This application claims the priority of German Patent Application, Serial No. 20 2008 001 458.1, filed Feb. 1, 2008, pursuant to 35 U.S.C. 119(a)-(d), the content of which is incorporated herein by reference in its entirety as if fully set forth herein.
The present invention relates to a high-pressure valve assembly.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
High-pressure valve assemblies are used in high-pressure pumps by which a fluid is pressurized to a pressure of, for example, 4000 bar and above. The valve assembly has a pressure valve having a spring-loaded tappet which is movable in an axial direction and has an end surface to form a sealing surface resting against a complementary end surface of a valve body, when assuming a sealing position, so as to snugly seal a channel during a suction step. The suction valve includes a spring-loaded closure member of annular plate shape which rests on the other end surface of the valve body, when the fluid is set under pressure by a plunger and forced through the channel. In this situation, the closure member snugly seals an inlet on a suction side.
Practice has shown that the relevant parts of the valve assembly are exposed to significant mechanical stress as a consequence of the very high fluid pressure, e.g. tensile stress, causing a notch effect in particular in the outlet zone of the channel. As a result, the service life of the valve assembly is reduced and the applicability of the valve assembly for very high pressures is limited.
It would therefore be desirable and advantageous to provide an improved high-pressure valve assembly to obviate prior art shortcomings.
According to one aspect of the present invention, a high-pressure valve assembly includes a flange defining an axis, a valve body projecting into the flange, a static ring seal sealing the valve body against the flange, a spring-loaded closure member supported for movement in a direction of the axis on one side of the valve body to form a suction valve, a spring-loaded tappet supported for movement in the direction of the axis on another side of the valve body in opposition to the one side to form a pressure valve, and a channel connecting the suction valve with the pressure valve and having one end porting into a pressure chamber of the valve body adjacent to the pressure valve, said pressure chamber extending in axial direction of the tappet and sized to extend substantially above a bottom edge of the ring seal.
As in accordance with the present invention, the pressure-side tappet, when assuming the sealing position, projects into the chamber which has a bottom area in which the channel connects, an equilibrium of the hydrostatic pressure is established in radial direction when the tappet is moved axially in opposition to the spring force upon opening of the pressure valve, so that the presence of tensile stress in the outlet zone of the channel is avoided. As a result, there is no notch effect so that the stress on the valve body is minimized. The service life of the high-pressure valve assembly is thus increased and higher pressures can be absorbed so that the versatility of the valve assembly is significantly improved.
According to another advantageous feature of the present invention, the pressure chamber has a sidewall which may have at least one region to provide an axial guide surface for the tappet. As a result of the continuous support of the tappet in the valve body, the stress resistance of the high-pressure valve assembly is further enhanced.
According to another advantageous feature of the present invention, the closure member and the tappet may be arranged in coaxial disposition.
According to another advantageous feature of the present invention, the closure member may have a stepped pin which is movably supported in a bore of the valve body for guidance in the direction of the axis. The tappet may also have a stepped pin which projects into the pressure chamber and rests upon the guide surface.
According to another advantageous feature of the present invention, the stepped pin of the closure member may have a shoulder to define a sealing surface which rests against a complementary sealing surface of the valve body, when the closure member assumes a sealing position. The sealing surface of the shoulder may hereby be conical or flat (planar), i.e. transversely to the length axis.
According to another advantageous feature of the present invention, the stepped pin of the tappet may have a shoulder to define a sealing surface which rests against a complementary sealing surface of the valve body, when the tappet assumes a sealing position. The sealing surface of the shoulder may hereby be conical or flat (planar), i.e. transversely to the length axis. Suitably, the sealing surface of the tappet may have an end surface formed with a bevel.
According to another advantageous feature of the present invention, the valve body may have a concentric chamber adjacent to the suction valve, with the chamber having a wall surface having at least one region forming an axial guidance for the closure member.
According to another advantageous feature of the present invention, the valve body may have a bore for movably supporting and guiding the closure member. This design is beneficial as far as manufacture and operation are concerned.
Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which:
Throughout all the figures, same or corresponding elements may generally be indicated by same reference numerals. These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way. It should also be understood that the figures are not necessarily to scale and that the embodiments are sometimes illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted.
Turning now to the drawing, and in particular to
The housing 1 is provided with inlet bores 4 for routing a fluid into a suction space 11 via a suction line 5 arranged in the valve body 6. The supply of fluid is controlled by a closure member 8 which is urged by spring 81 to rest snugly against the valve body 6 in order to close the suction line 5. The closure member 8 is formed with a pin 9 which extends axially for movement in a bore 19 of the valve body 6. The bore 19 thus forms a guidance for the pin 9 and hence also for the closure member 8.
When the suction line 5 is sealed off by the closure member 8, a plunger 18 forces fluid to flow through a channel 10 in the valve body 6 into a pressure chamber 12 of the valve body 6. The channel 10 ends hereby in a bottom region of the pressure chamber 12. Positioned in the pressure chamber 12 in coaxial relationship to the plunger 18 and the closure member 8 is a spring-loaded tappet 13 of a pressure valve to snugly seal the channel 10, when fluid is drawn in. The tappet 13 has a stepped configuration to include a pin 22, which projects into the pressure chamber 12, and a circumferential shoulder, which forms a sealing surface 17 for cooperation with a complementary sealing surface of the valve body 6. Both the sealing surface 17 of the tappet 13 and the associated sealing surface of the valve body 6 have a conical configuration. Likewise the closure member 8 has a sealing surface 20 which snugly rests upon a complementary sealing surface of the valve body 6.
The pressure chamber 12 is sized in such a way that a major part thereof extends above a bottom edge 23 of the static ring seal 7, when viewed in axial direction of the tappet 13. In the area of the stepped pin 22 of the tappet 13, the pressure chamber 12 forms guide surfaces 14 on which at least some areas of the outer surface area of the tappet 13 rest for axial guidance.
While the invention has been illustrated and described in connection with currently preferred embodiments shown and described in detail, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. The embodiments were chosen and described in order to best explain the principles of the invention and practical application to thereby enable a person skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.
Number | Date | Country | Kind |
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20 2008 001 458 U | Feb 2008 | DE | national |
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4111392 | Edelmann | Sep 1978 | A |
4551077 | Pacht | Nov 1985 | A |
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7779748 | Alaze et al. | Aug 2010 | B2 |
Number | Date | Country | |
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20090194717 A1 | Aug 2009 | US |