Double-Piston Flow Regulating Valve for Equal Dual-Channel Flow
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Solution Overview
Problem
Existing volume flow regulating valves in roll stands for metallic material rolling are inadequate in distributing fluid medium or coolant uniformly to hydrostatic pockets, especially when the roll pin is inclined, and exhibit high pressure losses.
Innovation Solution
A volume flow regulating valve with a dumbbell-shaped double piston and peripheral pressure chambers, where the length of the centre member ensures equal opening cross-sections in drain channels, and plungers are used to adjust the piston position based on pressure ratios, ensuring equal volume flow in both channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If throttles or restrictors are used in the bores of the bearing bush, then the roll pin can be journalled hydrostatically, but the volume flow distribution to the two hydrostatic pockets is non-uniform and pressure losses are high (above 200 bars)
Solution Approach 1:
The single bore is segmented into two separate drain channels (first drain channel and second drain channel) with independent flow paths. Each channel has its own piston (first piston and second piston) that can be independently controlled, allowing uniform volume flow distribution to the two hydrostatic pockets while reducing pressure losses through optimized flow paths.
Solution Approach 2:
A double piston mechanism with a centre member acts as an intermediary between the two drain channels. The centre member with its specific length (L ≥ 2d) mediates the flow distribution by ensuring that when the roll pin is inclined, both pistons move symmetrically to maintain equal opening cross-sections in both drain channels, achieving uniform volume flow distribution.
2Reliability
If throttles or restrictors are used in the bores, then hydrostatic journalling is achieved, but uniform volume flow distribution to two hydrostatic pockets is not achieved, especially when the roll pin is inclined
Solution Approach 1:
The double piston design inherently accommodates asymmetric conditions (inclined roll pin) through its symmetric structure. When the roll pin tilts, the asymmetric load distribution is converted into symmetric piston movements via the centre member, which translates the inclined position into equal opening cross-sections in both drain channels, ensuring uniform volume flow distribution despite the asymmetric operating condition.
Solution Approach 2:
The opening cross-sections of the drain channels are dynamically changed through piston displacement. The centre member length (L ≥ 2d) ensures that piston displacement due to roll pin inclination results in equal opening cross-sections in both channels, automatically adjusting the flow parameters to maintain uniform volume flow distribution under varying operating conditions.
3Manufacturing precision
If a centre member with length L ≥ 2d is used in the double piston, then equal opening cross-sections are ensured in drain channels during inclined settings, but the device complexity increases
Solution Approach 1:
Two pistons are merged into a single double piston structure connected by a centre member. This combination ensures that both pistons move symmetrically and maintain equal opening cross-sections in the drain channels. The merged structure reduces the number of independent components while achieving the precision requirement for equal flow distribution.
Solution Approach 2:
The centre member with length L ≥ 2d creates a geometric relationship that ensures equipotential conditions for flow distribution. When the roll pin is inclined, the centre member translates the displacement into equal opening cross-sections in both drain channels, maintaining equipotential flow conditions that result in uniform volume flow distribution to both hydrostatic pockets.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures uniform volume flow distribution in both drain channels even under different pressure ratios, reducing pressure losses and maintaining consistent flow during oblique roll pin settings, suitable for pressures up to 2,000 bars.
Implementation Method 1
A first piston and a second piston are provided, which are fixedly connected together by way of a centre member... the first and second pistons are each closed by the first and second drain channels to an equal extent
Implementation Method 2
A spring is arranged in the interior of the cavity... which holds the double piston in a centre setting
Data Source
AI summary
A volume flow regulating valve for controlling the volume flow of a fluid medium in two outflow ducts. The volume flow regulating valve is composed of a cylinder with a dual piston mounted axially displaceably in the cylinder, with a central pressure chamber being formed in the region of the barbell-shaped central piece of the dual piston. Aside from an inlet for the fluid medium, it is also the case that the two outlet ducts are provided at the central pressure chamber. The outlet ducts are arranged on the cylinder with such an axial spacing that—when the dual piston is situated in a central position in relation to the two outlet ducts—the first outlet duct—preferably partially covered by the first piston—and the second outlet duct—preferably partially covered by the second piston—each open up an equal opening cross-sectional area.