The Standard Orifice Flowmeter is a differential pressure flow measurement device with a long history of proven performance and comprehensive experimental data. It features simple construction with no moving parts, ensuring long-term stability and reliability.
Compliant with international standard ISO 5167 and Chinese national standard GB/T 2624, it can be put into use without actual flow calibration — making it unique among flow sensors.
It is widely used in industries including steam boilers, petroleum, chemicals, steel, power generation, water conservancy, papermaking, pharmaceuticals, food processing, and chemical fibers. Differential pressure flowmeters account for an estimated 75%–85% of all flow instruments in use today.
| Diameter | DN25～DN2400 |
| Accuracy | 0.5， 1.0， 1.5 |
| Temp. range | -10℃-+450℃ |
| Pressure | 0.6-16MPa |
| Medium | Steam, water, air, natural gas,… |
| Explosion-proof | ExibⅡCT5 |
| Parameter | Specification |
| Nominal Diameter | DN25 – DN2400 mm |
| Nominal Pressure | ≤42 MPa |
| Operating Temperature | -50°C to 550°C |
| Aperture Ratio (β) | 0.10 – 0.75 |
| Accuracy Class | 1.0 / 1.5 / 2.0 |
| Connection | Welding, flange, threaded, or custom |
When fluid passes through a throttling element (orifice plate) installed in a pipe, the flow stream contracts locally, increasing velocity at the restriction. This creates a static pressure difference (ΔP) between the upstream and downstream sides. The greater the flow rate, the larger the pressure difference. By measuring this ΔP with a differential pressure transmitter, the flow rate can be calculated based on the law of energy conservation and the continuity equation.
In addition to regular products, we support customization
L G B K D 50 2 (Example)
| Position | Code | Meaning |
| 1st – Product Series | L | Flow meter |
| 2nd – Supply Form | Z | Throttling device with front and rear straight pipe sections |
| G | Throttling component | |
| 3rd – Throttling Type | B | Orifice plate |
| P | Nozzle | |
| C | Long nozzle | |
| W | Venturi tube | |
| H | Quarter round hole plate | |
| Q | Circular orifice plate | |
| T | Lens orifice plate | |
| S | Double orifice plate | |
| K | Annular orifice plate | |
| J | Wing wind measuring device | |
| SW | Double Venturi tube | |
| Z | Uniform velocity tube | |
| VZ | Conical tube | |
| X | Wedge-shaped tube | |
| D | Porous orifice plate | |
| 4th – Pressure Tapping | K | Ring chamber pressure tapping |
| F | Flange pressure tapping | |
| J | Radial distance pressure tapping | |
| Z | Straight hole angle connection pressure tapping | |
| B | Eight slot orifice or eight slot nozzle | |
| H | Welded orifice/nozzle special pressure tapping | |
| X | Current limiting orifice plate | |
| 5th – Nominal Pressure | A | 0.25 MPa |
| B | 0.6 MPa | |
| C | 1.0 MPa | |
| D | 1.6 MPa | |
| E | 2.5 MPa | |
| F | 4.0 MPa | |
| G | 6.4 MPa | |
| H | 10 MPa | |
| T | 16 MPa | |
| 6th – Nominal Diameter | — | Outer diameter × wall thickness or nominal diameter |
| 7th – Supply Scope | — | See supply scope code table below |
Supply Scope Code
| Code | Scope of Supply |
| 1 | Throttling component only |
| 2 | Throttling component + clamping ring (ring chamber) pressure device + pressure short pipe |
| 3 | Throttling component + ring chamber pressure device + installation flanges + fasteners + pressure short pipes |
| 4 | Throttling component + flange pressure device or installation flanges + fasteners + pressure short pipes |
| 5 | Throttling component + pressure device + welded front/rear straight pipe sections + fasteners + pressure short pipes |
| 6 | Throttling component + pressure device + front/rear straight pipe flanges + fasteners + pressure short pipes |
| 7 | Throttling component + pressure device + front/rear straight pipe sections + user pipeline flanges + fasteners + pressure short pipes |
| 8 | Special integral concealed orifice plate + pressure short pipe |
| 9 | Venturi tube + pressure short pipe |
| 10 | Supporting differential pressure transmitter |
Product Specifications & Supply Scope Table
| Throttling Component | Pressure Tapping Method | Model | Nominal Diameter | Nominal Pressure (MPa) | Supply Code |
| Standard Orifice | Ring chamber (angle connection) | LZBK | DN50–400 | 0.25–6.4 | 5, 6, 7, 10 |
| Ring chamber | LGBK | DN50–400 | 0.25–6.4 | 1, 2, 3, 10 | |
| Straight drill hole | LGBZ | DN400–2500 (0.25–0.6); DN400–600 (1.0–1.6) | 0.25–1.6 | 1, 4, 10 | |
| Flange tap | LZBF | DN50–400 | 1.6–6.4 | 5, 6, 7, 10 | |
| Flange tap | LGBF | DN50–400 (1.6–6.4); DN400–600 (0.25–1.6); DN400–2500 (0.25–0.6) | 0.25–6.4 | 1, 4, 10 | |
| Radial distance | LZBJ | DN50–500 | 0.25–6.4 | 5, 6, 7, 10 | |
| Radial distance | LGBJ | DN50–500 (0.25–6.4); DN400–600 (0.25–1.6); DN400–2500 (0.25–0.6) | 0.25–6.4 | 1, 4, 10 | |
| Standard Nozzle | Ring chamber | LZPK | DN50–500 | 0.25–6.4 | 5, 6, 7, 10 |
| Ring chamber | LGPK | DN50–500 | 0.25–6.4 | 2, 3, 10 | |
| Venturi Nozzle | Corner/radial distance | LGWJ | DN65–1000 | 0.25–6.4 | 4 |
| Small Orifice | Ring chamber | LGBK | DN15–40 | 0.25–10 | 1, 2, 3, 5, 6, 7, 10 |
| Flange tap | LGBF | DN15–40 | 0.25–10 | 1, 4, 5, 6, 7, 10 | |
| Eight Slot Orifice | Special | LGBB | DN50–400 | 3.9–10 | 1, 4, 10 |
| Eight Slot Nozzle | Special | LGPB | DN50–400 | 3.9–10 | 1, 4, 10 |
| Welded Orifice | Special | LGBH | DN50–400 | 3.9–10 | 4, 10 |
| Welded Nozzle | Special | LGPH | DN50–400 | 3.9–10 | 4, 10 |
| High Pressure Lens Orifice | Special | LGBT | DN15–125 | 32 | 4, 10 |
| Circular Perforated Plate | Corner connection | LGQK | DN50–400 | 1.0–2.5 | 4, 10 |
| Corner connection | LGQZ | DN400–2500 | 0.25–1.6 | 4, 10 | |
| Double Orifice | Corner connection | LGSK | DN50–400 | 1.0–4.0 | 1, 2, 3, 5, 6, 7 |
| Quarter Round Plate | Corner connection | LGHK | DN50–400 | 0.6–4.0 | 2, 3, 10 |
| Direct drilling | LGHZ | DN50–400 | 0.6–4.0 | 2, 3, 10 | |
| Limiting Orifice | — | LGBX | DN15–150 | 0.6–10 | 1, 4, 5, 6, 7 |
| Venturi Tube | Radial distance | LZWJ | DN50–1600 | 0.25–1.6 | 9, 10 |
| Concealed Integral Orifice | Special | LGBN | DN45–200 | 18.4–32 | 8, 10 |
| Annular Orifice | Radial distance | LGKJ | DN40–2600 | 0.6–32 | 4, 5, 6, 7, 10 |
| Wing Wind Measuring Device | Special | LGJY | DN300–3000 | 0.1–1.6 | 4, 5, 6, 7, 10 |
| Integrated Orifice | Special | YTLGBH | DN25–4000 | 0.6–40 | 3, 4, 5, 6, 7, 10 |
| Uniform Velocity Tube / Annubar | Special | LGZ | DN50–3200 | 0.25–10 | Single piece or complete set |
| Conical Tube Flowmeter | Special | LGVZ | DN15–3000 | 0.6–40 | Single piece or complete set |
| Double Venturi Tube | Special | LGSW | DN200–4000 | 0.25–2.5 | Concealed or plug-in |
| Wedge Flowmeter | Special | LGX | DN50–500 | 0.6–40 | Single piece or complete set |
| Porous Orifice Plate | Corner connection | LGDK | DN50–400 | 0.25–6.4 | 3, 4, 5, 6 |
| Flange tap | LGDF | DN50–1200 | 10–32 | 7, 10 |
Orifice plate flow meters are suitable for flow measurement of liquids, gases, and steam under single-phase conditions—including water, compressed air, natural gas, steam, oil products, and chemical process fluids.
In the power industry, accurate steam flow measurement is crucial for power plant operation. A large power plant needed to measure the flow rate of high-temperature, high-pressure steam during power generation. After comparing various options, they ultimately chose Sino-Inst’s orifice plate flow meters.
Engineers at the power plant stated that the orifice plate flow meters performed exceptionally well under high-temperature, high-pressure conditions, accurately measuring steam flow. Furthermore, the orifice plate flow meters have a fast response time, enabling real-time monitoring of steam flow changes, providing vital data support for the power plant’s operation. During the power plant’s production process, the orifice plate flow meters demonstrated excellent stability, with virtually no malfunctions, significantly improving power generation efficiency and safety.
By using orifice plate flow meters, the power plant not only improved power generation efficiency but also reduced production costs. This case fully demonstrates the wide application and superior performance of orifice plate flow meters in the power industry.
Orifice plate flow meters perform exceptionally well in practical applications, meeting the flow measurement needs of various industries. Whether in the chemical, petroleum, power, food, or environmental protection sectors, orifice plate flow meters demonstrate advantages such as high accuracy, high reliability, and low maintenance costs. If you are looking for a reliable flow measurement device, consider an orifice plate flow meter; it may bring unexpected improvements to your production processes.
Zhang Wei, possesses 20 years of experience as an automation instrumentation engineer, specializing in the research, design, installation, commissioning, and maintenance of automation instruments.
Face to various instrument communication protocols (such as Modbus, Profibus, etc.), with solid hardware circuit design and software programming skills (proficient in C language and PLC programming). Has extensive project experience; projects he has led and participated in have all achieved outstanding results, improving product accuracy, reducing costs, and increasing production efficiency.
Possesses excellent communication and coordination skills and a strong team spirit, enabling him to quickly respond to customer needs and provide high-quality automation instrumentation solutions.
