Method of Construction for High Cycle Fatigue Resistant Pressure Vessels in Hydrogen Service
A method and system are described for a gas booster, preferably for use with hydrogen. A linear actuator can provide compression in first and second compression vessels. The liner of the compression vessels can be placed in compressive stress so that any cracks that form do not spread. Compressive stress can be applied using, at least, a shrink fit process or a wire wrapping process. The compressive stress will help the inner liner to resist fatigue and cracking due to pressure cycling and corrosion by materials being compressed in the compression vessels. This also protects the chamber jacket from wear and tear.
Latest Haskel International, LLC Patents:
The present disclosure is directed to compressors, and more particularly to powered gas boosters.
BACKGROUND OF THE INVENTIONGas boosters are commonly used to deliver pressurized gases for industrial processes or various manufacturing uses. Some gas boosters function with pistons or linear actuators. A retracting piston can create a low-pressure space in a barrel into which gas is drawn. A locking door may trap the gas in the barrel. Next the piston changes direction and presses down on the trapped gas, increasing the pressure of the gas which can be released to another location. The perpetual pressurization and depressurization of components, especially the barrel, in a gas booster can lead to fatigue issues. Fatigue is the weakening of a material caused by repeatedly applied loads.
In addition to fatigue, certain gas boosters that are used to compress hydrogen can suffer further problems from corrosion. Hydrogen can be particularly detrimental to certain metals used in gas booster construction. This is sometimes called the hydrogen embrittlement effect or hydrogen attack. A gas booster used for hydrogen will suffer fatigue effects that can be enhanced by the impact of hydrogen. The cycling of hydrogen in and out of a gas booster can lead to cracks which will grow due to further hydrogen flow and pressure cycling.
BRIEF SUMMARY OF THE INVENTIONOne possible embodiment under the present disclosure comprises a gas booster for compressing a gas. The gas booster can comprise a compression vessel. The compression vessel can comprise an inlet configured to receive a portion of gas from a supply line and a liner surrounded by a jacket, wherein jacket and the liner have been joined by a shrink fit process. The booster can further comprise a linear actuator, the linear actuator operable to compress the portion of gas in the compression vessel when moving in a first direction and operable to draw the portion of gas into the compression vessel when moving in a second direction opposite the first direction.
Another possible embodiment under the present disclosure can comprise a barrel for use in a gas booster. The barrel can comprise an inlet configured to receive a portion of gas from a supply line; a liner surrounded by a jacket, wherein jacket and the liner have been joined by a shrink fit process; and an outlet configured to direct gas out of the compression vessel. The barrel can be configured to receive a linear actuator therein for the purpose of compressing the portion of gas.
Another possible embodiment under the present disclosure comprises a method for manufacturing a gas booster. A chamber jacket can be provided that comprises an inner diameter. Next a chamber liner can be provided that comprises an outer diameter at least as large as the inner diameter of the chamber jacket. The chamber jacket can be heated such that the inner diameter becomes larger than the outer diameter of the chamber liner and the chamber liner can be placed within the chamber jacket. The chamber jacket can then be allowed to cool such that the chamber jacket engages the chamber liner to create a barrel and such that compressive stresses are applied to the chamber liner. The barrel can then be coupled to a linear actuator.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.
For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
In compressor cylinders or other pressure vessels, the pressure can cycle between a low suction pressure and a high exhaust pressure. This cycling creates stresses, and eventually, cracks in a chamber jacket or a liner on the interior of the jacket. High pressure situations may necessitate the use of thick chamber walls, which help to also alleviate the stresses from cycling. Lower pressure use scenarios may not need thick walls, but pressure cycling can still be a threat to cause stresses and cracks. In these cases, an alternative, lower cost method, of design and construction is needed. One method that has been applied to obtain high cycle performance in high pressure vessels is to eliminate the possibility of fatigue crack propagation. This is achieved when the construction of the vessel is such that when the pressure load is applied, the crack remains closed. If the crack doesn't open, then it cannot grow and the fatigue life is then longer.
Using a gas booster for pressurizing hydrogen can cause further problems due to hydrogen's detrimental effects. Currently, pressure vessels that operate in hydrogen service and subjected to fatigue must be designed using a defect tolerant design procedure. This means that first the fracture mechanics properties of the material being considered must be measured in hydrogen at the maximum service pressure. The properties are crack propagation properties and threshold stress intensity factor for hydrogen embrittlement. With these properties, a fatigue crack propagation life can be estimated assuming an initial crack size and geometry and growing this defect to failure. The property measurements are costly and can only be performed at a few laboratories. Furthermore, the resulting lives are usually very short because of the assumed initial crack size. These factors limit the application of this design method to lower cycle or static loading applications.
Solutions under the present disclosure to the problems described above include methods and systems for placing a booster liner in a compression state. Possible embodiments for creating such a compression state include a shrink fit process for placing a jacket around a liner, and also wire wrapping around a liner. Embodiments under the present disclosure can comprise methods of design and construction of pressure vessels for high cycle use in hydrogen service at pressures preferably below 40,000 psi. A preferred embodiment of the current disclosure can be used in hydrogen service applications (though other use scenarios are contemplated).
Certain embodiments under the present disclosure can use a shrink fit system or method to place a jacket around a liner in a gas booster. Generally, for lower pressure applications the vessel or compressor head radius ratio is thin or small, while for high pressure vessels, the radius ratios are large or thick. Thick walls allow for more methods of construction to obtain the desired stress state to prevent crack growth. But for hydrogen-based systems, such thick walls are typically not used and thin walls are used because of the lower pressures in hydrogen-based systems. For example, thick walls can be made with autofrettage techniques. During autofrettage a vessel can be subjected to high pressures, such as by a compressive outer barrel, that cause internal portions of the vessel to yield plastically. Once the pressure is released there are internal compressive residual stresses. With thin walls, the use of autofrettage will usually not be practical. One goal of the present disclosure is to provide a manufacturing technique for creating thin-walled vessels with increased strength for use in gas boosters, especially hydrogen carrying gas boosters. Instead of, or in addition to, autofrettage, embodiments under the present disclosure can comprise the use of a shrink fit liner on the interior surface of a pressure vessel. In certain embodiments under the present disclosure, shrink fit construction can be used to place an inside liner in a compression cylinder in sufficient compression such that when the pressure is applied during use, any crack present would be prevented from opening and thus prevented from growing.
Referring to
Referring to
A preferred method of combining the liners and chambers according to the concepts described herein involves a shrink fit process, wherein the chamber jacket is heated so that it expands and a liner is inserted therein. Once combined (as the chamber jacket cools), the magnitude of the resultant stress at the pressure boundary of the liner is more compressive than the magnitude of an applied pressure. The pressure on the liner operates to prevent any crack, should one initiate (or be pre-existent), from opening further. The choice of materials and the shrink fit process should produce sufficient compression in the liner. The shrink fitting can expand the jacket and place it in a condition of tension. To ensure that the jacket has sufficient life, the jacket requires a maximum threshold of linear axial indication and should be inspected and tested for integrity by means of non-destructive testing prior to assembly to ensure that there are no defects present. Threshold values for various materials under various loading conditions are found in construction codes such as ASME section VIII, Division 3, Rules for High Pressure Vessels.
The material comprising a liner 417, 457 will preferably be a material resistant to corrosion or the detrimental effects of hydrogen. However, the material can vary. Some embodiments under the present disclosure may be for systems without hydrogen and may therefore use a different material than in hydrogen-based systems. Stainless steel, such as 15-5PH, is a preferred material for a chamber jacket. Stainless steel is useful because of its cost, availability, and usability in various construction techniques. Other embodiments can comprise other metals, alloys, or other appropriate materials.
The method of
The method of
Gas boosters like those described in the current disclosure have a number of uses. Uses can include: hydrogen filling stations; charging high-pressure gas cylinders and receivers; gas assisted plastic injection molding; hydraulic accumulator charging; charging air bag storage vessels; missile and satellite launch and guidance systems; component testing; laser cutting and welding; oilfield high volume gas testing; biogas charging; and more. Embodiments under the current disclosure can be implemented in any of these use scenarios.
Gas boosters like those described in the present disclosure can be coupled with different types of drives, such as a hydraulic drive, pneumatic drive, electrical drive, or can be driven using other appropriate technologies.
Sometimes gas boosters are mobile, such as the truck embodiment shown in
Preferred embodiments of the current disclosure comprise dual-stage gas boosters. However, the teachings can be applied to single stage boosters. A possible single stage embodiment can be seen in
Dimensions of chamber jackets and liners can vary as needed in a given use scenario.
How thick to make the liner, both in absolute measurements and in comparison to a jacket, can depend on a given embodiment. Factors to consider can include the pressures that will occur during use; the type of gas/material being compressed and its corrosive relationship to a liner or jacket; space constraints; desired length of a jacket and liner; and other factors.
Both jackets and liners under the present disclosure can comprise a variety of materials. Various types of steels and steel alloys are preferred materials for both jackets and liners, though other materials are possible. Preferred jacket embodiments can use SA 564, type 630 or XM-12. Preferred liner embodiments can use SA 705 type 630 or XM-12. The jacket and liner will preferably comprise cylinder-shaped units. Other shapes are possible.
Operating conditions for compression stages or vessels under the present disclosure can vary. Typical operating pressures can be 4,500 PSIG, 9,000 PSIG, and 15,000 PSIG. Design pressures may be 14,600 PSIG, 25,500 PSIG, and 41,800 PSIG in such embodiments. Operating temperatures may range from −40 F to 400 F in such embodiments. Embodiments such as these can typically withstand nearly 80 million pressure cycles. Preloading can take the form of 410 ft-lb on eight 24×3 threaded tie rods.
In addition to embodiments using a shrink fit process, compressive forces can be applied to a liner using a wire-wrapped embodiment. An embodiment of a wire-wrapped compression stage can be seen in
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
Claims
1. A gas booster for compressing a gas, comprising:
- a compression vessel comprising: an inlet configured to receive a portion of gas from a supply line; a liner surrounded by a jacket, wherein jacket and the liner have been joined by a shrink fit process; and
- a linear actuator, the linear actuator operable to compress the portion of gas in the compression vessel when moving in a first direction and operable to draw the portion of gas into the compression vessel when moving in a second direction opposite the first direction.
2. The gas booster of claim 1 further comprising a second compression vessel, comprising:
- a second compression vessel comprising; a second inlet configured to receive the portion of gas from the compression vessel; and a second liner surrounded by a second jacket, wherein the second jacket and the second liner have been joined by a shrink fit process;
- wherein the linear actuator is operable to compress the portion of gas in the second compression vessel when moving in the second direction and to draw the portion of gas into the second compression vessel when moving in the first direction.
3. The gas booster of claim 1 wherein the portion of gas comprises hydrogen.
4. The gas booster of claim 1 wherein the linear actuator is hydraulically driven.
5. The gas booster of claim 1 wherein the linear actuator is pneumatically driven.
6. The gas booster of claim 2 wherein the compression vessel has a larger diameter than the second compression vessel.
7. The gas booster of claim 1 wherein the jacket comprises a steel alloy.
8. The gas booster of claim 1 wherein the liner comprises a steel alloy.
9. A barrel for use in a gas booster, the barrel comprising:
- an inlet configured to receive a portion of gas from a supply line;
- a liner surrounded by a jacket, wherein jacket and the liner have been joined by a shrink fit process; and
- an outlet configured to direct gas out of the compression vessel;
- wherein the barrel is configured to receive a linear actuator therein for the purpose of compressing the portion of gas.
10. The barrel of claim 9 wherein the portion of gas comprises hydrogen.
11. The barrel of claim 9 wherein the linear actuator is hydraulically driven.
12. The barrel of claim 9 wherein the linear actuator is pneumatically driven.
13. The barrel of claim 9 wherein the liner comprises a cylindrical shape.
14. The barrel of claim 9 wherein the jacket comprises a cylindrical shape.
15. The barrel of claim 9 wherein the liner comprises a steel alloy.
16. The barrel of claim 9 further comprising a check valve configured to close the inlet once the portion of gas enters the barrel.
17. A method for manufacturing a gas booster:
- provide a chamber jacket comprising an inner diameter;
- provide a chamber liner, the chamber liner comprising an outer diameter at least as large as the inner diameter of the chamber jacket;
- heat the chamber jacket such that the inner diameter becomes larger than the outer diameter of the chamber liner;
- place the chamber liner within the chamber jacket;
- allow the chamber jacket to cool such that the chamber jacket engages the chamber liner to create a barrel and such that compressive stresses are applied to the chamber liner; and
- couple the barrel to a linear actuator.
18. The method of claim 17 further comprising creating a second barrel and coupling the second barrel to the linear actuator.
19. The method of claim 18 wherein the barrel and second barrel are coupled to opposite ends of the linear actuator.
20. The method of claim 17 further comprising coupling a gas outlet of the barrel to a gas inlet of the second barrel.
Type: Application
Filed: Nov 10, 2017
Publication Date: May 16, 2019
Applicant: Haskel International, LLC (Burbank, CA)
Inventors: Pooya Mahmoudian (Glendale, CA), Brian A. Burrows (Granada Hills, CA), Paul Harrison (Washington), Greg Terterian (Granada Hills, CA)
Application Number: 15/809,508