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What is Wastewater, and How is it Treated?

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?”

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Control Valve Trim Styles and Flow Characteristics

Hi-Flow™ Valve Cutaway

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”

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Control Valve Actuator Sizing and Valve Action Selection

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.

Hi-Flow™ 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”