Problems with the installation of flow restriction orifice plates
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Should the flow control orifice plate be installed in front of the manual valve or behind it? One theory is that the orifice plate in the pump’s minimum flow line is installed before the valve, while the orifice plate in the heat pump line is installed after the valve; I’m not sure if this is correct! Please, fellow sailors, explain the following!
The installation location of the flow control orifice plate usually depends on the system design and the functions to be achieved. If the goal is to protect the pump by preventing it from operating under low load, then the flow-limiting orifice plate should be installed in front of the manual valve, that is, on the side close to the pump. This ensures that the pump receives sufficient flow even when the manual valve is closed or partially closed. For heat pump pipelines, if the main objective is to control the flow rate into a specific area or device, an orifice plate should be installed behind the manual valve, thereby allowing for more precise control of the flow rate passing through the valve. Therefore, what you mentioned is correct. .
Check the medium flow direction; the valve is installed upstream of the orifice plate
However, most of the orifice plates on the minimum flow pipelines at the site are located in front of the valves
Throttle orifice plates are primarily used to limit the flow rate of a fluid and create a fixed pressure drop. When precise control of flow rate is required and the flow variation is small, a flow control orifice plate can be installed upstream or downstream of the valve. If installed upstream of the valve, the fluid passes through the orifice first, and its flow rate is initially restricted. At this point, the valve can be used to further adjust (such as fine-tune) the flow rate or to completely shut off the fluid flow. For example, in some chemical processing processes, to control the flow rate of the raw materials entering the reactor, a flow-limiting orifice plate is used first to ensure a basic flow range, followed by precise adjustment using valves. When installed downstream of a valve, the valve is primarily used to control whether fluid passes through and to determine the approximate flow rate range, while the flow restrictor plate provides more precise control over the flow rate of the fluid after it passes through the valve, keeping the flow rate at a specific value. For example, in the fluid supply systems of some analytical instruments that require extremely high precision regarding flow rates, valves are used to control the on/off flow of liquid as well as its approximate volume flow rate, while flow-limiting orifice plates ensure that the error in the flow rate of the liquid entering the instrument is minimal.