Bulletin #:002_05

Date:02-25-2005

Category:2

Subject:User Valve Data Warning Messages

Program affected:PIPE-FLO Professinoal and Lite (2004) and PIPE-FLO Stock (2005)

Approved by:CP

Background

Control valve operation can be modeled by importing valve catalog data from electronic catalogs. If users do not have an electronic valve catalog, they can manually enter the valve data.

Fl is the Liquid pressure recovery factor – it is required for the valve calculations when the fluid upstream of the valve is a liquid. Xt is the pressure drop ratio factor – it is required for the valve calculations when the fluid upstream of the valve is a gas. If a valve is entered with only Xt coefficients, the program marks the valve as a "gas only" valve and will stop the calculation and issue an error message if the upstream fluid zone is a liquid. Similarly, if a valve is entered with only Fl coefficients, the program marks the valve as "liquid only" and will stop the calculation and issue an error message if the upstream fluid zone is a gas.

Condition

A condition has been identified in which PIPE-FLO incorrectly identifies valves as "liquid only" or "gas only." If a valve is initially entered without Fl coefficients and saved, then later edited and the Fl coefficients added, PIPE-FLO still considers the valve to be a "gas only" valve. The same is true for valves that are initially entered without Xt data – editing the valve later and adding Xt coefficients does not change the valve's "liquid only" status.

Workaround

If this situation occurs for a valve in you have installed in your model, delete the valve and reinstall it. When entering the valve data, specify both the Fl and Xt coefficients (or make sure you specify the coefficients that are required for the fluid conditions upstream of the valve).

This problem will be corrected in the next release of PIPE-FLO.