Patent Application
20160069491
The present disclosure generally relates to pipeline constructions, and in particular relates to a self-adjustable piping system installed at a seismic joint for allowing and absorbing movement of pipelines in the piping system.
Modern structures, such as buildings and houses, are built to accommodate thermal expansion and seismic movement of construction elements used for the interior and exterior surfaces including walls, floors, roofs, and the like. For example, adjacent floors move relative to each other, and are spaced apart at a predetermined distance, creating seismic joints or gaps between the floors for clearance. Typically, in an earthquake zone, the seismic joints provide for differential building and building unit movement to occur without risking damage to the entire building structure. The seismic joints may widen or narrow to accommodate the movement of the adjacent spaced structural units.
When pipelines are installed across the seismic joint of the adjacent floors, the pipelines need to be displaceable in accordance with the movement of the corresponding floors or walls. Conventionally, angular, axial and twisting movement of the pipelines at the seismic joint is relieved by a seismic joint system that includes an expansion joint and two gimbaled bellows. For example, the expansion joint is disposed at a center of the seismic joint system to absorb relative movement of connecting pipes, and the gimbaled bellows are connected at opposite ends of the seismic joint system to allow relative angular movement of the connecting pipes.
However, the geometry of the bellows affords only a limited amount of angular movement in a given length for the connecting pipes. To overcome the limited amount of angular movement, a length of hose having a braided outer shell can be used to accommodate the angular movement of the connecting pipes in lieu of the gimbaled bellows. However, a disadvantage of this configuration is that an overall length of the hose required for adequate flexibility becomes too long for the seismic joint system to be used in a confined area.
Such conventional seismic joint systems do not provide a simple method of allowing and absorbing seismic movement of the connecting pipes. Therefore, there is a need for developing an improved seismic joint system having a short overall length and accommodating free angular movement of the connecting pipes such that the joint system can be used in a confined limited space of the building structure.
The above-identified need is met by the present seismic joint system, in which free angular and seismic movement of pipelines are provided. A related advantage of the present seismic joint system is that the present joint system can be used in the confined area of the building structure. A pipe connector having an inner flexible fluid carrier and an outer braided shell or tube is provided for connecting two separate pipes on opposite ends of the connector. To provide radial and longitudinal expansion stability to the inner fluid carrier, the outer braided shell is slidably fitted over an outer surface of the inner fluid carrier along an entire length of the inner fluid carrier. Further, the outer braided shell is reinforced with a specific braiding having a predetermined braiding angle such that the braiding angle provides both lateral and angular movement of the pipes attached to the connector.
More specifically, the present outer braided shell has beneficial structural features. The braided shell has a plurality of threads or strands braided or knitted together in such a way that the threads helically wrap around the hose in groups with alternating directions and provide appropriate mechanical protection over the inner fluid carrier. An important aspect of the present outer braided shell is that each thread makes at least one complete revolution around the inner fluid carrier at a larger helix angle as measured from the longitudinal axis of the shell than conventional braided hose. In a preferred embodiment, an optimal number of revolution is one (1), but a multiple of one revolution (i.e., more than or equal to 2) is contemplated to suit different applications.
This configuration allows for a shorter length of braided hose than a conventional braided hose, while still providing a full revolution of the threads of the braid, therefore, it also allows a sufficient flexibility in a shorter overall length of the shell so that the present joint system can be installed in confined limited spaces of the building structure. More specifically, the present joint system having a gimbal assembly provides a smooth, consistent bend in such a constricted area to help improve the flow of material in the hose and allow the hose to bend readily with a shorter bend radius than the conventional hose during angular movement. Further, due to the configuration of the present outer braided shell, less force is required to bend the present braided hose without causing a braid lock. As a result, the present joint system can be installed inline between existing pipelines in a pipe run without consuming or requiring extra space for the joint system.
Another important advantage is that despite the shorter overall length of the shell, the present outer braided shell provides sufficient lateral and angular movement of the pipelines connected to the seismic joint system. In contrast, a conventional braided shell in a similarly shortened length tends to demonstrate an increasing stiffness on the braided tube when the pipes are connected to the braided tube in a confined space, and affords insufficient lateral and angular movement for the seismic joint system. It is known in the art that an inner peripheral length of the bent braided hose is determined based on a bend radius, a deflection angle, and an outer diameter of the hose.
For example only, the inner peripheral length L can be defined as provided by a formula below.
L=πRø/180+2(s)
where R denotes the bend radius, ø denotes the deflection angle, and s denotes the outer diameter of the hose. When the hose is bent, an outer portion of the hose expands and an inner portion of the hose contracts to compensate the angular motion created by the deflection angle relative to two outer ends of the hose. The conventional braided shell often fails to equalize the angular motion of the hose, and tends to bind up or buckle due to the braiding of the threads. However, braiding the threads at a greater angle from the axis overcomes this problem and restriction set by the formula above. As described in greater detail below, these advantages are achieved by the present seismic joint system.
The foregoing and other aspects and features of the disclosure will become apparent to those of reasonable skill in the art from the following detailed description, as considered in conjunction with the accompanying drawings.
Referring now to
More specifically, the first inner pipe 14 is slidably connected to a first end 18 of the center member 12, and the second inner pipe 16 is also slidably connected to a second opposite end 20 of the center member. More specifically, corresponding ends of the first and second inner pipes 14, 16 are inserted into the center member 12, and slidingly reciprocate and twist within the center member along the longitudinal axis of the center member relative to one another so that the axial and relative rotational movement of the first and second inner pipes are compensated during seismic movement of the pipelines connected to the joint system 10. In a preferred embodiment, the twisting movement of the joint system 10 refers to rotational movements of the pipelines about the longitudinal axis of the center member 12, similar to a torque force, where the entire joint system 10 is rotating together as a single unit.
A first gimbal assembly, generally designated 22, is attached at one end to the first inner pipe 14, and at an opposite end to a first outer tube or pipe 24. Symmetrically, a second gimbal assembly, generally designated 26, is attached at one end to the second inner pipe 16, and at an opposite end to a second outer tube or pipe 28. It is preferred that each gimbal assembly 22, 26 respectively includes a pair of inner arms 30, 30′, a pair of outer arms 32, 32′, and a gimbal ring 34, 34′ having a pair of inner arm pivot pins 36, 36′ and a pair of outer arm pivot pins 38, 38′.
It is contemplated that a mechanical connection between the first gimbal assembly 22 and the first inner pipe 14 is achieved by the pair of inner arms 30, each inner arm of which is attached at one end to the first inner pipe 14, and at an opposite end, is attached to the gimbal ring 34 to pivot about the inner arm pivot pin 36. In a preferred embodiment, the inner arm pivot points 36 of the corresponding inner arms 30 are disposed on opposite sides of the gimbal ring 34, but other suitable configurations are also contemplated.
Each of the outer arms 32 is attached at one end to the first outer pipe 24, and at an opposite end, is attached to the gimbal ring 34 to pivot about the outer arm pivot point 38. As is the case with the inner arm pivot points 36, the outer arm pivot points 38 are also disposed on opposite sides of the gimbal ring 34, but other suitable configurations are also contemplated.
In a preferred embodiment, an opposite side of the center member 12 is similarly constructed and arranged. For example, each of the inner arms 30′ in the second gimbal assembly 26 is attached at one end to the second inner pipe 16, and at an opposite end, is attached to the gimbal ring 34′ to pivot about the inner arm pivot point 36′ in the second gimbal assembly. It is contemplated that the inner arm pivot points 36′ of the corresponding inner arms 30′ are disposed on opposite sides of the gimbal ring 34′.
Similarly, each of the outer arms 32′ in the second gimbal assembly 26 is attached at one end to the second outer pipe 28, and at an opposite end, is attached to the gimbal ring 34′ to pivot about the outer arm pivot point 38′. As is the case with the inner arm pivot points 36′, the outer arm pivot points 38′ are also disposed on opposite sides of the gimbal ring 34′.
An important aspect of the present seismic joint system 10 is that at least one flexible pipe (or hose) connector or assembly 40 is selectively provided for allowing and absorbing angular and lateral movement of the first and/or second inner pipes 14, 16 and the first and/or second outer pipes 24, 28 according to an installation site of the pipe connector. In a preferred embodiment, the lateral movement refers to horizontal movements of the pipelines attached to the present seismic joint system 10. In any configuration, components of the present seismic joint system 10 are connected in fluid communication with one another for providing a passageway for a delivery of a liquid or similar substance.
Referring now to FIGS. 1 and 2A-2B,
Specifically, if the pipe connector 40 is installed in the first gimbal assembly 22, the pipe connector is disposed inside of the gimbal ring 34 of the first gimbal assembly, and is connected to at one end to the first inner pipe 14 and at an opposite end to the first outer pipe 24, thereby being sandwiched between the first inner and outer pipes. On the other hand, if the pipe connector 40 is installed in the second gimbal assembly 26, the pipe connector is disposed inside of the gimbal ring 34′ of the second gimbal assembly, and is connected at one end to the second inner pipe 16 and at an opposite end to the second outer pipe 28, being sandwiched between the second inner and outer pipes.
Referring now to
To provide radial and longitudinal expansion stability to the inner fluid carrier 42, the outer braided shell 44 is slidably fitted over an outer surface of the inner fluid carrier along an entire length of the inner fluid carrier. More specifically, based on an internal pressure generated by a fluid substance traveling within the inner fluid carrier 42, the inner fluid carrier preferably made of a flexible material may expand radially and/or longitudinally to accommodate an increased pressure of the fluid substance. Thus, the outer braided shell 44 helps to maintain and protect a structural integrity of the inner fluid carrier 42 so that the internal pressure does not cause the carrier to swell outwardly and burst or to axially distend.
Another important aspect of the present seismic joint system 10 is that the outer braided shell 44 is reinforced with a specific braiding formed of individual wires or threads, or groups of individual wires or threads, helically arranged on the inner fluid carrier 42 and having a predetermined braiding angle α relative to a longitudinal axis L of the pipe connector 40 such that the braiding angle α allows for both lateral and angular movement of the second inner and outer pipes 16, 28 attached to the connector. A detailed description of the braiding angle α is provided below in paragraphs discussing
In a preferred embodiment, the outer braided shell 44 has beneficial structural features. The braided shell 44 has a plurality of threads or strands, or groups of threads or strands 46, which may be made of metal wires, braided or knitted together in such a way that the threads provide appropriate mechanical protection over the inner fluid carrier. It is contemplated that a length LTH of each thread or groups of threads 46 is sufficiently long so as to helically wrap around the inner fluid carrier 42 a multiple of one complete revolution 48)(360°) around the inner fluid carrier 42. In
For example, the braided shell 44 including the thread 46 having the length LTH of two revolutions (i.e., 720°) is also contemplated. Another example includes the thread 46 having the length LTH of greater than zero but less than two revolutions, for example, the length LTH may be approximately 360° and thus may vary from 360° by no more than 60°, namely, from 300° to 420°, and preferably by no more than 30°, namely, from 330° to 390°. Other fractional combinations of revolutions are contemplated to suit different applications. As discussed above, this configuration allows for sufficient flexibility so that the joint system 10 can be installed in confined limited spaces of the building structure.
For example only, the length LTH of each thread 46 can be defined as provided by expression 1.
LTH=√{square root over ((πND)2+L2)} (1)
where N denotes the number of complete 360° rotation(s) of the thread, D denotes the diameter of the helix of wires around the inner fluid carrier 42 and L denotes the axial length of a single complete rotation of the helix.
Referring now to
In a preferred embodiment, the pipe connector 40 has a pair of circular bands 54 at opposite ends of the pipe connector for securing the inner fluid carrier 42 and the outer braided shell 44 either to the first inner and outer pipes 14, 24 or to the second inner and outer pipes 16, 28 based on an installation site of the connector in the seismic joint system 10. Although a flat-surfaced ring-type band is shown in
As best shown in the
This braiding angle α is determined based on a diameter D of the pipe connector 40 and the number of revolution(s) around the inner fluid carrier 42. In a preferred embodiment, the diameter D ranges between 2 and 8 inches, but other suitable ranges are also contemplated to suit different applications. Thus, for example only, the braiding angle α can be defined as provided by expression 2.
Angle α=arctan(2πr/L) (2)
In this expression, r is the radius of the helix of wires around the inner fluid carrier 42 and L is the length of a complete revolution of the helix.
This angle α configuration of the present seismic joint system 10 being greater than a standard braided hose provides a shorter longitudinal length of the outer shell 44 than the conventional braided hose. As a result, the central member 12 compensates axial and twisting movements of the corresponding inner and outer pipes 14, 16, 24, 28, and similarly, the gimbal assemblies 22, 26 compensate pivotal or flexing movements of the corresponding inner and outer pipes relative to the longitudinal axis L of the pipe connector 40.
Although the drawings, such as
While preferred embodiments of the disclosure have been herein illustrated and described, it is to be appreciated that certain changes, rearrangements and modifications may be made therein without departing from the scope of the disclosure and as set forth in the following claims.
