i need some practical information about "bubble flow meter"for measuring the pumping speed of rotary van vacuu
610945
Bubble meters are good ways of measuring small air flow rates. They are available from scientific equipment dealers. \n\nThe meter sets up a bubble film that goes straight across a clear plastic pipe. As the air moves through the pipe, the bubble film move up the pipe. Two detectors measure the time it takes for the film to travel up the pipe a certain distance. Knowing the time difference, the distance between the detectors, and the diameter of the plastic tube gives you the flow rate.  Once you see it working, the concept is pretty simple.
453046
A device for passing measured amount of gas or compressed air under constant pressure through gas meters to test accuracy of meters.\n\nkindly check below websites also :)
900972
You could use a turbidometric method that could detect the diffraction of light through the liquid and correlate it with the amount of microbial growth in it.  \n\nYou could also use a calibrated loop to plate the liquid and then count colonies.  I know they do this with urine cultures in hospital labs at times.  The loop picks up a certain amount of liquid like 10 microliters or so and then you can correlate the growth with this 10 microliter figure.
580210
Most fluid flow handbooks have this information. The Foxboro company use to have the very best manual for this.You might find one on ebay. Many thermodynamics text books also have this information.
1050457
You can make an estimate but there are many variables that will keep the answer from being very accurate. Just getting the differential pressure between two points (I assume that is what you mean by knowing the pressure) is quite a task. You would need to measure the pressure at each  point at the exact time to within a psi or so. Then you must know the distance between the two points, the specific gravity of the gas, its weighted average temperature and its compressibility. \n\nIt is not clear what kmclean48 means by a DP meter. Is this a pitot tube or what? I assume you mean to measure flow without installing any type of meter.  If you do use a pitot tube, you will need to run a traverse to be sure you get the correct average velocity.\n\nFinally the various gas flow formulas (there are many) will yield different results.
657436
I assume the pump performance curve is unavailable, pity. You know what the current rpms, pressure and power is. I would apply the pump affinity laws in order to determine what the increase in rpm(flow) and power it will take to make the pressure you require. It may be  easier getting a bigger motor for the existing pump, than going through the time and effort of a single new pump, pumps in series, piping reconfiguration etc, all of which will work.
422147
graduated cylinder... although you get a higher degree of accuracy with volumetric pipettes. :-)
526702
The only way to know is to try it! Get one of those 12V compressors for inflating car tyres and connect to the bottle with a pressure gauge that reads +200psi. Cover the bottle with some sort of containment device like a laundry basket leaving the guage exposed so you can read it with a pair of binoculars. Turn on the pump and stand well back..!
575219
There are various methods. the method to be used is selected as per the conditions. Following are the most common of them.\n\n1) Use of head type flow meters like orifice or venturi\n2) Use of annubar, pitot tube\n3) Use of ultrasonic/ UV transmitter reciever or doppler frequency shift system\n\nFor details, following books can be referred\n1) Instrument Engineer's handbook- Bela G Liptak\n2) Measurement Systems- E. O. Doeblin
1097124
Aplly the following formula:\n\nG = w * A, where:\n\nG - flow rate [m^3/s]\nw - speed of fluid [m/s]\nA - transversal section area of the pipe [m^2]
713107
range/amount\n\nrange = 120 mV (90mv - (-30mV))\namount = 2^16 = 64*1024\n\nplug-n-chug
794147
You might work up some Q&A while showing this old demo of the effect of atm pressure...thereby adding some visual interest to the subject.\n\nAdd a few oz of water to a square-sided, metal, one-gallon can having a tightly fitted cap...bring to a vigorous boil (cap now off, please :-))..) and continue boiling until all air is expelled...screw cap in place and allow to cool...they will see the can collapse.\n\nWork up questions about the vacuum thus created (by the condensation of the water vapor) allowing atm pressure to exert its force.
430387
I believe from my old chem eng days before I gave that up to become a model that a positive displacement pump is where the liquid is forced though the device by changing the volume of the pump e.g. a piston. Their operating characteristics are therefore relatively independant of pressure but they are less efficient with high volumes \n\nOther types of pumps e.g. centrifugal do not change the volume of pump or force liquid in the same way but rather alter the pressure by 'flinging' the liquid.
540682
This gives a detailed explanation of how they work.\n\nhttp://en.wikipedia.org/wiki/Bubble_light
1169821
Here are some sites. Don't know exactly what you're looking for.\n\nhttp://www.lmnoeng.com/Flow/SmallOrificeGas.htm\nhttp://www.mysolv.com/OrificeCalcIn.asp\nhttp://www.gpengineeringsoft.com/pages/pdtpipedrop.html\nhttp://www.eng-applications.com/orifice.htm\nhttp://www.controlengineering.se/flowcalc/flowcalceng.htm\nhttp://www.pipeflowcalculations.com/
607494
An orifice plate will work but in general it is not a good idea to restrict the flow to the suction of a compressors because it reduces the performance.\n\nIs this a centrifugal or reciprocating compressor? On centrifugal compressors as a part of the surge control system it is not uncommon to use a pitot tube device to see changes in flow rate. A pitot tube has very little pressure drop and since you want acfm on the suction for surge control, it makes sense to measure the flow at the suction rather than the discharge.\n\nFor reciprocating compressors there is very little reason to measure flow on the suction. It is typically measured on the discharge where the pressure is higher and pressure loss from the orifice plate is not as significant.
303247
Here is a great web site you can compare various kinds of pumps. Best Wishes..\n\nhttp://www.diabetesnet.com/diabetes_technology/insulin_pump_models.php