Control valves are used to change process conditions such as flow, temperature, level, and pH. A complete control system would include a sensor, controller, positioner or current to pressure transducer, and control valve. Globe valves, such as the Dwyer Hi-Flow™ Series, are a common type of control valve. In the example shown, a Hi-Flow™ control valve is controlling temperature by varying the amount of steam or cold water added to the process. Continue reading “Control Valve Sizing”
Every day, billions of gallons of wastewater are collected from our homes, businesses, and industries. Wastewater is exactly what it sounds like: water that has already been used and disposed of via a tub, toilet, sink, or storm drains. Because it is full of contaminants that make the water no longer suitable for use, it is collected in the sewer system and delivered to plants for treatment to make the water safe to be returned to the environment. Continue reading “What is Wastewater, and How is it Treated?”
A hydronic system is a system designed to circulate chilled or hot water with the connections between piping and terminal units (heating and/or cooling devices). Most hydronic systems are closed and are usually made in a series loop. In addition to pipes and terminals, valves are placed in this series as a port to balance the differential pressure in the system. The balance of this type of system is often referred to as hydronic or hydraulic balancing. Continue reading “What is a Hydronic System and What is Needed to Balance it?”
Hi-Flow™ Control Valves vary the flow in a system by throttling the valve plug in and out of the valve seat. The corresponding flow rate through the valve is based on the valve plug and seat type, which is part of the valve trim. Dwyer Instruments, Inc. offers several flow characteristics, needle plugs, and restricted trim options for the Hi-Flow™ Control Valve series.
There are two types of inherent flow characteristic trim styles available in the Hi-Flow™ product line: Linear and Equal percentage. Continue reading “Control Valve Trim Styles and Flow Characteristics”
Control valves are used to change process conditions such as flow, temperature, level, and pH. A complete control system would include: a sensor, controller, positioner or current to pressure transducer, and control valve. Globe valves, such as the Dwyer Series 2000VA/ 3000WA Hi-Flow™ Control Valve, are a very common type of control valve.
The Dwyer Hi-Flow™ Series control valves have pneumatic actuators that modulate the valve for flow control. The opening, closing and throttling of the valve plug is accomplished by varying the air pressure to the diaphragm in the actuator. Typically the control pressure signal is 3 to 15 psig. There are two types of actuators: Air-To-Lower and Air-To- Raise. Continue reading “Control Valve Actuator Sizing and Valve Action Selection”