One can recalibrate a flow meter by having a company or owning a flow meter supplier or using a flow meter lab. No matter what type of flow meter they need to be checked to see if they need to be recalibrated regularly.
The purpose of a flow meter is to measure the flow of either air or water. They allow one to measure the total volume of air or liquid flow and the rate of the flow.
You can find a guide on reading a fuel flow meter from sites with topics on flow metering or specifically fuel flow meters. The Flow Meter Directory is one such site. You can also use FloScan Australia which is a leading manufacturer of fuel flow meters.
one meter
The orifice meter is used with the orifice flow rate meter and measures things like the flow rate of natural gas. It can measure other things and companies use it for different things also. Some companies give lessons or classes in using the orifice meter.
It would be one meter.
An ultrasonic flow meter is used to determine how fast a fluid is moving. Ultrasonic flow meters can be purchased on the internet from ZORO Tools, Northern Tool, and Grainger Industries.
To monitor a one's ability to breathe out air.
it does not have one lover
One can find a meter for water flow from the following retailers: Amazon, India Mart, eBay, Buy GPI, Flowmeter India, Zapmeter, Flowmeters, Grainger, to name a few.
There are a number of places where one may purchase an air flow meter. Online one may look at Advanceautoparts, or Autopartswarehouse. A good offline retailer to try is Advance Auto Parts.
Newton per square meter is a unit of pressure; cubicmeter per second is a measure of air flow. I don't think it makes sense to convert one to the other.
Meter is usually abbreviated with "m" , so one meter would be 1 m.