The Control Valve Handbook has been a primary reference since its first printing in. Control Valve Handbook | Table of Contents . Valve Sizing. This valve sizing software program is based on the use 1. Masoneilan Control Valve Sizing .. Note: Within this control valve handbook, the metric factors. Masoneilan Control Valve Sizing Handbook – Download as PDF File .pdf), Text File .txt) or read online.
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Values are averaged and may vary. While the dollar cost is of great importance handnook a user, the Instrumentation Engineers, as automatic control specialists, are primarily interested in valve size from the engineering point of view as summarized in 2 above.
In masoneilab procedure, the numbers in the equations consist of values for the fluid and flow conditions and known values for the selected valve at rated opening. Consequently, rangeability and contrll at low flow conditions are lost. Such a procedure can tend to produce some oversized valve installations, unless much care is exercised. An almost universal approach to valve sizing today is through the Cv factor method.
Size Upper Travel in. The equal percentage curve provides a characteristic distorted less by line pressure losses which rob the valve of pressure drop. When the plug throttles very close to the seat, high fluid velocities occur which can cause erosive damage. The principal use of the equations handboom to aid in the selection of an appropriate valve size for a specific application.
Minimum valve pressure drop at full flow is occasionally estimated without thorough analysis, and such estimates are often much too low. Control Valve Tuning Handbook Masoneilan handbook for control valve sizing. One must constantly remember that pressure drop which is to occur in the control valve plays almost as prominent a part as flow rate. Is it not logical, then, to study the proposed operating conditions with the object of selecting realistic pressure drops from careful engineering surveys of all factors that can affect the proposed valve?
MASONEILAN () Control Valve Sizing Handbook
The equations are not intended for use when dense slurries, dry solids or non-Newtonian liquids are encountered. The end result is the selection of an oversized equal percentage valve that operates in the low portions of lift even at maximum flow.
A misapplied linear valve exhibits the opposite effect. Many control valve specifications are written which give questionable pressure drops. With these factors in the equation, the unknown or conttol of the unknowns, e. Download the Fisher control valve Masoneilan Control Valve Handbook the Fisher control valve handbook: Body Size Inlet x Outlet in.
Although these computed numbers are often suitable for selecting a valve from a series of discrete sizes, they do not represent a true hadnbook condition. A controller properly adjusted at the high flow rate has too narrow a proportional band setting for stability at low flows. Cv values shown are based on ideal flow characteristics. In practice, the gain can and does vary from the theoretical. In Europe, the Kv and Av coefficients are more widely used.
This is important because a serious mismatch might cause the system to be unstable and difficult to control effectively.
By experience, some engineers feel confident in placing their normal operating strokes at a certain fraction of full stem travel. See page 30 for valve size 6″”. For example, referring a valve wilt a rated Cv of Cv is a capacity rating coefficient which is defined as the number of U.
Masoneilan Control Valve Sizing Handbook Supplement
Additional explanations and supportive information are provided beyond the content of the standards. Masoneilan Control Valve Sizing Manual – firv3.
Published on Nov View Download 6. Although in this example the flow increments are identical, in practice, these values can and do vary from the theoretical.
Concentration, as measured by analysis such as pH, is best controlled by a valve with an equal percentage characteristic When the ratio of maximum to minimum valve pressure drop at full flow is greater than 2 to 1. To do this, all the pertinent coontrol factors must be known at fractional valve openings.
Masoneilan Control Valve Sizing Handbook Supplement 1995-08
This tabulation supersedes all previous listings since many changes were requiered to bring all ratings in line with actual test data taking into account the use of the critical flow factor, Cf. The formulas in the early chapters controk set up in sections to simplify manual calculation for the more common control valve sizing problems.
A computer sizing program having this information in a database can perform this task. They seem satisfied if the listed Cv factor is something in cotrol of their maximum Cv as increased cntrol the computed normal.
They are the dynamic response of the process and the combination of transmitter and primary device. Some of the factors are for the valve at rated travel, while others relating to the operating conditions are for the partially open valve.
This variation in where most of the total drop takes place is one of the most important aspects in choosing the proper valve characteristic for a given process.