f=St×V/d   

應用領域

What is Vortex flow meter

Composition of vortex flowmeter[edit]

A vortex flowmeter comprising: a flow sensor operable to sense pressure variations due to vortex-shedding of a fluid in a passage and to convert the pressure variations to a flow sensor signal,in the form of an electrical signal;and a signal processor operable to receive the flow sensor signal and to generate an output signal corresponding to the pressure variations due to vortex-shedding of the fluid in the passage.^[2]

Working principle[edit]

When the medium flows through the Bluff body at a certain speed,an alternately arranged vortex belt is generated behind the sides of the Bluff body, called the “von Kármán vortex“. Since both sides of the vortex generator alternately generate the vortex,the pressure pulsation is generated on both sides of the generator,which makes the detector produce alternating stress. The piezoelectric element encapsulated in the detection probe body generates an alternating charge signal with the same frequency as the vortex, under the action of alternating stress. The frequency of these pulses is directly proportional to flow rate. The signal is sent to the intelligent flow totalizer to be processed after being amplified by the pre-amplifier.

In certain range of Reynolds number(2×10^4~7×10^6),the relationship among vortex releasing frequency, fluid velocity, and vortex generator facing flow surface width can be expressed by the following equation:^[3]

              f=St×V/d   

Wherein, f is the releasing frequency of Carmen vortex,St is the Strouhal number, V is velocity, and d is the width of the triangular cylinder.^[4]

Vortex Flow meter application

1.Smart piping monitor

The primary reason thermal mass flow meters are popular in industrial applications is the way they are designed and built. They feature no moving parts, nearly unobstructed straight through flow path, require no temperature or pressure corrections and retain accuracy over a wide range of flow rates. Straight pipe runs can be reduced by using dual-plate flow conditioning elements and installation is very simple with minimal pipe intrusions.

However, in many applications, the thermal properties of the fluid can be dependent upon fluid composition. In such applications, varying composition of the fluid during actual operation can affect the thermal flow measurement. Therefore, it is important for the thermal flow meter supplier to know the composition of the fluid so that the proper calibration factor can be used to determine the flow rate accurately. Suppliers can provide appropriate calibration information for other gas mixtures, however the accuracy of the thermal flow meter is dependent on the actual gas mixture being the same as the gas mixture used for calibration purposes. In other words, the accuracy of a thermal flow meter calibrated for a given gas mixture will be degraded if the actual flowing gas has a different composition.^[2]

2.CVD machine

What is CVD

hemical vapor deposition (CVD) is a vacuum deposition method used to produce high quality, high-performance, solid materials. The process is often used in the semiconductor industry to produce thin films.

In typical CVD, the wafer (substrate) is exposed to one or more volatile precursors, which react and/or decompose on the substrate surface to produce the desired deposit. Frequently, volatile by-products are also produced, which are removed by gas flow through the reaction chamber.

Microfabrication processes widely use CVD to deposit materials in various forms, including: monocrystalline, polycrystalline, amorphous, and epitaxial. These materials include: silicon (dioxide, carbide, nitride, oxynitride), carbon (fiber, nanofibers, nanotubes, diamond and graphene), fluorocarbons, filaments, tungsten, titanium nitride and various high-k dielectrics.

3.Valve manifold box/panel (VMB/VMP)

What is VMB/VMP

Through our experiences of handling gases, we have acquired the knowledge to design and manufacture gas panel (gas box) of EPI system and MOCVD, material supply system etc.
Achievements in our business, we are able to design and manufacture to meet customer’s request (price and specification). We can handle the hub ring air supply of liquefied gases not just only normal gases. We also support with var-ous kind of legal application.