orifice meter daily check items are as follows: first, the orifice valve surface should be clean, no paint falls off, corrosion, the nameplate is clear, complete parts in good condition, no internal and external infiltrated phenomenon, flexible to use movable parts. Second, a monthly check for orifice valve operation, removal of orifice plate surface dirt, visual important parts of the orifice plate, if there are defects such as scratch, wear, corrosion pit, should be replaced, seal deformation must be replaced if there is any damage. Check the content mainly include: 2, 1) Appearance inspection: there should be no dirt, dust, corrosion of the orifice plate deformation and obvious damage. 2, 2) Measurement aperture: refers to the new orifice plate before using the aperture of measurement, method is to use 0. 02 level roughly equal Angle on the vernier caliper, round of four azimuth measurement, the result of arithmetic mean as the measured aperture value, this value should be consistent with marked the numerical aperture of orifice plate. 2, 3) Deformation inspection: use vernier caliper respectively abutting edge surface of the orifice, downstream face in vertical roughly two location, estimate the maximum crack width, the value and the measuring tube diameter ratio should be less than 0. 5%. 2, 4) Sharp degree of inspection: the inspection hole orifice plate on the edge of the rectangular entrance sharp degree, if find any visible defects such as scratches, erosion and abrasion, recommend replacing orifice. 2, 5) Pressure pipe cleaning: emptying of the monthly to the pressure pipe, purging, prevent pressure tube accumulate dirt. 2, 6) Three valve group check: check whether there is any leakage on five valve group of high and low pressure valve cavity, the valve closed root check zero has shift after balancing valve is opened.