CRYOGENIC PUMP FLANGE
A flange (50) for a pump (10) comprises a first face (65); a second faces (85); a passageway (110) for cryogenic fluid flow extending from the first face (65) to the second face (85), and the passageway (110) for a pipe (40) and comprising a first portion (120) of a first diameter and a second portion (130) of a second diameter greater than the first diameter, wherein when the pipe (40) has an outer diameter that is smaller than the second diameter, a gap (140) is formed between the pipe (40) and the passageway (110) where the pipe (40) passes through the second portion (130); and a first annular groove (155) in one of the first face (65) and the second face (85) and extending around the passageway (111), wherein the first annular groove (155) in cooperation with the passageway (111) forms a bellows. The gap (140) and bellows increase the thermal resistance between the passageway (111) and the flange (50), and the bellows allows for flexure during thermal contractions of the flange reducing thermal stress on welded fluid seals.
The present application relates to an arrangement for reducing the condensation of humidity around a flange for a cryogenic pump assembly, and the accumulation of frost and ice, and the freezing of a pump drive unit, that might otherwise be caused by flowing a cryogenic fluid through the flange.
BACKGROUND OF THE INVENTIONGases can be stored at much higher densities when stored in liquefied form. Compared to a compressed gas stored in gaseous form, a gas can be stored at relatively low pressures if stored in liquefied form below or at its boiling point, such as below about −161.5° C. for a typical blend of natural gas. In this disclosure, “cryogenic” is used to describe fluids at such low temperatures and apparatus, such as a “cryogenic pump” that is designed to handle cryogenic fluids at cryogenic temperatures.
Cryogenic pumps are known for delivering a cryogenic fluid from a thermally insulated storage vessel. Such cryogenic pumps have what is referred to herein as a “cold end” which is immersed in the cryogenic fluid. Typically, cryogenic fluid is fed by gravity into a sump from which it is pumped, or the cold end can comprise a pump assembly that is disposed within the cryogen space defined by storage vessel itself. The drive unit for such a cryogenic pump is referred to herein as the “warm end” and it is usually located outside of the storage vessel to avoid introducing heat from the drive unit into the cold cryogen space defined by the storage vessel. The warm end is also typically located separated spaced apart and/or thermally insulated from the cold end and the delivery pipe exiting from the storage vessel to preventing freezing in the drive unit, especially when the drive unit is a hydraulic drive that uses hydraulic fluid pressure to actuate the cryogenic pump.
In vehicle applications there are often space constraints because of the limited space for mounting the fuel system, and accordingly, a more compact arrangement is preferred. Therefore, it is advantageous to mount the drive unit on, or close to, the flange that seals the opening through which the pump assembly is installed. In addition, it is desirable to reduce the number of heat transfer paths between the cryogen space and the surrounding environment, so it is preferred to have the delivery pipe, in addition to fill pipes and drain pipes, pass through the same flange. However, this can result in freezing of the hydraulic fluid in a hydraulic drive.
The delivery, fill and drain pipes are preferably welded to the flange to fluidly seal the interior of the storage vessel from the external environment. As the temperature of the flange decreases, due to cryogenic fluid, such as liquefied natural gas (LNG), passing through one or more of these pipes, the flange contracts putting stress on these weld joints, which can fatigue and compromise the fluid seal.
The applicant has designed and commercialized a different type of cryogenic pump which comprises a vaporizer integrated with the pump assembly, as disclosed by U.S. Pat. No. 7,607,898. With this arrangement, at the warm end there is no problem with mounting the drive unit on the same flange which the delivery pipe passes through because the vaporized fluid is warmer than the cryogenic fluid.
However, for systems that do not use a cryogenic pump integrated with a vaporizer, there is a need for a compact arrangement that allows for a warm end with a drive unit mounted on or close to the same flange that the delivery pipe passes through.
SUMMARY OF THE INVENTIONAn improved flange for a pump comprises first and second faces and a passageway for cryogenic fluid flow extending from the first face to the second face, and at least one of (1) the passageway is for a pipe and comprises a first portion of a first diameter and a second portion of a second diameter that is greater than the first diameter, wherein when the pipe has an outer diameter that is smaller than the second diameter, a gap is formed between the pipe and the passageway where the pipe passes through the second portion; and (2) a first annular groove in one of the first face and the second face and extending around the passageway, wherein the first annular groove in cooperation with the passageway forms a bellows.
The pipe, which can be a fill pipe, a delivery pipe or a drain pipe, can be in contact with an inner wall of the first portion of the passageway. The pump can be a cryogenic pump for pumping a cryogenic fluid from a storage vessel to which the flange is mounted.
In preferred embodiments, the gap is annular. The passageway can be at an oblique angle to at least one of the first face and the second face. A first opening is formed by the intersection of the first portion of the passageway with the first face, and a second opening is formed by the intersection of the second portion of the passageway with the second face. It is preferable that the first opening is further away from a longitudinal axis of a mounting location for a drive unit, compared to the second opening The second opening can be located within an area surrounded by a sleeve within which the pump is inserted when installed.
An improved flange assembly for a pump comprises a process fluid pipe and a flange. The flange comprises a first face, a second face and a passageway for cryogenic fluid flow extending from the first face to the second face, and at least one of (1) the passageway is for the process fluid pipe and comprises a first portion of a first diameter and a second portion of a second diameter that is greater than the first diameter, wherein when the process fluid pipe has an outer diameter that is smaller than the second diameter, a gap is formed between the process fluid pipe and the passageway where the process fluid pipe passes through the second portion; and (2) a first annular groove in one of the first face and the second face and extending around the passageway, wherein the first annular groove in cooperation with the passageway forms a bellows.
In a preferred embodiment, the flange comprises a bore extending from the first face to the second face and having a diameter equal to the second diameter. The flange assembly further comprises an annulus having an inner diameter equal to the first diameter. The passageway is formed by inserting the annulus into the bore.
The process fluid pipe can be welded to the flange. In a preferred embodiment the flange is disc shaped, but other shapes are possible in other embodiments. The passageway can be at an oblique angle to at least one of the first face and the second face. A first opening is formed by the intersection of the first portion of the passageway with the first face, and a second opening is formed by the intersection of the second portion of the passageway with the second face. In a preferred embodiment the first opening is further away from a longitudinal axis of the flange compared to the second opening
An improved multi-functional flange for (a) attaching to a corresponding flange on storage vessel, (b) for supporting a pump assembly, and (c) for mounting a hydraulic drive unit, comprises a first face, a second face and a passageway for cryogenic fluid flow extending from the first face to the second face, and at least one of (1) the passageway is for a pipe and comprises a first portion of a first diameter and a second portion of a second diameter that is greater than the first diameter, wherein when the pipe has an outer diameter that is smaller than the second diameter, a gap is formed between the pipe and the passageway where the pipe passes through the second portion; and (2) a first annular groove in one of the first face and the second face and extending around the passageway, wherein the first annular groove in cooperation with the passageway forms a bellows.
The pipe can be in contact with an inner wall of the first portion of the passageway. In a preferred embodiment, the multi-functional flange comprises at least one hydraulic fluid passageway in fluid communication with the hydraulic drive unit.
Referring to
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The thermal resistance between process fluid pipe 40 and flange 50 is increased by gap 140 since the contact area between the pipe and the flange is reduced. Normally both pipe 40 and flange 50 are made from metal, which is a better conductor of heat than air occupying gap 140. The gap decreases cooling effect on flange 50 caused by the flow of cryogenic fluid through pipe 40, thereby reducing the likelihood of the hydraulic fluid freezing and reducing condensation of humidity and frost/ice build-up around warm end assembly 20.
Passageway 110 is at an oblique angle to both faces 65 and 85, such that opening 125 is further from longitudinal axis 15 than opening 135. Referring now to
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While particular elements, embodiments and applications of the present invention have been shown and described, it will be understood, that the invention is not limited thereto since modifications can be made by those skilled in the art without departing from the scope of the present disclosure, particularly in light of the foregoing teachings.
Claims
1. A flange for a pump comprising:
- a first face;
- a second face;
- a passageway for cryogenic fluid flow extending from said first face to said second face, and at least one of: said passageway for a pipe and comprising a first portion of a first diameter and a second portion of a second diameter greater than said first diameter, wherein when said pipe has an outer diameter that is smaller than said second diameter a gap is formed between said pipe and said passageway where said pipe passes through said second portion; and said passageway for a pipe and comprising a first portion of a first diameter and a second portion of a second diameter greater than said first diameter, a first annular groove in one of said first face and said second face and extending around said first and second portions of said passageway, wherein said first annular groove in cooperation with said passageway forms a bellows and
- a first annular groove in one of said first face and said second face and extending around said passageway, a second annular groove extending from an opposite face as said first annular groove and around said first annular groove, wherein said first annular groove in cooperation with said passageway forms a bellows.
2. The flange of claim 1, wherein said pipe is in contact with an inner wall of said first portion of said passageway.
3. The flange of claim 1, wherein said pump is a cryogenic pump for pumping a cryogenic fluid from a storage vessel to which said flange is mounted.
4. The flange of claim 1, wherein said gap is annular.
5. The flange of claim 1, wherein said passageway is at an oblique angle to at least one of said first face and said second face.
6. The flange of claim 1, wherein a first opening is formed by the intersection of said first portion of said passageway with said first face, and a second opening is formed by the intersection of said second portion of said passageway with said second face, said first opening being further away from a longitudinal axis of a mounting location for a drive unit, compared to said second opening.
7. The flange of claim 6, wherein said second opening being located within an area surrounded by a sleeve within which said pump is inserted when installed.
8. The flange of claim 1, wherein said first face is associated with said first portion of said passageway and said annular groove is in said first face.
9. The flange of claim 8, wherein a second annular groove formed between the pipe and the second portion of the passageway is at least one of filled with a low thermal conductivity material and sealed at the second face to reduce accumulation of moisture in the second annular groove.
10. (canceled)
11. A flange assembly for a pump comprising:
- a process fluid pipe;
- a flange comprising: a first face; a second face; a passageway for cryogenic fluid flow extending from said first face to said second face, and at least one of: said passageway for said process fluid pipe and comprising a first portion of a first diameter and a second portion of a second diameter wherein said second diameter is greater than said first diameter, wherein when said process fluid pipe extends through said passageway a gap exists between an inner wall of said second portion of said passageway and said process fluid pipe; and a first annular groove in one of said first face and said second face and extending around said passageway, wherein said first annular groove in cooperation with said passageway forms a bellows.
12. The flange assembly of claim 11, wherein said flange comprises a bore extending from said first face to said second face and comprising a diameter equal to said second diameter, said flange assembly further comprising an annulus comprising an inner diameter equal to said first diameter, said passageway formed by inserting said annulus into said bore.
13. The flange assembly of claim 11, wherein said process fluid pipe is welded to said flange.
14. The flange assembly of claim 11, configured in at least one of the following ways:
- wherein said flange is disc shaped; and
- wherein said gap is annular.
15. (canceled)
16. The flange assembly of claim 11, wherein said passageway is at an oblique angle to at least one of said first face and said second face.
17. The flange assembly of claim 11, wherein a first opening is formed by the intersection of said first portion of said passageway with said first face, and a second opening is formed by the intersection of said second portion of said passageway with said second face, said first opening further away from a longitudinal axis of said flange compared to said second opening.
18. The flange of claim 11, wherein said first face is associated with said first portion of said passageway and said annular groove is in said first face.
19. (canceled)
20. A multi-functional flange for (a) attaching to a corresponding flange on storage vessel, (b) for supporting a pump assembly, and (c) for mounting a hydraulic drive unit, said multi-functional flange comprising:
- a first face;
- a second face;
- a passageway for cryogenic fluid flow extending from said first face to said second face, and at least one of: said passageway for a pipe and comprising a first portion of a first diameter and a second portion of a second diameter greater than said first diameter, wherein when said pipe has an outer diameter that is smaller than said second diameter a gap is formed between said pipe and said passageway where said pipe passes through said second portion; and a first annular groove in one of said first face and said second face and extending around said passageway, wherein said first annular groove in cooperation with said passageway forms a bellows.
21. The multi-functional flange of claim 20, comprising at least one hydraulic fluid passageway in fluid communication with said hydraulic drive unit.
22. The flange of claim 20, wherein said first face is associated with said first portion of said passageway and said annular groove is in said first face.
23. The flange of claim 20, further comprising a second annular groove extending from an opposite face as said first annular groove and around said first annular groove, wherein said first and said second annular grooves in cooperation with said passageway forms a bellows.
Type: Application
Filed: Jul 11, 2014
Publication Date: Jun 2, 2016
Inventors: Ziyuan REN (Beijing), Raymundo A. SAENZ (New Westminster), Robbi L. MCDONALD (Richmond), Ankur H. VAYEDA (Vancouver), Gregory C. HARPER (North Vancouver), Kenneth W. KRATSCHMAR (Vancouver), Michael EBBEHOJ (Vancouver)
Application Number: 14/904,412