Control Valve: Guide To Control Valve Selection
More and more industries are looking for better results, demanding the improvement of installations; the controls must be increasingly strict. Thus, an element is essential to guarantee the stable system, responding to the need for controls, avoiding deviations, and ensuring the final process’s guarantee.
In this post, we will be talking about one of the elements that play a fundamental role or learn more on website: the control valves. These are the final elements of a control loop that must perform excellently because they are responsible for increasing the profitability of the process plant and conserving energy.
In this way, the correct selection of the valve determines a significant result on the general costs of your project, being assertive in the control of the process in question, thus ensuring a significant financial result. For this reason, we must pay the utmost attention to “VALVE SELECTION” for the process.
“To narrow down the options, the engineer must understand how the general characteristics of each valve type match the valve design requirements.”
As already mentioned in a process, our greatest intention is to know (measure) and control the variables that exist in our process; for that, you need to use instruments and devices that allow us to feel the physical or chemical variable that we want to know about this “sensor” instrument. As your interest in most situations is to control this variable, you will need a device that continuously monitors the values ”felt” by the sensor and compares with the value you want to keep under control; for this, you need to control the energies that are involved to these systems, in this case, you will be presenting the last element called the final element of the control.
This process of sensing the variable compares this signal with the set value and makes the necessary corrections through a signal sent to a control valve. Once the final element has been adjusted, the signal becomes beautiful again through the sensor, and the loop is completed. This set of elements working in harmony is called the “Closed Control Loop.”
Basic Conditions For A High-Performance Valve
Have good rangeability allowing to work with variable flows
Respond with precision and repeatability in various operating ranges;
Respond to the process faster (short time possible)
Comply with the resolutions of the values sent by the controller.
Have an adequate response to the process according to the control characteristics.
Note: A response that does not meet the process can cause significant damage and may generate risks of accidents.
For example, a sudden or rapid reduction in the diameter of a valve in a pipeline can be harmful, causing a shock wave (water hammer, water hammer), such as in a water injection line in an oil pipeline. Therefore, when specifying a valve, a valve’s ability to control the flow depends not only on the characteristics of the valve trim but also on its peripherals such as actuators and positioners and all accessories used in the valve.
Among the most common accessories in control valves, we can highlight the positioner; this component allows the correct positioning in the valve position, thus allowing for more rigid control, considerably improving the performance of the valve in the control mesh, ensuring the perfect positioning of the valve to get more accurate answers. With the use of the positioner, it is possible to prevent effects such as friction existing when opening and closing the valve, which can affect the operation of the valve (opening and closing); currently, with the development of technology, we can increasingly obtain productive information on the operation of the valve using smart positioners. Visit website to learn more.