的连接方式孔板与取压孔整体加工，钻孔与孔板水平呈30°～45°角构成整体孔板。 Connection method of orifice plate flowmeter The orifice plate and the pressure taking hole are integrally processed, and the borehole and the orifice plate are horizontally formed at an angle of 30 ° ~ 45 ° to form an integral orifice plate. The two valves are combined with the pressure-receiving hole axis and welded to the positive and negative pressure-receiving ports of the orifice plate through a stainless steel short tube. The root valve is connected to the heat dissipation device through a pressure guiding tube (the heat dissipation device is provided with a drainage hole and a liquid injection hole), and then connected to the three valve group by a pressure guiding short tube and a joint, and the three valve group is connected to the orifice plate through the pillar. The other side of the three valve group is connected to a differential pressure transmitter and a pressure transmitter chamber (which can be independently equipped with pressure and temperature transmitters) to achieve differential pressure, pressure, and temperature measurement. Under special working conditions, it can be processed into butt welding type, pipe section flange type orifice plate as required
的组成孔板流量计是由一次检测件(节流件)和二次装置(差压变送器和流量显示仪)组成。 Orifice flowmeter composition Orifice flowmeter is composed of a primary detection (throttle) and a secondary device (differential pressure transmitter and flow indicator). It is composed of three parts: throttling device, differential pressure transmitter and flow indicator. The throttling device is mainly composed of a throttling member, a pressure taking device, a connection flange, and a measuring tube. Different types of throttles have different flowmeters: such as standard orifice plates, standard nozzles, long diameter nozzles, 1/4 round orifice plates, double orifice plates, eccentric orifice plates, round orifice plates, and tapered inlet orifice plates Wait. The pressure-receiving device is mainly composed of a ring chamber, a pressure-receiving flange, a clamping ring, and a pressure guiding tube. Connecting flanges (national standards, flanges of other standards and other design departments), fasteners. Then there are measuring tubes, differential pressure transmitters and flow indicators.
对安装管道条件 Orifice flowmeter for installation pipeline conditions
1. The straight pipe sections before and after the throttle must be straight, and there must be no visible bends. 2. The straight pipe section used to install the throttle should be smooth. If it is not smooth, the flow coefficient should be multiplied by the roughness to correct the sparseness. 3. In order to ensure that the fluid flow is 1D in front of the throttle, a fully developed turbulent velocity distribution is formed, and this distribution is uniformly axisymmetric, so:
1) The straight pipe section must be round, and for the 2D range in front of the throttle, its roundness requirements are very strict, and there is a certain roundness index. Specific measuring method: (A) OD, D / 2, D, 2D 4 vertical pipe sections in front of the throttling member, measure at least 4 single diameters of the inner diameter of the pipe at a maximum equal angular distance, and take the average value D. The difference between the single inner diameter measurement value and the average value must not exceed ± 0.3% (B) After the throttle, 8 inner diameter single measurement values are measured at the OD and 2D positions by the above method. Comparing any single measurement value with D, the The maximum deviation must not exceed ± 2%. 2) A sufficiently long straight pipe section is required before and after the throttle. This long straight pipe section is related to the form of the local resistance member in front of the throttle and the diameter ratio β. 3) The length of the straight pipe section between the first resistance member and the second resistance member on the upstream side of the throttling member can be 1/2 of the listed value according to the form of the second resistance member and β = 0.7 (regardless of the actual β value) 4. When the upstream side of the throttle is an open space or a large container with a diameter ≥ 2D, the length of the straight pipe between the open space or the large container and the throttle shall not be less than 30D (15D). If there are other local resistance parts between the throttle and the open space or the large container, in addition to the minimum straight pipe length 1 that meets the requirements between the throttle and the local resistance parts, from the open space to the The total length of the straight pipe sections between the flow pieces must not be less than 30D (15D). 5. Connect the signal and power lines. 6. Open the inlet and outlet valves. The inlet and outlet valve openings must be the same. 7. Open the stainless steel three-valve balance valve. Slowly open the valve at the high and low pressure end of the orifice plate and close it after the fluid passes the flow meter. Stainless steel three-valve balance valve