about 18 inches.
The fitting 300 further includes one or more channels 318 to define a leak path for fluid conveyed through the joint assembly 100. More specifically, the fitting 300 preferably includes a channel 318 to define a leak path or passageway over the outer surfaces of the pipe segments 24, 26 through which a gas or liquid contained in the pipe segments 24, 26 can escape to atmosphere. The channel 318 preferably forms a single discontinuity in the interference fit between the preferably smooth circular inner surface 313 and the outer surface of pipe segments 24, 26 so as to be in communication with the central interior passageway 315 of the fitting. Accordingly, the channel 318 is in communication with sockets 312a, 312b such that fluid flowing from the ends of the pipe segments 24a, 24b into the central portion of the interior passageway 315 of the fitting 300 can escape to atmosphere. In forming a fluid-tight sealed joint assembly for service in a piping system, the sealant material, preferably one of (i) Blazemaster CPVC Cement TFP-400 Red Heavy Bodies or (ii) Blazemaster CPVC Cement TFP-500, each described at pages 43-50 of the “Blazemaster®: Installation Instructions & Technical Handbook” (Rev. 0 Jan. 2005), is applied to the outer surface of the pipe segments 24, 26 and along the inner surface 313 of the sockets 312a, 312b. For a given configuration of pipe segments 24, 26 and sockets 312a, 312b, a sufficient amount of sealant material fills, seals, melds, welds, deforms, reconstitutes and/or collectively alters the channel 318 of the fitting 300 so as to prevent the escape of fluid to atmosphere and forms the fluid tight seal about the joint assembly.
Because the channel 318 allows a fluid to escape to atmosphere in the event of an improper seal, the channel 318 provides any one of the joints 100 in the system 10 with an indicator to operating personnel of an incomplete or failed fluid tight joint assembly. More specifically, the operating personnel is made immediately aware of the lack of adequate or complete absence of sealant material in the socket 312a or socket 312b by the direct visual, tactile or audible indication of fluid flowing from either channel 318 and/or the failure of the fitting 300 to maintain pressure. Indirect methods of detecting fluid discharge from the channel 318 can be employed. For example, in the method described above in which operating personnel are pneumatically and/or hydraulically checking the system 10, the operating personnel monitor a pressure gauge to observe whether the system 10 can hold and maintain a given pressure. If the system is unable to hold a constant pressure, the joint assemblies 100 of the system are inspected to determine if fluid was being vented from the channels 318 due to an improper seal at the fitting 300. For example, where the system 10 contains a liquid, a material can be applied to the fitting 300 and as liquid discharges from the channel 318 and contacts the material, the liquid and the material can react to provide a visual or tactile indication of an incomplete seal.
As seen in
The sidewalls 320 of the channel 318 are spaced apart to define a channel width W preferably measuring about 0.045 inches and more preferably about 0.060 inches. The inner surface 313 and the sidewalls 320 further define the depth or height profile H of the channel 318. Preferably, the height of the channel 318 at the end face 310a is about 0.010 inches and more preferably about 0.025 inches. The depth profile H of the channel 318 further preferably increases toward the center of the fitting with the deepest part of the channel being at the shoulder 314, where, for example, in the channel depth H is about 0.07 inches. More specifically with reference to the cross-sectional view of the channel 318 in
The sidewalls 320 of the channel 318 are shown in
Referring to
More preferably, the channel 318 is dimensioned such that the channel or leak path can define a void in conjunction with the outer surface of a pipe segment through which fluid can readily leak and provide a visual indicator of an improper seal, and further form an adequate fluid-tight sealed connection upon application of an appropriate amount of sealant material. The channel volume is preferably defined by the channel length, the channel width W and the height profile H. The total channel volume of the fitting 300 can be further defined by the number of channels 318 radially disposed about a socket 312a, 312b. Although only a single channel 318 is shown at the end face 310b in
Although the channel height H profile and the width W can remain constant over a range of nominal fitting sizes, the channel length, the channel width W and/of the channel height H can vary with the fitting size to preserve a constant dimensional relationship. Where for example, the dimensions of the preferred channel 318 of one socket 312 in the preferred nominal one inch fitting 300 define a height-to-length ratio H:L of about 0.008, the channel length and height H can be dimensioned accordingly for a fitting of lesser or greater nominal size to preserve the preferred ratio. Shown in Table 1b below is an exemplary schedule of dimensions for a channel 318 in which one or more dimension such as, for example, channel width W, vary with the nominal size of the fitting 300.
The preferred fitting 300′ includes two or more sockets 312a′, 312b′ to receive a pipe element such as a pipe, fitting or adapter. The coupler 300′ includes an outer surface 311′ and an inner surface 313′ defining a central passageway 315′ extending along the axis A′-A′. Dividing the sockets 312a′, 312b′ is a circumferential shoulder or ring 314′ preferably formed integrally with the inner surface 313′ and more preferably integrally formed with the fitting 300′. The shoulder 314′ defines a central opening such that the central passageway 315′ is continuous and communication is provided between the pipe segments 24, 26. Preferably, each of sockets 312a′, 312b′ are similarly configured and along with the inner surface 313′ are further configured to form an interference fit at one or more circumferential points with the outer surface of the pipe segments 24, 26. For example, the sockets 312a′, 312b′ are further defined by the preferably tapering inner surface 313′ so as to form a substantially circumferential interference fit about the pipe segments 24, 26. The taper of inner surface 313′ can define an angled surface that limits axial progression of a pipe segment 24, 26 to define a space between the end face of the pipe segments 24, 26 and the shoulder 314′. Alternatively, the end faces of the pipe segments can engage the shoulder 314′ to further limit axial travel of the pipe segments 24, 26 through the fitting 300′.
The fitting 300′ further includes one or more channels 318′ to define a leak path for fluid conveyed through the joint assembly. More specifically, the fitting 300′ preferably includes a channel 318′ to define a leak path over the outer surfaces of the pipe segments 24, 26 through which a gas or liquid contained in the pipe segments 24, 26 can escape to atmosphere. The channel 318′ can form a discontinuity in the interference fit between the inner surface 313′ and the outer surface pipe segments 24, 26 so as to be in communication with the central passageway 315′. Accordingly, the channel 318′ is in communication with sockets 312a′, 312b′ such that fluid flowing from the ends of the pipe segments 24a, 24b into the central passageway 315′ of the fitting 300′ can escape to atmosphere. As with the previously described fitting 300, the fitting 300′ forms a fluid tight joint assembly using a preferably flowable sealant material as discussed above.
The inner surface 313′ preferably tapers narrowly from the end face 310a′ of the fitting 300′ to the shoulder 314′ to define a socket length L′ preferably about 1.19 inches. The taper of the inner surface 313′ further preferably defines a first diameter D1′ at the entrance of the socket 312a′ of about 1.325 inches and a second diameter D2′ at the base or bottom at the socket 312a′ proximate the shoulder 314′ of about 1.310 inches. Accordingly, the second diameter D2′ is preferably smaller than the first diameter D1′. The shoulder 314′ located along the inner surface 313′ preferably extends radially inward toward the central axis A′-A′ by an amount so as to present a surface to inhibit the axial migration of a pipe segment toward the center of the fitting yet sufficiently low in profile so as to provide a desired fluid flow therethrough at a desired pressure and/or fluid velocity. Preferably, the shoulder 314′ defines an internal diameter D3′ of the fitting 300′ to be about ninety-four percent of the first diameter D1′ or about 1.25 inches and is more preferably about 1.10 inches in diameter. Either of the surfaces of the shoulder extending perpendicularly to the central axis A′-A′ can be countersunk such that the shoulder 314 defines another internal diameter D4′ of the fitting 300 preferably measuring about 1.11 inches. The counterbore of the surface is preferably to a depth of about 0.035 inches.
As seen in
The sidewalls 320′ of the channel 318′ are spaced apart to define a channel width W′ preferably measuring about 0.045 inches and more preferably about 0.060 inches. The inner surface 313′ and the sidewalls 320′ further define the depth or height H′ of the channel 318′. Preferably, the maximum height of the channel 318′ in the region of the socket 312a′, 312b′ is about 0.010 inches and more preferably about 0.025 inches, and the channel volume is preferably defined by the channel length L′, the channel width W′ and depth H′. The channel 318′ can follow the schedule of dimensions, depth H′ and width W′, measured at the end face 310′, as provided in Table 1a for a range of nominal size fittings. Although the channel height H′ and the width W′ can remain constant over a range of nominal fitting sizes, the channel length L′, the channel width W′ and/of the channel height H′ can vary with the fitting size to preserve a constant dimensional relationship. Where for example, the dimensions of the preferred channel 318′ in the preferred nominal one inch fitting 300′ define a height-to-length ratio H′:L′ of about 0.008, the channel length L′ and height H′ can be dimensioned accordingly for a fitting of lesser or greater nominal size to preserve the preferred ratio. More preferably, the channel 318′ is dimensioned such that the channel or leak path can define a void, in conjunction with the outer surface of an inserted pipe segment, through which fluid can readily leak and provide a visual indicator of an improper seal, and further form an adequate fluid=tight sealed connection upon application of an appropriate amount of sealant material.
The total channel volume of the fitting 300′ can be further defined by the number of channels 318′ radially disposed about a socket 312a′, 312b′. Although only a single channel 318′ is shown at the end face 310b′ in
The fitting 300′ is preferably a Schedule 40 CPVC nominal one inch coupling.
The interior surface 313′ and the outer surface 311′ preferably define a constant, minimum, wall thickness preferably measuring about 0.14 inches. Accordingly in the region of the channel 318′, the outer surface 311′ of the fitting 300 forms a projection 319′ preferably having a width W″ and a height H″ and axial length to define a volume to provide the constant or minimum wall thickness. The constant wall thickness of the fitting is preferably configured such that the fitting, when appropriately tested, can satisfy and/or exceed requisite industry standards such as, for example, ASTM Specification F438-02.
The preferred couplers described herein throughout are appropriately Schedule-40 or Schedule-80 constructed from CPVC material such as, for example, the CPVC material described in the Lubrizol Corp. Product Data Sheets: (i) TempRite® 3205 (2003) or (ii) TempRite® 3205 (2003) which are incorporated by reference in its entirety, or alternatively Poly Vinyl Chloride (PVC) material. The preferred method of forming the fittings 300 is by general injection molding using a injection molding process such as, for example, generally described in Noveon Inc. publication entitled, “TempRite® CPVC Material Solutions: General Injection Molding Guide” (January 2003), which is incorporated by reference in its entirety. Preferably, the injection process includes using a mold that defines the inner surface 313 and the axially extending central passageway of the preferred fitting 300. The cavity surface of the mold forming the inner surface 313 further includes axially extending ridges or projections to define one or more channels 318 described above. Preferably, the fittings 300 are further constructed in accordance with applicable ASTM standards including F438-02 defining SDR (Standard Dimension Ratio) 13.5 dimensions, so as to define a preferred ratio of outside diameter to wall thickness of the fitting, ASTM F 439, or ASTM F 1970. Accordingly, the channel 318 is cut so as to preferably define a channel height H to wall thickness ratio of about ⅓.
Alternatively, the preferred fittings or end fittings can be constructed from either one of copper or steel material and/or used in combination copper or steel pipe segments to form a chemically sealed or soldered piping assembly. A preferred copper-to-steel (CTS) fitting and/or assembly can be configured for a range of nominal pipe diameters, preferably ranging from about ¼ inch to about 24 inches. Although the preferred fittings and assemblies described herein are well suited for fire protection applications, it should be understood that the preferred couplers can be used in alternative mechanical/plumbing or piping residential, commercial or industrial applications. Alternatively to forming the preferred channels described herein by way of injection molding or extrusion, the channels can be formed at the time of installation of post-fabrication of a CPVC plastic fitting or piping element. Specifically, a channel can be hand or machine cut along an applicable surface of the fitting or pipe segment sufficiently deep to form the desired channel, yet shallow enough to avoid unnecessary pooling of the sealant material.
As noted above, the channel 318 may be alternatively configured so long as it provides the coupler in a joint assembly 100 with a fluid path to indicate an improper seal to operating personnel.
Another illustrative coupling 300a″ is shown in
In any one of the preferred fittings 300 described herein, the fluid discharged from the channels 318 is preferably discharged to atmosphere from a channel opening at the end faces 310a, 310b of the fitting 300. Alternatively or in addition to, the channel 318 can include or be configured as a through hole 324 along a medial portion of its outer surface 311 between the end faces 310a, 310b. For example, in another alternative embodiment illustrated in
Referring to the embodiments illustrated in
In the illustrative embodiment of a preferred fitting 300c″ in
In the alternate embodiment of the fitting 300d″ of
Shown in
Shown in
The socket 212 and the inner surface 213 are preferably configured to form an interference fit at one or more circumferential points with the outer surface of the second pipe segment 26. For example, the socket 212 is further defined by the preferably tapering inner surface 213 so as to form a substantially circumferential interference fit 216 about the second pipe segment 26. The taper of inner surface 213 can define an angled surface that limits axial progression of a pipe segment 26 to define a space between the end face of the pipe segment 26 and the shoulder 214. Alternatively, the end face of the second pipe segment 26 can engage the shoulder 214 to further limit axial travel of the second pipe segment 26 through the end fitting 210.
As in the case of the preferred fittings 300 described above, the end fitting 200 of pipe segment 24′ further includes one or more slots or channels to define a leak path through which fluid can be conveyed in the absence of an appropriate amount of sealant material. More specifically, the pipe end fitting 200 preferably includes at least one channel 218 to define a leak path over the outer surfaces of the second pipe segment 26 through which a gas or liquid contained in the pipe segments 24′, 26 can escape to atmosphere. The channel 218 can form a discontinuity in the interference fit 216 between the inner surface 213 and the second pipe segments 26. The channel 218 is further in communication with the socket 212 such that fluid flowing from the pipe segments 24′, 26 into the end fitting 210 can escape to atmosphere in the absence of a fluid tight seal. To form the joint 100′ as a fluid tight assembly for service in the piping system 10, a preferably flowable sealant material (not shown), as described above, is applied to the outer surface of the second pipe segment 26 and along the inner surface 213 of the sockets 212. In the fluid tight assembly, the sealant material fills the channels 218 of the fitting 210 so as to prevent the escape of fluid to atmosphere. The channels 218 therefore provides the joint 200 with an indicator to operating personnel of a system 10 an incomplete or failed fluid-tight joint assembly. More specifically, operating personnel using anyone of the previously described detection techniques, is made immediately aware of the lack of adequate or complete absence of sealant material in the socket 212 by the indication of fluid flowing from the channel 218 and/or the failure of the joint 200 to maintain pressure.
Shown in
Shown in particular with respect to the socket 212, the inner surface 213 further preferably defines the depth or height H′ of the channel 218. The channel height H preferably deepens from a minimum at the end face 210 of the fitting 200 to a maximum at the shoulder 214. The channel 218 can alternatively or additionally be characterized by a radial distance R′ preferably measured from the central axis A′-A′ to the interconnecting wall surface 222 and in which the radial distance R′ is preferably constant. Alternatively, the interconnecting surface 222 of the channel 218 can parallel the taper of the inner surface 213 such that the radial distance R′ varies accordingly along the length of the channel. Further in the alternative, the interconnecting surface can define a non-planar profile such as, for example, a wave-form, along its axial length.
A channel volume is preferably defined by the channel length, channel height H′ and the channel width W′. The total channel volume of the fitting 200 can be further defined by the number of channels 218 radially disposed about a socket 212. Although only a single channel 218 is shown at the end face 210 of the fitting 200, a plurality of channels 218 may be radially disposed about the central axis A′-A′ of the end fitting 200 to provide multiple indicators to the operating personnel regarding the adequacy of the seal in the joint 200 as described above. The channel volume is configured sufficiently large enough provide a desired leak path so as to prevent any interference fit between the inner surface 213 and the pipe segment 26′ from holding fluid pressure in the joint 100′. Moreover, the channel volume is sufficiently small so as to avoid undesirable pooling of sealant material in the channel 218 proximate the pipe element disposed within the socket 212.
Preferably, the various dimensions of the channel 218, i.e, its depth H′ and width W′ are constant over a range of nominal pipe sizes. The depth H′ and the width W′ can follow the schedule of height and widths in Table 1a at the end face 210a. Alternatively, the channel dimensions can vary with the size of pipe segment to be inserted therein. Accordingly, the fitting 210 can be configured as a reducer in which the socket 212 has smaller inner diameter D′1, D′2 dimensions as compared to the central passageway diameter of the pipe segment 24′ in order to couple a dissimilarly sized pipe segment. Moreover, the socket 212 can be configured for receipt of an adapter to convert the socket-type connection of the socket 212 to a threaded-type connection. Table 2 provides a preferred schedule of socket and channel dimensions, as described above, for a given nominal pipe segment diameter.
Again, the features of the outer and inner surfaces 211, 213 and channel 218, including the sidewalls 220 and the interconnecting surface 222 of end fitting 200 can be alternatively configured in any manner as described above with respect to the outer and inner surfaces 311, 313, and channel 318, including the sidewalls 320 and interconnecting surface 322 of the fitting 300. Accordingly, the sidewalls 220 are spaced apart to define a channel width W′ and are further preferably substantially vertical. However, the sidewalls 120 can alternatively define an angle with respect to the axis XIVB-XIVB bisecting the channel 218 so as to vary the width W of the channel 218 over the height H. The inner connecting surface 222 is shown as substantially planar, but the surface can be substantially radiused or preferably concave with respect to the interior of the channel 218. Moreover, the corners or bends transitioning surfaces in the channel 218 can be substantially angular as shown or alternatively the corners or bends can be radiused. The channel width W′ can be constant or alternatively vary along the axial length L′, L′1 of the channel 218. In particular, the channel width W′ may taper narrowly from the end face 210a to the shoulder 214. The resultant narrowing channel 218 can create a venturi effect so as to eject any fluid in the channel 218 with some appreciable velocity. Shown in
Each of the preferred joint assemblies described above, preferably include a coupler having a channel configured along the inner surface of a socket to form a leak path, in cooperation with a pipe segment, in order to provide operating personnel with an indication of an improperly sealed joint. It should be understood that the same effective leak path can be provided by forming a channel along the outer surface of a tubular wall member such as for example, a pipe segment for cooperation with the inner surface of a socket of a pipe fitting or end fitting. For example, shown in
The various configurations of the channel described with respect to the preferred fittings 300 and pipe end fitting 200 are above is substantially equally applicable to a channel 418 formed on the outer surface of the pipe segment 424, 426. Accordingly, the channel 418 of the pipe segment can vary in width height and/or depth along its length. For example, the channel 418 can follow the schedule of depth and width dimensions in Table 1a. Moreover, the channel 418 can be substantially axially linear or alternatively progress axially and circumferentially, as shown for example, in the helical channel 418 of
The variable configurations of the channel 418 can be formed and disposed about the outer surface of the pipe segment 26′ for insertion in a socket-type pipe end fitting having a circumferentially and substantially continuous inner surface 213 in order to form the desired leak path.
Exemplary couplers constructed in accordance with the embodiments having a channel as described above, were incorporated into a test pipe assembly for pneumatic and hydraulic performance testing. The preferred hydraulic and pneumatic tests are configured to determine or evaluate one or more the following performance features of a fitting 300: (i) the time to full evacuation of a predetermined pressure of fluid from the test assembly; (ii) time for maintaining a specified pressure; (iii) the number of cycles over which the fitting is cycled between a low and high pressure; and (iv) the burst pressure of the assembly. The results of the tests can be used to evaluate or verify a channel configuration for use in a working coupler.
Shown in
The hydraulic and pneumatic tests include: (i) a pneumatic leak test; (ii) a hydraulic leak test; (iii) a first hydrostatic pressure test; (iv) a second hydrostatic pressure test; (v) a hydraulic burst test; and (vi) a hydraulic cycle test. Under each of the pneumatic and hydraulic leak test, the ends of the test pipe segments 24′, 26′ that are respectively inserted into the sockets of the fitting 300′ are each press fit into the sockets without any application of a sealant so as to form the dry fit in order to evaluate the channel 318 as an indicator of an improperly sealed joint. Under the pneumatic leak test, compressed air is introduced into the test assembly through the input end cap 28′, and the input pressure is increased to 10 psi. The time for the complete evacuation of the compressed air from the channels 318 is recorded. Under the hydraulic leak test, water is introduced into the test assembly through the input end cap 28′, and the input pressure is increased to 10 psi. The time for the complete evacuation of the compressed hydraulic fluid from the channels 318 is recorded.
Subsequently, a sealant material, preferably Blazemaster CPVC Cement TFP-500, is applied to each of the ends of the test pipe segments 24′, 26′ and the inner surface 313 of the sockets of the fitting 300 to deform or reconstitute the channels 318 and completely seal the test assembly for use in the hydraulic static, cycle and burst pressure tests. In the first hydraulic static pressure test, the sealed test assembly is pressurized to the preferred working pressure of the test fitting, about 175 psi and the pressure gauge 31′ is observed to see that the test assembly can hold the test pressure constant for at least five minutes. In the second hydrostatic pressure test, the sealed test assembly is pressurized to about 875 psi, and the pressure gauge 31′ is observed to see that the sealed test assembly can hold the test pressure constant for at least five minutes. In the cycle test, water is controlled in and out of the fluid assembly to cycle the pressure in the assembly preferably between about 0 psi and about 350 psi. The pressure is cycled between the two pressures until the earlier of 3,000 cycles or until failure of the assembly. The water pressure is then increased to determine the burst pressure and location of failure in the test assembly.
The above described tests were conducted for a variety of channel 318 profiles defined by the height H and width W of the channel 318 when measured at the end face 310 of the fitting 300 as shown for example, in
According to the summary tables, for the various configurations of channel, the average pressure at which a pneumatic leak is detected ranged from about 0.5 psig to about 1.7 psig Preferably a leak is detected at 1 psig or less from the channel in the test assembly. Detection of a leak at a pressure of 1 psig or less in the test assembly is believed to translate to early identification of a leak in a full piping system having potentially a large number of joint assemblies and hundreds of feet of pipe run. With regard to the pneumatic evacuation time, it is preferred that the test assembly and more specifically the channel of the coupler evacuate the test pressure of 10 psig in approximately 3.5 seconds or less. It is believed that such a preferred evacuation time will facilitate leak detection in a full piping system particularly where the method of detecting a leak employs a single pressure gauge. Fluid pressure which readily leaks from a channel formed in a coupler can translate to a dramatic response at the pressure gauge which can be more easily identified by operating personnel as a leak requiring a sealing repair.
Tables 3b summarize the results of the hydraulic testing. The table shows the time required to exhaust 10 psi from the assembly.
With regard to the pneumatic evacuation time, it is preferred that the test assembly and more specifically the channel of the coupler evacuate the test pressure of 10 psig in under 10 seconds. It is believed that such a preferred evacuation time will facilitate leak detection in a full piping system particularly where the method of hydraulic leak detection employs a single pressure gauge. Fluid pressure which readily leaks from a channel formed in the coupler can translate to a dramatic response at the pressure gauge which can be more easily identified by operating personnel as a leak requiring a sealing repair.
Summarized in Tables 4c and 4d are hydraulic test in which the test assembly was sealed about the coupler using Blazemaster® CPVC TFP-500 Cement. Each of the samples was dynamically tested. More specifically, for each of samples and their given channel configurations, the number of cycles were recorded over which the hydraulic pressure was cycled between zero and three hundred fifty (0-350) PSI. Each of the sealed samples was then subjected to hydraulic testing. Initially, the assembly was pressurized to 175 psi and was observed for five minutes. The assembly was then pressurized to 875 psi and observed for five minutes. In each of the samples, the assembly successfully held the static pressure over the entire test period. The assembly was then pressurized to the point of failure.
Each of the sealed performance test assemblies successfully cycled over the 0-350 psi range on average for 3,000 cycles or more. With regard to the burst and failure point test, each of the assemblies failed on an average from about 1400 psig to about 1500 psig Notably, the assembly splits at the pipe and not the coupler. Accordingly, the sealed performance tests demonstrate that for the channel configurations listed, a coupler having such an included channel can be sealed, performs successfully and does not have reduced performance as compared to coupler without a channel. As a matter of comparison, samples of standard nominal one inch couplings (no channel) were subject to similar sealed performance tests and the standard couplings were shown to have an average cycle count of 3,118 cycles over the 0-350 psi pressure range. The test assemblies using the standard fittings were also shown to have an average burst pressure of about 1480 psig with the assembly splitting at the pipe and not the coupling.
To further demonstrate that the inclusion of a channel in a coupler does not degrade performance, an alternate sealant material was utilized in the test assembly. Three channel configurations were tested in the pneumatic and hydraulic tests described above. For the sealed performance test, the assembly is sealed about the coupler using an epoxy, preferably epoxy product 10-3216 from EPDXIES ETC. . . . located in Cranston, R.I. Results of the test are summarized below in Tables 5a-5b and 6a-6b.
With regard to the burst and failure point test, each of the assemblies failed on an average at about 1500 psig Notably, the assembly splits at the pipe and not the coupler.
To further demonstrate that the preferred coupler can be constructed from alternate materials, a copper test assembly was constructed from a nominal one inch coupling and twelve inch copper pipe. Two channel configurations were tested in the pneumatic and hydraulic tests described above. Results of the tests are summarized below in Tables 7a-7d.
The copper test assemblies were soldered to form a fluid tight seal about the test coupling. In the sealed hydraulic test, the assembly was pressurized to 200 psi and was observed for five minutes. In the sealed hydraulic test, the assembly was pressurized to 1000 psi and observed for five minutes. In each of the samples, the assembly successfully held the static pressure over the entire test period. Each of the samples was further dynamically tested. More specifically, for each of samples and their given channel configurations, the number of cycles were recorded over which the hydraulic pressure was cycled between zero and 400 (0-400) PSI. Results of the cycle test are summarized in Table 8a. Each sample assembly was then pressurized to 3000 psi, and all but one of the samples maintained a fluid tight seal and showed no sign of failure. The one sample that did not pass the 3000 psi test, failed to do so because of a problem with the solder and not due to the presence of a channel in the test fitting.
To demonstrate that a channel of a given configuration can be employed in varying nominal size pipe, a test assembly was constructed from a nominal three inch CPVC coupling and one foot of nominal three inch pipe. Two channel configurations were tested in the pneumatic and hydraulic tests described above. Results of the tests are summarized below in Tables 9a-9d.
According to the test results, at least two channel configuration that were suitable for use in the nominal one inch coupling provided equally satisfactory performance in the nominal three inch couplings. In particular, the sealed performance tests again demonstrate that the channels in the nominal three inch coupling do not reduce the performance of the coupling. Specifically, the average cycles and burst pressures were as expected for a nominal three inch fitting. In the hydrostatic pressure test, all the tested samples held the 175 psi of water pressure for five minutes, and only one of the four test samples failed at the 875 psi hydrostatic test. Notably in the burst pressure tests, the coupling failed along its medial circumference which indicates that the failure was independent of the channels.
To further evaluate the test data and the preferred test assemblies and couplers, a series of fluid dynamic models were developed to compare the test data to a calculated performance. More specifically, each model was constructed to characterize a given coupler and more specifically characterize a fitting having a given channel configuration in a preferred test assembly. The model was then further expanded to evaluate the coupler when installed in a residential occupancy fire protection piping assembly and a commercial occupancy fire protection piping system. Each model characterizes the coupler installed in a preferred piping assembly having a volume that is typical for the given pipe assembly. In each model, the assembly is simulated as being pressurized with an initial pressure, preferably 10 psi of air. With the modeled piping assembly at an initial pressure, the assembly is modeled at an initial time t0=0 sec, having an open orifice that approximates the leak path formed by the channel in the modeled fitting about a pipe segment. The model then simulates the evacuation of fluid, in this case, air from the modeled channel by calculating for each unit of time, the pressure remaining in the piping system.
The model calculates the pressure at each unit of time by solving a set of equations that relate the system pressure to the mass flow rate of the gas exiting through the coupler channel. In a piping assembly having a coupler with a preferred channel, the mass flow rate of the gas through the open channel is determined by
To relate the change in pressure, volume and temperature to the mass flow rate of the gas, the following equation is used:
For a pipe assembly under pressure having a coupler with an open channel forming a leak path, the internal gas pressure change can be characterized by
where Pao and Tao=gas pressure and temperature respectively at the moment of sprinkler opening;
In Eq. 1 and Eq. 2:
where Pao and Tao—are the initial pressure and temperature of the gas in the test assembly. To determine the air pressure in the system as function of time, Equation 4 can be integrated by a standard numerical integration scheme.
The above equations were used to generate the pipe assembly models and solve for the pressure in a modeled system at each interval of time. Based on the equations above, the input variables for the model are: (i) total system volume Va, (ii) the initial system pressure Pao; (iii) the initial temperature of the air in the system Tao; and (iv) the orifice size that corresponds to the channel cross-sectional area. The system volume was based upon an assumed number of linear feet for a given nominal size pipe and an assumed number of correspondingly nominally sized fittings. For a conservative estimate, the calculated system volume Va was increased an additional four percent. For each modeled system, the initial system pressure was set at 10 psi, and the initial gas temperature was assumed to be approximately ambient temperature, sixty-eight degrees Fahrenheit (68° F.). Additional assumptions were made for each model, including the assumption that friction losses through the piping could be ignored and that the leak path formed by the channel is assumed to be free of any obstruction or debris. In addition, it is assumed that at the initial start of evacuation, i.e., time=0 sec., the evacuation immediately begins.
A first model was generated which corresponded to the test assembly for a preferred nominal one inch fitting, as described above. The modeled fitting included a 0.015 in.×0.015 in. channel, and with one foot of nominal one inch pipe, the assembly was determined to have a system volume Va of about 0.228 gallons (gal.). The initial system air pressure Pao was set to 10 psi and the initial system air temperature Tao was assumed to be 68° F. According to the model results, the 10 psi of system pressure was evacuated within five seconds. The model further assumes the leak path in a joint assembly is at a minimum by being defined exclusively through the channel of the modeled fitting. Therefore the model does not account for the additional leak path volume, in addition to the channel, defined by the gaps between the inner surface of the fitting and the outer surface of the pipe in an actual test assembly.
To further demonstrate the accuracy of the model, two sealed fluid-tight test assemblies were constructed with the ends of the pipe assemblies each having an end cap with a 0.063 inch diameter hole drilled into it. The hole presents the exclusive point of discharge in each of the test assemblies. The test assemblies were then subjected to the pneumatic evacuation tests described above. Plots of the pneumatic profiles for the two test assemblies are shown in
The model was expanded to evaluate the evacuation performance of the preferred coupler and channel in a larger piping system. Accordingly, a second model was generated to approximate the preferred coupler in a fire protection system for a small residential occupancy. The second model assumes that the system is constructed using about 225 feet of one inch piping, twenty-five 90-Degree elbows and twenty-five Tees to define a system volume Va, including the four percent increase, of about 11.544 gal. The initial system air pressure Pao was set to 10 psi and the initial system air temperature Tao was assumed to be 68° F. The time dependent pressure profiles were determined for seven different channel configurations in a nominal one inch fitting, which define five different total channel cross-sectional areas measured at the end face of the fitting: (i) 0.0002 sq. in.; (ii) 0.0012 sq. in.; (iii) 0.0015 sq. in.; (iv) 0.0030 sq. in.; (v) 0.0036 sq. in. The various channel configurations area summarized in Table 10 below.
Because the model is dependent upon the total cross-sectional area of a channel opening at the end face of the modeled fitting, various dry fit improper seals are presented by a given pressure evacuation profile. For a single channel scenario, the model characterizes only one socket in the coupling that is improperly sealed. For a two channel scenario, the model characterizes: (i) a single channel extending the length of the coupling with each socket of the coupling improperly sealed; or (ii) two channels of a one socket in the coupling improperly sealed. Accordingly, for a channel having a configuration of 0.015 in. H deep and 0.060 W wide, the 0.0015 in.2 area covers one socket in the coupling improperly sealed and the 0.0030 in.2 area covers two sockets improperly sealed. It should be understood that the listed cross-sectional areas could cover scenarios of channel configurations not listed.
For each of the five total channel cross-sectional areas, the pressure time dependent function was calculated and plotted for the small residential system in
A third model was generated to approximate the preferred coupler in a fire protection system for a medium residential occupancy. The third model assumes that the system is constructed using 450 feet of one inch piping, fifty 90-Degree elbows and fifty Tees to define a system volume Va, including the four percent increase, of about 23.192 gal. The initial system air pressure Pao was set to 10 psi and the initial system air temperature Tao was assumed to be 68° F. The pressure profile for each of the five total channel cross-sectional areas is plotted in
A fourth model was generated to approximate the preferred coupler in a fire protection system for a large residential occupancy. The fourth model assumes that the system is constructed using about 750 feet of one inch piping, seventy 90-Degree elbows and seventy Tees to define a system volume Va, including the four percent increase, of about 38.584 gal. The initial system air pressure Pao was set to 10 psi and the initial system air temperature Tao was assumed to be 68° F. The pressure profile for each of the five total channel cross-sectional areas is plotted in
A fifth model was generated to approximate the preferred coupler in a fire protection system for a commercial occupancy. The fifth model assumes that the system is constructed using about 500 feet of 1½ inch nominal pipe, 750 feet of one inch piping, one hundred 90-Degree elbows and one hundred Tees to define a system volume Va, including the four percent increase, of about 90.168 gal. The initial system air pressure Pao was set to 10 psi and the initial system air temperature Tao was assumed to be 68° F. The pressure profile for each of the five total channel cross-sectional areas is plotted in
The plots characterize how readily a modeled preferred coupler with a channel evacuates a piping system under pressure. For each of the channel cross-sectional areas modeled, evacuation of a measurable amount of air pressure occurred within two minutes. Combining the modeled results with the test assembly data, it is believed that a leak path can be created with a coupler having a channel cross-sectional area, measured at the end face, ranging from as small as about 0.0002 square inches (in.2) to about 0.01 in.2. However, the plots further indicate that the rate of evacuation decreases with increasing system volume, and it is believed that in order for a preferred coupler to provide an effective leak path to detect an improper seal, the rate of change in pressure in a full system must be dramatic enough to be identified by the piping system operating personnel. Thus where, for example, the operating personnel is monitoring a system pressure gauge in the basement of a medium residential occupancy and the improper seal is in the most remote joint assembly of the piping system, the rate of drop in system pressure due to evacuation from the coupler channel must be significant enough so as to register on the system pressure gauge and be noticeable to the operating personnel.
Thus, for any given channel cross-sectional area, the evacuation pressure profile preferably defines a rate of change in pressure that can be registered on the available pressure sensing or monitoring equipment. A preferred pressure gauge is one that is practical for pneumatic pipe system inspection techniques, such as those described above, and is readily available. The gauge is further preferably graduated to read pressure from 0 psig to 30 psig, so as to be able to register a preferred minimum rate of change in pressure of about 0.5 psig per minute within a piping system. One exemplary pneumatic gauge is manufactured by WIKA Instrumentation Corporation of Lawrenceville, Ga., and graduated from 0-30 psig Referring to the pressure plots of
However, the ability of the channel to provide an effective leak path is only one factor in defining an appropriate channel configuration for a coupler. As discussed above, it is preferred to maintain a minimum wall thickness in the coupler in order to comply with one or more industry standards. Accordingly, it is believed that in the absence of an outer surface projection 319 on the coupler, as seen for example in
In view of the above factors, for a single channel formed in the coupler, the channel cross-sectional area can range from about 0.0002 in.2 to about 0.0036 in.2, preferably ranges from about 0.0012 in.2 to about 0.0036 in.2, and more preferably ranges from 0.0015 in.2 to about 0.0036 in.2 The channel depth H can range from about 0.005 inches to about 0.060 inches, and the channel width can range from about 0.015 inches to about 0.1 inches. Preferably, the channel depth H ranges from about 0.025 inches to about 0.060 and is most preferably about 0.025 inches, and the channel width W preferably ranges from about 0.025 inches to about 0.060 and is most preferably about 0.060 inches.
While the present invention has been disclosed with reference to certain embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the present invention. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof.
This is a National Stage application under 35 U.S.C. 371 of International Application No. PCT/US2008/050821, filed Jan. 10, 2008 which claims the benefit of priority to (i) U.S. Provisional Patent Application No. 60/977,010 filed Oct. 2, 2007; (ii) U.S. Provisional Patent Application No. 60/956,655 filed Aug. 17, 2007; (iii) U.S. Provisional Patent Application No. 60/917,459 filed May 11, 2007; and (iv) U.S. Provisional Patent Application No. 60/884,262 filed Jan. 10, 2007, each of which is incorporated by reference in its entirety.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US08/50821 | 1/10/2008 | WO | 00 | 6/21/2012 |
| Number | Date | Country | |
|---|---|---|---|
| 60884262 | Jan 2007 | US | |
| 60917459 | May 2007 | US | |
| 60956655 | Aug 2007 | US | |
| 60977010 | Oct 2007 | US |
