是测量流量的差压发生装置，配合各种差压计或差压变送器可测量管道中各种流体的流量。 HN LG series orifice flowmeter is a differential pressure generating device for measuring flow rate. It can be used with various differential pressure gauges or differential pressure transmitters to measure the flow rate of various fluids in pipes. The orifice plate flow meter throttling device includes an annular chamber orifice plate, a nozzle and the like. Orifice flowmeter throttling device is used together with differential pressure transmitter to measure the flow of liquid, steam and gas. Orifice flowmeter is widely used in petroleum, chemical, metallurgy, power, light industry and other departments. The fluid filled with the pipeline, when they flow through the throttle device in the pipeline, the flow beam will form a local contraction at the throttle of the throttle device, thereby increasing the flow velocity and low static pressure, so it is generated before and after the throttle. The pressure drop, that is, the pressure difference, the greater the flow rate of the medium flow, the greater the pressure difference generated before and after the throttle, so the orifice flowmeter can measure the flow rate of the fluid by measuring the pressure difference. This measurement method is based on the laws of energy conservation and flow continuity. Intelligent throttling device (orifice flowmeter) is a new generation flowmeter that integrates flow, temperature and pressure detection functions and can automatically compensate for temperature and pressure. New technology, strong function, compact structure, simple operation and easy to use.
1: The standard throttling parts are all used and have been approved by the International Standards Organization. They can be used without actual flow calibration, and they are the only ones in the flow meter;
2: The structure is easy to copy, simple, solid, stable and reliable performance, and low price;
3: A wide range of applications, including all single-phase fluids (liquid, gas, steam), and some mixed-phase flows. There are products in the pipe diameter and working state (temperature, pressure) of the general production process;
4: Detection parts and differential pressure display instruments can be produced separately from different manufacturers, and they can be produced on a professional scale.
1: The repeatability and accuracy of the measurement belong to the medium level in the flowmeter. Due to the intricate influence of many factors, the accuracy is difficult to improve;
2: The range is narrow. Because the flow coefficient is related to the Reynolds number, the general range is only 3: 1 to 4: 1;
3: There are longer straight pipe length requirements, which are generally difficult to meet. Especially for larger pipe diameters, the problem is more prominent;
4: Large pressure loss;
5: The orifice plate uses the acute angle line of the inner hole to ensure accuracy, so it is sensitive to corrosion, wear, scaling, and dirt. It is difficult to guarantee the accuracy for long-term use.
6: The flange connection is used, which is prone to run, run, drip, and leak problems, which greatly increases the maintenance workload.
特点▲ 孔板流量计节流装置结构易于复制，简单、牢固，性能稳定可靠，使用期限长，价格低廉。 3. Orifice flowmeter characteristics ▲ Orifice flowmeter throttling device structure is easy to copy, simple, sturdy, stable and reliable performance, long service life and low price.
▲ Orifice plate calculation adopts international standards and processing.
▲ Orifice flowmeters have a wide range of applications. All single-phase flows can be measured, and some mixed-phase flows can also be applied.
▲ The standard throttling device can be put into use without actual flow calibration.
▲ Orifice flowmeter installation is simpler, no pressure pipe is needed, and it can be directly connected to differential pressure transmitter and pressure transmitter.
Fourth, the characteristics of intelligent orifice flowmeter ▲ using imported single crystal silicon intelligent differential pressure sensor.
▲ High precision and perfect self-diagnostic function.
▲ Smart orifice plate flowmeter The range of the smart orifice plate flowmeter can be adjusted by self programming.
▲ The intelligent orifice plate flowmeter can simultaneously display the accumulated flow, instantaneous flow, pressure, and temperature.
▲ In addition to the online and dynamic full compensation function, the smart orifice plate flow meter also has self-diagnosis and self-setting range.
▲ Equipped with multiple communication interfaces.
▲ High stability.
▲ Wide range, greater than 10: 1.
V. Technical Specifications of Intelligent Orifice Flowmeter ▲ High precision: plusmn; 0.075%
▲ High stability: better than 0.1% FS / year ▲ High static pressure: 40MPa
▲ No need to adjust for 5 years of continuous operation ▲ Can ignore the effects of temperature and static pressure ▲ Resistant to high overpressure
Among the many measuring instruments for fluid flow, the most common type of throttling flow meter is the orifice flow meter, but many users who use the orifice flow meter for the first time are still unfamiliar with its installation method. The technicians from Xiang Instrument Factory will briefly introduce the installation of orifice flowmeters for users, and hope to help everyone:
Conditions and steps for installing the orifice plate flowmeter:
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 correction coefficient.
3. In order to ensure that the fluid flow forms a fully developed turbulent velocity distribution at 1D in front of the throttle, and to make this distribution into a uniform axisymmetric shape, so:
的安装方法 Installation method of orifice plate flowmeter
(1) The straight pipe section must be round, and the roundness requirements for the front 2D range of the throttle are extremely strict, and there is a certain roundness index. Specific measurement method:
A. On the four vertical pipe sections of OD, D / 2, D, and 2D in front of the throttle, measure at least four individual diameters of the inner diameter of the pipe at approximately equal angular distances, and take the average value D. The difference between the single measured value of any inner diameter and the average value must not exceed ± 0.3%
B. After throttling, at the OD and 2D positions, use the above method to measure 8 internal diameter single measurement values. When comparing any single measurement value with D, the maximum deviation must not exceed ± 2%.
(2) A sufficiently long straight pipe section is required before and after the throttling member. This long enough straight pipe section is related to the form of the local resistance member in front of the throttle member 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 throttle can be in the form of the second resistance member and β = 0.7 (regardless of the actual β value). 2.
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 cable and power cable according to the flowmeter installation instructions.
6. Open the inlet and outlet valves, and the opening of the inlet and outlet valves 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 the stainless steel three-valve balance valve after the fluid passes through the flow meter.