Issues with the szorb feed valve
Thread Content
From the raw material pump outlet of the szorb unit to the feed valve of the heating furnace, two control valves are arranged in parallel. I would like to know why two control valves are used in parallel here?
It should be step-by-step control; you can ask your process operator about it if you have the chance.
It’s not about dividing the process into stages; it’s just that there is a valve that is used when starting up the operation
One with a larger diameter and one with a smaller diameter?
That is, at the start of operation, if the flow rate is high, a larger valve is used; once normal conditions are reached and the flow rate decreases, a smaller valve is employed. The same explanation applies in reverse as well! This is a good practice! ! ! Great technical management! ! ! Not bad! ! !
Can’t large control valves achieve precise control of small flow rates?
The large control valve can certainly be adjusted, but since the flow rate has changed and decreased significantly, the opening degree of the control valve when controlled by the large valve becomes very small, falling outside the normal range. This can easily lead to cavitation in the control valve, **affecting its service life.
Can’t the control valves on the main pipelines regulate low flow rates either?
This minimum flow rate should be the most appropriate one for the process operation conditions; it cannot be reduced arbitrarily. Even if a control valve can be used to adjust it, such adjustment is only possible for a short period of time! Over time, the valve core and seat will inevitably wear out! The selection of a control valve is determined based on the process requirements, such as the maximum flow rate, normal flow rate, and minimum flow rate.
Setting two also takes into account process safety! Our gas pipeline is equipped with two control valves, one large and one small! The principle should be similar: use the smaller one when starting up, and the larger one for normal use!