Apr 10, 2018

Teaching an Old Valve New Tricks

Retrofitting existing control valves with new automation technology

Ryan Spooner writes on retrofitting old valves with automation technology

Everywhere around us, networks of water systems are storing, controlling and moving water from one place to another. However, with every twist and turn of water through these distribution networks, the risk of water loss increases. These losses accelerate with aging infrastructure, over-pressurized systems and lack of maintenance. 

For years, water management systems have exclusively used mechanical components.  However, recently there has been a push to develop better methods for controlling water and having external interaction with the system. Reducing maintenance, saving water and reducing pipe breakage through remote control are the aims of these solutions. By adding instrumentation and automation to existing systems, users can gain control over an entire system. Instrumentation, such as flowmeters and pressure transmitters, give real-time data of a system’s current working condition. By adding automation tools such as control panels and supervisory control and data acquisition (SCADA) integration, users can also manipulate and control the system. For example, to reduce pressures in a system during off-peak hours, users can establish a sequence of control outcomes through SCADA to automatically throttle back the system. This is a simple step that can produce major cost savings. 

By reducing pressure when demand is low, utilities can realize significant declines in water loss, as well as less pressure stress on the system, which reduces pipe breakages and leaks.

Singer_Model_106_2_SC_PCO_Control_Valve_after_retrofit_copy MCP_TP_Field_Wiring_Connection_SCADA_Ethernet_Connection_copy

Top: Instrumentation tools such as flowmeters and pressure transmitters can provide real-time data on a system’s working condition.

Bottom: Control panels can control valves to the user’s selected level to ensure the correct levels are always maintained.

Bringing the System Online 

The City of Sheridan, Wyo., wanted to add automation and instrumentation to bring part of its system online. This would allow for more control over its water system while implementing system redundancy. The system is fed from two water sources, which can be treated at two different water treatment plants and then distributed to the public. Different storage tanks also are utilized through the distribution system.

The city identified an opportunity to repurpose an existing pressure-reducing valve so it could leverage gravity flow from an upstream treatment plant to fill a water storage tank. By reconfiguring the valve operation with instrumentation and automation (in combination with a realignment of buried valves in the yard), it could bring this otherwise hidden valve live into the system. The project would save power, as it would not need to use the booster station to fill the tank; however, it could remain as a redundancy when needed. Having two options to fill the tank means the city can use real-time data to choose to run either option as best suited. The new automation will enable this to be done remotely from the control room at the head office. 

The existing Singer Model 106-PR was repurposed to a Model 106-2SC-PCO. The current valve now has the capacity to interact and be controlled by a control panel via new valve-mounted solenoids that replaced the hydraulic-controlled mechanical pilots. An electronic valve position indicator and differential pressure transmitter also were added to the valve. To control the new reconfigured valve for both flow and level control, a Singer industrial MCP-TP control panel was added. The control panel uses the feedback from the valve position transmitter and differential pressure transmitter to calculate the current flow through the valve. The level sensor at the water tank measures the current water level and sends that feedback to the control panel. With all the instrumentation data feeding back to the MCP-TP, the control panel can now control the valve to ensure the user set level in the tank is always maintained. 

To ensure over-drafting of water from the upstream system is not an issue, the control panel also takes into account the flow rate and ensures it maintains the user-set flow rate while filling the tank. The user-set flow rate can be adjusted to ensure the tank is filling fast enough while not over-drafting the system. The flow and level set points can be changed and manipulated at any time to optimize operation of the system.

The user-chosen set points for tank level and flow rate are set locally at the MCP-TP control panel via a touch-screen display, or via the SCADA control network. The control panel was integrated into the city’s existing network using Ethernet communication. This allows remote access to the site from the main control room to view and control the current flow, level, valve position, current alarms and control modes, and it gives easy access to set all the control set points. Essentially, the integration gave the control room the same access as if the users were standing right in front of the MCP-TP control panel pushing the touch-screen buttons on the human-machine interface. 

Singer’s staff, along with Jacob McGough, application engineering and sales representative for Pipestone Equipment, finalized the commissioning of the project on site. This included full setup of all the instrumentation and testing of the control sequences of the MCP-TP panel and its control of the valve. The final steps were concluded when the system went live and the city of Sheridan operators could test all the SCADA controls and fully control the new system. 

“I was really happy with the support we got with field programming coordination and follow ups. It was above and beyond our expectations and solidified our confidence in the system,” said Marcus Weaver, system integrator and electrical technician. 

Security & Reliability

This means the people of Sheridan now have another layer of security and dependability on this part of their water supply system, while saving on pumping costs. For the operators of Sheridan’s water system, it means less time spent in the field monitoring and managing flow requirements.  

“This valve helps us operate, monitor and diagnose our water system remotely and in real time,” said Ken Hirschman, utility maintenance superintendent for Sheridan. “I am excited to see this technology expanded into our other existing infrastructure so that we can monitor how our pressure zones are operating remotely by using our existing SCADA system. These types of electronic operations and monitoring are all important steps in moving toward a smart and efficient utility.”

McGough said the market for these systems is rapidly growing. 

“Currently, 25% of our sales in the hydraulic control valve market [are] being offered with electronic capabilities. This percentage has been on the rise over the last couple of years as more people are introduced to the vast improvements of these types of solutions for mitigating non‐revenue water loss and resolving aging infrastructure problems,” McGough said.

In today’s world, there often is a tendency to view things as disposable and simply replace the old with the new. This is not always necessary. Sometimes a simple upgrade can bring on a whole new world of possibilities. Instrumentation and automation can streamline operations and significantly reduce costs with a smaller expense than complete replacement.

About the author

Ryan Spooner is automation & instrumentation engineering manager for Mueller Water Products. Spooner can be reached at [email protected]

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