Large-diameter carbon steel flanges have perforations on the flanges, which can be bolted so that the two flanges are tightly connected and the flanges are sealed with gaskets. When the large-diameter flange standard determines the flange size, the nominal diameter and nominal pressure of the flange must be known. There are holes in the carbon steel flange, which can be bolted so that the two flanges are tightly connected and the flanges are sealed with gaskets.
When the large-diameter flange standard determines the flange size, the nominal diameter and nominal pressure of the flange must be known. The nominal diameter of the pressure vessel flange is taken from the same series of values as the nominal diameter of the pressure vessel. For example, a DN1000mm pressure vessel should be equipped with a DN2000mm large diameter flange.
The determination of the nominal pressure of the large-diameter flange is related to the operating pressure of the flange, the operating temperature and the flange material. Because the flange size series is calculated and the flange thickness is calculated, it is based on the mechanical properties of 20MnR at 250 °C. Therefore, the flange size determined by this standard is specified. At 200 ° C, its allowable operating pressure is considered to be the nominal pressure of the flange of this size.
The flange under the combined action of bolt load and internal pressure produces deflection and warpage deformation, resulting in uneven stress distribution on the surface of the gasket. The radial stress is obviously tight inside and tight, and as the flange diameter increases, the unevenness becomes more and more obvious, and the hoop stress distribution is relatively uniform. It indicates that there is a problem of insufficient rigidity of the flange in the current standard, and the number of bolts is sufficient to ensure the uniformity of the circumferential stress distribution of the gasket. Among the three types of equipment flanges, the A-type flange is less rigid and can only be used in public places with lower pressure levels; the B-type flange cylinder is protected from additional bending moments caused by flange deformation and has higher rigidity. , adapt to larger size occasions; large diameter flange stiffness, can withstand higher pressure.
A large-diameter flange water meter characterized in that it comprises a water inlet flange, a gland fastening bolt and a cap, a cover, a case gland, a watch case, a water outlet flange, and a case cavity The rotor wheel and the deceleration metering mechanism have the same number of flange holes and the hole pitch of the water inlet and the water outlet. The invention has the following advantages: the phenomenon of stealing water by reverse connection of the water meter is completely solved.
There are many processing methods for large-diameter flanges. The processing methods are developed for different customers, and the method should be adopted for different materials during processing. The production process of the large-diameter flange is completely different from that of the small-diameter flange, because its caliber is too large, and it needs to be processed by docking or splicing during processing. Because the caliber of the production is different, the processing method is different. The processing method of the large flange is to select the processing method by the size determined by the customer.
Common flanges for large flanges have flat weld flanges and butt weld flanges. The flat welding flange has poor rigidity and is suitable for occasions with pressure p≤4MPa. The welded flange is also called high neck flange, which is relatively rigid and suitable for occasions with high pressure temperature.