Standard plate (welding type) can be used to measure the liquid pipe, gas, steam flow. Standard orifice is based on GB GB / T2624-93 design and manufacturing, according to JJG640-94 examination. No real flow calibration. Standard orifice can be used corner tapping (including ring room to take pressure), flange pressure or DD / 2 Pressure three kinds of ways to take pressure. According to the national standard for the design, manufacture and test the standard orifice no real flow calibration, high precision, simple structure, low manufacturing costs, but the pressure losses. Standard orifice is widely used in petroleum, chemical, metallurgy, electric power and other industries. Is by far the most widely used one meter. Scope 1, nominal diameter: 50mm≤DN≤1200mm (beyond this range the case of non-standard throttling device) 2, PN: PN≤16MPa 3, the aperture ratio: 0.20≤β≤0.75 4, Reynolds Range: When 0.20≤ β≤0.45 when 5000≤ReD when 0.45≤β≤0.75 when 10000≤ReD 5, Accuracy: a structure requires an installation, the installation should ensure orifice center, center flange, pipe concentric center and gaskets, different heart shall not exceed 0.002D / β. 2, the positive and negative direction of the orifice, the pressure on the downstream flange should be taken in line with the medium flow, to take pressure hole orientation can be determined according to the different media and the installation of the transmitter. 3, when the throttle device is connected with the pipe, the pipe end and not perpendicular to the axis of the weld shall not be greater than 1 °, internal welds should be processed after the soldering process, making it smooth, no welding bar and weld slag. 4, take the pressure flange and pipe welding before, you should first take pressure holes drilled on the pipe, the same as the diameter of the aperture to take pressure on its flanges to take pressure, take pressure hole on the flange and the pipe pressure welding Pressure holes aligned. 5, optional belt, downstream straight pipe. 6, DD / 2 is a complete set of delivery to take pressure, flange connection can be installed directly.