g = K dnz .f in .NET

Generator QR Code ISO/IEC18004 in .NET g = K dnz .f

g = K dnz .f
QR Code Recognizer In .NET
Using Barcode Control SDK for Visual Studio .NET Control to generate, create, read, scan barcode image in .NET framework applications.
Denso QR Bar Code Generation In .NET Framework
Using Barcode drawer for VS .NET Control to generate, create Quick Response Code image in Visual Studio .NET applications.
(2.10)
Scanning QR-Code In .NET
Using Barcode scanner for VS .NET Control to read, scan read, scan image in .NET applications.
Barcode Generation In .NET
Using Barcode maker for .NET Control to generate, create bar code image in .NET applications.
where FU = fractional stem position K = constant This constant for a typical equal-percentage valve is about 4. The dimensionless gain of the valve then becomes df - = 4J dm Combining this wit h the maximum rated flow of the valve yields G, = 4f maximum flow 100% (2.12) (2.11)
Bar Code Decoder In .NET Framework
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
Draw QR Code In Visual C#.NET
Using Barcode maker for .NET Control to generate, create QR Code image in Visual Studio .NET applications.
The equal-percentage characterist,ic has an interesting feature: changing the valve size does not affect the loop gain! Fractional flow 1 times the maximum flow equals the actual flow being delivered. The valve
QR Code Creator In .NET Framework
Using Barcode creation for ASP.NET Control to generate, create QR Code image in ASP.NET applications.
Quick Response Code Maker In VB.NET
Using Barcode drawer for VS .NET Control to generate, create Denso QR Bar Code image in .NET framework applications.
n Ud erstanding Feedback Control
EAN13 Encoder In .NET Framework
Using Barcode generator for .NET Control to generate, create EAN 13 image in .NET applications.
Make Matrix 2D Barcode In Visual Studio .NET
Using Barcode printer for .NET Control to generate, create Matrix Barcode image in VS .NET applications.
FIG 2.6. The gain of an equal-percentage valve is directly proportional to flow.
Encoding Barcode In .NET Framework
Using Barcode printer for .NET Control to generate, create barcode image in .NET framework applications.
Ames Code Drawer In Visual Studio .NET
Using Barcode maker for Visual Studio .NET Control to generate, create Monarch image in .NET framework applications.
gain is consequently a function of the actual flow and has nothing to do with valve size. This is one reason why equal-percentage valves are used extensively-valve sizing is not critical. Sometimes this valve characteristic is shown as a straight line on semilogarithmic coordinates. Integration of the differential expression for valve gain does yield the logarithmic expression - 1nJr = 4(1 - 972) (2.13) Other common valve types include the quick-opening (globe) and the butterfly. Their characteristics are more a result of accident than design. III other words, the nature of their construction is the reason for their characteristics, not vice versa. They will generally be employed regardless of, not because of, their nonlinearity.
EAN128 Scanner In Visual C#
Using Barcode recognizer for .NET Control to read, scan read, scan image in VS .NET applications.
Paint Data Matrix In None
Using Barcode drawer for Microsoft Word Control to generate, create Data Matrix image in Word applications.
FIG 2.7. Characteristics of quickopening and butterfly valves.
GS1 RSS Printer In Java
Using Barcode creator for Java Control to generate, create GS1 DataBar Expanded image in Java applications.
ECC200 Creator In .NET Framework
Using Barcode creation for Reporting Service Control to generate, create DataMatrix image in Reporting Service applications.
Characteristics of Real Processes
Code 3/9 Maker In Java
Using Barcode generator for Java Control to generate, create Code 39 Extended image in Java applications.
Create Code 3/9 In None
Using Barcode drawer for Excel Control to generate, create Code 39 image in Microsoft Excel applications.
Variable Pressure Drop
Linear 1D Barcode Maker In Visual C#
Using Barcode printer for Visual Studio .NET Control to generate, create Linear Barcode image in .NET framework applications.
ECC200 Generation In None
Using Barcode generation for Software Control to generate, create DataMatrix image in Software applications.
The equal-percentage valve was intentionally devised to compensate for gain variations elsewhere in the control loop. The nearest source of variable gain is t,he pressure loss in piping and fittings in series with the valve. The flow of liquid which a valve can deliver is as much a function of available pressure as it is of valve opening:
F = c,
G-J -\: T
where C,. = flow coefficient of valve Ap = drop across valve p = specific gravity of flowing fluid Should Ap change, F will also change. Choice of the valve is therefore intimately connected with t he associated piping and motive force for the fluid. If Ap is constant, the valve will exhibit its inherent characteristic, but if Ap varies with flow, the relation between flow and stroke will change. Figure 2.8 typifies an arrangement where a constant pressure source drives fluid through a fixed resistance whose flow coefficient is CR and through a valve of variable resistance whose flow coefficient is C,. into a sink of constant pressure. As flow approaches zero, the valve will be nearly closed and the entire pressure drop in the system will exist across the valve. But at maximum flow, particularly if CR is less than C,., the drop across the valve will be reduced markedly. If the valve is linear, the gain of the system will be high at low rates of flow (high hp) and low at, high rates (low Ap). Since the gain of the valve has been defined as flow in response to stem position, the gain of the valve is affected by variable pressure drop. If we consider a liquid of specific gravity 1.0, F* = C,*(PI - PZ) =
C2(po
- PI)
Eliminating the variable pressure p,,
Let C,, represent the maximum valve opening. Then, if the valve is linear, its opening will be UHZ,, where 111 is the fractional stem position.
FIG 2.8. Pressure drop across the control valve depends on losses through the series resistance.
Source
Sink
50 1.0
n 1 Ud erstanding Feedback Control
FIG 2.9. Line resistance distorts a linear characteristic toward that of a quick-opening ualve.
OY1.0
If we include stem position in the above,
where J = fractional flow F = maximum flow Fractional flow can be related to stem position by extracting the square root of the ratio of the last two equations:
(c,/c,>2 s = I(c,./c,)2 + +l/m1 2 I $4
(2.15)
A plot of J vs. 712 for various ratios of C,./Clt appears in Fig. 2.9. The effect of an equal-percentage characteristic upon the nonlinearity of line drop can be seen by combining these curves with the curves in
f 0.5
FIG 2.10. An equal-percentage valve is able to remove most of the effect of line drop.
00.5 1.0
Characteristics of Real Processes
Ii PO 5 D E a
FIG 2.11. Discharge pressure from a centrifugal pump varies with the flow being delivered.
$ i :: 0
Copyright © OnBarcode.com . All rights reserved.