Technical Background

Flow Measurement Revolution     Licensed from NASA USA

A+K Balanced Flow Meter was initially invented by NASA to measure liquid oxygen of the spacecraft and introduced from A+FlowTek company by Shanghai Keyontechs Co., Ltd. in 2006. Up to now, Keyontechs has produced more than 50,000 sets of BFM that are widely used in oil & gas, chemical, electric power, metallurgical and other industries at home and abroad.

A+K Balanced Flow Meter integrates the function of the rectifier and throttling sensor to meet the measurement requirements whatever under high temperature & high pressure, or low temperature or other severe working conditions. A+K BFM is also with short straight pipe requirement, high accuracy, wide application, low pressure loss and other excellent performance, wining great recognition from more and more customers.

Keyontechs has patented A+K Balanced Flow Meter and calibration laboratory that is given Laboratory Accreditation Certificate by China National Accreditation Service for Conformity Assessment. Keyontechs always advances with the times, engaging in improving technology and service as per national and industry requirements. By doing so, Keyontechs has won numbers of honers.

A+K Balanced Flow Meter is in conformity with ISO-5167, GB/T-2624, JJG640 standard and installation regulations of D/P flow meters.

Basic Principle

A+K Balanced Flow Meter—Revolutionary differential pressure type flow meter. The core part of the A+K balanced flow meter is a multi-hole throttling and conditioning element mounted on the cross-section of the pipe. And the size and layout of each hole are customized according to unique equation and numerous real flow testing results, which is called function hole. When fluid is running through the function holes, the flow is rectified, at the same time, the vortex, kinetic energy loss, dead-zone effect and signal fluctuation of the pressure tapping point are significantly reduced, forming an ideal flow field. And a stable D/P signal is obtained by the pressure tapping device, then the volume or mass flow is calculated according to the Bernoulli equation.

Theoretical Formula:      

Simplified Formula for D/P and Flow Rate:   

Standard orifice plate only has one throttling hole and dead zones at the sides of the hole can form large amount of vortex which lead to kinetic energy consumption and permanent pressure loss; the noise caused by random and cluttered vortex can make the signals of pressure point fluctuate and reduce measurement linearity and repeatability; single-hole structure requires long straight pipe to make flow field adjustment and pressure recovery. 

BFM Multi-hole Throttling Element

The test and verification of A+K Balanced Flow Meter are finished by American aerospace technicians and the technology and testing data are confirmed by Tennessee A&M University. The testing result shows that A+K BFM can rectify flow field, and reduce vortex, dead zone effect, kinetic energy loss, also bring down the fluctuation of pressure points caused by vortex.

Excellent Performance

Balanced Flow Meter is with multiple advantages including high accuracy, wide turndown ration, short straight pipe requirement, low pressure loss, long-term stability, dirt-resistance, wide measuring range, wide applicability and so on. Also with personalized design and customization service, BFM enters into top grade flow meter industry.

1. High Accuracy

※ The multi-hole and symmetrical structure enables Balanced Flow Meter to rectify flow field and reduce vortex, vibration as well as signal noise, largely improving the stability of flow field. BFM also can reach 5-10 times higher accuracy compared with traditional throttling plate by adopting specialized precision pipe and pressure device.

※ According to site calibration, sensor accuracy can reach to ±0.30% - ±0.50% suitable for custody transfer.

※ According to geometric dimension verification, sensor accuracy can reach to ±0.50%, ±1.00% suitable for process control.

※ BFM is with much high machining reproducibility and can make geometric dimension verification based on site calibration data, which is as the same as traditional throttling plate.

2. Short Straight Pipe Requirement

※ Balanced Flow Meter can rectify the flow field and make pressure recovery twice as quick as traditional orifice plate, largely bringing down straight pipe requirement.

※ Balanced Flow Meter supports the minimum 0.5D straight pipe, which saves a large amount of pipe cost especially for specialized expensive pipe.

The upstream and downstream straight pipe requirements of two mutually perpendicular elbow pipes are as below:

3.  Low Permanent Pressure Loss

The multi-hole and symmetrical structure of Balanced Flow Meter can reduce vortex and turbulence to lower the kinetic energy loss. When it is under same working condition and the D/P value is kept no reduction, Balanced Flow Meter can decrease to 1/2-1/3 permanent pressure loss compared with traditional throttling plate, and save much operating cost. As a kind of energy-saving instrument, Balanced Flow Meter is reliable.

4. Wide Turndown Ratio

※Balanced Flow Meter largely improves measurement turndown ration compared with traditional throttling plate.

※ American research shows that when Reynolds number is ＞5×10⁴, the turndown ratio of Balanced Flow Meter is without upper limit if suitable pore size is chosen.

※ A+K Balanced Flow Meter can satisfy regular turndown ration 7:1-10:1 in industry measurement, but it can also reach 20:1, 30:1 and larger turndown ratio by choosing suitable parameters in many situations.

5. Dirt-resistance and Anti-clogging

The multi-hole and symmetrical structure enables Balanced Flow Meter to reduce vortex and turbulence, greatly decreasing dead zones and making sure dirty fluids smoothly running through multiple holes.

6. Wide Measuring Range

According to test results, Balanced Flow Meter can be used in fluid measurement even when flow velocity of the fluid is equal to sound velocity; its measurable Reynolds number range can be 200-10⁷; its βrange can be 0.25-0.90.

7. Great Repeatability and Long-term Stability

※ Balanced Flow Meter can rectify flow field and improve repeatability to 0.1%.

※ The multi-hole structure of Balanced Flow Meter can disperse stress and avoid the abrasion of sharp angle, keeping β value no change and improving long-term stability.

8. Wide Application Range

※ The operating temperature and pressure of Balanced Flow Meter can separately reach to or above 850℃, 42MPa, which depend on the material and rank of pipe and flange.

※ Balanced Flow Meter can be applied in liquid gases measurement and effectively prevent vaporization to achieve the best measurement results.

※ Balanced Flow Meter can be used in the measurement of dirty, slurry and other fluids.

※ The bilaterally symmetrical design is suitable for bi-directional flow measurement.