Balanced flowmeter

I. Overview

Balanced flowmeter is a new type of throttling flow sensor developed based on standard orifice plates and flow regulators. Balanced flow meters can be used downstream for various disturbances, providing excellent performance with the shortest straight pipe installation.

2、 Measurement principle

A balanced flowmeter is a throttling flow sensor. It adopts an adjuster type orifice plate structure, which can be applied in situations where there are turbulent flow field factors upstream.

Flow calculation formula:

In the formula, qm and qv represent mass flow rate (kg/s) and volume flow rate (m3/s), respectively;

C - outflow coefficient;

ε - coefficient of expandability;

D - diameter of the throttle opening, m；

β - diameter ratio, β=d/D；

D - Inside the pipeline, m；

ρ 1- Density of the measured fluid, kg/m3;

Δ p - differential pressure, Pa；

3、 Characteristics

1. High linearity and good repeatability

The balanced flow sensor has a symmetrical porous structure, which can balance the flow field, reduce eddy currents, vibrations, and signal noise. The stability of the flow field is greatly improved, and the linearity is 5-10 times higher than that of the orifice plate. The repeatability is increased by 54%, which is 0.15%. From its comprehensive performance, the balanced flow meter belongs to the high-end flow meter category.

2. Low requirements for straight pipe sections

Due to the stable flow field and twice the speed of pressure recovery compared to orifice plates, balanced flow sensors greatly reduce the requirement for straight pipe sections. The front and rear straight pipe sections are generally 3D and 1D, with a minimum of less than 0.5D, thus eliminating a large number of straight pipe sections, especially for pipelines made of special and expensive materials.

3. Reduce permanent pressure loss

The porous symmetrical balance design reduces turbulent shear forces and vortex formation, reduces kinetic energy loss, and reduces permanent pressure loss by 2.5 times compared to orifice plates under the same measurement conditions, thereby saving considerable operating energy costs. It is an energy-saving instrument.

4. Resistant to dirt and not easily clogged

The porous symmetrical balance design reduces the formation of turbulent shear forces and eddies, greatly reducing the formation of dead zones, ensuring the smooth passage of dirty media through multiple holes, and reducing the chance of fluid holes being blocked.

5. Can directly replace the orifice plate

The balanced flow sensor has the same usage method and appearance as the orifice plate, so it can be directly replaced without any changes in piping or related instruments. It is very suitable for the energy metering transformation of the entire plant to replace the orifice plate with a balanced flow meter.

6. Wide flow measurement range

Based on the experimental results, we have learned that balancing the performance of the flowmeter allows its flow rate to range from minimum to supersonic; Its minimum Reynolds number can be lower than 200, and its maximum Reynolds number is greater than 107; The beta value can be selected from 0.25 to 0.90.

7. Good long-term stability

Due to the significant reduction in turbulent shear force, the direct friction between the medium and the throttling element is greatly reduced, and its β value remains unchanged for a long time. The entire instrument has no movable parts, so it can maintain stability for a long time.

8. Measurable high temperature and high pressure medium

Like orifice plates and other throttling devices, the working temperature and pressure depend on the material and grade of the pipeline and flange. The working temperature can reach 850 ℃ and the working pressure can reach 42MPa.

9. Measurable complex working condition medium

Due to its unique structural design, it has special properties and can be used for gas-liquid two-phase, slurry, and even solid particle measurements. Balanced flow can measure bidirectional flow.

4、 Main technical parameters

1. Pipeline size: 15 ≤ D ≤ 600 mm (special orders can be placed if exceeding this range)

2. Nominal pressure: PN ≤ 16MPa (special orders can be made if exceeding this range)

3. Aperture ratio: 0.25 ≤ β ≤ 0.90

4. Reynolds number range: When 0.25 ≤ β ≤ 0.90, 200 ≤ ReD ≥ 107

5. Accuracy: Level 0.5