When two orifice flanges are used together it is described in the industry as an orifice flange union. Each individual orifice flange comes with two pipe taps which are used for measuring the pressure drop of the flow through the orifice plate. Orifice plates donâ€™t actually come with flanges and they are sized depending on the process requirements. It is necessary to use two jack screws to spread the flanges apart so that the orifice plate can be changed.
An Orifice plate is a thin plate with a hole in the middle and it is placed in a pipe in which liquid flows. When the fluid reaches the orifice plate, the fluid goes through the small hole and the velocity and the pressure of the liquid changes. The liquid expands and the velocity and pressure changes again. If you measure the difference in liquid pressure between the normal pipe section and where it flows through the plate, the cliometric and mass flow rates can be calculated.Orifice flanges tend to be installed in a straight run of pipe so that turbulence can be avoided at the plate.
When you are installing the orifice plate flange the pressure taps need to be at the same height to each other. When making the calculation for the orifice plate, the static head of the tubes should be the same on both sides of the orifice plate. It is advised that pressure taps should not be installed facing down because the taps could potentially become plugged with debris in the line.