Fluid handling – Larner-johnson type valves; i.e. – telescoping internal valve...
Reexamination Certificate
2000-01-14
2001-11-27
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Larner-johnson type valves; i.e., telescoping internal valve...
C137S625300, C251S129110
Reexamination Certificate
active
06321774
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a control valve for cryogenic use, in particular, a control valve for controlling a flow of cryogenically liquefied rocket fuel.
BACKGROUND INFORMATION
Control valves used for supplying cryogenically liquified fuel to larger rocket engines must operate under extreme operating conditions. For example, they must operate at extremely low temperature and are subject to high mass flow and high pressure. Furthermore, the switching times for opening and closing the valve must be short and the energy requirements low. The effects of such operating conditions must be taken into consideration in the design and construction of such control valves.
Control valves for use with cryogenically liquefied rocket fuel are known in which the switching forces required for opening and closing the valve are essentially determined by flow resistance or interference forces that act on the valve plunger and other movable valve components, especially as the valve plunger is being moved to open or close the valve. With these known types of control valves, the flow forces are not reduced or compensated by the structural design of the valves, and therefore such forces undesirably increase the drive power required for opening or closing the valve, particularly when large nominal dimensions, high nominal pressures, and short switching times are required.
SUMMARY OF THE INVENTION
In view of the above, it is an object of the invention to provide a control valve that is suitable for controlling a liquid flow, and particularly a cryogenic liquid flow, and that achieves short switching times, requires reduced driving forces for opening and closing the valve, and has low drive power requirements. More particularly, it is an object of the invention to provide a valve arrangement in which the hydraulic forces acting on the moving components of the valve can be minimized, compensated or eliminated. The invention further aims to avoid or overcome the disadvantages of the prior art and to achieve additional advantages, as are apparent from the present description.
The above objects have been achieved according to the invention in a control valve especially for use with cryogenically liquified rocket propellant. Through its special structural design, the valve arrangement reduces or provides compensation of the hydraulic forces that act on the valve plunger. This results in a reduction of the switching forces required to open and close the valve and, thus, in a reduction of the required drive power.
The control valve preferably has a coaxial inlet port and outlet port. A regulating or control sleeve with flow slots around its circumference is centrally arranged in the valve housing or casing between the inlet and outlet ports, such that the sleeve is slidably displaceable in an axial direction. The regulating sleeve is connected to a drive linkage that in turn is connected to a drive mechanism, for example, a motor-driven gear with a drive shaft or stroke rod. The motor and gear are preferably mounted outside of the valve casing proper, such that they are not in the path of the flow. The drive shaft or stroke rod is arranged in the valve casing perpendicularly to the axial direction in which the regulating sleeve is slidable, and perpendicularly to the net overall direction of flow from the inlet port to the outlet port. Rocket propellant flows into the control valve at the inlet port and flows along a generally circularshaped flow channel that extends around the drive chamber which houses the drive linkage and then meets radially with the regulating sleeve. The regulating sleeve is slidingly displaced by the drive mechanism and the drive linkage in the axial direction, relative to the position of the drive mechanism, thereby selectively moving the flow slots into a position that will allow flow from the flow channel through a cross-section of the flow slots into the outlet port, or into a position that will block flow.
The embodiments of the invention provide extensive compensation or avoidance of the influence of the hydraulic forces in open as well as in closed valve positions. The drive forces required to switch the valve and, consequently, the power requirements to drive the valve are minimized. This is achieved for both the open and closed valve positions. In the closed valve position, the pressure of the rocket fuel is applied exclusively radially onto the regulating sleeve. Thus, there is no force in a direction opposite the direction of opening displacement of the regulating sleeve, and there is no force against which the regulating sleeve must be actively pushed to maintain the closed position. Since the drive mechanism does not have to overcome the flow force to switch the valve position, the power required to switch the control valve is also not influenced by the flow force. In the open valve position (and in intermediate, partially open positions), the regulating sleeve is not subject to substantial force influence from the flow forces because the flow forces are radially balanced and substantially perpendicular relative to the sliding direction of the regulating sleeve, and because of the desired pressure compensation between the flow channel and the drive chamber.
REFERENCES:
patent: 4294286 (1981-10-01), Ohumi
patent: 4611630 (1986-09-01), Muchow et al.
patent: 3933169 (1991-04-01), None
patent: 29706688 (1997-08-01), None
patent: 0257906 (1988-03-01), None
patent: 0743476 (1996-11-01), None
Daimler-Chrysler AG
Fasse W. F.
Fasse W. G.
Michalsky Gerald A.
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