1. Field of the Invention
The present invention generally relates to a fluid-tight joint for connecting a pair of fluid conveying members together. More specifically, the present invention relates to a fluid-tight modular joint, which is flexible in that it permits axial movement between a pair of fluid conveying members.
2. Background Information
In high pressure and/or high temperature fluid applications, piping or ducting systems are generally designed to provide some degree of flexibility to allow for dimensional tolerances, thermal expansion and contraction, and vibrational deflections between various components which are connected by the piping. Thus, these piping or ducting systems often use flexible joints in the pipe to accommodate dimensional tolerances, thermal expansion and contraction, and vibrational deflections between various components. These types of flexible joints are often used in aircraft applications, power generation and other industrial applications requiring piping systems such flexibility. Examples of such prior flexible joints or couplings are disclosed in the following: U.S. Pat. Nos. 4,054,306 to Sadoff, Jr. et al; 4,071,268 to Halling et al; 4,071,269 to Hailing et al; 4,448,449 to Halling et al; and 4,553,775 to Halling.
Flexible joints must be sealed to prevent leakage even when flexing. To achieve sealing various seal types have been used including sliding seals like packing, TUBESEALS, piston rings, or flexible elements like bellows. Sliding seals can seal over a large range of motion but are able to endure only a limited number of displacement wear cycles. Flexible seals can seal over a limited range of motion but, when displacement is small, they can endure a large numbers of displacement cycles.
In most flex joint applications, the joint must be capable of displacing a large distance just a few times such as when they are being installed or removed for maintenance. In such instances sliding seals are a good solution. In service, the joints must displace again to accommodate the relatively slow but potentially large displacements resulting from thermal expansion, and again the sliding seal can be a good solution for these conditions. However, in applications where there is a significant amount of vibration, a sliding seal wears out quickly due to the very large number of relatively small displacements. In these applications, a flexible seal can be added to a joint that uses a sliding seal, and thus accommodate vibration while retaining all the benefits of the sliding seal.
In view of the above, there exists a need for flexible slide joint which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
One object of the present invention is to provide a flexible slide joint which is has an axially compressible element for small linear displacement and a sliding sealing member configured and arranged to accommodate larger linear movements between first and second tube members.
Another object of the present invention is to provide a flexible slide joint which is capable of enduring a very large number of small amplitude displacements.
Another object of the present invention is to provide a flexible slide joint which is light, compact and can be utilized in environments of extreme temperature.
Another object of the present invention is to provide a flexible slide joint that is easy to manufacture and install.
Another object of some embodiments of the present invention is to provide a flexible slide joint, which provides for angular misalignment between two tubes utilized in a piping system.
The foregoing objects are attained by providing a flexible slide joint that accommodates axial misalignments of a pair of fluid conveying members. The flexible slide joint basically has a first tube member, a second tube member, a sliding sealing member and an axially compressible element. The first tube member has a first center axis. The second tube member has a second center axis. The sliding sealing member is configured and arranged between the first and second tube members to accommodate axial movement between the first and second tube members upon a first predetermined axial force occurring between the first and second tube members. The axially compressible element is configured and arranged between the first and second tube members to accommodate axial movement between the first and second tube members upon a second predetermined axial force occurring between the first and second tube members. The axially compressible element is force balanced relative to the sliding sealing member such that the second predetermined axial force is smaller than the first predetermined axial force.
These and other objects, features, aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention.