Mar
31
Controlling Gas Mass Flow Rate to an Incredible 0.2 sccm
Filed Under Mass Flow Meter Videos | Leave a Comment
SierraInstruments asked:
Video shows live demonstration of controlling gas mass flow rate to an incredible 0.2 sccm with Sierra’ Micro-Trak Model 101 by Sierra Instruments. The video also features the use of the Pilot Module display interface to adjust instrument parameters.
Jon
Mar
29
Mar
27
Mar
25
Mar
24
Mar
22
Anthony Sacco asked:
In applications where ozone is generated and used for air or water treatment application, it is important to be able to know and communicate the concentration of ozone. There are techniques for measuring the ozone present in air or water, for example, the use of UV radiation at 254 nm, but there still need to be units of measure to translate these results into meaningful numbers for technicians to use.
A unit of measurement in the gas phase grams of ozone per normal cubic meter usually written as g/Nm3. the term normal in this expression is critical since a gases density is influenced by pressure. Normal in this case refers to the the conditions at which the measurement was taken, or the condition to which it has been adjusted. Normal here refers to standard pressure and temperature as agreed to internationally: P (Standard) = 1 atm or 760 mmHg or 1.01325 bar and T (standard) = 0 degrees C or 32 degrees F or 273.15 degrees K. Since actual measurements will be done at conditions most likely different than the international standards, the measurement devices are fitted with the ability to compensate for these differences and present the results in g/Nm3. Thus, the measured g/m3 value is multiplied by (P (Standard)/T (Standard)) X (T (measured)/ P(Measured)).
Another unit of measure that is often used is ppmv, which is part per million on a volume by volume basis. The measurement ppmv is proportional to g/Nm3: 466.43 ppmv = 1 g/Nm3.
Another important unit of measure is percent weight by weight (%wt/wt). This can be a very useful unit of measurement. If the mass flow of feed gas for an ozone generator is known, say by using a thermal mass flow meter, than knowing the %wt/wt will allow one to know the mass of ozone by simple multiplication. In order to derive the %wt/wt from the g/Nm3 value, one must know the density of ozone and the density of the feed gas. To calculate the %wt/wt one divides the quantity (100 X the measured g/Nm3) by the following value:
g/Nm3 – (the ratio of feed gas density to ozone density) X g/Nm3 + feed gas density
So, if the measured concentration of ozone were 100 g/Nm3 and the feed gas was oxygen (1,428.96 g/Nm3) then knowing that ozone has a density of 2,143.93 will result in a % wt/wt value of 6.84. If air is the feed gas the result would be different, i.e. about 10% lower than the value 6.84 shown above.
In water treatment applications we normally use the terms ppm, which is really part per million by weight (ppmw). We could also use the terms g/m3 since 1 g/m3 = 1 ppmw. The density of water changes very little with changing temperature. We normally are referring to dissolved ozone when we talk about the concentration of ozone in water. Since ozone is produced as a gas, care must be taken to insure that the gas bubbles have been separated from the water prior to making a measurement. Ozone can be measured using the UV method mentioned above or by an electrochemical method. Both methods can result in accurate reading in ppmw when carried out properly.
Cecil
In applications where ozone is generated and used for air or water treatment application, it is important to be able to know and communicate the concentration of ozone. There are techniques for measuring the ozone present in air or water, for example, the use of UV radiation at 254 nm, but there still need to be units of measure to translate these results into meaningful numbers for technicians to use.
A unit of measurement in the gas phase grams of ozone per normal cubic meter usually written as g/Nm3. the term normal in this expression is critical since a gases density is influenced by pressure. Normal in this case refers to the the conditions at which the measurement was taken, or the condition to which it has been adjusted. Normal here refers to standard pressure and temperature as agreed to internationally: P (Standard) = 1 atm or 760 mmHg or 1.01325 bar and T (standard) = 0 degrees C or 32 degrees F or 273.15 degrees K. Since actual measurements will be done at conditions most likely different than the international standards, the measurement devices are fitted with the ability to compensate for these differences and present the results in g/Nm3. Thus, the measured g/m3 value is multiplied by (P (Standard)/T (Standard)) X (T (measured)/ P(Measured)).
Another unit of measure that is often used is ppmv, which is part per million on a volume by volume basis. The measurement ppmv is proportional to g/Nm3: 466.43 ppmv = 1 g/Nm3.
Another important unit of measure is percent weight by weight (%wt/wt). This can be a very useful unit of measurement. If the mass flow of feed gas for an ozone generator is known, say by using a thermal mass flow meter, than knowing the %wt/wt will allow one to know the mass of ozone by simple multiplication. In order to derive the %wt/wt from the g/Nm3 value, one must know the density of ozone and the density of the feed gas. To calculate the %wt/wt one divides the quantity (100 X the measured g/Nm3) by the following value:
g/Nm3 – (the ratio of feed gas density to ozone density) X g/Nm3 + feed gas density
So, if the measured concentration of ozone were 100 g/Nm3 and the feed gas was oxygen (1,428.96 g/Nm3) then knowing that ozone has a density of 2,143.93 will result in a % wt/wt value of 6.84. If air is the feed gas the result would be different, i.e. about 10% lower than the value 6.84 shown above.
In water treatment applications we normally use the terms ppm, which is really part per million by weight (ppmw). We could also use the terms g/m3 since 1 g/m3 = 1 ppmw. The density of water changes very little with changing temperature. We normally are referring to dissolved ozone when we talk about the concentration of ozone in water. Since ozone is produced as a gas, care must be taken to insure that the gas bubbles have been separated from the water prior to making a measurement. Ozone can be measured using the UV method mentioned above or by an electrochemical method. Both methods can result in accurate reading in ppmw when carried out properly.
Cecil
Mar
19
Mass Air Flow Sensor PID
Filed Under Mass Flow Meter Videos | 17 Comments
ADPTraining asked:
Explains the MAF scanner parameter. (note: the following is NOT a sales pitch. We allow all schools and training institutions to use our software free of charge, so long as it is not sold to others. You’re encouraged to download our free automotive simulation software for more information. www.autodiagnosticsandpublishing.com
Claudia
Mar
18
Mar
18
Refrigerated Van: an Indispensable Part of the Modern Life
Filed Under Mass Flow Meter | Leave a Comment
Mar
12
Tony Bargas asked:
Painting your old cabinets tends to be one of the more affordable and homeowner-friendly home improvement projects. However, painting cabinets involves a lot of hard work to be done properly. The old finish would have to be removed and sanded down to the bear wood, then you would have to apply the primer and finally painting it, not to mention all the hardware would have to be remove also. This process is less expensive than replacing or refacing the cabinets. However, you would still have an old looking kitchen with old looking doors and all that you would have accomplished is changing the color and maybe the hardware and eventually seeing the grease stick to the painted cabinets accumulating the dust that will stick to the grease. The cost for painting your cabinets can range from $50 to $200 if done by the homeowner and $2,500 to $6,000 if a contractor is hired.
Kitchen Cabinet Refacing is the more affordable way as compared to expensive new cabinets, usually 50% less. Cabinet refacing will replace the cabinet doors and drawer fronts with new ones and the rest will be refaced to match your new cabinet doors and drawer fronts. Choose cathedral, arch, shaker, and many other styles and colors in wood or thermo-foil laminate. By replacing the doors, drawer fronts, hardware, new moldings, additional space, knick-knock shelves and other accessories available, you can design your dream kitchen.
Adam
Painting your old cabinets tends to be one of the more affordable and homeowner-friendly home improvement projects. However, painting cabinets involves a lot of hard work to be done properly. The old finish would have to be removed and sanded down to the bear wood, then you would have to apply the primer and finally painting it, not to mention all the hardware would have to be remove also. This process is less expensive than replacing or refacing the cabinets. However, you would still have an old looking kitchen with old looking doors and all that you would have accomplished is changing the color and maybe the hardware and eventually seeing the grease stick to the painted cabinets accumulating the dust that will stick to the grease. The cost for painting your cabinets can range from $50 to $200 if done by the homeowner and $2,500 to $6,000 if a contractor is hired.
Kitchen Cabinet Refacing is the more affordable way as compared to expensive new cabinets, usually 50% less. Cabinet refacing will replace the cabinet doors and drawer fronts with new ones and the rest will be refaced to match your new cabinet doors and drawer fronts. Choose cathedral, arch, shaker, and many other styles and colors in wood or thermo-foil laminate. By replacing the doors, drawer fronts, hardware, new moldings, additional space, knick-knock shelves and other accessories available, you can design your dream kitchen.
Adam