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That's Right, That's Tight
Metal Sealed Meters and Controllers
The instruments feature high surface quality and are of modular construction with metal-to-metal seals that ensure long-term leak tightness. Metal sealed Mass Flow Meters/Controllers can be supplied in ranges starting from 0.1...5 sccm up to 0.6...100 slm (based on N2) or even higher on request. Metal sealed Pressure Meters/Controllers are available in pressure ranges from 0.1...5 psi up to 18...900 psi absolute or gauge.
Both Mass Flow Meters / Controllers and Pressure Meters / Controllers are applied across a huge range of applications, for example in the fabrication of gas compositions, for CVD and PVD, optical glass coatings, LED production, in vacuum technology and solar power (Photo-Voltaic) element manufacturing and also in semiconductor processes such as ion implantation, etching processes and atomic layer deposition (ALD).
Depending on the chemical properties of the process gases and the level of particle cleanliness required, equipment builders often prefer to apply metal sealed equipment over those with elastomeric seals.
Bronkhorst High-Tech has many years of experience supplying precise and reliable instruments for demanding high-purity applications, distinguishing themselves by unique metal-to-metal seals with excellent resealing capability.
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Dirt B. Gone
In Line Filters
 Inherent to its construction, a thermal mass flow meter or controller for gases is sensitive to contamination. To increase the MTBF (Mean Time Between Failure) it is important to make sure that the gas entering the instrument is clean.
The IN-LINE Filter Assembly, screwed into the inlet of the instrument, provides this service. It contains a 316L sintered metal filter cartridge that is suitable for general purpose filtration and can be cleaned with a suitable solvent. If the gas contains a large particulate content, we advise the use of a pre-filter.  Choose a low-flow or medium-flow style filter for instruments with 1/4" female thread at the inlet; the high-flow filter is suitable for mounting into instruments with 1/2" female thread. In principle select finest porosity with low ΔP; preferable ΔP not higher than 250 to 500 mbar, and porosity not bigger than 5 μm. |
Very Little Difference
Low ΔP Flow
 In a number of applications for measuring and controlling gas flows there is only a little differential pressure available and/or allowable. These are the applications for which Bronkhorst High-Tech developed the LOW- ΔP-FLOW series, in which the flow resistance is minimized by using a large bore capillary (thermal bypass sensor) in combination with a cylindrical flow splitter (laminar flow element).
Based on this concept, mass flow capacities between
0...10 mln/min and 0...1000 m3 n/h can be measured. At a flow up to 2 ln/min a pressure drop of less than 1 mbar is required.
Furthermore, the larger flow channels minimize the risk of clogging and facilitate the cleaning and purging of these LOW-ΔP-FLOW instruments, which will contribute to a significantly longer lifetime when the instruments are used on corrosive gas service. All fluid wetted parts are of electro-polished stainless steel. Optionally the flow meter body, sensor and flow element can be supplied in
Hastelloy or Monel.
The control of mass flow with small pressure difference comprises the LOW-ΔP-FLOW Mass Flow Controllers in compact construction. The integrated proportional, electromagnetic control valves of these MFC's have extremely fast and smooth control characteristics. Depending on the operating properties, the maximum flow in these models is 1...50 ln/min air-equivalent.
For the control of higher flow rates at very low differential pressures Bronkhorst have devised special control valves with pressure compensation bellows. These control valves are close-coupled to the flow meter while the electric PI-control function is an integral part of the flow meter. This valve has proven to be an excellent alternative to large, slow and expensive servo driven valves.
The LOW-ΔP FLOW series have been successfully applied in a wide variety of both OEM and laboratory applications such as:
> Environmental air sampling at atmospheric conditions
> Leak rate and permeability measurements
> Burner control
> Measurement of gas consumption, for example of natural gas, in low pressure gas distribution systems
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Good to Know
Supply Voltage and I/O Signals
 Bronkhorst offers a wide variety of possibilities for electrical hook-up and communication.  As a standard all mass flow and pressure meters & controllers can be fed with 15 or 24 Vdc.
The options for analog input/output are 0-5 Vdc, 0-10 Vdc, 0-20 mA and 4-20 mA (other on request).
 Digital communications of virtually all product lines are: RS232, Profibus-DP, DeviceNet, Modbus and FLOW-BUS (Bronkhorst fieldbus). |
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Bronkhorst manufactures 