Orifice flowmeter installation:
Pressure sensing hole-Connect the upstream and downstream pressure holes of the orifice plate and the differential pressure transmitter through an induction tube (also called a pulse tube). The most commonly used pressure sensing holes are:
Take pressure from flange (or orifice mounting). This is the most common way of taking pressure, but when the pressure port is at the bottom of the pipe, special attention is needed, because it may be blocked at the bottom. 1 times the pipe diameter in front of the orifice plate and 0.5 times the pipe diameter in the rear. This method is relatively difficult, but more accurate, because the maximum differential pressure is at the contraction section of the fluid, that is, at 0.5 times the pipe diameter. Angular connection pressure-this method is usually used on the orifice plate with a small diameter. Because of space constraints, it is difficult to machine pressure holes on the flange. Angular joint pressure extraction method is generally used in the case of pipeline diameter less than or equal to DN50. The signal generated by the differential pressure transmitter can be output to the flow display, or input to the flow computer together with the temperature and pressure signals, so that the density of the fluid can be compensated. Pipeline-The minimum straight pipe section downstream of the orifice plate is required to be 5 times the pipe diameter to reduce the change in flow velocity distribution due to the pipe effect.