By Jeff Sines, Engineered Software, Inc.
The over-controlled message in PIPE-FLO® Professional has historically been difficult for users to understand and reconcile. Improvements being made in PIPE-FLO® Professional Version 15 (due for release in September 2015) will address the conditions that cause this message. Due to the way PIPE-FLO® “sees” each device in its various operating modes, there are several piping system configurations that can cause the over-controlled condition.
An over-controlled condition is created when a user designs a piping system and a portion of the system is isolated from a pressure source, resulting in an infinite number of solutions that could satisfy the Conservation of Energy, so PIPE-FLO® cannot arrive at a single solution. Improvements include new messaging to identify the specific cause of the Over-controlled configuration, highlighting the affected sections, new modes of operation for pumps, and an automatic solution for some configurations involving pumps and control valves.
New Messages and Highlighting of Over-controlled Sections
The single message (ID 104) displayed in previous versions of PIPE-FLO® is being replaced with individual messages that identify the exact cause of the Over-controlled configuration. ID 180 will be displayed when two or more flow control devices are configured in series, ID 181 will identify dead-ended pipes, and finally, improperly isolating a flow control device will generate ID 182. All three messages are Level 0 messages that prevent calculations from being performed.
Along with the new messages, the section that is over-controlled and isolated from a pressure source will be highlighted to allow easy identification of the devices that may be contributing to the problem. Figure 1 shows an over-controlled section highlighted and the devices that are involved.
Figure 1. New highlighting shown in an over-controlled section with a valve in PRV mode.