In the process of automatic control system, the control valve is an important and indispensable link, which is called the production process automation "hands and feet", is one of the terminal control components of the automatic control system.
Flow control valve is simple, small resistance, under normal circumstances is suitable for the use. However, in the high pressure reducing valve reverse use, in order to improve the imbalance force and reduce the damage to the spool, but also conducive to the flow of media, to prevent the valve coking and clogging. Control valve used in reverse, in particular should be avoided for a long time to open the case of small opening to prevent damage caused by the strong oscillation valve. Due to the lower trial, the design process conditions can quickly meet the requirements, the use of reverse valve should be avoided for a longer time to open a small opening status, to prevent damage to the valve.
Regulating valve is composed of two parts of the actuator and valve. From the hydraulic point of view, the control valve is a local resistance can change the throttle element, the valve is in accordance with the input signal by changing the stroke to change the drag coefficient, so as to achieve the purpose of regulating the flow.
Structure and use
1 regulating valve structure
Except for the angle, the other structures of single seat valve are similar, characterized by the decision of its flow path is simple, low resistance, especially to adjust the pressure drop, high viscosity, suspended solids and granular materials containing fluid. The utility model can avoid the phenomenon of coking, sticking and blocking, and is convenient for cleaning and self purification.
2 positive and negative control valve comparison
Under normal circumstances, the valve is used to install the positive, that is, into the side of the bottom. Only in the case of high pressure difference and high viscosity, easy to coke, containing suspended particulate matter in the case, it is recommended that the reverse installation, that is, the material side into the bottom out. The purpose of the reverse use of the valve is to improve the unbalanced force and reduce the wear of the spool, but also conducive to high viscosity, easy to coke and suspended particles containing medium flow, to avoid coking and clogging.
Reverse usage analysis
Control valve in the process of high pressure drop, recommended reverse use. In the test, the control valve produced a strong oscillation, and issued a harsh noise, after the commissioning of the spool 4h broken. But this is not a quality problem, but due to the use of unreasonable.
In addition to the butterfly valve and diaphragm valve in the structure is completely symmetrical, all other structures are asymmetric valves. The normal flow of various types of regulating valves are to open the spool direction, the production plant also provides only the normal flow of the flow capacity) value and flow characteristics. Water linkage test, the simulation conditions can quickly reach the normal state, the valve in the small opening under the use in a long time, because the role of unbalanced force, there will be serious instability. Therefore, the control valve will produce a strong shock and a harsh noise, resulting in rapid fracture spool. In normal conditions, the control valve opening is moderate, even a small opening is short, so the normal safety valve can be used.
Under normal circumstances, the control valve is not recommended to use the reverse, only in the high-pressure differential, high viscosity, easy to coke and suspended particles containing medium is recommended reverse use. Reverse use, should avoid prolonged case of small opening run, especially when the test should pay attention.
For more information about sanitary valves, please visit http://www.adamantvalves.com/sanitary-regulating-valves.html