Does a flow restriction orifice plate belong to a flow meter?

It does not belong to this category; the flow restriction orifice plate is a concentric sharp-orifice plate that is primarily used to limit the flow rate of a fluid or reduce its pressure. I’ve looked up some information; I hope it will be helpful to you. 1. Ensuring the safe startup and proper operation of the centrifugal pump: To ensure that the centrifugal pump starts safely and operates properly, it is necessary for the pump to have a minimum discharge flow rate; this value is known as the pump’s minimum flow rate. Typically, the minimum flow rate is specified by the pump manufacturer. To ensure a minimum flow rate, a return line is added to the outlet pipeline of the centrifugal pump, known as the minimum flow line. By using a flow-limiting orifice plate on the minimum flow line, it is possible to ensure the safe operation of the centrifugal pump, even in the event that the pump’s outlet valve is closed by mistake, thereby preventing damage to the pump. 2. Using a flow-limiting orifice plate to set the maximum flow rate. In process operations where there is no need to adjust the flow rate, but only a limitation on the maximum flow rate is required, a flow-limiting orifice plate can be used in place of a flow control circuit to prevent excessive flow and thus save on investment costs. This is also one of the most common uses of flow restriction orifice plates. 3. Prevent uneven flow in various branch pipes: Under certain conditions, the process requires that the flow rate in each branch pipe be the same. However, since it is difficult for the pressure drops in each branch pipe to be exactly equal, there are differences in their flow rates. Using flow-limiting orifice plates allows the pressure drop in each branch to be adjusted, thereby maintaining a consistent flow rate in all branches

Agree with what was said above. As a supplementary note: we also use flow-limiting orifice plates (with an aperture of 1–1.5 mm) in the backblast pipeline of our catalytic unit. The purpose is: low flow rate, high pressure, and easy control. In other words, it is necessary to maintain a low flow rate that remains constant under unchanged pressure.

Throttling orifice plates do not belong, while measuring orifice plates do.

However, in terms of procurement, the flow control orifice plate falls under the category of instrumentation pipes; I’m not sure how your factories classify it

Procurement falls under instruments. The original poster was simply asking whether a flow restriction orifice plate is a type of flow meter; they didn’t say it isn’t a meter. It’s a bit tricky to say, hehe

The flow restriction orifice plate is designed by the process engineering department, not by the instrumentation department.

Although it doesn’t belong to category 1, the design calculations are based on orifice plate flowmeters