This application relates to a filter bypass valve which may be utilized in a fuel line for an aircraft engine.
Aircraft engines are typically provided by gas turbine engines. Fuel is delivered into a combustor section, and sometimes other portions of the gas turbine engine. The fuel is driven by a fuel pump from a fuel sump, and passes through a filter on the way to the engine.
Should the filter become clogged, pressure will build up in the filter. Thus, it is known to include a bypass valve to allow flow around the filter should the filter become clogged.
The existing bypass valves may sometimes result in undesirably high pressure losses.
In an embodiment of the invention, a piston extends along an axial dimension with a seal face at an upstream end. A closure face closes off a cavity defined radially inwardly and downstream of the upstream end. The closure face is spaced from the upstream end by a first distance. The piston has a cavity extending in a downstream direction away from an opposed side of the closure face to a second end. A piston diameter is defined to an outer periphery of a cylindrical portion forming the seal face. A ratio of the piston diameter to the first distance is between 3.85 and 4.43.
In another embodiment of the invention, a valve sleeve body extends between an upstream end and a second end. A sleeve internal bore extends between the upstream and second end. Windows are formed in the valve sleeve to allow flow of fluid from the bore through the windows and to a downstream port. The bore has an inner diameter. The window has an axial dimension and a circumferential dimension. A ratio of the inner diameter to the axial dimension is between 1.04 and 1.07. A ratio of the inner diameter to the circumferential direction is between 1.81 and 1.88. A bypass valve incorporating the valve sleeve and piston, and a fuel supply system incorporating the bypass valve are also disclosed.
These and other features may be best understood from the following drawings and specification.
When the pressure upstream of the filter 26 is below a predetermined limit, a spring 46 biases a piston 36 against a valve seat defined by a sleeve 15 to prevent flow through the bypass valve 29. On the other hand, should the pressure exceed the predetermined limit, then the pressure will act in a direction X as shown in
In the valve 29, the valve sleeve 15 defines an inner upstream bore 32 extending to an upstream end 101, and a cylindrical surface or face 34. A downstream bore 136 receives the piston 36.
Face 34 of the sleeve 15 will provide a valve stop for piston 36, which is received in a cavity downstream of the face 34. As shown, piston 36 is generally cylindrical in shape and has a surface 38 abutting the face 34 such that the valve 29 seals along a generally cylindrical face. This generally cylindrical seal face is across an enlarged area compared to other pressure relief valves.
The piston 36 has a cavity 42 at an upstream end, and is defined by a closure wall face 40 that separates the cavity 42 from a downstream cavity, or spring cavity 16, within the piston 36. A cylindrical cup or boss 102 extends upstream from face 40. On an opposed side of the wall face 40, a spring 46 sits in cavity 16 and biases the face 38 into contact with the stop face 34. The piston 36 has a cylindrical outer surface 41 closely received in an inner surface of downstream bore 136 of the sleeve 15 to prevent fluid leakage therebetween.
As can be appreciated, the cavity 16 is defined by a first enlarged cylindrical portion 9 on the piston 36, and a smaller portion 10 spaced in an upstream direction relative to the portion 9. The spring 46 sits in the smaller portion 10.
A closure 60, shims 62, and seal 64 are at a downstream end of the valve 29. Sleeve 15 is threaded 100 into closure 60. The shims 62 provides a stop for the spring in the downstream end.
As shown in
As can be appreciated, in assembling the valve, the piston 36 is inserted into the downstream bore 136, with the shim 62 and spring 46 received in cavity 16. Shim 62 is then placed in a cavity 14 in closure 60, and the sleeve 15 is threaded at 100 into the closure 60. The closure 60 may then be threaded, as shown at 13, into a main housing 12.
The valve will then operate as mentioned above.
In embodiments, a ratio of d1 to d5 was between 1.07 and 1.0. A ratio of d5 to d3 was between 0.91 and 1.02, and a ratio of d5 to d4 was between 1.55 and 1.85. The diameter of a spool bore at 136 is d6. In one embodiment, d6 was 0.6 inch (1.52 cm). In embodiments, a ratio of d1 to d6 was between 0.99 and 1.01.
In a method of replacing a piston or valve sleeve in a bypass valve, at least one of a piston and sleeve is removed from a bypass valve housing, and at least one of a replacement valve or sleeve replaces the removed valve or sleeve. The valve or sleeve, which is replaced, is generally as disclosed above.
With a valve made according to the above description, the pressure losses across the valve are dramatically reduced when compared to the prior art.
Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
Number | Name | Date | Kind |
---|---|---|---|
3339574 | Erb et al. | Sep 1967 | A |
4458713 | Wernberg | Jul 1984 | A |
4876857 | Feltz et al. | Oct 1989 | A |
5013220 | Nakagawa et al. | May 1991 | A |
6195978 | Futa, Jr. | Mar 2001 | B1 |
6294083 | Lee et al. | Sep 2001 | B1 |
6328056 | Kumar et al. | Dec 2001 | B1 |
6582593 | Wolford et al. | Jun 2003 | B2 |
6583525 | Dyer et al. | Jun 2003 | B2 |
6789562 | Dyer et al. | Sep 2004 | B2 |
6972087 | Wolford et al. | Dec 2005 | B2 |
7322373 | Lewis | Jan 2008 | B2 |
7981279 | Pabst | Jul 2011 | B2 |
8015825 | Elder et al. | Sep 2011 | B2 |
8083938 | Lepine et al. | Dec 2011 | B2 |
8118998 | Bagci et al. | Feb 2012 | B2 |
8181669 | Dehais et al. | May 2012 | B2 |
8316880 | Grosskopf et al. | Nov 2012 | B2 |
8485218 | Lemmers et al. | Jul 2013 | B2 |
20100243940 | Terada et al. | Sep 2010 | A1 |
20100283333 | Lemmers et al. | Nov 2010 | A1 |
20100283338 | Grosskopf et al. | Nov 2010 | A1 |
Number | Date | Country |
---|---|---|
2048801 | Dec 1980 | GB |
101120841 | Mar 2012 | KR |
Number | Date | Country | |
---|---|---|---|
20140311585 A1 | Oct 2014 | US |