Piping system with transition coupling

Abstract

In a pipeline system having a plurality of pipe segments joining a fluid supply tank to a fluid dispenser, the invention includes a pipe coupling assembly for use on at least one terminal end of a fluid transfer pipe, where the transfer pipe has an inner tubular member for transferring fluid and an outer tubular member and an interstitial space there between. The coupling assembly comprises a transition coupling for attachment to the pipe segment to provide a first path for the fluid in the inner tubular member and a second path for the interstitial space. The coupling assembly further comprises a transition tube assembly for attachment to the transition coupling to provide separate paths for the transfer fluid and the interstitial space, where the interstitial space provides a means for performing leak detection or fitting integrity tests during application of either a vacuum condition or pressurized gas input via such selective access.

Description

FIELD OF THE INVENTION [0001] This invention relates to transition coupling and fitting assemblies for connecting segment of pipes into systems. More particularly, the invention relates to a new system using an assembly for coupling coaxial pipes, such as flexible coaxial pipes, of the type used in environmentally conscious petroleum transfer systems. BACKGROUND OF THE INVENTION [0002] Because vehicle fueling facilities, like retail service stations, are becoming more environmentally conscious, a shift has occurred from the use of rigid underground piping to flexible piping. A primary reason for this shift from rigid to flexible piping is that flexible piping has fewer pipe connections than rigid systems since the flexible system can accommodate virtually any orientation or alignment of the pumps and tanks. With fewer pipe connections, the piping system is considered more environmentally safe. Movement of the underground storage tank due to the shifting underground tanks is also mor...

AI Technical Summary

Benefits of technology

[0026] The invention is a pipe system for distributing fluids from a storage tank to one or more dispensers comprising an originating adaptor fitting located at the tank and shear valves located at each of the one or more dispensers, a pipe segment extending between the adaptor fitting and one of the shear valves, the pipe segment having an interstitial space between an inner and an outer pipe. The invention further comprises a transition coupling connecting the adaptor fitting to the pipe segment, the transition co

Problems solved by technology

Rigid systems require on-site measurements and cutting of each piece, along with the intensive labor involved in making two pipe connections every time the piping undergoes a change in direction.

This system, however, has a number of drawbacks, including the fact that the primary and secondary pipes are installed separately and that fittings are required for each of the two types of pipes.

Moreover, because each of the pipes connects with an access chamber, a rapid and simple method of monitoring the condition of the primary piping may not be possible.

Although the sumps in the '477 patent are capable of being monitored visually by an attendant, but the demand of other tasks to be performed by the attendant eventually leads to fewer and fewer inspections.

Most important is that leaks may occur randomly, not only just prior to a visual inspection, and especially when inspections grow less frequent over time.

In the evolution of piping systems as discussed above, the relationship of the outer, secondary containment pipe to the system has become more complex.

However, every sump had to have a monitoring device since each sump, by design, represented a low point where fluid could collect.

The difficulty in such two pipe systems can easily be seen by viewing FIG. 2 of '477 patent where the outer pipe has a very limited, minor function of simply isolating the primary supply pipe from the ambient environment.

The test boot, however, is not as structurally solid as an access sump, for example, and thus needs to be enclosed in a sump for protection.

First, it is desirable to avoid plastic adhesion or plastic thermally bonded connections, since temperature conditions, chemical exposure, vibrations over time can cause piping joints to fail.

However, in such cases it is necessary to protect the metal from the environment by a coating or isolation to avoid a corrosive and unsafe condition.

Coatings on metal parts, however, often peel off or become damaged during handling of the metal parts.

Also, if the coatings are too thick, the necessary metal to plastic contact to establish an effective seal is not achieved.

This, of course, does not provide a rapid response to a major leak of fluid such as fuel from the primary supply pipe.

Although it is possible to monitor the conditions of one or all of the access chambers, for example by visual inspection, no simple method of monitoring the entire system is possible.

Images