Does the flow meter have a switch function?
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The functions of the flow meter selected here are as follows: it is installed in the feed pipe and allows for setting the feed volume (which can be done via DCS or a controller). Some have suggested that a vortex flow meter combined with a controller (or a set value defined in the DCS in the remote control room) would be sufficient. Since I don’t have much knowledge about flow meters, I wonder whether it is necessary to install a switch valve that is activated by the signal from the flow meter Does the flow meter have a switch function? I’d like to ask everyone for advice
Ordinary flow meters do not have a switch function; those that do possess such a function are called flow switches. They can transmit the flow meter’s signal to control devices such as DCS or trip amplifiers, which in turn control the opening and closing of valves.
Agree with the opinion above; just doing it in DCS would be sufficient, right?
Does that flow switch have a metering function? Could we use only flow switches with a metering function, so that they can shut off at the set volume?
The signal position can be set to achieve a switching function
Generally, the switch signals for flow meters are sent by cumulative meters; these meters have normally open and normally closed contacts, and by making appropriate settings it is possible to control the opening and closing of valves
A flow switch outputs a switching signal based on the instantaneous flow rate (it generates a switching signal when the instantaneous flow rate is greater than or less than a set value); it cannot measure the flow rate accurately, nor does it have any function for flow accumulation； In the case of the original poster, the \"feed rate value\" should be a cumulative flow signal; therefore, one of the following two approaches should be used to control this \"feed rate value\": 1. Flow meter + DCS. The flow meter measures the instantaneous flow rate and sends it to the DCS; the DCS then calculates the cumulative flow rate. When this cumulative flow rate reaches a set value, it outputs a switch signal to control the opening and closing of the valve ； 2. Flow meter + integrator + controller. The flow meter measures the instantaneous flow rate and sends it to the integrator, which calculates the cumulative flow. When the cumulative flow reaches a set value, the integrator sends a switch signal to the controller, which then controls the opening and closing of the valve ； 3. Of course, some flow meters have the function of calculating cumulative flow, and they may also have the capability to set an alarm output for when the cumulative flow reaches a certain value (that is, they generate an alarm signal when this condition is met). This alarm signal can be sent directly to the controller, which in turn controls the opening and closing of the valve.