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Deep Breath
Medical Gas Measurement and Totalization
 There are several applications for the measurement and totalization of medical gas which can be on either primary or secondary gas networks.
On primary networks the need for measurement can be for:
- Separated invoicing for hospital/clinics/laboratories/departments sharing the same source of medical gas
- Monitoring and consumption data acquisition
- Leak detection on gas line, on safety vent and on medical gas source
On a secondary network there are similar needs for measurement and totalization:
- Independent gas consumption invoicing between the health institution departments
- Overconsumption detection
- Monitoring and consumption data acquisition
- Leak detection on gas line
 The MASS-STREAM™ mass flow meters and controllers from M+W Instruments (a Bronkhorst company) are available for flow ranges from 10...200 mln/min up to 500...5000 ln/min Air equivalent. The majority of instruments for gas consumption measurement are sold with our optional multi-functional display for local viewing and control.
Important Features include:
- Wetted part: stainless steel 316 and EPDM (seals without fluorine): no reaction between gases and mass flow meter
- Degreased instrument: standard (for all gases)
- Electromagnetic compatibility (CE labeling)
- Thru-flow measurement (no by-pass): no risk of clogging, no wearing
- No moving parts inside: long life of mass flow meter.
- Optional fittings: Brass for copper pipes or stainless steel for stainless steel pipes: compatible with medical pipe (degreased)
- Optional display: multi-functional, local reading possible
Communication features:
- Instrument setup for medical application:
- Counter enabled / counter reset enabled or disabled / selected counter unity can be changed / gas selection possible / ...
- Instrument setup for remote information reporting and communications:
- Analog output signals: 4...20 mA / 0...20 mA / 0...5 V / 0...10 V
- Digital communication: RS232
- Digital interfaces: Modbus-RTU , Flow-Bus, DeviceNet™, Profibus-DP®
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Small and Mighty
Micro Fluidic Flow and Pressure
The use of micro fluidic devices for research and analytical purposes has some important advantages. Firstly, because the internal volumes within the instruments are very small, the analysis will be faster and the amount of reagents and analytes used can be reduced. The latter is especially significant for expensive reagents. Furthermore, the physical dimensions are much smaller than those of conventional devices. This enables Life Sciences system integrators to downscale the size, inherently reducing the costs of ownership of their equipment. Also, the availability of compact and lightweight instruments could lead to the development of portable systems.
 Previously, conventional mass flow and pressure meters and controllers have needed a footprint of 1.5", as for instance specified in the NeSSITM system. Bronkhorst has developed the IQ+FLOW mass flow sensor; the smallest mass flow and pressure meter/controller in the world!
Due to the use of micro system technology (MST), Bronkhorst has been able to halve the footprint dimension to 0.75", thereby realizing ultra-compact flow controllers for flow rates from 0.2 to 5000 sccm (mln/min) and pressure controllers for 0.3 to 150 psi.
 Thanks to the modular concept of the IQ+FLOW series, multiple channel arrangements can be realized on one compact manifold, with one multi-channel digital pc-board (per 3 channels) in one housing.
With our unsurpassed expertise in the field of low flow measurement and control of both gases and liquids, Bronkhorst offers precision equipment that is ideally suited to meet the critical requirements of micro fluidic research and system integration.
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See it Happen
CORI-FILL™ on You Tube
Bronkhorst Cori-Tech has posted a video showing
CORI-FILL™ dosing in action.
The World's Smallest Coriolis Meter/Controller!
The Word's Lowest Flow Coriolis Meter/Controller!
See it by clicking here: CORI-FILL™
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Good to Know
Thermal Mass Flow: Bypass vs. CTA
Thermal mass flow instruments use temperature, as their name suggests, in calculating mass flow. There are, however, several ways to use temperature to calculate mass flow.
Thermal mass flow instruments that use a bypass (capillary bypass, bypass sensor) are what most people have in mind when they think of thermal mass flow instruments. In these instruments power is applied to heat the sensor tube and then the temperature of the tube is measured at two points.
With no flow the temperature differential between the two points will be zero. As flow increases the temperature at the first measuring point will decrease as fluid carries away heat, and the temperature at the second measuring point will increase as the fluid carries heat to it. More flow results in a greater temperature differential. The temperature differential is directly related to mass flow.
Another technology used to measure mass flow is CTA (Constant Temperature Anemometer). In a CTA (though flow, straight tube) instrument there are two measurement "pins" inserted in to a straight tube flow path. The first "pin" both heats and measures the temperature of the fluid, and the second "pin" measures the temperature of the fluid.
Again, as fluid flow increases the fluid will carry heat from the first measuring point to the second. In a CTA, however, the power is varied to keep the temperature between the two measuring points constant, and it is this power level that is used to calculate mass flow.
Each technology has its advantages and disadvantages which generally are application specific.
A clean, dry gas where accuracy is as important as repeatability may be a better application for a bypass instrument like the Bronkhorst EL-FLOW.
An application with a dirty or slightly moist gas, or where lower accuracy is acceptable but high repeatability is required may be a better application for a CTA instrument like the M+W Mass-Stream™.
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Laws and Guidelines
Ducharm's Axiom
If you view your problem closely enough, you will recognize yourself as part of the problem.
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