Importance of Proper Control Valve Sizing
The flow coefficient of a control valve (Cv) is a numerical value expressing the number of gallons per minute flow of water the valve will pass with a constant pressure…
Total Organic Carbon Analyzer Principle
TOC analyzer Introduction of organic matter into water system occur only from living organisms and from decaying matter in source water, but also from purification and distribution system’s materials. In…
Coriolis Flow Meter Construction
Coriolis flow meter design uses a U shaped tube that redirects the fluid flow back to the center of rotation. See Coriolis Flow Meter Construction Images.
Basics of Control Valve Sizing
When control valves operate between fully open and fully shut, they serve much the same purpose in process systems as resistors do in electric circuits: to dissipate energy. Like resistors,…
Control Valve Split Range Example
As an example of a split-ranged system with opposite valve failure modes, consider the following temperature control system supplying either hot water or chilled water to a “jacket” surrounding a…
Control Valve Sequence Methods
In Control Valve Sequencing, for example, both control valves received the same pneumatic signal from a common I/P (current-to-pressure) converter. This means each valve received the exact same pressure signal…
Progressive Control Valve Sequence
Another form of control valve sequencing is used to expand the operating range of flow control for some fluid beyond that which a single control valve could muster. Once again…
Exclusive Control Valve Sequence
Other applications for split-ranged control valves call for a form of valve sequencing where both valves are fully closed at a 50% controller output signal, with one valve opening fully…
Complementary Control Valve Sequence
The first type of control valve sequencing is a mode where two valves serve to proportion a mixture of two fluid streams, such as this example where base and pigment…
Control Valve Positioners
The reason why a pneumatic control valve’s stem position corresponds linearly to the amount of air pressure applied to the actuator is because mechanical springs tend to follow Hooke’s Law,…
