Patent Description:
In the construction of buildings and other structures, it is known to use expansion loops that include a flexible portion to allow for movement of the conduit. The movement can be intentional, for example, based upon thermal changes, or misalignment in a piping system, or unintentional, such as from a natural disaster, like an earthquake. Additionally, the movement can dampen vibration of the conduits and reduce the transmission of noise through the conduit. Such an expansion loop is disclosed, for example, in <CIT>.

Many buildings contain refrigeration systems that utilize conduits for transporting fluids. The conduits, or pipes, that are utilized in such refrigeration systems are typically copper. Additionally, these fluids are usually pressurized, therefore requiring any conduits to be rated for such a highly pressurized system, i.e., rated for at least <NUM> or at least <NUM> psi. However, flexible copper conduits are not rated high enough for such systems.

Additionally, conventional expansion loops are made of stainless steel and not suited for connecting to copper conduits. As would be appreciated, the connection between different metals can be problematic as one metal can corrode the other metal overtime. Moreover, the connection between dissimilar metals is usually a weak point for the piping system. While, such a weak point is undesirable in most piping systems, it would be especially undesirable in a highly pressurized system like a refrigeration piping system.

Thus, it would be desirable to provide for a flexible conduit that is suited for the pressurized fluids of refrigeration systems and that can easily be installed within the copper conduits of such systems.

<CIT> discloses a flexible pipe loop for absorbing or compensating for movement in a pipe run, and for reducing stresses in the pipe run. The loop comprises a pair of pipe run elbows, a pair of flexible tube members, a pair of loop elbows, and a third rigid tube member.

<CIT> discloses a thermal expansion compensating device having a conduit with a first opening and a second opening for connection to a first pipe and a second pipe of a hot water system, respectively, the first and second pipes being formed by removing a section from a length of pipe of the hot water system. A pre-tensioning force is applied to the device to axially displace the first opening from the second opening until after connection of the openings of the pipes.

<CIT> discloses a refrigerant pipe that constitutes a refrigerant circuit of a refrigeration apparatus includes: a first pipe; and a second pipe. The first pipe includes a pipe body made of stainless steel; and a connection pipe, made of a material different from stainless steel, disposed at an end of the pipe body in a pipe axial direction.

A new flexible conduit that is suited for connection to copper pipes and is rated to handle the pressure requirements of a refrigeration system has been invented. According to the present invention, an expnasion loop and a method of installing an expansion loop into a piping system are set forth in the independent claims.

According to a first aspect of the present invention, which is defined in claim <NUM>, the present invention may be broadly characterized as providing an expansion loop for a piping system, having a first flexible conduit with a first end and a second end, a second flexible conduit with a first end and a second end, a first rigid conduit connected between the first ends of the first and second flexible conduits, a second rigid conduit connected to a second end of the first flexible conduit and including a conversion conduit and a copper conduit, the second rigid conduit being stainless steel, and, a third rigid conduit connected to a second end of the first flexible conduit and including a conversion conduit and a copper conduit, the third rigid conduit being stainless steel. The first and second flexible conduits are rated for <NUM> psi applications.

The second and third rigid conduits may include elbow portions.

The first and second flexible conduits may be stainless steel. The first and second flexible conduits may also include braided hoses.

The first rigid conduit may be stainless steel.

The first rigid conduit may include two elbow portions.

The first rigid conduit may include a bracket configured to couple the expansion loop to a support structure.

In a second aspect of the present invention, which is defined in claim <NUM>, the present invention may be broadly characterized as providing a method of installing an expansion loop into a piping system, in which the expansion loop has at least two rigid conduits and a flexible portion between the two rigid conduits, wherein the flexible portion has a neutral orientation in which two flexible conduits forming the flexible portion are not bent. The method includes attaching one of the at least two rigid conduits to a first pipe of the piping system, attaching the other of the at least two rigid conduits to a second pipe of the piping system such that the two flexible conduits of the flexible portion are not in the neutral orientation and are in a compressed or extended orientation, and after the at least two rigid conduits have been attached to the first and second pipes, flowing a fluid from one of the first and second pipes of the piping system, through the expansion loop, and to the other of the first and second pipes of the piping system so that the flexible portion returns to the neutral orientation as a result of a temperature of the fluid.

The two flexible conduits of the flexible portion may be in an extended orientation. The fluid may be a hot fluid.

The two flexible conduits of the flexible portion may be in a compressed orientation. The fluid may be a cold fluid.

A third rigid conduit connects the at least two flexible conduits. The third rigid conduit, the at least two rigid conduits, and the two flexible conduits comprise stainless steel. The at least two rigid conduits each further include a conversion conduit and a copper conduit.

The method may include anchoring the expansion loop to a support structure.

These and other aspects and embodiments of the present invention, which may be combined with each other in any manner, will be appreciated by those of ordinary skill in the art based upon the following description of the drawings and detailed description of the preferred embodiments.

The attached figures in the drawings will make it possible to understand how the invention can be produced. In these figures, similar reference numbers denote similar elements.

A new expansion loop for use in a refrigeration piping system has been invented. Surprisingly, it has been found that using rigid connectors having a copper pipe connected to a stainless-steel portion, via a conversion conduit, does not reduce the ability for the expansion loop to operate effectively and efficiently in refrigeration systems. Thus, the expansion loop allows for the stainless-steel flexible conduits, which have a higher-pressure rating, to be used to a copper piping system. Additionally, when installing such an expansion loop, depending on the temperature of the fluid flowing therethrough, the flexible conduits are preferably either in a compressed or an extended orientation in which the flexible conduits are bent. Once installed and fluid flows through the expansion loop, and as a result of thermal expansion or contraction, the flexible conduits return to a neutral orientation in which the flexible conduits are not bent.

Accordingly, with reference the attached drawings, one or more embodiments of the present invention will now be described with the understanding that the described embodiments are merely preferred and are not intended to be limiting.

As shown in <FIG>, the present invention provides an expansion loop <NUM> for a piping system and particularly a piping system having copper pipes <NUM>, <NUM>. The expansion loop <NUM> has a flexible section <NUM>, which in the preferred embodiment includes two flexible conduits 20a, 20b.

Each flexible conduit 20a, 20b includes a first end 22a, 22b and a second end 24a, 24b. As shown in <FIG>, in the depicted embodiment, the two flexible conduits 20a, 20b are not bent or under bending stresses and longitudinal axes (extending from the first ends 22a, 22b to the second ends 24a, 24b) of the two flexible conduits 20a, 20b are generally parallel. Thus, a "neutral" orientation is when the flexible conduits 20a, 20b are not under any bending stresses or moments. Accordingly, in the depicted embodiment, in the neutral orientation, a distance between the first ends 22a, 22b of the flexible conduits 20a, 20b is generally the same as a distance between the second end 24a, 24b of the flexible conduits 20a, 20b.

Each of the flexible conduits 20a, 20b may be an inner corrugated hose with an outer braided cover in which one or both formed of stainless steel. In a preferred embodiment, the flexible conduits 20a, 20b include stainless steel braided hoses with a braid of a double layer of Type <NUM> stainless Steel. Additionally, it is preferred that the flexible conduits 20a, 20b include a corrugated metal hose with a corrugated hose of Type <NUM> stainless steel. The flexible conduits 20a, 20b are rated for applications of at least <NUM> psi and preferably at least <NUM> psi.

A first rigid conduit <NUM> is connected between the first ends 22a, 22b of the flexible conduits 20a, 20b. The terms "first," "second," "third," etc. are used merely for clarity and are not intended to define any number of elements or specifically name any particular elements or features of the present expansion loop <NUM>.

The first rigid conduit <NUM> may be formed of stainless steel. The first rigid conduit <NUM> includes two elbow portions 28a, 28b separated by a linear, or straight, portion <NUM>. The depicted elbow portions 28a, 28b are each <NUM>-degree bends. This is merely preferred. Finally, the first rigid conduit <NUM> may include a bracket <NUM> which allows the expansion loop <NUM> to be supported by a support structure like a wall or a beam.

The second ends 24a, 24b of the flexible conduits 20a, 20b are each connected to, respectively, to second and third rigid conduits 34a, 34b. Both of the second and third rigid conduits 34a, 34b include a copper conduit 38a, 38b. The copper conduits 38a, 38b may be straight, or unbent, conduits.

The second and third rigid conduits 34a, 34b also include elbow portions 40a, 40b that are formed of stainless steel, preferably Schedule <NUM> Type <NUM> stainless steel. The depicted elbow portions 40a, 40b are each <NUM>-degree bends. Again, this is merely preferred, and other angles or ranges may be used, for example, elbow portions 40a, 40b may each have <NUM>-degree bends.

Each elbow portion 40a, 40b is connected to one of the copper conduit 38a, 38b by a conversion conduit 36a, 36b. A silver brazing material is applied to connect the copper metal components to the stainless-steel components. The silver brazing material will provide a sufficient connection and is able to accommodate the different expansion coefficients for the different metals.

As noted above, it has surprisingly been found that such an expansion loop <NUM> is able to safely operate in a high-pressure refrigeration system even with the use of two different metal materials.

Specifically, the expansion loop <NUM> may be installed into a piping system by attaching the second rigid conduit 34a to one of the two pipes <NUM>, <NUM> and then attaching the third rigid conduit 34b to the other of the two pipes <NUM>, <NUM>. In attaching the third rigid conduit 34b, the axes of the two flexible conduits 20a, 20b of the flexible section <NUM> are not parallel. Thus, the distances between, on one hand, the first ends 22a, 22b and, on the other hand, the second ends 24a, 24b are not the same and differ by at least <NUM>%.

For example, as shown in <FIG>, the flexible conduits 20a, 20b may be installed in an extended orientation. In the extended orientation of the depicted embodiment, the longitudinal axes of the flexible conduits 20a, 20b are angled so as to intersect proximate the first ends 22a, 22b of the two flexible conduits 20a, 20b (relative to the second ends 24a, 24b). In other words, the first ends 22a, 22b are closer together compared to the second ends 24a, 24b. The extended orientation is believed to be most suitable when the piping system is for a hot fluid ("hot" meaning having a temperature that is greater than the ambient temperature).

Alternatively, as shown in <FIG>, the flexible conduits 20a, 20b may be installed in a compressed orientation. In the compressed orientation of the depicted embodiment, the longitudinal axes of the flexible conduits 20a, 20b are angled so as to intersect proximate the second ends 24a, 24b of the two flexible conduits 20a, 20b (relative to the first ends 22a, 22b). In other words, the second ends 24a, 24b are closer together compared to the first ends 22a, 22b. The compressed orientation is believed to be most suitable when the piping system is for a cold fluid ("cold" meaning having a temperature that is lower than the ambient temperature).

Once the expansion loop <NUM> is installed in either the compressed orientation (<FIG>) or the extended orientation (<FIG>), a fluid may be allowed to flow through the piping system. For example, the fluid may flow from one of the pipes <NUM>, <NUM>, through the expansion loop <NUM>, and then to the other of the two pipes <NUM>, <NUM>. As a result of the temperature of the fluid now flowing through the expansion loop <NUM>, the flexible section <NUM> transitions to the neutral orientation (<FIG> of the depicted embodiment) in which the longitudinal axes of the flexible conduits 20a, 20b are mostly parallel and/or the distances between the first ends 22a, 22b and the second ends 24a, 24b are generally the same. This method of installation is believed to prolong the life of the expansion loop <NUM> in use.

Claim 1:
An expansion loop (<NUM>) for a piping system, the expansion loop comprising:
a first flexible conduit (20a) having a first end (22a) and a second end (24a);
a second flexible conduit (20b) having a first end (22b) and a second end (24b);
a first rigid conduit (<NUM>) connected between the first ends (22a, 22b) of the first and second flexible conduits (20a, 20b);
a second rigid conduit (34a) connected to the second end (24a) of the first flexible conduit (20a) and including a conversion conduit (36a) and a copper conduit (38a), the second rigid conduit (34a) comprising stainless steel, wherein the conversion conduit (36a) is positioned between the copper conduit (38a) and the portion of the second rigid conduit (34a) comprising stainless steel; and,
a third rigid conduit (34b) connected to the second end (24b) of the second flexible conduit (20b) and including a conversion conduit (36b) and a copper conduit (38b), the third rigid conduit (34b) comprising stainless steel, wherein the conversion conduit (36b) is positioned between the copper conduit (38b) and the portion of the third rigid conduit (34b) comprising stainless steel.