Why we should give more thought to these versatile, durable valves
IN virtually every chemical plant and every chemical process there exists a need to divert process flow from one pipeline to another. This may be accomplished by multiple valving or it may be done through the use of diverter valves specifically designed for this purpose.
The requirement to divert flow from one process stream to another may be as simple as having the ability to maintain one stream in service while another is inspected and/or repaired. Or it may be as complex as switching from one polymer filter to another as one filter becomes dirty and the pressure drop increases, requiring a balance of pressures as one unit is taken out of service and another is brought on line with no interruption of process flow.
Process pumps are sometimes high maintenance items and are thus installed in parallel so that one may be serviced or repaired while the other carries the process load. With the use of a diverter valve, changing from one pump to another becomes an easy task with no process flow shutdown necessary.
Diverter valves can also be used as dump valves when there is a process upset. Normal process flow goes through one side of the valve while the other side is closed. When an upset occurs, the process side is closed, and the dump side is opened. Frequently the dump side is at right angles on both the process and dump side. Both may have pneumatic or hydraulic actuators for rapid response to a process upset.