Patent Application
20070246462
1. Field of the Invention
The subject invention relates to a container assembly and, more particularly, to a tank for storing materials under pressure.
2. Description of the Prior Art
Pressure vessels, also known in the prior art as tanks, are commonly used for storing liquid gases at low and high pressure. In the case of tanks containing high pressures, various constructions are employed in order to withstand the associated high operating pressure levels. One construction utilized employs a longitudinal structure around the tank. The structure is commonly referred to as a flange, stringer or weld-flange.
Pressure from the gas and/or liquid is exerted on interior walls of the tank. An excessive amount of pressure can cause the tank to burst. As such, the stringer is constructed to surround the tank and absorb the pressure exerted on the wall of the tank. The typical construction includes a plurality of stringers being joined together at pre-determined assembly joints. The stress exerted on the wall of the tank is absorbed by the stringers and distributed across the stringers and the assembly joints of the stringers.
The assembly joints enable assembly techniques such as fastening, adhesives or welding and are typically flat and possess a small cross sectional area for absorbing the stresses. The small cross sectional area only allows for minimum stress absorption. Although the assembly joints are configured to absorb the stress exerted on the wall of the tank, the assembly joints define a weak point as in the assembly joints tend to be weaker than the geometry they intend to support. When excessive amounts of stress build up at the surface areas of the assembly joints, the assembly joints may deflect and break apart because the small cross sectional area only allows for minimum stress absorption in the presence of multi-axis forces.
The present invention provides a container assembly comprising a tank for storing materials under pressure. A plurality of hoop stringers surround the tank and cross one another at at least one intersection to define joints there between. The invention is distinguished by a portion of the hoop stringers extending radially outward to increase a cross sectional area of the stringers for retaining the pressurized materials in the tank.
Accordingly, the present invention provides a container assembly comprising stringers that distribute stress concentrations at the assembly joints across a larger cross sectional area than that utilized in the prior art. The larger cross sectional area allows for a greater amount of stress absorption. This construction minimizes the possibility of the assembly joints deflecting and breaking apart because larger amounts of stress are distributed among a larger surface area in the presence of multi-axis forces.
Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a container assembly is generally shown in
Referring also to
The hoop stringers 26 include a longitudinal hoop stringer 40 extending about each outer periphery, a radial hoop stringer 42 extending about each cylindrical outer surface 24, and an end hoop stringer 44 extending about each flat end 22 of the halves 16,18. Preferably, the longitudinal hoop stringer 40 is integral with the outer periphery and extends along a length of each of the halves 16,18 of the tank 20. Even more preferably, each half 16,18 includes a pair of opposing longitudinal hoop stringers 40 with corresponding longitudinal hoop stringers 40 engaging each other such that the tank 20 is enclosed by four longitudinal hoop stringers 40. Preferably, the radial hoop stringers 42 are integral with the cylindrical outer surface 24 and extend around each of the halves 16,18 of the tank 20 to the crossing 28 at the longitudinal hoop stringer 40 to define the joint 30 there between. Even more preferably, each half 16,18 includes a pair of longitudinal hoop stringers 40 such that the tank 20 includes four radial hoop stringers 42. The end hoop stringer 44 is integral with the flat ends 22 at the outer periphery of the halves 16,18 of the tank 20. Even more preferably, each half 16,18 includes a pair of opposing end hoop stringers 44 with corresponding end hoop stringers 44 engaging each other such that the tank 20 is enclosed by four end hoop stringers 44. It should be known and appreciated by one skilled in the art that the number and shape of the hoop stringers 26 used to enclose the tank 20 may vary depending upon the size and style of the tank 20 employed to house the pressurized materials.
A portion 31 of the hoop stringers 26 extend radially outward to increase a cross sectional area of the hoop stringers 26 for retaining the pressurized materials in the tank 20. Preferably, each portion 31 of the hoop stringer 26 terminates at an apex 32. Additionally, each hoop stringer 26 includes an inclined section 38 that leads to the apex 32. The hoop stringers 26 disposed about the outer periphery on each half 16,18 include the portion 31 extending radially outward and are fused together for form the tank 20. Preferably, there are two portions 31 of the hoop stringers 26 on each longitudinal hoop stringer 40 for extending across the cylindrical outer surface 24. Also, preferably, there is one portion 31 of the hoop stringers 26 on each end hoop stringer 44 for extending across the flat ends 22. The fusing of the portions 31, hoop stringers 26 and halves 16,18 is preferably accomplished by welding the hoop stringers 26 together. By example and not meant to be limiting, hot plate, vibration or ultrasonic welding can be performed to fuse the hoop stringers 26 and halves 16,18 together to form the tank 20.
A plurality of the portions 31 of the hoop stringers 26 extend radially outward at the crossing 28 or intersection of the hoop stringers 26 to increase a cross sectional area of the hoop stringers 26 at the joints 30. Preferably, there are two portions 31 of the hoop stringers 26 on each radial hoop stringer 42 for intersecting the portions 31 on each longitudinal hoop stringer 40. Once the halves 16,18 are put together to form the tank 20, the portions 31 of the hoop stringers 26 each define a pyramid 34 having four corners 36 at each joint 30. Each hoop stringer 26 defines a rectangular cross section extending outwardly from the tank 20 whereby the inclined sections 38 of the hoop stringers 26 define the four corners 36 of the pyramid 34 at each joint 30. It should be known and appreciated by one skilled in the art that the cross section of the hoop stringer 26 may be of any suitable design.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The invention may be practiced otherwise than as specifically described within the scope of the appended claims.
